1.黄化落叶这是目前发生最普遍,危害最严重的一种生理落叶。其特点是在夏秋多雨年份,枝条基部先出现块斑状褪绿现象,逐步使叶片变黄、变薄、变小而脱落。这些基部小叶早期黄化脱落是正常的,它们本身极少制造营养,是一些消耗型的叶片。这种类型的叶片脱落不必采取任何防治措施。 1. Yellow leaves This is the most common occurrence, the most serious damage to a physiological deciduous. It is characterized by rainy summer and autumn, the first branch of the base patchy chlorotic phenomenon, and gradually make the leaves turn yellow, thinner, smaller and fall off. Early shedding of these basal leaflets is normal, they produce very little nutrition itself, is some consumption-type leaves. This type of leaves off without taking any preventive measures.