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早稻病草回田后,浸在田水里病草中稻瘟病菌的存活期为3～7天,埋在田土下1～3寸处为1天,有灭菌防病的作用;不回田弃置或堆放田间存活期达41～71天以上,可为晚稻发病的菌源。晚稻病草回田,耕翻土下,埋在塘泥中,复盖紫云英和散在冬闲田上,除复盖紫云英少数架在稻桩上离开地面的病草外,均不可能成为翌年早稻发病的初侵染源。晚稻稻草堆表面病草中的稻瘟病菌存活期达168天以上,为翌年早稻发病的重要菌源。在大气湿度较高的阈北地区,室内早稻干燥病草中稻瘟病菌的存活期为10～12个月,晚稻为13～16个月之间。前者可为翌年早稻,后者不仅为翌年早稻,还为晚稻全生育期提供发病的茵源。文中还对早稻病草回田后病草中稻瘟病菌迅速死亡的原因作了分析和讨论。
Early rice disease grass back to the field, immersed in water field sick grass Magnaporthe grisea survival period of 3 to 7 days, buried in the field 1 to 3 inches at 1 day, the role of sterilization and disease prevention; do not back to the field Disposal or storage of field survival of 41 to 71 days or more, for late rice pathogens. Late rice sick grass back to Tian, plowing the soil, buried in the pond mud, covered with aspartame and scattered in the winter fallow field, in addition to cover a small number of shelled asparagus in the pile of grass on the ground to leave the disease, are unlikely to become the following year Initial infection of early rice. The survival rate of M. grisea in the grasses of late rice paddies was over 168 days, which was the important source of early rice in the following year. In the north of the region with high atmospheric humidity, the survival period of Magnaporthe grisea in the early-season dry grass of indoor is 10-12 months and that of late rice is 13-16 months. The former can be the following year early rice, the latter not only for the following year early rice, but also for the late rice throughout the growing period to provide the source of the disease. The article also analyzed and discussed the reasons for the rapid death of rice blast fungus in the grass of early rice after returning to field.