鐘麻根瘤線蟲病與D-D施用之效果（第一報）

Abstract

Nematode root knot occassionaly causes a serious damage to such economic crops as tobacco, jute, kenaf, etc. grown in the sandy soil in Formasa. This paper gives the results of the experiments on the effects of D-D mixture (dichloropropylene dichloropropane) on nematode root knot of kenaf caused by Heterodera marioni (Cornu) Goodey, which were carried out in Tainan Experiment Station, Taiwan Agricultural Research Institute, Taiwan, China, in 1954. The results of the investigation show as follows: 1. D-D dosages were used at the rates of 255,322 and 377 lits. per hectare. The percentage of serious infestation two and four months after seedieg was respectively 23.23 and 100 in the control, and 0-0.83 and 27.0-41.25 in the treated plots (tables 1 and 2). Population of root knot nematode was reduced greatly by use of D-D. 2. At the time of seed-harvest the survival number was 11.25 per plot (0.2 are) in the control and 111.60-121.75 in the treated plots, yield of seed being 15.83 and 288.60-410.25 gms., respectively (tables 5 and 7). By this means it is possible to harvest the seed abundantly from the sandy soil which may be densely populated by root-knot nematodes if D-D is not used. 3. The height of the plants in the plots treated with D-D was 1.53-1.63 times as high as that in the control, when observation was made four months after seeding (table 3). 4. The outbreak of sclerotium disease and anthracnose of kenaf was parallel with the infestation of nematode root knot (table 5). In this farm, death of kenaf is mainly caused by nematode root knot, but this may also induce the sclerotium disease and anthracnose.