UNH Team Searches For a Milfoil Adversary

Article courtesy of Lake Wentworth Association

Concord — August 22, 2005 — A new project directed by the University of New Hampshire is attempting to determine whether biological agents found in the upper Midwest may be of some help in controlling variable milfoil in New Hampshire.

The effort, funded with $225,000 from the National Oceanic and Atmospheric Administration (NOAA) and the US Environmental Protection Agency, brings together Jeff Schloss, director of the Center for Freshwater Biology at UNH, with Dr. Garrett Crow, a professor of Botany at the school, and researchers Eyualem Abebe and Scott Garnett of the Hubbard Center for Genome Studies.

The UNH project is one of seven in the state intended to evaluate milfoil control and funded with a $1 million grant obtained by Senator Judd Gregg. The money is being managed by the New Hampshire Department of Environmental Services.

The university project is the only one that will study the use of biological agents – in this case, round worms or nematodes – to manage milfoil. In addition to Wentworth, the study will include five other lakes in New Hampshire and an equal number in Wisconsin and perhaps Minnesota.

In the latter two states, variable milfoil is a native species that does not grow out of control as it does here in New Hampshire. The UNH researchers are attempting to determine whether insects found in the upper Midwest may play a role in keeping the milfoil there in check. In visits to Wisconsin and Minnesota, Schloss and the others are hoping to collect nematode specimens and bring them back to the laboratory in New Hampshire, where their effect on milfoil can be studied in a controlled environment.

If the nematodes prove effective in managing milfoil, they might be used – possibly in combination with other controls, such as hand pulling and herbicides – to keep milfoil in check where it has gained a foothold, such as Wentworth and Crescent Lake.

The Center for Freshwater Biology, which Schloss directs, provides research and consulting services to lake associations and other organizations in New Hampshire. It operates the Lakes Lay Monitoring Program, which uses volunteers to monitor water quality in lakes across the state. The Lake Wentworth Association has participated in the program for over 15 years.

Crow is the author of a definitive handbook on freshwater plants and serves as the group’s plant identification expert. Nothing would torpedo the project faster than misidentifying the plants species under study, he noted.

The Hubbard Center for Genome Studies, where Abebe and Scott work, is devoted to understanding the structure and function of genomes and has a particularly strong focus on marine and aquatic organisms.

On a recent morning, the foursome loaded their equipment onto a pontoon boat at Hersey Shore and headed towards Brewster Heath. Once there, it took little time to find a large patch of milfoil near the center of the channel through which Heath Brook enters Lake Wentworth. Anchored among the weeds, they lowered a video camera on a boom into the water and recorded the dense growth. Schloss observed that milfoil out-competes native species by growing rapidly towards the surface and then folding across the surface, where it acts as a light-blocking canopy.

Schloss and Abebe then assembled a large brass tube and a capping device that they drove into the muddy bottom of Brewster Heath. The core sample was then retrieved and deposited into carefully labeled containers for later study. The researchers were surprised when the samples appeared to show sand underlying the layer of mud that coats the floor of the Heath. Nematodes, it turns out, like sandy environments.

Finally, Schloss and Crow donned masks and snorkels and dropped into the cool waters of the brook, gliding into the milfoil bed and selecting samples for later examination.

The researchers will now move on to other New Hampshire lakes, yet to be selected, and repeat the sampling process. They will then travel to the Midwest to conduct like studies, attempting to discern the natural conditions that keep Wisconsin and Minnesota milfoil in check.

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