MONCTON - Scientists have discovered the purple loosestrife's achille's heel - a tiny beetle that likes to snack on the wild weed.

Loosestrife is a wetland's nightmare, it spreads uncontrollably and has tremendous flower power. Once established in a marsh, it threatens all other plant life. "It has become a real problem in that it has invaded wetlands and by doing so it can actually outcompete native plant species," says John Wile, of Ducks Unlimited Canada.

The purple loosestrife kills biodiversity and the animal life that depends on it. The plant has overtaken wetlands in southern Ontario, Quebec and its making inroads in the Maritimes.

Wile is trying to slow this seemingly unstoppable plant. All hopes rest on a tiny bug, the Galerucella beetle, that likes to devour the loosestrife. Ducks Unlimited began releasing the insects in 1996 and since then, more than 65,000 have been set loose on the loosestrife.

More recently, they released larvae instead of adults beetles, and scientists are seeing the impact. "This is what we've been waiting for for five years, some real plant damage as a result of the insect activity," he says. There's actually a larvae feeding this plant right now, as well as others. And they've stressed this plant considerably. You can tell all the green material has been destroyed."

Students from the Tantramar Wetlands Centre are helping Ducks Unlimited quantify the impact of the Galerucella beetle by recording egg mass and counting larvae and adults beetles. "With the information we collect we'll be able to figure out what time is ideal to move larvae from one site to another and release it to aid with problems of purple loosestrife in other areas," says Megan Mitton, of the Tantramar Wetlands Centre.

The purple loosestrife has been around for a long time and has a tremendous seed bed in area wetlands. So, Wile cautions that even with the Galerucella beetle there's a long battle ahead.