紫云英是一种优良的冬季绿肥作物,它具有易种、高产、肥效高、成本低等优点。我县近几年来大部分紫云英田亩产鲜草只有1000公斤左右,亩产紫云英种子不足20公斤。其主要原因之一就是病虫危害所致。白粉病主要危害叶片,发病严重时可使叶片枯死,甚至种荚和茎也受害。一般10月份就发生,12月份逐渐形成发病中心,到3月中、下旬危害最严重、因此对种子产量 Aspen is a good winter green manure crops, it has the advantages of easy planting, high yield, high efficiency, low cost. In recent years, most of the county in Shibuya Yingtian yield fresh grass is only about 1000 kilograms, less than 20 kilograms per mu of Aspen vetiver seed. One of the main reasons is the pests and diseases caused by. The main hazards of powdery mildew leaves, the incidence of serious leaves can be dead, and even seed pods and stems also suffer. Generally occurs in October, December gradually formed the center of disease, by the end of March the most serious harm, so the yield of seeds