关键词: 水稻白叶枯病, 危害损失, 防治指标

Abstract:

Rice bacterial leaf blight （BLB） is one of the most common epidemic rice disease in Zhejiang Province. Investigating the yield losses and scientifically making control threshold are important for effective forecast and integrated control of the disease, and also have great significance to ensure the rice harvest and farmers’ higher income. In this study, through investigation of the occurrence, damage and yield losses caused by BLB in Tonglu and Yuhang in these years, the authors built six yield loss models based on independent variables of rice plants morbidity or rice leaves morbidity respectively, in tillering, jointing and booting stage, to show the relationship between BLB occurrence and yield losses. By the investigation on the main economic influence from BLB infection, the authors found that infected plants had lower height, fewer filled grains and higher blighted rate, which mainly caused the yield loss. On the basis of tested field pesticide costs and economic threshold, the authors first proposed the threshold value of control as 5% rice plants morbidity and 3% rice leaves morbidity. After field verification and application in Tonglu, Whenling and Wenzhou, et al, the control threshold was proved to be consistent with the actual situation, which reduced pesticides using area by one third, decreased pesticide consumption, controlled the costs, improved efficiency, and eventually acquired rather remarkable economic, social and ecological benefits.

Key words: rice bacterial leaf blight, yield loss, control threshold