Sclerotinia rot

Sclerotinia rot, commonly known as white mold, is a devastating fungal disease caused by various species within the Sclerotiniaceae family, particularly the Sclerotinia genus. The pathogen is notorious for producing sclerotia—hard, black survival structures that remain dormant in the soil for several years, making the disease difficult to eradicate.

The host range of Sclerotinia is exceptionally broad, affecting over 400 species of plants. Major agricultural crops significantly impacted include sunflowers, canola, soybeans, dry beans, and a wide variety of vegetables such as lettuce, carrots, and potatoes, leading to massive losses in global food production.

Visible symptoms often include the development of a fluffy, white mycelial growth on affected stems, leaves, or pods. As the fungus advances, the infected tissues become soft and watery, eventually turning brown and necrotic. The formation of hard, black sclerotia inside or on the surface of the plant tissue is a hallmark diagnostic feature.

The infection thrives in cool, moist environments where relative humidity is consistently high. Spore production and dissemination are favored by prolonged leaf wetness and moderate temperatures. The fungus can infect plants through direct contact with germinating sclerotia in the soil or through wind-borne spores landing on senescent flower petals.

Effective management requires an integrated approach. Essential practices include crop rotation with non-host species, such as cereals or grasses, to deplete soil-borne inoculum. Furthermore, the use of certified disease-free seeds, adequate plant spacing to promote airflow, and the timely application of fungicides are crucial for mitigating the damage caused by this resilient pathogen.

• Deep plowing to bury sclerotia deep into the soil profile.
• Application of biological control agents like Coniothyrium minitans.
• Weed management to eliminate alternative host plants.
• Monitoring weather patterns during the flowering stage of crops.