The process in which oidia, a type of asexual spore found in fungi, are formed. Oidia are borne a few at a time on very simple hyphae that protrude a short distance into the substrate, and are usually presumed not to constitute the main reproductive strategy of the fungus.
Source:
GOC:mah,
http://www.ilmyco.gen.chicago.il.us/Terms/oidiu163.html