Cotton virescence disease development has been studied according to genotypes mainly used by farmers, sowing dates and seed treatment in order to develop an integrated control strategy and thereby reduce cotton losses in the northern part of Côte d'Ivoire. Genotypes and sowing dates were carried on three improved cotton varieties sown at 6 dates. 27% of the farms received batches of seeds disinfected by Cotomence 45WP (Thiram + Imidacloprid). The 3 cotton genotypes expressed different levels of floral virescence disease attack. Variety Y301AR4 showed sensitivity to the disease with relatively high attack severities (18.44%). In contrast, cultivars Y301 AR3 and Y 331BR4 showed low attack severities of 3.45% and 8.20%, respectively. Disinfection of seeds before planting had no impact on the occurrence of cotton plant disease. Early sowing, carried out in June, has favored the development of the disease mainly due to the decrease of the rainfall regime and its poor distribution during the vegetative stage of the cotton plant. In contrast, subsequent sowing, those of July, would reduce the risk of attack by floral virescence. These results argue in favor of the genetic control of floral virescence disease and the shift of cotton cultivation calendar in Côte d’Ivoire.
