Efficacy of certain insecticides against black cutworm Agrotis ipsilon (Lepidoptera: Noctuidae) in cotton field

Abstract

The insecticidal activity and biological effects of four compounds (Dolf-X, Indoprim, Kofrothrin, Terraguard) against the fourth instar larvae of the black cutworm, Agrotis ipsilon (Hufnagel) (Lepidoptera: Noctuidae), were examined by feeding and dipping techniques. In addition, its efficacy on cotton crops in open fields in two separate seasons (2023 and 2024). The results showed that all compounds exhibited good activity against larvae. Dolf-X has the lowest LC₅₀ value (highest potency) for both feeding and dipping methods. In addition, dipping generally displayed higher LC₅₀ values than feeding. The biological effects of all treatments prolonged larval duration, decreased pupation percentage, increased pupal malformation, and extended pupal duration compared to the control, where Terraguard showed the strongest effects on larval duration and pupation malformation (22.64 days and 59%, respectively) with the most significant impact on pupal weight and adult emergence (both normal and malformed). In the field evaluation, the data reported that all tested insecticides significantly reduced black cutworm larvae populations in cotton fields across two seasons (p < 0.05). Dolf-X and Terraguard consistently achieved the highest larval reduction percentages (90.44% and 98.83%, respectively), suggesting their potential as preferred choices for black cutworm control in these specific conditions. All four tested insecticides effectively controlled black cutworm larvae, but Dolf-X and Terraguard were the most potent.