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1981至1983年进行了白菜霜霉病的初次侵染来源与侵染过程的研究。试验证实,该病的初次侵染来源来自病叶内的卵孢子和带病种子。接种试验表明,病叶内卵孢子经室内保存及冰箱处理或室外越冬后分别进行定量接种,结果幼苗均易发病,并表现有限系统侵染,与播种带病种子出现的病苗症状相同。经组织解剖均发现病子叶与病茎内有大量菌丝和吸器,说明病种子内存在潜伏菌丝,一般感病品种带菌率较高。室内卵孢子发芽试验亦获得成功,卵孢子发芽前用流水冲洗7～9天,发芽适温25℃,用糠醛(100微升/升)可控制污染。用病菌孢子囊接种离体叶和幼苗进行侵染过程观察,同样发现在细胞间隙发育的菌丝,并产生吸器。离体叶培养也是保存菌源的较好方法,保存时间可达15～20天。
From 1981 to 1983, the origin and process of primary infection of cabbage downy mildew were studied. Tests confirmed that the initial source of infection from the diseased leaves of oospores and diseased seeds. Inoculation tests showed that the oocysts in diseased leaves were quantitatively inoculated separately after being stored indoors and after refrigerator treatment or outdoor wintering. As a result, seedlings were susceptible to disease and showed limited systemic infection, which was the same as that of diseased seedlings sown with diseased seeds. Tissue dissection were found in the diseased leaves and diseased stems have a large number of mycelium and suction device, indicating that there is latent in the diseased seeds mycelium, the general susceptible varieties with higher rates. Indoor spore germination test has also been successful, spore germination before running flush with water for 7 to 9 days, germination temperature 25 ℃, furfural (100 μl / l) can be controlled pollution. Inoculation of the in vitro leaf and seedlings with the sporocytosis of the bacteria was observed for the infection process and the hyphae were also found to develop in the intercellular space and produce the aspirate. In vitro leaf culture is also a good way to save bacteria, save up to 15 to 20 days.