YAMPA RIVER LEAFY SPURGE PROJECT
Annual Biological Control Releases
What follows is a narrative overview of the biological control releases made by the YRLSP and its partners in the Yampa Basin.
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2019
In the first year of the YRLSP biological control release program, approximately 7,300 flea beetles (Aphthona spp.) collected by the CDA on the Front Range (and donated to the YRLSP) were released on or in the vicinity of the Yampa River State Wildlife Area (YRSWA).
2020
In June 2020, four YRLSP volunteers upped the ante by traveling to the Front Range to aid the CDA in their annual collection of leafy spurge biological control beetles. Under the tutelage of the CDA's John Kaltenbach, on the first day approximately 27,000 flea beetles were collected from the former Lowry Bombing and Gunnery Range east of Denver. Day two was then spent at the CDA facility in Broomfield, sorting the flea beetles from stray plant parts and the rest of the insect "bi-catch," before packaging them into 1000-insect lots for distribution by the CDA across Colorado. In return for our contributions, the YRLSP's share of the take was thirteen 1000-insect lots of Aphthona, and one lot of Oberea (Oberea is typically released in lots of only 100 insects).
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Upon our return to the Yampa Yalley, two additional days were spent releasing the biological control insects at thirteen separate locations in Routt and Moffat counties. In June, Routt County Weed Program also released 500 Aphthona northwest of Hayden. Then, in July 2020, YRLSP volunteers helped release an additional 10,000 flea beetles on the Yampa River State Wildlife Area, purchased by Tyler Jacox of Colorado Parks and Wildlife (CPW) from a vendor in Montana.
This brought the total for just the 2020 biological control releases alone in the Yampa Valley to approximately 23,600 insects—roughly a third as many again as recorded during the entire "legacy release" period of 1989–2017!
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2021
The YRLSP was looking forward to another successful volunteer collection trip to the former Lowry Bombing and Gunnery Range in 2021, but (despite the extreme drought conditions prevailing on the Western Slope) continuously cool, wet spring conditions on the Front Range resulted in poor collection numbers during test runs by CDA crews. Ultimately it became clear that a collection trip to the Front Range by YRLSP volunteers would have produced only limited returns.
Nevertheless, John Kaltenbach of the CDA was able to supply us with 3,000 Aphthona and 250 Oberea, while Tyler Jacox of CPW was able to acquire an additional 6000 Aphthona and 200 Oberea from the Montana vendor. All of these insects were released at new locations in the Yampa River State Wildlife Area and Moffat County. The Routt County Weed Program also released another 1000 Aphthona northwest of Hayden.
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2022
The YRLSP again traveled to the former Lowry Bombing and Gunnery Range in June of 2022, for another successful volunteer collection trip under the auspices of the Colorado Department of Agriculture. This time we brought home approximately 12,000 Aphthona and 200 Oberea, which were quickly released at sites in Moffat County. Another 2000 Aphthona from the Lowry collection were later released by John Kaltenbach in the Yampa River State Wildlife Area, during our two-day Youth Outreach event.
Tyler Jacox was again able to procure an additional 6000 Aphthona and 300 Oberea from the Montana vendor, all of which were also released in the Yampa River State Wildlife Area. A last-minute, surprise gift of an additional 4000 Aphthona were also added to the new releases on the YRSWA. (Originally intended for release in the White River basin, these were donated to the YRLSP by Deirdre Macnab of the White River Alliance, after they were mistakenly delivered to an address in Steamboat. With the clock ticking, and no one with the White River Alliance readily available to pick them up, Deirdre turned to the YRLSP for help rescuing the beetles.)
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The YRLSP also purchased an additional 6000 Aphthona and 200 Oberea from our Montana source, which were released at five sites in Moffat County. Finally, the Routt County Weed Program released an additional 1000 Aphthona from the CDA on private lands south of the YRSWA.
Overall, in 2022 a total of 18,400 biological control insects were released in Moffat County, and another 13,300 in Routt County, for a combined total of approximately 31,700 biocontrol beetles for the season.
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2023
The YRLSP expanded its biocontrol horizons in 2023 by traveling to Ashton, Idaho, to meet with Kim Ragotzkie, a contractor with the BLM. Kim and a YRLSP crew of three collected about 17,000 Aphthona and 1,000 Oberea in three to four hours on their first morning, and then spent another day and a half sorting the beetles from the by-catch (non-target insects and vegetation debris). After returning to Colorado, the majority of these beetles were immediately released on the YRSWA. Shane Talvacchio of the CPW had also purchased 6000 Aphthona and 300 Oberea from Montana, and coincidentally these were delivered to Shane just in time for joining the YRLSP crew, so by the end of the afternoon a collective 23,400 beetles had been released on four sites in the YRSWA. The remainder of the Idaho catch, another 1,000 Aphthona and 100 Oberea, were released at Deerlodge Park in Dinosaur National Monument.
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The CDA also supplied more beetles to the Yampa Basin in 2023 than in any previous year to date. Dinosaur National Monument received 12,000 Aphthona and 100 Oberea from the CDA in early July, for release in the monument’s Yampa Canyon. In late June, the Routt County Weed Program released 3,000 Aphthona from the CDA. The next day, the participants of the YRLSP's Show Me Float released another 5000 Aphthona and 170 Oberea on private lands just upstream from the Yampa Valley Golf Course. John Kaltenbach of the CDA then supplied an additional 9,000 Aphthona and 100 Oberea, which he released on the YRSWA during the YRLSP's Youth Outreach events in mid-July. The total for the beetles received from CDA for release in the Yampa Basin came to 29,000 Aphthona and 370 Oberea in 2023.
Thus, the total leafy spurge biological control insect releases made by the YRLSP and its partners came to a whopping 53,670 in 2023 (see table below).
In 2019, we tentatively set a goal to release at least 100,000 biocontrol insects in the Yampa basin over the first five years of the biocontrol program. In the first few years this seemed a high bar to reach, but most years the numbers we were able to release increased over the previous year—sometimes quite substantially. In the end, we were able to easily exceeded our cumulative goal in our fifth year of releases, as shown in the table below. You can click on the table to download a PDF copy.
Overview of the first five years of YRLSP biological control releases.
These totals include releases made by our county and federal partners.
2024
The YRLSP's biocontrol release program had its most successful year yet in 2024. First, Inundative Biological Control Strategy Project (IBCS) funds purchased 32,000 Aphthona and 50 Oberea from the CDA, collected from the Front Range. Fifteen thousand of the Aphthona were then released at the confluence of the Green and Yampa rivers in Dinosaur National Monument. The remainder of the CDA biocontrol insects were released at locations on the Yampa River State Wildlife Area, on State Trust Lands just south of the YRSWA, and on private lands in Moffat County. Shane Talvacchio of the CPW also purchased 2,400 Aphthona and 420 Oberea from the Montana vendor, for release in the YRSWA.
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Our second annual Idaho collection trip, also funded by the ​IBCS, brought a crew of thirteen individuals representing the YRLSP, Dinosaur National Monument, Colorado Department of Agriculture, Friends of the Yampa, and private landowners, to Ashton, Idaho, where we were joined again by Kim Ragotzkie, contractor with the BLM. Over two days the group netted, sorted and packaged up 87,500 Aphthona and 2,450 Oberea. John Kaltenbach took 10,100 of these back to the Front Range for release, and the remainder traveled back to Northwest Colorado and Dinosaur National Monument.
During a quick two-day raft trip, 36,000 Aphthona and 1,250 Oberea from the Idaho collection were soon released in the Little Yampa Canyon. An additional 24,500 Aphthona and 800 Oberea released on Bureau of Land Management lands just east of Cross Mountain Canyon, while another 10,000 Aphthona were released on private lands in Sunbeam, Colorado. Dinosaur National Monument released the final 7,000 Aphthona and 300 Oberea in Island Park, on the Green River in the Utah portion of the monument.
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All told, in 2024 the YRLSP and its partners released approximately 114,720 biological control insects in the Yampa River Basin and Dinosaur National Monument—rivalling the cumulative total for the previous five-year period!