Oscillatoriaceae algae

Oscillatoriaceae are a family of filamentous cyanobacteria, known as blue-green algae, which in agronomy are classified as pathogenic organisms that cause the formation of a specific film on the soil surface and in hydroponic systems. They are not a classic fungal pathogen, but their mass development inhibits the growth of crops by blocking gas exchange and nutrient uptake.

This object most often affects seedlings in greenhouses, hydroponic installations, and open areas with waterlogged soil. It poses a particular danger to young rice crops, vegetable crops during the seedling stage, and ornamental plants in containers where drainage is compromised.

Symptoms of infestation appear as a dense, slimy film of a dark blue-green or brown color on the surface of the substrate. During their life cycle, these algae release toxins that inhibit seed germination and suppress the root system, leading to wilting of seedlings, greening, and acidification of the topsoil layer.

Conditions for the active spread of Oscillatoriaceae include excessive soil moisture, stagnant water, high light intensity combined with an excess of mineral fertilizers, especially phosphorus and nitrogen. Poor soil aeration and a lack of proper ventilation in greenhouses accelerate the colonization of the substrate by these organisms.

Protection measures include strictly following watering schedules, improving drainage, and using high-quality substrates. To prevent spread, the following are used:

• Regular loosening of the topsoil to destroy the algal film.
• Adjustment of mineral fertilizer dosage.
• Application of fungicides with algicidal properties in cases of severe infestation.
• Disinfection of tools and containers that come into contact with contaminated soil.