DefinePK

Abstract

The Cola nitida tree represents a significant source of income for thousands of people. However, this crop is severely threatened by witches’ broom disease. The present study aimed to assess the phytosanitary condition of kola orchards by evaluating key epidemiological parameters across various localities. Specifically, correlations between the phenological stage of the orchards, relative humidity, and disease severity were investigated. In addition, the impact of disease severity on trunk and crown girth was analyzed. The highest prevalence (70.12%) and severity index (78.27%) were recorded in Aboisso. Overall, prevalence rates were relatively consistent across the surveyed localities. Pearson correlation analysis revealed no significant relationship between symptom prevalence and orchard relative humidity (r = 0.044, P = 0.893). However, a strong positive correlation was observed between symptom severity and relative humidity (r = 0.843, P < 0.001). A weak negative correlation was found between orchard age and disease severity (r = –0.280, P = 0.127). No significant correlation was detected between disease severity and kola tree trunk girth (r = 0.025, P = 0.66). Interestingly, trees exhibiting witches’ broom symptoms but lower severity indices had the largest crown sizes (r = –0.287, P < 0.001). Witches’ broom disease was found to be widespread in all surveyed areas, with consistently high severity indices. A comprehensive understanding of the epidemiology of witches’ broom disease is essential for the development of more targeted and effective management strategies.