The control efficiency as affected by pesticide volumes (PV) , spraying approaches (fine spray, coarse spray) to the major pests and diseases on rice plants at late growing stage were evaluated. For the rice neck blast, rice spikelet rot disease and leaf folder occurred at upper parts of rice plants, the best control efficiencies were obtained by two times of fine sprays(TFS), and the worst by two times of coarse sprays(TCS) at the same pesticide application level and PV for a given rice variety. The control efficiencies by the first fine spray and then coarse spray (FFSCS) or the first coarse spray and then fine spray(FCSFS) showed no significant difference. The control efficiency to japonica Xiushui 09 was better than that of the indica/japonica hybrid combination Yongyou 12. For a rice variety at the same pesticide application level, the best control efficiency was obtained at PVs of 675 or 750 L/hm2 , followed by 900, 1200, 450 L/ hm2 and 225 L/hm2. For a variety at a given PVs, the best control efficiencies to sheath blight and planthoppers occurred on the middle and lower parts of rice plants, were gained by TCS, followed by FCSFS, FFSCS, and TFS. Control efficiency for Xiushui 09 was better than that for Yongyou 12 at a given PV and by the same approach. For a variety by the same spraying means, the best control efficiency was obtained at the PV of 900 L/hm2 , followed by 1200 and 750 L/hm2. The less water and the worse control efficiency when the PV was less than 900 L/hm2. The control efficiencies to sheath blight and planthoppers were less than 50% at the PV of 225 L/hm2. And by TFS, especially for Yongyou 12. At the same pesticide application level, the control efficiency didn't increase with the rising PV.%设计不同药液量、喷雾方法(细雾、粗雾)防治水稻后期发生的重要病虫害.结果表明,在药剂有效成分用量相同时,对于发生在稻株上部的穗颈瘟、穗腐病和稻纵卷叶螟,同一品种和相同药液量下,细雾喷雾防效最好,粗雾喷雾防效最差；第1次喷细雾第2次喷粗雾,或第1次喷粗雾第2次细雾防效相当.同一品种相同喷雾方法,以用药量675L/hm2或750L/hm2防效最好,其次是900L/hm2、1200L/hm2和450L/hm2,最差的是225L/hm2.对于发生在稻株中下部的纹枯病和稻飞虱,同一品种相同药液量时,2次粗雾喷雾防效最好,其次是第1次喷细雾第2次喷粗雾,再次是第1次喷粗雾第2次喷细雾,2次细雾喷雾防效最差.无论是发生在上部的病虫害,还是发生在中下部的病虫害,药液量和喷雾方法相同,对秀水09的防效均好于对甬优12.同一品种相同喷雾方法,以900L/hm2药液量防效最好,其次是1200L/hm2和750L/hm2,药液量少于900L/hm2时,防效随药液量减少而下降.225L/hm2药液量且采用细雾喷雾,对纹枯病和稻飞虱的防效均低于50％,特别是对甬优12的防效更差.但在有效成分相同的情况下,并非药液量越多防效就越好.
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