First Report of Cladobotryum varium Causing Cobweb Disease of Pleurotus eryngii var. tuoliensis in China

Pleurotus eryngii var. tuoliensis is a precious edible mushroom, known for its high nutrition and medicinal properties in the world. In June and July 2016, cobweb disease epidemic appeared on fruiting bodies of P. eryngii var. tuoliensis on mushroom farms in Changchun (Jilin Province), China, which made 1% economics loss. Firstly, the surfaces of the fruiting bodies were covered with white, coarse and cobweb-like mycelia. Later, the cap and stipe were rotten. Finally, they were covered with massive of conidia, what can spread rapidly through the air-conditioning systems to disease adjacent ones. Samples were collected and the diseased fruiting bodies were treated by using 0.1% NaClO and sterilized distilled water. They were then placed on two different media, Potato Dextrose Agar (PDA) and Malt-Extract Agar (MEA) supplemented with Kanamycin. Characteristics in culture: Colonies spreading rapidly, reaching 70-80 mm diam at 25 ℃ in 3 d; Cottony, margin regular; White; Aerial mycelium scant, hyphae hyaline, ...