Effects of some insecticides on some biological parameters of cotton leafworm, spodoptera littoralis (lepidoptera : noctuidae)‎

Abstract EN

Toxicity and sublethal effects of fipronil, chlorantraniliprole, emamectin benzoate and novaluron against the 2^nd instar of Spodoptera littoralis larvae after 24 and 48 hrs were evaluated.

The LC₅ values after 48 hrs of exposure were 0.062, 0.0008, 0.0001 and 0.048 mg L^-1 for fipronil, chlorantraniliprole, emamectin benzoate and novaluron, respectively.

While LC₁₀ values after 48 hrs of exposure were 0.097, 0.0013, 0.0002 and 0.027 mg L^-1, respectively.

Treated 2^nd instar of S.

littoralis larvae by LC₅ and LC₁₀ values of fipronil, chlorantraniliprole, emamectin benzoate and novaluron showed significant (P < 0.05) reduction in larval body weights, larval duration, % pupation, pupal mean weight and % adult emergence rates.

However, the average time to the pupation (pupal duration) for larvae treated did not change significantly in all treatments compared to control.

Fecundity, fertility and adult longevity were strongly orsoftly reduced in all insecticide treatments compared to control.

These results suggest that sublethal concentrations of the tested insecticides may reduce the population growth of S.

littoralis by affecting the development and reproduction.