一、关于病害流行及予测农林植物的个别植株的病害并无多大的经济意义,只有流行病害才会带来严重的损失。病害流行的主要因素有: 病原因素。只有为数众多韵病原物才能造成广泛的侵染,病原物越冬的数量是次年进行初侵染的基础。但对于能进行多次再侵染的病原,则主要决定于再侵染过程中增殖速度。有时其越冬数量虽不大,但由于潜育期短,每次侵染后产生的孢子数量大,因此,只要条件适 First, there is not much economic significance in respect of the prevalence of diseases and the prediction of diseases of individual plants of agroforestry plants. Only epidemic diseases will bring about serious losses. Disease prevalence of the main factors are: pathogenic factors. Only a large number of rhyme pathogens can cause widespread infection, the number of wintering pathogens is the basis for the initial infection in the following year. However, the pathogen that can be re-infected many times is mainly determined by the rate of proliferation during re-infection. Sometimes the number of overwintering is not large, but due to the short incubation period, the number of spores produced after each infection is large, so long as the conditions suitable