Insect Resistance to Neonicotinoids - Current Status, Mechanism and Management Strategies

Pesticides are any substance used for controlling, preventing, destroying, repelling, or mitigating of pests. Neonicotinoids have been the most commonly used insecticide since the early 1990s, current market share of more than 25% of total global insecticide sales. Neonicotinoid insecticides are highly selective agonists of insect nicotinic acetylcholine receptors (nAChRs) that exhibit physicochemical properties, rendering them more useful over other classes of insecticides. This includes having a wide range of application techniques and efficacy in controlling sucking and biting insects. Although neonicotinoids are applied as foliar insecticides with possible direct exposure risks to honeybees, a large part of neonicotinoid use consists of seed coating or root drench application. There are three major detoxification enzymes involved in the development of resistance against insecticides viz., cytochrome P450 monooxygenases, carboxylesterases, and glutathione S-transferases. The repeatedly used use of compounds of the same active ingredients and application of excessive organophosphates (OPs) and pyrethroids in Bemisia tabaci. Resistance to insecticides resulting in loss of efficacy of many older insecticides has placed excessive pressure on novel products. One of the major limitations to resistance management is the occurrence of cross-resistance. This review briefly summarizes the current status of neonicotinoid resistance, the biochemical and mechanisms involved, and the implications for resistance management.