Penicillium rot of gladiolus

The disease known as Penicillium rot is caused by the fungus Penicillium gladioli. It is one of the most common storage diseases affecting corms, specifically targeting bulbous crops that are stored under improper conditions throughout the dormant winter period.

The primary host for this pathogen is the gladiolus plant. While the fungus often persists in the soil, it predominantly infects corms through wounds, cuts, or damaged skin that occur during harvesting, transport, or due to poor curing processes after cleaning.

Symptoms typically include the formation of small, sunken yellowish to reddish-brown lesions on the corm surface. As the infection progresses, especially in high humidity, these spots become covered with a characteristic powdery, blue-green mass of spores, eventually turning the internal tissue into a soft, dry rot.

Environmental conditions are critical for the spread of the fungus. High relative humidity (exceeding 70%), inadequate ventilation in storage facilities, and cool temperatures between 5°C and 15°C create an ideal environment for the mycelium to thrive and colonize healthy corms.

Control measures emphasize sanitation and environmental management. Growers should prioritize gentle harvesting to avoid mechanical damage, ensure rapid and thorough drying (curing) of corms before storage, and use appropriate fungicide treatments to protect against latent infections.

• Sanitizing storage racks and containers.
• Sorting corms to remove any showing signs of infection.
• Maintaining optimal airflow and low humidity during storage.
• Applying fungicides suitable for bulb treatment.