Evaluation of Toxicity of some Novel Molecules of Insecticides against Spodoptera litura (FAB.)

An attempt was made to assess the toxicity of some novel molecules of insecticides against Spodoptera litura (Fab.). The dose mortality response to the 7 d old larvae of S. litura indicated that spinosad at 24 h was 4.773 times more toxic than cartap hydrochloride at LC₅₀ value. By the lapse of time this ratio further increases to 82.5 at 48 h and 71 times at 72h. The relative toxicity ratio (RTR) of novel molecules at LC₅₀ value in comparison to cartap hydrochloride at 24h and 48h were: spinosad (4.77, 9.9)> fipronil (1.59, 3) and at 72h the values were spinosad (10.14) and fipronil (2.54). LC₅₀ values of cartap hydrochloride, fipronil, spinosad, as 0.44% and 0.126%; 0.0418% and 0.079%; 0.004% and 0.0264% respectively at 24 h.