Disease Incidences in Radish and Chinese Cabbage. I. Major Diseases in Radish and Chinese Cabbage grown in Alpine Areas in Jeonbug Province

고냉지단경기채소(무우. 배추) 및 평야지 추작채소단지에 발생하는 주요병해조사 I. 전북고냉지단경기 무우, 배추 주요병해

Vegetables including Chinese cabbage and radish have been grown in alpine areas such as Muju, Namweon, Jinan and Jangsu during the shortage period of vegetables. The incidence of various diseases, environmental factors such as temperatures and rainfalls, and aphid populations as virus vector were observed at 10-day intervals from July to September in those areas. Disease incidence showed no significant difference among locations. Major diseases in Chin ese cabbage were bacterial soft rot, white spot, downy mildew, mosaic virus, Alternaria leaf spot and Fusarium seedling blight. Major diseases in radish were virus, white rust, black rot, root rot, leaf spot and Fusarium seedling blight. Disease incidence reached peak on Aug. 20 with $27\%$ infection in radish and with $20\%$ infection in Chinese cabbage during the growing season, and declined thereafter. Percentage of infection in each growth stage showed $25\%$ at root thickening stage and $26\%$ at the harvest time in radish; and the head formation stage, $24\%$ at the harvest time. The data indicate that disease incidence in radish increased rapidly at late growing stage and progressively increased in Chinese cabbage Seedling blight caused by Fusarium sp. and root rot caused by Aphanomyces sp. were also observed in those areas. Cool and wet weather appeared to be favorable for disease incidences during the rainy period of growing season although average temperature was about $25^{\circ}C$. Populations of aphids were lower in the alpine vegetable growing area than that of flat areas. Aphids as virus vectors from total aphids collected were $73.5\%$ or 289 virus vectors /993 total aphids in Namweon and $18.1\%$ or 31 virus vectors/171 total aphids in Muju. The most prerevalent species of aphids was Myzus persicae Sulz.

전북고냉지 단경기채소단지인 무주, 남원, 진안, 장수지역의 무우, 배추 재배포장에 대한 병해발생, 기상관계, 매개진딧물 밀도등을 조사하였다. 7월부터 9월까지 순별로 조사한 결과는 다음과 같다. 발병상황은 지역적 특이성이 없고 비슷하였다. 배추의 주요병해는 흰빛썩음병, 흰무늬병, 노균병, virus병 검은무늬병 Fusarium에 의한 입고현상등이고, 무우에서는 바이러스명병, 흰녹가루병, 검은빛썩음병, 흰빛썩음병 검은 무늬병, Fusarium에 의한 입고현상등의 피해가 나타나고 있다. 발병상황을 시기적으로 보면 8월 20일경이 최고발병기이였다. 무는 총감염율이 $27\%$ 이고, 그후 점차 감소하였으나, 배추는 $20\%$의 감염상태가 계속 지속된다. 장기별 발병상황은 무우는 비대기 $25\%$, 수확기 $26\%$로 후반기에 급증한다. 배추는 초기생장기부터 계속적인 발병증가를 나타내여 결구기수확기 $20\%$의 총감염율을 나타낸다. 외국에서 보고된 Fusarium이 의한 입고현상과 Aphanomyces에 의한 근부병이 조사지역에 발병되고 있었다. 기상환경은 채소생장기간의 평균최고온도가 $25^{\circ}C$ 정도이나 우기가 겹치고, 냉량다습하여 발병의 유인적환경이였다. 매개진딧물의 분포밀도는 평난지보다 낮으며 총진딧물 대비 매개진딧물은 남원이 $73.53\%(289/393)$로 많고, 무주가 $18.12\%(31/171)$로 제일 낮았다. 매개진딧물중 우점종은 복숭아혹진딧물(Myzus persicae)이였다.