First Report That Mucor irregularis Causes White Mold Disease on Substrates Used for Wine-Cap Mushroom (Stropharia rugosoannulata) Cultivation in China

Abstract

Stropharia rugosoannulata is a popular edible mushroom. In October 2020, white mold disease was found on substrates of S. rugosoannulata in a heliogreenhouse in Huai’an city, Jiangsu province, China. The cultivation materials included rice straw (30%), wheat straw (30%), saw dust (30%), and a small amount of wheat bran (5%) and rice bran (5%). In the diseased substrates, a large amount of thick white fungal mycelia was observed with yellow ooze on the surface, which prevented the growth of the mycelia and fruiting bodies of S. rugosoannulata. Disease incidence was calculated as ∼30%. The fungus was identified morphologically and through DNA as Mucor irregularis, and pathogenicity was confirmed. In order to ensure the safe production of S. rugosoannulata, once white mold disease is found, the infected tissue should be removed. This is the first report that M. irregularis causes white mold disease on S. rugosoannulata in China.