Entophysalis

Entophysalis is a genus of cyanobacteria that, under specific environmental conditions, can act as a pathogen by colonizing the surface of plants and soil. These organisms form dense, mucilaginous colonies that can interfere with the physiological processes of the host plant, such as respiration and transpiration.

This pathogen primarily targets crops grown in waterlogged conditions, such as paddy rice, as well as plants in humid greenhouse environments. The presence of excessive moisture is the key factor enabling these microorganisms to spread across stems, roots, and soil surfaces.

The visual symptoms typically include the appearance of a dark, bluish-green, or brownish slime layer. Affected plants often exhibit signs of chlorosis, stunted growth, and a reduction in overall vigor due to the physical barrier created by the cyanobacterial mat on the plant surface.

Development and spread are facilitated by stagnant water, high humidity, and high levels of available nutrients in the soil. Prolonged exposure to sunlight further accelerates the growth of these colonies, making the problem particularly acute during hot and humid growing seasons.

Effective management and protection strategies include:

• Improving soil and greenhouse drainage to prevent stagnant water.
• Maintaining optimal humidity levels and ensuring adequate ventilation.
• Using chemical algaecides where permitted to control outbreaks.
• Regular cleaning of surfaces in protected cultivation to remove moisture reservoirs.