Tracking in season dynamics of insecticide resistance in aphids Aphis gossypii (Glover) in different cotton growing ecosystems

摘要

Season-long monitoring of insecticide resistance in Aphids Aphis gossypii infesting cottons in three different agro-ecological conditions represented by Hanumanamatti, Dharwad and Annigeri in Karnataka was assessed through leaf dip bioassay. Among different insecticides a high degree of resistance was shown against neonicotinoids compared to organo phosphates. The order of resistance to each insecticide was Hanumanamatti > Dharwad > Annigeri. LC50 for imidacloprid was 0.18 and 0.15 ml/1 in Hanumanamatti and Dhawrad / Annigeri populations respectively. For thiamethoxam the LCsowas 0.17, 0.16 and 0.14 g/ml in for Hanumanamatti, Dhawrad / and Annigeri population. Irrespective of location and insecticides resistance increased from October onwards. The resistance was least to fipronil in all the three populations.