Effects Of Hot Water Seed Treatment, Mulching And Pruning On Black Rot Disease Caused By Xanthomonas Campestris Pv. Campestris In Cabbage (Brassica Oleracea Var. Capitata) In Kisii County – Kenya

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.