Studies on the Occurrence of Corn Sheath Blight Caused by Rhizoctonia solsni I. Influence of growth season and cultural environment on the occurrence of sheath blight disease.

담근먹이 옥수수의 잎집무늬마름병 발생에 관한 연구 I. 생육시기 및 재배환경과 잎집무늬 마름병 발생

The investigation was carried out to identify the main pathogen infected with sheath blight in corn plant during 1986-1987. The main fungi of sheath blight isolated from corn plant was identified as Rhizoctonia sobni. Sheath blight in corn plant was first found in early July and infected extremely from late July to end August. Severe sheath blight disease was observed in Gyeongido (Yeoju and Suweon) and Jeonnam (Kwangju) area. The rate of attack was associatied with management and cultural environments of corn plant. Dense planting increased sheath blight, but application of cattle compost reduced the rate of infection. A positive correlation was found between infection rate of shealth blight and concentration of soluble carbohydrate in corn plant (r=0.96). The varieties of Jinjuok, Suweon 83, Suweon 87, Suweon 89, P.3055, P.3160, DK689 and XCG 51 showed remarkable tolerance to sheath blight disease.