Bio-Efficacy and Repellent Characteristics of Neem Seed Extracts against Common Aphids Infestations across Northern Punjab’s Arid Zones

Aphid infestations particularly Aphis gossypii, Rhopalosiphum maidis, and Myzus persicae pose escalating threats to smallholder cotton, okra, and sorghum production across northern Punjab’s arid agroecosystems, where erratic monsoons, rising temperatures (>42°C in summer), and declining soil organic matter undermine conventional insecticide efficacy and accelerate resistance development. This study evaluated the integrated bio-efficacy and behavioral repellency of cold ethanolic neem (Azadirachta indica) seed extract against these aphids under controlled laboratory, semi field cage, and participatory on farm conditions across Bhakkar, Layyah, and Mianwali districts (mean annual rainfall 250-310 mm). Standardized extracts (4.72 ± 0.31 mg g⁻¹) demonstrated concentration dependent lethality (LC₅₀ = 4.28% w/v at 72 h) and rapid antifeedant action (repellency index >0.75 at ≥5% w/v within 4 h). Semi field trials confirmed field relevance 10% extract reduced aphid density by 68.3% at 7 days after application statistically equivalent to imidacloprid (71.1%), with superior residual suppression at 21 days (-59% vs. baseline). On farm validation across 45 smallholder farms revealed 64.2% mean population reduction at 14 days, alongside high farmer acceptability (82%) due to absence of phytotoxicity, ease of preparation, and compatibility with existing spray equipment. Mechanistic analysis attributes sustained efficacy to multimodal action neuroinhibitory (azadirachtin), growth disruptive, and volatile mediated deterrence enhanced under low humidity conditions that improve cuticular penetration. Crucially, field performance was modulated by soil pH (7.8-8.3), which likely slowed azadirachtin hydrolysis. While rainfastness remains moderate (-30% efficacy post 10 mm rainfall), integration with Beauveria bassiana or natural enemy conservation positions neem not as a synthetic replacement, but as an ecologically anchored foundation for climate resilient IPM in Pakistan’s water stressed zones. These findings provide actionable, evidence based guidance for scaling botanical interventions within national extension frameworks.