Thunberg's pondweed

Thunberg's pondweed (Potamogeton thunbergii) belongs to the Potamogetonaceae family. This perennial aquatic rhizomatous plant is classified as a significant weed in irrigation systems and flooded agricultural lands, particularly in rice cultivation regions.

This species is mainly found in East and Southeast Asian countries. From an agronomic perspective, it poses a severe threat to rice paddies because its dense growth in the aquatic environment competes with rice plants for sunlight and essential nutrients, thereby reducing overall crop productivity.

The biology of the plant is centered on its robust rhizome system, which allows it to overwinter successfully in bottom sediments. It reproduces both vegetatively through rhizome fragmentation and via seeds. The plant has a high capacity for colonizing large areas of shallow water rapidly, creating thick, invasive mats.

The primary harmful impact stems from its ability to outcompete cultivated crops for physical space and resources within the water column. Excessive growth of this weed makes mechanical agricultural operations difficult, obstructs water flow in irrigation channels, and accelerates the sedimentation process in field ditches.

Control strategies involve a combination of cultural and chemical measures. Cultural practices include proper field leveling, thorough soil tillage to physically disrupt rhizomes, and precise management of water levels during the season. Chemical control relies on applying systemic herbicides that are specifically approved for use in aquatic rice-growing environments.