Integrated assessment of phytosanitary practices against Amrasca biguttula and their impact on cotton yield in northern Côte d’Ivoire

Cotton production in West Africa is severely constrained by sap-sucking insect pests, particularly the cotton jassid Amrasca biguttula, which can significantly reduce yield through physiological damage to plants. While insecticide-based control remains the dominant management strategy, its effectiveness under smallholder conditions remains variable and context-dependent. This study aimed to compare the effectiveness of farmer-managed phytosanitary practices with controlled experimental insecticide treatments in Northern Côte d’Ivoire. A mixed-method approach was used, combining a survey of 36 cotton farmers and a randomized complete block design experiment with three treatments (Company A program, Company B program, and untreated control). Results showed that insecticide treatments significantly reduced jassid populations, with Company A achieving the highest efficacy (≈ 55% reduction), followed by Company B (≈ 38%). Cotton yields under experimental conditions ranged from 0.82 ± 0.12 to 1.18 ± 0.14 t/ha, with significant differences among treatments (p = 0.012). A strong negative relationship was observed between pest density and yield (R² = 0.68; p < 0.001), confirming the major role of A. biguttula in yield loss. However, yield differences between treatments remain moderate, suggesting that cotton productivity is influenced by multiple interactors beyond insecticide use alone. These findings highlight the limitations of chemical-only strategies and emphasize the need for integrated pest management approaches combining agronomic practices, pest monitoring, and ecological regulation.