Field Efficacy, Economic Performance and Extension Implications of Eight Insecticides for Dusky Cotton Bug Management in Multan, Pakistan

Abstract

Dusky cotton bug, Oxycarenus hyalinipennis, damages open cotton bolls and reduces lint and seed quali-ty. Locally relevant evidence is needed to support extension recommendations on effective and economi-cal insecticide options. Eight commercial insecticide treatments and an untreated control were evaluated during 2025 at the Cotton Research Institute, Multan, Pakistan, in a randomized complete block design with three replications. The first spray was applied on 15 August 2025. Population was recorded before treatment and on 18, 22 and 29 August, corresponding to 3, 7 and 14 days after treatment. A second spray was applied on 2 September; no post-second-spray population assessment was available. Seed-cotton yield was pooled across plot-wise pickings, and the economic comparison used the reported costs of the two-spray programme. Every insecticide reduced pest density relative to the untreated control. Spinetoram produced the greatest reductions at 3, 7 and 14 days (86.15%, 91.69% and 87.63%), followed by fipronil. Spinetoram and fipronil also produced the highest seed-cotton yields. Imidacloprid produced the highest reported gross-return-to-treatment-cost ratio, followed by cypermethrin plus chlorpyriphos. Weather associations from a separate 14-week unsprayed series were exploratory. Spinetoram and fipronil were the strongest biological options, whereas imidacloprid provided the most favourable re-ported economic return. Extension recommendations should distinguish biological efficacy from afforda-bility and should remain conditional on current product registration, label directions, local pest thresh-olds and validation across locations and seasons.