Bacillus stearothermophilus YC4194에 의한 Pythium 모잘록병의 생물학적 방제

In vitro and in vivo activities of a biocontrol agent, Bacillus stearothermophilus strain YC4194 was evaluated for the control of Pythium damping-off of cucumber. B. stearothermophilus YC4194 inhibited germination of cystospores and formation of zoosporangia of Pythium aphanidermatum in vitro. Incorporation of a bentonite and talc based formulation(10$^{9}$ cfu/g) of B. stearothermophilus YC4194 to the nursery soils (10 g/ι soil) resulted In a significant (p=0.01) reduction in the disease severity of cucumber damping-off after inoculation with P. aphanidermatum. The control efficacy of B. stearothermophilus YC4194 formulation was not different from that of the fungicides, dimethomorph, metalaxyl, ethaboxam. When the cucumber plants were transplanted to the soil inoculated with P. aphanidermatum zoospores, the B. stearothermophilus YC4194 maintained the high population density in rhizosphere soil upto 10$^{7}$ cfu/g until 15 days after treatment. Bacillus stearothermophilus YC4l94는 in vitro 와 in vivo 에서 병원균 Pythium aphanidermatum에 대한 억제 효과를 보였다 in vitro 실험에서 P. aphanidermatum의 유주포자낭 형성과 피낭포자 발아를 억제하였을 뿐 아니라 식물체에 적접 길항균 제제 처리 시 50% 이상의 방제가를 보였다. 그리고 다른 화학 살균제와 비슷한 방제효과를 보여 미생물 제제로서의 개발 가능성을 보여주었다.