Cercomonads

Cercomonads (order Cercomonadida) are a group of single-celled soil protozoa (flagellates) that are increasingly recognized in modern agronomy as associated root system pathogens. These organisms typically inhabit the rhizosphere, feeding on bacteria, but under specific environmental conditions, they can trigger significant stress and growth inhibition in young plants.

These organisms primarily affect vegetable seedlings, cereal crops, and various technical plants. The highest risk occurs during seed germination and the early development of the primary root system, particularly in soils or substrates with high biological activity and excessive moisture where the natural microbial balance has been disrupted.

Symptoms of infestation often mimic common root rot diseases. Growers may observe browning of root hairs, stunted growth, leaf chlorosis, and general wilting of the vegetative mass despite adequate watering. Since these protozoa feed on beneficial rhizosphere bacteria, they compromise the plant's natural defense barriers, making it highly susceptible to secondary bacterial and fungal infections.

The development of Cercomonadida is fostered by waterlogged soil, poor aeration, and soil temperatures ranging from +15°C to +25°C. They multiply rapidly in soils rich in non-decomposed organic matter, which provides an abundant food supply. Spread occurs through irrigation water, contaminated substrate, and unsterilized agricultural tools used during planting or cultivation.

Protection strategies focus on strict moisture management and improved soil drainage. A key preventive practice is the application of biological agents based on Bacillus subtilis and Trichoderma, which establish competitive pressure and suppress the population of soil protozoa. Furthermore, rigorous sterilization of greenhouse substrates and the use of certified, treated seed material are essential for long-term crop health.

• Soil moisture management
• Biological control application
• Regular greenhouse sanitation
• Crop rotation cycles