Department of Plant Pathology and Microbiology, University of California, Riverside, Riverside, CA.
Alson H. Smith Jr. Agricultural Research and Extension Center, School of Plant and Environmental Sciences, Virginia Polytechnic Institute and State University, Winchester, VA.
Plant Dis. 2023 Oct;107(10):3164-3175. doi: 10.1094/PDIS-12-22-2947-RE. Epub 2023 Oct 23.
Bitter rot, caused by species, is one of the most devastating summer rot diseases affecting apple production in the Eastern United States. Given the differences in virulence and fungicide sensitivity levels between organisms belonging to the species complex (CASC) and the species complex (CGSC), monitoring their diversity, geographic distribution, and frequency are essential for successful bitter rot management. In a 662-isolate collection from apple orchards in Virginia, isolates from CGSC were dominant (65.5%) in comparison to the CASC (34.5%). In a subsample of 82 representative isolates, using morphological and multilocus phylogenetic analyses, we identified (26.2%), (15.6%), (0.8%), and (0.8%) from CGSC and (22.1%) and (1.6%) from CASC. The dominant species were , followed by and . followed by developed the largest and deepest rot lesions on Honeycrisp fruit in our virulence tests. Detached fruit of nine apple cultivars and one wild accession () were harvested early and late season and tested in controlled conditions for their susceptibility to and . All cultivars were susceptible to both representative bitter rot species, with Honeycrisp fruit being the most susceptible and , accession PI 369855, being the most resistant. We demonstrate that the frequency and prevalence of species in complexes are highly variable in the Mid-Atlantic and provide region-specific data on apple cultivar susceptibility. Our findings are necessary for the successful management of bitter rot as an emerging and persistent problem in apple production both pre- and postharvest.
细菌性果腐病，由 种引起，是影响美国东部苹果生产的最具破坏性的夏季腐烂病之一。鉴于 种复合体（CASC）和 种复合体（CGSC）中各生物体的毒力和杀菌剂敏感性水平存在差异，监测它们的多样性、地理分布和频率对于成功管理细菌性果腐病至关重要。在弗吉尼亚州苹果园的 662 个分离株中，CGSC 的分离株（65.5%）比 CASC（34.5%）更为常见。在 82 个代表性分离株的子样本中，通过形态学和多位点系统发育分析，我们从 CGSC 中鉴定出 （26.2%）、 （15.6%）、 （0.8%）和 （0.8%），从 CASC 中鉴定出 （22.1%）和 （1.6%）。优势种为 ，其次是 和 。在我们的毒力试验中， 继 之后，在 Honeycrisp 果实上形成了最大和最深的腐烂病斑。从九个苹果品种和一个野生品种（）中收获早季和晚季的离体果实，并在受控条件下对其对 和 的敏感性进行测试。所有品种对两种代表性的细菌性果腐病都敏感，其中 Honeycrisp 果实最敏感，PI 369855 品种最具抗性。我们证明了 种在 复合体中的频率和流行度在大西洋中部地区变化很大，并提供了有关苹果品种敏感性的区域特异性数据。我们的研究结果对于成功管理细菌性果腐病作为苹果生产中一个新兴且持久的问题具有重要意义，无论是在采前还是采后。
