Gloeocapsa sanguinea

Visually, the colonies appear as dense, shiny films or small, localized growths. Upon drying, they become brittle, lose their luster, and darken, forming a crust on the substrate surface.

The coating can spread to structural elements of greenhouses, creating an unfavorable environment for the crops being grown. In areas of high concentration, a specific musty odor is often observed.

When leaves touching the soil surface are affected, spots form on them, hindering normal respiration and photosynthesis, which ultimately suppresses the plant's overall development.

The expansion of these colonies is often accompanied by the displacement of beneficial soil microflora, leading to the degradation of the topsoil layer in containers or nurseries.

The causative agent is the blue-green alga Gloeocapsa sanguinea. It is a unicellular or colonial microorganism belonging to the Cyanobacteria phylum, possessing the ability for active photosynthesis.

The characteristic red pigment (phycoerythrin) protects the algal cells from excessive ultraviolet radiation, allowing them to survive in open, well-lit environments.

The cells are surrounded by a robust mucilaginous sheath that stores water and nutrients, ensuring the survival of the colony during periods of temporary drought.

Reproduction occurs through cell division within the mucilaginous matrix, which facilitates the rapid expansion of the colony area under favorable conditions.

This organism is often viewed not as a pathogen in the traditional sense, but as an epiphytic organism capable of mass development when agricultural practices are neglected.

The primary factor for development is constant excessive moisture in the soil and on the surfaces where the algae settle. Poor substrate drainage creates an ideal environment for vegetative growth.

High humidity in greenhouses plays a significant role. The lack of regular ventilation and the stagnation of air masses provoke the rapid expansion of algal colonies.

Sufficient light is a growth catalyst, as Gloeocapsa sanguinea is a photoautotrophic organism and requires light to maintain its vital activities.

The availability of mineral elements in the substrate, especially nitrogen and phosphorus, significantly accelerates the development of algal films on the soil surface.

Soil acidity also influences distribution: this alga often prefers slightly acidic or neutral environments that are rich in organic residues.

The main danger lies in the creation of a physical barrier on the soil surface, which hampers aeration of the plant root system and causes oxygen deprivation.

The slime secreted by the algae alters the structure of the topsoil layer, promoting acidification and the formation of a dense crust that prevents water from reaching the roots.

The development of colonies on stems leads to rot due to constant contact with the moist mass, which opens a gateway for secondary bacterial and fungal infections.

In commercial greenhouses, the mass development of algae reduces the marketability of seedlings and potted plants, making them unsuitable for sale due to the unattractive coating.

The accumulation of algal biomass can attract pests such as fungus gnats, which lay their eggs in moist organic environments.

The primary measure is to establish a proper watering schedule, prevent water stagnation, and ensure high-quality drainage in containers or greenhouses.

Regular loosening of the topsoil layer is necessary, as it breaks the slimy film and promotes surface drying, thereby suppressing algal growth.

It is important to maintain ventilation to reduce relative air humidity, making conditions less suitable for the active growth of cyanobacteria.

In cases of severe infestation, it is recommended to replace the topsoil layer with fresh, porous substrate and to disinfect surfaces using copper sulfate solutions or specialized algicides.

Applying a layer of sand, fine expanded clay, or gravel as mulch effectively prevents direct contact of algae with light and limits their further spread.