Orange County

Town using ‘safe’ herbicide to combat infestation of alien plant invader in Eno River

Mats of the non-native, invasive hydrilla is pictured in the Eno River downstream of Hillsborough.
Mats of the non-native, invasive hydrilla is pictured in the Eno River downstream of Hillsborough. Town of Hillsborough

The Town of Hillsborough on Friday announced that it had begun applying a “safe” herbicide to battle an infestation of an invasive aquatic plant in the Eno River in Hillsborough. The treatment will continue through September.

According to the town, the herbicide Sonar Genesis is being applied in a concentration “well below” limits set by the Environmental Protection Agency and said it is safe for humans, fish and wildlife. Property owners adjacent to the treated section of the river were notified by the Eno River Hydrilla Management Task Force and cautioned regarding the use of river water for irrigation during treatment for the Asiatic plant hydrilla.

The treatment follows a two-year pilot program that showed significant reduction of the plant without impacts to the rest of the ecosystem or to human health. Hydrilla grows rapidly, creating thick mats on the surfaces of lakes, rivers and other waterways and impeding recreational activities and the health of fish and wildlife in the area. Sixteen miles of the Eno River are being targeted, from Hillsborough to Roxboro Road/N.C. 501 in Orange and Durham counties.

Hydrilla was discovered in the Eno River watershed in the early 1990s in Lake Orange, which is upstream of Hillsborough. In 2009, biologists confirmed hydrilla in the Town of Hillsborough’s reservoir — West Fork Eno Reservoir. The N.C. Division of Water Resources is managing hydrilla in both reservoirs as it can clog intakes for supplying drinking water and irrigation.

The Town of Hillsborough is helping to fund the treatment in the Eno River, and Stormwater and Environmental Services Manager Terry Hackett is a member of the hydrilla management task force.

For more information, contact Hillsborough’s stormwater and environmental services manager at 919-296-9621.