Abstract
This study was carried out to assay the disease incidence degree of Sclerotium rot caused by Sclerotium rolfsii in sixteen most popular commercial cultivars of sweet potato (Ipomoea batatas) in Republic of Korea. The degree of disease incidence was evaluated on pot experiments. In pot experiments using artificial inoculation, the Sclerotium rolfsii caused a stem rot on seedling of sweet potato plants and causes a crown rot on lower stems near or at the soil line at favorable environmental conditions. White mycelial mats and sclerotia were formed at the infection sites. Plants severely infected were fell over or died because lower stems near soil surface were rotten. The degree of disease incidence was varied according to cultivars. Two cultivars, Bio-mi and Deayumi, were very resistant, while five cultivars, Shinjami, Shingeonmi, Hongmi, Yeonjami, and Shinhung-3 were highly susceptible.
고구마 흰비단병 증상에서 분리한 병원균을 이용하여 고구마 품종간 발생차이를 비교하였다. 병원균 접종 후 고구마는 지제부가 수침상으로 변하며 고구마 묘가 꺾여 고사하였다. 병반부위에 흰색균사가 솜털처럼 발생하였고 시간이 경과함에 따라 갈색을 띤 구형의 균핵이 많이 형성되었으며, 흰비단병 특유의 clamp connection이 관찰되었다. 고구마 16품종에 대한 흰비단병 저항성을 비교한 결과 품종간의 차이를 보였으며 특히 대유미와 바이오미에서 높은 저항성을 보였으며 신자미, 신건미, 홍미, 연자미와 신형 3호 등 5종에서 감수성을 보였다.
