Current status of insecticide resistance in Aphis gossypii and Aphis spiraecola (Hemiptera: Aphididae) under central Indian conditions in citrus

Abstract

Abstract Most commonly followed practice to manage sucking insect pests during flushing season in citrus by citrus growers is foliar application of insecticides. Leaf dip bioassays for insecticides, viz., acephate 75 SP, dimethoate 30 EC, quinalphos 25 EC, chlorpyriphos 20 EC, spinosad 45 SC, imidacloprid 17.8 SL and thiamethoxam 25 WG, were conducted to assess the susceptibility of field collected Aphis gossypii and Aphis spiraecola (Hemiptera–Aphididae) adults. In general, the resistance ratio (RR) values indicated that the current levels in aphid population from major citrus belts of Maharashtra are in very low resistance category. Among seven insecticides tested on adult aphids collected from Nagpur, Amravati and Wardha districts during 2013–2015, neonicotinoid group proved the most effective in causing mortality as indicated by the lower LC50 values (0.01–0.04 ppm for imidacloprid; 0.03–0.05 ppm for thiamethoxam). Among the three locations, Amravati population has registered comparatively higher RR values indicating less susceptibility to insecticides. RR values calculated based on the base population indicated that the current resistance levels are between no and very low levels (1 < RR < 10).