玉米茎腐病原菌侵染及发病与玉米生育期的关系

对玉米茎腐病病原菌侵染和发病始盛期与玉米生育期关系进行了５ａ研究，结果表明，玉米出苗后３ｄ就已被茎腐病原菌侵染，根部呈褐色病斑，植株矮小，叶片变黄。播种期接种较常规期接种发病高。玉米茎腐病发病始、盛期都在玉米灌浆后出现。在调查玉米茎腐病和采集病株标本时，可根据玉米灌浆期预测茎腐病的显症期及发病盛期，确定调查适宜时期。

Relationship Between Infection of Pathogens Involved in Causing Corn Stalk Rot and the Growth Stages of Corn

Corn stalk rot, caused by Fusarium graminearum, F. moniliforme and Pythium sp, is a major disease in corn growing areas in our country. Studies were conducted over a fiveyear period to determine the relationship between infection induced by the pathogens, beginning and peak of the disease and the growth stages of the corn plants. The results showed that corn plants were infected by the pathogens 3 days after germination. Symptoms observed on the diseased corn plants included: brown spots on the roots, dwarfing plants, and yellow leaves.Inoculating at seeding resulted in a higher incidence of corn stalk rot than did conventional inoculating at the tasseling stage. The beginning and peak of the disease usually appeared after the milk stage of corn kernels. Therefore, the suitable diseae-reading and disease-sampling times could be arranged according to the milk stage of corn kernels.