甘肃天水小麦白粉病菌越夏及有性时期在侵染循环中的作用

2007-2009年，在甘肃天水对不同生态条件及海拔高度的小麦白粉病菌进行了闭囊壳形成率观察、模拟病圃试验及越夏调查，结果表明: 小麦白粉病菌有性时期最早在扬花期开始出现，不同抗性类型品种、不同生态条件下出现的迟早和形成量的多少有较大差异。小麦白粉病菌主要以分生孢子在天水市不同海拔高度的自生麦苗上越夏，是当地秋苗发病的初侵染源。二阴山区高海拔地区病叶率高于川道及低海拔地区。闭囊壳在正常年份只侵染自生麦苗，在整个侵染循环中仅起着间接作用。

Over summering of Blumeria graminis f.sp.tritici in Tianshui of Gansu and effects of the sexual stage on infection cycle

The over summering of Blumeria graminis f.sp.tritici was investigated under different ecological conditions and at different altitudes in Tianshui of Gansu Province. The results indicated that the cleistothecia first appeared at flowering stage. There was great difference in appearance time and amounts of formation of cleistothecia on wheats with different levels of resistance and under different ecological conditions. B. graminis could over summer by means of conidia on volunteer wheat seedlings at different altitudes in Tianshui, especially in plains and shady mountains. It was the primary inoculation source of autumn wheat seedlings in these areas. The percent of diseased leaves in high altitude areas was higher than that in low altitude areas. In normal years, the cleistothecia can only infect volunteer wheat seedlings, but not autumn wheat seedlings in plains and shady mountains. It therefore plays an indirect role in infection cycle of wheat powdery mildew.