Potato Fusarium dry rot

Causal agent and disease nature: Fusarium dry rot in potatoes, caused by the fungus Gibberella cyanogena (anamorph Fusarium solani), is a destructive disease that impacts both field cultivation and post-harvest storage. This fungal pathogen spreads through soil and infected tubers, colonizing the plant's vascular tissues and causing progressive decay that significantly reduces the marketability and yield of the crop.

Host range and infection: The primary host for this pathogen is the potato plant, though it can affect a wide variety of solanaceous crops. Infection usually occurs through wounds on the tubers sustained during harvest or transport, or through the root system during the growing season, allowing the fungus to enter the internal tissues and initiate decay processes.

Symptoms and signs: Field symptoms include leaf chlorosis, curling, and wilting, often starting from the top of the canopy. When stems are cut, a dark discoloration of the vascular ring is typically observed. During storage, tubers develop sunken, wrinkled lesions, underneath which the flesh becomes brown, dry, and necrotic, often covered with characteristic white or pinkish mold growth.

Development conditions: The disease thrives in warm and moist conditions, especially when high soil temperatures are combined with moisture stress. In storage facilities, the pathogen spreads most rapidly when temperatures are too high and ventilation is inadequate, creating a humid microclimate that facilitates the rapid colonization of tuber tissues by fungal mycelium.

Protection and prevention measures: Effective management of Fusarium dry rot requires an integrated approach focusing on sanitation and handling. Essential control practices include:

• Utilizing certified, disease-free seed tubers for planting.
• Carefully handling tubers to minimize bruising and wounding during harvest.
• Ensuring proper wound healing (suberization) by curing potatoes before long-term storage.
• Maintaining cool, well-ventilated storage environments to inhibit fungal activity.
• Implementing rigorous crop rotation practices to reduce inoculum pressure in the soil.