许多科学家调查了松萎病发生和流行的规律。现已普遍认为松材线虫Bursaphelenchus xylophilus(Steiner et Buhrer)NickIe是该病的病原体。1971年Kiyohara和Tokushige用流行病学证实了松材线虫的致病力,并提出了引起松萎蔫病的一些其它因素,包括真菌和空气污染。目前,空气污染,特别是酸雨,是欧洲和北美一些国家引起森林衰退(Evans,1982; Many scientists have investigated the occurrence and prevalence of wilt disease. It is now widely accepted that Bursaphelenchus xylophilus (Steiner et Buhrer) NickIe is the causative agent of the disease. In 1971 Kiyohara and Tokushige used epidemiology to confirm the virulence of pine wood nematodes and proposed some other factors that cause pine wilt disease, including fungal and air pollution. At present, air pollution, especially acid rain, is causing forest decay in some countries in Europe and North America (Evans, 1982;