Video: Beetles used to battle loosestrife on Neponset

Jeff Mucciarone

Clouds of beetles swarmed over a wetland meadow at Brookwood Community Farm last Thursday.

The tiny, winged creatures latched onto clusters of plants and began to munch away on the plants’ leaves. In some spots, the beetles nearly covered the purple flowers adorning the tops of the thickly spread greenery.

The beetles were taking over—and that’s exactly what the Neponset River Watershed Association is hoping for.

Purple loosestrife is engulfing big sections of the Neponset River watershed. But the Canton-based watershed association, the state Department of Conservation and Recreation and the Wetlands Restoration Program are fighting back—with beetles.

For the second time this summer, officials and volunteers released thousands of Galerucella beetles, which exclusively eat purple loosestrife, a particularly invasive plant species with purple flowers that form a cone-like shape, somewhat resembling lilac.

And while the plants might look attractive, they are forcing out native species, such as spiraea, cattails,aster or elderberry that have longed thrived in the same wetland meadows the loosestrife is trying hard to take command over.

“Once purple loosestrife establishes a foothold in a local wetland, it spreads until it dominates and essentially crowds out the native wetland vegetation relied upon by native wildlife,” according to the watershed association’s Web site,

The watershed association, which works to preserve and protect all 14 towns and 120 square miles within the Neponset River watershed, released 5,000 beetles Thursday at Brookwood Farm in Milton and Canton and another 5,000 in the Fowl Meadow on sites in Milton and Readville. Both locations are within the Blue Hills Reservation. With endangered species and threatened species living within the Fowl Meadow, officials are hopeful the beetles have their appetites this summer.

Eliminating purple loosestrife is part of the state department of conservation and recreation’s statewide program to restore wetlands. For five years, officials and volunteers will release beetles and monitor sites in the Neponset River watershed to control and hopefully eradicate purple loosestrife, said watershed association Outreach Director and Restoration Manager Carly Rocklen.

As they fly up from their buckets, some beetles immediately grab onto plants, while others fly a little way before nestling down to feast.

The beetles are mailed from a beetle harvester in New Jersey in buckets. The packages come with an ice pack to keep the beetles cool during the travel, Rocklen said.

Galerucella beetles have been studied since 1986 to make sure releasing them to feed on invasive species isn’t creating further environmental issues. In some studies, the beetles have reduced purple loosestrife by 90 percent, according to the state’s project summary.

Several months ago, members of the watershed association and the department of conservation and recreation, walked through the sites and marked especially bad infestations. They also kept an eye open for hidden patches, Rocklen said.

Members try to release beetles inside healthier plants. The beetles themselves leave behind holes on the plants’ leaves, but it’s the beetles’ larvae that actually wreak the most damage, Rocklen said.

“They really strip the leaf from top to bottom,” Rocklen said of the larvae. “They need purple loosestrife to complete their life cycle.”

Officials have determined study plots in the two sites. As they release beetles—which they’ll do just about every Thursday this summer—members check to see how the different study plots are doing. In some sites, the plants are browned and chewed-up. Beetles travel several miles to find purple loosestrife and most of the damage so far this year has come from migrating beetles, Rocklen said.

Regardless of where the beetles are coming from, seeing chewed-up plants is promising.