目前,对病害判断不准确、盲目用药现象十分普遍,如何对病害进行诊断是非常必要的。通常我们以导致植物病害发生的两种因素分为侵染性病害和非侵染性病害。侵染性病害是由病原生物引起的病害,包括真菌、细菌、病毒、线虫等病原生物,这类病害的特点是可以相互传染,这也是与非侵染性病害最大的区别。侵染性病害有三个特点:一是它有一个不是特别明显的发病中心;二是在特定的品种或环境条件下,发病程度轻重不一;三是在病斑处可发 At present, judging disease is not accurate, the phenomenon of blind medication is very common, how to diagnose the disease is very necessary. Generally, we divide the two factors that lead to the occurrence of plant diseases into infectious diseases and non-infectious diseases. Infectious diseases are diseases caused by pathogens, including fungi, bacteria, viruses, nematodes and other pathogens. These diseases are characterized by mutual transmission, which is also the biggest difference with non-invasive diseases. Infectious diseases have three characteristics: First, it has a not particularly obvious center of disease; Second, under specific breed or environmental conditions, the severity of the disease varies; Third, the lesions can be made at