Bacillus amyloliquefaciens M27에 의한 오이 흰가루병의 생물적 방제

Abstract

흰가루병균(Podosphaera fusca)에 의한 오이 흰가루병의 생물적 방제를 위하여 검정한 길항세균 B. amyloliquefaciens M27 균주는 4.0% 흰가루병이 발생하였고 무처리는 80.5% 발생하였다. MH와 LB배지에서 배양한 B. amyloliquefaciens M27 균주의 배양여액은 TSB, NB와 KB배지에서 배양한 배양여액보다 오이 흰가루병 방제효과가 우수하였다. M27 균주를 LB배지에서 배양한 배양여액 2, 5, 10, 20, 50배와 100배 처리한 경우 오이 흰가루병이 0%, 0%, 0%, 1.3%, 3.1%, 5.0%와 33.3%를 나타낸 반면에 무처리는 60.0%를 나타내었다. 7월, 10월과 12월에 오이 흰가루병이 발생할 때 LB배지에서 배양한 M27균주의 배양여액를 10배로 처리한 결과 88.9~98.9% 방제효과를 나타났다. 이와 같은 결과에서 B. amyloliquefaciens M27 균주의 배양여액은 오이 흰가루병에 방제에 매우 효과적이었다. Bacillus amyloliquefaciens M27 was isolated from the cotton-waste compost for cultivation of oyster mushroom (Pleurotus ostreatus). B. amyloliquefaciens M27 is a biocontrol agent with antagonistic activities against a wide range of fungal pathogens. The aim of this work was to evaluate the possibility of exploiting antagonistic bacteria, B. amyloliquefaciens M27, in the biological control of the cucumber powdery mildew fungus, Podosphaera fusca. In greenhouse tests, the isolate was found to be very effective to control powdery mildew on cucumber leaves showing 4.0% diseased area, whereas diseased area in the control was 80.5%. The filtrate of the isolate cultured on MH and LB media were more effective for control of the disease than those cultured on TSB, NB, and KB media. When two, five, ten, 20, 50 and 100-fold diluted culture broth of isolate on LB media were treated, disease areas were 0%, 0%, 0%, 1.3%, 3.1% and 5.0%, respectively, whereas diseased area in the control was 60.0%. The filtrate of the isolate cultured on LB media was treated to cucumber plants on July, October and December just before the outbreak of the powdery mildew occurred. When 10-fold diluted filtrate of the isolate was treated, control efficacy was 88.9~98.9% in the treated seasons. The results showed that the culture filtrate of B. amyloliquefaciens M27 was very effective to control powdery mildew of cucumber.