Management of Whitefly (<i>Bemisia tabaci</i>) in Cotton (<i>Gossypium hirsutum</i> L.) through novel Insecticides

A field experiment was conducted to evaluate the efficacy of selected insecticides applied through trunk application against whitefly (Bemisia tabaci) on cotton. The treatments included pyrifluquinazon, clothianidin, thiamethoxam, flonicamid, diafenthiuron, pyriproxyfen, spirotetramat, and an untreated control. Observations on whitefly population were recorded at 3, 5, and 7 days after application. After the first application, pyrifluquinazon recorded the lowest whitefly population (3.65 whiteflies/leaf) at 3 days with the highest reduction (56.67%), followed by clothianidin (4.30 whiteflies/leaf; 51.57%) at 5 days, and thiamethoxam (5.13 whiteflies/leaf). At 5 days, maximum suppression was observed across treatments, with pyrifluquinazon achieving 65.47% reduction. However, efficacy declined slightly at 7 days, though pyrifluquinazon maintained the highest reduction (53.51%). Following the second application, pyrifluquinazon again showed superior control with 3.33, 2.87, and 4.20 whiteflies/leaf at 3, 5, and 7 DAA, respectively, achieving up to 66.20% reduction. Clothianidin ranked second with 53.84% reduction at 5 days. Similar trends were observed after the third application, where pyrifluquinazon recorded 5.13 whiteflies/leaf at 3 days and achieved maximum reductions of 63.94% at 5 days and 49.90% at 7 days. Spirotetramate consistently recorded comparatively higher populations and the least percentage reduction across all applications. Overall, population reduction increased from 3 to 5 days (63.20–66.20%) and declined slightly at 7 days (49.90–53.51%), indicating peak efficacy at 5 days after treatment. Pyrifluquinazon was the most effective treatment for suppressing whiteflies in cotton, followed by clothianidin and thiamethoxam. Spirotetramate showed the least effectiveness. The findings indicate that pyrifluquinazon treatments are effective for control of whiteflies under field conditions.