Sclerotinia rot

Sclerotinia rot, commonly known as white mold, is a devastating fungal disease caused by the pathogen Sclerotinia sclerotiorum. As a necrotrophic pathogen, it invades and kills plant tissues, leaving behind hard, black survival structures called sclerotia. These sclerotia can persist in the soil for several years, creating a long-term reservoir for the disease.

This fungus has an exceptionally wide host range, attacking over 400 plant species including winter oilseed rape, celery, peanuts, asparagus, Indian mustard, and turnips. Ornamental plants such as Anemone coronaria and Slipper Flower are also highly susceptible. Its broad host range makes it one of the most difficult pathogens to manage in diversified agricultural systems.

The primary symptom is the appearance of water-soaked lesions that quickly develop a dense, white, cotton-like mycelial growth. As the disease progresses, the infected tissue decays and rots. Eventually, black sclerotia form within the rotted stems or on the plant surface, which are diagnostic indicators of the presence of the pathogen in the field.

Disease development is favored by cool, wet weather and high humidity. Spore dispersal is most active during flowering periods when petals act as a substrate for the fungus to colonize before it spreads to healthy plant parts. Poor air circulation in high-density crops or excessive canopy growth creates an ideal microclimate for rapid disease spread.

The impact of Sclerotinia rot on agricultural productivity is severe, leading to significant yield losses and reduced crop quality. Management strategies focus on breaking the disease cycle through crop rotation, removing crop residues, and controlling broadleaf weeds. Chemical control involves the timely application of fungicides during the flowering window to prevent the primary infection of petals.

• Utilizing disease-free and treated certified seeds.
• Maintaining optimal planting density for airflow.
• Integrating biological controls like Coniothyrium minitans.
• Implementing deep tillage to bury sclerotia.