Resistance Monitoring of Emamectin Benzoate 5SG in Cotton Bollworms in Tamil Nadu Karthik P.*, Kuttalam S., Gunasekaran K.1 Department of Agricultural Entomology, Tamil Nadu Agricultural University, Coimbatore, 641003, Tamil Nadu 1Department of Nanotechnology, Tamil Nadu Agricultural University, Coimbatore, 641003, Tamil Nadu *Email: karthikemamectin@gmail.com (corresponding author)
Online published on 31 August, 2017. Abstract The median lethal dose (LD50) of emamectin benzoate 5SG when monitored against cotton pink bollworm Pectinophora gossypiella, it was found to be 0.4282 mg larva−1 for F1 generation and 0.1802 mg larva−1 for F9 generation. The LD95 was found to decrease from 3.3760 (F1) to 1.1564 mg larva−1 (F9). The susceptibility index to emamectin benzoate based on LD50 and LD95 was 2.37 and 3.03, respectively. With regard to number of generations required for 10-fold decrease in LD50, it was found to be 27. Considering the F9 populations as the most susceptible, the tentative discriminating dose was fixed as 1.1mg−1. Assessing the level of insecticide resistance as one time survey in summer cotton revealed that the % resistance of H. armigera in five districts ranged from 3.33 to 10.00. The highest resistance (10%) was observed at Coimbatore district. The survivability of fruit and shoot borer Earias vitella varied from 6.66 to 15.00% against emamectin benzoate, with Erode population being highly susceptible. The % survival of pink bollworm varied from 3.33 to 6.66% at 1.1μg larva−1. Top Keywords Emamectin benzoate, Pectinophora gossypiella, Helicoverpa armigera, Earias vitella, resistance monitoring, LD50, LD95, discriminating dose, survival. Top |