Eurasian milfoil (Myriophyllum spicatum) is a feathery-looking underwater plant that has become a major nuisance in waterways in the United States. Introduced into the country over 70 years ago as an ornamental tank plant by the aquarium industry, it has since spread to the East Coast from Vermont to Florida and grows as far west as Wisconsin and Texas. It is also found in California. It is particularly abundant in the Chesapeake Bay, the Potomac River, and in some Tennessee Valley reservoirs.

Eurasian milfoil is able to tolerate a wide range of salinity in water and grows well in inland fresh waters as well as in brackish coastal waters. The branched stems grow from 1–10 ft (0.3–3 m) in length and are upright when young, becoming horizontal as they get older. Although most of the plant is underwater, the tips of the stems often project out at the surface...