6种杀虫剂对水稻褐飞虱田间种群的毒力及控制作用

2009～2010年,采用稻秆浸渍接虫法,测定了福建省3个地区的褐飞虱田间种群对6种杀虫剂的敏感性并进行抗性分析,在仙游县晚稻田褐飞虱初孵若虫始盛期,采用喷雾法对6种药剂的田间控制作用进行了研究,结果表明:同一个种群的褐飞虱若虫对同一种药剂的敏感性随着虫龄的增加而降低；烯啶虫胺对不同地理种群的褐飞虱若虫均表现出最高的毒...

Toxicity and Efficacy of Six Insecticides on Field Population of Nilaparvata lugens (St(a)l)

The stem-dipping of rice stalks was used to determine the susceptibility of Nilaparvata lugens(Stl) to 6 insecticides.Different field populations collected from 3 regions in Fujian from 2009 to 2010 were used for the study.The experiment was conducted by spraying the insecticides during the beginning of the peak N.lugens nymph-hatching in the late-rice growing field at Xianyou County.The results showed that the susceptibility of N.lugens nymphs to insecticides decreased with the insect′s age.The toxicity of nitenpyram to N.lugens was the highest among the 6 insecticides.The LC50 on the 2nd,3rd and 4-5th instar nyphms of N.lugens populations were 0.941 7-1.016 7 mg·L-1,1.187 2-1.341 0 mg·L-1 and 1.610 2-1.937 0 mg·L-1,respectively.Isoprocarb exhibited the lowest toxicity among all insecticides tested,with LC50 on 2nd,3rd and 4-5th instar nyphms of 37.118 3-46.733 5 mg·L-1,45.924 1-56.950 4 mg·L-1 and 50.993 8-70.191 2 mg·L-1,respectively.The insecticide resistance to imidacloprid of the N.lugens population in Fuzhou was considered high,and the population in Longhai and Xianyou extremely high;and,that of all 3 N.lugens populations moderate to thiamethoxam,buprofezin and isoprocarb.All 3 populations were susceptible to nitenpyram.Among the 6 insecticides,nitenpyram and isoprocarb exhibited a control effect on the field populations of N.lugens more rapidly than the others.But,the control effect of nitenpyram and pymetrozine lasted longer than that of the others.In the beginning of the peak N.lugens nymph-hatching,imidacloprid was effective with a dosage of 30-45 g(a.i.) hm-2.In recent years,the serious insecticide resistance and the declined efficacy of imidacloprid,long-term applications to control N.lugens with large dose have become inappropriate and inpractical.Alternative strategies,such as alternating and rotating the use of different insecticides,need to be explored.It was postulated that nitenpyram and/or pymetrozine could be the candidates as replacements for imidacloprid.