Scouting for diseases: Sclerotinia
May 18, 2007 - Author: Jan Byrne, MSU Diagnostic Services, Department of Plant Pathology
Editor’s note: This article is from the archives of the MSU Crop Advisory Team
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Pathogen: Sclerotinia sclerotiorum (View images).
Hosts Include: Anemone, Aquilegia, Aster, Bellis, Campanula, Coreopsis, Delphinium, Digitalis, Helianthus, Hosta, Iris, Liatris, Lupinus, Papaver, Platycodon, Rudbeckia and Scabiosa.
Symptoms: Pre- and postemergent damping-off, crown rot, and blighting of foliage and petioles. Small, hard, irregular, black structures called sclerotia may be present on or in plant tissue (especially inside stem and petiole tissue). White, fluffy growth on affected plant parts is most readily visible in high humidity.
Spread: Sclerotia, long-term survival structures, are found in soil and on plant debris. The disease is primarily spread when these structures are moved. Disease can also be spread when infected plant material is moved.Under certain environmental conditions, mushroomlike structures (apothecia) are produced. These release air- borne spores.
Management: Field soil should be sterilized before use in growing media. Susceptible crops should not be grown in areas with a history of white mold problems. Additionally, good sanitation is important to limit spread. Control weeds in production areas – some weeds are hosts to S. sclerotiorum. Fungicide drenches can protect plants from infection.