Aquatic weeds are unwanted and undesirable vegetation that grow and reproduce in an aquatic environment, like ponds and lakes, and affect its usefulness. While limited growth of these plants is valuable in maintaining water quality, providing shade, shelter, and natural food to many fishes, oxygenating the water, and reducing turbidity, their uncontrollable growth can prove detrimental to the water body and those inhabiting it. The aquatic weed categories include algae, floating weeds, emerged weeds, and submerged weeds.

Aquatic weeds covering a large surface area (more than 25%) make spending time in the pond or lake less enjoyable and threaten fishes and wildlife. Regular weed removal is an essential activity helpful in restoring weedy lakes or ponds and increasing their safety and usability. However, not many people think about weeds until they create an unsightly mess and clog up the waterways.

Aquatic weed problems

Failure to control aquatic weed growth or leaving them unchecked can lead to various issues. Some of the threats posed by these water plants include:

• Restricted activities like swimming, fishing, boating, and water sports
• Lead to unpleasant taste, foul odor, and discoloration in the water
• Spoil the aesthetic appeal of the water body
• Cause water back up
• Affect adequate light and nutrients penetration 
• Depletes oxygen in the pond and lead to fish kills
• Impede water flow
• Water quality impairment
• Stunted fish growth
• Provide an ideal breeding ground for mosquitoes

Aquatic weed removal is vital to avoid all these problems.

Methods to control aquatic weeds

Aquatic weed removal involves taking appropriate steps to manage uncontrolled weed growth while preserving the water body. Pond owners use several methods to eradicate aquatic weeds. The methods used depend on water use, the type of weed to be removed, and the non-target plants. An effective weed removal process can include using one or a combination of the following ways:

Physical weed removal

Physical weed removal is more suitable for small ponds or areas where machines cannot reach. It involves using hands to cut, pull, or rake weeds. You can use ropes, nets, or bamboo poles to remove floating weeds. Physical weed removal produces immediate but short-lived results. It consumes more time and is labor-intensive. The method can also include using specialized harvesting machinery to cut, collect, and remove weeds. The mechanical method can be used in addition to chemical control. Experts suggest applying herbicide before physical removal for efficient removal.

Biological control

Biological weed control involves introducing herbivorous or phytophagous fishes, weed pathogens, or insects in areas with high invasive plant growth. It is a cheap, easy, and popular method, but at the same time, it is vital to use this method cautiously as the long-term effect of the introduced species to the water body is hard to forecast.

Chemical control

In the chemical control method, chemicals or weedicides are used to eradicate weeds. Special care should be taken to ensure that the weedicides or herbicides used are non-toxic to fishes, should not pollute the aquatic ecosystem, and should only eliminate weeds at low concentrations. The herbicides used are either systematic or contact in nature. Different weedicides can be used depending on the type of weed present.

While applying aquatic weed control, experts recommend not to remove all the plants. Before using any weed removal process, it is essential to identify the invasive species and use the appropriate product for the situation.