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Chapter I

INTRODUCTION

Maize,Zea mays(L.) (Poaceae), ranking third in area after wheat and rice is one of the important

cereal crops in the world. In India, maize was cultivated over an area of 8.55 million hectares, with a

production and productivity of 21.73 million tones and 25.40 q ha-1

, respectively in 201011 (Anonymous

2011). The maize production in India has increased more than 12 times from a mere 1.73 million tonnes

in 195051 to 21.73 million tonnes at present. However, during 201011 it was grown in 133 thousand

hectares with a production of 491 thousand tonnes in the Punjab (Anonymous 2012). The demand for

maize will touch 42 million tonnes by 2025, of which 2021 per cent will be used for human

consumption, more than 60 per cent as poultry and livestock feed and remaining 12 13 per cent for

industrial raw material (Anonymous 2011).

The generation of new agricultural technology in India during last 50 years has not only helped to

increase production of maize but also has given rise to new cropping patterns. This has led to round the

year cropping of maize in one or the other region of Indian union (Panwar 1998) and offers a bright

prospect in crop diversification in the Punjab, where its cultivation is recommended in kharif, rabi and

recently in spring season too (Anonymous 2006). The cultivation of spring maize is becoming popular

because of its higher yield potential. The productivity level of maize in the Punjab after the

recommendation of cultivation of spring maize in the state, has gone up by 34.9 per cent in 2011 with

productivity of 36.93 q ha-1 than that of 27.38 q ha-1 in 2005 (Anonymous 2006, 2012). The average

productivity of maize in India (2 t/ha) wasquite low in comparison to the major maize producers in Asia

(Sharma et al 2006). The attack of insect pests at various crop growth stages poses serious limitations in

full manifestation of yield potential of maize during different seasons. Although 139 insect pests are

reported to cause varying degree of damage to maize crop from sowing to harvest, but only about a dozen

are quite serious and require control measures (Siddiqui and Marwaha 1994). However, according to

Mathur (1987), the total number of insect and mite pests exceeds 250 in India. The insect pest complex

changes in time and space and their incidence in maize has increased due to its large scale cultivation as

sole crop and widespread use of pesticides for pest control. The insects hitherto unknown to attack the

maize have become problems (Kumar et al 2005, Kumar and Kanta, 2011). The continuous planting of

maize has led to the invasion of polyphagous shoot flies species as the key pests on spring sown maize in

the northern India (Sarup et al1984). The incidence and extent of losses by insect pests complex to the

newly recommended cultivation of maize during spring season in the Punjab is not available.

Among the different species of shoot fly prevalent in north India,Atherigona naqviiSteyskal is a serious

pest of spring sown maize in the Punjab (Sandhu and Kaushal 1976, Singh and Kanta, 2004). The


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maggots of shoot fly attack the emerging seedlings and feed on the whorl leaves causing deadhearts in

small and slowly growing plants and resulting in curled and distorted leaves in bigger plants (Panwar

2005, Kanta et al 2006). The severity of the pest can be judged from the fact that up to 85.8 per cent

deadhearts incidence was reported from spring-sown maize in the Punjab (Sajjan and Sekhon 1985) and

even the 15 days delay in adoption of control practices may result in yield losses to the tune of 32.4 per

cent (Gagandeep and Kanta 2007a). As the adult flies oviposit on the emerging seedlings and in cracks

and crevices around the seedlings, the soil application of carbofuran 3 G @ 12.5 kg and phorate 10 G @

10.0 kg per hectare at sowing time (Sajjan and Sekhon 1985, Kanta et al 2006) and seed treatment with

imidacloprid 70 WS @ 5 g per kg seed and imidacloprid 600 FS @ 6 ml per kg seed one day before

sowing was found effective and recommended for control of shoot fly in Punjab (Jindal and Hari 2008,

2011). However, the use of chemical pesticides is hazardous to the beneficial organisms and the

environment; and the management strategy for any pest must involve more than one control tactics.

Moreover, shoot fly, in general, is not easily accessible to insecticides sprayed on maize as the larvae feed

inside the leaf whorls.

The exploitation of host plant resistant also has a good potential for the management of shoot fly.

The use of resistant cultivars is a realistic alternative to chemical control, if they are able to compete

economically with the commonly used hybrids and varieties (Raina, 1985). In India, up till now, about

2000 maize germplasm lines have been screened against Atherigona species and number of resistant

sources has been identified by various workers from different locations, but the levels of resistance are

low to moderate (Siddiqui et al 1988, Panwar 2005, Jindal et al 2007, Kumar and Kanta 2011).

Resistance to shoot fly in sorghum is expressed in terms of oviposition non-preference, antibiosis and

tolerance (Dhillon et al 2005a). However, the factors influencing these mechanisms have not been

identified in the promising maize cultivars for spring season in the Punjab. To develop crop cultivars with

durable resistance to insect pests, it is important to identify germplasms with diverse combinations of

factors associated with resistance to the target pests and then to combine identified

components/mechanisms of resistance in the same genetic background. Some of the factors associated

with resistance to insects can be quantified or monitored easily in plant populations and such characters

can be used as "marker traits" to screen and select for resistance to insect pests (Chamarthi 2008).

There is a need to develop integrated pest management (IPM) strategies involving cultural

methods of management of shoot fly spp. in spring season. But it requires a thorough knowledge of the

life history, behaviour and ecology of the insect as well as of its plant or animal hosts. The most

vulnerable stage (s) in the life cycle must be determined to develop practices to lessen its attack, to kill it,

or to slow down its rate of reproduction (Lawani 1982). The principle of controlling insect pest

populations by increasing the diversity (Solomon 1973)can successfully be employed by using sorghum


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as a trap crop, which had been reported as a preferred host for egg lying by shoot fly (Ogwaro 1978,

Sarup et al 1986). The low humidity increased the duration of egg development and decreased the egg

survival; and continuous rainfall reduced shoot fly abundance (Raina 1981, Delobel 1983, Taneja et al

1986). These facts can be exploited by standardization of irrigation frequency and evaluation of sorghum

as trap crop for management of shoot fly during spring season in the Punjab.

Keeping in view the above facts, the present studies on incidence of insect pests and

management of shoot fly, Atherigonaspp. in spring sown maizewere undertaken with the following

objectives:

Objectives:

a) To study the populations build up of insect pests and their extent of losses in spring maize.b) To establish the morphological and biochemical bases of resistance against shoot fly in different

promising cultivars.

c) To formulate integrated approaches for management of shoot fly in spring sown maize.


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Chapter-II

REVIEW OF LITERATURE

The literature of previous years recorded 160 insect and mite species on maize crop (Pant and

Kalode 1964), but afterwards Mathur (1987) observed over 250 species of pests associated with maize in

field and storage conditions. Siddiqui and Marwaha (1994) reported 139 insect pests causing varying

degree of damage to maize crop from sowing to harvest. They further reported that only about a dozen of

these are quite serious and require control measures. Insect pest complex changes in time and space. The

crambid, Chilo partellus (Swinhoe) and muscids, Atherigonaspp. are of major production constraint in

maize cultivation in north India during different seasons (Kumar et al2005). The present studies were

undertaken on various aspects of shoot fly, Atherigona naqviiSteyskal to formulate appropriate strategies

for its effective managementand to estimate loses due to insect pests in spring sown maize in the Punjab.

The relevant literature pertaining to different aspects of shoot fly, Atherigonaspp. management and other

insect pests has been reviewed under the following headings:

2.1 Prevalence of shoot flies,Atherigonaspp.

2.2 Geographic distribution and host range of shoot fly,A. naqvii

2.3 Bioecology of shoot fly,A. naqvii

2.3.1 Nature of Damage ofAtherigonaspp.

2.3.2 Ovipositional preference ofAtherigonaspp. under field conditions

2.3.3 Effect of sowing time on the incidence ofAtherigonaspp.

2.4 Host plant resistance for the management of shoot flies,Atherigonaspp.

2.4.1 Evaluation of germplasm againstAtherigona spp.

2.4.2 Mechanisms of host plant resistance toAtherigona spp.

2.4.2.1 Antixenosis for oviposition

2.4.2.2 Antibiosis

2.4.2.3 Tolerance

2.4.3 Bases of resistance toAtherigona spp.

2.4.3.1 Morphological plant traits

2.4.3.2 Biochemical plant traits

2.5 Management of shoot fly,Atherigonaspp.

2.5.1 Management ofAtherigona spp. with insecticide

2.5.2 Management ofAtherigona spp. with non-chemical methods

2.6. Other insect pests of spring maize


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2.1 Prevalence of shoot flies, Atherigonaspp.

Shoot fly was first noticed infesting maize at Pantnagar in spring season during 1967 (Rathore et

al1969) and the reared flies were identified as Atherigona orientalisSchiner.Atherigona naqviiSteyskal

was observed attacking maize crop in the Punjab in 1972 (Sandhu and Kaushal 1976) with report of more

than one type of eggs on maize plant. Sixteen shoot fly species namely, Atherigona bidensHenning,A.

falcata Thomson,A. naqvii, A. orientalis, A. punctataKarl, A. soccataRondani, A. oryzae Malloch, A.

vorkif Deeming, Anacamptoneurum obliquum Becker, Anatricus erinaceus Loew, Aprometopis

flavofacies Becker, Delia arambourgi (Seguy), Elachiptera scapularis (Adams), Lasiosina sp.,

Scoliophthalmus micantipennis Duda and S. trapezoids Becker have so far been recorded on maize in

Africa and Asia (Panwar and Sarup 1985) including six species A. bidens, A. falcate, A. naqvii, A.

orientalis,A. punctataandA. soccataare from India. A. orientalisoccurred inPantnagar (Rathore et al

1969).A. soccata is a serious pest of sorghum in kharif(monsoon) season (Jotwani et al1970) whereas,

A. naqviiattacks barley (Srivastava et al1969) and wheat (Kundu and Kishore 1971). A. naqviiandA.

soccataare serious pests in northern India (Sandhu and Kaushal 1976, Sarup et al 1984).A. soccata, A.

bidens, A. falcata andA. punctata occur occasionally in the southern region (Seshu Reddy and Davies

1977, Davies and Seshu Reddy 1981). However, A. naqvii, invading spring sown maize, is of a serious

concern for the farmers in the Punjab.

2.2 Geographic distribution and host range of shoot fly, A. naqvii

A. naqvii has been reported from India (Delhi, Kerala, Uttar Pradesh, Rajasthan and Punjab),

Ceylon, Australia, Nigeria, Pakistan, Ethiopia, Saudi Arabia and South Africa (Panwar 2005). Its host

plants include Triticum aestivum Linn. ( Ramachandra Rao 1924, Srivastava and Pandey 1968, Pont

1972); Hordeum vulgare Linn. (Srivastava et al 1969); Arundinella metzii Hochst ex. Miq., Digitaria

sanquinalis(Linn.) Scop andPennisetum typhoides(Burm.) (Pont 1972);Zea maysLinn. (Deeming 1971,

Pont 1972, Sandhu and Kaushal 1976) andAvena ludoviciana Linn. (Singh and Khan 1980).

2.3 Bioecologyof shoot fly, A. naqvii

A complex of Atherigonaspp. cause severe losses in spring sown maize in northern India. Two

major shoot fly species viz., A. soccataandA. naqviiproduce similar type of dead hearts. However, the

difficulty in identification of shoot fly species on the basis of type of damage can be overcome by its site

of oviposition and distinguishing characters of eggs of both the species. The eggs of A. soccataare laid

singly on the underside of sorghum leaf almost parallel to mid rib, whereas that ofA. naqviiare laid either

in soil in cracks or crevices (around maize seedlings) or at the base of stem/under surface of lower leaves

of other cereals (Kishore 1991). In case of A. soccata, the egg is elongated with hexagonal sculpture


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giving an appearance of reticulation whereas that of A. naqvii is cylindrical in shape and marked by

reverse dichotomous lines running somewhat parallel (longitudinally) from one end to the other. The egg

distribution by bothA. naqviiandA. soccatais random or slightly aggregated rather than regular (Delobel

1981 and Hari et al2013). The ovipositional behaviour of shoot fly species did not have any effect on its

damage on varieties having different plant population levels in spring sown maize (Rao and Panwar

1994). The incubation period ofA. naqvii eggs is 1 to 3 days. The freshly hatched larva is dirty white and

full grown larva is yellow in colour. On hatching, the maggot feeds on leaf surface in funnel primarily as

whorl maggot and attacks the growing point. The maggot is full grown in 15-18 days. The pupal period

lasts for 8-9 days. The adult longevity was 1-2 weeks when reared on yeast glucose dry food (Sandhu and

Kaushal 1976).The total life cycle of A. naqvii on maize was completed in 17-33 days (Kumar and

Chander 1987).

2.3.1 Nature of Damage of Atherigonaspp.

The Atherigona spp. causes damage at seedling stage of the crop. The newly emerged maggots

enter the leaf whorl by crawling along the leaf sheath, move downwards by feeding on plant tissues which

results in the browning of the central axes and gradual drying up of the growing points form the

deadhearts in the young plants. However, the older plants do not show dead hearts but the damaged leaves

of such plants get interwoven with central leaf and show curling and distortion. Irregular slits and

deformed leaves are formed as a result of attack (Sarup et al1984, Kanta et al 2006). Raina (1981) found

that very little damage is done to the growing point by the first instar and the deadheart is caused by

cutting the base of the central shoot. The first and the second instars are mainly involved in cutting of leaf

tissues, whereas the third instar feeds on dead and decaying tissues. Sajjan and Sekhon (1985) reported

that the shoot fly complex produced upto 85.8 per cent dead hearts in spring sown maize in Punjab.

Gagandeep and Kanta (2007a) reported that under natural conditions the protected maize crop, in spring

season of 2004, yielded 11.78 q per ha, with subsequent reduction of yield by 16.46, 22.41, 29.79, 34.88,

40.66, 44.22 per cent in the treatments plots with 5, 10, 20, 30, 40 and 50 per cent deadhearts incidence,

respectively. They further reported that a delay of 15 days in control practices resulted into yield losses to

the tune of 32.4 per cent.


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2.3.2 Preferential plant age and site for oviposition by Atherigonaspp. in the field

The egg laying byA. soccatais random in field (Delobel 1981). The observations on preferential

plant age and site for oviposition byA. soccataandA. naqviiunder field conditions at different locations

for two years made by Sarup and Panwar in 1987 on spring maize revealed that in both the years,

regardless of the site of oviposition, the maximum number of eggs were laid on 9 to 11 days old plants.

Significantly more number of eggs were laid on/in the soil around each plant (in cracks and crevices) than

those laid on the foliage, established the dominance of A. naqvii over the A. soccata. However, no

significant difference either in the eggs laid or in the deadheart formation due to shoot fly species was

obtained at various locations in the field.

2.3.3 Effect of time of sowing on the incidence of Atherigonaspp. in spring sown maize

The most practical control method of Atherigona spp.is the choice of a sowing date that enables

the crop plants to pass the susceptible stage at a period when its density is low (Jotwani et al1970). The

investigation on the effect of date of sowing on shoot fly incidence, not only pinpoints the period of its

maximum activity, but also helps in adjusting the sowing date of the crop to escape the period of high

incidence of the pest in the field. During 1970-71 at Pantnagar, the number of shoot fly eggs as well as

deadhearts were recorded as maximum in the crop sown in the 3 rdweek of February than that in the 1st

and 2ndweek of February. Thus it could be deduced that in teraiarea of Uttar Pradesh, the early sown

maize crop i.e., sown during 1st and 2nd week of February, escapes shoot fly incidence. The delay in

sowing might attract shoot fly incidence with consequential losses in yield (Sarup et al1979). The peak

period of activity of A. soccata and A. naqvii was reported from 3rdweek of February to 1st week of

March at Indian Agricultural research Institute, New Delhi, on the basis of number of eggs laid and

deadhearts produced by them (Marwaha et al1984). Two maize cvs Deccan 105 and Kiran were sown on

six sowing dates viz., 8th, 15

th, 22

nd, 29

thMarch, 5

thand 12

thApril in 1993 at Delhi to observe the peak

period of shoot fly activity during spring season. But in respect of egg laying, the shoot flies did not show

any preference to any of the two varieties sown on different dates. The maximum and minimum

deadhearts incidence of 17.9 and 6.6 per cent was observed irrespective of varieties, on the crop sown on

8thMarch and 6thApril, respectively. However, maximum number of eggs (6.28/ plant) was observed in

crop sown on 22nd March (Rao and Panwar 1995a). Singh and Kanta (2004) on the basis of two years

study (in 1999 and 2000) at Ludhiana reported comparatively more incidence of shoot fly on crop sown in

mid February than that sown in March and April. Gagandeep and Kanta (2007b) in another study on

influence of date of sowing on incidence of A. naqvii on maize reported that A. naqvii produced

maximum damage of 25.77 per cent dead hearts on 6 th March sown crop. They further reported that

among different dates the deadhearts incidence varied from 2.33 to 12.83, 2.63 to 12.67, 17.64 to 33.90


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and 13.50 to 17.60 per cent under protected and unprotected conditions, on crop sown on 15 th, 25th

February, 6th and 16th March, respectively. The maximum pooled grain yield (9.46 q/ha) over

protected/unprotected conditions was obtained from the crop sown on 15th February and mean yield of

crops sown at different dates was significantly higher under protected conditions (11.36 q/ha) than that in

unprotected conditions (4.75 q/ha).

2.4 Host plant resistance for the management of shoot flies, Atherigonaspp.

Host plant resistance to insects is one of the easiest and cheapest components of an integrated

pest management programme. It is an environmentally safe method of pest management, and is

compatible with other control strategies such as biological, cultural and chemical control (Smith 2004).

Host plant resistance is one of the most effective means of keeping shoot fly population below Economic

Threshold Levels, as it does not involve any cost input by the farmers. Plant resistance to shoot fly

appears to be complex character and depends on the interplay of number of componential characters,

which finally sum up in the expression of resistance to shoot fly (Dhillon 2004).

2.4.1 Evaluation of germplasm to Atherigona spp.

Germplasm evaluation in maize for reaction toAtherigonaspp. has been carried out under natural

infestation only. The fish-meal technique (Nwanze 1997) is quite useful for increasing shoot fly

abundance for screening the test material under field conditions. The moistened fish-meal is applied @ 50

g per m2one day after seedling emergence by broadcasting in the field to screen maize germplasm (Jindal

et al 2007). Among the various forms of shoot flies damage, the evaluation of germplasm is done by

counting the deadhearts produced by them. The deadheart count is considered easy, quick and useful

criteria for assessing the relative reaction of genotypes as it gives approximate idea about the total loss of

plant population and yield (Sharma and Singh 1975). The 19 ratings scale for scoring shoot fly species

damage in maize was given by converting percentages of the dead hearts due to shoot fly into the rating

scale (Sharma et al 1992). The detail of rating and description is as 1 = < 10 %, 2 = 1020 %, 3 = 2130

%, 4 = 3140 %, 5= 4150 %, 6 = 5160 %, 7 = 6170 %, 8 = 7180 %, 9 > 80 % deadhearts. The plants

having only leaf injury, generally, show remarkable recovery (Sekhon et al 1993).

To confirm the resistance to shoot fly observed under field conditions and to study the resistance

mechanisms involved in host plant resistance to sorghum shoot fly, A. soccata in sorghum a cage-

screening technique was developed by Soto (1972). The technique was modified at International Crops

Research Institute for the Semi-Arid Tropics (ICRISAT) to simulate field conditions more closely and has

the advantage of requiring no artificial rearing of shoot flies (Taneja and Leuschner 1985). Shoot flies

used for cage screening are collected from a trap baited with fishmeal. The cage screening technique can


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be used for multiple as well as no- choice conditions. Such technique is not in use for screening of maize

genotypes againstA. naqviiin India.

In India, up till now about 2000 maize germplasm lines have been screened against Atherigona

spp. and number of resistant sources has been identified by various workers from different locations

(Siddiqui et al 1988, Panwar 2005, Kumar and Kanta 2011). On the basis of deadhearts by shoot fly,

maize germplasm with white semiflint br pop, white semiflint br pop-2 and D-37 were categorized as

least susceptible while, early white composite and Romanian flint proved to be highly susceptible

(Sharma and Singh 1975). Among forty two maize germplasms comprising of some locals, elite material

and single cross hybrids tested under heavy natural incidence of shoot fly complex in spring season the

percentage of deadhearts varied from 34.8 to 82.6, with Lakshmi composite from Bihar and Khevawal

local 2 from Punjab were relatively less susceptible (Marwaha et al 1986). Sarup and Panwar (1986)

reported tolerance to shoot fly in maize germplasm in different maturity groups. In another germplasm

evaluation study Sharma and Panwar (1998) found that deadhearts percentages in different germplasms

varied from 23.0 to 83.6 per cent and tolerant lines belong to early maturity group. The judicious

utilization of less susceptible lines to both maize borer and shoot fly in resistance breeding can immensely

help in developing maize cultivars resistant to pests possessing other desirable agronomic traits (Panwar

and Sharma 1998). Continuing the process of identifying the resistant lines to shoot fly in maize Panwar

(1995) reported that among the twenty seven elite maize germplasms tested, the deadhearts percent

ranged from 5.0 to 24.2 and the four lines EH 40428, HYD 8275, SSM 5010 and MMH 41 were found to

be tolerant for incorporation in future breeding programmes. Multiple pest resistance in cultivar Diara

EV and in two inbred lines (IPA 34-10-13-3-1-1-#-2-1 and IPA 3-6-14-2-#-1) to the shoot fly species and

maize borer was observed by Panwar and Sarup (1988) and Panwar et al (2000), respectively. Similarly

multiple resistance to maize borer and shoot fly in four genotypes EV5098, EV 6098, Agaiti 2002 and EV

1098 at Sahiwal in Pakistan was reported by Shahzad et al(2006). Jindal et al (2007) reported maize

hybrids PMH 1 (8.53 %) and JH 3459 (11.03 %) as less susceptible on the basis of deadhearts formation

in comparison to Parkash (25.36 %) and PMH 2 (24.95 %) to shoot fly in spring maize in the Punjab.

Among inbreds tested, CM 143 was found to be tolerant (16.24 %) while the highest incidence was

highest (46.32 %) on CM 144.

2.4.2. Mechanisms of resistance

All the three major mechanisms of resistance viz, oviposition non-preference (antixenosis),

antibiosis, and recovery contribute to host plant resistance to sorghum shoot fly, A. soccata(Soto 1974,

Raina et al1981, Taneja and Leuschner 1985, Sharma et al1997, Dhillon et al 2005a, 2006). However,


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with respect to maize, a few reports are available on oviposition and tolerance but scanty information is

available in the literature elucidating the mechanism of antibiosis for plant resistance toA. naqvii.

2.4.2.1 Antixenosis for oviposition

Non-preference by insects is often projected as a property of the plant to render it unattractive foroviposition, feeding or shelter. Non preference for oviposition is considered to be a primary mechanism

of resistance to shoot fly in sorghum (Singh and Jotwani 1980a, Singh et al1995). Behavioral responses

of shoot fly,A. soccatain sorghum have shown that initial choice of the host was random, but the females

spent less time on the resistant cultivars (Raina et al1984). Females laid eggs on non-preferred cultivars

only after laying several eggs on the seedlings of susceptible cultivar in sorghum. However, according to

Dhillon et al (2005a) this mechanism of resistance was not stable and tended to breakdown under no-

choice conditions. The varying preference for oviposition by shoot fly (Atherigonaspp.) was reported and

different maize germplasms were grouped on the basis of number of eggs laid per plant at Pantnagar

(Sharma and Singh 1975). However, no difference in discriminating plants of various maize germplasms

for oviposition byAtherigonaspp. was reported by subsequent workers (Sarup and Panwar 1986, Panwar

and Sarup 1988, Rao and Panwar 1996a). Similarly, Rao and Panwar (2001a, 2001b) reported that none

of the morphological and biochemical plant characters influence egg laying by shoot fly in field on maize.

Seven maize cultivars viz., Antigua Gr.I, Deccan 103, Kiran, Ganga 11, Deccan 105, Pusa composite 1

and CM 300 were evaluated againstAtherigonaspp. under natural infestation conditions. Over number of

years it was observed thatAtherigonaspp. did not discriminate for egg laying on 9-11 day old plants of

different varieties. Jindal et al(2007)reported that among the different genotypes tested at Ludhiana, JH

3980 was the least preferred genotype for oviposition by shoot fly. However, there was no significant

difference in egg laying in susceptible PMH 2 and moderately resistant hybrid JH 3459.


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2.4.2.2 Antibiosis

The resistance to sorghum shoot fly is a cumulative effect of non-preference and antibiosis (Raina

et al 1981). Retardation of growth and development; prolonged larval and pupal periods; and poor

emergence of adults on resistant genotypes provide an evidence of antibiosis to sorghum shoot fly

(Sharma et al 1997). Sharma and Singh (1975) reported that some genotypes in maize, more preferred for

oviposition, had lesser average number of surviving maggots per plant indicating the role of antibiosis in

different germplasms. The shoot fly maggots fed on resistant sorghum cultivars i.e. SFCR 151, ICSV 705,

SFCR 125 and IS 18551 exhibited longer larval period (10.111.0 days), lower larval survival (54.767.8

%) and adult emergence (46.752.2 %) than on susceptible check Swarna i.e.9.3 days, 73.3 and 60.6 %,

respectively (Dhillon et al 2005a). Singh and Narayana (1978) reported that the fecundity of shoot

fly females was greater when raised on susceptible check variety Swarna, than that on moderately

resistant varieties IS 2123 and IS 5604 However, reverse trend was observed by Dhillon et al(2005a).

2.4.2.3 Tolerance

Seedling vigour and high rate of recovery of sorghum are important characteristics of resistant

cultivars to shoot fly (Sharma et al 1977). Maize germplasms vigorous in growth in the early growth

stage showed lower percentage of deadhearts and it might be due to quick recovery of plant from the

injury by shoot fly maggot or coming out of maggots along with the extended leaves during the quick

growth of plants (Sharma and Singh 1975). The differences in increase of deadhearts in subsequent

observations among maize germplasms were due to their relative capacity to withstand or recover from

the shoot fly damage (Pandey and Sharma 1980). Patel and Sukhani (1990) reported negative correlation

of plant height and stem length with oviposition and deadhearts by shoot fly in sorghum, suggesting that

the pest resistant plants grew faster and might therefore escape the damage. The significantly higher plant

height in infested plants of less susceptible maize cultivar JH 3459 (116.9 cm) than the susceptible

cultivar PMH 2 (76.3 cm) vis-a-vis non significant difference in height of healthy plants of these

genotypes indicates tolerance in less susceptible hybrid. The lowest reduction in height (33.2 %) and

grain weight per plant (38.7 %) in infested plants due to Atherigona spp. over healthy plant was also

observed in hybrid JH 3459 (Jindal et al2007). This supports the idea that the resistance to shoot fly in

maize is primarily dependent on the degree of tolerance.


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2.4.3 Bases of resistance to Atherigona spp.

Plant resistance toAtherigonaspp. is a complex character and depends on the interplay of number

of componential characters, so it is important to identify genotypes with different mechanisms to increase

the levels and diversify the bases of resistance to this pest. A diverse array of plant characteristics may

influence its resistance/susceptibility toAtherigona spp.

2.4.3.1 Morphological plant traits

Plant morphology can have a strong impact on shoot fly population dynamics, especially in case

of seedling characteristics that physically reduce feeding, oviposition and shelter.

Faster seedling growth and toughness of the leaf sheath are associated with resistance to shoot fly

in sorghum (Singh and Jotwani 1980b). Jayanthi et al(2002) showed that shoot fly resistant parental lines

and their hybrids showed significantly high seedling vigour compared to susceptible parental lines and

their hybrid groups. The negative correlation between seedling vigour with egg counts and deadheart

formation was reported by Kamatar and Salimath (2003) in sorghum.

Trichomes or plant hairs are common anatomical features on leaves, stem and/or reproductive

structures in higher plants. Levin (1973) had described the role of trichomes in plant defense and pointed

out that in numerous species, there is negative association between trichome density and insect feeding,

oviposition responses and nutrition of larvae. The trichome density has a positive correlation with

resistance toAtherigonaspp. in maize. TheAtherigonaspp. resistant varieties of maize possessed higher

trichome density on leaves (Rao K R and Panwar, 1995b). In sorghum also, number of eggs per plant and

per cent plants with eggs were negatively correlated with trichome density when observed 14 days after

emergence (Patel and Sukhani 1990, Dhillon et al 2005a). Karanjkar et al(1992) suggested that although

there are highly significant negative correlation between the trichome density and shoot fly infestation,

yet it seems that trichomes do not have a direct role in reducing the deadhearts, but are associated with

reduced oviposition and can be used as a reliable selection criterion to select germplasm for resistance to

shoot fly.

The leaf glossiness (pale green and shiny leaves) at seeding stage probably has a strong influence

on the orientation of shoot fly, A. soccata females due to reflection of light in sorghum. The genotypeswith high leaf glossiness are resistant to shoot fly (Dhillon et al2005 a,b).

The leaf surface wetness (LSW) i.e. the role of morning dew in the movement of freshly hatched

shoot fly,A. soccata larvae through the leaf sheath to the growing point in sorghum was first studied by

Rivnay (1960). Nwanze et al (1990) reported that LSW is associated with shoot fly resistance in sorghum

which was reported to be more in 10-day old seedlings than seedlings of other ages. Larval survival is


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affected by the wetness of the central shoot and initial contact of larva with moisture enhances its

movement and survival (Nwanze et al 1992).

The taller varieties with more leaves are desirable for minimizing the shoot fly incidence. Rao

and Panwar (2001a) reported that the leaf width and stem thickness were positively associated where as

the number of leaves per plant and leaf length were negatively associated with shoot fly deadhearts in

maize. However, there was no significant influence of these plant characters on the oviposition. Singh and

Jotwani (1980b) reported that in sorghum, the leaves of resistant varieties are narrower and longer than

the susceptible ones. The rapid seedling growth; and long and thin leaves during the seedling stages make

plants less susceptible to shoot fly attack (Singh 1998).

The oviposition by shoot fly in sorghum was negatively correlated with seedling height, leaf

length and stem length, but positively correlated with number of leaves per plant, leaf width, stem girth,

and panicle initiation. However, deadhearts produced by shoot fly were negatively correlated with

seedling height, leaves per plant, leaf length, leaf width, and stem length and positively correlated with

stem girth and panicle initiation (Verma and Singh 2000).

The green colour leaves with rough surfaces were more preferred for egg laying byA. soccata

(Raina 1982). Similarly, Patel and Sukhani (1990) reported the positive correlation between seedling

weight at 20 DAG and leaf colour with shoot fly damage in sorghum and suggested that healthy and stout

seedlings with dark green leaves are more preferred for egg laying resulting in higher deadhearts

incidence. The plumule and leaf sheath pigmentation in sorghum were found to be associated with

resistance to shoot fly (Dhillon 2004, Dhillon et al 2005 a, b).

2.4.3.2 Biochemical plant traits:

The literature reviewed identified only a few deliberate screening programmes for identification

of the role of biochemical components in imparting resistance to A. naqvii on maize. But, a lot of

information is available on the role of biochemical constituents imparting resistant to related species A.

soccata on sorghum. Plant resistance is attributed largely to secondary metabolites such as phenolics,

nonprotein amino acids and alkaloids, which are documented to be deleterious to insect herbivores

(Manuwoto and Scriber 1985, Wang et al2006).Plants are known to produce certain chemical compounds

in different quantities and proportions, which affect the behavior and biology of phytophagous insects

(Painter 1958, Beck 1965, Schoonhoven 1968), and can be attractants (oviposition and feeding

stimulants) or repellents (oviposition and feeding deterrents) or antibiotic (reduced survival, growth, and

fecundity). Cultivars that lack these defense mechanisms are often too vulnerable to damage of insect

pests. An important group of defense chemicals in maize host plant resistance to corn earworm is


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consisted of secondary metabolites C-glycosyl flavone maysin and the phenylpropanoid product

chlorogenic acid in silk. The first brood of the European corn borer ( Ostrinia nubilalis) is controlled by

high levels of the benzoxazinoid DIMBOA in seedlings and young plants (Klun et al 1970). These

secondary metabolites are produced independent of the presence of the pest in a tissue and develop in a

specific manner. In addition to secondary metabolites, ubiquitous phenolic acids, especially ferulic acid,

may contribute to insect resistance in maize (McMullen et al2009).

Resistance toAtherigona spp. and C. partellus in maize (Rao C N and Panwar 2001b, 2002), and

sorghum shoot fly in sorghum (Mote et al 1979, Kamatar et al 2003) is associated with low levels of

proteins. Kabre and Ghorpade (1999) indicated that protein content was positively correlated with stem

borer susceptibility in maize, while such relationship between free amino acid content and stem borer

susceptibility was not evident.

The maize plants with resistance to spotted stem borer, C. partellus had low amounts of sugar

(Sekhon and Kanta 1994). Similarly Kabre and Ghorpade (1999) reported that total and reducing sugars

were positively correlated with stem borer susceptibility in maize. The slight increase and decrease in

reducing sugars between 17 and 20 days after seedling emergence in shoot fly resistant sorghum

genotypes and susceptible varieties, respectively was reported by Bhise et al(1997). However, Singh et al

(2004) reported that resistance to shoot fly is associated with low levels of reducing and total sugars in

sorghum seedlings. Development of sugarcane aphid, Melanaphis sacchari (Zhent.), and delphacid,

Peregrinus maidus (Ashm.) populations were more pronounced in varieties with higher sugar content in

leaves (Mote and Shahane 1994). However, soluble sugar content had little influence on midge,

Sitodiplosis mosellana(Gelin.) resistance in wheat (Shi ZhongLiang et al 2002).

Tannins are polymers resulting from condensation of flavan-3-ols. The significant and

negative correlation between tannin content and shoot fly damage was reported by Chamarthi (2008). Shi

ZhongLiang et al(2002) reported that tannins are important secondary metabolites for induced resistance

to blossom midge in wheat.

Polyphenols are widely distributed in plants, but they are not directly involved in any metabolic

process and therefore, are considered to be secondary metabolites. Phenolic compounds in maize are (E)-

ferulic and (E)-p -coumaric acid which are attached to hemicellulose through pentose sugars . Theplant

phenolics have attracted great interest in relation to their diversity in chemistry; and functionality in

biology, chemistry, medicine, ecology and agriculture. In agriculture, they have long been recognized as

allelochemicals (Rice 1984), and constitutive and induced plant defense mechanisms (Vidhyasekaran

1988).


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alterations in biochemical constituents in mulberry after infestation with leaf roller, Diaphania

pulverulentalis(Hampson) were reported by Mahadeva and Negaveni (2011).

2.5 Management of Atherigonaspp.

2.5.1 Management of Atherigonaspp. with insecticide

The just emerged maize seedlings suffer extensive damage leading to deadhearts formation by

shoot fly species. Since, the adult of shoot flies oviposit on the emerging seedlings and in cracks and

crevices around the seedlings (Kishore 1991), the plant protection measures at early seedling stage are

essential to protect the crop from their severe infestations. Earlier application of a number of systemic

granular insecticides in the furrows at the time of sowing has been reported to give good results against

this pest (Chatterji et al 1973, Panwar et al 1999a). However, foliar sprays were not effective against

shoot flies (Sharma et al1979) in spring sown maize. The seed treatment with carbofuran 40F @ 10 g per

100 g of maize seed was found to be most effective for controlling A. naqvii at Ludhiana. The soil

application of carbofuran 3 G @ 12.5 kg and phorate 10 G @ 10.0 kg per hectare at sowing time was also

found to be effective against this pest at same place (Sajjan and Sekhon 1985, Kanta et al2006). The seed

treatment with 1.5 % carbofuran 35 ST or 25 ST or 1.0 % furathiocarb 40 SD or furrow application of

carbofuran 3 G (0.375 kg a.i./ ha) and phorate 10 G (1.25 kg a.i./ ha) was most effective in reducing the

deadheart formation due toAtherigonaspecies in spring sown maize. Further more, the foliar application

of synthetic pyrethroids and insect growth regulator chlorfluazuron (PP 145) also showed significantly

less number of deadhearts vis--vis control but these were comparatively less effective than the above

insecticides (Marwaha et al1985, 1987). The effectiveness of dimethoate, monocrotophos, phosalone @

0.1 % and @ 0.05 % chlorpyriphos reduced the formation of deadhearts due to shoot fly species. The

spraying and dusting of maize crop at the seedling stage did not deter the shoot flies from ovipositing on

the treated maize leaves or in the cracks and crevices in soil around the maize seedlings (Sinha 1989).

Rao and Panwar (1992) evaluated the efficacy of carbofuran 3G, carbosulfan 25 STD,

3% neem kernel suspension, neem oil 20 EC, mohua oil 20 EC and phorate 10 G against shoot fly in

spring sown maize and reported that average incidence of deadhearts was least in plots treated with

phorate 10 G (8.82 %) and was highest in plots treated with neem oil (45.62 %). The plant products were

not found effective to protect the crop against the ravages of shoot fly species in spring sown maize. The

shoot fly did not discriminate between different treatments for egg laying. The effectiveness of maize

treated seed with carbosulfan 25 STD @ 20 g and 40 g per kg seed, stored for different periods; and

mixture of treated (60 %) and untreated (40%) maize seeds was also reported to be effective against

shoot fly by Rao K R and Panwar (1995c, 1995d). Among different treatments i.e. application of

carbofuran (slow release) 5 G @ 0.5 and 1.0 g m-1 row and carbofuran 3 G @ 1.0 g m-1 row; PEG-phorate


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10 @ 0.25 g m-1 row and phorate 10 G @ 1 g m-1 row; and seed treatment with imidacloprid 70 WS @

5.0, 7.5 and 10.0 g kg-1seed significantly reduced deadheart formation in spring sown maize. However,

shoot flies did not discriminate amongst the plants in different treatments for egg laying in the field (Rao

K R and Panwar, 1996 b). The spot treatment by pinch application of Marshal 6 G (carbosulfan), Furadan

3 G (carbofuran) and Thimet10 G (phorate) proved effective in reducing incidence ofA. naqviiin summer

maize (Singh and Kanta 2006). The effectiveness of seed treatment with thiamethoxam 70 WS @ 2 g per

kg seed of sorghum in reducing dead hearts incidence was reported by Kumar and Prabhuraj (2007). In

spring sown maize at Ludhiana, Jindal and Hari (2008a) reported high effectiveness of seed treatment

with imidacloprid 70 WS @ 5 g per kg seed in reducing dead heart incidence (3.42 %) by A. naqviias

compare to untreated control (70.03%) and carbofuran 3G application (13.59%). The foliar application of

endosulfan 35 EC @ 200 ml per acre was also reported to be at par with granular insecticide applications

in controlling the shoot fly (Hari and Jindal 2008). The improved formulation of imidacloprid (Gaucho)

600 FS @ 6 and 9 ml per kg seed was more effective in reducing deadhearts due to attack of A. naqvii

(5.41 and 8.99 %, respectively), whereas the formulation of thiamethoxam (Cruiser) 70 WS @ 3.0 and 5.0

g per kg seed with (17.02 and 15.10 % deadhearts, respectively) was less effective (Jindal and Hari 2011).

2.5.2 Management of shoot fly with non chemical methods

The more emphasis has been given on chemical control of shoot flies and is often being adopted

by the farmers. The indiscriminate use of insecticides causes environmental pollution, residue problems,

development of resistance, pest resurgence, secondary pest outbreaks and destruction of natural enemies

of the pest. So, there is need to develop IPM strategies involving cultural methods of pest control for the

management of shoot fly species in spring season. But it requires a thorough knowledge of life history,

behaviour and ecology of insect as well as of its plant or animal hosts. The most vulnerable stage (s) in its

life cycle must be determined and the practices be developed to prevent attack by the insect, to kill it, or

to slow down its rate of reproduction (Lawani 1982).

Inter-cropping of maize for the control of Atherigonaspp.

The principle of controlling insect pest populations is by increasing the diversity of an agro-

ecosystem. It is crucial, however, that the right kind of diversity be established (Smith 1970). Under

choice test for oviposition, sorghum shoot fly markedly preferred Sorghum bicolor than other

graminaceous plants species i.e. Digitaria scallarum, Rottboellia exaltata, Setaria verticillata and

Panicum maximum(Ogwaro 1978). Raina and Kibuka (1983) reported that in intercrop field trials 6 and

61 per cent eggs of shoot fly, A. soccataeggs, were received by maize and sorghum plants, respectively.

Sarup et al(1984) reported higher per cent dead hearts in sorghum due to shoot fly species as compared

to maize irrespective of sowing dates in spring season. The peak activity of shoot fly species exhibited in


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maize sown on 16thmarch was at par with the lowest activity in sorghum planted on 30 thMarch. Almost

cent per cent deadhearts were produced in sorghum in the early three sowings implaying that peak activity

of shoot fly in spring sown maize and sorghum was unrelated. The polyphagous nature of shoot fly

species invading the spring sown maize led to suggestion of possible exploitation of this habit to control

damage in maize fodder by providing a trap of most suitable host sorghum (Sarup et al1986). Subsequent

evaluation of Sorghum planting in different permutation and combinations (5-35 per cent) along with

maize was unworkable in spite of varied intensities of shoot fly infestation. The per cent deadhearts in

maize in different years (1984-86) varied from 1.1-2.4, 24.8-37.9 and 56.4-7.12 with corresponding figure

of 68.0-76.0, 87.5-100.0 and 94.6-98.9 in sorghum. There was simultaneous occurrence of both A.

soccataandA. naqviiin spring maize seedlings as against only A. soccatadamaging sorghum seedlings

perhaps masked the overall effect of preferred host sorghum. The oviposition byA. naqviisoon after the

emergence of maize seedlings at 2-3 leaf stage restricted the success of sorghum as trap crop (Sarup et al

1986). Maize was inter-cropped with sorghum, bajra, cowpea and soybean for the control of shoot fly

species in spring 1993 season at Delhi. There was no significant effect of egg laying or dead heart

formation in maize due to shoot fly species when maize was inter-cropped with other millets and pulses.

On the other hand, inter-cropped sorghum received significantly more eggs per plant and dead heart

formation due to shoot fly species visvis other inter cropped crops with no egg laying or deadheart

formation in unrelated hosts i.e. soybean and cowpea. The lowest per cent deadhearts were recorded in

maize + soybean intercropping. More deadhearts (24.7 %) formed in maize intercrop with sorghum

proved that it was not useful in management of shoot fly (Rao K.R. and Panwar, 1995 e).

Effect of weather factors on incidence of Atherigonaspp.

The temperature and humidity influenced the development of the eggs, 30 oC and 90 per cent

relative humidity (R.H.) being the best combination, for the development of shoot fly, A. Soccata as

reported by Doharey et al (1977). On wheat, A. naqvii was more active from the second fortnight of

October to end December; and again during February and March. These fluctuations appear to have a

positive correlation with maximum and minimum temperature while the relative humidity and the rainfall

did not have any influence on activity ofA. naqvii (Khan and Singh 1980). The egg hatching inA. soccata

coincides with the presence of moisture on the leaf (Raina 1981). Low humidity (30%) increased the

duration of egg development and decreased the egg survival. Temperatures above 350

C and below 180

C

and continuous rainfall reduce the shoot fly abundance(Delobel 1983, Taneja et al1986). Marwaha et al

(1984) found that average maximum temperature ranging from 27 to 30oC and minimum 12-15

oC coupled

with higher relative humidity between 75-80 per cent and some rainfall in the last week of February with

sporadic drizzling in March were conducive toAtherigonaspp. activity in terms of higher oviposition and


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deadhearts formation. These aspects can successfully be utilized for the management of shoot fly. Naitam

and Sukhani (1989) reported that more soil moisture and temperature results into lesser shoot fly damage

and increased sorghum. Sekhon et al (1986) reported that winter maize crop, sown on southern face of

ridges, suffered significantly less damage than that sown as flat and on northern face of the ridge due to

more rapid and vigorous growth of maize plants, which is attributed to the prevalence of relatively higher

temperature during day time on southern side of ridges. Similar observation was made on spring sown

maize by Jindal et al(2012). Nair et al(1995) reported significant positive and negative correlation of egg

laying byA. soccata in sorghum with maximum and minimum temperature, respectively. Its correlation

with morning and evening relative humidity was significantly negative and with sunshine hours was

significantly positive.

Effect of Nitrogen on incidence of Atherigonaspp.

The introduction of hybrids and high yielding varieties responsive to fertilizers has impact on

insect pest abundance also. Sharma and Singh (1975) reported that more application of nitrogenous

fertilizer in maize prompted growth and vigour of plants and helped in recovery of plants from shoot fly

damage. Nitrogen treated sorghum plants were more preferred by shoot fly for egg laying than control

plants but reduced incidence of shoot fly was observed with nitrogen application and it might be due to

vigorous fast growth of plants by nitrogen (Mote and Ramshe 1987). However, Chamarthi (2008)

reported that more vigorous plants were preferred by shoot fly for egg laying.

Biological control of A. naqvii

Three parasites namely, Tetrastichus nyemitawusRohwer, Tetrastichus spp. andNeochrysocharis

spp (Eulophidae) were reported parasitizing A. naqvii from Udaipur and Rajasthan (Kundu and Kishore

1972). Egg parasitoids i.e. Trichogramma spp. and Trichogrammatoidea spp. were reported from related

speciesA. soccata (Sharma 1985).

2.6. Other insect pests infesting spring maize

The availability of maize at one or more stages of growth throughout the year added new

dimensions to the pestilence front (Kumar and Kanta, 2011). Insects hitherto unknown to attack the maize

have become problems, as in present studies small brown planthopper Laodelphax striatellus (Falln) isbeing reported for the first time infesting spring sown maize in the Punjab. The brief description of insect

pests prevalent in spring season is as under:

Maize stem borer, Chilo partellus(Swinhoe) is a widely distributed insect pest in maize

and sorghum agro-ecosystem in India. The pest is active from March to October and has 6 7 over

lapping generations (Kumar et al 2005). The major loss was caused in the early stages of the plant. The


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freshly hatched tiny larvae began to feed on the tender leaves, particularly in the central whorl, which

later emerged out in a severely fenestrated condition. Thereafter, the larvae bored into stem to form

tunnel. In case of younger plants wherein sufficient stem formation had not taken place, the caterpillar

cut the growing point of the crop and the base of the central whorl got badly damaged, resulting in the

drying up of the central whorl and forming deadheart. This condition did not occur in the later stagewhen the stem was so thick that even a large number of larvae could continue to tunnel therein without

leading to any external symptom. Right from germination till harvest, maize crop suffered from

depredation of this borer. All parts of the maize plant except roots were attacked (Panwar 2005). In

peninsular India, the winter was not severe, therefore, the pest remains active around the year (Sharma et

al 2006). The management of this pest involve use of resistant cultivars, manipulation of sowing dates,

napier bajra hybrids as trap crop, intercropping of maize with pulses, ploughing up of field after the crop

harvest, optimum seed and fertilizer rate, use of egg parasitoid Trichogramma chilonis and spraying of

insecticides at early whorl stage of plant growth, spot application with granular insecticides (Hari and

Jindal 2009, Jalali and Singh 2003; Kumar and Kanta 2011; Sarup et al1978; Srinivas and Panwar 2003).

The extent of damage of this pest in spring sown maize is not reported in literature.

Army worm, Mythimna separata (Walker) is a polyphagous graminaceous pest.

Srivastava and Khan (1961) observed that the army worm cause heavy losses to maize at two stages of its

growth, viz., immediately after germination up to development of nodes and internodes; and secondly one

month after sowing. The late infestation results in complete defoliation due to larval feeding from edge

towards mid-rib. The pest attacks winter maize crop and incidence increases during March-April. The

larva also attack maize silk in April-May.

Corn earworm,Helicoverpa armigera(Hbner)is a polyphagous pest and noticed in summer and

winter season maize in Punjab. There may be as many as eight generations in a year. The young larvae

start damaging tassel and move downwards. Eat silk and may tunnel in the ears and damage grains, in the

milky stage. The damage in the ear may form a channel like structure, which is seen after exposure of the

grains. The attacked cobs show masses of moist excreta on them (Kumar and Kanta 2011). Other silk

cutter, Euproctis virguncula Walker feeds on the freshly matured silk during September-October, but do

not effect the pollination (Sandhu and Kaushal 1972, Sandhu et al1974b).

Cutworms, two species belonging toAgrotis,have been reported to attack maize. The caterpillars,

hiding during day time in cracks in soil, damage maize seedlings at dusk. The older larvae kill the plants

by cutting it just above the soil surface. At Pantnagar, the larvae number as high as 18 per meter length

were recorded infesting spring sown maize (Kumar and Kanta 2011). The climbing cutworm, Rhyacia
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herculea (Corti and Draudt) was reported to cause 20 to 40 per cent loss in winter sown maize crop in

Bihar (Verma et al1979).

Grasshoppers are sporadic pests on maize crop. In favourable season they may prove harmful

and leave nothing on plant except stem and mid-rib of leaves (Kumar and Kanta 2011). These are

polyphagous pests, both nymphs and adults, generally feed on grasses before attacking the crop. Regular

summer ploughing and destruction of bunds to expose insect eggs to bright sun is recommended along

with mechanical control of gregarious (newly hatched) nymphs. Sugarcane leaf hopper or Pyrilla,Pyrilla

perpusillaWalker was reported to cause heavy loss to maize crop during March-May (Kumar and Kanta

2011). It feeds on number of host plants including maize (Kumarasinghe and Wratten 1996). Both

nymphs and the adults suck the plant sap from underside of the leaves. The infested plants turn pale and

in severe attack may dry up completely and the black fungus develops on the leaves which hinders

photosynthesis and growth of the plants.

The maize jassid, Zygnidia manaliensis (Singh) is one of the major pests of spring sown maize in

the Punjab. The nymphs and adults of this pest suck sap from leaves and produce whitish stippling, giving

bad look to maize fodder and deteriorating its quality (Sajjan et al 1982). They further reported that

malathion and phosphamidon gave complete control of this after 4 days of application. Economic losses

of 32 per cent in fodder yield during spring season and 15 per cent loss in grain yield of winter crop in the

Punjab have been reported by Singh (1991). The Jassid infestation on spring sown maize fodder was

reported to be high by 3rd

week of May (36/150 leaves) which declined later (Sodhi and Sekhon 1997).

The cereal thrips, Anaphothrips sudanensisTrybom cause damage to maize seedlings in winter

and spring seasons (Sandhu et al 1974a). The infestation has been reported to range between 29 to 86 per

cent. Both adults and nymphs suck the sap from leaves, growing tips and gradually congregate within the

leaf sheath to form colonies. As thrips start feeding on the oozed out sap, small silvery specks appear on

the infested leaves, which enlarge to form brown patches. These patches increase in size spread all over

the leaf which ultimately dries up. Heavy infestation at the seedling stage may cause complete loss of the

crop. Its population reaches peak in February to April (Mathur 1988).

Small brown planthopper, Laodelphax striatellus is being reported for the first time infesting

spring sown maize in the Punjab in the present studies. L. striatellus commonly occurs in Taiwan, Japan,

korea, China and the palearctic regions. Shukla (1979) first reported its prevalance in India on rice

nursery (variety Jaya) in the farmers fields near Ludhiana, Punjab. Thus could be distinguished from

white backed plant hopper by coloured scutellum as against white. It is polyphagous and its hosts include

rice, maize, oats, tall oat grass , wheat , barley etc. It vectors a number of viral diseases like Barley

yellow striate mosaic virus (BYSMV),Maize rough dwarf virus (MRDC),Northern cereal mosaic virus
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(NCMV; including the Wheat rosette stunt virus - WRSV),Rice stripe tenuivirus (RSV), Rice black-

streaked dwarf virus (RBSDV) and Wheat chlorotic streak virus (WCSV) (Caciagli 1991).The life table

studies on five varieties of rice, wheat and two weed speceis i.e. Echinocloa crusgalli and Leptochloa

chinensisshowed that nymphal duration onE. crusgalli was shortest (23 days). E. crusgalli was the most

suitable host follwed by japonica rice variety and then wheat (Li et al2009). High temperature determines

the ups and downs of small brown planthopper population. The development duration, longevity of

adults, pre oviposition and oviposition duartion decreased with the increase of temperature from 18oC to

27oC, whereas development of nymph became slow at 30oC and the developmental duration was delayed

about 16 days. The survival rate was higher (81-88 %) at 21-27oC, but it decreased to 5 % as the

temperature increased to 30oC. At 30

oC the longevity of female adultswas very short and they did not lay

eggs (Zhang et al 2008). L. striatellus harbours intracellular yeast like symbiotes in the fat body,

transmitting them to next generation through the female ovary. High temperature of 35oCdestroyed the

yeast like symbiotes in the mycetocutes. Under the continuous high temperature no adults were obtained

(Noda and Saito 1979). The high temperature also influences the transovarial passage of rice stripe virus

(RSV) in small brown planthopper. Most of the females at 17.5oC showed high transovarial passage i.e.

82.6 % of viruliferous females passed RSV to progeny at the rate of more than 90%. The percentage of

females which showed high transovarial passage ( >90% ) was 60.9 % at 25oC and 12.5 % at 32.5

oC and

higher the rearing temperature, the lower was the percentage transovarial passage (Raga et al1998). The

fipronil, nitenpyram, chlorpyriphos are the few insecticides that provide effective control ofL. striatellus

in China and its populations have been discovered with resistance to organophosphate, carbamate and

neonicotinoid insecticide classes (Endo and Tsurumachi 2000, Gao et al 2008). The information of

infestation of this pest on maize is scanty.

To sum up this review, the available literature reveals that a number of maize genotypes/

varieties/ lines have been screened against Atherigona spp. in spring sown maize, but detailed

investigations regarding the bases of host plant resistance is required. A better understanding of the

behaviour of shoot fly and interaction of environmental factors could serve as a basis for manipulation of

the cultural practices, need based pesticide application to reduce the risk of high pest population build up

and to minimize its damage to the host plant. In the era of changing climate and introduction of new

intensive cropping pattern, the systematic information on insect pests incidence and extent of damage by

insect pests complex needs to be updated for strengthening the IPM programmes in different crops

including maize.
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Chapter-III

MATERIALS AND METHODS

The studies on the Incidence of insect pests and management of shoot fly, Atherigonaspp. in

spring sown maize were conducted at the Research Farm and the Maize Entomology Laboratory,Department of Plant Breeding and Genetics, Punjab Agricultural University (PAU), Ludhiana, during

spring 2011 and 2012. The university is situated at 30 45' N, 75 40' E with an altitude of 247 m.a.s.l.

One of the field experiments was also carried out at the farmers field in village Chagra of district

Hoshiarpur (Punjab). The biochemical analysis was carried out in the Quality Laboratory, Department of

Plant Breeding and Genetics, PAU, Ludhiana.

3.1. Procurement of seed of maize/ sorghum

The seed of different hybrids and inbred lines of maize was procured from Senior Maize Breeder,

Maize Section, Department of Plant Breeding and Genetics and Director Seeds, PAU, Ludhiana for

conducting the field experiments. The seed of sorghum variety SL 44 was procured from Incharge,

Fodder Section, Department of Plant Breeding and Genetics, PAU, Ludhiana. The seeds were stored air

tight at 40C in refrigerator for further use.

3.2. Test genotypes

The eight maizegenotypes viz., JH 3459, PMH 2, PMH 1, JH 3956, JH 31244, Parkash, LM 16

and CM 143 were tested in different experiments. These genotypes, recommended for cultivation in the

state by PAU, were selected on the basis of their field reaction to shoot fly as observed in the previousyears studies under All India Coordinated Research Project (AICRP) on maize.

3.3. Raising of the crop

The maize crop was sown under flat and raised as per PAU, recommendations (Anonymous

2010) except any insecticide application in the untreated control treatments meant for making

comparisons. The crop was sown @ two seeds per hill in each treatment plot of different experiments in

the field. After completion of crop germination, the thinning was done to ensure one plant per hill in each

treatment plot.

3.4. Population build up of insect pests

The experiment on population build up of insect pests in spring sown maize was conducted at the

farmers field in village Chagra of district Hoshiarpur under unprotected conditions. The maize cultivars

JH 3459 and PMH 2 with two nitrogen level of 90 and 120 kg N ha -1were flat sown in randomized block

design (R.B.D.) factorial with 4 replications on February 21 stduring 2011 and 2012. The nitrogen was


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applied in three splits as per PAU recommendations. Each treatment plot had 6 rows with 4 m row length.

The row to row and plant to plant spacing was 60 and 15 cm, respectively and the trial was managed as

per PAU recommendations (Anonymous 2010).

The observations on the number of eggs laid by Atherigona spp. on the plant and nearby soil

were recorded from 10 randomly selected plants in each plot at 7 ,14 and 21 days after germination

(DAG) during both the test years. The leaf injury and deadhearts incidence due to attack of shoot fly

were recorded from 7, 14, 21 and 28 days old seedlings from the inner 4 rows in each plot using standard

procedures (Panwar 2005). From this data, the per cent leaf injury and deadhearts incidence was

calculated separately as under:

Leaf injury incidence (%) = (number of plants with leaf injury symptoms/ total number of plants) 100

Deadhearts incidence (%) = (number of plants with deadheart symptoms/ total number of plants) 100

Similarly, the population counts of small brown planthopper, Laodelphax striatellus (Falln),

grasshopper nymphs; Sugarcane Pyrilla,Pyrilla perpusilla (Walker); coccinellids; and spiders were made

from 10 randomly selected plants per plot at weekly intervals starting from seedling emergence stage

onwards i.e. till the maturity of the crop. The damage by foliage feeder viz. maize stem borer, Chilo

partellus (Swinhoe); army worm, Mythimna separata (Walker); silk cutter, Helicoverpa armigera

(Hbner); and grasshopper spp. was recorded on the whole plot basis and was converted to per cent

incidence.

The two hybrids were compared for incidence and relative damage of insect pests under two

nitrogen levels. The grain yield was also recorded from four inner rows after adjusting at 15 per cent

moisture level and was converted to quintal per hectare.

3.5.Estimation of losses caused by insect pests in spring sown maize

The experiment on estimation of losses caused by insect pests in spring sown maize was

conducted at Research Farm, Department of Plant Breeding and Genetics, PAU, Ludhiana. The maize

cultivars JH 3459 and PMH 2 comparatively tolerant and susceptible to shoot fly, respectively (Jindal et

al2007) were sown in three sets based on sowing dates i.e. first sown on 29th and 27

thJanuary; second on

11th

and 14th

February; and third on 26th

and 28th

February during spring 2011 and 2012, respectively.Three treatments viz. complete crop protection from shoot fly and other insect pests; crop protection from

insect pests other than shoot fly and untreated control (no crop protection from any insect pest) were

given to each of the above two hybrids sown under each of three sowing date sets during both the test

years. The seed treatment with Gaucho (imidacloprid) 600 FS @ 6 ml/kg seed was done before sowing

for crop protection from shoot fly attack. The spot application of carbofuran 3 G in 2ndweek of April was
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given to the crop against C. partellus in 2012 only. The experiment was conducted in R.B.D. factorial

with 3 replications. Each treatment plot consisted of 5 rows with 3.6 m row length. The crop raising

practices except the application of insecticides in untreated control plots were carried as per PAU

recommendations (Anonymous 2010).

The observations on the number of eggs laid byAtherigona spp. on the plant and nearby soil were

made from 15 randomly selected plants in each treatment plot at 3, 7, 10 and 15 DAG in 2011 and at 7, 12

and 17 DAG in 2012 as no egg lying was observed at earlier observations. The leaf injury and deadhearts

incidence due to shoot fly were recorded from 10, 15 and 20 days old plants on whole plot basis using

standard procedures (Panwar 2005)to calculate per cent incidence. The population counts of small brown

planthopper,L. striatellus; grasshopper nymphs; Sugarcane pyrilla,P. perpusilla; coccinellids and spiders

from 10 randomly selected plants per plot were recorded at weekly intervals from seedling emergence

stage onwards i.e. upto maturity of the crop in different sets during both the test years. In 2011, the

population of L. striatellus was comparatively high and thus its population counts were recorded from

two sweep catches of insect collection net from each treatment plots. The damage by foliage feeders viz.

maize stem borer, C. partellus; army worm, M. separata; and grasshopper spp. was also recorded on

whole plot basis and was converted to per cent incidence.

The comparisons were made from the extent of losses caused by key insect pest i.e. shoot fly in

two hybrids sown during different periods to identify most damaging crop growth period, most

susceptible crop stage and to know whether early sown crop had any escape from this pest without any

adverse effect on its grain yield. Similar observations were made for other insect pests also. The

meteorological data was obtained from Department of Agricultural Meteorology, PAU, Ludhiana for

making the correlations between incidence and damage of insect pests with weather parameters i.e.

temperature, relative humidity, sunshine hours and evaporation prevailed during the period of studies. The

grain yield was recorded from inner three rows in each treatment plot, adjusted at 15 per cent moisture

level and was converted to quintal per hectare for estimation of comparative losses under protected and

un-protected conditions sown under three sowing dates.

3.6. Role of various morphological and biochemical plant characteristics in resistance against

shoot fly, Atherigonanaqvii

The experiments to study the bases of resistanceagainst most prevalent species of shoot fly in spring

sown maize in Punjab i.e. Atherigona naqvii in eight maize genotypes (JH 3459, PMH 2, PMH 1, JH

3956, JH 31244, Parkash, LM 16 and CM 143) were conducted during spring 2011 and 2012 at the

Research Farm, the Maize Entomology Laboratory and Quality Laboratory, Department of Plant Breeding

and Genetics, PAU, Ludhiana. The experiment to record incidence of shoot fly,A.naqviiand to study the
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morphological basis of resistance in maize genotypes against A. naqvii was conducted under field

conditions using fish-meal technique given by Nwanze (1997). The test genotypes were sown on 20thand

22nd

February in 2011 and 2012, respectively in R.B.D. with 3 replications. Each treatment plot had 5

rows with 3 m row length. The crop raising practices were followed as per PAU recommendations

(Anonymous 2010) except the application of insecticides. The optimum shoot fly population in field was

ensured by broadcasting the moistened fish-meal at the rate of 50 gm per m2

(Jindal et al 2007). The

correlation and regression coefficient for its infestation, biological attributes with morphological and

biochemical parameters were also worked out.

3.6.1. The following observations were recorded on various parameters:

3.6.1.1. Incidence of shoot fly: The number of eggs laid per plant was recorded from 15 plants per

treatment plot at 3 days interval from 3 to 15 DAG to assess antixenosis for oviposition in different

genotypes. The leaf injury and deadhearts incidence was recorded on whole plot basis at 5, 10, 15 and 20

DAG to work out per cent infestation. The proportion of deadhearts incidence out of total shoot fly

incidence (leaf injury and deadhearts) at 20 DAG was also worked out to calculate the recovery of

seedlings for assessing the tolerance in different genotypes.

3.6.1.2. Expression of antibiosis to shoot fly, A. naqvii : To study antibiosis test genotypes were

exposed to shoot flies adults under field conditions and were further used to study survival and

development of shoot fly on different genotypes. The field plants along with 75 plants of each genotype in

fish-meal baited small pots in 3 replications were sown and observed daily for egg laying and deadhearts

formation. The plants with eggs were tagged after ensuring that the laid eggs were of shootfly,A.naqvii

species only.To quantify antibiosis deadhearts formed in tagged plants in field and pots were labelled on

the day of their appearance to compute the larval period. Ten seedlings with deadhearts, six days after

deadhearts formation in each genotype were taken from each replication and placed in 50 ml vials. These

seedlings were dissected carefully to ensure the presence of the maggot; and on drying the seedling was

replaced with the fresh one of the same age.A similar separate set of vials was also maintained for each

genotype to ensure optimum number of pupae and adults for further studies. The observations were

recorded on life cycle parameters i.e. larval and pupal periods; larval and pupal survival; pupal weight and

fecundity (number of eggs laid per female) as per Dhillon et al(2005a). There were three replications foreach genotype and the experiment was carried out in completely randomized design (C.R.D).

Larval period and survival rate: The deadhearts with maggots (i.e. 6 days after deadheart formation)

placed in glass vials were observed daily for their pupation. The days from deadheart appearance to

pupation plus one day (because it takes one day for deadheart realization after egg hatching) was recorded

as larval duration (Meksongsee et al1981). The larval period was recorded separately for each larvae per


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replication; and the mean larval period and survival rate was calculated on the basis of surviving larvae

out of 10 larvae per replication.

Pupal period and survival rate: The time taken from pupation to adult emergence was recorded as

pupal period. The pupal period was recorded separately for each individual per replication and the mean

pupal period and survival rate was calculated from the pupae which emerged as adults. The additional

pupae of same age were obtained from the culture maintained in separate vials for each genotype. The

number of pupae survived or emerged as adults were recorded and expressed as percentage pupal

survival.

Pupal survival = (Number of adult emerged / Total number of pupae) x 100.

Pupal weight: Pupal weight (in mg) was recorded for individual pupa on an electronic balance, within 24

h of its pupation. The pupae were sorted into males and females; and their individual weights were

recorded separately in each replication comprising of three pupae of each sex. After weighing, the pupae

were placed in respective jars on moist sand to avoid their mortality because of desiccation for further

studies.

Fecundity: Three pairs of adults emerging from larvae reared on each genotype were released in each of

three replications i.e. in glass chimneys (19 cm height), each having its mouth covered with piece of white

muslin cloth and tied with rubber band. The bottom end of the glass chimneys were firmly adhered to the

soil inside the pots (12 cm dia.) to prevent any exit route left for the shoot flies to escape. The cotton swab

dipped in 20 per cent sucrose solution and brewers yeast + glucose in the ratio of 1:1 was kept in a Petri

dish under each chimney to provide food to the adult flies. Two one week old maize seedlings (planted in

pots of 12 cm dia.) of the same genotype, on which the larvae were fed, were provided to the shoot flies

as an oviposition substrate. The seedlings were changed with fresh ones after every 2 days and the data

on number of eggs laid in each case were recorded.

3.6.1.3. Evaluation of Morphologicalcharacteristics of maize genotypes:

The observations on various morphological characters were recorded at fifth leaf stage of

seedlings. The data on seedling vigour, leaf glossiness, trichomes, pigmentation, leaf length, leaf width,

leaf area and stem girth were recorded on the test genotypes grown under field conditions, while the dataon leaf surface wetness was recorded in seedlings grown under greenhouse conditions (Dhillon et al

2005a). There were three replications for each genotype.

Seedling vigour: The seedling vigour (in terms of plant height, leaf expansion, plant growth, robustness

and adaptation) was recorded on a 1 to 5 rating scale. The three observations were recorded for each


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genotype per replication. The ranking of genotypes was done as per following rating scale (Dhillon et al

2005a):

1 = highly vigorous (plants showing maximum height, more number of fully expanded leaves, good

adaptation and robust seedlings).

2 = vigorous (good plant height, good number of fully expanded leaves, and good adaptation and

seedling growth).

3 = moderately vigorous (moderate plant height with moderate number of fully expanded leaves and

fairly good seedling growth).

4 = less vigorous (less plant height with poor leaf expansion and poor adaptation).

5 = poor seedling vigour (plants showing poor growth and weak seedlings).

Leaf glossiness: Leaf glossiness (plants with pale green, shiny, narrow and erect leaves) was evaluated on

a 1 to 5 rating in the early morning hours when there was maximum reflection of light from the leaf

surfaces (Dhillon et al 2005a). The three observations were recorded for each genotype per replication.

The rating of genotypes was done as under:

1 = highly glossy (light green, shining, narrow and erect leaves).

2 = glossy (light green, less shining, narrow and erect leaves).

3 = moderate glossy (fair green, light shining, medium leaf width and less drooping leaves).

4 = moderate non-glossy (green, pseudo-shine, broad, and drooping leaves).

5 = non-glossy (dark green, dull, broad and drooping leaves).

Pigmentation: Pink pigment on leaf sheath was assessed on a 1 - 5 rating scale (Dhillon et al 2005a).

The three observations were recorded for each genotype per replication. The rating of genotypes was done

as under:

1 = leaf sheath with dark pink pigment.

2 = leaf sheath with fair pink pigment.

3 = leaf sheath with light pink pigment.

4 = leaf sheath with very light pink pigment.

5 = leaf sheath with green colour.

Leaf surface wetness: The test genotypes were planted in small pots (12 cm dia). The observations on

leaf surface wetness were recorded between 7.00 to 7:30 A.M. The seedlings at the 5th leaf stage were

brought to the laboratory; the central whorl leaf was opened and mounted on a slide with a sticky tape.

Water droplets on the leaf surface were observed under the microscope (10 x magnification). The three

observations were recorded for each genotype per replication. Leaf surface wetness was rated on a 1 to 5

scale i.e. 1 = leaf blade without water droplets, 2 = leaf blade with sparsely placed few water droplets, 3 =


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leaf blade near mid rib covered with water droplets, 4 = water droplets spread all over the leaf blade and

5= entire leaf blade densely covered with water droplets (Sharma et al1997).

Leaf length: The leaf length (cm) was recorded from fully formed 5th leaf (from the base) taken at

random in each genotype. The linear leaf length was recorded with measuring scale. The three

observations were recorded for each genotype per replication.

Leaf width:The leaf width (cm) was recorded from fully formed 5thleaf (from the base) taken at random

in each genotype. The width was recorded from upper, middle and lower portion of leaf with measuring

scale to calculate mean width. There were three observations for each genotype per replication.

Leaf area:For studying the leaf area (cm2) of different maize genotypes 5th

leaf (from the base) taken at

random was detached from the plant and the leaf area was determined using Cl-203 Laser Leaf Area

Meter (CID, Inc, USA). Three plants were selected from each genotype per replication.

Stem girth (Circumference):The stem girth (cm) was recorded from seedling at 5th

leaf stage. The mean

diameter (d) of the seedling was recorded from two sides using vernier caliper. The three observations

were recorded for each genotype per replication.

Stem girth: 2 (3.14) r or (3.14) d ; as d=2r

Trichomes: The presence and number of trichomes was observed on the abaxial surface central portion

of the 5th

leaf (from the base) taken at random. The following parameters were recorded:

Number of tr ichomes: The number of trichomes was determined per 200 m linear length using

Scanning Electron Microscope (SEM) as per standard protocol (Bozzola and Russell 1999). Imaging and

counting was performed from three regions of single leaf per genotype.Tr ichome length:The trichome length was determined from the same leaf region selected for counting

the trichomes of each genotype and was imaged using SEM as per standard protocol. Imaging and

measurement was performed from three regions of single leaf per genotype.

Tr ichome angle: The angle of trichome was also determined from the same leaf region selected for

recording the trichome number and length in each genotype and was imaged using Scanning Electron

Microscope (SEM) as per standard protocol. Imaging and measurement was performed from three regions

of single leaf per genotype.

Standard protocol for imaging leaf samples under SEMThe leaf hairiness parameters, viz. trichome number, trichome length and angle of insertion of

trichome were analyzed and imaged under Scanning Electron Microscope (SEM) at the Electron

Microscopy and Nanoscience (EMN) Laboratory, College of Agriculture, PAU, Ludhiana as per standard

protocol given by Bozzola and Russell (1999). Fresh leaves of each test genotype were collected and

immediately immersed in individual vials containing 2.5 per cent glutaraldehyde solution for primary


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fixation and kept overnight at a temperature of 4C. The leaf specimens were then washed thrice with

distilled water. For secondary fixation, the specimens were immersed in 4 per cent osmium tetraoxide

solution for a period of 2-4 hours at 4C. After post-fixation, the specimens were again washed thrice

(each washing of 5 to 10 minute duration) using distilled water.

Dehydration of the specimen discs was performed using different grades of ethanol (25, 50, 70,

95 and 100%) each for a period of 20 minutes whereas the final dehydration (with 100% ethanol) was

performed for 30 minutes. The specimens were dried to critical point in CO2 at 5oC and mounted on

aluminium stub using double-sided carbon tape. Each specimen leaf disc was mounted with its lower

surface up allowing the lower epidermal surface of each leaf to be examined. The mounted leaf specimens

were sputter-coated with a thin layer of gold using an automated sputter coater. Finally, the specimens

were examined and imaged using Hitachi S-3400N Scanning Electron Microscope operated at an

accelerating voltage of 15 KV using secondary electron detector.

3.6.1.3. Biochemical composition of maize seedlings in relation to infestation by shoot fly, A. naqvii:

For studying the biochemical basis of resistance, seedling samples representing 5thleaf stage were

used in each replication. A set of test genotypeswas grown in screen house to obtain shoot fly infestation

free plants for comparison of biochemical parameters (proteins, phenol, tannins, reducing sugars and free

amino acids) between healthy and infested plants. The 5th leaf stage maize seedlings, collected from the

field and screen house, were dried at 60oC in oven. The dried seedlings were cut and powdered in a

Willey mill using a 0.5 pore size blade??? to obtain a fine powder for estimating different

biochemical parameters. The leaf biochemical investigations were carried out in the Quality lab,

Department of Plant Breeding and Genetics, PAU, Ludhiana for the following parameters:

Estimation of total chlorophyll: Chlorophyll estimation from 5th leave of maize genotypes was

performed using hand-held SPAD-502 Plus Chlorophyll Content Meter (Konica Minolta sensing, inc.

Japan). The meter calculates a unit less Chlorophyll Content Index (CCI) value.

rough final

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