Basal stem and root rot

Basal stem and root rot, caused by the fungal pathogen Ceratocystis, is a destructive disease that targets the vascular and structural integrity of host plants. The pathogen primarily attacks the root system and the stem base, leading to systemic disruption that rapidly impacts the plant's physiological functions and often results in total crop loss.

This pathogen has a wide host range, affecting various ornamental and agricultural plants. Among the most susceptible crops is the poinsettia, where the infection can spread rapidly in greenhouse environments, particularly affecting newly rooted cuttings and young plants that have not yet established a robust root system.

Key symptoms of the disease include progressive wilting, leaf chlorosis, and the formation of necrotic lesions near the soil line. As the infection progresses, the tissues at the base of the stem become darkened and soft, eventually forming a girdling canker. When the roots are inspected, they appear stunted, blackened, and necrotic, having lost their functional capacity to absorb nutrients.

The development of Ceratocystis is heavily favored by warm, moist conditions and poor substrate drainage. The fungus acts as a soil-borne pathogen, spreading through contaminated water, infested soil particles, and human activity. Once established in the growing environment, it is notoriously difficult to eradicate, requiring aggressive sanitation measures.

Management and prevention focus on eliminating sources of inoculum and optimizing environmental conditions:

• Implement strict sanitation protocols for all greenhouse equipment and containers.
• Utilize high-quality, disease-free, and pasteurized growing media.
• Avoid over-irrigation to maintain appropriate oxygen levels in the root zone.
• Promptly remove and destroy infected plant debris to prevent inoculum buildup.
• Apply targeted fungicide treatments as part of an Integrated Pest Management program.