玉米褐斑病适宜侵染时期研究

测定玉米褐斑病的适宜侵染时期及不同叶龄玉米叶片浸提液对褐斑病菌休眠孢子囊萌发的影响。结果表明,不同叶龄玉米感染褐斑病的程度不同,5~7叶期玉米较易感病,其中,5叶期玉米上褐斑病发生最重,郑单958和浚单20病情指数分别为51.1和32.5,显著高于其他叶龄。郑单958和浚单20的玉米叶片浸提液均能提高褐斑病菌休眠孢子囊的萌发率,其中,以第5片叶的浸提液对休眠孢子囊的萌发提高最显著,郑单958和浚单20第5片叶的叶片浸提液分别比对照的萌发率提高15.1%和38.8%。因此,5~7叶期玉米易感褐斑病,玉米褐斑病的最适宜侵染时期为5叶期。

Study on Sensitive Infection Stage of Maize Brown Spot Disease

Suitable infection stage and effect of maize leaf extract of different seedling age on the germination of the resting sporangia of Physoderma maydis were tested. The results showed that maize brown spot infection degree varied among different seedling age plants. Five to seven leaf stages were the more susceptible stages to brown spot disease. Among them, five leaf stage was the most susceptible stage with disease index 51.1 and 32.5 on Zhengdan958 and Xundan 20, respectively. Meanwhile, the leaf extract of Zhengdan958 and Xundan 20 could increase the germination of the resting sporangia. Among them, the fifth leaf extract of Zhengdan958 and Xundan 20 significantly increased the germination of the resting sporangia with increasing rate 15.1% and 38.8%, respectively. Therefore, five to seven leaf stage was more susceptible to brown spot disease, with five leaf stage as the most sensitive infection stage.