Studies on Toxicity, Persistence and Bio-efficacy of some new Insecticides against Helicoverpa armigera (Hub.) in Tomato
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Date
2011
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MPUAT, Udaipur
Abstract
Investigations were carried out on “Studies on Toxicity, Persistence and Bio-efficacy of some new Insecticides against Helicoverpa armigera (Hub.) in Tomato” in the Department of Entomology, Rajasthan College of Agriculture, Udaipur kharif during 2008-09 and 2009-10. The lowest LC50 values recorded for flubendiamide 480 SC were 0.00610 and 0.006163 per cent during 2008-09 and 2009-10, respectively. It was 11.8573 and 11.6469 times relatively more toxic to the standard check endosulfan 35 EC during 2008-09 and 2009-10, respectively. Based on the LC50 and relative toxicity, the tested insecticides in a decreasing order of toxicity could be arranged as flubendiamide 480 SC > indoxacarb 14.5 SC > beta-cyfluthrin 2.5 SC > lambda-cyhalothrin 5 EC > endosulfan 35 EC during both the years.
Bio-efficacy of different insecticides against H. armigera showed all the treatments to be significantly superior over control. Three sprays of flubendiamide 480 SC at 150 ml/ha were significantly superior to all the treatments which caused highest reduction in the population of fruit borer larvae; exhibited minimum fruit damage; highest marketable fruit yield (270.65 and 272.21 q/ha) and highest B:C ratio ( 1:2.80 and 1:2.81) during both the years. Flubendiamide 480 SC at 125 ml/ha (253.03 and 255.64 q/ha,) and indoxacarb 14.5 SC at 500 ml/ha (251.49 and 250.82 q/ha) followed the above treatments. No significant difference was recorded in the population of natural enemies (coccinellids and chrysopids) among different treatments and control.
Persistent toxicity (PT) and lethal time (LT50) for flubendiamide 480 SC at 125 and 150 ml/ha were 531.66, 4.78 days; 553.04, 5.18 days and 537.77, 4.93 days; 565.27, 5.32 days, during 2008-09 and 2009-10, respectively. The initial deposit 0.220 mg/kg recorded for flubendiamide 480 SC at 150 ml/ha which dissipated below detectable level (0.01 mg/kg) within 7 days. The half life and waiting periods of flubendiamide 480 SC were 1.80 and 2 days, respectively. After 2 days the tomato fruits were safe for human consumption. Soil samples collected at harvest did not show the presence of residue of flubendiamide 480 SC at 150 ml/ha.
Description
Studies on Toxicity, Persistence and Bio-efficacy of some new Insecticides against Helicoverpa armigera (Hub.) in Tomato
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Citation
Kanwar and Ameta, 2011