• The Korean Journal of Pesticide Science
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• v.7 no.1
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• pp.32-37
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• 2003

Bacterial soft rot by Erwinia carotovora subsp. carotovora is one of the diseases causing the biggest problem in Chinese cabbage. Chemical screening was conducted to select effective agents for controlling bacterial soft rot. Control effect of antibiotics, plant activator, and Biokeeper (avirulent Erwinia) to soft rot were tested by in vitro assay, nursery test, and field experiment. The in vitro assay was done by paper disc method and potato slice method. The nursery test was performed by using mineral oil inoculation method with consistent disease induction. The in vitro assay showed that streptomycin, oxolinic acid, bronopol, and copper hydroxide significantly suppressed the growth of pathogenic bacterium and the decomposition of potato slice. However, plant activators including acibenzolar-S-methyl did not show the suppressive effect on the growth of pathogenic bacterium and the decomposition of potato slice. When applied by the nursery test condition using mineral oil inoculation method with Chinese cabbage 'Kangruckyeurum', Biokeeper, oxolinic acid, antibiotics streptomycin, validamycin, and copper compound provided 83.5%, 95.2%, 91.2%, 57.5% and 79.9% in control efficacy, respectively. However, the control effect of acibenzolar-S-methyl showed to be low to cause phytotoxicity. Also acibenzolar-S-methyl showed a significant control effect in the field experiment with Chinese cabbage 'Sanchon' in 2000, but the field experiment with Chinese cabbage 'Kangruckyeurum' in 2001 revealed it had phytotoxicity to Chinese cabbage. Such a difference was considered to be caused by differences in phytotoxic reaction of Chinese cabbage cultivars to the chemical. Streptomycin+copper, copper hydroxide and Biokeeper showed 79.7%, 71.9% and 60.9% in control efficacy, respectively, in the field experiment with Chinese cabbage 'Sanchon' in 2002.