The ascocarp bears many small, flask-shaped perithecia containing asci. The head is granular because of the ostioles of the embedded perithecia. The perithecia are black, found subepidermaly. Members of this genus typically have superficial, ostiolar perithecia, covered in hairs. Perithecia, another fruiting body, forms after the pycnidia. Shredding of the pith may reveal small, round, black perithecia on the stalks. The primary inocula are the ascospores, sexual spores which are produced in the perithecia. In Ascomycete fungi, locules are chambers within the hymenium in which the perithecia develop. The fungus may appear as a dry, black rot, usually with perithecia and ascospores. This blackened surrounding area is made up of tiny structures called perithecia. The perithecia are ordinally arranged and ovoid. New infections are initiated when spores from the perithecia attach to a compatible insect host. The fungus overwinters as mycelium, sclerotia, and perithecia in infected leaf tissues. During disease, white, fuzzy mycelia with long black perithecia grow out from the lesions (). The perithecia hold a layer of asci which contain the ascospores.