Gloeobacterales

Gloeobacterales are a unique order of cyanobacteria that, under specific conditions, can act as a complicating agent in plant diseases. Unlike typical plant pathogens, these microorganisms lack thylakoids, making them a primitive form of photosynthetic bacteria capable of colonizing leaf surfaces and damp areas of plant bark.

The primary crops susceptible to the influence of this group include moisture-loving ornamental plants, mosses, and certain greenhouse vegetable crops. Colonization occurs in areas where the epidermis is compromised or in micro-environments where condensation accumulates, providing a suitable substrate for bacterial biofilm development.

Infection symptoms manifest as the formation of a dense, slimy coating with a blue-green or dark-gray color. As colonies expand, these biofilms can obstruct stomata, disrupting normal gas exchange and photosynthesis, which eventually leads to chlorosis and stunted growth of the plant's vegetative mass.

Optimal conditions for development and spread include extremely high air humidity and poor air circulation. Bacteria are dispersed by water droplets, wind, and contaminated equipment. High temperatures combined with stagnant moisture promote rapid population growth and the colonization of healthy plant tissues.

Protection strategies include strict adherence to ventilation protocols in greenhouses and preventing soil waterlogging. Regular sanitation of surfaces using disinfectants is recommended, along with the application of copper-based agents to prevent the establishment of bacterial biofilms on the surfaces of leaves and stems.