Acute toxicity and risk assessment of 5 multiple combined herbicides to Trichogramma dendrolimi and Coccinella septempunctata
[Aims]To evaluate the acute toxicity and risk of 5 multiple combined herbicides,including pretilachlor· halosulfuron-methyl 38％OD,flucarbazone-sodium·isoproturon 35％OD,florasulam·glyphosate 42％OD,diflufenican·pinoxaden·isoproturon 75％WG,clopyralid·picloram·benazolin-ethyl 35％SC,the acute toxicity of the herbicides to Trichogramma dendrolimi and Coccinella septempunctata were tested.[Methods]The acute toxicity of natural enemy insects was studied by the finger-tube drug-membrane method,and the primary risk assessment was evaluated by safety factor.[Results]The 24 h-LR50 of the 5 herbicides on T.dendrolimi were 6.317× 10-3,5.283 × 103,1.269× 10-2,＞9.000× 10-2 and＞2.625× 10-2 mg a.i./cm2,respectively.The safety factors of the first three herbicides were 1.03,0.73 and 0.93,which were moderate risk,and the safety factors of the last two herbicides were＞10,which were low risk.The LR50 of the first two herbicides on C.septempunctata were 1.684× 10-2 and 1.557× 10-2 mg a.i./cm2,respectively,the safety factors were 2.75 and 2.11,which were moderate risk;the LR50 of the last three herbicides on C.septempunctata were greater than 6.817× 10-2,4.500× 10-2 and 1.313× 10-2 mg a.i./cm2,respectively,with safety factors greater than 5,which are low risk.[Conclusions]Pretilachlor·halosulfuron-methyl 38％OD,flucarbazone-sodium·isoproturon 35％OD,florasulam·glyphosate 42％OD have certain risks to the natural enemy insects T.dendrolimi and C.septempunctata,so an interval is recommended between releasing Trichogramma and applying the herbicides,and avoid using them during the breeding period of natural enemy insects.
万方数据
维普
