WEST MILFORD An aggressive aquatic invader from Eurasia that once pestered aquarium-keepers is a huge nuisance in America including Sussex County and its surrounding areas. In West Milford, it’s caused locals to call their two-state lake “Greenweed,” and just outside of Newton, Little Swartswood Lake has by some been called Little Swartsweed. Eurasian Milfoil is the exotic-sounding name of the slimy, filmy, livid green gunk floating on area lakes. Eurasian watermilfoil (Myriophyllum spicatum L.) is an exotic aquatic plant that was introduced to North America sometime in the late 1800s and was then found in a pond in Washington, DC, in the early 1940s. A boating boom in the 1970s stimulated its growth because it tends to be spread through ballast water. It was ballast water on ships that brought many similar species from continent to continent in the first place. Fishermen may also unwittingly introduce plant fragments to clean lakes from infested ones. The milfoil grows rapidly and tends to form a dense canopy on the water surface, which often interferes with recreation, inhibits water flow, and impedes boating. Bob Cartica, the Administrator in the Office of Natural Lands Management in the Division of Parks and Forestry said. The New Jersey Department of Environmental Protection is addressing the milfoil issue in several different ways. Cartica said milfoil has become a huge problem. “This species is part of a much larger problem involving species throughout New Jersey. The Eurasian Milfoil is a very rooted, perennial plant that comes back year after year. It’s a huge problem in low energy areas like lakes and non-rushing streams.” Cartica added, “It’s being addressed in different ways around the state depending on funding, the area’s method of choice and the severity of the milfoil.” Herbicides or harvesting Currently, herbicides or mechanical harvesting are most often used to control water milfoil infestations. As is the case with terrestrial weeds, control often must be done annually and sometimes more than once per season, but these controls can be expensive. There is also concern that the methods may harm certain non-target organisms, so exploring other approaches is desirable. On Lake Hopatcong, the state’s largest lake, harvesters clear the weed as well as others below the surface. The Lake Hopatcong Commission learned unseasonably mild weather the past two winters which allows weed growth to continue during the cold months -- has created milfoil and other weed problems for most local lakes. Though the Environmental Trustee of the Paulinskill Lake Association, in Stillwater, Cindy Tracey, was unable to speak about Paulinskill Lake because of “a board policy forbidding giving out information concerning the lake management for newspaper articles,” she did report in a PLA newsletter that the lake was lowered last winter to “freeze the bottom to control the milfoil growth.” The Aug. 23 newsletter stated, “We were successful this [past] winter with freezing the milfoil. There is still a small pocket of growth in the lake. We need to be careful when we put our boats into other bodies of water. The bottom, trailer, motor and wells need to be completely free of any milfoil fragments or any other weeds before launching into the Pulinskill. It takes just a fragment to sprout and cause a weed problem. Fishermen also need to clean their tackle to prevent weeds from entering our lake.” Weevils to the rescue In addition to harvesting, Swartswood State Park employs a tiny ally, a milfoil weevil. It is a milfoil (Myriophyllum spp.) specialist, meaning that it feeds and develops only on plants in this genus. The weevil completes all life stages fully submerged and the larvae are stem miners. Specialist herbivores are very rare among aquatic insects so the milfoil weevil has shown the most promise as a method. The weevil has been used both in Big Swartswood Lake and Little Swartswood Lake. The weevil was introduced in 1999 and then again in 2000. “Since it takes several years to determine their effectiveness, we’ll be doing follow up next year to determine,” Cartica said.