Using viruses and venoms to kill insect pests

All living things have to contend with viruses, bacteria and fungi that can cause illness or death. For example, humans get colds and ‘flu caused by types of viruses that grow in the cells of the nose and throat.

Baculoviruses, which specialise in infecting the caterpillars of many moth and butterfly species, can be used to control caterpillar pests. Scientists in the USA have genetically modified a virus that is intended to control cotton caterpillars. Scientists in Australia are considering importing these experimental baculoviruses for laboratory trials.

The GM baculoviruses contain a gene for a type of scorpion venom. When the baculovirus infects the caterpillar, it invades the caterpillar's cells. The cells take up the gene for scorpion venom and begin to produce it. The venom paralyses the caterpillar, in the same way that a scorpion sting would do. As a result, the caterpillar dies within 36 hours.

Before considering the release of these baculoviruses in Australia, scientists conducted a trial to see how the baculovirus behaved in Australian conditions - whether it infected non-target insects and competed with Australian baculoviruses.

Researcher Andy Richards (from CSIRO Entomology) concluded:

“The results show that the question of how a GM virus might interact with the cotton agro-ecosystem is more complicated than was originally thought. Further research is necessary before GM viruses can be widely used in this country and this work is important because it provides a focus for future investigations to better judge potential risks to the Australian environment.”