Borzia trilocularis

Borzia trilocularis is a species of filamentous cyanobacteria that, under certain environmental conditions, can act as a plant surface pathogen. While typically classified as an aquatic or soil organism, its ability to colonize moist plant surfaces makes it an issue of concern for greenhouse management and intensive crop production.

The biology of Borzia trilocularis is characterized by the formation of trichomes that proliferate rapidly in high-humidity environments. These organisms do not directly parasitize the plant tissue in the traditional sense of fungal pathogens but rather create an epiphytic layer that interferes with the plant's vital biological functions.

Susceptible crops include various greenhouse vegetables, seedlings, and ornamental plants kept under high-moisture regimes. The pathogen tends to colonize foliage, stems, and surfaces that are frequently wet due to condensation, overhead irrigation, or lack of proper soil drainage, creating a micro-ecosystem conducive to its growth.

The primary symptom is the presence of a slick, dark green, or blue-green algae-like film on the plant surface. Unlike typical fungal mold, this layer has a distinct mucilaginous texture. Affected leaves may show symptoms of chlorosis, necrosis, and reduced vigor, primarily caused by the blockage of stomata, which inhibits photosynthesis and gas exchange.

Managing this condition requires strict environmental control. To prevent and treat the infestation, consider the following steps:

• improve greenhouse ventilation and airflow
• regulate humidity levels to prevent condensation
• switch to drip irrigation to keep foliage dry
• apply copper-based fungicides to inhibit cyanobacterial growth
• maintain sanitary conditions in growing media