การคัดแยกเชื้อ Streptomyces spp. ที่มีคุณสมบัติในการยับยั้งโรคราน้ำค้างสแคบและราสนิมในองุ่น

บทคัดย่อ

The objective of this study was to select effective antagonists to be used as biocontrol agents for grapedowny mildew, scab and rust. Streptomyces spp. were isolated from soils collected from grape growing areas inNakhon Ratchasima and Ubonratchathanee provinces. From the soils, 73 isolates of Streptomyces spp. antagonisticto P. aphanidermatum, C. ampelinum and S. rolfsii were obtained.Subsequently, the top 5 isolates that were mosteffective in reducing the growth of Pythium aphanidermatum, Colletotrichum ampelinum and Sclerotium rolfsii indual culture were selected for further test with downy mildew, scab (anthracnose), and rust on the detached grapeleaves. It was found that Streptomyces isolate SHH202 at log phase; SHR103 at stationary phase as cell suspension;SYR107 at log phase and SSR107 at stationary phase as culture filtrate were most effective against downy mildew,isolate SHH202 at both phases as cell suspension; at log phase as culture filtrate and SYR107 at stationary phase asculture filtrate were most effective against scab, isolate SSH216 at log phase and SSH211 at stationary phase as both forms were most effective against rust. These isolates had different capacity in subduing downy mildew, scab, andrust depending on the isolate, growth phase and the form tested.