Learn About Hydrilla

Hydrilla is an extremely aggressive aquatic plant that has the ability to grow up to a foot a day.  The thick, dense mats it forms obstructs boating, swimming and fishing.  Its invasiveness growth blocks sunlight that kills native plants and its excessive presence reduces oxygen in the water that can alter fish habitat.  Waterfowl feeding areas and fish spawning sites are at risk of elimination with Hydrilla overabundance and water treatment, power generation and industrial facilities can sustain damage when intakes are blocked.  Extreme and stubborn Hydrilla in an area can also lower the value of waterfront property.

The on-going fight against Hydrilla growing in Cayuga Lake in areas near Cayuga County has been underway now since 2017.  This year’s treatment began in late June 2018.  The approximate 60-day treatment plan includes a slow release of the herbicide fluridone through pellets applied below the water surface.  The fluridone is absorbed into the plant’s roots and ultimately disrupts the plant’s ability to use light during its photosynthesis process. Throughout the course of treatment, there are no health risks to residents who draw their water from Cayuga Lake.  For more information on Hydrilla and Fluridone, please visit the Cayuga County Health Department’s website at:   

The team from the Army Corps of Engineers leading the efforts on Cayuga Lake are reporting success with a noticeably reduced amount of Hydrilla throughout the treatment area.  The persistent nature of the plant however will mandate some form of management in the years to come.  

Early treatment is necessary in stopping the spread of Hydrilla.  In addition to scientific treatment strategies, the public too will be instrumental in identifying Hydrilla before it becomes too widespread making treatment impossible.  Residents should learn what the plant looks like and, when in the water, be on the lookout for it. For more information on how to identify and report possible Hydrilla infestations in Cayuga Lake, go to To report Hydrilla in other County lakes, send an email to or call 518-402-9405.

In addition, strands of Hydrilla can attach to boats and other equipment and is then transplanted to other areas and lakes if not appropriately cleaned off.  Residents should carefully remove any aquatic vegetation, no matter how small, from water crafts when leaving any water body to be sure they are not transporting Hydrilla or other invasive species from one lake to another.

You can also learn more about invasive species here.