BELMONT, N.H. (AP) – A weevil that has a taste for Eurasian milfoil doesn’t like the species of the invasive aquatic plant found in Maine and New Hampshire lakes.

“While the weevil likes to eat Eurasian milfoil, we found it would rather die than eat variable milfoil, the type of milfoil commonly found in lakes and ponds throughout Maine and New Hampshire,” said Jody Connor from the New Hampshire Department of Environmental Services.

Some towns had hoped the weevil that feeds exclusively on milfoil would help them combat the lake weed without having to resort to herbicides.

The milfoil weevil, which is a tiny beetle the size of a sesame seed, is native to North America and has been found in some New England states, including Vermont.

Scientists believe the weevil originally fed on native Northern milfoil but switched to Eurasian milfoil in the 1940s. When exposed to Eurasian milfoil, the weevil eats it, causing the plant to lose buoyancy and collapse.

But state officials say lakes in Maine and New Hampshire have a different water chemistry than lakes in Vermont.

The low calcium and high acidity in Maine and New Hampshire water prevents Eurasian milfoil from taking hold. Instead, it’s variable milfoil that’s the bigger problem in Maine and New Hampshire lakes and ponds.

The weevil is attracted to Eurasian milfoil by two chemicals released by the plant: uracil and glycerol. Variable milfoil lacks them. Thus, the picky weevil chooses death over such a bland dish, Connor said.

Connor noted that the weevil doesn’t eliminate milfoil even where its introduction has helped control the weed.

“The weevil doesn’t kill milfoil, it merely tones it down, but the plant grows back because it doesn’t take out the roots,” Connor said.

The best way to manage the weed is to use several methods, including herbicides and pulling it out by hand, Connor said.

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Information from: Citizen, http://www.fosters.com/citizen

AP-ES-11-05-06 1301EST

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