醚菊酯、噻虫嗪及其混配对贵州三地褐飞虱的毒力及田间防治效果

Toxicity of ethofenprox,thiamethoxam and their mixtures on Nilaparvata lugens and the field control effect in Guizhou province

为了进一步了解醚菊酯、噻虫嗪及其混合液对贵州3地(桐梓、黄平、开阳)褐飞虱3龄若虫的毒力,为开发防治褐飞虱的复配药剂提供科学依据,本研究选择噻虫嗪和醚菊酯2种单剂及其混合液,采用稻茎浸渍法对褐飞虱进行室内毒力测定,并采用田间喷雾法在贵州黄平地区进行了田间防效试验。结果表明,醚菊酯、噻虫嗪及其混合液对贵州3地褐飞虱的LC_(50)平均值分别为18.741 1μg/ml、1.407 6μg/ml和1.254 5μg/ml。与敏感品系相比,贵州3地褐飞虱对噻虫嗪的抗性表现为中等水平,而对醚菊酯的抗性表现为敏感水平。噻虫嗪和醚菊酯以1∶7的比例混配施用7 d后的平均防效为82.38%,而醚菊酯和噻虫嗪单剂施用7 d后的平均防效分别为69.64%和71.88%。噻虫嗪和醚菊酯按有效成分1∶7混合时,混合药剂的防效明显高于醚菊酯和噻虫嗪单剂的防效,生产上进行褐飞虱防治时,可首选该混配配方。

The present experiment was conducted to study the toxic effects of ethofenprox,thiamethoxam and their mixtures on the 3rd nymph of Nilaparvata lugens which were collected from Huangping,Kaiyang and Tongzi county,Guizhou province and to provide scientific basis for developing chemical pesticide for its control. The toxic effects of ethofenprox,thiamethoxam and their mixtures on the 3rd nymph of Nilaparvata lugens were determined by using rice stem dipping method and the field control effect was conducted at Huangping,Guizhou province. The results showed that the LC50 values of ethofenprox,thiamethoxam and their mixtures to Nilaparvata lugens were 18. 741 1 μg / ml,1. 407 6 μg / ml and 1. 254 5 μg / ml,respectively. Compared with the susceptible strain of Nilaparvata lugens,the populations developed moderate level of resistance to thiamethoxam and were sensitive to ethofenprox. The efficacy of the mixtures of thiamethoxam and ethofenprox（ 1 ∶ 7） was 82. 38%,and the efficacies of ethofenprox and thiamethoxam were 69. 64% and 71. 88% on the7 th day after spraying,respectively. The mixtures of thiamethoxam and ethofenprox（ 1 ∶ 7） had better control effects on Nilaparvata lugens than single does. During prevention planthopper,the mixed formulation may be preferred for using.