Weevils get to work on weeds

PLEASANT GROVE — Hairy weevils are scrambling over each other, exploring the arms of a spiny yellow starthistle, stretching their legs after a cramped, overnight Fed Ex trip from Montana.

"They're probably sick of being in that container," says Marcy DeMillion, natural resource staff officer for the Pleasant Grove Ranger District.

The early morning release of the weevils Wednesday was the first time the U.S. Forest Service has released biocontrol agents to help tackle the weed population in the Uinta National Forest — and DeMillion is fascinated by the creatures.

"Those two are trying to figure something out over there, and those guys are getting lost," DeMillion says as she watches the long-nosed insects crawl on the thorny plant. "Wow, they're just zooming along."

Originally, DeMillion planned to target leafy spurge with biocontrol agents this summer, but she changed her mind after re-evaluating her district's weed problem.

Yellow starthistle is a poisonous plant that outnumbers leafy spurge and is resistant to chemical sprays. DeMillion said her ranger district recently sprayed a large amount of leafy spurge and the chemical treatment has already been highly effective.

"We don't want to release bugs on an area that we just sprayed," DeMillion said.

To protect the some 200 weevils released Wednesday, DeMillion cordoned off an isolated, 40-square-foot area in the hills above Pleasant Grove. The area is peppered with yellow starthistle, but it won't be sprayed or the bugs could die.

The weevils will live as long as the yellow starthistle does, but when the non-native plant is eradicated, the insects will die with the loss of food source. DeMillion says she plans to release 500 additional bugs to the same area early next week. The bugs will be closely observed to see if they have any effect on the noxious weed.

Yellow starthistle originates in Europe, and the United States Department of Agriculture estimates the weed came to America — without its natural predators, such as the hairy weevil — in the 1800s.

The thorny plant is highly invasive and as it spreads, it chokes out the area's natural flora and becomes more difficult for the Forest Service to manage.