Problem Identifier Unit Screen//v.w/ RR Template

Problem Identifier Unit Screen//v.w/ RR Template Penicillium Corm Rot

Problem
Corky, reddish brown, sunken lesions ½ inch or larger in diameter appear on the corm (the "bulb" of the gladiolus plant). In cool, moist conditions, the rotted areas of the corm become covered with a blue-green mold. Infected corms that have been planted may not produce any foliage. Foliage that is produced turns yellow and wilts. The corms are rotted and moldy.

Analysis
This disease is caused by a common fungus (Penicillium gladioli) that is most often noticed on corms in storage. The fungus infects the corm through wounds or abrasions that usually occur when the corm is dug out of the ground to be put into storage. After the initial infection, the rot spreads throughout the corm and up into the stem tissue. The corms rot rapidly when they are stored in warm, humid conditions. The fungus forms masses of blue-green spores and tiny brown fungal pellets that can survive dry conditions and extremes of temperatures to invade healthy corms. If mildly infected corms are planted, they may or may not produce foliage, depending upon how severely their infection has progressed. Eventually, any foliage produced will turn yellow and die.

Solution
Dig up corms carefully only when the gladiolus leaves have turned entirely yellow in the fall. Dry them immediately. Destroy all corms showing decay. Handle healthy-looking corms carefully to prevent injuries. Dip them in a fungicide solution containing captan before storing and again before planting them. Store corms in a dry, cool (40° to 45°F) location.

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