Hydrococcaceae

Hydrococcaceae is a family of cyanobacteria that significantly affects agriculture, particularly in aquaculture and deep-water hydroponic systems. While not a pathogenic fungus in the traditional sense, this family acts as a biological contaminant that disrupts the root environment, limiting nutrient uptake and inhibiting normal plant development.

The biological nature of this condition involves the rapid colonisation of root surfaces by colonies of cyanobacteria. These organisms thrive by utilising the same nutrients as the target plants. By forming a dense, biofilm-like layer around the roots, they prevent oxygen exchange and nutrient absorption, which is often misidentified as root rot or other fungal infections.

Commonly affected crops include rice in flooded fields and leafy greens grown in hydroponic systems such as NFT (Nutrient Film Technique) or DWC (Deep Water Culture). The presence of Hydrococcaceae is often an indicator of imbalances in the irrigation water quality or excessive exposure to sunlight within the nutrient delivery lines.

Symptoms of infestation are characterized by the appearance of a slimy, often dark blue or green coating on roots and equipment surfaces. This biological film can obstruct pumps and irrigation emitters, causing systemic plant stress. Visible consequences include yellowing (chlorosis), stunted root growth, and wilting, which occur despite adequate irrigation levels.

Management and prevention focus on eliminating the conditions that favour cyanobacterial bloom. High phosphate levels and improper lighting are the primary drivers of growth. Maintaining high water hygiene and controlling the nutrient concentration is essential for preventing the rapid spread of Hydrococcaceae in both greenhouse and open-field aquatic farming environments.

• Regular UV water sterilisation to kill algal spores.
• Blocking light penetration to nutrient reservoirs and pipes.
• Maintaining proper dissolved oxygen levels in the nutrient solution.
• Routine mechanical cleaning of hydroponic channels and reservoirs.
• Monitoring phosphate concentrations to avoid nutrient surplus.