Anacystis cyanea

Anacystis cyanea is a species of unicellular cyanobacteria that poses a significant challenge in hydroponic systems, aquaculture, and rice production. Unlike typical fungal pathogens, this organism functions as an invasive biological agent that triggers water blooming, disrupting the physiological balance of the plant environment through competition and toxin production.

The organism primarily affects crops grown in hydroponic solutions or saturated soils. By proliferating rapidly in nutrient-rich media, it competes with crop roots for dissolved oxygen and essential micronutrients. This competition often leads to a decline in the metabolic activity of the plants, resulting in stunted growth and diminished crop quality.

Symptoms of an Anacystis cyanea infestation include the development of a distinct blue-green film or mat on the surface of the water or substrate. Plants affected by these cyanobacteria show signs of root decay, discoloration, and slimy root surfaces. As the infestation progresses, the foliage often exhibits chlorosis, wilting, and eventually total necrosis due to root asphyxiation caused by the algal biofilm.

The proliferation of Anacystis cyanea is driven by favorable environmental factors such as high intensity of light, elevated water temperatures (typically above 20°C), and an surplus of nitrogen and phosphorus in the nutrient solution. Poor aeration and lack of water circulation are critical factors that allow these colonies to establish themselves quickly in commercial greenhouse systems.

Integrated management is essential to control this threat and ensure plant health:

• Utilizing UV-C sterilization units in irrigation and nutrient circulation systems.
• Implementing light-blocking covers on water reservoirs to inhibit photosynthesis.
• Performing regular mechanical cleaning and chemical disinfection of hydroponic equipment.
• Monitoring and adjusting nutrient concentration to prevent excessive accumulation of solutes.