The small seed-like insects in a modified plastic take-out container cup don’t look much like warriors, but they are.
The weevils are being enlisted in the fight against the ultra-fast growing and prickly mile-a-minute weed that has been discovered in seven counties in the state — Alleghany, Gates, Guilford, Rockingham, Pasquotank, Perquimans and Yancey.
The vine looks delicate, with triangular leaves, but prickly spines running along the entire vine easily ensnare passersby. The weed name might be a little of an exaggeration, the plant actually grows about six inches a day. The annual plant seeds prolifically and the seeds can stay viable for around six years, adding to its ability to spread rapidly via birds and deer.
As the vine grows, it will overtake neighboring plants and bushes, covering them. In August, it is more noticeable because of the blue berries it produces.
“By the time people notice the weed, it is already well-established,” said Kathy Kidd, the biological control administrator for NCDA&CS.
Kidd and Rebecca Norris, a research specialist, recently released some 5,000 weevils at sites in Alleghany, Guilford, Rockingham, Pasquotank and Yancey counties. The Guilford County location has been a fairly recent discovery made by butterfly enthusiasts looking to gather milkweed seeds to boost plantings that are attractive to Monarch butterflies. Fortunately, they spotted the weed and passed that information along. Department staff inspected the site, located along power line right-of-ways, and confirmed the presence of this non-native invasive plant.
The weevils come from the N.J. Department of Agriculture, which has been using the insects to combat the weed since around 2005. Weevils have been released for three years in Alleghany County, where the insect has been found to overwinter well. The weevils feed on the plant, burrowing into the plant stem. As they feed, they halt the growth of the vine, reducing the height of the plant and limiting seed production. The insects reproduce every 30 days and they only feed on the mile-a-minute vine.
Kidd and Norris will check back on the weevils in about a month. They will be looking in the same areas to see if they still find mile-a-minute vines, but also will be looking at the color of the weevils they find. Black weevils indicate a new generation of insects, while orange weevils indicate ones that were released. If all goes well, they will continue to find weevils that are thriving and well-fed, Kidd said.
Anyone with questions can contact Kidd at 919-233 – 8214.