“Invasive species are plants, animals, or pathogens that are non-native to the ecosystem under consideration and whose introduction causes or is likely to cause harm.” National Invasive Species Council.
Why do we care about weeds?
Invasive and noxious weeds can damage highways, cause wildfires, and threaten wildlife and human health. Noxious weeds in range and forest areas are problematic because of their nature to dominate plant communities and the detrimental impact they can have to wildlife and livestock populations. For more information, see Invasive Species Defined in a Policy Context: Recommendations from the Federal Invasive Species Advisory Committee.
- Use weed-seed free hay, feed grain, straw and mulch.
- Do not drive vehicles through weed infestations.
- Manage desirable vegetation to be competitive with weeds.
- Detect and eradicate new introductions with herbicides.
- Address large-scale infestations and stop the advancing front.
- Seed with desirable plants if necessary.
Insects as Biocontrol Agents
Insects and other arthropods are being used to control certain rangeland and wildland weeds.
The rust mite (Aceria anthocoptes), here on Canada thistle, may have potential as a biological control agent of this weed. Photo by Eric Erbe; digital colorization by Chris Pooley.
Colorado Department of Agriculture Insectary — offers the citizens of Colorado a biological control alternative to the use of chemicals for control of specific pests.
The high costs of noxious weed invasion, both environmental and economic, have been well documented. The new handbook, Developing a Handbook for Utilizing Livestock as a Tool in Noxious Weed Control in Nine Western States summarizes information about livestock grazing to control important noxious weeds in nine western states. Order Handbook.
These videos demonstrate how biocontrol is part of an IPM program: Biological Control of Leafy Spurge and Using Integrated Weed Management to Control Leafy Spurge
Cheatgrass (at right) is notorious for its ability to thrive in disturbed areas—common disturbances include construction, fire, floods, poor grazing activities, and intense recreation.
Herbicides are used in combination with other weed control methods to effectively decrease target weed populations and favor the growth of desirable plant specides. Herbicides should be used judiciously and according to label directions.
Forests and rangelands are home to many species of wildlife, and rely on this habitat for food, water and shelter. Many “weeds” in the agricultural context are important food sources for a variety of birds and other animals. Effective management of invasive species in forest and rangeland is of paramount importance to protect wildlife habitat and an IPM approach is the best way to achieve this goal.
Colorado Noxious Weeds — the Colorado Noxious Weed Act (Colorado Revised Statues Title 35. Article 5.5) designates classifications of noxious weeds.
Biology and Management of Downy Brome and Japanese Brome, George Beck, Colorado State University
Download the Cheatgrass Management Handbook, Rocky Mountain Cheatgrass Management Project.
Learn more about invasive weeds in wildfire areas — “Weeds of Larimer County Wildfire Areas”
What’s Invasive! — mobile app, bugwood.org