Fighting Invasive Species with Biocontrol in Carbon County

Since the early 1980s, the Carbon County Weed and Pest District (CCWP) has implemented biocontrol as invasive species management for its integrated weed control program.

Invasive species pose a severe risk to native plants and wildlife throughout Wyoming and Carbon County. They can quickly take over an area, push out naturally occurring plants, decrease habitat and forage for wildlife and livestock, which ruins the environment. 

Many different control options, such as biocontrol, are used to combat these invasive species.

Understanding biocontrol

Biocontrol is the control and reduction of invasive weeds and pests by naturally occurring enemies. Species used for biocontrol are harmless to native species of wildlife and go through rigorous research and approval before being released into an environment.

J Sheehan, assistant supervisor for CCWP, noted educating landowners, government agencies and recreationists about biocontrol is a large part of its success.

“While it isn’t a silver bullet, biocontrol is an effective and viable option for invasive weed management, especially when it’s used with other methods like herbicides,” Sheehan stated. “It takes a lot of time and commitment, but we’ve seen it work throughout the county for many different species.”

CCWP biocontrol methods

Today, CCWP has many successful biocontrol programs using weevils, flies and fungus which target seven different invasive species, including musk thistle, leafy spurge, yellow toadflax, spotted knapweed, Canada thistle, poison hemlock and common mullein.

The first use of biocontrol in Carbon County occurred during an outbreak of musk thistle in the Encampment and Baggs areas in the early 1980s. 

Because of the outbreak’s severity, CCWP, the Wyoming Department of Agriculture and local landowners came together to control the outbreak using herbicides and biocontrol. Two weevils were introduced to fight the invasive weed.

Now, the once out-of-control musk thistle continues to be successfully managed with the weevils and additional herbicide treatments.

“The very first biocontrol we started with is the most successful one,” said Sheehan. “The insects were a perfect match for the climate and elevation in the area. It’s not 100 percent, but it’s in a very manageable situation now where we can control it.”

The Wyoming Weed and Pest Council (WWPC) is comprised of 23 weed and pest districts in the state of Wyoming. The council works closely with the Wyoming Department of Agriculture and the University of Wyoming to keep current with the latest technology and research available in the ongoing management of noxious weeds and pests. The overall mission is to provide unified support and leadership for integrated management of noxious weeds and pests to protect economic and ecological resources in the state.