The Australian cotton industry progressively embraced integrated pest management (IPM) to alleviate escalating insecticide resistance issues. A systems IPM approach was used with core principles that were built around pest ecology/biology and insecticide resistance management; together, these were integrated into a flexible, year-round approach that facilitated easy incorporation of new science, strategies, and pests. The approach emphasized both strategic and tactical elements to reduce pest abundance and rationalize decisions about pest control, with insecticides as a last resort. Industry involvement in developing the approach was vital to embedding IPM within the farming system. Adoption of IPM was facilitated by the introduction of Bt cotton, availability of selective insecticides, economic validation, and an industry-wide extension campaign. Surveys indicate IPM is now embedded in industry, confirming the effectiveness of an industry-led, backed-by-science approach. The amount of insecticide active ingredient applied per hectare against pests has also declined dramatically. Though challenges remain, pest management has transitioned from reactively attempting to eradicate pests from fields to proactively managing them year-round, considering the farm within the wider landscape.

Cotton or melon aphid, Aphis gossypii Glover, is an important pest of cotton, and recently the neonicotinoid group of insecticides has provided a key option for control where they are used as seed treatments and foliar sprays. Here we document for the first time in Australian cotton, resistance to three neonicotinoids (acetamiprid, clothianidin and thiamethoxam) in A. gossypii via diagnostic discriminating concentration assays that were also associated with field control failure. Subsequent full log dose probit analysis on strains with discriminating dose survivors confirmed acetamiprid, clothianidin and thiamethoxam resistance at 6.4-, 10-and 22-fold, respectively. Further laboratory pressuring of strains caused acetamiprid resistance to significantly increase to 22-fold but resistance factors to clothianidin and thiamethoxam were unchanged. Clearly there is a need to reduce overall neonicotinoid selection to prevent or slow any increase in neonicotinoid resistance. An effective method to contain resistance would be to move away from the more persistent neonicotinoid seed dressings to either organophosphate or carbamate-based products and to limit the use of neonicotinoid foliar sprays.

Insecticide resistance monitoring using a Potter precision spray tower with discriminating concentration and log dose probability techniques underpins the Australian insecticide management strategy for Frankliniella occidentalis Pergande. Abamectin, acephate, chlorpyrifos, dichlorvos, dimethoate, endosulfan, fipronil, malathion, methamidophos methidathion, methiocarb, methomyl, pyrazophos and spinosad are recommended for use against F. occidentalis but abamectin, methiocarb and pyrazophos are the only chemicals where insecticide resistance has not been detected. Although not registered, chlorfenapyr was effective against F. occidentalis and should be pursued for that purpose. In contrast, chlorpyrifos, dichlorvos and malathion resistance were detected at low to moderate levels throughout the study period putting their sustainable use for F. occidentalis control in doubt. Although it appears that acephate, dimethoate, endosulfan, fipronil, methamidophos, methidathion and spinosad remain effective, some populations contained a small percentage of thrips that survived exposure to a concentration that killed 100% of the susceptible strain. Subsequent laboratory selection of one such population separately with fipronil and spinosad caused an increase in resistance to these insecticides. These products must now be considered at risk. This is the first report of fipronil or spinosad resistance in populations of F. occidentalis.

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