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Noxious weed

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A mature cotton thistle, an invasive weed in Australia.

A noxious weed, harmful weed or injurious weed is a weed that has been designated by an agricultural or other governing authority as a plant that is harmful to agricultural or horticultural crops, natural habitats or ecosystems, or humans or livestock. Most noxious weeds have been introduced into an ecosystem by ignorance, mismanagement, or accident. Some noxious weeds are native, though many localities define them as necessarily being non-native. Typically they are plants that grow aggressively, multiply quickly without natural controls (native herbivores, soil chemistry, etc.), and display adverse effects through contact or ingestion. Noxious weeds are a large problem in many parts of the world, greatly affecting areas of agriculture, forest management, nature reserves, parks and other open space.[1]

Many noxious weeds have come to new regions and countries through contaminated shipments of feed and crop seeds or were intentionally introduced as ornamental plants for horticultural use.

Some "noxious weeds", such as ragwort, produce copious amounts of nectar, valuable for the survival of bees and other pollinators, or other advantages like larval host foods and habitats. In the US, wild parsnip Pastinaca sativa, for instance, provides large tubular stems that some bee species hibernate in, larval food for two different swallowtail butterflies, and other beneficial qualities.[2]

Types

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The algae Caulerpa Taxifolia, is a noxious marine weed nicknamed killer algae. This is a picture of it invading a native plant bed.
This is a parasitic noxious weed, Striga gesnerioides, commonly called Witchweed.
This is a terrestrial noxious weed, Drymaria arenarioides commonly called Lightning weed. It is sometimes confused with daisies.

Some noxious weeds 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.[3] There are marine, terrestrial, and parasitic noxious weeds.[4]

Control

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Main article: Weed 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 cannot 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 for the specific plant. Burning poison ivy can be fatal to humans.[5]
  4. Using only certified weed-free seeds for crops or gardens.[6]

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.[6]

Insects and fungi have long been used as biological controls of some noxious weeds and more recently nematodes have also been used.[7]

Eradication

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According to control experts, there are chemical, physical ways, and environmental ways of eradicating noxious weeds. Those include pulling the entire weed out of the ground,[8] spraying herbicide if it's a large area,[9] and using machines to turn over the soil.[8] According to farmers, using goats can prove a more ecological way of getting rid of noxious weeds, instead of using herbicide.[10][11] Also, overplanting a native species is a long term solution in eradicating noxious weeds.[8]

Controversy and biases

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Agricultural needs, desires, and concerns do not always mesh with those of other areas, such as pollinator nectar provision.[12] Ragwort, for instance, was rated as the top flower meadow nectar source in a UK study, and in the top ten in another. Its early blooming period is also particularly helpful for the establishment of bumblebee colonies.[13] Thistles that are considered noxious weeds in the US and elsewhere, such as Cirsium arvense and Cirsium vulgare, have also rated at or near the top of the charts in multiple UK studies for nectar production, one of its native locations. These thistles also serve as a larval host plant for the painted lady butterfly. There can be, therefore, a conflict between agricultural policy and point of view and the point of view of conservationists or other groups.[citation needed]

By country

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Australia

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See also: Invasive species in Australia

In Australia, the term "noxious weed" is used by state and territorial governments.[14][example needed]

This is a mat of Alligator weeds.

Some noxious weeds in Australia are Alligator weeds, Horsetails, and Branched broomrape.[15] The government of Victoria will get rid of all these plants for free. Alligator weeds are banned in all the states and territories of Australia.[15] They can create large mats that can cause considerable blockages of waterways.[15] Horsetails are poisonous to livestock. They are also extremely challenging to eradicate, as they can fragment off and the fragmented pieces can grow new plants.[15] Kind of like succulents. Branched broomrapes are parasitic noxious weeds.[15] They attract themselves to the roots of other plants and extract water and nutrients.[15]

Canada

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In Canada, constitutional responsibility for the regulation of agriculture and the environment is shared between the federal and provincial governments. The federal government through the Canadian Food Inspection Agency (CFIA) regulates invasive plants under the authority of the Plant Protection Act, the Seeds Act and statutory regulations. Certain plant species have been designated by the CFIA as noxious weeds in the Weed Seeds Order.[16]

Each province also produces its own list of prohibited weeds. In Alberta, for example, a new Weed Control Act was proclaimed in 2010 with two weed designations: "prohibited noxious" (46 species) which are banned across Alberta, and "noxious" (29 species) which can be restricted at the discretion of local authorities.[17]

New Zealand

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See also: Invasive species in New Zealand

New Zealand has had a series of Acts of Parliament relating to noxious weeds: the Noxious Weeds Act 1908,[18] the Noxious Weeds Act 1950,[19] and the Noxious Plants Act 1978.[20] The last was repealed by the Biosecurity Act 1993, which used words such as "pest", "organism" and "species", rather than "noxious". Consequently, the term "noxious weed" is no longer used in official publications in New Zealand.[21] According to this Act, control of the majority of problem weeds, now called 'pest plants', is the responsibility of Regional Councils, or unitary authorities, in a few councils.

This is Broad-Leaved Dock.

Some common noxious weeds in New Zealand are Broad-Leaved Dock, English Ivy, and Oxalis.[22] These plants may be aesthetically pleasing, but they smother native plants and are hard to eradicate.[22]

United Kingdom

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The Weeds Act 1959 (7 & 8 Eliz. 2. c. 54) covers Great Britain,[23] It is mainly relevant to farmers and other rural settings rather than the allotment or garden-scale growers. Five "injurious" weeds are listed. The word "injurious" means in this context harmful to agriculture,[24] not liable to cause injury. All the species listed apart from ragwort are edible and appear in Richard Mabey's book Food for Free. They are all native plants. These are:

The Department for Environment, Food and Rural Affairs (DEFRA) provides guidance for the removal of these weeds from infested land. Much of this is oriented towards the use of herbicides.

The act does not place any automatic legal responsibility on landowners to control the weeds, or make growing them illegal, but they may be ordered to control them. Most common farmland weeds are not "injurious" within the meaning of the Weeds Act and many such plant species have conservation and environmental value. The various UK government agencies responsible have a duty to try to achieve a reasonable balance among different interests. These include agriculture, countryside conservation and the general public.

Section 14 of the Wildlife and Countryside Act 1981 makes it an offence to plant or grow certain specified foreign invasive plants in the wild, listed in schedule 9 of the act, including giant hogweed and Japanese knotweed. Some local authorities have by-laws controlling these plants.[citation needed] There is no statutory requirement for landowners to remove these plants from their property.

Northern Ireland is covered by the Noxious Weeds (Northern Ireland) Order 1977 (NISI 1977/52).[25] This mirrors the Great Britain legislation, and covers the same five species, with the addition of:

United States

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See also: Invasive species in the United States
These are ox-eye daisies.

The federal government defines noxious weeds under the Federal Noxious Weed Act of 1974. Noxious weeds are also defined by the state governments in the United States.[26] Noxious weeds came to the U.S. by way of colonization.[27] Some wildflowers are lesser known noxious weeds. A few of them are banned in certain states.[28] For example, the Ox-eye daisy came to the Americas over in colonizers' seed bags and has become the common daisy seen at roadsides. It is prohibited in 10 states for agriculture,[28] and is the most banned out of any wildflower.

See also

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References

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  1. ^ "Cal-IPC: Invasive Plant Definitions, What Makes a Plant "Invasive"?". www.cal-ipc.org. California Invasive Plant Council. Retrieved 20 July 2017.
  2. ^ "Wild Parsnip". Illinois Wildflowers.info. Retrieved 13 November 2017.
  3. ^ Prather pp. 27,45,53,67-73
  4. ^ USDA (December 10, 2010). "Federal Noxious Weed List" (PDF). Retrieved April 25, 2024.
  5. ^ "Poison Ivy Identification and Control" (PDF). Archived (PDF) from the original on 2015-06-22. Retrieved 2015-06-22.
  6. ^ a b "Idaho State Department of Agriculture". 2005. Archived from the original on 19 July 2008. Retrieved 2 November 2008.
  7. ^ V S Rao (2 January 2000). Principles of Weed Science, Second Edition. Taylor & Francis. pp. 319–. ISBN 978-1-57808-069-4.
  8. ^ a b c Fisheries, Agriculture and (2011-06-24). "Physical control methods". www.business.qld.gov.au. Retrieved 2024-05-07.
  9. ^ Department of Jobs, Precincts and Regions (2020-06-19). "Prescribed measures for the control of noxious weeds - Agriculture". Agriculture Victoria. Retrieved 2024-05-07.
  10. ^ "No kidding! Goats are proving fine at controlling noxious weeds". ABC News. 2021-02-10. Retrieved 2024-05-07.
  11. ^ Lewis, Becca (2024-01-31). "You Can Actually Rent Goats to Eat Weeds in Your Yard". Lifehacker. Retrieved 2024-05-07.
  12. ^ "Which flowers are the best source of nectar?". Conservation Grade. 2014-10-15. Retrieved 2017-10-18.
  13. ^ Hicks, DM; Ouvrard, P; Baldock, KCR (2016). "Food for Pollinators: Quantifying the Nectar and Pollen Resources of Urban Flower Meadows". PLOS ONE. 11 (6): e0158117. Bibcode:2016PLoSO..1158117H. doi:10.1371/journal.pone.0158117. PMC 4920406. PMID 27341588.
  14. ^ "National weeds lists". Department of Sustainability, Environment, Water, Population and Communities. 14 August 2012. Retrieved 25 August 2012.
  15. ^ a b c d e f Department of Jobs, Precincts and Regions (2021-03-02). "State prohibited weeds - Agriculture". Agriculture Victoria. Retrieved 2024-05-08.
  16. ^ "Invasive Plants Policy". Canadian Food Inspection Agency. 2012-02-20. Retrieved 31 December 2013.
  17. ^ "Alberta Invasive Plant Identification Guide" (PDF). Wheatland County. 2013. Retrieved 25 July 2020.
  18. ^ http://www.enzs.auckland.ac.nz/docs/1908/1908C133.pdf [bare URL PDF]
  19. ^ McLintock, Alexander Hare; Arnold John Heine, Antarctic Division; Taonga, New Zealand Ministry for Culture and Heritage Te Manatu. "NOXIOUS WEEDS ACT OF 1950". An encyclopaedia of New Zealand, edited by A. H. McLintock, 1966. Retrieved 2022-02-24.
  20. ^ "Noxious Plants Act 1978 (1978 No 15)". www.nzlii.org. Retrieved 2022-02-24.
  21. ^ "Biosecurity Act 1993 No 95 (as at 28 October 2021), Public Act Schedule 3 enactments repealed – New Zealand Legislation". www.legislation.govt.nz. Retrieved 2022-02-24.
  22. ^ a b "Common Noxious Weeds in New Zealand". Crewcut Lawn & Garden. 2021-10-21. Retrieved 2024-05-07.
  23. ^ Weeds Act 1959
  24. ^ "Injurious weeds".
  25. ^ Noxious Weeds (Northern Ireland) Order 1977
  26. ^ "Invasive and Noxious Weeds". USDA Natural Resources Conservation Service. Retrieved 25 August 2012.
  27. ^ "Invasive Species as a Metaphor for Colonization". Rewilding Magazine. 2022-06-16. Retrieved 2024-05-03.
  28. ^ a b "Problem Plants: Noxious Weeds, Invasive Wildflowers, and Prohibited Plants". American Meadows. Retrieved 2024-05-03.
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Australia
New Zealand
United States
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