Chryseobacterium indologenes soft rot

Pathogen and disease nature. Chryseobacterium indologenes is a Gram-negative, non-fermenting bacterium recognized as an emerging plant pathogen. While historically associated with human infections, it has been increasingly isolated from various crops, causing severe bacterial soft rot. Understanding its role as a phytopathogen is crucial for modern crop management strategies.

Affected crops. This bacterium exhibits a wide host range, primarily affecting vegetable crops such as onions, cucumbers, and various leafy greens. It can also colonize ornamental plants. In greenhouse environments, the close proximity of plants and consistent moisture levels create optimal conditions for the bacterium to spread and establish infection.

Symptoms and signs of infection. The characteristic sign of Chryseobacterium indologenes infection is the development of soft, watery rot on affected plant tissues. Infected areas often become translucent or mushy, showing rapid expansion. Under high humidity, a bacterial ooze may appear on the surface, accompanied by a foul odor due to the breakdown of plant cell walls.

Development and impact. The bacterium thrives in warm temperatures, typically between +25°C and +30°C, and requires high humidity for rapid colonization. The economic impact is severe, as the pathogen causes rapid tissue degradation, rendering produce unmarketable and leading to total crop loss during post-harvest storage and transport.

Control and prevention measures. Management relies on strict sanitation and environmental control. Essential measures include:

• Thorough disinfection of agricultural tools and greenhouse structures.
• Maintenance of optimal humidity levels and ensuring excellent airflow.
• Immediate removal and destruction of infected crop residues to prevent inoculum build-up.
• Utilization of healthy, certified seeds and implementation of crop rotation practices.