Potato tuber rot

Potato tuber rot is a collective term for various pathological conditions caused by fungi, bacteria, and oomycetes. Major pathogens include Fusarium species (responsible for dry rot), Phytophthora infestans (late blight), Phoma species, and soft rot bacteria like Pectobacterium carotovorum. These organisms infect tubers throughout the growth cycle and are particularly devastating during post-harvest storage.

This disease primarily affects potato crops, though its pathogens can persist in soil and infect other related solanaceous plants. The cycle of infection typically starts in the field, where spores or bacteria contaminate the tubers through soil contact or irrigation. Infected seed potatoes serve as a primary source of inoculum, perpetuating the disease from one season to the next.

Symptoms are diverse: dry rot manifests as sunken, dark, wrinkled lesions on the skin, often accompanied by white or pinkish fungal spores within the tuber cavities. Conversely, bacterial soft rot causes tissue to liquefy, resulting in a foul-smelling, mushy consistency. In advanced stages, the internal tissue is completely broken down, and the tuber loses all structural integrity, often affecting neighboring healthy potatoes in storage.

Development and spread are facilitated by environmental stress and poor storage conditions. High relative humidity (exceeding 85%), inadequate ventilation, and temperatures above 5°C create an environment conducive to pathogen growth. Mechanical damage, such as cuts or bruises sustained during harvest, provides entry points for pathogens, significantly increasing the risk of rot development in bins or cellars.

The economic impact of tuber rot is substantial, potentially leading to total crop loss if not managed properly. Effective prevention strategies focus on using resistant cultivars, implementing strict crop rotation, and ensuring tubers are dry and cured before storage. Chemical seed treatments and maintaining optimal airflow in storage facilities are critical for minimizing post-harvest decay and preserving the quality of the marketable crop.

• Harvesting tubers only during dry, cool weather.
• Careful handling to minimize surface nicks and cuts.
• Regular inspection of stored tubers for signs of decay.
• Sanitizing storage containers and warehouse walls.
• Maintaining proper temperature and humidity control in storage.