Creeping bryozoan

Systematic position: The creeping bryozoan (Plumatella repens) belongs to the phylum Bryozoa, class Phylactolaemata, order Plumatellida, and family Plumatellidae. It is a colonial aquatic organism frequently found in freshwater environments, which can unintentionally colonize human-made water systems.

Crops affected: This species is primarily an economic pest in hydroponic setups, aquaponic systems, and greenhouse irrigation networks. While it does not consume plant tissue, it negatively affects plant health by obstructing nutrient supply lines, clogging filters, and fouling root zones in hydroponic tanks.

Biology and life cycle: Plumatella repens consists of branching tubes containing individual zooids. Its life cycle is notable for the production of statoblasts—dormant, resistant bodies that can survive extreme conditions, including freezing and drying. These statoblasts allow the organism to persist in infrastructure even when water is drained, leading to rapid re-colonization once the system is back in operation.

Nature of damage and harm: The primary harm is mechanical biofouling. Dense colonies reduce the diameter of pipes, causing pressure drops and uneven nutrient distribution. Furthermore, the accumulation of organic matter from the colony promotes the growth of secondary bacterial infections and fungi, which significantly increases the risk of root rot and other phytopathological issues in commercial crops.

Protection measures: Management strategies focus on sanitation and physical exclusion. It is essential to install fine filtration screens to prevent statoblast intake. Periodic treatment of water systems with non-phytotoxic disinfectants and aggressive flushing of pipes can help dislodge colonies. In recirculating systems, UV light treatment has proven effective in neutralizing larvae and inhibiting the development of new colonies.