Tompkins Weekly 05/20/2013

By James A. Balyszak

With the onset of spring and the arrival of warmer weather, residents of Ithaca and the Finger Lakes Region look to the outdoors for recreation and relaxation. This exodus to the outdoors marks a wonderful respite from the clutches of winter, and the beginning of a new season. At the same time, this transition also marks the beginning of a different type of season…Hydrilla Eradication Season!

The Hydrilla Task Force will continue hydrilla eradication efforts in the Cayuga Inlet during the 2013 treatment season (June-November). These on-going efforts, begun in the fall of 2011, will reduce the overall biomass of hydrilla in the inlet (above the sediment), and help to further reduce the tuber population (below the sediment). These tubers pose the greatest risk for the potential spread or re-infestation of hydrilla in the Cayuga Inlet and beyond.

Hydrilla tubers can remain dormant and viable in the soil for 3-6 years, only to give rise to new hydrilla plants when they sprout in the future. Numerous treatment alternatives were examined by the Hydrilla Task Force, with herbicide treatments being the most viable option (in terms of effectiveness, logistical feasibility, and long-term costs). These treatments will use both contact and systemic herbicides to target hydrilla; killing it above the sediment, causing the tuber to expend energy and resources, and preventing the development of new tubers.

The 2012 herbicide treatments were successful, reducing hydrilla biomass by 90-95 percent and reducing tuber density to a tenth of what it was. Although the efforts of the past year were effective, tubers are still present in the inlet, as expected, since herbicides are not effective in killing tubers below the sediment.  Herbicide treatment will continue to be needed until the tubers are eliminated, possibly until 2020.  Sampling and monitoring of the tuber population and any growth of hydrilla will inform if and where herbicide treatment will be used. Long-term sampling and monitoring is expected to extend past 2020 to ensure that all hydrilla is eradicated and has not spread.  In other states, eradication efforts have failed when monitoring or herbicide treatments were stopped too soon.

Hydrilla is often referred to as one of the world’s worst invasive plants. Its ability to spread rapidly through plant fragmentation and turions (buds), and the fact that tubers remain dormant and viable in the soil for years, make eradication challenging. States like Florida, where hydrilla has taken over a majority of the shallow freshwater bodies, spend upwards of $20 million annually to control and manage hydrilla. Eradication is no longer a feasible option for states like Florida where the population is so well established and widespread.

Fortunately, the infestation was caught early on in the invasion of Cayuga Inlet, where the hydrilla population was still low enough for eradication to be a feasible option. If hydrilla was allowed to grow unchecked it would quickly dominate the inlet and spread rapidly into shallow areas of Cayuga Lake. From there it would not take long for it to spread to neighboring Finger Lakes, the Erie Canal, and the Great Lakes. Once established, hydrilla would cause a substantial loss of native aquatic habitat; displace native species; negatively affect boating, fishing, and recreation; reduce income from tourism and lakeshore properties; and diminish the flood control properties of the inlet. The consequences of not acting swiftly to eradicate hydrilla in the inlet far outweigh the costs of implementing a 5-8 year eradication plan.  Because the predictions are so dire, the Hydrilla Task Force formed to address the hydrilla infestation, which includes creating the Cayuga Inlet Management Plan. Local, state, and national stakeholders and experts carefully considered all possible management options.  Selection of the strategies used in 2011, 2012, and suggested for 2013 and beyond, was based on effectiveness, feasibility, and benefits to the environment and community. The current eradication plan offers the best possibility of success and long-term benefits.

If you would like more information about hydrilla and local eradication efforts, please visit our website  StopHydrilla.org  and like us on Facebook at “Stophydrilla.org” and on Twitter @Stophydrilla.

Questions, comments or concerns can be directed to the Hydrilla Program Manager, James A. Balyszak, 1771 Hanshaw Road, Ithaca, NY 14850, 607-257-2340 or stophydrilla@gmail.com