Cleistothecia of Podosphaera leucotricha (Ell. et Ev.) Salm. occur annually in Czechoslovakia as early as mid-June. Ascospore differentiation is influenced by weather. Some differentiation continues after overwintering, but ascospores were not found to germinate.
Molnár J. (1971): Cleistothecia of the fungus Podosphaera leucotricha (Ell. et Ev.) Salm. under the conditions of Czechoslovakia. – Česká Mykologie 25(4): 211–218.