Resistance Level and Enzymatic Detoxification Responses in Field Populations 𝐴𝑔𝑟𝑜𝑡𝑖𝑠 𝑖𝑝𝑠𝑖𝑙𝑜𝑛 (Hufnagel) to Commercial Insecticides

The black cutworm, Agrotis ipsilon is a highly destructive and invasive agricultural pest that has developed resistance to a variety of insecticide classes. In this study, the susceptibility of three field populations of A. ipsilon, collected in 2023 from three Egyptian Governorates (Sharqia, SHA; Kafr El-Shaikh, KAF; Damietta, DAM), to methomyl, profenophos, lambda-cyhalothrin, chlorantraniliprole, spinosad, indoxacarb, emamectin benzoate, and methoxyfenozide were monitored and compared. At the same time, the detoxification enzymes activity of A. ipsilon in tested populations was determined. The results showed that the susceptibility of the A. ipsilon population in DAM was significantly higher than that of populations from SHA and KAF. Among them, the A. ipsilon population in DAM had developed low levels of resistance to indoxacarb (RR = 19.80-fold), emamectin benzoate (RR = 16.78-fold), chlorantraniliprole (RR = 14.04-fold), and spinosad (RR = 12.75-fold), and had developed very low-level resistance to methoxyfenozide (RR = 10.01-fold). While the populations of A. ipsilon from SHA, KAF, and DAM had developed very high-level resistance to three insecticides (methomyl, profenophos, and lambda-cyhalothrin). Activity measurements of the main detoxification enzymes show that cytochrome P450 (P450), glutathione S-transferase (GST), and the general esterases (ESTs) of the SHA, KAF, and DAM populations of A. ipsilon were significantly higher than those of the susceptible strain (AG-Sus). The findings, along with other strategies, are expected to help with the resistance management of A. ipsilon in different habitats.