Institute of Eco-Environment and Plant Protection, Shanghai Key Laboratory of Protection Horticultural Technology, Shanghai Academy of Agricultural Sciences, Shanghai 201403, China.
Plant Dis. 2023 Sep;107(9):2724-2728. doi: 10.1094/PDIS-10-22-2416-RE. Epub 2023 Sep 20.
Fluxapyroxad, a type of succinate dehydrogenase inhibitor fungicide, has been used to control the growth of gray mold on strawberry for more than 5 years in China. Selection for resistance to the causal agent became a threat to the efficacy of fluxapyroxad. In total, 160 isolates collected from Shanghai during 2020 and 2021 were tested for their resistance to fluxapyroxad using mycelial growth inhibition. The results indicated that the curve of baseline sensitivity was unimodal, with an approximately normal distribution and a mean effective concentration of the fungicide that inhibited growth by 50% (EC) of 0.18 ± 0.01 μg/ml. In total, 27.78 and 48.57% of isolates were resistant to fluxapyroxad in 2020 and 2021, respectively, where the lowest EC value of mycelial growth inhibition was 0.03 μg/ml and the highest value was 51.3 μg/ml. Resistance mechanism analysis showed that the succinate dehydrogenase subunit B () N230I mutation could lead to resistance and P225F mutation could lead to higher resistance. These data suggest that the resistance frequency of isolates to fluxapyroxad increased in 2021 compared with 2020, which requires appropriate fungicide rotation strategies to be implemented in order to control gray mold on strawberry in the future.
氟吡菌酰胺是一种琥珀酸脱氢酶抑制剂类杀菌剂，在中国已用于防治草莓灰霉病 5 年以上。对病原菌的抗性选择已成为氟吡菌酰胺药效的威胁。本研究共采集 2020 年和 2021 年上海地区的 160 个灰霉菌株，采用菌丝生长抑制法测定其对氟吡菌酰胺的抗药性。结果表明，基线敏感曲线呈单峰型，近似正态分布，杀菌剂抑制生长 50%的有效浓度（EC）为 0.18 ± 0.01μg/ml。2020 年和 2021 年分别有 27.78%和 48.57%的菌株对氟吡菌酰胺表现出抗药性，其中最低的菌丝生长抑制 EC 值为 0.03μg/ml，最高值为 51.3μg/ml。抗性机制分析表明，琥珀酸脱氢酶亚基 B（）N230I 突变可导致抗性，P225F 突变可导致更高的抗性。这些数据表明，2021 年与 2020 年相比，菌株对氟吡菌酰胺的抗性频率增加，这需要实施适当的杀菌剂轮作策略，以控制未来草莓灰霉病。
