Dry rot canker

Dry rot canker, caused by binucleate species of the genus Rhizoctonia, is a significant fungal disease impacting various vegetable and root crops. These pathogens are characterized by their ability to cause localized tissue necrosis, which eventually develops into dry lesions that compromise the structural integrity of the plant's root system.

The primary hosts for this disease include forage beet and other sugar-producing varieties. The infection can occur throughout the growing season, but the most severe economic losses are often observed during the post-harvest storage period, where the fungus spreads from infected roots to healthy ones through contact.

Symptoms typically manifest as dark, depressed, dry lesions on the surface of the root crop. As the infection progresses, the internal tissues become woody, dry, and brittle. A distinctive feature of this type of rot is the lack of slimy decay or foul odors, which clearly differentiates it from bacterial soft rot infections.

The development of the disease is heavily influenced by soil moisture levels and temperature. Binucleate Rhizoctonia species are soil-borne pathogens that can persist in crop residues for extended periods. High levels of soil compaction, inadequate drainage, and injuries caused by soil pests facilitate the entry of the fungus into the plant tissues.

Protection strategies should focus on a multi-modal approach. Key preventive measures include crop rotation with non-host crops, ensuring well-drained soil conditions, and careful harvesting to prevent skin damage. In cases of high disease pressure, the use of targeted seed treatments with appropriate fungicides is necessary to protect young seedlings from early infection.

Regular monitoring of storage conditions is also vital. Maintaining low temperatures and high air circulation within storage facilities significantly slows down the mycelial growth of the fungus. Promptly removing visibly infected roots from the storage batch can also help mitigate further spreading of the disease.