Print This PageTechnology Overview
Bollgard II® technology offers growers a more cost effective and environmentally sustainable way to control Helicoverpa. However, it is important for cotton growers to continue to use an Integrated Pest Management (IPM) strategy. IPM has been used by the Australian cotton industry for many years to help control Helicoverpa. Bollgard II cotton is part of this insect control strategy - it is not the total answer to Helicoverpa pest control.
The genes in Bollgard II enable cotton to produce specific proteins (the same as produced by the bacterium Bacillus thuringiensis (Bt), a naturally occurring soil bacterium) which control certain Lepidopteran larvae when they feed on the vegetative and reproductive parts of the cotton plant.
It is important to understand that the various proteins produced by different strains of Bacillus thuringiensis (Bt) act on very narrow insect ranges and have no effect on any other living species – including other insects, birds, fish, animals or humans. Insecticides based on Bt have been used for decades for insect protection in dust or spray applications.
The specificity of control provided by the Bollgard II technology is due to a combination of:
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The target insects alkaline gut characteristics (ie high pH) which are necessary to transform the Bt protein into a toxic form. Most other living organisms have a more acidic (lower pH) gut.
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The unique receptor sites within the gut wall of the target insect, which accepts the specific Bt protein produced by the Bollgard II genes.
Bollgard II cotton plants continually produce Bt protein, in much the same way as the production of other proteins, within plants. As the target larvae develop on the cotton plant and begin to feed on the vegetative and reproductive plant material, the larvae ingest the Bt protein. The Bt protein then locks into a specific receptor site in the gut of the larvae which in turn causes a rupture (hole) to occur in the gut’s wall. This rupture disrupts the digestive process, causes the insect to stop eating, and leads to the death of the larvae.
Larvae need to feed on the plant to be affected by the Bt protein. The Bollgard II genes that produce the Bt proteins do not have any effect on the eggs of target insects.
