白粉病是瓜类作物常见病害之一。主要发生在瓜的叶片上，也危害茎蔓及叶柄。多发生在瓜类生长中、后期。初发病时，叶片或茎蔓上出现白色圆形的小霉点，以叶正面为多，逐渐向四周扩展，形成整叶白色霉斑。瓜类白粉病是一种由子囊菌引起的植物病害。病菌附于植株残体遗留在土壤 Powdery mildew is one of the common diseases of melon crops. Mainly occurs in the leaves of melons, but also endanger the stems and petioles. Occurred in the melon growth, late. The first incidence, the leaves or stems appear on the white round moldy point to the front of the leaf as much, gradually expanded to the surrounding to form a whole leaf white mold. Melon powdery mildew is a plant disease caused by Ascomycetes. Bacteria attached to plant residues left in the soil