Water Hyacinth - Control

Control

Water hyacinth can be controlled using three methods:

Chemical Control

The application of herbicides for controlling water hyacinth has been carried out for many years and it has been found that there is a good success rate when dealing with small infestations. A main concern when using herbicides is the environmental and health related effects, especially where people collect water for drinking and washing.

Physical Control

Physical control is performed by land based machines such as bucket cranes, draglines, or boorm or by water based machinery such as aquatic weed harvester, dredges, or vegetation shredders. Mechanical removal is seen as the best short-term solution to the proliferation of the plant. It is however costly and requires the use of both land and water vehicles.

Biological Control

As chemical and mechanical removal is often too expensive and ineffective, researchers have turned to biological control agents to deal with water hyacinth. The effort began in the 1970s when USDA researchers released three species of weevil known to feed on water hyacinth into the United States, Neochetina bruchi, N. eichhorniae, and the water hyacinth borer Sameodes albiguttalis. Although meeting with limited success, the weevils have since been released in more than 20 other countries. However, the most effective control method remains the control of excessive nutrients and prevention of the spread of this species.

May 2010 the USDA’s Agricultural Research Service released Megamelus scutellaris as a biological control insect for the invasive waterhyacinth species. Megamelus scutellaris is a small planthopper insect native to Argentina. Researchers have been studying the effects of the biological control agent in extensive host-range studies since 2006 and concluded that the insect is highly host-specific and will not pose a threat to any other plant population other than the targeted water hyacinth. Researchers also hope that the biological control will be more resilient than existing biological controls to the herbicides that are already in place to combat the invasive water hyacinth.