Hu Meng-Jun, Fernández-Ortuño Dolores, Schnabel Guido
Department of Agricultural and Environmental Sciences, Clemson University, Clemson, SC 29634.
Instituto de Hortofruticultura Subtropical y Mediterránea "La Mayora"-Universidad de Málaga-Consejo Superior de Investigaciones Científicas (IHSM-UMA-CSIC), Departamento de Microbiología, Campus de Teatinos, 29071 Málaga, Spain.
Plant Dis. 2016 May;100(5):959-965. doi: 10.1094/PDIS-10-15-1210-RE. Epub 2016 Feb 24.
Succinate dehydrogenase inhibitor (SDHI) fungicides have been used to control gray mold of strawberry for more than a decade, and selection for resistance in the causal agent Botrytis cinerea has become a threat to producers. In total, 2,570 B. cinerea isolates were collected from strawberry fields in the eastern United States across three seasons and their sensitivity to the SDHI materials boscalid, fluopyram, fluxapyroxad, and penthiopyrad was assessed. Assays were based on visual assessment of presence or absence of mycelial growth on media amended with discriminatory fungicide doses to distinguish sensitive from resistant isolates, respectively. Overall frequencies of isolates resistant to boscalid, fluopyram, fluxapyroxad, and penthiopyrad increased over the 3 years to 30.0, 1.0, 5.5, and 7.4%, respectively. Four resistance patterns, designated A, B, C, or D, were found. Pattern A isolates were resistant to boscalid with the allele H272R at locus sdhB; pattern B isolates were resistant to boscalid and penthiopyrad with the allele H272R or H272Y at locus sdhB; pattern C isolates were resistant to boscalid, fluxapyroxad, and penthiopyrad with the allele H272Y at locus sdhB; and pattern D isolates were resistant to boscalid, fluopyram, fluxapyroxad, and penthiopyrad with alleles P225F or N230I at locus sdhB. Isolates with alleles H272Y, N230I, or P225F were sensitive to a new SDHI, benzovindiflupyr, with mean effective dose that inhibits 50% of mycelial growth values of less than 0.5 μg/ml for each genotype, suggesting that this fungicide may be useful for resistance management. Our data show an increase of B. cinerea isolates resistant to SDHI fungicides over three consecutive production seasons. Resistance management practices must be implemented for the sustained efficacy of SDHI fungicides against gray mold of strawberry.
琥珀酸脱氢酶抑制剂（SDHI）类杀菌剂已用于防治草莓灰霉病十余年，病原菌灰葡萄孢中抗药性的产生已对种植者构成威胁。在美国东部，分三个季节从草莓田收集了总共2570株灰葡萄孢分离株，并评估了它们对SDHI类药剂啶酰菌胺、氟吡菌酰胺、氟唑菌酰胺和戊唑嘧菌胺的敏感性。检测基于视觉评估在添加了区分性杀菌剂剂量的培养基上是否有菌丝生长，以分别区分敏感和抗性分离株。在这3年中，对啶酰菌胺、氟吡菌酰胺、氟唑菌酰胺和戊唑嘧菌胺产生抗性的分离株总体频率分别上升至30.0%、1.0%、5.5%和7.4%。发现了四种抗性模式，分别命名为A、B、C或D。模式A分离株对啶酰菌胺具有抗性，在sdhB位点有等位基因H272R；模式B分离株对啶酰菌胺和戊唑嘧菌胺具有抗性，在sdhB位点有等位基因H272R或H272Y；模式C分离株对啶酰菌胺、氟唑菌酰胺和戊唑嘧菌胺具有抗性，在sdhB位点有等位基因H272Y；模式D分离株对啶酰菌胺、氟吡菌酰胺、氟唑菌酰胺和戊唑嘧菌胺具有抗性，在sdhB位点有等位基因P225F或N230I。具有等位基因H272Y、N230I或P225F的分离株对一种新型SDHI类药剂苯并烯氟菌唑敏感，每种基因型抑制50%菌丝生长的平均有效剂量值小于0.5μg/ml，这表明该杀菌剂可能有助于抗性治理。我们的数据显示，在连续三个生产季节中，对SDHI类杀菌剂产生抗性的灰葡萄孢分离株有所增加。必须实施抗性治理措施，以确保SDHI类杀菌剂对草莓灰霉病持续有效。
