向日葵霜霉病六十年代在我国初见,目前仅在黑龙江、吉林和新疆有过报道。据观察,向日葵霜霉菌Plasmopara halstedii(Ferlow)的侵染方式,以苗期的系统侵染为主,在成株期病菌又可反复再侵染。受侵的幼苗,重者枯死,轻者生长矮化、畸形、花盘瘦小,产量降低。 根据我们1980—1981年观察,发现凡是重茬的连作地块发病都重,而换茬或新垦种植的地则病情都轻。考虑到霜霉病的发生量 Sunflower mildew mildew first saw in our country in the sixties, at present only in Heilongjiang, Jilin and Xinjiang have been reported. It is observed that the sunflower downy mildew Plasmopara halstedii (Ferlow) of the way of infection, mainly in the seedling stage of the system of infection, in the adult plant pathogen and then repeated re-infection. Invaded seedlings, severe cases of withered, light dwarf growth, deformity, faceplate thin, lower yields. According to our observations in 1980-1981, it was found that all the continuous cropping plots were heavily affected, while those for replacement or cultivation were light. Taking into account the occurrence of downy mildew