Verticillium Psalliotae as a Parasite of Rhopalomyces

SUMMARY

A strain of Rhopalomyces elegans from soil was found to be heavily infected with Verticillium psalliotae which is a serious parasite of the commercial mushroom. Young conidiophores are most vulnerable. Following penetration the Verticillium grows up the conidiophore and enters the conidia which then become filled with the hyphae of the parasite. V. psalliotae was found to attack other members of the Mucorales but not so vigorously. It is suggested that Rhopalomyces and other soil fungi may act as a reservoir for the Verticillium pathogen and thereby have some significance in the etiology of the mushroom disease. V. psalliotae is redescribed.