Synergistic mosquito control via integration of spider peptide neurotoxin and Pyrethroid insecticide

Mosquitoes are important vectors of human diseases, with Anopheles sinensis posing substantial health risks across Asia. Although pyrethroids remain widely deployed, their effectiveness is compromised by resistance associated with sodium channel mutations. Spider peptide neurotoxins are potential biopesticides. Here, we evaluated the insecticidal efficacy of the Pardosa pseudoannulata neurotoxin PPTX-04, both alone and in combination with pyrethroids, against A. sinensis. Bioassays were conducted on laboratory and field populations, and functional analyses were performed on wild-type and mutant sodium channels (AsNav1-1). The co-toxicity of PPTX-04 with etofenprox was assessed across different mixture ratios. To enhance applicability, a nano-formulated version (Nano-PPTX-04) was developed and tested. PPTX-04 displayed potent activity against A. sinensis and retained efficacy against the L1014 sodium channel mutation that significantly reduced pyrethroid susceptibility. Mixtures of PPTX-04 and etofenprox produced synergistic toxicity at specific ratios (e.g., 3:1, 2:1). Notably, Nano-PPTX-04 exhibited superior potency relative to the native peptide, and its combinations with etofenprox yielded pronounced synergistic effects, particularly in pyrethroid-resistant field populations. Collectively, our laboratory-scale findings highlight the potential of PPTX-04, especially in nano-formulated form and in synergy with pyrethroids, as a potential strategy for mosquito control. This approach warrants further investigation as a viable solution to pyrethroid resistance.