Impact of Neonicotinoid-Based Insecticide Treatments on Non-Target Arthropods in Cotton Cultivation

The use of neonicotinoids in cotton cultivation contributes to the control of pest organisms but may also affect beneficial arthropods involved in the natural regulation of pests. This study evaluated, under experimental station conditions (CNRA, Bouaké, 2024-2025 growing season), the impact of foliar treatments based on acetamiprid (three application rates), thiamethoxam, and a combination of emamectin-acetamiprid on non-target arthropods. The experiment was conducted using a randomized complete block design (six treatments) with five applications. Beneficial arthropods were sampled at 3, 7, and 13 days after application using the diagonal sampling method. A total of 202 individuals were recorded, dominated by black ants (Camponotus sp.) (60.4%) and lady beetles (Micraspis lineola and Exochomus nigromaculatus) (33.2%), along with red ants (Oecophylla sp.) and lynx spiders (Oxyopes spp.). Insecticide treatments generally reduced the abundance of beneficial arthropods, with reduction rates ranging from 27.8% to 61.1% for M. lineola and E. nigromaculatus, from 34.1% to 95% for Camponotus sp., and up to 100% for Oecophylla sp. These results highlight the importance of rational cotton protection strategies incorporating integrated pest management principles (intervention thresholds, selection of the least harmful treatments, and rotation of modes of action) in order to preserve biological control services. Within the conditions of this study, they indicate a potential risk of non-target impacts that should be validated across broader cotton-growing contexts.