Conservation biocontrol - using existing beneficials
Pest management
in cotton is increasingly making use of beneficial insects and research
is identifying critical habitats, resources needed to maintain them
and ways of encouraging their activity. Eggs, larvae and pupae of
Helicoverpa moths, the main insect pests of cotton, are all
attacked.
Groups of neighbouring
cotton farmers are working together to implement Integrated Pest
Management (IPM) practices and so reduce their use of broad-spectrum
pesticides. This will help conserve and encourage beneficial insects
and spiders.
Transgenic cotton
producing toxic proteins from the bacterium, Bacillus thuringiensis
(Bt) is now widely used to help control Helicoverpa, but
it is possible the moths could become resistant. Refuge crops (with
no Bt) are grown with the transgenic cotton to produce large numbers
of susceptible moths and so help to reduce the risk of resistance
developing. These crops, along with trap crops which are grown to
lure Helicoverpa away from cotton, could be useful sources
of beneficial insects.
Recent research
has demonstrated that parasitic wasps can cause significant mortality
to Helicoverpa, that their populations are high in early-
and mid-season legumes, and it may be possible to augment their
populations using the right type of on-farm crop diversity.
Supported
by: Australian Cotton Cooperative Research Centre,
Cotton Research and Development Corporation
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