When CESAR was established one major goal was to demonstrate that the genetics of D. melanogaster could be used to discover the targets of insecticides in pest species. Cyromazine resistance was adopted as the test system. We have now identified three different cyromazine resistance genes and are beginning to understand the mode of action of the chemical. One of these encodes a Multi Drug Resistance gene and provides evidence that efflux could be a significant insecticide resistance mechanism (John Damiano, Research Assistant). With support from an ARC-SPIRT Grant and Novartis Animal Health Australasia P/L the approach was expanded to include two other insecticides, nitenpyram and spinosad. Trent Perry (PhD student) has been able to rapidly identify the subunits of the nicotinic acetylcholine receptors targeted by these insecticides (ALS and SBD for nitenpyram and Da6 for spinosad). Given the importance to these insecticides this is a major discovery.

The ARC accepted our view that the Drosophila approaches had been validated and that research of this type should now been supported by industry related grants rather than via the ARC-SRC Core funding. Novartis Animal Health Australasia P/L have subsequently funded research on two new chemicals for which we will attempt to identify targets and Australian Wool Innovation has funded Trent Perry (Postdoctoral Fellow) to continue the work on nitenpyram and spinosad.

Within CESAR we are working to find novel insecticide targets using genomic approaches. Ariadne Tan Kristanto has been some fundamental research to investigate the potential to of lipases to be used as targets for the development of new insecticides that could be used to control H. armigera. A number of lipase genes, some of which are highly expressed in the larval midgut, have been discovered. Phylogenetic trees have been used to compare the gene products to other insect lipases. Moths have been reared on different lipid diets to assess the impact of diet on viability and developmental rate and the expression of the lipase genes.