Colorado's Yampa River Leafy Spurge Project--which releases Aphthona beetles to control invasive spurges--has remaining US$337,196 IRA grant frozen; without funds for releases through 2030, efforts to contain rapidly spreading spurge face major setbacks

May 1, 2025 (The Colorado Sun) –

In 2015 a group of volunteer biologists, retired ecologists, ranchers, environmentalists and generally concerned citizens came together to contain a flowery, green-and-yellow plant called leafy spurge. They called themselves the Yampa River Leafy Spurge Project .

Spurges are an invasive plant species that were introduced to the Yampa watershed just west of Hayden about 40 years ago. In the decades since, the spurges, which were once concentrated along a 15-mile stretch of river, have gotten way too comfortable, elbowing out native species and leaking a noxious, milky discharge that irritates cattle and degrades the quality of hay.

The group made steady progress over a decade of work, but the sudden federal funding freeze in February threatens to undo their efforts.

After a flood year in 2011, the invasive species made its way across the flood plain, exacerbating the spread of the spurges. The effect of the flood spurred the formation of the grassroots group in 2015.

Since then, a coalition of local, state and federal agencies, along with the nonprofit group Friends of the Yampa and private landowners have focused on knocking the spurges back to their earlier numbers — if not eradicating them entirely.

They take annual volunteer trips to collect flea beetles from the genus Aphthona, which feed on the leafy spurge roots.

In 2019, the group collected 7,300 beetles and released them in the Yampa River State Wildlife Area . In 2020, they collected more than 23,000 beetles in Denver and Broomfield , sorted them into 1,000-head insect "lots," and transported them across the Continental Divide.

Cool, wet conditions affected the beetle count the following year, then there was the "surprise gift" in 2022, when the coalition received a misdelivered pack of 4,000 beetles, meant for the White River Alliance . A new relationship with the Bureau of Land Management in 2023 sent the group to collect beetles in the fields of southeastern Idaho , where "tons of these leafy spurge biocontrol beetles are just hanging out," said Emily Burke , conservation program manager for Friends of the Yampa . They collected and released more than 50,000 insects that year — a huge beetle boon for the mostly volunteer organization.

Then they got the grant.

In nearby Moffat County , Dinosaur National Monument was awarded more than half a million dollars in Inflation Reduction Act funds to spend on invasive plant mitigation, a program they called the Inundative Biological Control Strategy Project , or, releasing a bunch of beetles on a bunch of invasive plants.

Dinosaur contracted Friends of the Yampa to partner with and administer most of the funds, since they were already executing the ongoing project.

After a portion of funds were set aside for equipment and a seasonal position at the monument, Friends of the Yampa was put in charge of around $400,000 , to be disbursed by the federal government over six years, from 2024-30.

"The project had been going for nine years at that point, but it was very much on a shoestring budget, run mostly through volunteer hours," Burke said. "With this influx we were really able to ramp up our efforts. What we are trying to do is inundate the leafy spurge."

In 2024, with the new funding, Friends of the Yampa collected and released 110,420 beetles, just shy of the 126,740 beetles that it previously took them five years to accumulate.

Then, even more suddenly than they received the money, the grant was frozen.

As part of the Trump administration's February funding freeze, the organization was cut off from the remaining $337,196 of its award, meant to take the project through 2030.

"So now, we're really scrambling," Burke said. "We're not able to bring as many people to Idaho , we won't be able to release as many beetles, it'll have less of an effect on the leafy spurges."

Biocontrol 'til the cows come home

The thing is, leafy spurges thrive in riparian habitats, where the river carries around the shockingly resilient plant, which can plunge its roots 30 feet underground and produce up to 130,000 seeds per plant.

Another thing you'll find along the river banks of Routt and Moffat counties? Agriculture.

Agriculture and leafy spurges don't get along.

If the spurges find their way into a hayfield, that hay cannot be certified as coming from a "weed-free forage" farm, and won't be accepted by a number of state, federal and tribal agencies, including the U.S. Forest Service , Bureau of Land Management , National Parks and Monuments, Military Reservations, Tribal Lands, and National Fish & Wildlife Refuges.

Colorado State University found that leafy spurges can also reduce the capacity of rangeland and pastures that host cattle by 50% to 75%. The milky sap of spurges is toxic to cattle, and they will avoid grazing in areas where the plant is widespread.

Moffat County produced close to 30,000 acres of harvested hay in 2022, according to the U.S. Census of Agriculture, making it the county's largest crop. Hay also topped the rankings in Routt County , which has nearly 80,000 acres of hay-producing fields.

As for the cows, cattle made up Routt County's largest source of agricultural income in 2022, more than 70% of its total sales.

"There's a very clear economic impact," Burke said. "And not to get too partisan, but the project has great bipartisan support. It's one of the cool examples of how the environmental users of a river and the ag users of a river can collaborate on something."

What was once a 15-mile stretch of concentrated leafy spurge has spread over 100 miles to Steamboat Springs , into Dinosaur National Monument , and along irrigation ditches and tributaries.

On April 9 , chairs of the Routt County and Moffat County boards of county commissioners sent a joint letter to the U.S. Sens. Michael Bennet and John Hickenlooper and U.S. Reps. Joe Neguse and Jeff Hurd , urging them to reinstate the project's funding.

The commissioners worried that without the federal funding, they would not be able to meet a state requirement to contain "List B Noxious Weed Species," or species of plants that require a plan to prevent their spread.

Herbicides can kill off the spurge's foliage, but don't reduce its "overall viability," according to the Leafy Spurge Project . In other words, it will grow right back. The plant's extensive root system provides long-lasting stores of nutrients. Which is good news for the beetles, which spend most of their lives underground, feeding on the plant's roots.

For the humans who capture the beetles, though, that means the window to act is slim. After spending a growing year underground, adult beetles emerge once per year, in the spring and early summer, to feed on the plant and reproduce.

The U.S. Department of Agriculture recommends "careful planning" and "maintaining repetitive treatment over multiple consecutive years" to contain leafy spurges, while CSU Extension maintains that "a combination of methods is essential to return leafy spurge-infested ground to a productive state."

So, eat them, spray them, cut them down.

"Persistence is imperative to gain control," the CSU report adds.

What's next

With the funds locked up in the federal reimbursement system known as ASAP, Burke said she's spending a lot of her working hours just trying to figure out how to pivot their program.

She has appealed to the county commissioners and met with U.S. Rep. Joe Neguse , a Democrat, to discuss the impact of the funding freeze.

In the meantime, they'll host a pared-down version of their annual "Show Me Float," a river float with journalists and lawmakers to rally support for the project.

They've had to forgo one collection trip, canceled their youth program with Yampatika, an environmental education center in Steamboat Springs , and scaled back their Idaho collection trip. Releases from the river in Dinosaur National Monument were cancelled due to federal limits on park employees, then reinstated when those restrictions were lifted.

"We just have very limited funds right now," Burke said. "And our priority is getting as many bugs as possible with those very limited funds."