Beetles Released To Fight Invasive Plant

By Kendra Bobowick

He held the container casually as if he might sip coffee from it, or set it down and remove the lid to let it cool. Todd Mervosh, weed scientist with Connecticut’s Experiment Station, stood beside his van at Sticks and Stones Farm along Huntingtown Road July 9 and peered into his cup: inside were 500 vine-eating beetles called weevils that, along with a second group of 500, would be released minutes later with a single-minded objective: eliminate the invasive mile-a-minute vine.

“The mile-a-minute has been going on for years,” said farm owner Tim Currier. “It’s certainly something I don’t want.” Connecticut is using the weevils for the first time to combat the pervasive weed. Newtown is one of only a handful of state municipalities where the weevils will be released and monitored. “It’s a limited start, but we’re happy about it,” said Connecticut Senior Extension Educator Donna Ellis in late June.

Mr Mervosh, Ms Ellis, and Ann Astarita with the Land Use Agency, among others, met at the farm and soon worked a path between shoulder-height weeds and invasives growing along the meandering Pootatuck River that slipped beneath the road and spilled through a field. With help from UConn plant coordinator Logan Senack, Mad Gardener Invasive Species Task Force member Kathleen Nelson, project intern Eric Andruk, and Mr Mervosh’s assistant Zack Donais, the group stepped through mud and undergrowth, and found clusters of mile-a-minute vines. Removing the container lids and tipping the cups toward the vine’s broad, triangular leaves and barbed stems, Ms Ellis and Mr Mervosh gently brushed the miniature insects onto the foliage.

Inclined to scurry to the plant’s undersides, 1,000 weevils quickly disappeared.

Ms Ellis explained that the weevils bore into the stems and lay eggs that feed on the plant. The beetles can turn an orange shade after ingesting mile-a-minute, and Ms Astarita will likely see holes in the mile-a-minute leaves when she returns in several weeks to see how the project is working. Ms Ellis hopes that the insects will carry out “two or three generations, then winter over in the soil.” Will they survive? “We’ll find out,” she said. “There could be hundreds more by fall.” Mr Senack noted, “This is the farthest north they have been released in the United States.” What eats the weevil? That answer also remains to be seen, Ms Ellis admitted.

Once one patch of mile-a-minute is exhausted, the weevils hopefully will “move on and find another pocket,” Ms Ellis said. Mr Mervosh guessed “they might nibble” on another species, but should not have a large impact. On their way to the invasives site, Ms Ellis found a good omen. Signs that another beetle that had been introduced to combat the purple loosestrife were evident. She had begun that experiment in the mid-1990s.

As Ms Astarita made notes on a clipboard, Mr Mervosh and Ms Ellis shook loose the last weevil. “OK, now they do their thing,” Mr Mervosh said.