一、白粉病4-5月染病叶初期出现近圆形或不规则形块状退绿病斑,随着病斑逐渐扩大。嫩枝、嫩叶被害表面布满灰白色粉状物,发生严重时,幼芽和嫩叶不能伸长,绉缩卷曲,凹凸不平,叶色缺绿,影响生长发育,甚至引起早期落叶。到秋季病斑颜色转淡,并在其上产生初为黄白色,后变为黄褐色,最后变为黑褐色的小颗粒状物。防治方法:1.清除有病的枝 First, the powdery mildew April-May early emergence of nearly circular or irregular shaped block-like green spots, with the lesion gradually expanded. Shoots, young leaves are covered with gray powder victim surface, in severe cases, young shoots and leaves can not be elongated, crepe curly, uneven, lack of green leaves, affecting growth and development, and even cause early deciduous. The lesion color fades to autumn and produces a small pellet that turns yellowish-white at first, then turns brown, and finally turns dark brown. Prevention and treatment methods: 1. Clear the sick branches