Noxious weeds are invasive plants that require immediate attention because of their far-reaching impacts, including impacts to the environment and economy.
Financial Impacts
- Increased crop production and processing costs
- Increased equipment wear, tear and fuel costs
- Reduce product/crop quality
- Increase the amount of water and nutrients required for crop production
- Reduce forage production for livestock and crop production
- Increase animal production costs and product quality
- Increase costs for transportation due to control and asphalt damage
- Increase costs at industrial and utility sites (costs to control weeds)
- Decrease land values
Ecological Impacts
- Decrease wildlife habitat
- Increase soil erosion by wind and water
- Decrease water quality and damage watersheds and systems
- Displace native, threatened and endangered species (both plant, animal, insects)
- Increased fire danger
Why are some weeds designated or declared noxious?
Noxious weeds are designated as being noxious or declared noxious by ruling or local advisory boards and meet one or more of the following criteria:
- Aggressively invades or is detrimental to economic crops or native plant communities
- Is poisonous to livestock
- Is a carrier of detrimental insects, diseases or parasites;
- The direct or indirect effect of the presence of this plant is detrimental to the environmentally sound management of natural or agricultural ecosystems.
How are noxious weeds prioritized?
The Colorado Department of Agriculture (CDA) prioritizes species by List A, B or C – as well as providing a Watch List of species that have the potential to threaten productivity and environmental concerns.The Watch List is intended for advisory and educational purposes only. It is provide to promote the identification and reporting to the Commissioner information/data that assists with determining which species should be designated noxious weeds.
- List A: Rare noxious weeds that must be eradicated statewide
- List B: discretely distributed noxious weeds that must be eradicated, contained or suppressed, depending on their location, to stop their continued spread.
- List C: Widespread and well-established noxious weeds in Colorado; control is recommended by the state and may be required by local government.
- Watch List: The Watch List is intended for advisory and educational purposes only. It is used to promote the identification and reporting to the Commissioner information and data that assists with determinations of which species should be designated noxious weeds.
- County Weed Programs: Find local County Weed Managers and Coordinators at the CDA web page, for more information for your locale.
Quick Facts on Noxious Weed Impacts
The following courtesy of the Colorado Department of Agriculture and El Paso County Community Services Department – Environmental Division.
- Noxious weeds are spreading rapidly. Many scientists believe that if the spread continues at its current rate, noxious weeds will dominate much of our range-lands and forests within a few decades, if corrective measures are not taken.
- Only about 10% of the earth’s 33 billion acres are arable. If you start reducing that 10% by millions of acres infested with non-productive weeds along with other crop destroying pests, you begin to decrease the land available for food production.
- Over the last 30 years the estimates for total losses due to weeds range from $6 to $18 billion per year. Currently in the United States there are 100 million acres infested with noxious weeds and this is growing by at least 8% each year.
- Noxious weeds have a substantial impact on the economy and may cause job losses. Unfortunately, the economic impact of noxious weeds is poorly understood. It has been estimated that the economic impact of leafy spurge in Montana, North Dakota, South Dakota, and Wyoming totals $129.5 million each year and may result in the loss of 1,433 jobs. In Montana alone, spotted knapweed is estimated to cost $42 million each year. This spent revenue could be better spent on job creation/support.
- Bison use was reduced 78% and deer use was reduced 83% on land invaded by leafy spurge (Trammell and butler, 1995)
- 7 rare and uncommon plant species were eliminated in 3 years due to spotted knapweed in Glacier National Park (Sheley et al., 2005)
- A 56% increase in water run-off and a 192% increase in soil erosion were noted on land invated and dominated by spotted knapweed (Lace et al., 1989)
- Purple loosestrife costs $45 million per year in control costs and forage losses in the United States (Pimentel et al., 2005)
- The direct and indirect economic impacts of spotted, diffuse and Russian knapweed cause an estimated $42 million in annual losses to the state of Montana (Hirsch and Leitch, 1996)
Noxious Weed Articles:
- Controlling Noxious Weeds
- Common Noxious Weeds In Our District
- Knapweeds, a Family of Noxious Weeds
- Identifying Hybrid Toadflax
- Free Virtual Noxious Weed Control Workshop
Noxious Weed Online Resources:
Downloadable Publications:
- Noxious Weed Control Book – El Paso County
- Noxious Weeds FAQ – El Paso County
- Quick Guide – Watch List – CDA
Additional Articles on Weed Removal:
- Time-saving green tech kills those “blasted weeds” without chemicals – Ben Cosworth, Gizmag, 01/21/2106
