Taxonomy, biological characterization and fungicide sensitivity assays of Hypomyces cornea sp. nov. causing cobweb disease on Auricularia cornea

Abstract

Hypomyces spp. is an important group of Hypocreaceae that are widely distributed all over the world, one of the main pathogenic of mushroom cobweb disease. In July 2021, three strains were isolated from symptoms of cobweb disease on fruiting bodies of Auricularia cornea in Guizhou Province, China. Based on phylogenetic analysis and morphological studies, they were then introduced as a new taxon, Hypomyces cornea sp. nov. The pathogenicity test showed that the mushrooms infected with spore suspension had the same symptoms as those in the field, and the same pathogens could be re-isolated, which fulfill Koch’s postulates. The biological characterization of Hypomyces cornea was explored to identify conditions that may be conducive to pathogen habitat, including the effects of different temperature, pH, carbon source, nitrogen source and light conditions. The results showed that the optimal temperature for the pathogen is 25℃, pH = 6, and the best carbon and nitrogen source are soluble starch and peptone, respectively. Nine common fungicides were screened in vitro by hyphal growth inhibition method, and the most suitable fungicide is Prochloraz manganese chloride complex, with high inhibition rate to the pathoge and low inhibition rate to the mushrooms. The results will provide an important basis and material for effective prevention and control of Auricularia cornea cobweb disease.