Clavibacter michiganensis

From ISTA Working Sheet #67:

On SCM agar, after 10 days growth, colonies are convex, irregular, mucoid with internal black flecks.

On mSCM agar, after 7 days growth, colonies are light gray, 2-3 mm in diameter, translucent, and easily distinguishable from other mucoid colonies by the presence of internal flecks (specks). As incubation time increases, the colonies become larger and the internal flecks become yellow.

Subculture suspected colonies onto YDC agar, looking for yellow mucoid colonies. Confirm identity with IF staining, ELISA or pathogenicity test.