Department of Plant Pathology, North Dakota State University, Fargo, ND 58108.
Plant Dis. 2021 Oct;105(10):3015-3024. doi: 10.1094/PDIS-12-20-2718-RE. Epub 2021 Nov 5.
Early blight, caused by , is observed annually in all midwestern potato production areas. The use of foliar fungicides remains a primary management strategy. However, has developed reduced sensitivity or resistance to many single-site fungicides such as quinone outside inhibitor (QoI, FRAC group 11), succinate dehydrogenase inhibitor (SDHI, FRAC group 7), demethylation inhibitor (DMI, FRAC group 3), and anilinopyrimidine (AP, FRAC group 9) fungicides. Boscalid, fluopyram, solatenol, and adepidyn are EPA-registered SDHI fungicides used commercially on a variety of crops, including potato. Five SDH mutations have been characterized previously in that affect the efficacy of boscalid while only one of these mutations has been demonstrated to negatively affect fluopyram efficacy. Conidial germination assays were used to determine if a shift in sensitivity has occurred in these SDHI fungicides. isolates collected prior to the commercial application of SDHI fungicides (baseline) were compared with recently collected isolates (nonbaseline). Greenhouse evaluations were conducted also to evaluate the efficacy of boscalid, fluopyram, solatenol, and adepidyn on isolates possessing individual SDH mutations. Additionally, field trials were conducted to determine the effects of application of these SDHI fungicides on the frequency of SDH mutations. Fluopyram, solatenol, and adepidyn had high intrinsic activity against when compared with boscalid, based on in vitro assays. The application of adepidyn and solatenol resulted in greater early blight control than the application of boscalid and fluopyram in greenhouse experiments. Molecular characterization of isolates collected from the field trials determined that the frequency of the H134R-mutation can increase in response to more recently developed SDHI fungicides. In contrast, the H278R/Y- and H133R-mutations decreased to the point of being nearly absent in these field experiments.
早疫病由引起，在中西部所有马铃薯产区每年都有发生。使用叶面杀菌剂仍然是主要的管理策略。然而，已经对许多单作用杀菌剂（如醌外抑制剂（QoI，FRAC 组 11）、琥珀酸脱氢酶抑制剂（SDHI，FRAC 组 7）、脱甲基抑制剂（DMI，FRAC 组 3）和苯胺嘧啶（AP，FRAC 组 9））产生了降低的敏感性或抗性。啶氧菌酯、氟吡菌酰胺、咯菌腈和噻呋酰胺是 EPA 注册的 SDHI 杀菌剂，在包括马铃薯在内的多种作物上商业使用。以前已经鉴定出 中的五个 SDH 突变，这些突变影响啶氧菌酯的功效，而只有一个突变被证明会对氟吡菌酰胺的功效产生负面影响。通过分生孢子萌发试验来确定这些 SDHI 杀菌剂的敏感性是否发生了变化。与基线时期（商业应用 SDHI 杀菌剂之前采集的）相比，比较了最近采集的（非基线）分离株。还进行了温室评估，以评估啶氧菌酯、氟吡菌酰胺、咯菌腈和噻呋酰胺对具有单个 SDH 突变的分离株的功效。此外，还进行了田间试验，以确定这些 SDHI 杀菌剂的施用对 SDH 突变频率的影响。与啶氧菌酯相比，氟吡菌酰胺、咯菌腈和噻呋酰胺对具有较高的内在活性，这基于体外试验。在温室试验中，与啶氧菌酯和氟吡菌酰胺相比，施用噻呋酰胺和咯菌腈可更好地控制早疫病。从田间试验中采集的分离株的分子特征确定，H134R 突变的频率可以增加，以响应最近开发的 SDHI 杀菌剂。相比之下，在这些田间试验中，H278R/Y-和 H133R 突变减少到几乎不存在的程度。
