• The Korean Journal of Pesticide Science
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• v.19 no.2
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• pp.119-124
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• 2015

Bacterial leaf spot, caused by Pseudomonas syringae pv. syrinage, is a very damaging disease to green pumpkin in Gong-ju and Non-san nursery. However, there is no good method to control the disease in Korea. Growth inhibition of pathogen on medium, control efficacy on seedling stage, and seed treatment effect of 6 anti-bacterial pesticides were investigated for selection of the best pesticide for seed treatment and control of the disease. Growth inhibition zone on King's B medium were the largest by oxytetracycline 170 ppm and oxytetracycline 15 ppm + streptomycin sulfate 188 ppm, oxolinic acid 200 ppm, streptomycin 200 ppm were next respectively. Control efficacy of oxytetracycline 1.5% + streptomycin sulfate 18.8% WP and oxytetracycline 17% WP on seedling stage were 71.4% and 49.4%, respectively. Seed treatment of oxytetracycline 15 ppm + streptomycin sulfate 188 ppm on the artificially inoculated seeds inhibits pathogen growth completely from the treated seeds and 96% control efficacy on grow-out test of the treated seeds. Seed treatment of streptomycin 100 ppm (2,000 dilution of streptomycin 20%) on the artificially inoculated seeds allow 280 cfu/g of pathogen growth from the treated seeds and 60% control efficacy on grow-out test of the treated seeds. Seed treatment of oxytetracycline 85 ppm (2000 dilution of oxytetracycline 17% WP) on the artificially inoculated seeds allow 80 cfu/g of pathogen growth from the treated seeds and 90% control efficacy on grow-out test of the treated seeds. These results suggested that oxytetracycline 1.5% + streptomycin sulfate 18.8% WP was the best pesticide for seed treatment to control of the bacterial spot disease by Pseudomonas syringae pv. syringae.