Efficacy and persistence of biorational pesticides against insect and mite pests of tomato under protected environment

Abstract

Studies on the efficacy and persistent toxicity of pesticides against insect and mite pests, dissipation of newlinespinosad and abamectin and their safety interval in tomato fruits, intrinsic toxicity of abamectin, acetamiprid, newlineazadirachtin, bifenthrin, buprofezin, hexythiazox, melia (SMHEO-4), mineral oil, propargite, spinosad and newlinespiromesifen to second instar nymphs and adults of Trialeurodes vaporariorum and protonymphs and adults newlineof Tetranychus ludeni were carried out under protected environment at Experimental Farm and Toxicology/ newlineBiopesticide Laboratory of Department of Entomology, CSKHPKV, Palampur, India studied at an elevation newlineof 1290.8 m. a.s.l. during 2010-11 and 2011-12. The lethal concentration computed against second instar newlinenymphs of T. vaporariorum revealed that the azadirachtin was found most toxic with LC50 and LC90values of newline0.00046 and 0.00331 per cent followed by abamectin (0.00051%; 0.00335%) and acetamiprid (0.00068%; newline0.00420%). However in adults of T. vaporarioum, abamectin with LC50 and LC90values of 0.00095% and newline0.00597 per cent was found most toxic followed by acetamiprid (0.00108; 0.00714%). The intrinsic toxicity newlinestudies of different pesticides against protonymphs and adults of T. ludeni revealed that abamectin was newlinehighly toxic with LC50 and LC90 values of 0.00021, 0.00133; 0.00043, 0.00287 per cent, respectively newlinefollowed by bifenthrin (0.00043%, 0.00363%; 0.00065%, 0.00446%). Population of T. vaporariorum (23.17), newlineT. ludeni (22.17) and Aculops lycopersici (1231.50) reached maximum in the mid of May-June under newlinenaturally ventilated polyhouse conditions, which had a positive correlation with the maximum temperature. newlineBioefficacy studies of insecticides/ biopesticides against immature stages and adults of T. vaporariorum newlineshowed that the abamectin (92.37%; 91.47%), acetamiprid (89.59%; 88.89%) and bifenthrin (77.62%; newline87.66%) resulted in maximum reduction of population and were statistically at par. Abamectin (94.67%) newlinefound most effective in reducing population of T. ludeni followed by propargite (