Epicuticular Wax Disruption as a Novel Mechanistic Strategy to Enhance Insecticidal Toxicity Against Aleurodicus dispersus on Eggplant and Cassava.

Abstract

The epicuticular wax layer in Aleurodicus dispersus (spiraling whitefly) serves as a hydrophobic barrier that limits insecticide penetration and contact toxicity. This study evaluated the potential of solvent, enzymatic, and natural agents to disrupt the wax layer and enhance insecticidal efficacy. Laboratory assays screened eight agents-chloroform, hexane, ethyl alcohol, xylene, salt solution, soap solution, lipase, and CTCRI cassava extract-across graded concentrations. Two-way ANOVA revealed significant main effects of solvent type (F₇,₇₀ = 10.697; p ≤ 0.01) and concentration (F_10,70 = 40.936; p ≤ 0.01) on percent wax removal. Lipase (0.5-2.5 g/L) and soap solution (1.5-10 g/L) exhibited the highest efficacy, confirmed through validation bioassays and Tukey's HSD grouping (p ≤ 0.01). Pot trials on eggplant (Solanum melongena) and cassava (Manihot esculenta) demonstrated that wax disruption substantially increased toxicological performance. Lipase and soap solution alone reduced whitefly density by 40%-55%, while combinations with botanicals (neem seed kernel extract [NSKE], azadirachtin) achieved 70%-90% mortality. Integration with triazophos or acephate resulted in near-total suppression (95%-100% mortality; ≤ 4 insects/leaf). Three-way ANOVA (p ≤ 0.01) confirmed significant treatment and interaction effects on both whitefly population and corrected mortality, indicating enhanced penetration and bioavailability of insecticides through wax dissolution. These results introduce epicuticular wax disruption as a mechanistic adjuvant approach in insect toxicology. Lipase and soap solution emerge as potent surface-active agents for improving insecticidal delivery and contact toxicity, offering a new direction in formulation science and integrated pest management.