Occurrence of Itersonilia and Tilletiopsis on lesions caused by Entyloma

Abstract

Itersonilia perplexans is prevalent on lesions caused by species of Entyloma and by other plant pathogenic fungi and is occasionally present on ‘healthy’ leaves. Tilletiopsis washingtonensis and T. minor are present on most leaves whether or not attacked by Entyloma. Chlamydospores of E. calendulae and E. dahliae germinate in the host forming needle-shaped and allantoid sporidia ; the latter superficially resemble the balli-stospores of T. washingtonensis but are distinguishable from them when they germinate. Inoculations demonstrated that symptoms characteristic of infection by Entyloma are produced by the needle-shaped sporidia; no connexion was established between the life cycles of Entyloma and either I. perplexans or T. washingtonensis.