EFFECTS OF GARLIC AND GINGER ON THE SOFTROT DISEASE MANAGEMENT, GROWTH AND YIELD OF CABBAGE IN KISII COUNTY

Abstract: Soft rot disease in cabbage, primarily caused by bacterial pathogens, remains a major challenge to vegetable production globally. Conventional chemical treatments raise environmental and health concerns, necessitating the exploration of eco-friendly alternatives such as botanical extracts. This study aimed to evaluate the effectiveness of garlic (Allium sativum) and ginger (Zingiber officinale) extracts in managing soft rot incidence in cabbage under greenhouse conditions. The experimental setup involved multiple treatment concentrations (15%–50%) of garlic and ginger extracts, and their impact on soft rot disease incidence, severity, and cabbage plant health was assessed using survival analysis, ANOVA, and logistic regression techniques. Initial Chi-Square and ANOVA analyses showed statistically significant effects of garlic and ginger treatments on reducing soft rot incidence (Chi-Square = 96.6504, p < 0.0001; ANOVA F = 266.01, p < 0.0001). Treatments T1 and T4 exhibited the lowest incidence rates (mean = 0.15), while T6 showed the highest (mean = 0.2333), indicating variation in efficacy across treatments. Survival analysis using Log-Rank and Wilcoxon tests yielded mixed results. While general treatment application showed statistically significant differences (Log-Rank p = 0.0007; Wilcoxon p = 0.0016), survival tests across different treatment concentrations (15%–50%) were not significant (p > 0.05), suggesting that while garlic and ginger reduce soft rot overall, increasing concentration does not necessarily enhance efficacy. Logistic regression also confirmed the lack of significant differences among treatment concentrations in terms of failed plants and number of plants affected (p > 0.05). The model summary revealed a high R² value (0.9288), indicating that 92.88% of the variance in soft rot incidence was explained by garlic and ginger treatments, confirming strong model reliability and predictive power. Furthermore, leaf damage analysis showed the 20% treatment concentration as relatively effective (mean affected leaves = 1.29 ± 0.18), offering a promising middle ground for balancing efficacy and resource use. The study concluded that garlic and ginger extracts significantly reduce the incidence of soft rot in cabbage, validating their potential as sustainable plant disease management options. However, varying concentrations did not yield significantly different results, indicating that optimal application may be achieved at moderate levels such as 20%. These findings support the integration of botanical treatments into integrated pest management (IPM) strategies but also highlight the need for further field-level trials to validate efficacy under diverse environmental conditions.