The disease is caused by Sclerotinia sclerotiorum. Ink spot causes inky black stains on the outer skin of bulb scales. These are small at first but later cover the entire scale. The fungus moves into bulbs which are blackened on the surface and shrunken and hard on the inside. Destroy diseased bulbs.
Blue mold is a storage disease.
Mosaic causes the bud sheath to be marked by bluish bulbs. This information is for educational purposes only. References to commercial products or trade names does not imply endorsement by MSU Extension or bias against those not mentioned. This information becomes public property upon publication and may be printed verbatim with credit to MSU Extension. Reprinting cannot be used to endorse or advertise a commercial product or company.