Cayuga Lake Inlet, N.Y. — In 2011, the aquatic plant Hydrilla verticillata, a damaging and fast-growing species, was discovered in the Cayuga Inlet by a volunteer aboard the Floating Classroom. If left untreated, the dense plant can block waterways and harm native plants and fish.

Local officials were quick to react when it was discovered and still continue to work to eradicate the foreign plant for fear that it will spread to other water bodies in New York or the Great Lakes. In places where the plant already has a hold, like Florida, it costs millions annually to treat it. A task force in Ithaca has administered herbicides since 2011 and has a plan in place to eradicate the plant completely within 10 years.


In 6 questions and 6 answers, here’s everything you need to know about the fight to rid our local waterways of Hydrilla. Click on the question to find your answer.

1 – What is Hydrilla and why is it a problem?
2 – Where does it come from?
3 – What is being done to eradicate it?
4 – How does Hydrilla affect the community?
5 – What is Hydrilla costing the community?
6 – This is a lot of text. Can I just watch a video?

(Did we miss your question? If so, email me at jstein@ithacavoice.com.)

1 – What is Hydrilla and why is it a problem?

Hydrilla is a dense plant that can thrive in almost any freshwater environment and, if left unchecked, can threaten native species very rapidly. It can grow up to a foot a day and can reach a length of around 25 feet underwater, according to the New York Invasive Species Clearinghouse. When the plant reaches the surface of the water, it begins to branch and grow horizontally, creating a dense mat and blocking sunlight for other plants. Its density can also deplete oxygen and create algae blooms, which threatens native plants and fish. Hydrilla spreads so easily because small pieces of the plant that break off can sprout their own roots. Often, these fragments go unnoticed and cling to boats or trailers.

Hydrilla can survive almost any lighting or nutrient conditions. For this reason, people like to use the plant in freshwater aquariums.


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2 – Where does it come from?

There are two biotypes of Hydrilla — dioecious and monoecious. Both originate in Asia but dioecious is believed to have come originally from Sri Lanka, and the monoecious biotype which was found in the Cayuga Inlet, is thought to come from Korea. However, Hydrilla was first found in the United States as early as 1950 in Florida. It was brought to the United States for use in aquariums in the early 1950s and was found in canals in Miami and Tampa soon after. The monoecious biotype is often found in cooler climates, while the dioecious biotype is found in warmer, more consistent climates.

Hydrilla might have originally made its way to the Cayuga Inlet in the way it first appeared in Florida, through aquarium dumping. The other likely option is that Hydrilla remnants were attached to a boat or a trailer.

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3 – What is being done to eradicate Hydrilla?

To contain the invasive plant, the city created the Hydrilla Task Force which created The Cayuga Inlet Management Plan. Because the plant was found at an early point, officials hope to be able to completely eradicate it within five to eight years. When the infestation was discovered in 2011, workers administered the herbicide endothall to treat it. In 2012, officials began to use a combination of endothall and fluridone on the Cayuga Inlet. When Hydrilla was discovered to have spread to Fall Creek in 2013, endothall was administered to 22 acres. Hydrilla has also been discovered in the Southeast corner of Cayuga Lake, but so far no herbicide has been used in Cayuga Lake. Instead, it was removed by hand and covered with benthic barriers, which are mats placed on the bottom of a lake to block light and stunt growth.

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4 – How does Hydrilla affect the community?

Because Hydrilla was discovered early, it hasn’t affected the community much besides annual inlet closings for boaters. For 1-2 days a year, boating is restricted and the Cayuga Inlet and Fall Creek close so that herbicides can be administered. Hydrilla can become a very expensive problem if not contained.

Read the latest management plan here.

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5 – What is Hydrilla costing the community?

So far, Hydrilla treatments have cost between $755,000 and $800,000, according to James Balyszak, Hydrilla Program Manager for the Hydrilla Task Force of the Cayuga Lake Watershed. This total includes herbicide treatments, plant monitoring and sampling, water quality sampling, permit applications, education and outreach and in-kind/match contributions. For the coming 2014 year, Balyszak estimates costs to fall somewhere around $300,000 to $350,000. This funding comes from state, federal and local sources including the Fish and Wildlife Service: Aquatic Nuisance Species Grant, New York State Parks, New York State Department of Environmental Conservation and the City of Ithaca.

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6 – This is a lot of text. Can I just watch a video?

You sure can. Here’s one from Owl Gorge Productions:

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Kelsey O'Connor

Kelsey O'Connor is the managing editor for the Ithaca Voice. Questions? Story tips? Contact her at koconnor@ithacavoice.com and follow her on Twitter @bykelseyoconnor.