病原菌在繁殖和传播方式上各各不同,作物的抗性一般只对病原菌的繁殖过程产生影响,而对其传播行为不起作用。一些病原菌在寄主的每一生长季节里只有一个繁殖周期,如谷类作物的黑穗病和腥黑穗病,而有些病原菌则可有多个繁殖周期,如谷类作物的锈病,水稻稻瘟病等.Vanderplank (1963)把属于后一种类型的病害称为“复利病害”。这种具有多个繁殖周期的病害依据Xt=Xo~(ert) Pathogens vary widely in their mode of reproduction and transmission. The resistance of crops generally affects only the pathogen’s reproduction and does not contribute to their transmission. Some pathogens have only one breeding cycle in each host’s growing season, such as smut and taupe in cereal crops, while some may have multiple breeding cycles, such as rust in cereal crops and rice blast. Vanderplank (1963) refers to the latter type of disease as “compound disease.” The disease with multiple breeding cycles according to Xt = Xo ~ (ert)