Hornwort

Hornwort (Ceratophyllum demersum), also known as coontail, belongs to the Ceratophyllaceae family. It is a submerged perennial aquatic plant that lacks true roots, instead relying on modified stems called rhizoids to anchor itself or drifting freely within the water column.

This species is widely distributed in stagnant or slow-moving freshwater bodies, such as ponds, lakes, and irrigation ditches. In agriculture, it is considered a significant weed, particularly in paddy fields and irrigation networks, where it interferes with water flow and general maintenance of hydrotechnical infrastructure.

The biology of hornwort is characterized by rapid vegetative reproduction. Because the stems are fragile, any broken segment can regenerate into a new plant. This resilience allows it to colonize vast areas of water quickly. It is capable of thriving in low light conditions and overwintering as dormant buds at the bottom of the water body.

The economic impact of this weed is primarily associated with the clogging of irrigation channels, which disrupts the consistent water supply required for crop production, especially in rice farming. Excessive growth also reduces water quality, promotes siltation, and creates operational difficulties for water pump stations and other agricultural machinery.

• Mechanical removal (dredging and harvesting) is the most common approach for channel maintenance.
• Biological control using herbivorous fish like the grass carp (Ctenopharyngodon idella).
• Drawdown and drying of irrigation channels during the off-season to kill submerged biomass.
• Application of aquatic-approved herbicides where manual or biological control is insufficient.