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Bio-activity Determination and Field Pesticide Effect Evaluation on Composition of Mefentrifluconazole and Kresoxim-methyl against Strawberry Powdery Mildew |
HU Changxiao,CAO Dan*,WANG Haohan,ZHANG Ying |
Xuzhou Vocational College of Bio-engineering,Xuzhou City Key Laboratory of Modern Agro-biotechnology,Xuzhou 221006,Jiangsu,China |
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Abstract In order to clarify the control effect and optimal complex ratio of mefentrifluconazole and kresoxm-methyl on strawberry powdery mildew,this experiment by pot-culture method determined the indoor bio-activity of mefentrifluconazole,kresoxm-methyl single dosages and their composition on strawberry powdery mildew;then based on the optimal synergistic ratio conducted field pesticide effect evaluation.The results showed that the LC50 values of single agents of mefentrifluconazole and kresoxm-methyl against strawberry powdery mildew were 0.416 8 and 2.673 7 mg · L-1,respectively.The mass ratio of the two showed a synergistic effect in the range of 3∶7-6∶4,the synergistic effect was the most significant when compound ratio was 4∶6,the cotoxicity coefficient was 149. Based on this mass ratio,the composition of 400 g·L-1 mefentrifluconazol SC and 50% kresoxm-methyl WC showed the best prevention and control effect at the dosage of 25 g·(667 m2)-1,and field efficacy on strawberry powdery mildew was 78.67%,87.00%,and 91.07%,respectively,7 days after the first,second,and third application.
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Received: 29 November 2022
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