关中小麦白粉病发生规律研究

1983～1991年的研究表明,白粉病菌主要在凉爽阴湿的沿山地区自生麦苗上越夏;夏季多雨凉爽年份,在平原秋作物覆盖地自生麦苗上偶尔也有零星白粉病发生。浸染自生麦苗的菌源,主要是夏季存活期内的有性世代,病残体上的分生孢子无作用。自生麦苗上的分生孢子,是侵染冬麦秋苗的来源;12月上旬停止侵染。秋苗上的菌丛,12月上旬停止产孢,下旬菌丝停止生长,以菌丝主要在茎基叶鞘上越冬;2月上旬菌丝复苏,3月份是病害开始发展期,4月份是普发期,5月份是盛发期;春季病情与雨量、雨日密切相关。

The Laws of Occurence of Powdery Mildew of Wheat in Central Area of Shaanxi Province

The 1983~1991 years studies indicated that the fungus overwintered on voluntary seedlings of wheat mainly in the cool and wet areas along the mountains.and that occidentally the sporadic powdery mildew occured on voluntary seedlings of wheat in the field covered by crops when rainy and cool in summer. The fungous source to infect voluntary seedlings of wheat is mainly cleistothcia on the diseased survival in the limited period lived in summer,and the conidia on the diseased survival are not of effective. The conidia on voluntary seedlings of wheat are source to infect seedling of wheat in autumn,and the lungus stops infection to the seedlings in the first decade of December. The colonies on autumn seedlings of wheat stop sporulation in the first decade of December,and stop growing in the third decade of December. The fungus overwintered with hyphae mainly on leaves sheath of stem base of wheat. The hyphae recover growth in the first decade of February. The beginning development period of the disease was in March,and the disease occured generally in April and greatly in May. The development of the disease was closely related to rainfall and rainy days in spring.