Studies on Mulberry Shoot Rot caused by Fusarium spp.

Fusarium spp. 균에 의한 뽕나무신소썩음병에 관한 연구

Isolation and pathogenicity of Fusarium spp. from mulberry shoot rot and severity of diseases which were known as bacterial blight were examined on four mulberry varieties in Suwon, Kongju and Chuncheon, A symptom of mulberry shoot rot was initiated long brown spot on young leaves and shoots. It was developed into dark brown spot and produced white mycelia and spores on the diseased symptoms. A symptom of bacterial blight showed leaf rolling and water soaking spot and produced bacterial ooze on leaf and shoot However later stage of upper two types of symptom was hardly distinguished. Severities of shoot rot and bacterial blight were 7.5% and 4.4% in Suwon, respectively. Isolation of Fusarium spp. on shoot rot symptoms was highter than that on bacterial blight symptoms, but isolation of Pseudomonas spp. was higher on bacterial blight symptoms. Trends of pathogenicity of Fusarium spp. and Pseudomonas spp. were similar to inoculation works, and isolations of pathogenic Fusarium spp. from center of symptom was higher than that from 30cm of symptom of all samples in three cultivation areas. Disease severities of shoot rot on variety of Kaeryangppong were 13.9%, 15.9% and 17.2% in Suwon, Kongju and Chuncheon, respectively. However variety of Cheongolppong was highly resistant to shoot rot disease in three cultivation areas.

축엽세균병으로 알려진 피해뽕나무에서 진균인 Fusarium spp. 균이 분리되어 이를 구명하고 그 피해정도를 조사한 결과 1. 신소썩음증상은 세로로 긴 갈색의 병무늬가 시간이 경과할 수록 암갈색으로 변하고 흰곰팡이가 생기며, 축엽세균병증상은 잎이 말리고 신소에 수침상의 병반과 bacterial ooze가 보인다. 그러나 시간이 경과하면 구분이 어렵다. 2. 신소썩음증상의 피해율은 7.5%, 축엽세균병의 피해율은 4.4%였다. 3. Fusarium spp. 균의 분리는 신소썩음증상에서 높았고, Pseudomonas균의 분리는 축엽세균병 증상에서 많았다. 또한 병원성도 같은 경향을 보였다. 4. 수원 등 3지역 모두에서 부위별 병원성 Fusarium spp. 균의 분리율은 병반에서 30cm 부위에서 보다 병진전부위에서 더 높았다. 5. 수원 등 3지역 모두에서 개량뽕의 신소썩음증상 피해가 가장 많았다. 그러나 청올뽕의 신소썩음증상 피해는 조사 품종중에 가장 적었다.