[Objective] The aim was to study the bacterial carrying seeds as the primary infection sourcs of Cunularia leaf spot of maize, and to provide the theo-retical basis for the control of the disease in production. [ Method] Through slide germination and seed tissue isolation method, the viabilities of seeds with internaland external bacterial carrying were detected ; the infection of bacterial carrying of seeds on the young seedling was detected indoors by sand culture method ; and the infection of bacterial carrying seeds on maize was detected using field cultivation method. [Result] The conidia of Gunularia and mycelia carried by maize seeds could survive through the winter. Intemal bacterial carrying of seed affected the germination of seeds, but external bacterial carrying did not affect the germination; internal and external bacterial carrying seeds could infect the radicle and gemmule of maize seedling. [Condusion] The conidia of Curvularia and mycelia carried by maize＇seeds could survive through the winter and infect the seedling, which would make the seedlings have weak growth.
