Susceptibility of armyworm Spodoptera litura (Lepidoptera: Noctuidae) to novel insecticides in Pakistan

The armyworm Spodoptera litura (Fabricius) (Lepidoptera: Noctuidae) is a serious pest of cotton (Gossypium hirsutum Linnaeus; Malvaceae), tobacco (Nicotiana tabacum Linnaeus; Solanaceae), and vegetables. Frequent application of various insecticides applied for its control has resulted in the development of a multiple resistance against commonly used insecticides. In the current study, field populations of S. litura were monitored in Pakistan for their susceptibility to diverse chemical classes, namely insect growth regulators (chlorfluazuron, lufenuron, flufenoxuron, triflumuron, methoxyfenozide), diamides (chlorantraniliprole, flubendiamide), spinosyns (spinosad, spinetoram), avermectins (abamectin, emamectin benzoate), indoxacarb, and thiocyclam by using a diet overlay bioassay during 2008-2013. Generally, no or a very low resistance was recorded to chlorfluazuron, lufenuron, triflumuron, methoxyfenozide, chlorantraniliprole, flubendiamide, spinosad, spinetoram, emamectin benzoate, indoxacarb, and thiocyclam. Resistance to flufenoxuron and abamectin was low to moderate in some populations of S. litura. The insecticides, showing no, very low, or low resistance can be used in rotation, along with other integrated pest management practices, to mitigate resistance to conventional as well as new chemistry insecticides in S. litura.