Bacterial soft rot

Pathogen and disease type. Bacterial soft rot is caused by Dickeya chrysanthemi, a virulent phytopathogenic bacterium. This disease is characterized by the degradation of plant cell walls through the secretion of pectinolytic enzymes. The tissue breakdown causes rapid liquefaction, which is a classic symptom of bacterial soft rot infections.

Affected crops. This pathogen has a remarkably broad host range. It affects numerous ornamental plants, particularly chrysanthemums, and various vegetable crops. Notably, it poses a severe threat to onions and garlic, often causing significant losses during both the cultivation cycle and the post-harvest storage period.

Symptoms and signs. The initial symptom is the appearance of water-soaked, translucent lesions on the plant surface. As the infection progresses, the tissues become soft, watery, and mushy, frequently accompanied by a foul odor due to the activity of secondary saprophytic bacteria. In bulb crops, the decay usually starts at the neck or the basal plate.

Conditions for development and spread. The bacterium thrives in high-humidity environments and moderate-to-high temperatures. It spreads easily through contaminated soil, irrigation water, infested planting material, and infected tools. Any physical wound or damage to the plant tissue provides an entry point for the bacteria, significantly increasing the infection rate.

Harmfulness and preventive measures. The economic impact of this disease is high due to rapid crop destruction. Effective management includes using disease-free seeds and sets, implementing strict crop rotation, maintaining proper hygiene of storage facilities, and ensuring good air circulation. Chemical control using copper-based bactericides may be used as a prophylactic measure.