A noxious weed is a plant species that has been designated by country, state, provincial, or national agricultural authority 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.
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.
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.
Some guidelines to prevent the spread of noxious weeds are:
- Avoid driving through noxious weed-infested areas.
- Avoid transporting or planting seeds and plants that one can't identify.
- 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 for the specific plant. Burning poison ivy can be fatal to humans.
- Using only certified weed-free seeds for crops or gardens.
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.
Noxious weeds by country
||The examples and perspective in this article deal primarily with the English-speaking world and do not represent a worldwide view of the subject. (February 2013)|
New Zealand has had a series of Acts of Parliament relating to noxious weeds: Noxious Weeds Act, 1908, Noxious Weeds Act 1950, and the Noxious Plants Act 1978. The 1978 Act was repealed by the Biosecurity Act 1993 and words such as pest, organism and species are used in the new Act, rather than "noxious". Consequently, the term noxious weed is no longer used for official publications in New Zealand.
- Coupe, Sheena, ed. (1989). Frontier country: Australia's outback heritage. Vol. 1. Willougby: Weldon Russell. p. 298.
- http://www.cal-ipc.org/ip/definitions/index.php California-IPC. "Definitions." access date: 5/5/2010
- Prather pp. 27,45,53,67-73
- "Poison Ivy Identification and Control". Retrieved Apr 2012.
- "Idaho State Department of Agriculture". 2005. Retrieved Nov 2008.
- "National weeds lists". Department of Sustainability, Environment, Water, Population and Communities. 14 August 2012. Retrieved 25 August 2012.
- "Invasive and Noxious Weeds". USDA Natural Resources Conservation Service. Retrieved 25 August 2012.
- Noxious Weeds List at Weeds Australia
- New Zealand
- McLintock, A. H., ed. (1966). "Noxious Weeds Act of 1950". An Encyclopaedia of New Zealand.
- United States