Noxious weed

In 1907 seven hundred cattle were killed overnight in Australia by a poisonous weed.^[1]

A noxious weed is an invasive species of a plant that has been designated by country, state or provincial, or national agricultural authorities as one that is injurious to agricultural and/or horticultural crops, natural habitats and/or ecosystems, and/or humans or livestock. Most noxious weeds are introduced species (non-native) and have been introduced into an ecosystem by ignorance, mismanagement, or accident. Occasionally some are native. Typically they are plants that grow aggressively, multiply quickly without natural controls (native herbivores, soil chemistry, etc.), and adversely affect native habitats, croplands, and/or are injurious to humans, native fauna, and livestock through contact or ingestion. Noxious weeds are a large problem in many parts of the world, greatly affecting areas of agriculture, forest management, nature preserves and parks, and other open space lands.^[2]

Criteria

These weeds are typically agricultural pests, though many also have impacts on natural areas. Many noxious weeds have come to new regions and countries through contaminated shipments of feed and crop seeds or intentional introductions such as ornamental plants for horticultural use. For a proportional example, the Idaho Department of Agriculture (U.S.) has around 300 introduced or exotic species listed with 36 classified as noxious weeds (invasive species).

The legal designation of noxious weed for a plant species can use these four criteria:

1. It is present in but not native to state-province-ecosystem.
2. It is potentially more harmful than beneficial to that area.
3. Its management, control, or eradication is economically and physically feasible.
4. The potential adverse impact of it exceeds the cost of its control.^[3]

Types

There are types of noxious weeds that are harmful or poisonous to humans, domesticated grazing animals, and wildlife. Open fields and grazing pastures with disturbed soils and open sunlight are often more susceptible. Protecting grazing animals from toxic weeds in their primary feeding areas is therefore important.^[4]

Control

Some guidelines to prevent the spread of noxious weeds are:

1. Avoid driving through noxious weed-infested areas.
2. Avoid transporting or planting seeds and plants that one can't identify.
3. For noxious weeds in flower or with seeds on plants, pulling 'gently' out and placing in a secure closable bag is recommended. Disposal such as hot composting or contained burning is done when safe and practical.
4. Using only certified weed-free seeds for crops or gardens.^[5]

Maintaining control of noxious weeds is important for the health of habitats, livestock, wildlife and native plants, and of humans of all ages. How to control noxious weeds depends on the surrounding environment and habitats, the weed species, the availability of equipment, labor, supplies, and financial resources. Laws often require that noxious weed control funding from governmental agencies must be used for eradication, invasion prevention, or native habitat and plant community restoration project scopes.^[5]

See also

• Weed
• International Plant Protection Convention

References

1. ^ Coupe, Sheena, ed (1989). Frontier country: Australia's outback heritage. Vol. 1. Willougby: Weldon Russell. p. 298. 
2. ^ http://www.cal-ipc.org/ip/definitions/index.php California-IPC. "Definitions." access date: 5/5/2010
3. ^ Prather, Timothy (2002). Idaho's Noxious Weeds. University of Idaho. 
4. ^ Prather pp. 27,45,53,67-73
5. ^ ^{a b} "Idaho State Department of Agriculture". 2005. http://www.agri.idaho.gov/Categories/PlantsInsects/NoxiousWeeds/FAQs.php. Retrieved Nov 2008. 

Further reading

• "Noxious weed free forage and straw certification program." 2006. State of Idaho. Nov. 2008 http://www.agri.idaho.gov
• Taylor, Ronald. Northwest Weeds. Montana: Mountain Press Publishing Company, 1990.
• U.S. Department of Agriculture Forest Services. Notes on Western Range Forbs. Washington: U.S. Government Printing Office, 1996.
• Sheley, Roger, James Jacobs, and John Martin. "Integrating 2,4-D and sheep grazing to rehabilitate spotted knapweed infestations." Journal of Range Management (2004): Academic Search Premier. EBSCO Albertson's Library, Boise, ID. 04 Nov. 2008 http://www.jstor.org/stable/4003861
• Roché, C T, et al. "Tracking an invader to its origins: the invasion case history of Crupina vulgaris." Weed Research 43.3 (June 2003): 177-189. Academic Search Premier. EBSCO. Albertson's Library, Boise, ID. 4 Nov. 2008 <http://search.ebscohost.com/login.aspx?direct=true&db=aph&AN=9732499&site=ehost-live>.

External links

• Bureau of Land Management: Weeds
• US-Department of Agriculture: Invasive and Noxious Weeds
• Montana's Weed Awareness Program: Pulling Together
• Noxious Weed Photos, King County, Washington State
• USDA Noxious Weed Program
• cal-ipc: "Noxious Weed definitions"
• Weeds Australia - Noxious Weeds List