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

摘要： 为明确氯氟醚菌唑与醚菌酯对草莓白粉病的防治效果及最佳复配比，采用盆栽法测定了氯氟醚菌唑、醚菌酯单剂及二者组合物对草莓白粉病的室内生物活性，并基于最佳增效配比进行了田间药效评价试验。结果表明，氯氟醚菌唑、醚菌酯单剂对草莓白粉病的LC50值分别为0.416 8、2.673 7 mg·L-1，二者质量比在3∶7～6∶4范围内呈现增效作用，以4∶6复配时增效最显著，共毒系数为149。基于该质量比的400 g·L-1 氯氟醚菌唑悬浮剂（SC）与50% 醚菌酯水分散粒剂（WG）组合物，在用药量25 g·（667 m2）-1 时防效最佳，第1、2、3 次施药后7 d 对草莓白粉病的田间防效分别为78.67%、87.00%、91.07%。

关键词: 草莓白粉病, 氯氟醚菌唑, 醚菌酯, 生物活性, 田间药效