Mycoleptodiscus crown and root rot

Mycoleptodiscus crown and root rot is a destructive fungal disease caused by the pathogen Mycoleptodiscus terrestris. This fungus primarily invades the root system and crown area of the plant, disrupting water and nutrient uptake through the destruction of vascular tissues.

The disease primarily impacts legume crops, posing a significant threat to agriculture. It is most frequently identified in alfalfa (Medicago sativa) and red clover (Trifolium pratense), leading to reduced longevity and productivity of established stands.

Symptoms of the infection include brown to black necrotic lesions on the taproot and crown. As the disease progresses, the infected tissues become soft and decayed, causing the plant to show signs of wilting, chlorosis, and eventual collapse of the entire crown area.

The development and spread of Mycoleptodiscus terrestris are heavily influenced by environmental conditions, particularly high soil moisture and warm temperatures. The fungus resides in soil and crop debris, making it a persistent threat in fields where susceptible hosts are grown continuously.

The economic impact of this pathogen is severe, as it causes plant mortality and patchiness in perennial fields, which necessitates earlier stand removal than planned. Effective management is essential to maintain field health and ensure long-term agricultural productivity.

• Rotate affected fields with non-legume crops to break the disease cycle.
• Improve soil drainage to prevent prolonged moisture accumulation.
• Select resistant or tolerant cultivars when available.
• Practice good field sanitation by removing or burying debris after harvest.