A TaqMan qPCR method for detecting kdr resistance in Aphis gossypii demonstrates improved sensitivity compared to conventional PCR–RFLP

Cotton aphid, Aphis gossypii Glover, has emerged as a prominent pest in Australian cotton produc- tion, and monitoring pesticide resistance including pyre- throids in field populations is crucial for its sustainable management. We examined the distribution of kdr resis- tance in 35 field-collected A. gossypii populations and used TaqMan qPCR assays with pooled samples. The study demonstrated proof of concept that pooled insect qPCR methodology provided effective detection with better sen- sitivity than individual PCR-RFLP genotyping techniques for the kdr resistance allele. The practical outcome is that routine resistance monitoring can examine more sites while increasing the likelihood of detecting incipient resistance at those sites. More importantly, the method is adaptable to any genetically caused resistance and so not limited to A. gossypii or even insect control. It cannot be overstressed that the ability to detected resistance at very low frequen- cies is critical to all sustainable resistance management. Early detection of resistance provides critical time for the modification of chemical use prior to potential insecticide control failure.