Studies on the Dwarf Disease of the Mulberry Tree(Transmission by Grafting and Insects)

뽕나무 위축병에 관한 연구(접목전염 및 곤충전염)

A series of experiments were conducted from 1968 to 1970 to find the transmission effects of the dwarf disease of mulberry tree in connection with inlay grafting and insect vector with the following conclusions: 1. The inlay-grafting of sound scions on diseased roots showed a 30 per cent transmission rate among the successful grafts. The inlay-grafting of diseased scions on sound roots showed a 14 per cent transmission rate among the successful grafts ir the case of scions cut and stored before wintering but no transmission effect in the case of scions prepared after wintering, There were some stocks, among the unsuccesful grasfts of diseased scions upon sound roots, that sprouted out new buds, no transmission effects were found in them, 2. Leafhoppers (Hishimonus disciguttus Walker) collected from areas with no dwarf disease infection were grouped into three plots and let to feed on mulberry tree severely infected by dwarf disease for 7 days, 14 days and 21 days respectively. After these preliminary treatment, the leafhoppers were recollected to be fed on the sound seedling divided into three plots for 10 days, 15 days and 20 days respectively to find the transmission effects. The results are that the 7 day plot showed no transmission effect whereas the 14 day plot showed a 22 per cent disease rate and the 21 day plot 61 per cent rate indicating that the longer the feeding period is the higher the transmission rate.

1968년부터 1970년까지 뽕나무위축병에 관하여 접목전염 및 곤충매개전염시험을 한바 결과를 요약하면 다음과 같다. 1. 병근에 건전수목을 절접하므로서 활착주수중 30%의 전염율을 나타냈다. 건전근에 병수목을 절접함에 있어서는 병수목을 월동전에 채취 저장하였다가 익춘 공시한 것은 활착주수중 14%가 전염되였는데 반하여 월동후에 채취한 병수목에 있어서는 전혀 발병되지 않았다. 건전대목에 병수목을 절접하여 불활착된 것 중 대아가 발조한 것은 전혀 발병되지 않았다. 2. 뽕나무위축병의 무병지대에서 채집한 마름무늬매 미충을 중증위축병주에서 7일, 14일, 21일 간식 각각흡즙시킨 성충을 무병실생묘에 방사접종한 결과 7일구는 전염되지 않았으며 14일구는 22％, 21일구는 61％ 전염율을 나타냈다. 흡즙시간과 접종시간은 길수록 전염율이 높았다.