Eustigmatales algae

Eustigmatales are an order of microscopic unicellular algae that can become a significant issue in agricultural production, particularly within greenhouse environments and hydroponic systems. While these organisms are generally benign, their uncontrolled proliferation on cultivation surfaces causes competitive stress, limiting the availability of oxygen and nutrients to the crops.

The causal agents belong to the class Eustigmatophyceae. These organisms utilize photosynthesis to thrive in aquatic environments, especially where there is an abundance of fertilizers and direct light. When they colonize substrate surfaces or roots, they alter the biological balance of the rhizosphere, often leading to secondary plant health complications.

Crops most susceptible to these algal infestations include leafy greens, vegetable seedlings, and various greenhouse-grown flowers. When irrigation systems keep the top layer of soil or the surface of growing media constantly moist, the environment becomes highly conducive to rapid algal growth, which can quickly spread across the entire cultivation area.

The symptoms of infestation are typically visible as a dense green, olive, or brown biofilm on the surface of the soil, rockwool, or other media. The plants often exhibit signs of stunting, wilting, or yellowing due to the restriction of gas exchange and nutrient absorption caused by the thick algal mats covering the root zone or the container surfaces.

Management and prevention focus on eliminating the conditions that trigger algal growth. Key practices include:

• blocking direct light from reaching nutrient reservoirs or substrates;
• maintaining strict irrigation scheduling to avoid surface water accumulation;
• optimizing hydroponic nutrient solution parameters;
• routine sanitation of irrigation lines and equipment;
• using environmental controls to lower humidity levels in the greenhouse.