水杉(Metasequoia glyptostroboides Hu et Cheng)是四十年代我省从鄂西引进新发现的绿化造林树种。它有适应性强、生长快、干形直、树形优美等特点,深受群众喜爱,是一种良好的绿化树种。惟易感染赤枯病(Pestalotia funerea Desm)是其一大弱点。根据1984年在省内七个县调查,感病指数为24.0—81.0,病株与健康株材积生长有明显差异,健壮株年高生长50—80厘米,粗生长1—2厘米;而病株年高生长10—20厘米,粗生长仅0.1—0.2厘米。1984—1986年,我们对水杉赤枯病进行了研究,现将研究结果报道如下。 一、病害分布与危害 1981年,在森林病虫普查时,苏州地区发现有些水杉感染赤枯病。1984年调查,仪征、江都、太仓、吴县、东台、大丰、射阳等县,水杉赤枯病普遍发生,发生面积占各地水杉面积的20—50％,发病率为24.1—100％(表1)。感病轻的植株生长缓慢,较重的形成“小老树”,少数濒临死亡。调查中, Metasequoia glyptostroboides Hu et Cheng is a newly introduced afforestation species introduced from western Hubei in the 1940s. It has strong adaptability, fast growth, dry straight, beautiful tree and other characteristics, loved by the masses, is a good green tree species. However, Pestalotia funerea Desm is a major weakness. According to the survey in seven counties in the province in 1984, the susceptibility index was 24.0-81.0. There was a significant difference in the volume growth of diseased and healthy plants. The healthy plants grew 50-80 cm in height and grew 1-2 cm in diameter, while the diseased plants Growth of 10-20 cm high, coarse growth of only 0.1-0.2 cm. 1984-1986, we carried on the study of the dry weight of redwood, the research result is reported as follows now. First, the distribution and damage of disease 1981, in the forest census, Suzhou found some redwood wilt infection. 1984 survey, Yizheng, Jiangdu, Taicang, Wuxian, Dongtai, Dafeng, Sheyang and other counties, dry red withered disease occurs generally, occurring area accounted for 20-50% of the metasequoia area, the incidence was 24.1-100% (Table 1). Sick light plants grow slowly, heavier form “small trees”, a handful of dying. Survey,