Bioefficacy of some insecticides against hadda beetle, Henosepilachna vigintioctopunctata (Fabricius)

The contact toxicity of fenpropathrin, chlorfenapyr and spinetoram was determined against 8d, fenvalerate, thiamethoxam + lambda-cyhalothrin and cyantraniliprole against 10d and flubendiamide, chlorfluazuron and carbosulfan against full grown grubs of H. vigintioctopunctata by atomization method in three separate experiments. In the first experiment fenpropathrin (LC₅₀ = 0.0016 and 0.0007%) was 14.25 and 18.85 times more toxic than chlorfenapyr (LC₅₀ = 0.022 and 0.013%) at 24 and 48 HAE and 42.40 times more toxic than spinetoram at 72 HAE (LC₅₀ level). Fenpropathrin at 0.002% and 0.001% concentrations required 10.75 and 33.44 h to cause 50% mortality. Chlorfenapyr with LT₅₀ = 21.72 h was 3.32 times faster in action than spinetoram (LT₅₀ = 72.24 h). The LT₅₀ of spinetoram at 0.07 and 0.05% were 20.55 and 40.62 h, respectively. In the second experiment thiamethoxam + lambda-cyhalothrin was 3.15 (LC₅₀ = 0.0013%) and 2.75 (LC₅₀ = 0.0004%); and cyantraniliprole was 2.73 (LC₅₀ = 0.0015%) and 1.57 (LC₅₀ = 0.00007%) times more toxic than fenvalerate (LC₅₀ = 0.0041 and 0.0011%) at 24 and 48 HAE respectively. Thiamethoxam + lambda-cyhalothrin (LT₅₀ = 10.08 and 25.25 h) was 1.95 and 1.42 times faster acting than fenvalerate (LT₅₀ = 19.70 and 35.93 h) at 0.005% and 0.002%, respectively. The LT₅₀ of cyantraniliprole @ 0.001% was 22.75 h. In the third experiment carbosulfan with LC₅₀ value of 0.0004% was 6.5 times more toxic than chlorfluazuron (LC₅₀ = 0.0026%) at 24 HAE. At 48 HAE, carbosulfan (LC₅₀ = 0.0002%) was 9 times more toxic than flubendiamide (LC₅₀ = 0.0018). The LT₅₀ of flubendiamide and chlorfluazuron at 0.005 and 0.002% concentration was 22.68 and 42.08, and 14.84 and 26.00 and that of carbosulfan at 0.0005 and 0.0002% was 21.46 and 38.83 h, respectively.