Abstract:
Black rot disease, caused by Xanthomonas campestris pv. campestris, is a major factor hindering
cabbage production in Kisii County. The objectives of this study were to; identify cabbage
varieties resistant to black rot disease, evaluate the effects of hot water seed treatment, mulching
and pruning on black rot disease for higher cabbage yields. The bacterium was isolated from
symptomatic leaves collected from ATC and KALRO farms in Kisii County. Isolation was done
in 0.85% sterile saline solution and the inoculum purified in YDC agar. Identification of the
bacterium was done using pathogenicity tests, cultural and staining characteristics. 50 grams of
Copenhagen and Gloria Hybrid seeds were inoculated using 104 CFU/ml of bacterial
suspensions. A portion of the inoculated seeds from each variety was treated with hot water at
50oC for 25 minutes. The remaining seeds were not treated to serve as control. All the seeds were
established in a greenhouse nursery beds and later transplanted into the field where the effects of
hot water seed treatment, mulching and pruning were evaluated on a scale of 1-9. Marketable
yields from each treatment were also recorded. Data was analyzed by Statistical analysis system
using Analysis of Variance. Mean scores were compared using mean separation procedures by
Least Significant Difference and the Tukey’s multiple range tests, with all tests of significance
being conducted at P≤0.05. The results showed significant difference between the two varieties
studied and among the four treatments. Copenhagen had disease mean score of 3.506 while
Gloria Hybrid scored 2.733. Hot water seed treatment, pruning, mulching and integration scored
2.398, 2.08, 1.625 and 1.352, respectively. The respective controls scored 5.136, 2.682, 2.659
and 5.659. Integration, Mulching, Pruning and hot water seed treatment had 76.1%, 71.3%,
63.3% and 57.6% effects on black rot disease, respectively. In summary, integration of hot water
treatment of seeds, mulching, pruning and the use of tolerant varieties gave better results. This
study recommends further research on other cabbage varieties not considered under this study
due to shortage of land, finances and time.
