Grass-wrack pondweed

Grass-wrack pondweed (lat. Potamogeton compressus) belongs to the Potamogetonaceae family. It is a perennial aquatic plant that lives submerged, developing primarily in still or slow-moving freshwater bodies. Biologically, this species is a typical hydrophyte, adapted to life in an aquatic environment using rhizomes to anchor itself in bottom sediments.

This plant is frequently found in irrigation canals, drainage systems, ponds, and lakes. Grass-wrack pondweed causes significant issues in agriculture by clogging canals intended for crop irrigation. When it spreads, the dense stands drastically reduce the hydraulic capacity of water structures and slow down water flow.

The biology of the plant is characterized by intensive vegetative reproduction via underground shoots and overwintering buds (turions). The stems have a distinctly flattened shape, which is reflected in its common name. The active growth period occurs during the spring and summer season, when the plant forms dense biomass that hinders the normal operation of water facilities.

The harmfulness of the pondweed manifests as an obstruction to water delivery to fields, leading to disruptions in irrigation schedules. Furthermore, accumulations of decomposing pondweed biomass can lead to a decrease in dissolved oxygen levels, negatively impacting aquatic fauna. The siltation of channels caused by water retention by the plant requires additional expenditures on cleaning.

Control measures include both mechanical and chemical methods. Agrotechnically, it is effective to perform regular mechanical cleaning of channel beds before the start of active flowering. For chemical control, contact or systemic aquatic herbicides are used. An important preventative technique is maintaining an optimal water flow velocity in canals, which makes it difficult for the pondweed to take root.

• Mechanical harvesting of aquatic vegetation.
• Regular cleaning and deepening of irrigation canals.
• Application of specialized aquatic herbicides.
• Maintenance of water flow velocity.