3种除草剂对七星瓢虫的急性毒性与初级风险评估

Acute toxicity and primary risk assessment of three herbicides to Coccinella septempunctata

为了评估除草剂对七星瓢虫Coccinella septempunctata的毒性影响和初级风险,采用药膜法进行了3种除草剂的急性接触毒性测试,并评估其初级风险。结果表明:10%噁唑酰草胺乳油、10%噁嗪草酮悬浮剂和20%异噁唑草酮悬浮剂对七星瓢虫的急性接触毒性分别为LR_(50)>3.61×10^(2)g a.i./ha,LR_(50)>1.485×10^(2) g a.i./ha,LR_(50)>3.60×10^(2) g a.i./ha。10%噁唑酰草胺乳油、10%噁嗪草酮悬浮剂和20%异噁唑草酮悬浮剂的相对安全系数<5,属于中等及以下风险农药,对七星瓢虫的农田内和农田外喷雾场景风险均可接受(危害商分别为HQ_(in)<0.997,HQ_(in)<2.000,HQ_(in)<1.000,HQ_(in)均<5;HQ_(off)<0.020,HQ_(off)<0.020,HQ_(off)<0.020,HQ_(off)均<5)。综上所述,上述3种除草剂在田间应用时对七星瓢虫安全。

In order to evaluate the toxic effects and risks of herbicides on Coccinella septempunctata,the acute contact toxicity tests of 10%metamifop emulsifiable concentrate(EC),10%oxaziclomefone suspension concentrate(SC)and 20%isoxaflutole suspension concentrate(SC)to C.septempunctata were conducted by tube method.The results showed that toxicity LR_(50) of 10%metamifop emulsifiable concentrate(EC),10%oxaziclomefone suspension concentrate(SC)and 20%isoxaflutole suspension concentrate(SC)to the C.septempunctatas were>3.61×10^(2) g a.i./ha,>1.485×10^(2) g a.i./ha,>3.60×10^(2) g a.i./ha.The relative safety factors of 10%metamifop emulsifiable concentrate(EC),10%oxaziclomefone suspension concentrate(SC)and 20%isoxaflutole suspension concentrate(SC)were less than or equal to 5,which belonged to medium and below-risk pesticides.The risk of 10%metamifop emulsifiable concentrate(EC),10%oxaziclomefone suspension concentrate(SC)and 20%isoxaflutole suspension concentrate(SC)to C.septempunctata were acceptable for in-field and off-field exposure scenario(hazard quotients respectively,HQ_(in)<0.997,HQ_(in)<2.000,HQ_(in)<1.000,HQ_(off)<0.020,HQ_(off)<0.020,HQ_(off)<0.020,all HQ_(in) and HQ_(off)<5).In conclusion,the above three herbicides were safe for C.septempunctata when applied in the field.