白粉病是一种发生普遍、症状显著、分布广泛的病害,为害所有种类,如禾谷类和禾草、蔬菜、观赏植物、杂草、灌木、果树及森林树木。本期将白粉病作为一大类观赏植物病害向读者介绍,使读者对其有系统、全面的了解和认识。白粉病发生后,植物的叶片、嫩枝、花、花柄和新梢都可受害。叶上初为褪绿斑(此过程有时不明显),继而可见白色菌丝层,菌丝层上产生白粉状分生孢子,使叶片有点片状发生的白粉状斑块,生长季节,白 Powdery mildew is a widespread, symptomatic and widespread disease that affects all species, such as cereals and grasses, vegetables, ornamental plants, weeds, shrubs, fruit trees and forest trees. In this issue, powdery mildew is introduced to the readers as a major ornamental plant disease so that readers can systematically and comprehensively understand and recognize them. Powdery mildew occurs, plant leaves, twigs, flowers, flower stalks and shoots can suffer. Leaf early chlorotic spot (this process is sometimes not obvious), then visible white mycelium layer, mycelium layer of white powdery conidia, the leaves a little flaky white powdery plaque, the growing season, White