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Download Selection for host location and oviposition ability in Trichogramma
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Biological Control in Victorian Grape Vines using Trichogramma Dr. David Bennett Centre for Environmental Stress and Adaptation Research La Trobe University What is Trichogramma? A WASP Order : Hymenoptera Family : Trichogrammatidae Genus : Trichogramma Microscopic wasps 145 species worldwide Natural enemies of moths Egg parasitoids Trichogramma funiculatum What is Trichogramma? A WASP Order : Hymenoptera Family : Trichogrammatidae Genus : Trichogramma Microscopic wasps 145 species worldwide Natural enemies of moths Egg parasitoids T. funiculatum and T. carverae What is Trichogramma? A WASP Order : Hymenoptera Family : Trichogrammatidae Genus : Trichogramma Microscopic wasps 145 species worldwide Natural enemies of moths Egg parasitoids Trichogramma Life Cycle What are egg parasitoids? Different to regular parasites Trichogramma wasps lay their eggs into the eggs of moths Instead of a caterpillar emerging, a fully grown wasp climbs out Egg parasitoids are parasites that have a free-living adult stage Similar to the bad guys in the movie Aliens! T. brassicae on a Helicoverpa moth egg Trichogramma in Biological Control Currently the most widely used insect biological control agents in the world Natural enemies of over 200 pest moth species whose caterpillars attack agricultural crops Released on more than 8 million hectares Pests in Australia Examples of economically important pests include: – Helicoverpa (budworm) in processing tomatoes – Epiphyas postvittana (Lightbrown Apple Moth) in Chardonnay grapevines The latter damage grapes directly and spread Botrytis (bunch rot) Control is difficult with chemical sprays because this species is a leaf roller Chardonnay grapevines Lightbrown Apple Moth in grapes Pests in Australia Examples of economically important pests include: – Helicoverpa (budworm) in processing tomatoes – Epiphyas postvittana (Lightbrown Apple Moth) in Chardonnay grapevines The latter damage grapes directly and spread Botrytis (bunch rot) Control is difficult with chemical sprays because this species is a leaf roller Lightbrown Apple Moth Epiphyas postvittana Trichogramma in Australia Several endemic species attack pest moth species Natural Trichogramma parasitism rates are inadequate for control and too late in the season Trichogramma carverae is a species which can be bred in captivity on a grain moth host Breeding these wasps in huge numbers allows us to release them in grapevines where the pest has been found. Lightbrown Apple Moth cycle vs Trichogramma cycle LBAM eggs n um A ut er m Su m Sp ri ng Trichogramma Trichogramma in Australia Several endemic species attack pest moth species Natural Trichogramma parasitism rates are inadequate for control and too late in the season Trichogramma carverae is a species which can be bred in captivity on a grain moth host Breeding these wasps in huge numbers allows us to release them in grapevines where the pest has been found Wasp colony Trichogramma carverae reared on eggs of the grain moth Sitotroga cerealella Population founded from 18 wasps collected in Mildura Colony maintained in a controlled environment room at 25C, in constant light, at 60% humidity and provided with honey and fresh eggs every eleven days Trichogramma in Australia Several endemic species attack pest moth species Natural Trichogramma parasitism rates are inadequate for control and too late in the season Trichogramma carverae is a species which can be bred in captivity on a grain moth host Breeding these wasps in huge numbers allows us to release them in grapevines where the pest has been found Lightbrown apple moth cycle vs Trichogramma cycle LBAM eggs Trichogramma A ut um n Su m m er Sp ri ng • release timing is important Conclusions Releases early in the season increase parasitism and improve the level of biological control Can this bio-control agent replace chemical controls in Victorian grapevines? Can we produce Trichogramma strains that are more effective against these pests? Acknowledgements Horticultural Research Development Corporation Grape and Wine Research Development Corporation Australian Research Council Project aims Select for host location ability on potted grapevines under glasshouse conditions Fitness components selected for : – – – – – – – Dispersal ability Orientation mechanisms Survival rates Host plant location Flight ability Host acceptance Oviposition success Glasshouse selections 100 potted vines in full leaf Approximately 4,000 wasps released 120 LBAM egg cards exposed for 3 days Parasitised eggs collected to continue each line Assumption that each egg raft stung by one female, so that top 3% were selected 9 selections (3 populations x 3 selections) Further studies Monitoring egg presence for timing releases Release application rates Dispersal patterns and persistence Life history tradeoffs Impact of food Host deprivation Heritability of body size, wing shape Impact of fungicides Trichogramma carverae forewing structure R1 R4+5 MA Cu1 Cu2 1A 2A 3A
