Discovery of insecticide resistance in field‐collected populations of the aphid pest, Acyrthosiphon kondoi Shinji

Abstract

BACKGROUNDThe bluegreen aphid (Acyrthosiphon kondoi) is a worldwide pest of alfalfa, pulses, and other legume crops. A long overreliance on insecticides to control A. kondoi has potentially placed populations under selection pressure favouring resistant phenotypes, but to date, there have been no documented cases of insecticide resistance. Recently, Australian growers began reporting conventional insecticides failing to adequately control A. kondoi populations, prompting this laboratory‐based investigation into whether these populations have evolved resistance.RESULTSWe discovered four A. kondoi populations with moderate resistance (10‐40‐fold) to three different insecticide groups: organophosphates, carbamates and pyrethroids. However, A. kondoi populations showed no resistance to the butenolide, flupyradifurone. We were unable to identify general metabolic mechanisms using synergist assays (P450s, GSTs, or esterases), indicating the need for further detailed molecular investigations to characterise the putative resistance mechanism.CONCLUSIONInsecticide‐resistant A. kondoi present an emerging challenge to Australian agriculture. Growers require new tools and updated strategies, including access to newer chemistries, to alleviate their reliance on the few insecticides currently registered against A. kondoi. The implications of insecticide resistant A. kondoi for future management, the potential mechanisms of resistance, and future research priorities are discussed.This article is protected by copyright. All rights reserved.