Sclerotinia sclerotiorum
Fungal disease affecting many crops, causing white cottony growth and hard black sclerotia. Particularly damaging to beans, lettuce, and cole crops.
Water-soaked lesions on stems and leaves. White cottony fungal growth. Hard black sclerotia inside stems. Wilting and plant death. Bleached, shredded stems.
Soil-borne fungus. Sclerotia germinate to produce spore-bearing structures (apothecia) that release airborne spores.
Airborne spores from apothecia. Contaminated seed. Infected plant debris. Sclerotia persist in soil 5-10 years.
Cool to moderate temperatures (60-75°F). High humidity. Dense canopy. Prolonged wet conditions during flowering.
Rotate with non-host crops (corn, small grains) for 3-4 years. Avoid dense plantings. Control weeds. Plant resistant varieties when available.