파드득나물 균핵병균(Sclerotinia sclerotiorum)의 균핵 헝성 및 생존에 미치는 온도의 영향

Sclerotinia rot of C. japonica caused by Sclerotinia sclerotiorum was observed throught the growing season in the vinylhouse at the Namyangiu, Yangju and Yangpyung areas. The disease was commonly occurred at late autumn after transplanting and continuously increased until spring in next year, The disease was especially severe at the Yangpyung area among three areas. Three isolates of S. sclerotiorum obtained from C. japonica in different geographic areas were evaluated for ability of sclerotia formation and viability under different temperature. Temperature for mycelial growth ranged from 5 to 3$0^{\circ}C$, with optimum temperature at 15~3$0^{\circ}C$. Sclerotia were fewer formed at low temperature, but their size was larger than that at high temperature. Small size of sclerotia was more viable than those of large size at high temperature. Based on the differences in viability of sclerotia, the relative ranks of sclerotia were in order ~2 mm > 3~4 mm > 5 mm~. 남양주, 양주, 양평에서 파드득나물 균핵병의 발생생태를 조사한 결과, 균핵병은 늦가을부터 초봄까지 주로 동계기간에 발생했으며, 지역별로는 양평에서 발생이 심했다. 포장에서 분리한 파드득나물 균핵병균은 기보고된 Sclerotinia sclerotiorum의 균학적 특성과 일치하였고, 균사생장은 5~3$0^{\circ}C$에서 이루어졌으며, 15~3$0^{\circ}C$에서 활발하게 생장하였다 균핵형성은 20~$25^{\circ}C$에서 많이 형성되었으며, 낮은 온도에서 형성된 균핵의 크기가 큰 경향이었다. 균핵생존율은 균핵크기가 작을수록(~2 mm > 3~4 mm > 5 mm~) 높았으며, 치상온도에서의 정치시간이 길수록 높게 나타났다.