DUBLIN -- The Dublin Garden Club and Dublin Conservation Commission are winning the war against an invasive plant growing in town — thanks to an army of thousands of small brown beetles.

In August members of Conservation Commission released 3,000 Galerucella beetles into a grove of the invasive purple loosestrife growing at the edge of Mud Pond on Route 137.

It's been a joint effort between the organizations, which initially got a permit from the state Department of Agriculture to release the beetles in wetlands.

“We did more this year than ever before, but we have released them since the summer at 2008,” said garden club and conservation commission member Louisa Birch. “At the beginning it didn't seem to be doing a lot, but this summer, this year we did see a real difference.”

The purple loosestrife is a flowering plant 1 to 1.5 meters tall that was brought to North America from Great Britain, central and southern Europe, Russia, Japan, China, southeast Asia and northern India for its beauty.

“It's very pretty. It was brought here as an ornamental,” Birch said.

Unfortunately the plant has no natural enemies in North America.

“What happens is it comes and it takes over and it crowds out the other plants,” Birch said, impacting not only plant life, but wildlife. “Many of the insects, particularly butterflies, only put their larvae on native plants.”

And the purple loosestrife thrives in wetlands, crowding out plants that may serve as habitat for animals that live in the water.

Galerucella beetles also hail from Europe and Asia, where they keep purple loosestrife in check by munching on the leaves, flowers and roots.

After researchers found purple loosestrife is the only food the beetles eat, both the United States and Canada began releasing the bugs on the plants.

“In 1976, the USDA got permission to allow these beetles to be in this country,” Birch said.

The beetles cause no harm to other plants or animals, Birch said, and the adult insects and their larvae eventually kill the plant.

Over the past four summers thousands of beetles have been released in the wetlands along Route 101 and Route 137 and a small growth of the plant at the cemetery was cut, which can be done effectively to small patches, Birch said.

“They reproduce and they sleep in the mud over the winter so they'll come back next spring,” Birch said.

Finally this year the purple loosestrife invasion seems to be shrinking and native species such as cattails, grasses and sedges, which offer habitat and food to native wildlife and insects, are returning and are no longer being crowded out.

Birch said it was expected the bugs would need a few years to have an impact on the purple loosestrife. “It takes three to four year before it works.”

The garden club and conservation commission also work together to eradicate other invasive plants from town; milfoil was successfully removed from Dublin Lake a few years ago and the organizations continue to battle Japanese Knotweed.

mpierce@newstote.com