author(s)
Manjarika SB, K Sathish, AALH Baruah and Hazarika LK

abstract
Experiments were conducted in the laboratory to determine the LC₅₀ and relative toxicity of seven insecticides viz., clothianidin 100 g a.i./ha, bifenthrin 80 g a.i./ha, imidacloprid 20 g a.i./ha, spinosad 45 g a.i./ha, thiacloprid 100 g a.i./ha, flubendiamide 60 g a.i./ha, flonicamid 60 g a.i./ha and dimethoate 450 g a.i./ha along with control against cowpea aphid, Aphis craccivora Koch. Based on the LC₅₀ values, flubendiamide showed more toxicity at 0.027 ppm and 0.017 ppm after 24 and 48 hours, while spinosad was least toxic with 0.912 ppm and 0.246 ppm after 24 and 48 hours, respectively. The order of toxicity on the basis of relative toxicity was flubendiamide > clothianidin > thiacloprid > imidacloprid > flonicamid > bifentrin > spinosad, at 24 hours, while flubendiamide > thiacloprid > clothianidin > imidacloprid > bifenthrin > flonicamid > spinosad at 48 hours by taking dimethoate as unity.