ISOLATION AND CHARACTERIZATION OF BACTERIA SOFT ROT PATHOGEN(S)

ABSTRACT

This research work was carried out to isolate and characterize bacterial soft rot pathogen of tomato (Lycopersicum esculentum). Standard microbiological methods were used to evaluate the microbial load present in the sample employing pour plate technique. Cultural and biochemical techniques were used to determine the identity of the isolates. Pathogenicity test was carried to evaluate out on the isolates to determine if disease condition can be induced on the tomato fruit. The disease severity index was evaluated to determine the virulence of the isolates. Data were analysed using statistical tools and results were documented. The results revealed that the total heterotrophic bacterial and fungal count of spoilt or diseased tomatoes samples obtained from Oba and Osa markets showed a general trend in the bacterial and fungal count of tomato samples. The counts ranged from 4.00 ±1.70 x 10⁴ cfu/g of sample in Osa market to 2.13 ±0.15 x 10⁴ cfu/g in Oba market. The fungal count was found to be in the range of 0.10 ±0.00 x10⁴ cfu/g for Osa market compared to 0.05 ±0.01 x 10⁴ cfu/g for Oba market. Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, Bacillus subtilis, Pseudomonas fluorescens and Bacillus cereus were the identified bacterial isolates. Only two of the six bacterial isolates were found to be pathogenic or induce disease condition in healthy tomato fruit. P. fluorescens was found to have45.79 % DSI compared to 18.37 % of B. subtilis. A decrease in the weight of the fruit usually accompanied by lesions or wounds on the skin of the tomato fruits is mainly responsible for the low market value of the produce. This is a nut shell affects the yield of the crop in storage, hence a form of yield loss.