The efficiency of a semi-selective medium developed for Xanthomonas axonopidis pv. malvacearum (Xam), was verified with some modifications, in detecting the presence of X. axonopodis pv. phaseoli (Xap) in bean seed. Seed samples naturally infected with Xap were collected from the State of Paraná. The bacterial growth developed around the infected seed in the semi-selective medium after 12 days after incubation. The recovery frequency of bacterial colonies in relation to nutrient agar varied between 30 and 112%, depending upon the isolate. Efficiency of tolylfluanid to eradicate Xap from the bean seed was also verified in laboratory and glasshouse experiments. The bacteria was recovered from the untreated seeds, but not from the seeds treated in a solution of tolylfluanid (1.20g/L water), and placed in plates containing semi-selective medium. In the glasshouse, seeds treated with tolylfluanid, did not produce any symptoms of the disease till 30 days after seeding, whereas untreated seeds yielded 9,75% plants with typical disease symptoms. In an another experiment, untreated seeds yielded 7,08% and 11,67% diseased plants, whereas treated seeds yielded 0,5% and 2,4% diseased plants, 26 and 46 days after planting, respectively.
Common bacterial blight; Phaseolus vulgaris