In vivo Studies on the Effect of Warburgia ugandensis Crude Extracts Against Bacterial wilt in Tomato

Tomato plants are susceptible to Ralstonia solanacearum, a pathogen responsible for bacterial wilt, a severe soil-borne disease with no available cure. Warburgia ugandensis crude extract has shown biocontrol capabilities against pathogenic fungi and bacteria in animals, but data on its effectiveness in plants is limited. The current study was done to evaluate the in vivo efficacy of W. ugandensis crude extracts against R. solanacearum in tomato plants. W. ugandensis leaf and stem bark crude extracts were obtained using ethanol, methanol, hexane, and dichloromethane. The obtained crude extracts were tested against R. solanacearum in tomato at the greenhouse in triplicate. The data collected on bacterial wilt incidence, severity, stem diameter, height, and the number of branches and fruits set were analyzed using analysis of variance (ANOVA) at a 5% significance level. Tukey’s test was employed to determine significant differences between means at the same significance level. Tomato plants established in soil inoculated with R. solanacearum and treated with dichloromethane crude extract of W. ugandensis stem bark showed no sign of bacterial wilt disease and were comparable to the positive control. Tomato plants established in soil inoculated with R. solanacearum but treated with W. ugandensis leaf ethanol crude extract had the highest average height of 62.50 cm which was similar to positive control. Tomato plants grown in R. solanacearum-inoculated soils and treated with methanol crude extracts from W. ugandensis stem bark produced a significantly higher average number of fruits, 22.00, compared to those treated with crude extracts from other solvents. The study proposed that W. ugandensis crude extract has the ability to be used as antibacterial biocontrol against R. solanacearum. Further research is important to determine the bioactive compounds against R. solanacearum.