宁虫素对水稻螟虫的毒力及防治效果

TOXICITIES AND CONTROL EFFECT OF NINGCHONGSU AGAINST RICE STEM BORERS

研究了宁虫素对水稻螟虫的毒力及防治效果。结果表明 ,宁虫素对水稻纵卷叶螟、二化螟、三化螟具有较高的毒力 ,其LC50 分别为 3 .75mg/kg、2 .0 2mg/kg和 0 .0 8mg/kg ,该药对水稻螟虫具有明显的增效作用。其中 ,对二化螟、三化螟、纵卷叶螟的共毒系数分别为 2 0 6.17,178.61和 185.14。田间试验结果表明 ,宁虫素对稻纵卷叶螟、二化螟具有良好的控制效应及保穗效果 ,单位面积 ( 666.7m2 )用 3 0 g、2 0g、10 g宁虫素对稻纵卷叶螟药后 7d的防效分别为 98.0 7%、91.15%、80 .2 6% ,14d的防效分别为 10 0 .0 %、99.3 5%、93 .3 4 % ;用 2 5g宁虫素对二化螟田间防效为 86.8% ,保穗效果为 88.8%。

Toxicities and control effects of Ningchongsu against rice stem borers were tested.The results show that Ningchongsu is highly toxic to Cnaphalocrocis medinalis Guenee, Chilo suppressalis Walker and Tryporyza incertulas Walker among tested pesticides.Its LC 50 are 3.75 ,2.02,and 0.08 mg/kg, respectively.Ningchongsu had also apparent synergism in controlling these pests,the co toxicity coefficients are 178.61,206.17 and 185.14,respectively.The results of field trial show applications of 30,20,10g/666.7m 2 Ningchongsu all have good control effect in roller killing rate in treatments against C.medinalis ,the roller killing rates are 98.07%, 91.15%,80.26%,respectively,7d after application,and 100.0%, 99.35%,93.34%,respectively,14d after application;application of 25g/666.7m 2 Ningchongsu has good control effects in borer killing and ear retention rates in treatment against C.suppressalis ,the borer killing rate is 86.8% and ear retention rate is 88.8%.