Insecticide Toxicology Laboratory Department of Entomology, College of Agriculture, Govind Ballabh Pant University of Agriculture and Technology, Pantnagar-263 145, Uttarakhand, India
*Corresponding author's E-mail: chandakanksha51@gmail.com
Online published on 6 April, 2018.
The persistent toxicity of 4 insecticides viz. ethion + cypermethrin, thiamethoxam + lambda-cyhalothrin, carbosulfan and chlorfenapyr was evaluated against 10d old larvae of S. obliqua (mean initial weight = 0.032 g/larva) on rajmah and mulberry plants separately. On rajmah plant, chlorfenapyr 0.02% was most persistent insecticide, with a PT value of 989.24 while carbosulfan 0.03% was least persistent with a PT value of 0.54. The data on residual toxicity of different insecticides in terms of mortality of test larvae showed that thiamethoxam + lambda-cyhalothrin (0.02%) and chlorfenapyr (0.02%) persisted for maximum period (>14 DAS) while carbosulfan (0.03%) persisted for minimum period (1 hr after spray). On mulberry plant also chlorfenapyr @ 0.02% was most persistent insecticide, with a PT value of 1047.6 and carbosulfan @ 0.03% was least persistent with a PT value of 1.11. The residual toxicity of thiamethoxam + lambda-cyhalothrin (0.02%) and chlorfenapyr (0.02%) persisted for maximum period (>12 DAS) while carbosulfan (0.03%) persisted for minimum period (1 hr after spray).
Persistent toxicity, Spilosoma obliqua, Morus alba, Phaseolus vulgaris, PT value
