Abstract Pydiflumetofen is a new fungicide that belongs to the succinate dehydrogenase inhibitor (SDHI) class. This novel fungicide can help protect soybean plants against infection by foliar pathogens, including Cercospora sojina (causal agent of frogeye leaf spot) and Corynespora cassiicola (causal agent of target spot). A total of 88 single-spore isolates of C. sojina collected from soybean fields between 2007 and 2019 from Alabama, Georgia, Illinois, Indiana, Iowa, Kentucky, Louisiana, Michigan, Minnesota, Mississippi, Nebraska, South Dakota, and Tennessee and a total of 76 C. cassiicola single-spore isolates collected from soybean fields in Kentucky between 2017 and 2019 were evaluated for their sensitivity to pydiflumetofen. For this purpose, in vitro bioassays were conducted using different doses of pydiflumetofen (0, 0.001, 0.01, 0.1, 1, and 10 μg/ml). The effective concentrations of pydiflumetofen in which C. sojina and C. cassiicola isolates were inhibited by 50% (EC50) were calculated. The C. sojina EC50 values ranged from 0.335 to 4.335 μg/ml, the mean value was 1.616 μg/ml and median was 1.309 μg/ml. The range, mean and median of C. cassiicola EC50 were 0.037–0.248 μg/ml and 0.086 and 0.069 μg/ml, respectively. Establishing a baseline sensitivity is essential to identify any shifts in sensitivity of fungal populations over time. The findings in this current paper could be used to help monitor the sensitivity of C. sojina and C. cassiicola to pydiflumetofen over time.

中文翻译：

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Cercospora sojina 和 Corynespora cassiicola 对吡氟美芬的基线敏感性

摘要 Pydiflumetofen 是一种新型杀菌剂，属于琥珀酸脱氢酶抑制剂（SDHI）类。这种新型杀菌剂可以帮助保护大豆植物免受叶面病原体的感染，包括 Cercospora sojina（蛙眼叶斑病的病原体）和 Corynespora cassiicola（靶斑病的病原体）。2007 年至 2019 年期间，从阿拉巴马州、佐治亚州、伊利诺伊州、印第安纳州、爱荷华州、肯塔基州、路易斯安那州、密歇根州、明尼苏达州、密西西比州、内布拉斯加州、南达科他州和田纳西州的大豆田中收集了 88 株 C.评估了 2017 年至 2019 年间从肯塔基州大豆田收集的总共 76 株 C. cassiicola 单孢子分离株对吡氟美芬的敏感性。为此，使用不同剂量的吡氟美芬 (0, 0.001, 0.01, 0.1, 1, 和 10 微克/毫升）。计算其中 C. sojina 和 C. cassiicola 分离株被抑制 50% (EC50) 的吡氟美芬的有效浓度。C. sojina EC50 值范围为 0.335 至 4.335 μg/ml，平均值为 1.616 μg/ml，中值为 1.309 μg/ml。C. cassiicola EC50 的范围、平均值和中位数分别为 0.037–0.248 μg/ml 和 0.086 和 0.069 μg/ml。建立基线敏感性对于确定真菌种群敏感性随时间的任何变化至关重要。当前论文中的发现可用于帮助监测 C. sojina 和 C. cassiicola 随着时间的推移对 pydiflumetofen 的敏感性。平均值为 1.616 μg/ml，中值为 1.309 μg/ml。C. cassiicola EC50 的范围、平均值和中位数分别为 0.037–0.248 μg/ml 和 0.086 和 0.069 μg/ml。建立基线敏感性对于确定真菌种群敏感性随时间的任何变化至关重要。当前论文中的发现可用于帮助监测 C. sojina 和 C. cassiicola 随着时间的推移对 pydiflumetofen 的敏感性。平均值为 1.616 μg/ml，中位数为 1.309 μg/ml。C. cassiicola EC50 的范围、平均值和中位数分别为 0.037–0.248 μg/ml 和 0.086 和 0.069 μg/ml。建立基线敏感性对于确定真菌种群敏感性随时间的任何变化至关重要。当前论文中的发现可用于帮助监测 C. sojina 和 C. cassiicola 随着时间的推移对 pydiflumetofen 的敏感性。