Eating What You Love: The Credo for Mile-a-Minute Weevils

Tiny Mile-a-Minute weevils on one of the fast-growing vines behind North Haven Village Hall. Peter Boody photo

How hard can it be to do a good job if all you have to do is eat what you love?

Mile-a-Minute weevils live to eat Mile-a-Minute weed, an especially aggressive invasive species from Asia that is popping up all over the region.

The Village of North Haven last year bought 500 of them at $1 each from an agricultural lab in New Jersey to suppress a patch of the fast-growing vine behind Village Hall. Like the weed they love to eat, the weevils are transplants from Asia.

Village Clerk-Treasurer Eileen Tuohy reported at the August 6 North Haven Village Board meeting that they did such a good job, the village this year bought 500 more, putting them to work on another patch nearby.

The hope is, she later explained in an interview, they will multiply and create a counterforce to a species that otherwise could smother and kill every growing thing its path.

The village building inspector, George Butts, is the one who takes the weevils, which are delivered in a coffee-cup-like container, and puts them out on the edge of the Stock Farm Preserve abutting the backyard of village hall.

This year, “I couldn’t find a piece of Mile-a-Minute weed” in the 50-by-100 foot area in which he released the weevils last year, he said in an interview. “Everything in the area was gone.”

The additional weevils he released in June on another patch of weeds, further to the north, appear to be doing well, with the triangular leaves of the thorny vine full of the “buckshot” holes that show the weevils are feeding.

“They’re doing their due diligence,” Mr. Butts said. “If I can see it working here, I could clear the whole village property. That would be great.” Spending $500 a year to stop the infestation, he added, is a bargain — especially if their population takes off, making further purchases unnecessary.

North Haven is a regional hotspot for the invasive species, according to Laura Smith, principal environmental analyst for the Southampton Town Community Preservation Fund (CPF). She has been coordinating the town’s efforts going back 13 years to control Mile-a-Minute weed on about 20 parcels of town-owned preserved open space.

There are many invasive plants gobbling up territory in the region, she said — Japanese stilt grass, caper spurge, garlic mustard and mugwort, to name a few — but Mile-a-Minute weed is the fastest grower of them all and it can thrive in almost any kind of habitat locally.

“I see it everywhere,” Ms. Smith said of Mile-a-Minute weed. She believes it is spread mainly by nursery stock, the root balls of which contain Mile-a-Minute seeds.

A particularly bad outbreak can be found off Deerfield Road in Water Mill where the road crosses the power-line right-of-way, Ms. Smith said. The weed is thriving on privately owned open space that was created through a subdivision plan.

The CPF department can only spend money and deploy workers to deal with outbreaks on public land. It uses an organic, salt-based herbicide called Adios and hand-pulling by the roots, which Ms. Smith said is the most effective way to control the weed. It has to be done before the vine goes to seed, she noted, otherwise hand-pulling just drops seeds onto the soil to germinate.

Ms. Smith said the town doesn’t use Mile-a-Minute weevils “because they are expensive and they take a long time to be effective.” The town is “trying to tackle the problem more quickly than that,” she explained.

When the annual produces seeds during the season can vary, depending on temperature, habitat and sun exposure, Ms. Smith said, but late July is often mentioned in articles on Mile-a-Minute eradication as the deadline for hand-pulling.

Pulling out the weed by the roots is quite easy and highly effective but it can have a countereffect: it can disturb the soil, providing air and light for seeds that had been buried, allowing them to germinate.

Dr. Andy Senesac, a weed science specialist with Cornell Cooperative Extension of Suffolk County, has done some experimental deployments of Mile-a-Minute weevils. He said in an email this week that they appear to thrive in sunny areas and so may not be effective on Mile-a-Minute infestations that are in shady locations.