YDC (Yeast extract-dextrose-CaCO3) medium is a non-selective media. YDC is used amongst others for subculturing suspected xanthomonads (yellow) and clavibacters (orange) after dilution on semi-selective media (see photo). For detailed information about DuchefaÃâs Phytopathological media have a look at our specialized brochure about this topic. Brochure can be found at the ÃâBrochure sectionÃâ? at the home page of this website.