First Report of Bitter Rot Caused by Colletotrichum acutatum on Apple in China

作者：R. Zhang, S. F. Wang, Jian Cui, Guangzheng Sun, Mark L. Gleason · 发表于：Plant Disease · 年份：2008 · DOI：10.1094/pdis-92-10-1474b · 被引用次数：12 · 研究领域：Plant Pathogens and Fungal Diseases、Postharvest Quality and Shelf Life Management、Yeasts and Rust Fungi Studies

Bitter rot of apple caused by Colletotrichum gloeosporioides was first reported in China in 1985 (3). In China, apples are grown on approximately 2 million ha, and bitter rot occurs in almost all production areas, with crop damage ranging from 30 to 70%. During the summer of 2007, fungi were isolated from apple fruit exhibiting bitter rot symptoms in 12 and 9 orchards in Shaanxi and Henan provinces, respectively, in China. Symptoms included 2- to 3-cm-diameter, sunken, brown lesions on the fruit surface that contained black, pinhead-size fruiting structures producing orange conidial masses under high humidity, similar to that of C. gloeosporioides. On potato dextrose agar (PDA), colonies were white, pale gray, or pale orange when grown at 25°C. Conidia were 8 to 16 × 2.5 to 4 μm, fusiform, pointed at one or both ends, one celled, thin walled, aseptate, and hyaline. Appressoria were 6.5 to 11 × 4.5 to 7.5 μm, clavate to circular, and light to dark brown. These characteristics matched published descriptions of C. acutatum (2). To confirm pathogenicity, three mature, healthy apples (cv. Fuji) were surface disinfested with 70% ethanol and then wounded with a sterile needle. After being inoculated with a spore suspension (1 × 10 5 conidia/ml) prepared from a 2-week-old culture on PDA, these apples were sealed in a plastic bag and incubated at 25°C. Symptoms appeared 3 to 5 days after inoculation and began to enlarge 7 days later, forming lesions with fruiting structures. Under hig...