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根据对采自江、浙、黔、川、滇等省部分产桔区的病叶进行分离培养和接种的研究,证明上述各地都有柑桔脂点黄斑病发生。本病症状初呈黄斑,后转为脂斑,有时可进而转变成褐色小园星。病原菌为柑桔球腔菌(My-cosphaerella citri Whiteside),无性阶段为柑桔灰色疣丝孢(Stenella citri-grisea(Fisher)Sivanesan),其主要形态特征与J.O.Whiteside报道的美国佛罗里达州柑桔脂斑病病原菌基本相同,但接种后表现的病状有所差异。病菌的假囊壳产生在落地将朽的病叶上,子囊孢子起着初侵染作用;发生在落叶上的分生孢子数量很少,看来再侵染作用不大,但在培养基上可产生较多的无性孢子.接种表明,病菌从寄主的气孔侵入,潜育期1～2个月以上,其长短与柑桔品种有关,在江苏太湖桔区,此菌主要以菌丝体在病叶中越冬,翌年4—9月间落叶上产生子囊孢子传播侵染,春、夏、秋、梢的新叶均可受害,以春梢叶片被害最重.
According to the research on diseased leaves collected from some orange producing areas in Jiangsu, Zhejiang, Guizhou, Sichuan and Yunnan provinces, etc., it is proved that all the above places have the occurrence of citrus yellow spot. Symptoms of the disease showed a macular at first, then converted to fat spots, and then sometimes turn into a small brown garden star. The pathogen is Mycosphaerella citri Whiteside and the vegetative stage is Stenella citri-grisea (Fisher) Sivanesan. Its main morphological characteristics are similar to those reported by JOWhiteside Pathogen pathogens are basically the same, but the performance of the symptoms after vaccination are different. Bacterial pseudohypacarp shell occurs on the floor will be rotten leaves, ascospores play an initial role in infection; occurred in the deciduous on the number of conidia, it seems little re-infection, but on the medium Can produce more asexual spores. Inoculation shows that the bacteria invade the stomata from the host, the incubation period of 1 to 2 months or more, the length and citrus varieties in the Taihu Lake in Jiangsu Province, the main mycelium in mycelium Overwintering sick leaves, the following year from April to September on the leaves of ascospores produce infection spread, spring, summer, autumn, shoot new leaves can be victimized by the spring shoots the most victims.