oidium

plural oidia

1. A fragile spore produced by some fungi.

   However, in some forms mainly some Hymenomycetes it occurs by the formation of oidia. The oidia are of two main types.

   2004, P.D. Sharma, The Fungi, page 241

   2 more examples

   • Oidia are hyaline, small and thin-walled unicellular sections or fragments of the mycelium. • Oidia may be uni- or binucleate as whether they are produced by the breaking up of the primary or secondary mycelium.

   2003 August, Competition Science Vision, page 802

   Later the pods become covered completely with white powdery mass composed of mycelium, oidiophores and oidia of the fungus.

   2006, A. V. S. S. Sambamurty, A Textbook of Plant Pathology, page 239

2. The fungus Erysiphe necator (= Uncinula necator), which produces powdery mildew in grapes.