Regional Projects Include:

FL-LOWPA/USGS GIS Metadata Project
Assessing the Potential for Bio-Control of Eurasian Watermilfoil in New York State Lakes
State of New York Lake Ontario Basin Project

Local, Federal and State Data Sources for Watershed Planning and Analysis.

Milfoil Clogs New York State Waters

Eurasian watermilfoil (Myriophyllum spicatum) is the predominant submersed aquatic plant nuisance found in ponds and lakes throughout New York State. This aggressive weed grows rapidly to the surface forming a dense canopy that clogs waterways. The canopy blocks sunlight from reaching desirable native plants that grow at a slower rate, and lose their struggle with Eurasian watermilfoil.

Failure of Mechanical Harvesting and Chemical Herbicides as Long-Term Controls Mechanical harvesting and chemical herbicides are management strategies long used in New York State to control excessive aquatic plant growth. These two methods yield little long-term success in controlling watermilfoil growth. Harvesting and chemical controls provide only annual relief at a cost of millions of dollars each year in New York State and throughout North America.

Aquatic Insects Preferentially Eat Milfoil in New York Lakes
In 1991, aquatic moth caterpillars were observed eating and causing severe damage to Eurasian. The insect is the European aquatic moth, an exotic species. It is not known how long before 1991 the aquatic moth entered Cayuga lake, but biomass sampling by Cornell University Section of Ecology of Systematics from 1987-1991 showed that large areas of milfoil failed to flower at the surface. This lack of flowering and inability of milfoil to reach the water surface to form a canopy often indicates insect feeding on the growing tip of milfoil. During this time, desirable native submersed plant species took advantage of the damaged, "chewed up," milfoil and now dominate Cayuga Lake's aquatic plant community. This very diverse, stable, and healthy aquatic plant community supports increased aesthetic, recreational, and fishery uses of Cayuga Lake.

Fig. 1 Northwest and Southwest Study Areas of Cayuga Lake showing decline of Eurasian watermilfoil with return of native plants.

Survey Finds Aquatic Insects Feeding on Milfoil in Several New York State Lakes
FL-LOWPA has cooperated with Cornell University to survey area lakes and ponds for the presence of the European aquatic moth and another invertebrate, an aquatic weevil (Euhrychiopsis lecontei), which also feeds on macrophytes. Robert Johnson or Cornell's Experimental Ponds Program has directed these surveys. Qualitative and quantitative data about the presence of these insects in area lakes were recorded (Fig. 2). Lakes in counties outside of FL-LOWPA were surveyed during this period as well. The surveys report the caterpillar of the aquatic moth, Acentria ephemerella, eating milfoil in 31 of 33 New York lakes and the aquatic weevil, Euhrychiopsis lecontei eating milfoil in all surveyed lakes. The surveys further show some lakes, or areas of a lake, to have very large numbers of these insects present while other lakes have very few. Future research will try to answer why some lakes support greater numbers of these insect herbivores than others.

Recording of Aquatic Moth (Acentria ephemerella) and
Aquatic Weevil (Euhrychiopsis lecontei) in New York Lakes 1995 - 1997

Fig. 2 Samples collected from 42 locations in 33 lakes in 19 counties. The table shows herbivore presence with 'y' for yes or 'n' for not found. Lakes marked with an * were not part of quantitative field surveys and have a '?' entered if no herbivore was observed. A 'n' means no herbivore was recorded as being present in the lake from our sampling, but it may still be present. We sampled these lakes at least once from 1995 to 1997.

Can Insects Limit the Growth of Milfoil in New York State?
These insects are already causing severe damage to milfoil in many New York Lakes, with the aquatic moth associated with declines of milfoil and recovery of native plants in a few lakes. A decline is defined as a decrease in milfoil growth over a number of growing seasons, and is different from a "crash" of milfoil plants within a season. The aquatic weevil is found causing damage to milfoil in all lakes surveyed, but milfoil declines associated with the weevil have not been observed in New York. Monitoring of New York lakes for long-term declines associated with these insect herbivores will continue. Paradoxically, current methods used to control the growth of milfoil in New York can be detrimental to the survival and reproduction of these beneficial insects, resulting in an increase or continuation of milfoil growth. Individuals and organizations responsible for aquatic plant management need information on these dynamics and on-going research.

For more information, contact:

Robert L. Johnson Manager of the Cornell Pond Facility Section of Ecology and Systematics 150 Corson Hall Cornell University Ithaca, NY 14853

Phone: Fax: E-mail:

607-257-2064 607-255-8088 rlj5@cornell.edu

The WRB initiated the State of the Basin project to:

• Assess water quality status in the region.
• Identify approaches to water quality problems, and describe especially successful local efforts to facilitate the transfer of good ideas in the basin.
• Assess the degree of congruence between water quality problems as identified through state data sources and local priorities and grassroots efforts to mitigate nonpoint sources of pollution within subbasins.
• Recognize the work accomplished by other organizations involved in water quality, and identify potential areas for collaboration.
• Clarify and set organizational goals for FL-LOWPA.

A complete copy of State of the New York Lake Ontario Basin Project is available.

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