biocontrol agents

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Characters of desirable bio control agents Presented by K.Ragunath


WHAT ARE BIO CONTROL AGENTS ? A system of controlling plant pests, nematodes and diseases without the use of chemicals, by employing predators, microbes, parasites that feed upon them.

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A M fungi Trichoderma spp Pseudomonas spp Azetobacter spp Bio control agents l k j m

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A M fungi Pseudomonas spp Bacillus spp Trichoderma spp Pasteuria penetrans Azetobacter spp B C A for nematode Control l j m k h f

FUNGI -Trichoderma spp : 

FUNGI -Trichoderma spp The fungal genus Trichoderma contains species that have the potential to be of economic importance Species in this genus are useful in the biological control of soilborne diseases (19) and tree decays. Some species produce useful bio chemicals and antibiotics and others are involved in plant disease .

Evaluation of Trichoderma spp as biocontrol against nematode : 

Evaluation of Trichoderma spp as biocontrol against nematode The implementation of Trichoderma in IPM can be achieved using a soil treatment which reduced amounts of fungicides Trichoderma harzianum & T. lignorum isolates were tested for their nematicidal activity against the root-knot nematode Meloidogyne javanica It is suggested that the main antinematode activity caused by T. harzianum takes place in the soil and not within the roots.

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Mycoparasitism Lytic enzyme chitinase Induced systemic resistance Antibiosis Trichodermin , dermadin, trichoviidin Competition Solubilization & sequestration of inorganic plant nutrients Mechanism of action k l m j f

Antagonistic fungus : 

Antagonistic fungus Many species of Trichoderma viridae Trichoderma harzianum Trichoderma koningi Trichoderma longibrachiatum Trichoderma hamatum

Commercial form : 

Commercial form

Bacteria –Pseudomonas fluorescens : 

Bacteria –Pseudomonas fluorescens Members of the genus display the following defining characteristics: - Rod shaped - Gram-negative - One or more polar flagella, providing motility - Aerobic, although some species have been found-to be facultative anaerobes (e.g. P. aeruginosa) - Non–spore forming - Positive catalase test


BIO FILM FORMATION Slime production also contributes to surface-colonising biofilms which are difficult to remove from food preparation surfaces


MECHANISM OF ACTION Antibiotic-mediated suppression -phenazines, tropolone, pyrrolnitrin Siderophore – mediated supression -produce fluorescent siderophores which link with supression ability Induced systemic resistance -activates multiple defence mechanism

Some keys : 

Some keys APPLICATION: - Soil-borne pathogens are controlled with the use of seed treatments or hopper-box applications and foliar pathogens by spray applications PRODUCT SPECIFICATIONS: Storage conditions: - Store in a cool, dry place in a sealed container ENVIRONMENTAL IMPACT AND NON-TARGET TOXICITY: - P. fluorescens. occurs widely in nature and is not expected to have any adverse effects on non-target organisms.

P. fluorescence : 

P. fluorescence

Pasteuria penetrans : 

Pasteuria penetrans Very effective against root knot nematodes in many crops. The lifecycle has four stages -spore formation -vegetative growth -fragmentation -sporogenesis

characters : 

characters Pasteuria penetrans and related forms are considered as potential biological control agents of phytoparasitic nematodes. Host adhesion is one of the most critical steps in the life-cycle of Pasteuria. The endospores are released in soil by decaying hosts The endospore represents the parasite durable stage as well as the infective propagule responsible for transmission.

Endospore formation : 

Endospore formation Pasteuria endospore from Helicotylenchus lobus Pasteuria endospores adhering to the cuticle of Hoplolaimus galeatus

AM Arbuscular Mycorrhizae : 

AM Arbuscular Mycorrhizae A symbiotic relationship with legumious plants. The VAM fungi penetrate the living cells of plants without harming them, and form the typical organs, such as vesicles and arbuscles, in the root . VAM fungi-infected plants have high potential of resistance to soil environmental stresses.


ROLE The known functions of VAM fungi on plants are that 1) the absorption of minerals, especially P, is promoted, 2) growth is stimulated, 3) high quality of fruits is produced every year, 4) resistance to environmental stresses is enhanced, and 5) resistance to soil disease is enhanced


CONSIDERATIONS While using care for Cut down the amount of agrochemicals and chemical fertilizers applied. Use fermented organic matter. Use soil conditioners, such as charcoal and zeolite. Consider the effectiveness of grasses . Improve soil pH and aeration.

Commercial form : 

Commercial form

VAM fungi : 

VAM fungi

Characters of desirable bio control agents : 

Characters of desirable bio control agents An desirable bio control agents should have following characteristics It should not be pathogenic to plants, animals, human beings and microorganisms. It should have broad spectrum of activity in controlling many types of diseases and must be genetically stable. It should have fast growth and sporulation It must be cultured under artificial media

Contd ………. : 

Contd ………. The innoculam must be capable of abundant production using conventional methods such as liquid fermentation and withstanding term storage until application It should be amenable for inexpensive mass multiplication and economically viable. It should have long shelf life It must be efficacious under different environmental conditions. It should be compatable with bio fertilizers

Contd…. : 

Contd…. It have host susceptibility to the action by the seed treating chemicals It should not be toxic to beneficial organisms in or on the target area. It should be easily formulated and method of application must be convenient and compatible with common cultural practices.

Contd… : 

Contd… It should easily establish in the soil with high persistence and survival capacity It should be biologically competitive with microorganisms


REFERENCE htm Biological control of crop diseases - D. Dinakaran, G.Arjunan, G.Karthikeyan. -

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