Ecotoxicological Risk and Differential Sensitivity of Natural Enemies to Pesticide‐Driven Threats in the Ndop Tropical Wetland Rice Agroecosystem, Cameroon: Implications for Integrated Pest Management

ABSTRACT Selecting low‐toxicity pesticides for Integrated Pest Management (IPM) is vital to protecting non‐target natural enemies and maintaining ecosystem health. This study assessed the ecotoxicological risk and natural enemies' differential sensitivity to pesticide‐driven biodiversity threats in tropical wetland rice fields in Ndop, Cameroon. The ecotoxicological risks associated with current farming schemes of 626 farmers were assessed using the Pesticides RIsks in the Tropics to Man, Environment and Trade (PRIMET) model based on farmers' pesticide application schemes, toxicity endpoints of the most sensitive parasitic wasp ( Aphidius rhopalosiphi ) and predatory mite ( Typhlodromus pyri ) species, and pesticide physicochemical properties. Wilcoxon signed‐rank test was used to compare pesticide application concentrations and risk profiles, and pairwise ratio analysis was used for differential sensitivity analysis. Pearson correlation established relationships between variables. Approximately 76.46% of the 17 pesticides (paraquat dichloride, 2,4‐D amine, glyphosate, carbendazim, chlorothalonil, copper (I) oxide, maneb, mancozeb, metalaxyl, potassium phosphonate, acetamiprid, chlorpyrifos, cypermethrin, emamectin benzoate, fipronil, imidacloprid, lambda‐cyhalothrin) used by farmers were overused, with the PRIMET model predicting definite or possible risks to both species for all seven insecticides, and lambda‐cyhalothrin (ETR = 98 800) and cypermethrin (ETR = 122 000) posing the highest acute and chronic definite risks. The fungicides carbendazim, metalaxyl, maneb, and chlorothalonil posed a possible risk (ETR ≤ 100) to T. pyri , while mancozeb posed a definite risk (ETR = 189.7) to A. rhopalosiphi . In contrast, chlorpyrifos (ETR = 6213) and fipronil (ETR = 4463) posed the highest definite risks to A. rhopalosiphi. Overall risk levels did not differ significantly between the two species ( p < 0.9), with T. pyri sensitive to 42.9% of applied pesticides and showing 284‐fold higher differential sensitivity than A. rhopalosiphi , mostly to pyrethroids. Pearson correlation revealed a highly significant positive relationship between lethal rates and applied concentrations ( r = 0.723, p < 0.001). Farmers in wetlands should replace high‐risk pesticides, especially pyrethroids, and adopt IPM to reduce risks to non‐target beneficial arthropods.