Efficacy of Insecticides against Agrotis ipsilon (Hufnagel, 1766) and Spodoptera littoralis (Boisduval, 1833) with Residual and Health Risk Assessment of Thiamethoxam in Sweet Pepper.

The black cutworm (Agrotis ipsilon Hufnagel, 1766) and the cotton leafworm (Spodoptera littoralis Boisduval, 1833) are significant pests that attack pepper plants globally. This study evaluated the efficacy of five insecticides against these pests under laboratory and field conditions; in addition, it assessed thiamethoxam residues in pepper leaves and fruits, and conducted a dietary risk assessment. Thiamethoxam demonstrated superior efficacy in laboratory tests, with LC50 values of 0.77 ppm and 1.6 ppm against 2nd and 4th instar cotton leafworm larvae, and 0.8 ppm and 1.56 ppm against 2nd and 4th instar black cutworm larvae. Field trials showed thiamethoxam achieved high reductions of 98.2% and 94% against cotton leafworm and black cutworm, respectively. Thiamethoxam residues in pepper fruits were below the maximum residue limit (0.7 mg/kg) 5 days after application, with dissipation rates of 72.5% and 73.05% after the first and second sprays. Dietary risk assessment indicated negligible short-term risks, with acute hazard indices (AHI) of 0.035% and 0.036%, and hazard quotient (HQ) values below the acceptable daily intake (ADI). These findings confirm thiamethoxam high efficacy against both pests, with safe residues in pepper fruits posing no significant health risks, making it a valuable component of integrated pest management programs.