Browsing by Author "Mabagala, Robert B"

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Banana xanthomonas wilt: occurrence and means of transmission in Kagera, Mwanza and Mara regions of Tanzania
(2016-02) Hashim, Ibrahim; Mabagala, Robert B
Abstract: Banana Xanthomonas wilt (BXW) disease is a major constraint of banana production in the Lake zone (Kagera, Mwanza and Mara) regions of Tanzania where banana plays an important role as a staple food and cash crop. Infected plants die and fruits rendered inedible. To assess the current status of BXW disease field surveys were conducted from December, 2011 to January, 2012 in Kagera, Mwanza and Mara regions. Twenty eighty banana samples with BXW disease symptoms were randomly collected from a total of 147 surveyed fields. Farmers’ knowledge of BXW disease was assessed using a checklist, discussions and direct field observations. Isolation of bacteria was done on Yeast Peptone Glucose Agar and identification was done based on morphological, biochemical and pathogenicity test. Results indicated that the incidence of BXW disease was highest (56.7 %) at Ihangiro and the lowest (10 %) at Ruhija and Mulela, in Muleba District; Nakamwa and Busagami, in Ukerewe District. Such results implied that, BXW disease is still a constraint to banana production in the surveyed districts. The results also indicated that BXW pathogen transmission was through infected farming tools (65.4 %) in Muleba District and infected planting materials in Tarime (50.5 %) and Ukerewe (45.8 %) Districts implying that these were the major means by which BXW disease was spread in the study area. About 58.33 % and 41.67 % of the farmers in Ibare and Kishanda villages, respectively, in Muleba District associated pied crow (Corvus albus L.) with the transmission of BXW causing pathogen. Results based on morphological, biochemical and pathogenicity test indicated that, four out of 16 bacteria isolated from infected banana samples were Xanthomonas campestris pv. musacearum (Xcm). Further studies on the relationship between the pied crow and Xcm transmission in Kagera, Mara and Mwanza regions, are recommended.
Resistance of Xanthomonas campestris pv. vesicatoria isolates from Tanzania to copper and implications for bacterial spot management
(Academic Journals, 2014-03) Shenge, Kenneth C; Mabagala, Robert B; Mortensen, Carmen N; Wydra, Kerstin
Thirty isolates of Xanthomonas campestris pv. vesicatoria (Xcv) from Tanzania were evaluated for sensitivity to copper sulphate (CuSO 4 :5H 2 0) using dilution plate counts. Ninety-three percent (28/30) of the isolates produced countable colonies on nutrient glucose agar amended with 0.8 mM CuSO 4 . All the Xcv isolates (7/7) from Arusha (northern Tanzania) grew on the copper medium. Isolates of the pathogen from Iringa (southern Tanzania) produced variable results (15/21). However, neither of the two Xcv isolates from Morogoro (Eastern Tanzania) grew on the copper medium. These results indicate long-term exposure of Xcv isolates from Tanzania to selection pressure for copper tolerance.