• The Plant Pathology Journal
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• v.26 no.2
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• pp.189-193
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• 2010

The in vitro antibacterial properties of two kinds of chitosan solutions and their effect in protection of broccoli from bacterial head rot disease were evaluated. Results showed that the two kinds of chitosan solution at different concentrations exhibited strong antibacterial activity against Pseudomonas fluorescens. However, the antibacterial activity of chitosan A solution increased with the increase of chitosan concentration up to 0.10 mg/ml while the antibacterial activity of chitosan B solution increased with the increase of chitosan concentration up to 0.05 mg/ml. In addition, the antibacterial activity of chitosan A and chitosan B solution of 0.10 mg/ml increased with the incubation time within 12 h and 24 h, respectively. The disease incidence and the lesion diameter of broccoli inoculated with P. fluorescens were significantly reduced when plants were either pretreated or post-treated with six different combinations of chitosan solutions. Overall, the results indicated that the two kinds of chitosan solutions had a potential in controlling bacterial head rot of broccoli.

• Korean journal of applied entomology
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• v.20 no.3 s.48
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• pp.135-145
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• 1981

Vegetables including Chinese cabbage and radish have been grown in alpine areas such as Muju, Namweon, Jinan and Jangsu during the shortage period of vegetables. The incidence of various diseases, environmental factors such as temperatures and rainfalls, and aphid populations as virus vector were observed at 10-day intervals from July to September in those areas. Disease incidence showed no significant difference among locations. Major diseases in Chin ese cabbage were bacterial soft rot, white spot, downy mildew, mosaic virus, Alternaria leaf spot and Fusarium seedling blight. Major diseases in radish were virus, white rust, black rot, root rot, leaf spot and Fusarium seedling blight. Disease incidence reached peak on Aug. 20 with $27\%$ infection in radish and with $20\%$ infection in Chinese cabbage during the growing season, and declined thereafter. Percentage of infection in each growth stage showed $25\%$ at root thickening stage and $26\%$ at the harvest time in radish; and the head formation stage, $24\%$ at the harvest time. The data indicate that disease incidence in radish increased rapidly at late growing stage and progressively increased in Chinese cabbage Seedling blight caused by Fusarium sp. and root rot caused by Aphanomyces sp. were also observed in those areas. Cool and wet weather appeared to be favorable for disease incidences during the rainy period of growing season although average temperature was about $25^{\circ}C$. Populations of aphids were lower in the alpine vegetable growing area than that of flat areas. Aphids as virus vectors from total aphids collected were $73.5\%$ or 289 virus vectors /993 total aphids in Namweon and $18.1\%$ or 31 virus vectors/171 total aphids in Muju. The most prerevalent species of aphids was Myzus persicae Sulz.