ACHARYA N G RANGA AGRICULTURAL UNIVERSITY Rajendranagar, Hyderabad – 500 030

Practical Manual

for Field Diagnosis in Agriculture Course No. Ento.333 (1+1)

(2012-13)

Editor G Raghavaiah

Professor & Head Department of Entomology

Agricultural College, Bapatla

Co-Editors Entomology Plant Pathology S.R.Koteswara Rao P.Anil Kumar G.Ramachandra Rao P. Seetha Ramu

INDEX

S.No Title of the exercise pages Signature of the Teacher

Remarks

1 Survey and methods of surveillance of crop pests and diseases –I

2 Survey and methods of surveillance of crop pests and diseases –II

3 Steps in pest and diseases diagnosis in the field

4 Agro Ecosystem Analysis (AESA) pest defender ratio adopted in farmers field school

5 Field diagnosis of important insect pests and diseases of cereals and millet crops

6 Field diagnosis of important insect pests and diseases of oilseed crops

7 Field diagnosis of important insect pests and diseases of pulses

8 Field diagnosis of important insect pests and diseases of fibre and sugar crops

9 Field diagnosis of important insect pests and diseases of vegetable crops-I

10 Field diagnosis of important insect pests and diseases of vegetable crops-II

11 Field diagnosis of important insect pests and diseases of fruit crops

12 Diagnosis of important insect pests and diseases of stored grain products and perishables-I

13 Diagnosis of important insect pests and diseases of stored grain products and perishables-II

14 Plant protection equipment and their maintenance

15 Laboratory test- isolation of plant pathogens from diseased material Test for identification of plant pathogens viz., fungi,bacteria and virus Final diagnostic report

16 Plant quarantine

Acharya N. G. Ranga Agricultural University Department of Entomology Agricultural College, BAPATLA

CERTIFICATE

This is to certify that this is a bona-fide record of practical work done by

Mr./Ms._______________________________ I.D. No. ___________ in the Course No. ENTO: 333 Field Diagnosis in Agriculture (1+1) during --- Semester 20 – 20

Signature of the Course in-charge

Ex No: 1 Survey, Methods of Surveillance of crop pe sts and diseases - I

Pest surveillance is the systematic monitoring of biotic and abiotic factors of

the crop ecosystem in order to predict the pest outbreak or it is the study of the

ecology of the pest which provides the necessary information to determine the

feasibility of a pest management programme. By the Pest surveillance programmes,

the population dynamics and the key natural mortality factors operating under field

conditions can be known which in turn helps in devising the appropriate

management strategies.

Advantages:

1. One can know how a pest / disease is multiplying in an area and when it is

expected.

2. Minimize the cost of plant protection by reducing the amount of pesticides

used and in turn reduce environmental pollution.

3. Pest / disease control measures can be initiated in time due to advance

forecasting.

4. Useful for pest / disease forecasting.

5. To find out natural enemy population

6. To study the influence of weather parameters on pests / diseases

7. Mark endemic areas

8. Maintain the stability of the agro ecosystem.

Components of pest surveillance

1. Identification of the pest / disease

2. Distribution and prevalence of the pest / disease and its severity.

3. The different levels of pest / disease incidence and the loss due to the

incidence.

4. Pest / pathogen population dynamics.

5. Assessment of weather.

6. Assessment of natural enemies etc.

This study will give advance knowledge of probable pest / disease infestation and

will help to plan cropping patterns and to get best advantage of pest / disease

control measures.

Survey requires suitable sampling techniques and sampling programmes.

1. Fixed plot survey: Choose a one acre field. Enter the field and walk at least 10 m

and start selecting 25 plants at random by zig zag walk. Record the observations at

weekly intervals

2. Roving survey: Record the observation from 10 randomly selected plants by

diagonal walk method from south west corner

Sampling Techniques: It is not feasible to take the count of every individual in the population. Instead it is usually more efficient to estimate population density by sampling.

Sampling means a representative sample of the total population. To conduct a survey and make estimation, a sampling technique is required.

A sampling technique is the method used to collect information for a single sample. Sampling technique depends upon

i) the activity of pests (flying / mobile /sessile; diurnal / nocturnal), feeding

behaviour (chewing [internal / external] or sucking).

ii) occurrence of diseases – soil borne / air borne / seed borne, part of the plant

affected / whole plant, death of the plant (incidence) / necrotic lesions on

part of the plant (eg. leaf) (severity) etc

Sampling techniques for pest incidence include direct counts, in situ counts, trapping and the use of accessory materials like light trap, pheromone trap, sticky traps etc. Sampling technique for diseases include measuring the severity or incidence of the disease.

The sampling programme includes location of the sample, number of samples and the time intervals at which samples are to be collected. The weather parameters of the respective areas are also to be recorded to study their influence on the pests / diseases. The observations on the pests / diseases cover their alternate / cultivated host crops and weed host plants.

1. Random sampling : It is the easiest method in which selection of samples will be

done randomly:

Eg: Diamond back moth: Select cabbage heads randomly and count larval

population.

Jassids: Make 10 net sweeps randomly in a field. Count the number of nymphs and

adults caught .

2. Sequential sampling : Establishment of threshold levels should be done

Eg: For fixing levels, it is essential to know the average plants and insects

3. Point sampling: It is a measure of population density designed to relate no. of

insects or their damage to the no. of plants or plant parts / acre

Eg: Collect 100 bhendi fruits or brinjal randomly for counting larvae

4. Trap sampling: Different traps are used to sample different insects, viz. Light

traps, pheromone traps and suction traps etc.

Eg: Light traps for jassids

1. Collect the insects trapped in one night, remove insects other than jassids and

weigh the sample .

2. Take two or three of such samples (1, 2 or 3 grams) and count the number of

jassids in each sample, take the average and multiply with total weight to know the

approximate number of jassids trapped in one night .

Nature of sampling: This depends on insects, its distribution and the stage of pests.

The different methods are

1. Net sweeping or trapping : In this method , the density and height of crop, no of

sweeps required and type of insects involved in the study are considered.

Eg: 10 net sweeps are sufficient to assess the general population of any insect .

2. Sudden trapping :Insects in an unit area are suddenly trapped without causing

any disturbance and trapped insects are later counted.

Eg: Polythene bags are used to monitor sorghum ear head bug on sorghum ear

heads by sudden covering.

3. Screen trap catches: A cot type screen trap is pushed over row crops and the

trapped adults are counted.

Eg: To monitor adults of gram caterpillar in cotton.

4. Narcotised collections: This method is useful for counting quick moving insects.

The insects are either killed or anaesthetized and counted

5. Light trap catch : Quantitative assessment of population abundance can be

made.

Eg: Jassids, gallmidges, Light attracted night flying Lepidopterans Eg: Stem

borers etc. The numbers of insects in the trap varies greatly from night to night .

This variation may be due to fluctuations in certain components of the weather,

partly on the density of the population and their activity.

6. Water trap : A rotation fan trap is used to collect insects associated with water

surface.

Eg: Aquatic insects

7. Suction Trap : In this method, flying insects are trapped by sucking air into trap

with a suction apparatus operated by fan or by means of motor.

Eg: Beetles, weevils, jassids, aphids etc

8. Adhesive or sticky or inspection trap: Suitable adhesive material (grease)

pasted on paper is used for collection of insects.

Eg: Whiteflies, jassids etc , Yellow sticky trap for whitefly

9. Bait trap catch: Many materials are used for bait as they stimulate food odours to

attract insects.

Eg: Fruit flies (Malathion and jaggery), sorghum shoot flies (Fish meal bait).

10. Sight counting: Counting the population by visual observation. Population of

insects in a measured area is counted.

Enter the field at least two ft away from the bund. Select a site with a dimension of 1 sq. mt. randomly. Record insect damage in percentage or population/plant

Eg: Paddy stem borer, brown plant hopper, gall midges etc.

11. Fixed volume or area of soil : Soil insects like grubs are counted from a fixed

area and depth of soil. (By cutting out cylinders of soil four inches in dia and 12

inches deep). A sample of 20 quadrates (ie 20 cylinders of soil four inches in dia)

is taken from one acre and it can be multiplied by 498,960 (the number of

quadrates that could be taken from one acre) to estimate the population in one

acre.

Eg: White grubs

12. Crop samples: The amount of damage or the number of larvae in selected

plants / tillers are noted.

Enter the field at least two ft away from the bund. Select a site with a dimension of 1 sq.mt. randomly . Record insect damage in percentage or population/plant

Eg: stem borers, rice gall midge

Record the number of egg masses from 20 randomly chosen hills across each

field .Results are better if more hills are sampled therefore adjacent fields can be

combined.

13. Emergence cages : Emergence cages at known area are used to trap and count

the emerged adults.

Eg: Red hairy caterpillars, White grub adults

14. Amount of damage: The amount or the degree of damage is taken as an index

in estimating the population fluctuation of a pest.

a) Enter the field at least two ft away from the bund. Select a site with a dimension of 1 sq. mt. randomly. Record insect damage in percentage or population / plant.

Eg: Stem borers, gall midges etc

15. Marking and tagging: A large number of marked or tagged individuals are

released in the field. After some time insects are collected in different places and

observe the marked or tagged insects/animals.

Eg: Large flying insects like butterflies and rodents

***

Ex No: 2 Survey, Methods of Surveillance of crop pe sts and Diseases –II

Different methods are available to monitor crop health. Depending on the type of approach, these methods use various technological procedures. Techniques such as survey, surveillance, vigilance, remote sensing , meteorological data, scanning and sampling procedures are normally used to monitor crop health.

Survey, surveillance and vigilance:

Survey means to view comprehensively and extensively in great detail, while surveillance means a vigilant or a planned watchfulness.

Survey can also be defined as a means of surveillance, to get a comprehensive view on inspection, examination and identification.

Survey can be conducted at fixed growth stages of the crop or after a disease incidence.

Single Point Survey ( Eye ball method of survey): A qualified plant Pathologist traverses through the cropped area , halts at periodic intervals to inspect crop health and record all observations. This method helps to understand the immediate course of action needed to maintain crop health.

Multiple point survey: This is conducted at different crop growth stages and enables to identify major production constraints and predict yields. Such a methodically collected data for a few crop seasons through regular surveys provide necessary information in developing disease management strategies.

Surveys conducted after the disease outbreak assist in quantifying the amount of crop loss.

When survey is conducted repeatedly over the same area to serve as a feed back for adopting control measures, it is called surveillance . Hence surveillance is a constant watch over the disease development. In other words, surveillance helps in watching whether the disease incidence has crossed economic threshold levels or not.

Surveillance is generally conducted during the early stage of disease development.

Vigilance arises as a consequence of suspicion, and therefore, is subjected to a constant watch. Vigilance is generally maintained at the ports of entry against exotic pests / diseases of quarantine importance.

Eg: National level vigilance against Fire blight of Apple, as the disease is absent in India.

Post entry quarantine stipulations are a prt of the vigilance to make sure that no pathogenic organism is left undetected. Even after an exotic disease gains entry, if detected early, an eradication campaign is conducted, affected area is cordoned off and a strict vigil is maintained to eradicate the organism.

Eg: The vigil maintained on the wart disease of potato in the Darjeeling area in West Bengal.

Aerobiological survey: Generally conducted to identify areas where vector populations are less so that healthy seed production can be taken up.

Climatic survey: Weather and climate influence the occurrence and growth of a disease. Once a relationship is established between these parameters, disease forecasts can be made either through linear or simulation modelsby continuous monitoring of weather.

Eg: Based on scanning continuously recorded weather data, adequate warnings for an application of fungicide are issued to apple farmers in Himachal Pradesh for the control of Apple scab caused by Venturia inaequalis.

Remote sensing : Estimating an object without being in physical contact with it is remote sensing. Remote sensing is used to locate unhealthy coconut trees in Kerala state.

Sampling procedures :

Collection and analysis of large number of samples is expensive. Hence, it is necessary to develop an appropriate sampling methodology for selecting samples that would give estimates of the parameter under study within a specified degree of possible error.

Sample can be defined as a set of units or proportion of an aggregate of the material which has been selected in the belief that it will be representative of whole population. Generally, a pilot survey is conducted to test and verify the survey methods before adopting it on a large scale.

In Plant Pathology, a sample size of 24.3 m2 leaving border rows is considered for reliable estimates of crop loss and yield.

Varied disease incidence and disease aggregation affect sampling techniques.

Each field may be sampled with five sampling design s – left and right diagonal; left and right W, and stratified random s ampling. (Fig1)

Of all the sampling methodologies stratified random sampling requires least number of samples and the lowest sample intensity to estimate disease incidence within a 95% confidence interval.

--- ----

Ex No: 3 Steps in Pest and disease diagnosis in the field- 1. Pests

Insect and non insect pests cause a particular type of damage to the plant parts often characteristic to particular pests

The pest mostly insect not present on the site of damage makes it difficult to know the casual organism. Sometimes , the symptoms of damage caused by insects may closely resemble to those resulted due to pathogens or due to nutritional disorders. So, practical experience makes familiar about the correct diagnosis on the basis of visual symptoms of damage to take appropriate control measures .

Root and Tuber Damage

Root Damage

1. Wilting and Drying of plants in patches.

Leaves of affected plants turn pale, droop down and ultimately wither off.

Cut end of affected stem of collapsed plant swells, a characterstic diagnostic symptom.

Eg: root grub Holotrichia spp , Anomala spp

2. Tillering is poor, Affected plant turns yellow and stunted

Eg: Rice root weevil

3 .Tunnels on pseudostem and plants break down at tunneled portion

Plants bear few fruits and suckers

Circular holes with black rotten tissue of rhizome plugged with excreta

Eg: Banana Rhizome weevil

4 .Wilting and death of plants in Sorghum

Damaged tubers in potato

Eg: Termites

4. Wilting and Drying of plants and presence of large number of ants at the base of ragi tillers

Eg: Ragi root aphid

5. Root knots

The tomato roots show knots

Eg: Root knot nematode, Meloidogyne incognita

Tuber Damage

1. Potato tubers: with holes and tunnels inside

Eg: Potato tuber moth, Pthormia operculella and poatato white grubs

2. Sweet potato tuber: with holes

Eg :Sweet potato weevil , Cylas formicarius

TREE DAMAGE:

Yellowing of trees, withering of leaves, drying of twigs or complete drying of tree. Some times gummy material oozes from the affected portion on the tree trunk

Eg: Tree borers of mango, cashew, coconut red palm weevil

BARK DAMAGE

Galleries of frassy web on the stem and near bark/angles of branches, Silken ribbon plastered on stem

Eg: Bark eating caterpillars of citrus, mango, guava, casuarina and jack

STEM DAMAGE

1. Damaged part is cut off from the main plant and affected part wilts,dries up and exhibits symptoms like dead heart/white ear/bunchy top

Eg: Stem borers of paddy,millets,sugarcane and brinjal etc

2. a) Bored hole on stem at or just below the ground level, Mature and developing pods are filled with mud in Groundnut

b) Earthen sheeting at the base of plant, mud filled galleries in shoots, drying of shoots in Sugarcane

c) Mud galleries on tree trunk, if earthen sheet is removed eaten bark of trees is visible, Death of young plants and dry up in Mango

d) Mud galleries on tree trunk, bark and stem are eaten below the mud galleries, Nursery and transplanted fields show wilting of central shoot and stunted growth in coconut

Eg: Termites, Odontotermes obesus

3. Ringing and girdling of stem bark

Eg: Grape vine stem girdler, Sthenias grisator

Amaranthus stem weevil ,Hypolixus truncatulus ,

Coccinia gall fly , Neolasioptera cephalandrae

4. Galls on stem :

Eg: Tobacco stem borer, cotton stem weevil

SHOOT DAMAGE :

1 .Wilting ,drooping of terminal plant part whcih later dries up

Eg: Shoot borers of brinjal, bhendi,cotton,castor, shoot fly of sorghum and blackgram stem fly.

LEAF DAMAGE

Mines in leaf

Insect larval stages cause different types of mines infesting between epidermal layers

Serpentine mines: Thread like Eg: American serpentine leaf miner, Liriomyza trifoli

Linear or serpentine mines: Thread likeEg: Citrus leaf miner, Phyllocnistis citrella

Blotch mines: Blight Eg:Patch like.Blotch leaf miner, Acrocercops syngramma

Punctures on leaf

Leaves show punctures made by insects for feeding or oviposition Eg: Bean flies Ophiomyia phaseoli

Galls on leaf

Due to insect feeding on the leaves, the plant reaction results in gall formation like warts, etc Eg: Mango gallfly, Procantarina mattesiana

Out growths on leaves:The damage makes the plant to produce felt lie out growths Eg: Jasmine mite, Aceria jasmini

Shelter feeding

Leaf rolling/folding: Single leaf is folded to create shelter for feeding or pupation Eg: Rice case worm, Nymphula depunctalis

Leaf webbing

Few leaves are webbed together and the larva feeds in between the leaves by scraping Eg: Pumpkin caterpillar, Diaphania indica.

Terminal leaf webbing

The terminal tender leaves are webbed together and larvae and pupal stages occur in the webbed leaves. Larvae feed by scraping the surface. Eg: Sapota leaf webber, Nephopteryx eugraphilla

Leaf feeding

Scraping : Early instar larvae feed by scraping the surface of leaves leaving papery patches. Eg: Larvae of Spodoptera litura

Papery windows: Ladder like papery windows caused by the feeding of adult beetles.Eg: Brinjal Epilachna beetle, Henosepilachna vigintioctopunctata

Holes

Small round holes result due to the feeding of small adult beetles on leaves Eg: White spotted flea beetle, Monolepta signata

Medium round symmetrical holes on leaves by the larval stages Eg: Peanut defoliator Helicoverpa armigera

Irregular bigger holes on the leaves caused by the larval stages of many lepidopteran insects Eg: Slug caterpillar, Latoia lepida, Hairy caterpillar, Euproctis fraterna

Skeleenization of leaves by completely feeding on leaf lamina, leaving only the veins by larval stages Eg: Castor semilooper, Achoea janata

Free feeding . Completely the lamina and veins eaten away by the voracious feeder or in severe cases by the larvae Eg: Lemon butterfly, Papilio demoleus.

Nibbling: The leaves from margins in to small U shaped cuttings is done by adult beetles Eg: Grey weevil, Myllocerus viridanus

Cutting the leaves in to big semi circular shape is done by adult bees

Eg: Leaf cutting bee, Megachile anthracina

Crinkled leaves are due to sucking of cell sap by ymphs and adut insects Eg: Aphids

Cupping /curling of leaves with result due to sucking of insects

Eg: Thrips

FRUIT DAMAGE

Spots on outer surface indicate the oviposition punctures of insects on fruits

Eg: Mango fruit fly, Bactocera dorsalis, Ber fruit fly, Carpomyia vesuviana and cucurbit fruit fly Bactocera cucurbitae

Corky layer on fruit surface is caused by laceration of cells

Eg: Grape vine thrips , Rhipiphorothrips cruentatus

Bore holes plugged with excreta on the fruits are done by larvae

Eg: Bhendi shoot and fruit borer, Earias vittella

Bore holes without excreta and sometimes, larva is seen outside

Eg: Tomato fruit borer, Helicoverpa armigera

SEED DAMAGE: (STORED GRAIN PESTS)

Webbed food items/stored seeds

Eg: Rice weevil,red rust flour beetle,rice moth

GRAIN DAMAGE:

Shriveled or chaffy grains during reproductive stage of the crop

Eg:Rice gundhy bug, sorghum ear head bug, sorghum midge

DIAGNOSIS BY LOCATING SIGNS ON/NEAR PLANTS

Diagnosis by locating signs:

Black ants, Componotus compressus movement on plant parts

Honey dew secretion on plant parts:

Sooty mould development on plant parts:

All the above indicate the presence of Homopteran insects Eg: Mealy bug Planococcus lilacenus, Aphid , Aphis craccivora, Whitefly, Bemisia tabaci

Excreta of Insects:

Black spots are found due to drying of excreta on leaves by thrips

Presence of excreta indicate usually the lepidopteran larvae

Scale covering:

The stem , leaves etc are covered heavily by the scale covering

Exuviae of insects:

Moulted skins of leafhoppers , aphids etc present usually on lower surface of leaves

BPH moulted skins at base of plant and floating in water

Steps in Pest and diseases diagnosis in the f ield- 2. DISEASES

In the field symptoms due to different biotic and abiotic causes overlap several

times. Hence it is necessary to distinguish the affects of abiotic and biotic causes in the field so that correct diagnosis can be made.

A) SYMPTOMS - plant reactions or alterations of a plant’s appearance due to a

disease or disorder

1. Identify and classify symptoms � Underdevelopment � Overdevelopment � Necrosis or death � Alteration of normal appearance � Wilting

2. Identify plant parts affected i) Underdevelopment

Stunting of plants, leaves Shortened internodes Inadequate chlorophyll production

Diagnosis: Caused by many types of biotic / abiotic causes ii) Over-development a) Biotic causes Root knot nematodes - root galls Callus formation around cankers Tissue proliferation -some downy mildews and phytoplasmas Some insects and mites also cause galls. b) Abiotic causes Oedema - an abnormal swelling in a plant caused by a large mass of parenchyma or an accumulation of water in the tissues leading to

Tannish-brown, corky or scabby appearance to leaves. The problem is favoured by high humidity, cloudy weather, poor soil drainage, and

excessive watering. Fasciation (Malformation of plant parts resulting from disorganized tissue growth) can be physiological or due to biotic cause.

iii) Tissue Necrosis: a) Fungal leaf spots � Usually round, not vein-limited � Elongated on narrow leaves or stems � May have alternating zones of light and dark tissue � Sporulation or mycelia may be evident b) Bacterial leaf spots � Often dark and water-soaked � Often vein-limited, giving angular shape � Bacterial “flow” observed under microscope c) Fruit rots

� Firm or soft and watery � Colors vary � Fungal sporulation may be present � Fungal and bacterial causes d) Cankers = localized necrotic lesions � Sunken or swollen or both � Mainly caused by fungi and bacteria � Mechanical injury can cause e) Blight = rapid death or dieback. � Also from coalescing leaf spots, e.g. early blight of tomato � Mainly fungal and bacterial causes f) Dieback - many causes � Girdling cankers. � Root problems � Mechanical, chemical or cold damage g) Root rots � Root lesions � Darkening and softening of roots � Sloughing off of outer tissues � Yellowing of foliage and stunting of plants � Fungal and bacterial causes h) Damping off � Rapid death of seedlings and cuttings � Stem infected at soil line, seedling topples � Spreads rapidly under crowded conditions � Mainly fungal agents i) Wilting Biotic factors � Root, crown or stem rots � Vascular wilts � Root, crown or stem damage from insects or animals � Mainly fungal and bacterial causes Abiotic factors � Damage from weather extremes � Dry or flooded soil � Mechanical damage to roots, crown or stem j) Alteration of normal appearance Mosaic � Irregular patches of discolored tissue. � Often with distortion � Viruses mainly Ringspot � On leaves and fruits. � Distinct ring shaped lesions, often in concentric zones � Viruses Abiotic causes � Chemical damage � Nutritional deficiencies Yellowing � Often nutritional, cultural or environmental � Root malfunction – biotic or abiotic � Nematode infestation

� “Yellows” phytoplasma diseases � Be aware of symptom variability. � May have more than one problem. � More than one pathogen may be involved. � Pathogens have varying levels of virulence. � Environmental conditions can affect symptom expression. � Host genetics and physiology can effect symptom expression. B) SIGNS: Signs - actual pathogen, parts or by-products seen on a diseased

host plant Fungal signs � Evidence of pathogen on tissue. � Spores, mycelia or fruiting bodies. � Use hand lens or knife for field detection. Fruiting bodies � Shape of fruiting body aids in fungal identification. � Tissue location may help differentiate between species. Powdery mildew fungi � Powdery mildew fungi form mycelia and spores on tissue surface. � Powdery material rubs off. � Leaves often distorted, discolored � Dark, round fruiting bodies form in fall. Downy mildew fungi � Downy mildews often produce angular leaf spots on upper surface of leaf � Downy mildews develop sporulation on leaf undersides only. Bacterial signs � “Streaming” from freshly cut stem in water. � Bacteria “flow” observed from tissue mount on compound microscope. Bacterial ooze can be observed on-site with some diseases. Distribution of symptoms on plant parts: � Biotic disease – symptoms progress and nearby plants become infected. � Abiotic disease – generally a lack of symptom progression. Does not

spread. Exception – nutritional symptoms progress slowly. Pattern of symptom development � Determine prevalence of problem: Large area/All plants – generally abiotic � Scattered, localized – generally biotic � Check for distribution of symptoms • Uniform – generally abiotic Random – generally biotic B) Questions to be asked: � When was the problem noticed? � Was the damage sudden or gradual? � How old are affected plants? � Percentage of plants affected? � What is the degree of injury? Review cultural practices. � Proper planting technique � Fertilizer and pesticide application � Irrigation frequency Review environmental conditions. � Temperature extremes � Drought or excess rain

� Soil type and conditions Check host specificity – many hosts may mean an abiotic problem C. Laboratory Examination and Testing � Compound microscope � Electron microscope � Moist chamber incubation � Culturing � Additional tests for biotic agents � Tests for abiotic agents LaboratoryExamination: Examination using microscope of higher magnificatio n � Identify fungi to genus or to species. � View bacterial flow; observe morphology at highest magnification. � View virus inclusion bodies. � Using electron microscope, view viruses, phytoplasmas Moist Incubation � Goal – to induce sporulation � Important for obligate fungal pathogens � Avoid excess moist conditions. Fungal isolation � Surface sterilize. � Use margin of diseased area. � PDA media, can be selective � Diagnostician can often identify to genus from appearance of culture Fungal identification – Other methods � Examination and comparison with drawings in literature � Utilizing keys in literature � Literature sources for host diseases and disorders � Serological, molecular, other tests Bacterial isolations � Grind tissue in sterile water. � Streak suspension on bacterial medium. � Can use selective media � Transfer single, isolated colony Bacterial identification �Ooze test �Biochemical tests �Carbohydrate utilization (BIOLOG) �Fatty acid methyl ester analysis (FAME) �Molecular methods �Polymerase chain reaction (PCR) � Serological tests, e.g. ELISA Identification of other pathogens : Non-culturable pathogens � Viruses, viroids � Phytoplasmas � Fastidious bacteria Methods � Serological tests, e.g. ELISA � Electron microscopy � Staining for virus-induced inclusion bodies � Molecular tests, e.g. PCR � Enzyme activity testing

� Host range testing Identification of Nematodes i) Extraction from Soil and Plant Material � Soil extraction using centrifugal flotation � Baerman funnel techniques for soil and tissue � Mist chamber extraction for nematodes in root or stem tissue ii) Direct examination of nematodes in tissue Diagnostic tests for abiotic causes i. Soil, water � pH testing � Nutrient analysis � Soluble salts analysis � Analysis for chemicals ii. Plant tissue tests � Nutrient analysis � Analysis for chemicals Investigate pathogenicity i. Is identified organism a known pathogen - of host? - of hosts in same genus? ii. If not a host, Koch’s Postulates may be next st ep � A lengthy process, rarely used in routine diagnoses � Problem arises when organism cannot be cultured iii. Koch’s Postulates 1. Note constant association of organism with diseased plants and consistent

observable symptoms. 2. Isolate and characterize organism in pure culture. 3. Inoculate healthy plant with organism, and observe the same disease and

symptoms. 4. Re-isolate same organism. Final Diagnosis: All information compiled and analyzed Organism identified, found to be pathogen of host OR Lab tests, other information reveal an abiotic cause Develop control recommendations and present to farm er.

Ex No: 4 Agro Ecosystem Analysis (AESA) , Pest: Def ender ratio adopted in farmers field school

AESA is an approach which can be gainfully employed by extension functionaries and farmers to analyse field situations with regard to pests, defenders (Natural enemies), soil conditions.Plant health, the influence of climatic factors and their interrelationship for growing healthy crop. Such a critical anlysis of the field situations will help in taking appropriate decision on management practices.

The basic components of AESA are

1. Plant health at different stages (Phenophases)

2. Built-in compensation abilities of the plants

3. Pest and defender population dynamics

4. Soil conditions and edaphic factors

5. Climatic factors temperature,RH,raifall,etc

6. Farmers experience of pest,diseases and weedsetc.

Methodology:

A.Field observations :

a) Enter the field at least two ft away from the bund. Select a site with a dimension of 1 sq.mt.randomly.

b) Record the visual observations in following sequences:

i) Flying insects(both pests and defenders)

ii) Close observation on pests and defenders which remain on the plants

iii) Record diseases and its intensity

iv) Record insect damagein percentage or population/plant

c) Record parameters like number of leaves ,branches ,plant height and reproductive parts of the selected plants which should be flagged for making observation in the following weeks.

d) Record the types of weeds, their sizeand population density in relation to crop plant.

e) Record soil conditionsviz.flooded,wet or dry.

f) Observe rodent live burrows

g) Repeat the step(a to f) in four sites randomly selected

h) Record the climatic factor viz sunny,partially sunny,cloudy,rainyetc for the preceding week

B.Drawings:

First draw the plant with actual number of branches/leaves etc at the centre on a chart.Then draw pests on left side and defender on the right side. Indicate the soil condition,weed population,rodent damageetc.Give natural colour to all the drawing , for instance ,draw healthy plant with green colour ,diseased plant /leaves with yellow colour ,while drawing the pests and the defenders on the chart care should be taken to draw them at appropriate part of the plant, where they are seen at the time of observation.The common name of the pest and defenders and their population count should also be given along with diagram.The weather factor should be reflected inthe chart by drawing the diagram of sun just above the plant if the attribute is sunny.If clouds may be drawn in place of sun.In the case of partially sunny, the diagram of sun may be half marked with clouds.

C.Group Discussion and Decision making:

The observations recorded in the previous and current charts should be discussed among the farmers by raising questions relating to change in pest and defender population in relation to crop stages, soil conditions,weather factors such as rainy,cloudy or sunny,etc .The group may evolve a strategy based upon weekly AESA,ETL and corresponding change in P:D ratio and take judicious for specific pest management practices

D.Strategy for decision making (Examples):

Some of the defenders like lady beetles ,syrphids play useful role in arriving at P:D ratio

Eg: In case of BPH in Paddy, P:D ratio is 1:4 here pest is BPH and Defender is Mirid Bug, if P:D ratio is 1:4 there is no need for insecticidal spray, since the predators can take care of the pest.

ExNo 5: Field diagnosis of important insect pests and disea ses of cereals and millet crops

Important insect pests of cereals and millet crops

Paddy

I.Sucking Pests

1. BROWN PLANTHOPPER Nilaparvata lugens

Symptoms:

� Premature yellowing of leaves and drying of plants in isolated circular patches

� Drying of plants spreads in a circular fashion

� Sooty mould

� Exuviae at the base of plants

� Affected stems turn soft and are unfit for use as straw

2. RICE GREEN LEAFHOPPER Nephotettix nigropictus, N.virescens

Symptoms:

� Yellowing, stunting and withering of plants

� Leaves turning brown with small scratch like marks on leaf in severe infestation

� Uniform yellowing from mid half of leaf

3. RICE EARHEAD BUG/GUNDHI BUG Leptocorisa oratorius

Symptoms:

� Affected grains become shrivelled and chaffy

� Brown spot is observed at the feeding site where sooty mould develops

� Lower grain quality and broken grains when infested at soft dough stage

4. PADDY LEAF MITE / YELLOW MITE, Oligonychus oryzae

Symptoms:

Pale whitish blotches on upper side of leaf which later turn yellow to orange colour.

Thin webs are seen on the under surface of leaves.

5. PANICLE MITE / SHEATH MITE, Steneotarsonemus spinki

Symptoms:

Brown necrotic patches on midribs of leaves.

� Brown necrotic lesions on leaf sheath.

� Sterile and discoloured grains in the panicle.

� Grains turn black.

II.Borers:

1. Paddy stem borer Scirpophaga incertulas

Symptoms:

� “Dead-heart” at vegetative stage which turns brownish, curls and dries off

� “White ears” at heading stage with empty, partially filled grains

� Presence of egg masses near the tips of tender leaf blades

� Activity of moths in the vicinity

� Frass at the feeding site

2. RICE GALL MIDGE Orseolia oryzae

Symptoms:

� Hollow whitish to pale green cylindrical tube in tillers known as gall / silver

shoot/onion shoot bearing at its tip a green, reduced leaf blade complete with

ligules and auricles.

� Vigorous subsidiary tillering if infested in early growth period

Infested tillers do not bear panicles.

III Defoliators

1. RICE LEAF FOLDER , Cnaphalocrocis medinalis

Symptoms:

� Whitish membranous folded leaves with typical white streaks

� Faecal pellets when leaf opened

� Reduced vigour of the plant

2. RICE HISPA , Dicladispa armigera

Symptoms:

� Whitish leaf tips of young leaves giving dried up appearance

� White, rectangular streaks parallel to veins on older leaves, which initially appear

glistening, membranous, papery white, later turning pale reddish, straw coloured

� Blister spots towards leaf tip

3 .GRASSHOPPERS Rice large grasshopper : Hieroglyphus banian

Rice small grass hopper : Oxya nitidula,

Symptoms:

Irregularly cut leaf margins. In severe cases only midribs and stalks remain.

Gnawing at the base of the panicle at heading stage.

4. RICE SWARMING CATERPILLAR Spodoptera mauritia

Symptoms:

Seedlings in the nursery are reduced to mere stumps due to voraceous feeding .

5. CLIMBING CUTWORM Mythimna separata

Symptoms:

Cut earheads seen floating in water

Defoliation.

6. RICE CASEWORM, Paraponyx stagnalis

Symptoms:

Tubular cases seen hanging from lower surface of leaf blade

7. RICE WHORL MAGGOT, Hydrellia philippina

Symptoms:

Narrow stripes of whitish area in the blade margins.

Boot leaf and spikelets are damaged . Shrivelling of spikelets.

IV Root Feeders

1. RICE ROOT WEEVIL, Ehinocnemus oryzae

Symptoms:

Poor tillering and stunted growth of plants seen in isolated patches.

SORGHUM

I.Borers:

1. SORGHUM SHOOTFLY, Atherigona soccata

Symptoms:

� Dead heart which can easily be pulled out giving offensive smell at cut end

� Production of side/secondary tillers which are in turn attacked.

2. SORGHUM STEM BORER , Chilo partellus

Symptoms:

� Shot holes due to biting across leaf spindle

� Dead heart with no offensive smell at cut end when pulled out

� Chaffy earheads in later stages

3. RAGI PINK BORER Sesamia inferens

Symptoms:

� Dead hearts

� Chaffy earheads later

II. Sap Feeders:

1. SORGHUM MIDGE ,Stenodiplosis sorghicola

Symptoms:

� Red ooze from spikelet when squeezed indicating the presence of maggot

� Chaffy grains with round holes indicating fly emergence

� Empty pupal cases protruding from glumes

2. SORGHUM EARHEAD BUG, Calocoris angustatus

Symptoms:

� Shrivelled, unfilled, chaffy grains which initially show red spots on feeding sites

and later turn black

� Whole earhead turn black and later dries up.

3. SORGHUM APHID / CORN APHID ,Rhopalosiphum maidis

Symptoms:

Mottled appearance of tender ear heads with yellow patches,

Failure of grains to develop in ear head

Sooty mould on the plants.

4. MAIZE SHOOT BUG , Peregrinus maidis

Symptoms:

Yellowing of foliage, stunted growth and scorched appearance.

Presence of ants, Camponotus compressus, Monomorium destructor on honeydew

Sooty mould on plant

5. RAGI ROOT APHID , Tetraneura nigriabdominalis

Symptoms:

Gradual fading and drying up of plants.

Activities of ants at collar region of plant for honeydew

Collar region turns black.

III. Leaf Feeders/Defoliators:

1. FLEA BEETLE, Chaetocnema pusaensis, Longitarsus sp.

Symptoms:

Smallb holes on leaves.

2. DECCAN WINGLESS GRASSHOPPER, Colemania sphenerioides

Symptoms:

Irregularly cut leaf margins

Devoured flowers and ripening ears

3. RED HAIRY CATERPILLAR, Amsacta albistriga, A. Moorei

Symptoms:

� Heavy defoliation

� Entire crop looks as though grazed by cattle

4. RAGI CUTWORM ,Spodoptera exigua

Symptoms:

Extensive defoliation.

5. ARMY WORMS / CUTWORMS, Agrotis basiconica, A. flammatra, A.ipsilon, A.spinifera

Mythimna separata

Symptoms:

Heavy defoliation

Cut tender stems of young and growing plants

In severe cases, entire leaf is eaten. The field looks as if grazed by cattle.

IV. Infloresence Feeders:

1. RED HAIRY CATERPILLAR , Amsacta albistriga, A. Moorei

Symptoms:

� Heavy defoliation

� Entire crop looks as though grazed by cattle

2. BLISTER BEETLES

Orange banded blister beetle : Mylabris pustulata

Brown blister beetle : Gnathospastoides rouxi

Symptoms:

Damaged Flower petals and pollen

Poor grain set.

Damaged tender foliage.

Important diseases of cereals and millet crops

1. Diseases of Rice

Symptoms visible on

A. Leaves & leaf sheath B. Nodes and culm C. Flower or panicle

A. Symptoms seen on leaves and leaf sheath

1. Yellowing of leaves with rusty specks at tip associated with stunted growth of plants

in patches

a) Iodine test - i) Positive - Rice tungro

ii) Negative - Deficiency of zinc (?)

Spraying Zn So4 corrected yellowing – Zn deficiency (Khaira

disease)

2. Localised necrotic spots on leaves

a) Spindle shaped spots with dark margin, grayish center and yellow halo – blast

b) Circular to oval spots with white or grayish center – brown spot

c) Narrow brown coloured spots without grayish center – narrow brown leaf spot

d) Irregular Spots, spreading in nature with greenish grey center, cover entire leaf

sheath and leaves, appear as ornamentations of scales on a snake – sheath blight

e) Symptoms appear only on boot leaf sheath. Irregularly spreading necrosis on

boot leaf sheath with grayish center – Sheath rot

f) Leaf tip drying, yellowing proceeds from tip downwards in wavy manner, later

straw coloured portions in place of yellowing, appearance of ooze – Bacterial leaf

blight

g) Yellow linear transluscent streaks which later dry and appear as necrotic streaks

– Bacterial leaf streak

3. Symptoms on nodes and culm

a) Necrosis at the basal portion of the culm just above water line

a’) death of culm and profuse tillering, associated with black minute sclerotial

bodies – stem rot

b’) No death of culm, symptoms spreading on to the leaf sheath and leaves –

sheath blight (2d)

b) Necrosis at nodes – nodes break off – blast

4. Symptoms on flowers and panicle

a) White ear - a’) panicles can be pulled off easily – stem borer

b’) peduncle contains necrotic spot and breaks off at the point

of infection - blast

b) Brown coloured grains - a’) Necrosis on boot leaf sheath and majority grains

converted in to chocolate brown coloured grains –

sheath rot

b’) No necrosis on boot leaf sheath

- individual grains discoloured – mites

- partial or full conversion of grains with half

chaffy and remaining half brown – bugs

c) Individual grains are replaced by yellow to green spore balls – False smut

****

2. Diseases of Sorghum / Jowar

Part of the plant affected: A. Whole plant B. Part of the plant

A. Whole plant -

a’) No stunting of plants and wilting in the afternoon only

Plants restored after irrigation - water stress

a’’) Stunting of plants and plants restored after irrigation

Plants surrounded by small plants with blue to white flowers - Striga

a’’’) Sudden wilting, did not recover after irrigation, plants lodge, roots

disintegrated, cut open stem shows thread like vascular bundles

associated with black powdery microsclerotia, generally seen after

flower initiation – charcoal rot

B. Part of the plant

b’) Symptoms on leaf: 1) Initially red coloured rectangular spots. Later produce

dot like acervuli at the center of the spot -

Anthracnose or red leaf spot

2) Small to extended / elongated spots with dark margin

and grayish center - Turcicum Leaf blight

3) Orange to brown coloured rusty powdery mass on

leaves – Rust

4) Chlorotic or yellow streaks on the upper surface,

downy growth on the under surface (during early

hours of the day), yellowing of top leaves, leaf

shredding, barren ear heads - downy mildew

b’’) Symptoms on stem 1) red coloured spots associated with acervuli, internal

portions of stem show red colour – anthracnose / red

rot

b’’’) Symptoms on flowers 1) At the time of flowering

i) Sugary secretions / ergot bodies noticed

– sugary disease or ergot disease

ii) Whole ear head converted in to black

powdery mass - Head smut

iii) Individual grain converted in to black

powdery mass, covered by a delicate

white membrane with central spine like

black columellum – covered smut

2) After grain maturity – grains discoloured or turn black,

mouldy growth on the grains, generally after rains at

the time of harvest. - grain moulds.

3. Diseases of Bajra / Pearl millet

Part of the plant affected: A. Leaf B. Ear head

A. Symptoms on leaf:

a’) Chlorotic or yellow streaks on the upper surface, downy growth on the

under surface (during early hours of the day), yellowing of top leaves, green

ear formation - downy mildew

a’’) Orange to brown coloured rusty powdery mass on leaves – Rust

B. Symptoms on flowers / ear head

b’) Sugary secretions / ergot bodies noticed – sugary disease or ergot disease

b’’) Individual grain converted in to black powdery mass, covered by a

delicate white membrane without columellum – smut

4. Diseases of Ragi / Finger millet

Part of the plant affected: A. L eaf B. Node C. Ear head

A. Symptoms on leaf:

a’) Spindle shaped spots with dark margin and grayish center, surounded

by yellow halo - Blast

a’’) Yellowing, mosaic streaks, sterility of the plant – Mosaic virus disease

B. Symptoms on Node:

Necrotic lesion on node, node breaks off easily – Blast

C. Symptoms on ear head

c’) Necrotic lesion on peduncle of fingers, peducle breaks at the point of

infection – Blast (Finger blast)

c’’) Individual grain converted to smut sorus, no columellum - Smut

5. Diseases of Maize / Corn

Part of the plant affected: A. L eaf / leaf sheath B. Stalk C. Cob

A. Symptoms on leaf / leaf sheath

a’) Small circular brown spots which later elongate and turn elliptical covering

large portions of the leaf - Turcicum leaf blight.

a’’) Small circular necrotic brown spot initially on the lower most leaf sheath,

spreads upwards with irregular margin and greenish white center (bands of

brown necrotic lesions). Sclerotial bodies are seen on the infected portion.

Infects even cobs and cause brownish discolouration with poor grain set –

Banded leaf and sheath blight

a’’’) Chlorotic or yellow streaks on the upper surface, downy growth on the

under surface during early hours of the day, complete yellowing of young

leaves, appearance of young leaves failed to open properly, leaf shredding –

sorghum downy mildew

Crazy top (malformation of tassel in to green leaf like structures – crazy top

downy mildew

B. Symptoms on stalk:

BB) Preflowering

b’) Wilting of the plant in seedling stage under excess soil moisture conditions –

Pythium pre flowering stalk rot

b’’) Wilting of plants in seedling stage with dark black minute dot like pycnidia

formed inside stalk – Diplodia Pre flowering stalk rot

BBB) Post flowering

b’) Appear under dry conditions, plant suddenly wilts and die, inside stem

appearance of thread like vascular bundles coated with black powdery mass

(microsclerotia)

b’’) Plants suddenly wilt and die, appearance of reddish discolouration in side

stem, whitish mouldy growth, more common in alkaline soils –

Cephalosporium maydis wilt

b’’’) Plants suddenly wilt and die, purplish leaves, appearance of black

discolouration in side stem, whitish mouldy growth, more common in alkaline

soils – Cephalosporium acremonium wilt

C. Symptoms on cob:

Appearance of brown necrotic bands associated with brown sclerotial bodies –

banded leaf and sheath blight

ExNo 6: Field diagnosis of important insect pests and disea ses of oilseed crops

CASTOR SEMILOOPER Achaea janata, Paralel l ia algira

Symptoms:

���� Defoliated leaves,

���� in severe cases only mid r ib and veins of the leaves

CASTOR SHOOT AND CAPSULE BORER Conogethis punctiferal is

Symptoms :

���� Frassy matter at the bored shoots

���� Webbed seed capsules covered with dark excreta.

TOBACCO CATERPILLAR Spodoptera litura Symptoms:

���� Irregular holes on leaves initially and later skeletonisation leaving only veins and

petioles

���� Heavy defoliation.

���� Presence of bored bolls.

LEAF HOPPERS Amrasca biguttula biguttula

Symptoms:

Margins of leaf turn pale initially, later become yellowish – hopperburn

Drying of leaves and showing brown necrotic patches in severe cases.

Plants lose vigor and yield is affected.

CASTOR BUTTERFLY/ SPINY CATERPILLAR Ergolis merione

Symptoms:

Scraping of chlorophyll on the upper surface of leaves .

CASTOR WHITEFLY Trialeurodes rara, Trialeurodes ricini

Symptoms:

Yellowing and drying of leaves

CASTOR THRIPS Retithrips syriacus, Scirtothrips dorsalis

Symptoms:

The plant loses its vitality.

Terminal leaves turn crinkled and silvery white.

CASTOR SLUG Latoia (Parasa) lepida

Symptoms:

Leaves only with mid r ib and veins.

MITE Eutetranychus sp., Tetranychus telarius

Symptoms:

White blotches on the upper surface of leaves.

PESTS OF GROUNDNUT

WHITE GRUB OR ROOT GRUB Holotrichia consanguinea, H. Serrata

Symptoms:

���� In case of severe infestation the patches of dead plants are seen in the

infested fields.

���� The cut end of the attacked stem of a dead groundnut plant is swollen.

GROUNDNUT LEAF MINER Aproaerema modicella

Symptoms:

���� Mining of larvae in the upper epidermis of leaves which causes in characteristic

blotches

���� Folded leaves.

���� Drying of affected leaves and withering of plants.

���� Severly infested field looks as if burnt from a distance.

RED HAIRY CATERPILLAR Amsacta albistr iga, Amsacta moorei

Symptoms:

Heavy defoliation leaving behind the petiole and mid ribs of leaves and the

main stem of plants

LEAF EATING CATERPILLARS Spodoptera l itura,

Helicoverpa armigera

Symptoms:

Extensive defoliation.

LEAFHOPPER : Empoasca kerri

Symptoms:

Whitening of veins and chlorotic patches at tips of leaflets in a typical ‘V’ –

shape. There will be hopperburn in severe cases.

THRIPS Caliothrips indicus, Scirtothrips dorsalis

Symptoms:

Infested leaves show pale white patches and curling of tender leaflets.

GROUNDNUT APHID Aphis craccivora

Symptoms:

The leaves to curl and stunted growth.

Flowers and pods are also affected.

Excrete honeydew on which sooty mould develops which interferes with

photosynthetic activity of plants.

GROUNDNUT POD BUG Elasmolomus sordidus

Symptoms:

The seeds get shrivelled and become rancid and give bitter taste.

The oil content and germination percentage of infested seed is also adversely

affected.

Besides causing damage in the field, it continues to infest the pods in

threshing yard and even in storage.

JEWEL BETLE Sphenoptera perotetti

Symptoms:

Drying and death of plants.

When examined grub or pupa can be seen in hollowed stem.

PESTS OF SESAMUM

GINGELLY LEAF AND POD BORER Antigastra catalaunalis

Symptoms:

���� Webbed leaves at top with young caterpillars

���� Bored shoots, flower buds and pods

GALL FLY Asphondylia sesami

Symptoms:

���� Malformation of pod without proper setting of seeds.

���� Galled buds and flowers fade and dry.

SPHINX CATERPILLAR/ GINGELLY HAWK MOTH / DEATH’S HE AD MOTH

Acherontia styx

Symptoms:

Caterpil lar feeds on the leaves and acts as a defoliator.

PESTS OF SAFFLOWER

SAFFLOWER APHID Dactynotus carthami

Symptoms:

���� Sooty mould develops

���� Plants become stunted and weak.

���� Heads of both nymphs and adults on the stem are oriented toward soil.

LEAF EATING CATERPILLARS

Prospalta capensis (Saff lower caterpi l lar)

Spodoptera exigua

Helicoverpa armigera

Symptoms:

Extensive defoliation.

PESTS OF MUSTARD

MUSTARD APHID Lipaphis erysmi

Symptoms:

���� Curling and distortion of leaves.

���� Sooty mould

���� Sickly and blighted appearance of leaves.

MUSTARD SAWFLY Athalia lugens proxima

Symptoms:

���� Skeletonisation of leaves

���� Heavy defoliation

���� On sligtest touch, larva falls to ground feigning death.

DIAMOND BACK MOTH Plutella xylostella

Symptoms:

Holes on leaves

���� Skeletonised leaves on affected plants

���� Withered appearance of leaves

PAINTED BUG Bagrada cruciferarum

Symptoms:

Wilt ing and loss of vigour of the plant. It also excretes a sort of

resinous material which spoils the pods.

PESTS OF SUNFLOWER

LEAF EATING CATERPILLARS

Spodoptera l itura

Helicoverpa armigera

Symptoms:

Caterpillars eat leaves and soft portions of the stems. H. armigera feeds

on foliage and tender flower heads and developing seeds. In severe cases there will

be Plants without leaves.

LEAFHOPPER Amrasca biguttula biguttula

Symptoms:

Curling of leaves and ult imately hopper burn symptoms.

Leaves dry up and drop down.

BIHAR HAIRY CATERPILLAR Spilarct ia (= Spilosoma) obliqua

Symptoms:

Defoliatoin of the plants

THRIPS Scirtothrips dorsalis Frankliniel la dampfii

Symptoms:

Curling of leaves

PESTS OF COCONUT

COCONUT BLACK HEADED CATERPILLAR Opisina arenosella

Symptoms:

���� Folded leaflets with silken galleries and frass

���� Large scale drying of leaflets

���� In case of severe attack the whole plantation presenting a burnt up appearance

from a distance.

RHINOCEROS BEETLE Oryctes rhinoceros

Symptoms:

A series of holes on the fronds when leaf opens out and fan like cutting

���� Typical ‘V’ shaped clipping/ cuts on mature leaves, in partly damaged crowns

���� Death of the central growing primordium of both young and old plants in severe

attack

���� Damaged palms often becoming infected by fungal rots.

RED PALM WEEVIL Rhynchophorus ferrugineus

Symptoms:

� Yellowing and wilting leaves of inner and middle whorls.

� Presence of circular holes on the stem with brownish black viscous fluid oozing

out from the holes

� Longitudinal splitting of leaf bases and presence of cocoons or adult weevil or

chewed up fibres in leaf axis or at the base of the palm.

���� The sound of feeding by the grub can be heard by keeping the ear on the trunk of

the tree.

SLUG CATERPILLARS Contheyla rotunda

Macroplectra nararia

Latoia lepida

TERMITE Odontotermes obesus

Symptoms:

Wilting of central shoot is a symptom of the attack.

Base of trunk is seen plastered with runways made of soil and fibre.

COCONUT SCALE Aspidiotus destructor

Symptoms:

Leaflets turn yellowish, finally wither and dry up, thus reducing vitality of plant

COCONUT ERIOPHYID MITE Eriophyes guerreronis

Symptoms:

Triangular pale or yellow patches close to perianth initially at the level of perianth

which turn into brown patches with longitudinal fissures and splits on the husk

(warting)

���� Shedding of butons

���� Oozing of the gummy exudation from the affected surface.

���� Reduced nut size and copra content.

���� Malformed nuts with cracks and hardened husk.

III Diseases of oilseed crops

1. Diseases of coconut

Part of the plant affected: A) Stem B) Crown C) Fonds D) Leaves E)

Nuts

A) Stem: 1. Appearance of gummy secdretions from the stem at the

basal portion, formation of cavities in the trunk – Stem

bleeding

2. Appearance of gum from the stem portion, formation of

brackets on the stem and root portions – ganoderma root

rot

B) Crown 1. Crown rots completely, fonds turn yellow and hang on,

severe cases plants turn barren (no leaves only trunk) –

Phytophthora crown rot

C) Fonds 1. Yellowing of older leaves and gummy secretions from stem

– Ganoderma root rot

2. Yellowing of heart leaf or crown leaf – Bud rot

D) Leaves: 1. Appearance of brown coloured circular to oval spots with

dark margin and grayish center associated with dot like

acervuli – Grey blight

E) Nuts : 1. Round shaped nuts, spongy in texture which can be very

easily pressed, poor copra formation – Tatipaka disease

2. Diseases of Groundnut

Part of the plant affected : A) Whole plant B) Leaf / Stem / Peg / Kernel

A) Whole plant affected:

1) Wilting and drying of plants, rotting of collar region, appearance of white

thread like mycelial growth on the affected portion, association of mustard

seed like sclerotial bodies - Sclerotium wilt

2) Wilting and drying of plants, blackened roots, bark of roots peels off easily,

disintegration secondary and tertiary roots, more common in dry conditions –

dry root rot

3) Drying of plants starting from apical portions, necrotic streaks on stem –

Stem necrosis disease

4) Drying of apical portions, proliferation of side shoots, ring spots on leaves –

Bud necrosis virus

5) Stunted plants with dark green foliage, brownish yellow lesions on pegs,

stems, roots and pods – kalahasti malady

6) Death of young plants associated with development of black powdery mass

aound dead portions and dead plants _ Aspergillus niger seedling rot

B) Symptoms on leaf / stem / peg / kernel

1) Small 3-5 mm, round, black spots on leaves with yellow halo – Early leaf spot

2) Small 2-3 mm, round spots on leaves without yellow halo – Late leaf spot

3) Small 1-2 mm black dot like spots on leaves without yellow halo – Pepper leaf

spot

4) Small 1 mm brown rusty specks on under side of the leaf – Rust

5) Black, irregularly spread leaf spots specially at the leaf tip with yellow halo –

Alternaria leaf spot

6) Necrotic lesions on stem and death of plant – Groundnut stem necrosis

7) Necrotic lesions at the apical tip, drying of apical portions – Groundnut Bud

necrosis

3. Diseases of Sesamum

Part of the plant affected : A) Whole plant B) Leaf / Stem / capsule

A) Whole plant affected:

1) Wilting of plant, blackened stem and root portions, root bark peels off,

disintegration of secondary and tertiary roots, prevalent in dry conditions –

dry root rot

2) Flowers modified in to green leaf like structures, sterility of the plant -

Phyllody

B) Symptoms on leaf, stem and capsule

1) Black necrotic lesions with yellow halo associated with grayish center and

concentric zonations, prevalent after flower initiation, black spreading lesions

on stem and capsules – Alternaria leaf blight

2) Black necrotic lesions on leaves and stem with or without yellow halo, no

grayish center, oozing from stem – Bacterial leaf spot and blight

3) Greyish powdery growth either on one side or both the surfaces of the leaf –

powdery mildew

4. Diseases of Castor

Part of the plant affected : A) Whole plant B) Leaf / Stem / capsule

A) Whole plant affected:

1) Wilting of young seedlings, blackened stem and root portions, prevalent in

rainy season under water logged conditions – Phytophthora seedling blight

2) Wilting of the plant, spreading necrotic lesions on stem, inside stem portion

blackened vascular elements – Fusarium wilt

3) Wilting of plant, blackened stem and root portions, root bark peels off,

disintegration of secondary and tertiary roots, prevalent in dry conditions –

dry root rot

B) Symptoms on leaf / stem / capsule

1) Small, circular, 2-3 mm spots with grayish center, several spots on leaf –

Cercospora leaf spot

2) Small, light brown raised pustules on lower leaf surface and yellow spots on

upper surface – Rust

3) Black necrotic angular lesions on the leaf, concentrated around veins, yellow

halo – bacterial leaf spot

4) Spreading, brown necrotic lesions on leaves surrounding raceme, dried

siliqua, grey powdery mouldy growth on the raceme – Grey mould / Grey

blight

5. Diseases of Sunflower

Part of the plant affected : A) Whole plant B) Leaf / Stem / head

A) Whole plant affected:

1) Sickly appearance of the 40 day old plants, withering and wilting followed

by death of the plant.

a) Damping of young seedlings associated with velvety fungal

growth – downy mildew

b) Association of fan like white mycelial growth at collar region

and presence of mustard seed like sclerotial bodies – Sclerotium

collar rot

c) Association of white fluffy cottony white mycelial growth and

presence of elongated black sclerotial bodies – Sclerotinia collar

rot

B) Leaf / stem / head:

i) On leaves:

1) On leaves, black necrotic lesions with yellow halo, spots enlarge and

develop concentric circles with in – Alternaria leaf spot

2) On leaves, small rusty powdery pustules on lower leaf surface, yellow

spots / patches on upper surface, drying of affected leaves – Rust

3) On leaves, white powdery ectoparasitic mycelium, end of the season

powdery growth is associated with black dot like cleistothecia – powdery

mildew

4) On leaves, abnormally thick mid rib, leaves curl downward, yellow angular

spots on upper surface and velvety growth on the under surface (in the

early cool hours of the day) – downy mildew

5) On leaves, mosaic pattern of green and yellow patches – mosaic virus

6) On leaves, small necrotic patches, twisting of the leaf, withering of top

leaves (paralysis) - stem necrosis

ii) On stem:

7) Formation of galls at the basal part of the stem – Downy mildew

8) Paralysis of stem at the top or of the branches – Stem necrosis

iii) On head:

9) Head remains erect without seed filling even when other plants show

hanging heads and seed filling – downy mildew

10) Rotting of head, association of maggots, black powdery mass of fungal

spores in abundance – Head rot

6. Diseases of safflower

Part of the plant affected : A) Whole plant B) Leaf / capitulum

A) Whole plant affected:

1) Young seedlings die with rusty pustules on cotyledons – Safflower rust

2) Young seedlings wilt and die, cross section of stem shows blackened vascular

elements – Fusarial wilt

3) Adult plants show progressive wilting, leaf yellowing, partial wilting of the plant,

necrotic lesions on the stem, twisting ad bending of the stem – Fusarium wilt

4) Adult plants show sudden wilting, disintegrated root system, plant can be pulled

off easily, blackened roots, bark peels off – Dry root rot (Macrophomina

phaseolina)

B) Leaf / stem / capitulum:

1) On leaves, brown necrotic lesions with dark margin and concentric zonations,

shot holes – Alternaria leaf spot

2) On leaves, brown necrotic lesions, no margin – Cercospora leaf spot

3) On leaves green and yellow patches appear as mosaic, curling of leaves, cupping,

blistering of leaves, Mosaic virus (Cucumber mosaic virus)

4) On leaves, small brown rusty pustules – Rust

5) On stem, black necrotic lesions, cracking of stem, cankers – Alternaria leaf spot

6) On capitulum, brown necrotic spots on all the parts, testa turns black – Alternaria

leaf spot

7. Diseases of mustard

Part of the plant affected : A) Leaf B) Stem C) Inflorescence

A) Leaf symptoms:

1) White powdery ectoparasitic mycelium seen – Powdery mildew

2) White powdery dot like pustules are seen – White rust

3) Black necrotic lesions with concentric zonations – Alternaria leaf spot

4) Angular yellow spots which later turn necrotic, velvetty fungal growth on the

under side of the leaf (during cooler early hours of the day)

B) Stem symptoms:

1) Twisted stem associated with transparent white velvetty fungal growth – downy

mildew

2) Twisted stem associated with white powdery pustules – white rust.

C) Inflorescence:

1) Malformed twisted stag head (inflorescence) – white rust

ExNo 7: Field diagnosis of important insect pests and disea ses of pulses

GRAM CATERPILLAR Helicoverpa armigera

Symptoms:

Large round on each locule

Caterpillar while feeding it thrusts its head inside the pod leaving the rest of its body

outside.

REDGRAM PLUME MOTH Exelast is atomosa; Spenarches caffer

Symptoms:

���� Small hole on seeds.

���� Dropping of flower buds and flowers in severe cases.

���� Completely eaten and devoured seeds.

REDGRAM POD FLY Malanagromyza obtusa

Symptoms:

���� Discolouration of the infested pods visible in green podded varieties.

���� At the later stage of infestation, the holes about 1mm in diameter covered with a

thin membrane readily seen on the infested pod.

���� Exit holes visible after the adult emergence.

STEM FLY Ophiomyia phaseoli

Symptoms:

When the stem is spli t open the distint tunnel can be observed

along with excreta.

Drooping of the f irst two leaves and wilt ing of the plants

SPOTTED POD BORER Maruca vitrata

Symptoms:

Webbed flowers

Mass excreta is seen at the entrance of larval burrow.

BEAN APHIDS Aphis craccivora Symptoms:

Twisting of leaves, poor pod development, devitalization of plants and sooty

mould

REDGRAM COW BUG Oxyrhachis tarandus Symptoms:

Corky tissues on green stem at all stages of plant

Presence of honeydew on plant which attracts ants like Camponotus

compressus.

REDGRAM POD BUG Cavigral la gibbosa, Riptortus l inearis, Anoplocnemis phasiana

Symptoms:

Shoots fade, pods shrivel and seeds with dark patch loose germination capacity

LEAFHOPPER , Empoasca kerri

Symptoms:

Leaves turn brown, dry and britt le, a condit ion called “hopper

burn”.

Leaflets become cup shaped and yel low at edges.

Heavy attack result in the leaf lets turning red-brown with

subsequent defoliation and stunting.

GREEN PLANT BUG/STINK BUG, Nezara viridula

Symptoms: Fading of shoots

GREEN POD BORING CATERPILLAR OR LENTIL POD BORER Etiel la zinckenella Symptoms:

Faecal pellets inside damaged pods and small round holes on redgram pods

plugged with excreta

.

BLUE BUTTERFLIES Catochrysops cnejus, Lampides boeticus, Catochrysops strabo

Symptoms:

The tiny caterpillars enter into unopened flower bud and feed inside.

Afterwards they may attack another flower or enter a pod and feed on the developing

seeds.

RED GRAM MITE Aceria cajani

Symptoms:

Yellowing of leaves and suppression of flowering and fruiting.

Patches of bushy, pale green plants without flowers or pods.

Leaves are small, show a light and dark green mosaic pattern

PEA LEAF MINER Phytomyza atricornis

Symptoms:

Irregular blotches on leaves.

PEA STEM FLY Melanagromyza phaseoli

Symptoms:

Refer under soybean stemflies.

PESTS OF SOYBEAN

STEM FLY Ophiomyia phaseoli, Melanagromyza sojae

Symptoms:

Distinct tunnel of stem if split open.

���� Death of plant or branches.

LEAF EATING CATERPILLAR Spodoptera exigua

Symptoms:

The caterpil lar causes damage by feeding on leaves. For other

details refer under millets.

SOYBEAN LEAFMINER Aproaerema modicella Calopti l ia soyella

Symptoms:

Field presents burnt symptom when viewed from a distance.

WHITEFLY, Bemisia tabaci

Symptoms:

Damaged leaves show uniform bronzing.

IV Diseases of Pulses

1. Diseases of redgram / pigeonpea

Part of the plant affected : A) Whole plant B) Part of the plant

A) Whole plant:

1) Death of young seedlings in water logged patches in huge number, cupping of

leaves, water soaked lesions on the leaves – Phytophthora seedling blight

2) Sudden wilting and death of the plant, plant can be pulled off easily, no root

portion, appearance of damage by insects, presence of termites – termite

damage

3) Sudden wilt and death of the plant, plants can be pulled off with little difficulty,

dintegration of roots, blackened roots, bark peels off – Dry root rot

(Macrophomina)

4) Progressive death of the plant, yellowing of leaves from bottom to top, linear

elongated necrotic lesions on the stem, cross section of the stem shows

blackened vascular elements – Fusarial wilt

5) No flowering leaves chlorotic, mosaic appearance – Sterility mosaic disease.

B) Part of the plant:

1) Stem: i) Brown, necrotic, bulging at the stem base (galls), stem

breaks of at

bulged portion, plant doesnot die – Phytophthora blight

ii) Necrotic elongated lesions appear externally, extended

from base of the stem, partial wilting, cross section of the

stem shows darkened vascular bundles – Fusarium wilt

2) Leaves: i) Lower leaves turn yellow, drop off, small circular to angular

necrotic lesions with white centers – Cercospora leaf spot

ii) Leaves with black / dark brown angular lesions surrounded

by yellow halo, lesions ad leaf appear rough in texture –

bacterial leaf spot

2. Diseases of balckgram and greengram

Part of the plant affected : A) Whole plant B) Leaf

A) Whole plant:

1) Plant withers and die, appearance of galls / cankers at the base of the plant,

more in hot and dry weather, bark of root peels off, blackened roots –

Rhizoctonia Root rot

B) Leaf:

1) Appearance of white powdery growth – Powdery mildew

2) Appearance reddish brown powdery pustules on the under surface – Rust

3) Appearance of small round spots with dark margin and grayish center –

Cercospora leaf spot

4) Appearance of dark reddish brown circular spots which later expand with

concentric zonations – Corynespora leaf spot

5) Appearance of angular uniformly dark coloured spots without yellow halo –

Angular black spot

6) Appearance of brown angular spots concentrated around main veins with yellow

halo – Bacterial leaf spot

7) Mosaic banding on leaves, complete yellowing of young leaves, necrotic bands in

later stages – Yellow mosaic virus disease

8) Severe leaf curling and crinkling – Leaf crinkle virus disease

3. Diseases of chickpea / bengalgram

Part of the plant affected : A) Whole plant B) Part of the plant

A) Whole plant:

1) Sudden wilting followed by death of the plant especially at the time of flowering,

plant can be pulled off easily, roots turn black, bark on the roots peels off easily,

and small minute dark bodies (pycnidia) on the infected portions – Dry root rot

(Macrophomina)

2) Progressive yellowing, wilting and death of the plant, cross section of the stem

shows discoloured vascular bundles, plants cannot be pulled off easily – Fusarial

wilt

3) Plant suddenly wilts and dies, collar region rotten associated with white cottony

fungal growth and mustard seed like sclerotial bodies – Sclerotium wilt.

B) Part of the plant

1) Leaves: i) Yellowing of leaves - Fusarial wilt

ii) Necrotic lesions on the leaf specially at the tips associated with

dark margin and grayish center, center containing dot like minute

bodies (acervuli) – Ascochyta blight

iii) Brown coloured dot like powdery pustules in concentric circle,

touch gives rusty appearance - Rust

2) Pods: Pods develop necrotic lesions associated with dot like bodies

(acervuli) arranged in concentric circle – Ascochyta blight

ExNo 8: Field diagnosis of important insect pests and disea ses of fibre and sugar crops

COTTON

1. American boll worm: Helicoverpa armigera

Symptoms :

• Bolls showing regular, circular bore holes • Larvae seen feeding on the boll by thrusting their heads alone inside and

leaving the rest of the body outside

2. Pink bollworm: Pectinophora gossypiella

Symptoms :

• Rosetted flowers • Formation of double seeds • Affected buds and immature bolls drop off. • Discolored lint and burrowed seeds.

3. Spotted bollworms: Earias vittella, Earias insulana

Symptoms :

• Drying and drooping of terminal shoots during vegetative stage • Shedding of squares and young bolls • Flaring up of bracts during square and young boll formation stage • Holes on bolls and rotting of bolls.

4.Tobacco caterpillar: Spodoptera litura

Symptoms :

� Scrapping the epidermal layer, leaving the skeleton of veins of leaf � Irregular feeding on the leaves

5. Leafhopper: Amrasca (biguttula biguttula) devastans

Symptoms :

• Tender leaves become yellow. • The margin of the leaves start curling downwards • Typical “hopper burn” symptom. • The leaves dries up and are shed

• Plants stunted in severe cases

6. Whitefly: Bemisia tabaci

Symptoms :

• Chlorotic spots on the leaves • Severe infestation causes premature defoliation • Leaves shining with honey dew and development of sooty mould • Shedding of buds and bolls • Poor opening of bolls

7. Cotton aphid : Aphis gossypii

Symptoms :

• Curling and crinkling of leaves • Plants get weakened and stunted growth • Development of sooty mould

8. Thrips: Thrips tabaci

Symptoms :

• Shriveling of leaves due to scrapping of epidermis and desapping • Scarified terminal buds • Silvery shine on the undersurface of leaves

9. Mealybugs: Maconellicoccus hirsutus, Phenacoccus solenopsis

Symptoms :

• Branches and petioles are covered by white mealy bugs • Distorted and bushy shoots • Crinkled and/or twisted and bunchy leaves • Stunted plants that dry completely in severe cases. • Reduced plant vigour and early crop senescence

10. Dusky cotton bug: Oxycarenus hyalinipennis

Symptoms :

• Sucks the sap from developing seeds in open bolls and stains the lint black. • Seeds discolored and shrunken.

11. Red cotton bug: Dysdercus cingulatus

Symptoms :

• Red stained lint and rotting bolls. • Inner boll wall with warty growth or water soaked spots

12. Leaf roller: Sylepta derogate

Symptoms :

• Leaves rolled in the form of trumpets fastened by silken threads • Marginal portion of leaves eaten away

13. Red spider mite: Tetranychus spp.

Symptoms :

• Fine webs on lower surface of leaves • Reddening of leaves starting from petiole and extend to the total leaf • Leaves become brittle

14. Cotton Stem Weevil: Pempheres affinis

Symptoms :

• Swellings on the stem just above the ground level. • Lack of vigor and strength

15.Grasshoppers: Cyrtacanthacris ranacea; Chrotogonus oxypterus; Catantops annexus; Aeolopus tamulus

Symptoms :

complete defoliation of plants

Mesta : 1.Spiral borer: Agrilus acutus Symptoms:

• Elogated gall just above the ground • 1-3 galls per plant

2. Flea beetle, Nisotra madurensis

Symptoms:

• Small round holes on the leaf lamina

3. Aphid: Aphis gossypii Symptoms:

• Nymphs and adults on lower surface of leaf • Crinkling and twisting of leaves • Development of sooty molds

4. Mealybug: Maconellicoccus hirsutus Symptoms:

• Distortion of leaves and shortening of internodes :Bushy top symptom

• If growing tips are infested vertical growth is suppressed.

• Fibre snaps at point of infestation during retting

5.Mesta hairy caterpil lar: Euproctis scinti l lans

. The early instar larvae feed gregariously on the fol iage.

6.Mesta stem weevil: Alcidodes affaber Symptoms: Gall like swellings on stem and petioles .

Frass is found through holes made on stems.

Stunted growth of plant.

Flowers and fruiting get retarded

7.Leafhoppers Amrasca biguttula biguttula

(Covered under pests of cotton)

PESTS OF JUTE

JUTE SEMILOOPER : Anomis sabulifera Symptoms:

Caterpillar feeds on leaves, as they grow they attack apical buds and top

shoots.

JUTE STEM WEEVIL: Apion corchori Symptoms:

knots are seen on the stem and branching takes place.

JUTE STEM GIRDLER: Nupserha bicolor postbrunnae Symptoms: Stem withering, drooping and finally dying

BIHAR HAIRY CATERPILLAR (Jute): Spilosoma (Diacrisia) obliqua Symptoms:

Defoliation of tender port ions of plants

PESTS OF SUNHEMP

SUNHEMP HAIRY CATERPILLAR: Utetheisa lotrix Argina cribraria Symptoms:

Defoliation of plant, bored seed capsules.

SUNHEMP STEM BORER: Laspeyresia tricentra Symptoms:

Gall like swellings on shoots and stem

Profuse branching of infested plants.

.

SUNHEMP FLEA BEETLES: Longitarsus belgaumensis

Symptoms:

Holes on leaves.

SUGARCANE : 1. Early shoot borer - Chilo infuscatellus Symptoms:

• Dead hearts • Dead heart emits an offensive odour • Bore holes at the base just above the ground level

2. Top shoot borer, Scripophaga excerptalis Symptoms :

• Parallel rows of shot holes in the emerging leaves • Red tunnels in the midribs of leaves • Bunchy top due to growth of side shoots

3.Stem or internode borer: Chilo sacchariphagus indicus Symptoms :

• Internodes constricted • Sshortened with a number bore holes and frass in the nodal region • Affected tissues reddened

4. Leafhopper: Pyrilla perpusilla Symptoms :

• Leaves become yellow • Covered with black sooty mould • Top leaves get dried up and lateral buds germinate

5. Whitefly, Aleurolobus barodensis

Symptoms :

• Yellowing of leaves turn pinkish latter and gradual drying • Development of sooty mold

6. Scale insect: Melanaspis glomerata

Symptoms :

���� Shrivelled canes become with shortened internodes.

Formation of shiny thick encrustation on the cane, maximum on the bottom and middle of the cane

7. Wooly Aphid: Ceratovacuna lanigera Symptoms :

• Whitish powder coating on the leaves and development of sooty mould • Black sooty mould development on leaves

8. Termites : Microtermes obesi, Odontotermes obesus Symptoms: Earthen sheeting at the base of plant Mud filled galleries in shoots Drying of shoots

9.Mealy bug: Saccharicoccus sacchari Symptoms:

Presence of mealy bugs at the nodes within the leaf sheath,

reduced plant vigour and growth,

movement of ants and mould on infested area.

10.WHITE GRUB: Holotrichia serrata, H. Consanguinea Symptoms:

Drying of attacked clumps in patches

11.MITES Oligonychus indicus, Schizotetranychus andropogoni Symptoms:

The leaves turn red in patches.

Chlorophyll is depleted in oval patches.

II. Diseases of commercial crops

1. Diseases of Cotton

Part of the plant affected: A. Whole plant B. Part of the plant

A. Whole plant:

1) Wilting of the plants during cooler months of the season (square formation

stage), leaf drop leaving terminal small leaves, marginal necrosis, cut open stem

shows tiger stripe appearance – Verticillium wilt

2) Partial or complete wilting of plants, Necrosis on stem extending from bottom to

top, yellowing of leaves from bottom to top, complete leaf drop, cut open stem

shows browning of xylem vessels as a continuous ring – Fusarium wilt

3) Sudden wilting of plants, blackening of stem base, bark peels off from roots,

disintegration of secondary and tertiary roots, appear in hot and dry climate,

symptoms appear in patches in field – Charcoal root rot / dry root rot

B. Part of the plant BB. Leaves BBB. Stem BBBB. Bolls

BB. Symptoms on Leaves:

1) Dark brown cicular to oval spots with grayish center associated with dot like

acervuli – Anthracnose

2) Dark brown circular spots associated with purple margin, concentric

zonations, shot holes – Alternaria leaf spot

3) Light brown, irregular spots with brown necrotic center – Helminthosporium

leaf spot

4) Brown to black circular spots with dot like sporodochia arranged in circles –

Myrothecium leaf spot

5) Small, 1-2 mm cicular spots with white center and dark margin – Cercospora

leaf spot

6) Small light brown powdery rust pustules on the under surface of the leaf, in

general, at the end of the season – Phakopsora rust

7) Small brown to black angular lesions around veins with yellow halo, veinal

necrosis, black arm (blackening and death of of branches) – Bacterial leaf

blight

8) Small angular silvery shining spots with white mouldy growth appear initially

on the under surface and later on the upper surface. White mouldy growth

turns black in later stages – Areolate mildew

BBB. Symptoms on stem:

1) Drying and death of branches, oozing from branches – Bacterial leaf blight

2) Elongated, necrotic lesions spreading from basal part of the stem upwards

externally – Fusarium wilt

BBBB. Symptoms on bolls

1) Sunken spots on the bolls with dark margin and white mouldy center, brittle

fibre mass inside bolls – Anthracnose

2) Raised necrotic spots on bolls, rotting of bolls and sticky fibre mass inside

bolls – Bacterial Leaf blight.

2. Diseases of Sugarcane

Part of the plant affected: A. Leaf B. cane / stem C. Whole plant

A. Symptoms on leaf

1) Spindle shaped spots in mid rib with dot like acervuli – Red rot

2) Brown to dark brown, circular to irregular spots with grayish white center –

ring spot

3) Rusty specks on leaves which later turn black and appear as streaks on leaves -

rust

4) Mid rib turns yellow, leaf lamina remains green – Cephalosporium Wilt

5) White albino type of leaves – Grassy shoot

6) Young foliage show chlorotic or yellowish stripes alternating with normal

green portion, stem splitting – mosaic disease

B. Symptoms of cane / stem

1) Reddening of internal pith alternating with white patches, black dot like

acervuli at nodal region – Red rot

2) Red coloured longitudinal streaks, hollowness in the stem (cavities inside the

stem) – Cephalosporium wilt

3) Minute pink coloured pin head like areas near nodes – Ratoon stunting

C. Symptoms on whole plant

1) Drying of 3-4 leaves at the top – Red rot

2) Appearance of apical black whip like structure with black powdery mass –

Whip smut

3) Stunting and Withering of canes – Cephalosporium wilt

4) Numerous lanky tillers, proliferation of axillary buds, thin, weak small canes –

Grassy shoot

5) Stunted growth, reduced tillering, mild chlorosis, shortened internodes –

Ratoon stunting

ExNo 9: Field diagnosis of important insect pests and disea ses of vegetable crops-I

Brinjal 1. Shoot and fruit borer: Leucinodes orbonalis

Symptoms :

• Drooping and withering of terminal shoots • Holes on shoots and fruits plugged with excreta • Petioles and shoots show tunnelling • Shedding of flower buds

2. Hadda beetle: Henosepilachna vigintioctopunctata, Epilachna dodec ostigma

Symptoms :

• Scrapping of chlorophyll of leaves in patches showing ladder like net work of veins

• Skeletonization and drying of leaves

3. Brinjal stem borer, Euzophera perticella

Symptoms :

• Holes on stem • Top shoots of plants may droop and wither • Stunted growth • Larval tunnel inside stem 4. Ash weevils: Myllocerus subfasciatus , M. discolor

Symptoms :

• Notching of leaf margins • Grubs feed on roots

5. Brown leaf hopper: Cestius phycitis

Symptoms :

• Reduction in size of leaves • Shortened petioles, • Conversion of floral parts into leafy structures and • Plants become bushy • Fruiting is rare.

• Vector of disease little leaf of brinjal

6. Lace wing bug, Urentius hystricellus

Symptoms :

• Yellowing of leaves and drying • Exuviae and excreta are found on lower surface of leaves 7. Leaf hopper, Empoasca devastans

Symptoms :

Leaves show yellowing of margins which later turn brown In severe cases, leaves dry up - Hopper burn Vector of brinjal mosaic and little leaf

8.Brinjal mealy bugs: Centrococcus insoli tus

Symptoms: Discolouration of shoots and leaves .

Stunted growth of plant.

Drying up of branches

9.Aphids: Aphis gossypii, Myzus persicae

Symptoms: Crinkling and curling of leaves.

10.Brinjal leaf weber: Psara bipunctalis

Symptoms: Webbed leaves

11. Red spider mite: Tetranychus telarius

Symptoms: Leaves present a characteristic blotches which become whit ish

then brown.

Later the entire affected leaf become discoloured and dried up.

Tomato: 1. . Fruit borer: Helicoverpa armigera Symptoms :

• Young larvae feed on tender foliage while later stages attack the fruits. • Larva bore circular holes and usually thrust only head inside the fruit to

another and may destroy many fruits. • Circular holes on friuts.

2. Serpentine leaf miner : Liriomyza trifolii

Symptoms :

• Leaves with serpentine mines • Silvery mines on upper surface of leaves • Drying and dropping of leaves

3. Fruit borer, Spodoptera litura

Symptoms :

• Irregular holes on fruits and internal content eaten away • Scraping on ventral surface of leaves • Irregular holes on leaves

4. Whitefly : Bemisia tabaci

Symptoms :

• Chlorotic spots • Upward rolling of leaves and crinkling of leaves • Brittle and leathery leaves .

� Vector of tomato leaf curl disease 5. Thrips : Thrips tabac i

Symptoms :

• Silvery streaks on leaf surface • pre-mature dropping of flowers • Bud necrosis. • Vector of tomato spotted wilt virus (TSWV)

6. Root knot nematode, Meloidogyne spp. Symptoms :

• Poor growth of plants • Chlorosis of leaves • Reduced fruit production • Wilting of the plants • Roots show a number of knots

Bhendi: 1. Shoot and fruit borer: Earias vitella , E. insulana .

Symptoms:

• Terminal shoots wither and droop • Shedding of buds and flowers • Holes on fruits • Deformed fruits

2. Bhendi fruit borer : Helicoverpa armigera Symptoms :

• Feed on the flowers • Circular boreholes on

fruitshttp://agritech.tnau.ac.in/crop_protection/crop_prot_crop_insect-veg_bhendi.html -

top

3.Leafhopper : Amrasca biguttula biguttula Symptoms:

• Curling of leaf edges and leaves turn red or brown • The leaves dry up and shed • Plants show stunted growth

4. Red spider mite : Tetranychus telarius

Symptoms:

• Colonies of red mites are found feeding on ventral surface of leaves • Fine silken webs on ventral surface of leaves • Yellow spots on dorsal surface of leaves

5. Whiteflies: Bemisia tabaci

Symptoms:

• Chlorotic spots on the leaves • Severe infestation results in premature defoliation • Development of sooty mould • Vector for the spread of yellow vein mosaic virus disease

Chillies

1. Chilli thrips: Scirtothrips dorsalis

Symptoms: • The infested leaves may curl upward and appear distorted. • Buds become brittle and drop down. • Early stage, infestation leads to stunted growth and flower

production,fruit set are reduced • Vector for the spread of leaf curl virus disease

2.Chilli mite: Polyphagotarsonimus latus Symptoms :

• Affected leaves curl downward along the margins of the leaf and attain an inverted boat shape

• Leaf petioles elongated • Leaves turn dark green and brittle • Stunted growth

3. Pod borer: Helicoverpa armigera Symptoms : • Feeding on leaves by the larvae initially • Pod show a round hole, often the larva is seen by putting its head inside the

pod • and rest of the body outside • Seeds are eaten by larva

4. Pod borer : Spodoptera litura, S. exigua Symptoms :

• Irregular holes on the leaves and fruits • Feed on chilli seed. • Affected pods turn whitish and dry up .

5. Hairy caterpillar: Utethesia pulchella Symptoms : • Larvae feed on the pericarp leaving the seed intact • Ladder like marks are seen on chilli pod 6. Chilli blossom midge: Asphondylia capsici

Symptoms :

• Severe flower drop, • Reduction in yield, fruit size, seed number, production of malformed fruits

7. Aphids: Aphis gossypii Symptoms :

• Nymphs and adults found on lower surface of leaves • Retardation in growth and fruiting capacity of the plant • Deposition of honey dew • Development of sooty mould

.MORINGA :

1. Bud worm: Noorda moringae Symptoms : • Bored flower buds • Drying and shedding of flower buds

2. Leaf caterpillar: Noorda blitealis Symptoms :

• Webbing of terminal shoots • Leaflets become papery structures • Severe infestation leads to defoliation

3. Hairy caterpillar Eupterote mollifera Symptoms :

• Gregarious larvae on tree trunks • Scraping the bark and feed on foliage • Severe infestation leads to defoliation

4. Bark caterpillar: Indarbela tetraonis Symptoms :

• Zig-zag galleries and silken webbed masses on branches

Onion:

1. Onion thrips: Thrips tabaci Symptoms :

• Tiny silvery or brownish patches or spots on leaves • Outer leaves are brown at the tips. • In severe infestation, leaves dry from top to downwards

2.Cut worm, Spodoptera exigua Symptoms :

• Irregular cutting of leaves

Amaranthus:

1.Amaranthus weevil: Hypolixus truncatulus

Symptoms :

• Swelling of stems • Longitudinal splitting of stem. • Suppresssion of root and leaf production

2.Leaf webber : Hymenia recurvalis Symptoms :

• Webbing and skeletonisation of leaves • Excreta, larvae and pupae in webbed leaves

VI Diseases of vegetables

1. Diseases of chilli

Part of the plant affected: A) Nursery B) Main field

A) Nursery: i) Seedligs:

1) Seedlings topple down and die – damping off

2) leaves curl upwards (thrips) or downwards (mites) or due to leaf

curl virus

B) Main field: 1) Leaf:

i) Small angular leaf spots without yellow halo, dark margin

grayish center, spots distributed irregularly on the leaf,

premature defoliation – Cercospora leaf spot

ii) Small angular uniformly coloured spots with yellow halo

concentrated around main veins, veinal necrosis –

bacterial leaf spot

iii) Powdery growth on the lower surface of the leaf,

yellowing and premature defoliation of leaves – Powdery

mildew

iv) Backward bending of petiole blisters and mottling on

leaves – TMV

v) Downward curling, shoestring effect due to undergrowth

of lamina – Cucumber mosaic virus

vi) Vein banding, small and crinkled leaves – PV Y

vii) Mosaic pattern on the leaves associated with ring spots –

Tomato spotted wilt virus

2) Stem:

i) Necrotic lesions on tender twigs, dark margin and grayish

white center, die back of shoot, dried portions associated

with minute dot like acervuli on the under side of the

bark and on the lesions. – Anthracnose / die back

ii) Die back of shoot associated with grey coloured fungal

growth on which dot like aerial sporangiophores arise –

Choanephora blight

3) Fruits:

i) On ripened fruits, fruit scalding (white area on the fruit),

sunken necrotic lesions associated with minute dot like

acervuli distributed in concentric circles on the infected

portions – Fruit rot / anthracnose

ii) On ripened fruits, necrotic lesions without minute dot

like acervuli and instead black coloured fungus

developing in concentric circles – Alternaria fruit rot

iii) Malformed fruits with blisters – Viral infection.

2. Diseases of brinjal

Part of the plant affected: A) Nursery B) Main field

A) Nursery: i) Seedligs: Seedlings topple down and die – damping off

B) Main field: i) Plant: 1. Plants show wilting symptoms, C ross section of stem

shows vascular discolouration, oozing from the infected

cut stem portions – bacterial wilt.

2. Plants show wilting symptoms. Collar region associated

with mustard seed like sclerotial bodies and cottony white

mycelial threads – Sclerotium rolfsii collar rot

3. Plants show wilting symptoms, colar region shows white

fluffy mycelail growth associated with black hard

elongated sclerotial bodies – Sclerotinia collar rot

ii) Shoot/twig: 1. Development of small leaves on shortened internodes at

the apical portions, flowers malformed in to green leaf like

structures – Brinjal little leaf

2. Wilting and paralysis appearance of individual twigs. Cut

open portions show insect excreta / presence of larva –

shoot borer.

iii) Leaf: 1. Black powdery streaks on the lower surface of leaves –

cercospora leaf spot

2. Necrotic lesions with concentric zonations – Alternaria leaf

spot

3. Circular to irregular grayish brown spots with minute dot

like pycnidia – Phomopsis blight

iv) Fruit 1. Small pale sunken spots that cover entire fruit, dot like

minute pycnidia appear on the fruit – Phomopsis fruit rot.

3. Diseases of bhendi

Part of the plant affected: A) Leaf B) Fruit

A) Leaf: 1. Leaves with black powdery stripes on the lower side –

Cercospora leaf spot

2. White powdery mass on both the surfaces of leaves –

powdery mildew

3. Initially yellowing of veins later entire leaf turns yellow –

yellow vein mosaic

B) Fruit: 1. Fruits are small and turn yellow – Yellow vein mosaic.

3. Diseases of tomato

Part of the plant affected: A) Leaf B) Plant C) fruit

A) Leaf: 1. Circular necrotic lesions on leaves with yellow halo, in

general after flower initiation – Alternaria blight

2. Small black specks on leaves – Stemphylium leaf spot

3. Irregular necrotic lesions with dark margin and grayish

center associated with dot like pycnidia – Septoria leaf

spot

4. Chlorotic leaves which later develop brown rings with

center remain green, lesions later turn necrotic, bronzing

of leaves – Tomato spotted wilt virus.

5. Mosaic pattern on leaves, shoe string affect of leaves with

under developed leaf lamina – Tomato mosaic virus

disease

B) Fruit 1. Black necrotic lesions with concentric zonations –

Alternaria blight

2. Necrotic lesions with white halo – bacterial fruit canker

C) Plant 1. Plant wilts and withers, necrosis of apical portions and

stem portions – Tomato spotted wilt virus

2. Wilting of one side of the leaves – bacterial fruit canker

4. Diseases of onion

Part of the plant affected: A) Leaf B) Bulb

A) Leaf: 1. Drying of leaf tips, appearance of purple coloured spots

with light coloured margin and grayish center, papery

appearance of leaf at infected portions – purple blotch of

onion

B) Bulb: 1. Appearance of black powdery mass on the lower side of

outermost scale – Onion smut

2. Appearance of sunken areas on the bulb associated with

minute dot like acervuli especially on white scale onions –

Onion smudge

ExNo 10: Field diagnosis of important insect pests and disea ses of Vegetable Crops-II

CABBAGE 1. Diamond back moth, Plutella xylostella

Symptoms :

• Scrapping of epidermal leaf tissues producing typical whitish patches on leaves

• Holeson the leaves • Pupae in silken cocoons attached to leaf surface

2. Leaf webber: Crocidolomia binotalis

Symptoms :

• Young larva feeds gregariously on leaves • Later webs together the leaves feed within • Excreta present in the webbings

3. Cabbage borer: Hellula undalis

Symptoms :

• Young caterpillars mine leaves, bore stems and feed externally on the leaves. • Damage on the terminal bud • Spin a silken web. • Plants wilt, and frass is exuded from the affected plant parts

4. Cabbage aphid: Brevicoryne brassicae and Mustard aphid: Lipaphis erysimi

Symptoms :

• Yellowing, crinkling and cupping of leaves • Nymphs and adults present on the lower surface of leaf • Stunted growth of plant • Presence of white cast skin at the base of the plant

5. Tobacco caterpillar : Spodoptera litura Symptoms :

• Holes on leaves and heads of cabbage •

6.Painted bug: Bagrada cruciferarum

Symptoms:

Wilt ing and loss of vigour of the plant.

7.Cabbage butterf ly: Pieris brassicae, Pieris rapae

Symptoms: Skeletonisation of leaves

Bored holes in the heads of cabbage and caulif lower.

Cucurbits: 1. Fruit flies - Bactrocera cucurbitae Symptoms :

• Ovopositional marks on the fruits • Oozing of resinous fluid from fruits • Distorted and malformed fruits • Premature dropping of fruits

2. Pumpkin beetle: Aulacophora foveicollis

Symptoms :

• Grubs feeds on the roots, stem and fruits touching the soil • Holes on leaves.

3. Stem gall fly: Neolasioptera cephalandre

Symptoms :

• Swellings or galls between the internodes of stem

4. Snake gourd semilooper: Plusia peponis

Symptoms :

• Large holes on leaves

5. Pumpkin caterpillar: Diaphania indica

Symptoms :

• Webbing of leaves and feeds within. • It also feeds on flowers and bores into developing fruits

6. Leaf miner- Liriomyza trifolii Symptoms :

• Leaves with serpentine mines on upper surface • Drying and dropping of leaves due to severe infestation.

7.Aphids: Aphis gossypii, Aphis malvae

Curling of leaves

• Stunted growth of plant .

• Flowers and pods are also affected.

• Excretion of honey dew

Diseases of crucifers

Part of the plant affected: A) Leaf B) Roots

A) Leaf: 1. Black necrotic V shaped lesions on the margins of the

leaves – Black rot

2. Yellow angular lesions on the upper surface and downy

growth on the under surface – Downy mildew

3. White rusty pustules on the under surface of leaves –

White rust

4. Circular necrotic lesions on leaves with concentric

zonations – Alternaria leaf blight

B) Roots: 1. Plant withers, wilting, uprooted plants show swollen roots

- Club root of cabbage

Diseases of cucurbits

Part of the plant affected: A) Leaf

A) Leaf: 1. Angular yellow coloured lesions on the upper surface of

leaf, correspondingly on the under surface velvety growth

of the fungus seen during early hours of the day, necrosis

in later stages – downy mildew

2. White powdery growth on both the surface of the plant –

Powdery mildew

3. Small circular necrotic spots with dark margin and grayish /

whitish center, spots distributed all over the leaf –

Cercospora leaf spot

4. Mosaic appearance on the leaf with formation of blisters –

cucumber mosaic virus disease

Ex No 11: Field diagnosis of important insect pests and disea ses of Fruit crops

Citrus 1. Citrus leaf miner, Phyllocnistis citrella

Symptoms :

• Serpentine mines on upper side of tender leaves • Silvery appearance of leaves • Distorted and crinkled leaves • Severe attack causes defoliation • Encourage the incidence of citrus canker

2. Citrus rust mite , Phyllocopteruta olevora

Symptoms :

• Fruit colour changes to dark brown • Reduction in fruit size, and dropping of fruits • The rind become hard and brittle.

3. Fruit sucking moths, Eudocima materna, Eudocima fullonica, Eudocima ancilla

Symptoms :

• Adult pierce the fruit and suck the juice • Rottening at the feeding site • Secondary infestation by fungus on affected fruits • Fruit dropping

4. Citrus butterfly , Papilio demolious, P. Polytes Symptom :

• Larvae feed on light green tender leaves • Feeding voraciously and leaving only the mid-ribs

5. Citrus Black fly, Aleurocanthus woglumi Symptoms :

• Leaves are pale coloured and curled • Premature fall of affected leaves • Honey dew excretion and sooty mould on leaves • Severe cases, stunted growth of plant, flowers drop

6. Citrus psyllid, Diaphorina citri Symptoms :

• Nymphs and aduts on the terminal shoots, buds and tender leaves • Honey dew excretion and sooty mould on leaves • Affected plant parts dry • Vector of "Greening" virus

Mango: 1. Mango hoppers : Amritodus atkinsoni,Idioscopus clypealis, I. nagpur ensis

Symptoms :

• Infested panicle shrivels, turns to brown and ultimately dries. • Infested tender fruits also may drop off. • The hoppers also exude 'honeydew' which produce black sooty mould • Heavy egg laying on inflorescence stalks leads to drying and withering.

2. Stone weevil: Sternochetus mangiferae Symptoms :

• Damaged to cotyledons. • Pupae inside the stone. • Discolouration of the pulp adjacent to the affected portions.

3. Mango fruit fly : Bactrocera dorsalis, B. zonatus and B. correctus

Symptoms :

• Punctures on the outer wall of the mature fruits • Maggots feed on the pulp and induce rotting of fruits • Dropping of fruits

4. Fruit borer: Deonalis albizonalis

Symptoms :

• Bored holes on the apex or narrow tip of the fruit • Kernel damage in tender fruits

• Rotting of fruits • Premature dropping of fruits

5. Mealybug : Drosicha mangiferae

Symptoms :

• White mass of mealybugs on fruit stalks and on fruits • Wilting, drying and ultimately fruit setting is affected • Development of sooty mould

6. Shoot gall psylla : Apsylla cistellata

Symptoms :

• Cone shaped green galls on mango shoots • Drying of affected shoots • Less or no fruit set in affected shoots in the next season

7. Mango leaf webber : Orthaga euadrusalis and Orthaga exvinacea

Symptoms :

• Loose webs with neighboring leaves and shoots and feed inside as result the leaves dry up.

• No panicle initiation in the affected shoots in the next season

8. Gall midges: Procontarinia matteiana

Symptoms :

• Small raised wart like galls on tender leaves • Affected leaves get badly deformed and drop prematurely

9. Shoot borer : Chlumetia transversa Symptoms :

• Downward tunneling in growing points of young shoots • Excreta at the entrance hole • Shoots droop , dry and wither

10. Leaf cutting weevil: Deporaus marginatus

Symptoms :

• Cutting of young leaves near the base

11. Stem borer : Batocera rufomaculata

Symptoms :

• Drying of terminal shoot in early stage • Frass comes out from several points and some times sap oozes out of the

holes • Wilting of branches or entire tree

12. Red tree ant: Oecophylla smaragdina Symptoms :

• Webbing and stitching of a few leaves usually at the top of the branches and build their nests.

GRAPES:

1.Flea beetle: Scelodonta strigicollis

Symptoms : • Damaged buds fail to sprout. • Beetles feed on tender shoots and leaves • Rectangular holes on leaves • Tender shoots may wither and drop down.

2. Thrips: Rhipiphorothrips cruentatus

Symptoms :

• A number of minute spots thereby producing a speckled silvery effect • Leaves may dry up and drop off the vine. • Affected berries develop a corky layer and become brown on maturity. •

3. Mealybugs : Maconellicoccus hirsutus

Symptoms :

• Leaves show characteristic curling • Fruits entirely covered with the mealybugs. • Fruit drop or the fruits remain on the shoots in a dried and shriveled condition • Black sooty mould on affected parts

4. Stem girdler : Sthenias grisator

Symptoms :

• GiIrdle around the main stem just above the ground level • Wilting of branches or the entire vine.

5. Tobacco Caterpillar : Spodoptera litura

Symptoms :

• Feed on the leaves and inflorescence. • Cut down the rachis of the grape bunches.

6. Stem Borer : Celosterna scabrator

Symptoms : • Wood dust and faecal matter at the base of the vine • leaves turn yellow in patches • scraping on outer bark

PESTS OF CASHEW

CASHEW TREE BORER: Plocaederus ferrugineus

Symptoms: ���� Yellowing and shedding of leaves and drying of twigs.

���� Chewed up f ibre, excreta and gummy secret ions seen protruding

from the bore holes.

CASHEW SHOOT AND BLOSSOM WEBBER: Lamida moncusalis

Symptoms: ���� Webbed leaves, inf lorescence, apples and nuts

TEA MOSQUITO BUG: Helopelt is antonii

Symptoms:

Brownish black necrotic patches on fol iage and

elongate streaks and patches on shoots

���� Resins exuding from the feeding punctures.

���� Blossom blight and die back symptoms

.

CASHEW THRIPS Rhipiphorothrips cruentatus-Leaf thrips,

Rhynchothrips raoensis: Flower thrips

.Leaf thrips: . Affected leaves turn pale green, later to pale

brown with dark brown spots.

Ult imately the affected leaves shrivel and drop off.

Flower thrips : Flower and fruit drop

scab on apple and green nut.

CASHEW LEAF MINER: Acrocercops syngramma

Symptoms: Whitish patches on the leaf surface of tender leaves.

In older leaves big holes

PESTS OF POMEGRANATE

POMEGRANATE BUTTERFLY / ANAR BUTTERFLY: Deudorix isocrates

Symptoms: Round hole is seen on fruit through which juices come out.

Feeding injury also cause rotting of the fruits.

Offensive smell and excreta of caterpillar at the entry hole.

The affected fruits ultimately falling down.

THRIPS

Anaphothrips oligochaetus (Flower and fruit thrips)

Rhipiphorothrips cruentatus Leaf thrips

Scirtothrips dorsalis

Symptoms: Flowers are shed and fruits show scab like rough surface.

R. cruentatus and S. dorsalis - curling of leaves.

FRUIT SUCKING MOTHS: Eudocima fullonica, E. Materna

Symptoms: Fruits show tiny holes from which juices oozes out when pressed.

Rotting of fruits .

PESTS OF GUAVA

TEA MOSQUITO BUG: Helopeltis antonii

Symptoms: ���� Scab on fruit surface

���� Black linear scars on twigs

���� Reddish streaks on leaves

GUAVA MEALY BUG: Ferrisia virgata

Symptoms: Yellowing, withering and drying of plants or shedding of fruits etc.

���� Formation of sooty mould due to honey dew excretion.

FRUIT FLY: Bactrocera dorsalis, B. diversus, B. zonatus, B. cucurbitae

Symptoms: Premature fruit drop,

fruits with exit holes and soft patches.

SPIRALLING WHITE FLY: Aleurodicus dispersus

Symptoms:

Leaves crinkle and turn to red colour.

The honeydew excretion leads to formation of sooty mould.

PESTS OF SAPOTA

SAPOTA LEAF WEBBER: Nephopteryx eugraphella

Symptoms: ���� The infested trees show numerous webbed shoots, dry leaf clusters and dark

brown patches on the leaves.

PESTS OF BER

BER FRUIT FLY: Carpomyia vesuviana

� The attacked fruits rotting and turning dark brown and smelling offensively.

BER FRUIT BORER : Meridarchis scyrodes

The larva bores into the fruit feeding on the pulp and accumulating faecal

frass within.

BER FRUIT WEEVIL: Aubeus himalayanus

Fruit loses its shape. Fruits become round and fruit stalk bulges.

PESTS OF BANANA

BANANA RHIZOME WEEVIL: Cosmopolites sordidus

Symptoms:

���� Blackened mass of rotten tissue in the rhizome.

���� The plants may show premature withering, the leaves become scarce, and the

fruits become under sized.

���� Very few suckers emerge from the affected plant.

BANANA SKIPPER: Erionata thrax

Symptoms: Rolling of leaves from edges .

Plant vigour is reduced.

BANANA APHID: Pentalonia nigronervosa

Symptoms: Leaf dwarfing, leaf curling is seen.

Fruit bunches become small and the fruits are distorted.

BANANA PSEUDO STEM WEEVIL: Odoiporus longicollis

Symptoms: Tunnels in the pseudostem .

The tunnelled part decomposes and pseudostem becomes weak and easily

breaks in wind.

PESTS OF APPLE

WOOLLY APPLE APHID: Eriosoma lanigerum

Symptoms: ���� The twigs shrivel and die. Young orchard and the nursery suffer the most.

���� Gall like swellings are seen at the feeding site on roots and tree trunks during

winter.

���� The vigour of the trees is reduced.

CODLING MOTH: Cydia pomonella

Symptoms: Bored holes on fruits filled with excreta.

Infested fruits mature earlier and can be identified by their brighter colour and

entry holes.

PESTS OF CUSTARD APPLE

MEALYBUG: Ferrisia virgata (Same as pest of Guava)

V Diseases of fruit crops

1. Diseases of citrus

Part of the plant affected : A) Stem B) Leaf C) Fruit

A) Stem: 1. Oozing of brown gum from the base of the stem – Phytophthora

gummosis

2. Oozing of black gum from the branches, black minute dot like bodies

(pycnidia) formed on the under side of the bark at the affected portion –

Diplodia gummosis

3. Drying of whole plant preceded by yellowing of foliage, bark peels off

from the affected roots, presence of minute sclerotial bodies. – dry root

rot

4. Stem pitting – Tristeza

5. Appearance of bulged portions on the stem, such portions are initially

soft and felt like. Die back of the portion above the infected part – Citrus

felt

B) Leaf: 1. Brown corky raised areas on the leaf, in general associated with leaf

minor symptoms – Citrus canker

2. Black greasy spots on the leaf without any corky formation – greasy leaf

spot

3. White powdery growth on the leaf surface and also on water shoots -

Powdery mildew

4. Black powdery mouldy growth spreading on the entire leaf with sticky

appearance – sooty mould

5. Green islands on leaf which later turn yellow – Citrus greening

C) Fruit 1. Appearance of raised corky areas on fruit rind – Citrus canker

2. Rotting at the base of fruit stalk – stem end rot due to Botryodiplodia

2. Diseases of mango

Part of the plant affected: A) Stem B) Leaf C) Inflorescence / flowers D)

Fruit

A) Stem: 1. Necrotic lesions on young, tender shoots, die back – anthracnose

2. In nurseries, proliferation of side shoots, shortened internodes,

appearance of nest like appearance at the nodes and plant apices –

vegetative malformation.

B) Leaf: 2. Necrotic lesions with grayish center and dark margin, center

associated with pin head sized black bodies (acervuli) on the leaf,

papery appearance of the leaf – anthracnose

3. Black necrotic shiny, angular spots with yellow halo and without

grayish center – bacterial leaf spot

4. Black powdery mouldy growth spreading on the entire leaf with sticky

appearance – sooty mould

5. Green to red coloured rusty raised circular spots, in general without

any necrosis seen on the undersurface of the leaf – red rust

C) Flowers 1. Powdery growth on the flower stalk, severe flower drop – powdery

mildew

2. Necrotic lesions on the flower stalk followed by drying of the stalk –

Anthracnose

3. proliferation of floral stalks, bushy appearance of the inflorescence,

do not bear flowers, flowers converted to green leaf like structures –

Mango malformation

D) Fruits 1. Appearence of black lesions with grayish center on the fruit, lesions

are sunken, appear only after ripening starts, common problem after

purchase from maret up on ripening – anthracnose

2. Appearance of black shiny uniformly coloured, raised spots, skin

breaks off with oozing, stinking smell – bacterial fruit rot

3. Diseases of guava

Part of the plant affected: A) Whole plant B) Leaf C) Fruit

A) Whole plant: 1. Plant shows progressive wilting and death – Fusarial wilt

B) Leaf: 1. Necrotic lesions on the leaf with dark margin and grayish center,

center associated with black dot like acervuli – Pestalotiopsis leaf

spot.

C) Fruit 1. Fruit suddenly dries and falls off prematurely – wilt

2. Young fruit develops necrosis and appear scabby, fruit dries

prematurely, lesions contain dot like acervuli – Guava scab

4. Diseases of sapota

Part of the plant affected: A) Leaf B) Stem

A) Leaf 1. Small circular to oval pinkish to reddish brown conspicuous spots

with whitish center on mature leaves – Phavophleospora leaf spot

2. Initially small reddish borwn specks which later enlarge with dark

margin and grey center with dot like acervuli – Pestalotia leaf spot

5. Diseases of Papaya

Part of the plant affected: A) Plant B) Leaf C) Stem D) Fruit

A) Plant 1. Plant wilts and falls off, rotting at the basal portion of the stem

leaving nly vascular bundles appear as honey comb arrangement –

Pythium foot rot

B) Leaf: 1. White powdery growth on the leaf surface – Powdery mildew

2. Mosaic appearance on the leaves, undeveloped leaf lamina

leaving veins appearing as shoe string – Papaya mosaic virus

disease

3. Downward curling of leaves, reduced leaf size, vein clearing – Leaf

curl virus

C) Fruit 1. Sunken brown spots with dot like acervuli – Anthracnose

2. Brown lesions appear as web on the fruits – powdery mildew

6. Diseases of banana

Part of the plant affected: A) Plant B) Leaf C) Stem D) Fruit

A) Plant 1. Plant wilts with progreesive yellowing of leaves, breaking of

petiole, hanging of leaves except heart leaf, cross section of stem

and rhizomes show vascular discolouration – Panama wilt

2. Young plants die when the ambient temperatures are high, rotting

of rhizomes and suckers, Plants can be pulled easily – Erwinia

rhizome rot.

B) Leaves: 1. Spindle shaped spots along the margins of the leaves with yellow

halo – Sigatoka leaf spot

2. Small dot like raised spots representing pycnidia, several spots

scatter all around the leaf – banana feckle disease

3. Mosaic like discontinuous linear streaking in bands, rotting of

heart leaf – Mosaic virus disease.

4. Purple spindle shaped steaks on bract, clustering of leaves at the

crown giving appearance of travelers palm – Banana bract mosaic

5. On leaves dark green streaks appear giving Morse code

appearance, leaves are small and crowded at the top – banana

bunchy top

7. Diseases of pomegranate

Part of the plant affected: A) Leaf B) Fruit

A) Leaf` 1. Minute angular to circular leaf spots with dark margin and grayish

center without yellow halo, leaves turn yellow and drop off –

Cercospora leaf spot

2. Minute angular uniformly brown coloured (no margin and center

differentiation) leaf spots with yellow halo, spots concentrated

around veins, yellowing of leaves and premature defoliation –

bacterial leaf spot

B) Fruit 1. On fruits, sunken lesions with white to grayish center associated

with acervuli – Anthracnose

2. On fruits, uniformly coloured (dark brown to black) raised shiny

lesions, cracking of fruit rind (L or Y shaped cracks), oozing –

bacterial leaf spot

8. Diseases of grapes

Part of the plant affected: A) Leaf B) shoot / Stem C) Fruit

A) Leaf 1. Yellow angular chlorotic / yellow lesions on the upper surface,

downy / velvety growth correspondingly on the undersurface of

the leaf (in the early hours of the day), necrosis in later part of

infection – Grape downy mildew

2. Powdery growth on the leaf surface – powdery mildew

3. Angular water soaked lesions on leaves (more common in rainy

season) which later turn necrotic brown, lesions are concentrated

around main veins, veinal necosis – Bacterial leaf spot

4. Yellow chlorotic / yellow lesions on the upper surface, rusty light

brown coloured powdery growth correspondingly on the

undersurface of the leaf – rust

B) Shoot / stem 1. Necrotic lesions on the tender shoots, more common in rainy

season, which later expand with dark margin and grayish white

center containing minute dot like acervuli, twig dries above the

point of infection – anthracnose

2. Necrotic lesions on the tender shoots, more common in rainy

season, which are uniformly dark brown or black coloured, twig

dries above the point of infection – bacterial leaf spot

3. Powdery appearance on the tender shoots, withering of the shoot

and sever flower drop – powdery mildew

C) Fruit 1. Small brown to black coloured spots resembling Bird’s eye –

anthracnose

2. Fruit cracking, web like browny patches on the fruit, formation of

water berries – Powdery mildew

3. Downy / velvety growth of the fungus on fruits, formation of

water berries – downy mildew

4. Stalks of the fruits rot and dry, dries stalks and fruits associated

with grey coloured powdery fungus – grey mould / Botrytis mould.

9. Diseases of Apple

Part of the plant affected: A) Leaf B) shoot / Stem C) Fruit

A) Leaf 1. Small velvety brown coloured spots on under surface of just

emerging leaves leaves. Lesions later expand with dark margin

and grayish center – Apple scab

2. Powdery appearance on the leaf - Powdery mildew

3. Water soaked lesions, yellow halo, uniformly coloured necrotic

angular lesions concentrated around main veins, veinal necrosis,

drying of leaf – Fire blight of apple

B) Stem / shoot 1. Necrotic lesions with dark margin and grayish center –

anthracnose

2. Necrosis of young tender twigs from tip downwards, tip of the

shoot bend like shepherd’s hook, turn black and dry – Fire blght

3. Galls and appear at the base of the stem – Crown gall

4. Cankerous lesions on the stem, exudation of gum during rainy

season – Fire blight

C) Fruits 1. Necrotic lesions, cracking of fruit rind – apple scab

2. Cracking of fruit rind, brown lesions on the rind appear as web –

Powdery mildew

3. Necrotic black raised shiny lesions which later rot resulting in

oozing – Fire blight

Ex No 12: Diagnosis of important insect pests, and diseases o f stored grain products and perishables –I. Insect Pests

Stored grains and milled products are subject to attack by a group of insects that have adopted themselves to a diet of dried vegetable material. Many of them are able to live and thrive on vegetable foods that are almost devoid of water.

Significance of Infestation:

• Weight loss • Germination loss • Commercial value loss • Consumer preference loss • Nutritional values loss • Contamination • Heating • Facilitates fungal growth • Storability loss.

Diagnostic symptoms of important storage insect pe sts are,

1.Grain weevils: Rice weevil: Sitophilus oryzae

Maize weevil: S. zeamais

Granary weevil: S. granarius

Symptoms :

• Hollowed out grains • Kernels reduced to powder • Adults cut circular holes. • Heating takes place during heavy infestation

2. Khapra beetle: Trogoderma granarium

Symptoms :

• Infestation is indicated by Presence of cast skins, Frass and hair on bags

• Grub alone damage the grain starting with germ portion, surface scratching and devouring the grain.

• It reduces the grain into frass. • Damage is confined to peripheral layers of bags or 30-45 cm in bulk storage.

3.Lesser grain borer: Rhizopertha dominica

Symptoms :

• Grubs and adults cause damage and are voracious feeders. • Adults reduce the grain kernels to mere frass. • Irregular messy waste flour spots in bagged storage • Heating takes place during heavy infestation • Kernels reduced to mere shells • The damaged kernels remain engulfed in a film of waste flour.

4. Angoumois grain moth or Grain moth: Sitotroga cerealella

Symptoms :

• It attacks both in fields and stores. • Grains are hollowed out. • Infestation remains confined to upper 30 cms depth only. • It feeds inside and remains in a single grain only • Damaged grain give out unpleasant smell

5. Pulse beetle: Callosobruchus chinensis, C. maculatus

Symptoms :

• Grubs eat on grain kernel and make a cavity. • Adults come out making exit holes. • Damaged grain unfit for consumption. • Damaged grain converted to flour by traders give off flavour.

6. Groundnut bruchid: Caryedon serratus Symptoms :

• 'windows' on the pod wall • Circular holes on pods • Each larva feeds within a single kernel.

7. Cigarette beetle: Lasioderma sericorne

Symptoms :

• Grub causes the damage which made circular, pinhead sized bore holes on processed tobacco products like cigarettes, cheroots and chewing tobacco

8.Rice moth: Corcyra cephalonica

Symptoms :

• contaminated food grains with frass, moults and dense webbing.

9.Saw toothed grain beetle: Oryzaephilus surinamensis

Symptoms :

• Adults and larvae cause roughening of grain surface and produce bad odour

• Grains with higher percentage of broken and foreign matter attract heavy infestation, which leads to heating of grain

10.Red flour beetle: Tribolium castaneum

Symptoms :

• Flour beetles are secondary pests of all grains and primary pests of flour and other milled products.

• In grains, embryo or germ portion is preferred. • They construct tunnels as they move through flour and other granular food

products. • Flour greyish and mouldy giving disagreeable odour.

11.Flat grain beetle: :Cryptolestes ferrugineus

Symptoms :

• Larvae and adults are general feeders, • Damage is not readily identifiable as being specifically caused by this insect. • Larvae feed preferentially on grain germ.

12.Potato tuber moth: Phthorimaea operculella

Symptoms :

• Larva mines into the leaf, eventually killing the terminal section of the plant. • In the tuber, the larva tunnels inside, making its way to the heart of the tuber • Rotting and foul smelling of damaged tubers

13. Sweet Potato weevil: Cylas formicarius Symptoms :

• Infested tuber is often riddled with cavities, spongy in appearance, and dark in color.

• Affected tubers bitter in taste and gives terpene odor. • Larvae also mine the vine of the plant, causing it to darken, crack, or

collapse. • Adults make numerous small holes on foliage

Ex No 13: Diagnosis of important insect pests, and diseases o f stored grain products and perishables –II. Diseases

Laboratory tests: Laboratory methods for the detection of seed borne bacteria involve 3 stages i) Extraction from seeds ii) Isolation into culture ii) Identification Bacteria are extracted from the seed flour in a liquid medium, usually sterile pH buffred saline, though buffered sterile water with various other enrichments can be used. The volume and agitation of the liquid medium together with the duration and temperature of soaking are all critical to the optimum recovery of the target pathogen, which may also be affected by the saprophytic microflora of seeds and inhibitor compounds in the seed. Some seed borne bacteria can be identified directly following isolation on general plating agar media, for ex. Peudomonas syringae pv. phaseolicola is cultured on King’s B medium. These non-selective media methods are most effective when high levels of pathogens and low levels of saprophytes are present in extracts. Where high level of saprophytes and low levels of pathogen are present, semi-selective media can be used to reduce the growth of saprophytes. Further identification may be achieved by morphological and biochemical tests, by immunoassays or other molecular biological methods. All of these tests give presumptive diagnoses and most require conformation by a host pathogenicity test. v) Host pathogenicity test : Either the pure culture of a bacterium or the crude seed extract medium is inoculated into the host plant or seeds to test the pathogenicity of the bacteria. Plants are inoculated by a number of different methods, including injection, spraying following leaf abrasion and vaccum infiltration. III. Detection methods for seed borne viruses: i. Growing on tests : They have been used for testing the effects of many seed borne viruses, for ex. Lettuce mosaic virus, Bean common mosaic, etc. ii. Infectivity tests : The local lesion host, Chenopodium armanticolor, or indicator host is inoculated with the extract of infected seed samples and observed for the development of symptoms. iii. Biochemical methods : Viral inclusions can be detected by staining infected seed tissues with 1% phloxin solution. This method is based on fact that viral infections cause biochemical and physiological changes in the host tissues. iv. Serological methods : ELISA is a very sensitive and accurate tool for the diagnosis of seed borne viral diseases. The abbreviation stands for “Enzyme Linked Immuno Sorbent Assay” and most widely used is DAS-ELISA (Double Antibody Sandwich-ELISA). The basic principle is the utilization of a sensitive enzymatic reaction to detect the binding of an antibody to the antigen. In DAS-ELISA, a specific antibody is attached to the inner surface of a suitable container usually a small well in a polystyrene plate known as microtiter plate. When a sample to be tested is poured in this well, viral antigen will bind to the antibody and combined units will remain attached to the well. The next step is to add fresh antibody which has been

conjugated with an enzyme alkaline phosphatase . The conjugated antibody will bind to the virus and activity of the enzyme is measured by adding a suitable substrate like pnitrophenol phosphate . During incubation inorganic phosphate will be split and the solution will turn yellow. The intensity of the yellow colour that can be measured at 405nm in a ELISA reader or spectrophotometer is an indicative of strong enzymatic reaction proving the presence of a high amount of viral antigen in the test sample. v. Electron microscopy : The final confirmation for the presence of plant pathogenic virus can be done by observing through an electron microscope. This can be combined with a serological technique and the procedure is known as Immuno Sorbent Electron Microscopy (ISEM), where the reaction between viral antigens and antibody could be visualized directly to reflect the positive reaction.

ExNo: 14 Plant Protection Equipment and their maint enance

Successful pest management depends not only on the use of proper chemicals at the correct time, but also upon their proper and uniform application by judicious selection of plant protection appliances. Pesticides are generally applied to as dusts, sprays, concentrates, fumigants, aerosols, granules, mist and used for seed dressing. These formulations are used on the crop foliage or to the soils with the help of plant protection appliances or equipments.

Efficient use of crop protection equipments is a very important factor to any pesticide application. Other essential requirement of any plant protection equipment is that it discharges the chemicals at a uniform and controllable rate.

Plant Protection Devices :

Plant protection devices can broadly be classified into following. three categories: (i) sprayers, (ii) dusters, and (iii) fumigators. They are either hand operated or power operated.

Sprayers

The liquid formulations of insecticides are applied to the crops with the help of a sprayer.

The spraying is caused by atomization of the liquid which is brought about by the injection of the liquid into a gas at high velocity or the passage of the gas through the liquid at a high velocity.

Parts of a sprayer:

i. Cylinder: Cylinder is the part of the pump in which pressure is developed.

ii. Plunger: This is also called piston. It forces the liquid spray through the cylinders. The plunger is filled tightly inside the cylinder.

iii. Valves: Usually the ball type and valve seats direct the flow of spray.

iv. Air chamber: It is to equalize the pressure and remove excessive strain.

v. Tank: Spray ingredients are mixed and held in the ~k. vi. Agitator: It is provided to keep the finely divided particles evenly distributed in water.

vi. Pressure gauge: It is lo regulate and maintain the pressure and provides a means of adjustment.

vii. Strainers: Strainers over the intake lo the tank and over the suction pipe leading to the cylinders are of importance to keep the liquid spray free from foreign materials.

viii. Discharge pipe: Discharge pipe should be free from abrupt angles which cut down the pressure between pump and nozzles.

ix. Hose: Its use is to convey the liquid to a desired point. x. Nozzles and spray guns: The actual application of spray is

usually made from an extension rod equipped with nozzle or spray guns.

1. Hand compression sprayer

This sprayer is used to spray the field crops and trees. It is a medium sized machine which is operated by a single man. it gives out the spray due to the air pressure. It may be divided into three main parts : (i) pump (ii) tank and (iii) spraying parts.

First of all the filler cap is opened and the liquid to be sprayed is filled in the

tank. During this operation a strainer should be used. The liquid should be filled up to 3/4 of the total capacity of the tank. A pressure of about 50-60 psi (per square inch) is developed by pumping. The sprayer is then fitted on the back of the operator, with the help of buckles, straps, hooks and waste plate. Then the cut-off cock which is just near the bottom of the tank is opened, thus filling the spray liquid in the hose.

When spraying is to be done, the other cut-off cock which is fitted at the base of extension rod is opened and the spray liquid is thrown out through nozzles in the form of a fine mist by the force of air pressure. The spraying is continued till desired.

2. Paddle pump sprayer

This type of sprayer is more suitable for the field crops and particularly the trees which are 20 ft high.

An iron stand is provided as a base to this prayer. This machine is the assembly of plunger, a stand suction hose, delivery hose, and an extension rod having a spray nozzle at its free end. Since this is a foot operated sprayer, a paddle is attached to the plunger rod to make its up and down movement which ultimately operates the sprayer.

No tank is provided to this sprayer but a separate bucket containing spray

liquid works as a tank. A suction hose which is generally 2 m long and having a strainer at its free end is dipped into the spray liquid which the peddle is pushed down with the foot. The plunger is pushed up into the body of the pump due to which the air is compressed and moves out of the delivery tube. The vacuum thus created results in the filling of the suction tubes with the spray liquid. Continuous paddling is required which sucks the liquid mixture into the body of the sprayer and is released through the nozzle, which can be adjusted for desirable mist. One sprayer with a nozzle is enough to spray one hectare of a medium sized crop in a day.

3. Knapsack sprayer

It has a flat or bean shaped tank (2-5 gallons capacity) which fits comfortably on to the back of the operator. There is an agitator inside the tank. The pump handle extends over the shoulder or under the arm and is worked constantly with one hand while the lance is held with the other for spraying. It is useful for operating over small trees, shrubs, low crops, vegetables or nursery stocks

4. Stirrup sprayer

This consists of a single or double acting pump, which may be clamped or set into a bucket. The single acting pump has one cylinder and exerts pressure only on the down stroke, while the double acting pump has two cylinders, pressure being exerted in once cylinder on the uptake and in the other on the down stroke, thus

maintaining an equal pressure. This is useful for spraying shrubs, hedges and low crops

5. Rocker sprayer

It is provided with a pump or pressure chamber, fitted on a wooden board and operated by a long handle connected with the pump. The pump may be a single or double barrel one. The rocking movement helps in building up pressure in the pressure vessel which forces out the liquid through the nozzle. There is no tank and the suction hose is dipped in a separate spray tank. The principle of working of rocker sprayer is the same as that of foot or paddle sprayer The only difference is that the rocker sprayer is operated by hand, while the paddle is a foot operated one.

It is capable of spraying medium sized fruit trees, plantation crops and field crops

Power operated sprayers The manually operated sprayers are used for small holdings i.e. (4 hectares) and

for large scale spraying, power operated sprayers are required. Broadly speaking, they may be classified into three groups

1. Hydraulic sprayers

Most of the power sprayers are of the hydraulic type in which the spray liquid under pressure created by the pump is forced out through the nozzles in small droplets. The droplets in this case are deposited by the force of the spray and are mostly 150 to 300 microns in size.

The important parts of a hydraulic power sprayer are engine, pump, a tank with agitator, framework with or without wheels, pressure regulator with relief valve, a pressure gauge, suction and delivery hose, lance with nozzle and overflow pipe.

The hydraulic sprayers are operated with 1 to 5 H.P. (horse- power) air cooled engines fitted with single, double or three discharge lines, having discharge capacity of 7 litres to 18 litres per minute at a pressure up to 250 to 500 pounds per square inch. Different types of hydraulic sprayers are available in India.

These sprayers are mostly used for orchards where the spray jets have to reach a good height of 10-15 metres or more.

2. Mist sprayer

These sprayers are essentially low volume sprayers, developed to apply pesticides in a concentrated form. The dilution with water of me spray material is reduced by 20 to 80% or more. There is also a substantial saving in quantity of the chemicals used due to me production of smaller droplets which stick firmly on the surface of the leaves of crops. These sprayers can be used for large areas of small fruit trees, high and dense crops etc.

The mist sprayers are fitted with a low pressure low volume pump which forces the spray material under low pressure through the nozzles into the air stream produced by a fan. The air stream assists in breaking up the liquid into very fine droplets and preventing the droplets from coalescing thus carrying them far to the targeted place where the treatment is required.

The mist sprayers are of two kinds viz. the mist blower and the micronizer. Both the machines work on the same principle, the difference between them is only in the spraying portion of the machine. The former has low volume type spray nozzle and produces small droplets of the material to be sprayed, while the latter has an atomizer linked with the ultra low volume nozzle which produces very tiny droplets and thus covers a greater area within a lower volume of the solution.

The mist blower can be divided into two main components to understand its functioning: (a) the engine and (b) the spray unit Both the units are mounted on a common frame.

3. Fog or smoke generator

These machines disperse the spray material in extremely fine droplets of 1-50 microns in size, which remain air borne for a long time. It is generally used for dense foliage or closed spacing crops where fog takes time to settle and does not drift with the wind. It gives uniform coverage of the object with the chemical. The velocity with which fog leaves the machine is relatively low as compared to discharge from other machines.

The fog generator consists of a tank, with or without an engine, thermal or mechanical arrangements to break up the liquid into the desired droplet size and to create force for carrying the fog from the machine. The machines are mostly skid type and can be transported easily. Small units are also available which work on pulse jet principle and can be carried by one man.

Aerial spraying Aircraft as a means of dispersing agricultural chemicals in fields. It is useful

especially in treating large areas in a short time.

1. Inaccessible crops like sugarcane, paddy, etc. can easily be treated.

2. Delicate crops like cotton, can be sprayed or dusted without disturbing the plant population.

3. Requirement of manpower per hectare is minimum.

4. This method is useful in areas having water scarcity.

5. Large areas can be treated in a short time.

The basic spray equipment with aircraft usually consists of fiber glass tanks of 360 to 540 litre capacity. The tanks are either strapped underneath the fuselage or located inside the cockpit. The pump is powered by a fixed pitch windmill fan driven by the aircraft slip stream. The pumps are either of gear or centrifugal type. The latter ones are more popular because they are simpler and rugged in construction and provide higher flower rates. They are also considerably lighter than the gear type.

There are certain limitations with the aerial spraying of plant protection chemicals. They are briefed here.

1. Field surrounded by hills, trees, buildings etc. are difficult to treat aerially.

2. High temperature and winds cause hindrance in maneuvering the aircraft.

3. Lack of communication between pilot and ground staff makes proper and uniform application difficult.

Dusters

All dusting appliances operate on the principle of emitting a blast of air in which the dust particles are air-borne. Some of the commonly used dusting machines are described below.

1. Hand duster

This is a simple type of duster and contains a dust container, a cylinder with a piston or plunger, rod and a handle. It has a tube with a nozzle at the end of the container.

This works on the simple principle to put forth the dust of air in which the dust particles are suspending. A valve system regulates the direction of the flow of air current As the air passes out, it picks up dust and ejects it through the nozzle.The use of this duster is limited to the small scale research plots, kitchen gardens etc.

2. Hand rotary duster

This duster is large and it is operated by fitting to the left side of the operator. It consists of (i) hopper (drum), (ii) gear box and (iii) blower.

Dust should not be filled more than three fourth of the capacity of the hopper and this must be closed tightly with a lid. The duster is tied to the left side shoulder of the operator with the help of straps provided with the duster, keeping the breast plate on the chest. Lance is attached to the blower properly and reflector is also adjusted according to the need while operating the duster. Operator should move forward slowly in the direction of the wind, rotating the handle continuously to ensure the uniform dust coverage of the crops.

3. Bellow duster

This is the simplest type of duster consisting of a pair of bellows. The dust is placed either in the below or in a separate container attached to one end of the

bellow. Working the bellows creates an air current which forces the dust out through an opening. It is useful for covering small areas. The duster can be made locally by having two pieces of wooden planks or tin, a piece of used car tube and pieces of wooden handles

4. Power dusters

These dusters are operated by means of an engine or a tractor power take off device. A power duster comprises of a hopper containing one or more agitators and a regulator for controlling the discharge of dust. A fan or blower, producing an air blast for drawing the dust from hopper and blowing it out, is also provided along with flexible pipes with nozzles. A dust regulating device adjusts the dust flow at a desired rate ranging from 1 to 10 kg per minute. The machines have arrangements for mixing a blast of air current with the powder. The mixed stream blows out with a velocity of about 320 km/hour.

The fans provided are mostly of centrifugal type with fan case provided with one outlet or a series of four to eight or more outlets. These outlets are connected with flexible pipes to nozzle arranged on a boom in the rear of a tractor for carrying the dust

A power duster with one outlet can dust 12 to 16 hectares per day, depending upon the crop height and dosage

Dusting Vs Spraying

1. Dusting can be used where water is limited or scarce. 2. Dusting is a quicker process as compared to spraying. 3. Sprays are more effective than dusts having the same amount of toxic

chemicals. 4. Sprays are not affected so much by wind as dusts. 5. Excess of spray applied simply runs off, ensuring safety against excessive

deposits. 6. The cost of the dusts is comparatively lower than the sprays. 7. The equipments required for spraying are costlier and heavier than the

dusters. 8. In case of dusting, equal distribution of the chemical on plants is practically

impossible while in the case of spraying it may be obtained to a great degree. 9. Dusting is preferred in morning hours while spraying during evening hours.

Fumigators

Fumigators are generally used to kill insects or other pests by generating the gas through liquid or solid substances. There are different kinds of fumigators but the commonly used one is an ordinary fumigator known as cyno-gas pump.

Cyno-gas pump This fumigator is used for buffing the calcium cyanide powder or the cyno-gas.

It consists Pump cylinder and Plunger rod

Cyno-gas pump is generally used in the fields and god owns to kill rodents,

ants and termites. First of all, the bottle is filled up with the powder up to three-fourth of its capacity and thereafter the lance is inserted after slightly digging the ground or locating the burrows where the rats are present. Following this, the pumping is done and as a result the powder goes inside the burrows. By and large, two ounces of the poison is pumped in each burrow. After the operation is completed the holes should be closed with wet soil or by any other suitable means so that the rats may not come out

Soil injector It is a device in the form of a syringe used for injecting chemicals like

fumigants, pesticides etc., in the soil for destruction of soil inhabiting pests. Two main types are designed namely portable injector, and boom injector. The portable injector is used more commonly than boom injector. It consists of a pump, a container to hold the liquid or gas and a strong hollow injecting nozzle, which can be extended down upto 35 to 40 cm. The pump is then operated by hand to force the chemical into soil.

Other Plant Protection Equipments

1. Seed dressing equipment

Seed dressing appliances or seed mixers are either manually operated or power driven. Commonly used seed dressing equipment ~s hand operated one. It consists of a wooden drum mounted diagonally on two vertical stands which can be rotated upside down by means of a handle. The drum has a small opening in the middle for placing the seed and the dry pesticides. The drum is rotated for 5 to 10 minutes, the seed by this time is fully covered with the pesticide. This type of equipment can treat 10 to 50 kg of seeds at a time, depending upon the size of the drum. Power drive seed dressing equipments are also available but are not so popular among the Indian farmers. It can treat about 5000 kg of seeds within the hour.

A small amount of seeds is also treated with chemicals in earthen or wooden pots. Equipments are also available for wet and slurry treatment of seeds.

2. Aerosol projector

The volatile spray liquid is usually held under high pressure in a bulb-like container. When released, the spray liquid comes out in a fine mist of particles that mixes intimately with the air. These : projectors are valuable in dispersing the pesticides in enclosed spaces i such as stores, glass houses, etc.

3. Flame thrower

It consists of a container for the fuel and a chamber where the fuel is compressed to volatilize and become a gas before being ignited to be projected as burning flame. The direction of the flame can be controlled by using a cover over the burner. It can be operated by one person and is used to destroy weeds and different kinds of insects (such as locusts) and diseases

4. Rat trappers

Various kinds of mechanical devices are used for trapping rats and mice which feed on our field crops or stored grains. The wooden or metal boxes with a door closing mechanism and spring board types are available. Some of these traps are made by arranging pegs, sticks, strings, earthen pots, rubber pieces, etc.

Generally one rat is trapped at a time. In most of these traps baits are used for attracting moles, rats and mice.

There are some other traps which are slightly complicated. These are cart mounted and have power operated blowers in which hard coal or bitumen is burnt The poisonous gas is conducted through a hole or tunnel into the burrows and this ensures quick killing of the rodents.

Tractor -pulled applicator with a special plough share is also

employed. This makes art if ic ial tunnels which are connected to the

burrows made by the rodents. The poisonous baits are scattered in the

artif ic ial tunnels. When rodents move around and feed on these baits,

they are kil led. The problem with this equipment is that the artif ic ial

tunnel sometimes may collapse if the soil is l ight

5. Bird scarer

Various methods are employed for scaring birds damaging the mature crops in the fields. In general, farmers prefer to hang pieces of tin or aluminium around their fields for producing loud noises at regular intervals to drive away the birds. They also hen red bottles around their fields to scare away the birds attacking the crops. Harmless shooting is also practiced in orchards to scare away birds. These practices are also useful to keep away the wild animals from the fields and orchards.

Care and Maintenance of Plant Protection Devices

Reliable, durable, efficient and mechanically sound equipment is essential for obtaining the maximum benefit from crop protection operations. The following precautionary measures are taken for proper maintenance of the machines.

I. Always follow the manufacturer's instructions and directions with regard to lubrication, operation and maintenance of equipments.

2. Clean all parts of machines thoroughly after use and store them in a dry place.

3. Flush the equipment with clean water to wash the inner parts of the containers, tubes and nozzles to keep them free from chemicals.

4. The hose and nozzles of the sprayer should be thoroughly washed with clean water after use and kept dry. Similarly, the dust from the dusters should be removed and they should be properly cleaned with a cloth.

5. The moving parts should be greased and oiled regularly. 6. Keep the machines in a working order by following a regular maintenance programme.

7. The oil should be kept at the required level in the power operated equipments.

8. The rubber hose should not be bent while in the use and should be removed and kept rolled which not in use.

9. Always keep in stock spare parts, washers, nozzles, etc. for replacement when the old parts get worn out.

10. Insert pump valve seat, plunger cups and packing at least once a year to check. on leakage.

11. The spray liquid should be strained and the dust shifted to avoid clogging of the nozzles and the delivery tube.

12. Test pressure regulator and pressure gauge periodically for efficient functioning of the sprayer.

13. Change oil regularly in the crank case to prevent the corrosion of the bearings, gears and shafts.

14. Do not drop the nozzles for a sprayer and the delivery tube of duster on the ground. Keep all these parts on a clean cloth or tarpaulin while servicing the machine.

15. Take all care and precaution while transporting and shifting the equipment from one place to another.

16. Do not handle the machine especially the power driven, unless you know the job well.

17. Test the pressure regulator and pressure gauge before use for efficient functioning of the sprayer. Defective pressure regulator creates uneven pressure and may spoil the gauge.

18. Store all these devices in an isolated room which is well ventilated and dry. Children should not be allowed to handle the instruments.

Precautions During Application of Pesticides.

1. Do not let the spray liquid of the pesticides come in contact with the body of the operator while preparing solution and filling the spray tanks. A funnel with a strainer should be used while filling the liquid.

2. A void mixing the spray solution with hands, instead a wooden stick should be used.

3. Empty pesticides containers should not be used for any other purpose. Destroy them if they cannot bc reused.

4. Do not allow the nozzle to soil. The clogged nozzles should not be blown by mouth for clearing dirt. Dragging of hose on the ground should be avoided. It should be prevented from snagging.

5. The spraying or dusting should not be done against the wind direction.

6. Leaking sprayers or dusters should not be used. .Such equipments arc likely to cause accidental poisoning of the operator. Protective clothing should be used during the application.

7. The operator should not drink, eat, or smoke during the operation. He should change his clothes and have a thorough wash after the application.

8. The application of pesticides should be avoided, as far as possible, on a rainy day, when high temperature and wind prevails.

9. Animals should be kept away from the site of operation and should not be allowed to graze in the field at least two to three weeks after application.

10. The crop should not be treated 2 to 3 weeks before harvesting.

11. As far as possible, the application of pesticides at flowering stage of the crop should be avoided to ensure proper pollination.

12. If there are any bee-hives in the field or orchard to be treated, they should be transferred to some safe places and can be brought back after two or three weeks of the application.

13. A separate sprayer should be used for the application of Weedicides of herbicides as far as possible.

***

ExNo: 15 Laboratory test: Isolation of plant pathog ens from diseased material. Test for identification of Plant Pathogens viz., fungus, bacteria and virus. Final diagnostic report

A) Isolation of plant pathogenic fungus / bacteria

Objective: To isolate plant pathogenic fungus / bacteria from a diseased foliar part of the plant.

Introduction: When a part of the plant is diseased and dead, it attracts several saprophytic microbes. While observing under microscope it is possible that we get some of the saprophytes also contaminating the main pathogen. Hence it is necessary to isolate the pathogen in vitro so that Koch’s postulates can be proved before confirming the observed microbe as the pathogen.

Materials: 1. Autoclave

2. Inoculation chamber

3. Incubator

4. Petriplates

5. Conical flasks

6. Cotton

7. Inoculation needle (for fungi) / Inoculation loop (for bacteria)

8. Rectified spirit

9. Sodium hypochlorite solution

7. Rubber bands

8. Plastic covers

9. Foreceps

10. Diseased specimen – leaves (for fungal isolation) and canker affected fruits (for bacterial isolation)

11. Media:

Potato Dextrose agar (PDA) – Peeled potatoes: 200g,

Dextrose: 20g,

Agar-agar: 20g

Water: 1000ml

Nutrient agar (NA) - Peptone: 5 g

Beef extract: 3 g

Na Cl: 5 g

Agar-agar: 15-20g

Water: 1000ml

pH adjusted to neutral (6.8)at 25 OC

Methodology 1: For fungal isolation.

1. Collect fresh diseased specimen from field preferably in the early hours of the day (due to presence of dew sporulation is maximum).

2. Cut the diseased portion of the leaves in to small 3-5 mm pieces in such a way that half of it contains diseased portion and remaining half healthy portion.

3. Surface sterilize the pieces by placing them in Sodium hypochlorite solution (4%) for 2-3 minutes (more time if the diseased portion is hard) and transfer them in to sterile distilled water placed in glass plates adjacent to the hypochlorite solution three times to remove all the residues of hypochlorite.

4. Place the surface sterilized diseased specimen pieces (1-3) in to sterile PDA plates under aseptic conditions and incubate the plates for the growth of fungi.

5. Observe the growth of fungus and identify the fungus based on its morphological features.

6. Draw neat labeled diagrams of the fungal structure as observed under microscope.

Methodology 2: For bacterial isolation.

1. Collect fresh diseased specimen from field preferably in the early hours of the day (due to presence of dew sporulation is maximum).

2. Cut the diseased portion of the leaves in to small 3-5 mm pieces in such a way that half of it contains diseased portion and remaining half healthy portion.

3. Surface sterilize the pieces by placing them in Sodium hypochlorite solution (4%) for 2-3 minutes (more time if the diseased portion is hard) and transfer them in to sterile distilled water placed in glass plates adjacent to the hypochlorite solution three times to remove all the residues of hypochlorite.

4. Place the surface sterilized diseased specimen pieces (1-3) in to sterile distilled water in test tubes and allow for 5 minutes so the bacterial cells oozes in to the water.

5. Take an inoculation loop, sterilize to red hot, cool and then dip in the bacterial suspension prepared in step 4. Using the loop streak sterile nutrient agar plates under aseptic conditions and incubate the plates for the growth of fungi.

6. Observe the growth of bacteria and identify the bacteria based on its morphological and physiological features.

B.Tests for identification of plant pathogens.

Examination using microscope of higher magnification

� Identify fungi to genus or to species. � View bacterial flow; observe morphology at highest magnification. � View virus inclusion bodies. � Using electron microscope, view viruses, phytoplasmas

Moist Incubation

� Goal – to induce sporulation � Important for obligate fungal pathogens � Avoid excess moist conditions.

Fungal isolation

� Surface sterilize. � Use margin of diseased area. � PDA media, can be selective � Diagnostician can often identify to genus from appearance of culture

Fungal identification – Other methods

� Examination and comparison with drawings in literature � Utilizing keys in literature � Literature sources for host diseases and disorders � Serological, molecular, other tests

Bacterial isolations

� Grind tissue in sterile water. � Streak suspension on bacterial medium. � Can use selective media � Transfer single, isolated colony

Bacterial identification

� Ooze test � Biochemical tests � Carbohydrate utilization (BIOLOG) � Fatty acid methyl ester analysis (FAME) � Molecular methods � Polymerase chain reaction (PCR) � Serological tests, e.g. ELISA

Identification of other pathogens: Non-culturable pathogens

� Viruses, viroids � Phytoplasmas � Fastidious bacteria

Methods

Electron microscopy, Staining for virus-induced inclusion bodies, Molecular tests e.g. PCR, Enzyme activity testing, host range testing, ELISA

Serological tests, e.g. ELISA Serological methods:

ELISA is a very sensitive and accurate tool for the diagnosis of seed borne viral diseases. The abbreviation stands for “Enzyme Linked Immuno Sorbent Assay” and most widely used is DAS-ELISA (Double Antibody Sandwich-ELISA). The basic principle is the utilization of a sensitive enzymatic reaction to detect the binding of an antibody to the antigen.

In DAS-ELISA, a specific antibody is attached to the inner surface of a suitable container usually a small well in a polystyrene plate known as microtiter plate. When a sample to be tested is poured in this well, viral antigen will bind to the antibody and combined units will remain attached to the well. The next step is to add fresh antibody which has been conjugated with an enzyme alkaline phosphatase. The conjugated antibody will bind to the virus and activity of the enzyme is measured by adding a suitable substrate like p-nitrophenol phosphate. During incubation inorganic phosphate will be split and the solution will turn yellow. The intensity of the yellow colour that can be measured at 405nm in a ELISA reader or spectrophotometer is an indicative of strong enzymatic reaction proving the presence of a high amount of viral antigen in the test sample.

ExNo: 16 Plant Quarantine

Insects, mites, nematodes, fungi, bacteria, viruses, MLOs and other organisms are known to attack various crops of economic importance. These pests

and pathogens not only reduce the quantity but also spoil the quality of the produce to a considerable extent. Plant quarantine defined as 'Rules and regulations promulgated by governments to regulate the introduction of plants, planting materials, plant products, soil, living organisms, etc. with a view to prevent inadvertent introduction of exotic pests, weeds and pathogens harmful to the agriculture or the environment of a country/region, and if introduced, to prevent their establishment and further spread'. Plant quarantine is thus designed as a safeguard against harmful pests/pathogens exotic to a country or a region. Plant quarantine measures aim at providing protection to the agriculture of a country or region against the likely ravages of alien pests/pathogens should they get introduced and established. Quarantine not only helps to ward off the threats of exotic pests, but also aim to eliminate and prevent further spread of pests/pathogens (both indigenous and introduced) with restricted distribution within the country (domestic quarantine).

Pest/pathogen detection techniques:For quarantine purposes, techniques should be sensitive enough to detect even trace infections. Detection techniques would vary depending on the type of material, the host species and the type of pests/pathogens involved. Detection techniques may broadly be classified into two groups: Generalized tests and Specialized or specific tests .

Generalized tests:A very widely used method is the inspection of dry seed with the naked eye or under the low power of microscope. This method would reveal a wide range of free moving insects, their eggs and larval stages, mites on or with the seed, weeds, soil, infected/infested plant debris, fungal fructifications etc.

Examination of dry seed under UV light may reveal infections of certain fungi and bacteria through emission of fluorescence of different colours. Examination of seed washings may reveal surface contamination by rusts, smuts, downy mildews and a large number of other fungi.

Most commonly used incubation methods for the detection of fungi are the common moist blotter and agar tests wherein seeds are incubated on these media for a specific length of time (generally about a week) at a suitable temperature under alternating light and dark cycles. These two media reveal a wide range of internally seed-borne fungal and some bacterial pathogens in a wide variety of crops.

Seedling symptom test and the growout test are quite versatile and reveal the symptoms produced by any category of plant pathogens including fungi, bacteria and viruses. However, some viruses may be carried symptomlessly in the plant and, therefore, it should be used in combination with other tests like indexing on indicator test plants and serology.

Specialized tests:

Insects: X-ray radiography is useful for the detection of hidden infestation (with no apparent sign of infestation on the seed surface) of insects, particularly seed infesting chalcids and bruchids.

Seed transparency test (boiling the seeds in lactophenol to make them transparent) may also be used for the detection of hidden infestation and extraction

of the insects for identification. X-ray radiography is also very effective in salvaging infested seed lots.

Nematodes : For the detection of seed-borne nematodes, seeds are soaked in water for about 24 hours. This makes the nematodes active, which then come out of the seed into the water, or the seeds may be teased out with the help of forceps and a needle and examined for detection of nematodes under a stereo microscope. In rooted plants, the accompanying soil and plant debris may similarly be soaked in water and nematodes may be extracted for identification using nematological sieves.

Fungi, bacteria and viruses: Serological tests are very effective for the detection and identification of viruses and bacterial pathogens. Indicator test plants are also very helpful as they may reveal pathogenic races within a species of a fungus, bacterium and specific strains within a virus.

In the case of vegetative propagules, laboratory methods may suffice for the detection of insects and mites, nematodes, majority of fungi and certain bacteria. However, for the detection of systemic fungal pathogens, bacteria, viruses, viroids and MLOs, isolation growing for a season or a year or more in quarantine glass-houses/net-houses is required.

Salvaging of infested/infected material:Once the insect or pathogen or weed is detected in the introduced planting material, quarantine officials must make all efforts to disinfect/decontaminate the material and make it available for further exploitation in the country without undue delay. For quarantine purposes, no residual inoculum of exotic pests/pathogens must remain. Fool-proof eradicative treatments are required to be employed before release of the planting material from quarantine.

Fumigation: Fumigation of the material under atmospheric or under reduced pressure is acceptable as a quarantine treatment against insects and mites. Fumigants like methyl bromide, HCN, phosphine and EDCT (ethylene dichloride + carbon tetrachloride mixture) are commonly used.

Heat treatment: Hot water treatment or hot air treatment are also used in quarantine for eradication of insects, mites, nematodes, fungi, bacteria and viruses. The basic principle involved is that treatment temperature should be sufficiently high to kill the associated pest/pathogen but not the host. Some recommended hot water treatments are

1. Nematodes: Flower bulbs, 44° C for 240 min; chrysanthemum, 48° C for 25 min; potato tubers, 45° C for 5 min; 2. Insects and mites: Narcissus bulbs, 44° C for 180 min; strawberry runn ers, 46° C for 10 min 3. Bacteria: Crucifer seeds (black-rot pathogen) 50° C for 30 min 4. Fungi: Celery seed, 50° C for 25 min; wheat seed, 52-54° C for 10 min 5. Viruses: Grape vine, 45° C for 120-180 min; sugarcane setts, 50° C for 120 min.; potato tubers, 50° C for 17 min;

Chemical treatments: Chemicals may be applied as dust, slurry, spray or as dip. It should be ensured that dosage of chemical should be enough to eradicate the inoculum but should not kill the host. The choice of the chemical and dosage to be used should be made depending upon the pest/pathogen involved. Seeds treated at origin are not only difficult to examine but are hazardous to inspect also. Heavily treated seed, which makes inspection difficult, should be denied entry .

Tissue culture: Tissue culture method reduces the pest/pathogen introduction risk in two ways: (i) the size of the consignment is very much reduced since the introductions are represented by meristem tips, excised buds or embryos, and (ii) the aseptic plantlet system has built-in pest/pathogen detection capability. All insects, mites, nematodes and most fungi can be eliminated. Symptoms on young seedlings, and growth of the organisms on the agar medium, if any, may be visible through the transparent culture tubes, and these could be discarded. However, certain systemically infecting pathogens like rusts, downy mildews, bacteria, viruses, viroids and MLOs, may still get transported.

Examination of pest/pathogen risk in plant introduction

Analysis of pest risk in plant introduction is essential to decide as to whether a particular planting material could be permitted entry or not. Such risk analysis provides sound biological basis to decide quarantine policies. The attitude towards 'entry status' of a material may be liberal or conservative depending on the risks involved in its introduction. If risks are low, quarantine would be liberal in permitting the entry.

Quarantine regulations

Plant quarantine regulations are promulgated by the national and the state governments to prevent the introduction and spread of harmful pests and pathogens. Plant quarantine will be justified only when the pest has no natural means of spread and when they are based on biological considerations only, i.e., pest/pathogen introduction risks and the available safeguards. In general, risks are more with the introduction of vegetative propagules than with true seed. In case of true seed, risks are more with deep-seated infections than with the surface borne contamination of pests/pathogens.

Based on these factors, plant quarantine regulates the introductions as follows:

1. Complete embargo/prohibition: When the pest risk is very high, the safeguards available in the country are not adequate and, therefore, import is prohibited.

2. Post-entry quarantine: The risk is very high but adequate safeguards in the form of post-entry isolation growing facilities are available.

3. Restricted: Pest risk is not high and import permit is required stipulating conditions for entry, inspection and treatment.

4. Unrestricted: Import permit is not required, and material may enter without restriction.

While formulating quarantine regulations, local conditions like crop spectrum and environmental conditions are also to be considered. Since quarantine regulations are designed to break the life cycle of the pest/pathogen involved, the presence of alternate or collateral hosts in the country of import and their introduction should also be taken into account.

Plant quarantine system in India

Plant quarantine activities in India are carried out under the Destructive Insects and Pests Act (DIP Act) of 1914, and the rules and regulations framed from time to time there under by the Govt. of India . The Directorate of Plant Protection, Quarantine & Storage, headed by the Plant Protection Adviser to the Govt. of India, is primarily responsible for enforcing the quarantine rules and regulations framed under the DIP Act in the country. Seed was not covered under the DIP Act until 1984, when the Govt. of India brought forward a comprehensive 'Plants, Fruits and Seeds (Regulation of Import into India) Order, 1984' which came into force in June 1985.

With a view to provide the farmers the best planting materials available in the world for maximising productivity per unit area and to encourage the private seed industry in India not only to meet the internal requirements but also to develop export potential for high quality planting materials, the Government of India anounced a 'New Policy on Seed Development' in September 1988. The new policy covers the import of seeds/planting materials of wheat, paddy, coarse cereals, oilseeds, pulses, vegetables, flowers, ornamentals and fruit crops; procedures for their import and the related plant quarantine procedures/requirements.

For this purpose, plant quarantine and fumigation stations have been established at various international airports, seaports and land custom stations where the incoming consignments are inspected, fumigated or otherwise disinfested/disinfected before release to indentors. Quarantine and fumigation stations under the Directorate of Plant Protection, Quarantine & Storage handle bulk imports for commerce and for planting.

The main features of the existing plant quarantine regulations in India are as follows:

1. No consignment of seeds/planting materials shall be imported into India without a valid 'Import Permit', which is to be issued by a competent authority, to be notified by the Central Government from time to time in the Official Gazette.

2. No consignment of seeds/planting materials shall be imported into India unless accompained by a 'Phytosanitary Certificate', issued by the official Plant Quarantine Service of the source country.

3. All consignments of plants and seeds for sowing/propagation/planting purposes shall be imported into India through land customs station, seaport, airport at Amritsar, Bombay, Calcutta, Delhi and Madras, and such other entry points as may be specifically notified by the Central Government from time to time, where these shall be inspected and, if necessary, fumigated, disinfested/disinfected by authorised plant quarantine officials, before quarantine clearance.

4. Seeds/planting materials requiring isolation growing under detention, shall be grown in post-entry quarantine facility approved and certified by the Designated Inspection Authority (DIA) to conform to the conditions laid down by the Plant Protection Adviser to the Govt. of India.

5. Hay, straw or any other materials of plant origin shall not be used as packing material.

6. Import of soil, earth, sand, compost, and plant debris accompanying seeds/planting materials shall not be permitted. However, soil can be imported for research purposes under a special permit issued by the Plant Protection Adviser to the Govt. of India.

Most of the plant material enters the country as air cargo or air mail parcels. Passengers going abroad also bring seed/planting material with them. The New Seed Policy now permits private enterprises to introduce more material in certain cases under 'Open General Licence'. Bulk consignments for consumption or sowing are brought by ships, and small research consignments through air freight or post. Therefore, the customs department, postal department, the International Airport Authority and Port Authority of India are also involved.

The customs department, postal department, the International Airport Authority and Port Authority of India should ensure that the consignments/post-parcels containing seeds/planting materials are cleared promptly and are sent compulsorily to the plant quarantine services. The consignments should never be released directly to the users. All international airports/sea ports/international post offices should have plant quarantine counters alongwith the customs counters:

Role of NBPGR:National Bureau of Plant Genetic Resources (NBPGR), New Delhi is the national nodal agency for exchange of germplasm material of agri-horticultural and agri-silvicultural crops for research purposes in the country. The Director of NBPGR is empowered to issue 'Permits' for import of seeds/planting materials/germplasm collections for research purpose.

General considerations

Plant quarantine can be effective only if it is based on sound scientific considerations. Pest/ pathogen introduction risk only should be the guiding principle of our national quarantine policy. Following suggestions to users of germplasm are made in this regard:

1. Bulk imports of planting materials should be discouraged as far as possible because the pest/pathogen introduction risk increases in proportion to the quantity of material. It is so because thorough examination and treatment of bulk consignments is difficult and the area under cultivation becomes too large for effective monitoring of the crops. If it becomes absolutely essential to import propagating material in bulk, it should be imported from seed companies/agencies reputed to produce seed/planting material under strict phytosanitary conditions.

2. Bulk imports for consumption should be de-vitalized making them unfit for planting and these should be processed immediately on arrival under supervision of quarantine officials.

3. All imports, whether for consumption or planting for commercial or for research purposes, should be done under 'Import Permit' only, and all conditions mentioned in the permit should be strictly followed.

4. All the plant material being brought by passengers coming to India must be handed over to the plant quarantine officials for inspection at the international airports/seaports, where separate 'Plant Quarantine Counters' should be established urgently.

5. At the international post-offices, all the mail should be passed through some kind of detection or scanning system as is done at the time of security check, and intercepted plant materials should be passed on to the plant quarantine officials for inspection.

6. In case of germplasm, repeat introductions should be avoided as the pest risk increases with repeat introduction of germplasm material into the country. All requests for germplasm should be routed through this Bureau alone.

7. Domestic quarantine is as important as the international quarantine and, therefore, planting material should be moved from one state to another or from one place within a state to another under strict phytosanitary conditions.

8. Effective linkages/cooperation should be established among various organisations/agencies involved in the import of plant material for effective plant quarantine implementation and smooth flow of material.

9. Periodic workshops/meetings at national level involving concerned departments may be held to discuss common problems and impediments so as to help the national crop improvement programme.