blue mould

noun

Also called: green mould any fungus of the genus Penicillium that forms a bluish mass on decaying food, leather, etc
any fungal disease of fruit trees characterized by necrosis and a bluish growth on the affected tissue: mostly caused by Penicillium species

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Examples from the Web for blue mould

Historical Examples of blue mould

They kept him in a dark place, like a cheese, until he had the full Tellson flavour and blue-mould upon him.
A Tale of Two Cities
Charles Dickens