Rhizomorph Production by Armillaria mellea Induced by Ethanol and Related Compounds.

Armillaria mellea produced abundant rhizomorphs when grown on a chemically defined medium containing ethanol at concentrations as low as 50 parts per million. In the absence of ethanol no rhizomorphs were formed. Rhizomorph production was also stimulated by I-propanol, isopropanol, and 1-butanol as well as by acetaldehyde (to a lesser extent). Potassium acetate had very slight stimulating effect, and methanol was completely ineffective.