大白菜霜霉病与若干生态因子的关系

RESEARCH ON RELATION BETWEEN SOME ECOLOGICAL FACTORS AND PERONOSPORA PARASITICA (PERS.)FR. ON CHINESE CABBAGE PLANTS

大白菜霜霉病的病原——寄生霜霉(Peronospora parasitica pers.Fr.)孢子囊产生、萌发的速度与温、光密切相关。15—20℃最有利于孢子囊的产生及萌发。在黑暗条件下产孢数量多而且速度快,光照对孢子囊的萌发也有促进作用。在温湿度适宜的条件下,田间罹病植株可全日释放孢子囊,并浮动于大气中,一日内上午孢子囊释放量是下午的3倍。

The formation and germination rates of sporangia of Peronospora parasitica, pathogen of downy mildew on Chinese cabbage plants, are closely related to temperature and light. The optimum temperatures for formation and germination of sporangia are 15—20℃ Dark will help to favor abundant and rapid sporangium production, while light can stimulate germination of sporangium If temperature and humidity are favorable,sporangia will be released all the day from diseased plants in the field and then float in the air. The sporangia released in the morning are 3 times as much as those released in the afternoon.