First Report of Gray Mold Caused byBotrytis cinereaon Strawflower in Korea

Abstract

Strawflower (Xerochrysum bracteatum) is a flowering plant of the Asteraceae. In July 2016, approximately 10% of inflorescences were observed displaying gray mold symptoms in a private garden in Gangneung, Korea. Initial infection started from the base of inflorescence and gradually moved to the flower spike where it finally collapsed. Lesions expanded rapidly under cool, humid conditions. Diseased tissue was excised and surface sterilized by immersing in 1% sodium hypochlorite (NaOCl) for 1 min, rinsed three times with sterilized distilled water, placed on potato dextrose agar (PDA, Difco) plates, and incubated at 20 ± 2°C for 7 days. The fungus produced gray to grayish brown colonies that sporulated abundantly. The conidia (n = 50) were one-celled, ellipsoid or ovoid, dark brown, and 5.1 to 7.2 × 5.3 to 5.6 μm in vivo, and 5.1 to 10.4 × 5.1 to 7.8 μm in vitro. Conidiophores (n = 20) arose solitary or in groups, straight or flexuous, septate, with an inflated basal cell brown to light brown, and measured ...