Understanding and managing diamide insecticide resistance in lepidopteran pests: Insights into RyR mutations and metabolic mechanisms

Abstract

Diamide insecticides function as modulators of ryanodine receptors (RyR) in insects and are categorized under group 28 by the Insecticide Resistance Action Committee (IRAC). Since their introduction in 2007, insecticides such as chlorantraniliprole and flubendiamide have been widely used to manage a variety of pests, particularly within the order Lepidoptera, as well as species in Coleoptera, Hymenoptera, Diptera, Hemiptera, and Thysanoptera. However, prolonged and extensive use has led to the emergence of resistance, especially among lepidopteran pests. This resistance is primarily attributed to RyR gene mutations and the upregulation of the detoxifying system. The mode of inheritance and associated fitness costs vary depending on whether the resistance mechanism is target-site-based or metabolism-based. This review examines the molecular mechanisms underlying diamide resistance in lepidopteran pests, drawing from published literature and the author's research findings. Particular focus is given to well-characterized RyR mutations such as G4946E and I4790M, as well as detoxification enzymes like CYP9A40, which has recently been implicated in resistance among noctuid pests. Practical strategies for resistance management are also discussed.