Studies On The Mixed Formulations Of Imidacloprid And Deltamethrin

In this study, the toxicity of the mixture of imidacloprid and deltamethrin against cotton aphid(Aphis gossypii Glover) and vegetable aphid (Lipaphis erysimi (Kaltenbach)) was tested in the laboratory tlirough leaf rapid-dip method, topical application method, pesticide residue method and spraying method. After the test of toxicity, the joint action of imidacloprid and deltamethrin was evaluated by the co-toxicity coefficient(CTC) which was calculated by the method of Mansour, the method of Sun and the method of Finney. According to the optimal mixture ratio, two mixed formulations were compounded successfully. The mixed formulations of optimal mixture ratio were also tested in pot trials and in field trials. All the result of laboratory and field showed that.The optimal mixture ratio of the mixture of imidacloprid and deltamethrin against cotton aphid (Aphis gossypii Glover) was the ratio of 3:l(imidacloprid: deltamethrin) .The co-toxicity coefficient (CTC) in the result which was counted through the method of Sun was above 100 which indicated a remarkable synergism. Taking the ratio of 3:1 (imidacloprid : deltamethrin) as the optimal mixture ratio, imidacloprid deltamcthrin 5% (3:1) mixed emulsifiable concentrate (imidacloprid deltamethrin 5% EC(3:1)) was made up successfully in the laboratory, at the same time,the heat stability, the cold stability, the emulsion stability on standing ,the emulsifying power, the content of water and the pH of imidacloprid 昫eltamethrin 5% EC(3:1) were determined. The pot trials and the field experiments were conducted to examine the joint action of the mixture of imidacloprid and deltamethrin,the result showed that imidacloprid ?deltamethrin 5% EC(3:1) at 0.5-1.0g a.i./667m2 against cotton aphid gained good control effect. Applied at 1.0g a.i./667m2,the percentage of the control effect against cotton aphid was 97% in 1 day, 100% in 7 days and the persistant effect reached more than 21 days.In the laboratory bioassay and synergistic effect of the mixture of imidacloprid and deltamethrin against vegetable aphid (Lipaphis erysimi (Kaltenbach)) ,the optimal mixture ratio was the ratio of 4:1 (imidacloprid: deltamethrin) . Its co-toxicity coefficient(CTC) in the result which was counted through the method of Sun was above 100 which indicated a remarkable synergism. Taking the ratio of 4:l(imidacloprid : deltamethrin) as the optimal mixture ratio, imidacloprid deltamethrin 5% EC(4:1) was made up successfully hi the laboratory, at the same time ,the heat stability, the cold stability, the emulsion stability on standing ,the emulsifying power, the content of water and the pH of imidacloprid deltamethrin 5% EC(4:1) were determined by different methods. The pot trials and the field experiments were conducted to examine the joint action of imidacloprid deltamethrin 5% EC(4:l),the result showed that imidacloprid deltamethrin 5% EC(4:1) was very effective to control vegetable aphids in rape field, applied at 1.0g a.i./667m2,the percentage of the control effect against vegetable aphid was above 85% in 1 day, 100% in 7 days and the persistant effect remained 80% after the treament of 21 days.