Little Beetles are Making a Big Difference in Northern Colorado
Site 8 BEFORE
Site 8 AFTER
BROOMFIELD, Colo. – Some little beetles are making a big difference controlling noxious weeds in Larimer County. The beetles, stem weevils called Mecinus janthiniformis, have eaten their way through hundreds of acres of Dalmatian toadflax, a state-listed noxious weed.
Dalmatian toadflax is an escaped ornamental weed typically found in pastures, meadows roadsides, and rangeland. Plants produce 500,000 seeds per year, most of these seeds fall within 18 inches of the plant, and stay viable for 10 years. The stem weevil has proven to be a successful biocontrol agent against this noxious weed.
The beetles were scattered through an area in Poudre Canyon that was burned by the High Park Fire in 2012. While the Dalmatian 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. The spread of the Dalmatian toadflax in Larimer County resulted in a yellow hue to native grassland and forested landscape.
In 2013, the Colorado Department of Agriculture facilitated the creation of the Poudre Invasive Species Partnership, which was made up of federal and state agencies, local entities and private landowners. The on-the-ground work was performed and coordinated by the Larimer County Weed District, and involved crews from CDA’s Palisade Insectary, Larimer County, U.S. Forest Service and Colorado Parks and Wildlife.
“Noxious weeds pose a threat to agriculture, Colorado’s natural heritage, and our quality of life. The partnership was effective due to the commitment by the entities involved to battle these destructive weeds including the on-the-ground leadership and coordination by the Larimer County Weed District,” said Steve Ryder, CDA’s State Weed Coordinator.
The partnership’s first goal was to establish the Mecinus weevils in the toadflax population and eventually grow enough of the beetles so they could be collected and sent to other toadflax populations in the state. The original weevils came from the Palisade Insectary, with an additional supply from Washington and Montana provided by the Animal and Plant Health Inspection Service (USDA APHIS).
CDA’s Insectary program, located in Palisade, is among only a handful of programs across the U.S. that provides farmers, ranchers and resource managers with dozens of species of beneficial insects and mites as tools for use in Integrated Pest Management programs. It produces and releases about 30 different species of biological control agents to combat noxious weeds and insect pests spreading throughout Colorado.
“It’s estimated that many of the monitoring sites have seen upwards of 95 percent control of the toadflax. This is a major biocontrol success story,” said Dan Bean, Director of the Palisade Insectary.
Other partners included the City of Greeley, City of Fort Collins, State Land Board, CDOT, USDA-Forest Service, USDA-APHIS, and two private landowners.