Transcript Selection for host location and oviposition ability in

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
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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?
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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
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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
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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
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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
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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 25C, 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
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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 :
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Dispersal ability
Orientation mechanisms
Survival rates
Host plant location
Flight ability
Host acceptance
Oviposition success
Glasshouse selections
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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
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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