Spatio-Temporal Distribution of Fusarium Wilt and Floral Virescence, Two Major Diseases of Cotton in Côte D’ivoire: Agronomic Implications

Background : Vascular fusarium wilt and floral virescence are two major cotton diseases in Côte d’Ivoire, responsible for significant yield losses. Despite their impact, current knowledge about their distribution and dynamics remains limited, as most studies date back several decades. Given this situation, it is necessary to update the data in order to better understand the evolution of diseases in the main cotton-producing areas. The objective of this study is to analyze the spatial-temporal distribution of vascular fusarium wilt and floral virescence based on monitoring carried out on 600 smallholder plots between 2022 and 2024. Results : The results of the seasonal variation show that the incidence of fusarium wilt varies from one crop year to another, with no statistically significant difference between the three seasons ( p = 0.351 ). Spatially, the disease is mainly localized in the southern part of the cotton basin (below the 9th parallel), with three foci identified in the northern part. With regard to floral virescence, the seasonal dynamics exhibit a nearly similar pattern across the three cropping seasons, with varying levels of incidence. The 2022 cropping season exhibited the highest incidence rates. Unlike fusarium wilt, inter-season variations in floral virescence are statistically significant. The most affected areas are mainly located in the North of the cotton basin (above the 8th parallel). Conclusion : These results highlight the need to implement targeted phytosanitary strategies, including vector control and the introduction of resistant cotton varieties. They may also guide the choice of plots for seed production.