木豆是紫胶虫优良寄主植物之一。它具有生长速,投产快,固虫密度大,越冬保种好等优点。但是,这种植物很易遭受白粉病危害。在我场病害蔓延流行期为4—11月,一般以4—6月最为严重。发病时病叶起初出现黄白色斑块,后变为白色粉末状.最后转为褐色。受害叶向上卷缩,使幼叶不能展开而出现新梢回枯现象,严重地影响着紫胶 Pigeon is one of the fine host plants of the genus Iris. It has the growth rate, put into operation fast, solid insect density, overwintering conservation and so on. However, this plant is susceptible to powdery mildew. In my epidemic of disease spread from April to November, usually in April-June is the most serious. Occurrence of diseased leaves at first appeared yellowish white patches, then became white powder. Finally turned brown. Injured leaves curled upward, so that young leaves can not start showing the phenomenon of returning shoots, seriously affecting shellac