阿维菌素和毒死蜱对玉米象和赤拟谷盗的毒力测定

用3种低毒农药对生活在稻谷中的玉米象和赤拟谷盗2种储粮害虫用喷雾法进行室内毒力测定。结果表明：（1）1.8%阿维菌素乳油(EC)、2%阿维菌素微囊悬浮剂、48%毒死蜱乳油(EC)对玉米象的致死中剂量（LD50）分别为0.01mg／kg、0.07mg／kg、4.65mg／kg，而对赤拟谷盗的LD50分别为0.08mg／kg、0.50mg／kg、5.89mg／kg；（2）在相同剂量下，3种药剂中以1.8%阿维菌素EC对2种害虫的毒杀速度最快；（3）玉米象比赤拟谷盗对这3种药剂更敏感。建议采用1.8%阿维菌素EC、2%阿维菌素微囊悬浮剂、48%毒死蜱EC防治玉米象的使用剂量分别为0.05mg／kg、0.80mg／kg和2.0mg／kg，而防治赤拟谷盗则分别为0.05mg／kg、0.80mg／kg和8.0mg／kg。

Toxicities of Avermectins and Chlorpyrifos to Sitophilus zeamais Motschulsky and Tribolium castaneum (Herbst)

Virulence of avermectins 1.8% EC,2% microcapsule suspension and chlorpyrifos 48% EC to S.zeamais and T.castaneum that lived in paddy ware tested by means of spraying in the laboratory.The results showed as follows:(1)The LD50s of avermectin 1.8% EC,2% microcapsule suspension and chlorpyrifos 48% EC to S.zeamais were respectively 0.01mg/kg,0.07mg/kg and 4.65mg/kg,and those of them to T.castaneum were respectively 0.08mg/kg,0.50mg/kg and 5.89mg/kg.(2)The death rate of avermectin 1.8% EC to the two stored-grain insect pests was the highest among three kinds of insecticides in the same conditions.(3)S.zeamais was more sensitive to the three kinds of insecticides than T.castaneum.The recommended dosages of Avermectin 1.8% EC,2% microcapsule suspension and Chlorprifos 48% EC are respectively 0.05mg/kg,0.80mg/kg and 2.0mg/kg in order to control S.zeamais,and those of the three insecticides are respectively 0.05mg/kg,0.80mg/kg and 8.0mg/kg in order to control T.castaneum.