This project revealed widespread resistance in GPA to three major insecticide groups that are commonly used to control aphids in Australia (synthetic pyrethroids, carbamates and organophosphates). The levels and distribution of resistance detected suggest resistance alleles are able to spread quite rapidly across large geographic distances. Additionally, low levels of resistance to neonicotinoids were detected in a small number of GPA populations from Queensland, South Australia and Western Australia. This is the first time neonicotinoid resistance has been detected in Australia. These novel findings have major implications for GPA management practices. Our industry survey report identified neonicotinoids as a high-use chemical group for GPA control in some regions of Australia, exposing an immediate need for new chemistries and resistance management strategies to help control this pest. We identified the presence of several resistant super-clones (biotypes) that dominate GPA populations across horticultural regions, improving our understanding of the clonal (genetic) make-up of GPA populations regionally and nationally. It appears that GPA is able to move freely between crops, between production areas and even across states. As well as determining the current levels of resistance in GPA, this project developed and optimised robust testing methodologies for newer chemistries available for GPA control (sulfoxaflor, pymetrozine, spirotetramat, cyantraniliprole). We then generated insecticide baseline sensitivity data to these ‘newer’ chemistries registered against GPA, allowing industry to monitor and respond quickly if there are any future changes in sensitivity of GPA to these products. As part of this project we conducted shadehouse and field trials that document the effectiveness of new chemistries compared with current industry standards, and produced data on several chemical products from new chemical groups that are effective in controlling GPA. Increasing the number of insecticide groups that are registered to control GPA in vegetable crops is essential to the ongoing management of resistance in this pest. Rotation of chemicals from different chemical groups is the cornerstone of any insecticide resistance management plan, and having a larger number of products to choose from should decrease the potential for resistance developing to any one product if they are used appropriately. The findings of this project, along with feedback from growers, advisors and agrichemical companies, have been incorporated into a regional resistance management strategy for GPA. Due to the wide range of vegetable crops grown across different regions nationally, along with a wide disparity in GPA