““TRICHODRMA AS A BIOCONTROL TRICHODRMA AS A BIOCONTROL AGENT AGENT ""

What is biological control, what are the benefits to its use

Need of biological control agents Mechanism of biological control agents Requirements of successful biocontrol

agents Working example of biocontrol

agentTrichoderma ssp. Available Biopesticides and its use in

Agriculture

Importance of plant diseases

Estimated annual crop production worldwide

Amount lost to disease, insects, weeds using current control measures

Additional losses without current control measures

$1.2 - 1.3 trillion$1.2 - 1.3 trillion

$500 billion$500 billion

$330 billion$330 billion

Verticillium wiltVerticillium wiltCitrus cankerCitrus canker

Fireblight of pearFireblight of pear Apple scab

Rice blast 

( IMF and CIA World Factbook, 2014)

2013: world spent $43.4 billion $43.4 billion on chemical pesticides

Of this, < 1%< 1% actually gets to where the pathogen is

What happens to the rest?

Ground water

Taken up by the plant

Development of resistance

Current approaches to disease control

Chemical

Identification of resistance genes

Introgressing into commercial cultivars

Problems with development of resistance, pyramiding genes

Breeding

Biological Control is an attractive alternative/supplement

Control of plant pathogens and diseases caused by them through antagonistic

microorganisms or botanicals is termed biological control agents

According to Baker and Cook’s (1974) - “Biological control is the

reduction of inoculum or disease producing activity of a pathogen

accomplished by or through one or more organisms other than man.”

Antagonistic microorganisms like species of Trichoderma, Penicillium,

Bacillus, Pseudomonas etc.

Chemical pesticides

Implicated in environmental and human health problems

– Require yearly treatments and expensive– Toxic to both beneficial and pathogenic

species

• Biological control agents– Non-toxic to human and animal– Not polluted – Host specific

•Only effect one or few species

WHEN : Biological control agents are

◦ Low cost◦ Labor intensive◦ Host specific

WHILE : Chemical pesticides are:

◦ cost-effective◦ easy to apply◦ Broad spectrum

How does Biological Control works

Nutrient Competition

Biological Control

Antibiosismycoparasitism

Induced resistance

Tolerance to stress through enhanced root and plant development

Inactivation of the pathogen’s enzymes

An ideal biocontrol agent should satisfy most all, of the following attributes

• Must not be pathogenic to plants and animals • Level of pathogen control must be high • Should live longer in soil or host tissues • Should have rapid reproductive capacity • Should be a good competitor • Should have high survival rate in soil or host

tissues • Should be capable of controlling more than

one pathogen • Should be suitable for long-term storage • Should be compatible to use with agro-

chemicals viz. fertilizers, pesticides etc.

1671 – First found in Germany

1794 – Identified by Persoon almost 218 years ago

1927 – Gilman and Abbott recognized four species based on colour, shape of conidia and colony appearance

>75 years ago the potential use of Trichoderma by Weindling (1932) and first to demonstrate the parasitic activity in wilt of Pigeon pea

Best known mycoparasite against many soil borne plant pathogens 

Very effective biological agent Free living Highly proliferating Non- pollutive Easily accessible Non phytotoxic Systemic ephemeral Readily biodegradable Cost effective Synergistic effect Longer shelf life Greater compatibility

A genus of fungi, including many species that can be used to control phytopathogenic fungi. generally, soil dwelling saprophytes. They have a rapid growth rate, sporulate abundantly, compete well with other show resistance to chemical pesticides and produce various

antibiotics (e.g., gliotoxin and viridin). control of wood-rotting, wound-infecting and soil-borne fungal pathogens of seedlings and mature plants.

Conidiophores

Conidia

Hyphae Morphological structure of Trichoderma

Kulkarni and Sagar (2007) mentioned the Trichoderma as asexual stage and Hypocrea as sexual stage

Position Asexual stage (conidia)

Sexual stage (ascospore)

Kingdom Fungi Fungi Phylum Ascomycota Ascomycota

Sub-division Deuteromycotina Ascomycotina Class Hyphomycetes Pyrenomycetes Order Monilliales Sphariales

Family Monilliaceae Hypocreaceae Genus Trichoderma Hypocrea

Cultures are fast growing at 25-30° C

Conidia forming within on week in

compact or loose tufts in shades of green

or yellow or less frequently white

Yellow pigment may be secreted into the

agar, specially on PDA

A characteristic sweet or ‘coconut’ odour

is produced by some species

Chlamydospores

Conidia

Phialides

Hyphae

Conidiophores

Septate hyaline hyphae.

Conidiophores arehyaline, branched

Phialides are hyaline,flask-shaped, and inflatedat the base.

The colour ofthe conidia is mostlygreen.

Trichoderma spp.may also producechlamydospores

Singh et al., 2007.

Potential bio control activities exhibited by Trichoderma

Kamala and Indira, 2012, Manipur

For space and nutrients under specific condition do not get substrate

Suppress growth of pathogen population

e.g: Soil treatment with Trichoderma harzianum spore suppressed infestation of Fusarium oxysporum f. sp. vasinfectum and F. oxysporum f. sp. melonis

(Perveen and Bokhari, 2012)

Mechanisms of action

Mycoparasitism

Antagonist fungi parasitize other pathogenic fungiHyphae of Trichoderma either grow along the host hyphae or coil around itE.g. : T. harzianum and T. hamatum were mycoparasite of both Scelerotium rolfsii and R. solani

Interaction – Coiling of hyphae around the pathogen, Vacuolization, Penetration by haustoria and lysis (Omero et al., 1999).

Recognize and attach to the pathogenic fungus and excrete extra-cellular lytic enzymes like β-1,3-glucanase, chitinase, proteases and lipase

(Schlick et al., 1994).

Trichoderma coils around, penetrates, and kills other fungi that are

pathogenic (i.e. cause disease) to crops. It can digest their cell walls

A clear view with an electron microscope

Trichoderma spp.(T) fungal strands coil (C) around the Rhizoctonia (R)

Initial stages of degradation (D) as a result of Trichoderma generated enzymes.

T: Trichoderma R: Rhizoctonia

Antibiosis It is the condition in which one or more metabolites excreted by an organism have harmful effect on one or more other organisms

In such antagonistic relationship spp. A produces a chemical substance that is harmful to Spp. B without a Spp. A deriving any direct benefit e.g: Trichoderma secreted - Trichodermin, viridine, Trichothecin, Sesqiterpine etc.

Growth inhibition of R. solani by the T. virens produced antibiotic gliotoxin . A: Gliotoxin amended B: non amended

Cont…

Trichoderma strains solubilize phosphates and micronutrients

The application of Trichoderma strains in rhizosphere of plants increases the number of deep roots, there by increasing the plants ability to resist drought

Plant growth promoter

Fig.: Enhanced root development from field grown bean plants as a consequence of root colonization by the rhizosphere competent strain T. harzianum

(Amin et al., 2010)

Cont…

Mass production of biocontrol agentsLiquid fermentation method

Substrates for mass multiplication: wheat bran, wheat straw, FYM, press mud, coir pith, ground nut shell, rice bran, etc

Carrier/ food base materials: Talc, vermiculite, molasses, gypsum, kaolin, peat, sodium alginate, Cacl2

Organism Trade Name

Target Crops

Trichoderma virens

SoilGard 12G3 Pythium, Rhizoctonia, and Root rots

Ornamental and food crop plants grown in greenhouses,

Trichoderma harzianum Rifai strain KRL-AG3

Plant Shield® HC

Fusarium, Pythium, and Rhizoctonia

Cucurbit vegetables, flowers, bedding plants,

Trichoderma harzianum Rifai strain KRL-AG2

T-22™ HC Fusarium, Pythium, and Rhizoctonia

Agronomic field and row crops, alfalfa, hay and forage crops, bulb crops, cucurbits, fruiting vegetables, herbs, spices, leafy vegetables, cole crops, legumes, root crops, small grains and tuber crops

Trichoderma harzianum Rifai strain KRL-AG2

T-22™ Planter Box

Fusarium, Pythium, and Rhizoctonia

Agronomic field and row crops, alfalfa, hay and forage crops, bulb crops, cucurbits, fruiting vegetables

There are several reputable companies that manufacture government registered products.

Trade Name Bio agent Manufacture

Eco fit T. viride Hoechst and Schering AgroEvo Ltd, Mumbai India

Super visit T. harzianum Fytovita, Czech Republic

Soil guard T. virens Certis Inc,Columbia,MD,USA

Root pro T. harzianum Efal Agri, Netanyl,Israel

Tusal T. Viride +T. harzianum

Tusal Carrera Ester, Lleida Spain

Agroderma, Bio-cure, Bioderma, Ecofit,

Rakshak, Trichosan

Trichoderma viride

Biocure (B&F) T. Viride and P. flourescens

1.Seed treatment•Dose: @5 g /kg of seed•Method: Make a paste or slurry adding 5 g in 10-20 ml of water . Pour 1kg of seed on to the paste or slurry and mixed properly to coat the seeds uniformly .Shade dry the coated seeds for 20-30 minutes before sowing

2.Tuber/Rhizome/Cutting treatment:•Dose: @ 10 g /litre of water•Method:Dip the tuber / rhizome/cuttings in the suspension prepare @ 10 g /litre of water. Shade dry for 15 minutes before planting

(Medhi,2009)

Seedling Treatment:•Dose: 300 g/ha.•Method: Prepare a suspension @ 5-10 g/litre of water. Dip the roots of seedling for 15minutes and shade dry for 15 minutes before transplanting

Nursery bed treatment:•Dose: 250 g for 400 sq.m nursery bed.•Method: 1) prepare a suspension by adding 250 g in 50 litres of water and drench the nursery bed soil. •2) Mixed 250 g in 2 kg cow dung / compost/FYM and spread over 400 sq.m. nursery bed and irrigate the bed.

Soil treatment:i) Direct broadcasting:•Dose: 300 g/ha.•Method: Mix 300 g in 6 kg of FYM. Broadcast in one ha of land and irrigate the field.

ii) Awaited broadcasting•Dose: 30 g/ha•Method: Mixed 30 g in 6 kg of FYM. Cover the mixture with polythene sheet for 7-15 days and broadcast in the field

iii) Furrow application:•Dose:300g /ha.•Method: It is highly effective in root crops like potato, ginger, turmeric etc and sugarcane.The mixture is applied in furrows at the time of earthing up or after 30 days of planting

• Decrease disease intensity.

• Reduce the use of chemical fungicides.

•Reduce undesirable effects from chemical pesticide.

• Play a key role in integrated management of diseases

•Safe for the users and the farming community.

• Provide natural long term immunity to crops and

soil

( Shrivastava , 1996 ).

•Deterious effects on non-target micro-organisms •Pathogens may develop resistance to the biocontrol agent •Pathogen replacement may follow control of target disease pathogen •Seasonal/weather phenomena can make biocontrol agent ineffective

( Shrivastava , 1996 ).

CONCLUSIONS

Biological control an attractive alternative to chemicalsTrichoderma species are effective in biological control of fungus-induced plant disease

Plant diseases cause major loss of food and money

Biological control occurs via several mechanisms

CompetitionAntagonismMycoparasitism