Lake Ouachita vegetation is being addressed by the U.S. Army Corps of Engineers, Arkansas Game and Fish Commission,
and the Lake Ouachita Association to control Hydrilla
and Eurasian Watermilfoil.
The goal of the project is to contain and reduce the vegetation, not eradication,
since the presence of aquatic vegetation in moderate amounts is beneficial to the lake's
fishery, Wooldridge said.
Satellite imagery by the U.S. Army Corps of Engineers shows the lake
contains 10,000 acres of vegetation, according to Richard Stokes, Lake
Ouachita project manager. The goal of the project is to reduce the
coverage by 2,000 acres. We will concentrate on high recreational use areas,
such as swimming beaches, around marinas and popular boating areas. Areas of
the lake containing good fishery habitat will not be treated, Stokes added.
The C.O.E. is treating 13 areas with
Pakistani flies a tiny fly that resembles a gnat in size and hops along
the water surface rather than flying. The Corps of
Engineers will inoculate 13 selected areas of Lake Ouachita with
the fly , whose larvae feed exclusively on hydrilla. The Larvae of the fly
will kill the upper three feet of the plants. The Pakistani hydrilla
leaf-mining fly's larvae (hydrellia pakistanae) burrow into the leaves of
the plant. Each larva can destroy nine to 12 leaves during its feeding
The flies will take several years to become noticeably effective.
Other Biological Control of Invasive Species. University of Florida - Center for Aquatic and Invasive Plants.
Lake Ouachita Weed Identification
Hydrilla Verticellata, commonly referred to as Hydrilla is a
very invasive submersed freshwater herb.
It was originally sold
as an aquarium plant. It forms very dense strands growing from
the bottom of the water and sprawling across the surface.
Although it is an excellent source of food for waterfowl, it can
be a serious threat to freshwater habitats and a nuisance to
Hydrilla reproduces by fragmentation.
It does not form any
Even small pieces stuck on boat propellers or in
bait pails contribute to the easy spread of Hydrilla to
other areas and waterways.
Will grow in 30 feet of water.
produces large strands of plants in just a few months through
its efficient use of low light levels and available nutrients.
Green, freshwater herb
Submersed plant with long slender stems
2 to 8 small, spear-like leaves per whorl spread across the
The leaf has a sawtooth edge and small spines on the underside
that are rough to the touch
Grows in as little as a few inches of water or in more than 30
feet of water
Eurasian Watermilfoil (Myriophyllum Spicatum) is native
to Europe, Asia and northern Africa. It was introduced to the
United States many years ago in the 1940's.
Eurasian Milfoil is
an underwater plant and bears only a slight difference from US
native Milfoil. Because it is an attractive plant, it was once
commonly sold as an aquarium plant.
The Eurasian Milfoil has
12-21 pairs of leaflets leaf and the native northern Milfoil
only has 7-11 pairs of leaflets
Milfoil grows best in fertile, inorganic sediments. It prefers
very active lake beds which receive nitrogen and
phosphorous-laden runoff. Because of the poor seed germination,
it reproduces by fragmentation.
It produces fragments during the
summer after fruiting once or twice. The shoots get carried away
by currents or boaters. Because of its ability to spread
rapidly, it often blocks out sunlight for plants native to the
lakes. The dense groups can also block out larger fish,
therefore disrupting the predator-prey relationship. Many
waterways become congested due to these dense groups as well.
Reddish-brown plant stem that thickens below the water
and curves to lie parallel with the water surface
Submersed feathery leaves
Tiny 4 part flowers stick out 2 -4 inches above the water
The flowers can be four petaled or without any petals
The fruit is contained in a hard capsule with 4 seeds in it
The Desirable Plant
Coontail (Ceratophyllum demersum) is a free-floating
submersed plant without any roots.
desirable when managing for waterfowl and fisheries. The leaves and seeds of
coontail are eaten by waterfowl, and it provides a home for a variety of aquatic
These insects then serve as food for many species of fish and
Coontail also provides cover for small fish, which is important in relatively
Coontail draws its nutrients from the water
directly rather than from sediment like most rooted aquatic
It can survive in cool waters and low light. During the
winter months, it can live under the ice as an evergreen plant and
resumes rapid growth in the spring.
Dark green forking leaves, up to 1 2 inches in length
arranged in whorls on the stem
Submersed plant without roots
Plants may be bushy or very long and sparse
Feathery leaves on the stem resemble a raccoons tail. The stems
can be 1 to 2 feet in length.
The leaf has small teeth on the midribs which make it rough to
It has very small flowers which are rarely seen