Taking On A Noxious Weed With Beetles

By: Farm Progress, Western Farmer-Stockman

Noxious weeds are simply trouble, sometimes breaking the lifecycle of native grassland areas by crowding out important plants vital to a local ecosystem. Dalmation toadflax is an escaped ornamental weed that has found its way into Colorado pastures, meadows, roadsides and rangland.

This is an aggressive plant, producing up to 500,000 seeds per year and while most of the seeds fall within 18-inches of the plant, they can stay viable for 10 years. In Larimer County, an innovative partnership has turned a stem weevil – specifically Mecinus janthiniformis – into an effect biocontrol for that troublesome toadflax.

Beetles were scattered through an area in Poudre Canyon that was burned by the High Park Fire in 2012. While the toadflax was present before the fire, noxious weeds can quickly expand after a fire possibly due to seed germination, growing seasons and lack of native vegetation as competition. The spread of Dalmation toadflax in the county resulted in a yellow hue to native grassland and forested landscape.

In 2013, the Colorado Department of Agriculture facilitated creation of the Poudre Invasive Species Partnership, made up of federal and state agencies, local entities and private landowners. This effort was performed and coordinated by the Larimer County Weed District, and included crews from CDA’s Palisade Insectary, Larimer County, U.S. Forest Service and Colorado Parks and Wildlife.