【摘要】 为了评价黄瓜白粉病菌对己唑醇的抗性风险,采用子叶法测定了山东地区50个黄瓜白粉病菌菌株对己唑醇的敏感性。结果表明,各菌株敏感性存在较大差异,EC50值最低为0.0017μg/mL,最高达0.16μg/mL,平均值为0.028μg/mL,由于所有菌株均采自未使用过脱甲基抑制剂类杀菌剂的黄瓜日光温室,敏感性频率呈近似正态分布,可作为黄瓜白粉病菌对己唑醇的相对敏感基线。以野生菌株为材料,以紫外线诱导和药剂驯化相结合获得了2个黄瓜白粉病菌对己唑醇的抗性菌株,比较了抗性菌株和敏感菌株的适合度和分生孢子的竞争能力。结果表明,无药情况下2个抗性菌株与野生菌株适合度无显著差异。抗性菌株和敏感菌株分生孢子以80∶20混合培养7代后,抗性菌株的频率变化不明显;50∶50混合培养7代,中抗菌株的抗性频率明显降低,而高抗菌株的抗性频率降低不明显;20∶80混合培养7代,抗性菌株的频率变低甚至消失。更多还原

【Abstract】 In order to evaluate the resistant risk of the pathogen of powdery mildew on cucumber to hexaconazole,the sensitivity of Sphaerotheca fuliginea of 50 strains collected from Shandong Province,China to hexaconazole was measured on cucumber seedling cotyledons.The results showed that the EC50 values of strains varied from 0.0017 μg/mL to 0.16 μg/mL with the mean of 0.028 μg/mL,which could be regarded as the baseline sensitivity of S.fuliginea to hexaconazole because the 50 strains were collected from the greenhouse where no demethylation inhibitor group of fungicides were applied,and frequencies distribution of the 50 strains was similar with Gaussian distribution.Two hexaconazole-resistant strains were obtained by UV irradiation and hexaconazole screening in the laboratory,and then the fitness parameters and competition ability of resistant and sensitive strains were measured.The results showed that fitness of resistant strains and sensitive strains had no significant difference in absence of fungicide.No significant difference occurred in ratio of resistant strains to sensitive strains when conidia of resistant and sensitive strains were mixed at the ratio of 80 ∶20 and incubated for 7 generations in absence of fungicide;when mixed with 50 ∶50,the ratio of moderately resistant strain decreased significantly,meanwhile the ratio of high resistant strain didn’t change significantly;when mixed with 20∶80,the ratio of resistant strain decreased.更多还原