NEW! Environmentally friendly insecticides.
Controlling insect pests safely is an important challenge for the 21st century. Over the past 40 years the total area of land under crops has changed little, yet output has trebled. Much of this has been accomplished by the use of chemical pesticides, which can affect a broad range of species and often have complications with residual toxicity.
Now a key to a safer insecticide has been found. An insect's hard exoskeleton or cuticle cannot expand as it grows, which means that it must be shed at certain moulting stages during the insect's normal life cycle. This process is controlled by ecdysone, an insect hormone that regulates gene activity during metamorphosis (development), reproduction and moulting.
CSIRO scientists have recently defined the structure of ecdysone receptors for certain insect pests. They are now using that information to design synthetic molecules to interact with these receptors to switch on the genes controlling growth and development at the wrong time, causing the insects to moult prematurely and die.
By targeting the ecdysone receptor of a specific insect, scientists will design insecticides that will bind selectively to that receptor. As the receptor is absent in humans, mammals, birds and fish, toxicity will be focused on the targeted pest species allowing preservation of biodiversity.
The new insecticide will help to overcome resistance problems, as the target site is fundamental to the insect's life cycle. It is also more efficient and therefore will require lower application doses.
While the technology can be applied to all insect pests, the first application of this research is directed to environmentally friendly and safe control of sheep blowfly and body louse.
Dr Tim O'Meara, CSIRO Molecular and Health Technologies, Timothy.O'Meara@csiro.au