Fragilariophyceae algae

Fragilariophyceae are a class of diatom algae that, while not acting as traditional pathogens, represent a significant issue in commercial plant production, particularly in hydroponic systems and nursery irrigation setups. They colonize moist surfaces, pipes, and substrates, often disrupting the operational efficiency of agricultural facilities.

The nature of their impact is primarily competitive and mechanical. By creating dense biofilms on root zones and irrigation components, these organisms restrict oxygen availability, clog emitters, and steal mineral nutrients intended for the crop. This competition leads to nutrient imbalances and physical stress on the plants.

Symptomatology involves the appearance of brown or yellowish-green coatings on moist surfaces, such as rockwool, perlite, or the interior of irrigation tubing. Infested root zones typically show stunted development, with the root surface feeling slimy, which eventually results in reduced water uptake and secondary root degradation.

The development of Fragilariophyceae is driven by specific environmental conditions: high light intensity reaching the nutrient solution, excessive nutrient availability, and poor circulation. In hydroponic setups, these algae thrive when reservoirs remain exposed to ambient light, allowing them to rapidly form massive colonies.

Management strategies focus on excluding light and maintaining strict sanitary conditions within the growing system:

• Light-shielding all nutrient reservoirs and distribution lines to stop photosynthesis.
• Implementing regular disinfection protocols using approved sanitizers to clear pipes and tanks.
• Using UV sterilization units to eliminate algae spores from recirculating water.
• Optimizing irrigation frequency to prevent prolonged saturation of the substrate surface.