Comparative Toxicity and Residual Activity of Botanical and Synthetic Insecticides Against Multiple Life Stages of Aleurodicus dispersus (Hemiptera: Aleyrodidae).

Abstract

The spiraling whitefly, Aleurodicus dispersus Russell (Hemiptera: Aleyrodidae) is a highly polyphagous and invasive pest that poses serious challenges to crop protection, particularly in tropical and subtropical agroecosystems. Given the rising concern over pesticide resistance and environmental risks associated with conventional insecticides, this study was conducted under controlled laboratory conditions to compare the efficacy of selected botanicals, fish oil rosin soap (FORS), organic salt, and synthetic insecticides against multiple life stages of A. dispersus. Standardized bioassays-including direct spray, dry film (simulating residual contact toxicity), and ovicidal assays-were employed to evaluate stage-specific responses in nymphs, adults, and eggs. Azadirachtin 5.0% and Azadirachtin 0.15% achieved over 96% adult mortality in the dry film method, suggesting notable residual efficacy. Among synthetic insecticides, Acetamiprid 20% SP showed the highest ovicidal activity (70.2% by day 10) and the lowest LC₅₀ (184.80 ppm). Neem-based treatments like Azadirachtin 0.03% and NSKE 5% demonstrated slower but significant toxic effects (LC₅₀ range: 2834.21-9359.42 ppm). Probit analysis supported consistent dose-response relationships. Rather than suggesting immediate field adoption, the findings highlight promising candidates for further evaluation under semi-field and field conditions. This is one of the first comprehensive studies to simultaneously assess direct, residual, and ovicidal effects of both botanical and synthetic insecticides against A. dispersus, offering valuable insights for integrating fast-acting and environmentally safer options in whitefly management programs.