As the disease progresses, desiccated plant tissues appear bleached ( Fig. Affected tissues may develop a soft watery consistency, and a thick white mycelium forms, often both inside and outside the tissue. 4), which causes distal portions of the plant to wilt and then become necrotic ( Fig. As the lesions enlarge, affected stems may be girdled ( Fig. Initially, lesions appear as water-soaked spots that expand irregularly and indeterminately. infect upper portions of plants to cause diseases such as flower blights, stem rots, fruit rots, and head blight. 3), which are most commonly found on the outer surface of the diseased tissue, but sometimes inside of soft host tissues or cavities such as floral receptacles, fruits and the pith of stems. These clumps eventually mature into hard black sclerotia ( Fig. Secondary symptoms such as wilting, bleaching, and shredding also can be observed on above-ground tissues including stems, leaves, petioles and reproductive organs.Īt later stages of the disease, the cottony hyphae of the pathogen aggregate into (typically) pea-sized clumps of mycelium ( Fig. The hyphae produce enzymes and oxalic acid, creating water soaked lesions, frequently with a distinct margin. White mold is easily identified by the characteristic white cottony mycelium of the pathogen that grows on the surfaces of infected aerial tissues ( Fig. Sclerotinia homoeocarpa, but is likely to be reclassified as Lanzia or Moellerodiscus. The pathogen that causes dollar spot of turf historically has been called Sclerotinia species cause diseases other than white mold. The pathogens are favored by cool, moist conditions, but show surprisingly broad ecological distributions. Sclerotinia spp., generally known as 'white mold', can affect hundreds of plant species including many important crops. HOSTS: legumes, sunflowers, canola, most vegetables, tobacco, many flowering bedding plants, and stone fruits Related Lesson: Sclerotinia sclerotiorum Diseases of Sunflower (White mold) Heffer Link, V., and K.
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