关键词: 草莓白粉病, 氯氟醚菌唑, 醚菌酯, 生物活性, 田间药效

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．

Key words: strawberry powdery mildew, mefentrifluconazole, kresoxim-methyl, bio-activity, field efficacy