Related Research Articles
Herbicides, also commonly known as weedkillers, are substances used to control undesired plants, also known as weeds. Selective herbicides control specific weed species, while leaving the desired crop relatively unharmed, while non-selective herbicides can be used to clear waste ground, industrial and construction sites, railways and railway embankments as they kill all plant material with which they come into contact. Apart from selective/non-selective, other important distinctions include persistence, means of uptake, and mechanism of action. Historically, products such as common salt and other metal salts were used as herbicides, however these have gradually fallen out of favor and in some countries a number of these are banned due to their persistence in soil, and toxicity and groundwater contamination concerns. Herbicides have also been used in warfare and conflict.
Pesticide resistance describes the decreased susceptibility of a pest population to a pesticide that was previously effective at controlling the pest. Pest species evolve pesticide resistance via natural selection: the most resistant specimens survive and pass on their acquired heritable changes traits to their offspring. If a pest has resistance then the pesticide lacks efficacy – efficacy and resistance are inversely related.
Weed control is the botanical component of pest control, which attempts to stop weeds, especially noxious weeds, from competing with desired flora and fauna including domesticated plants and livestock, and in natural settings preventing non native species competing with native species.
Glyphosate is a broad-spectrum systemic herbicide and crop desiccant. It is an organophosphorus compound, specifically a phosphonate, which acts by inhibiting the plant enzyme 5-enolpyruvylshikimate-3-phosphate synthase. It is used to kill weeds, especially annual broadleaf weeds and grasses that compete with crops. Its herbicidal effectiveness was discovered by Monsanto chemist John E. Franz in 1970. Monsanto brought it to market for agricultural use in 1974 under the trade name Roundup. Monsanto's last commercially relevant United States patent expired in 2000.
Paraquat (trivial name; ), or N,N′-dimethyl-4,4′-bipyridinium dichloride (systematic name), also known as methyl viologen, is an organic compound with the chemical formula [(C6H7N)2]Cl2. It is classified as a viologen, a family of redox-active heterocycles of similar structure. This salt is one of the most widely used herbicides. It is quick-acting and non-selective, killing green plant tissue on contact. It is also toxic (lethal) to human beings and animals due to its redox activity, which produces superoxide anions. It has been linked to the development of Parkinson's disease and is banned in several countries.
Hexazinone is an organic compound that is used as a broad spectrum herbicide. It is a colorless solid. It exhibits some solubility in water but is highly soluble in most organic solvents except alkanes. A member of the triazine class herbicides, it is manufactured by DuPont and sold under the trade name Velpar.
Avena sterilis is a species of grass weed, and its seeds are edible.
Glufosinate is a naturally occurring broad-spectrum herbicide produced by several species of Streptomyces soil bacteria. Glufosinate is a non-selective, contact herbicide, with some systemic action. Plants may also metabolize bialaphos, another naturally occurring herbicide, directly into glufosinate. The compound irreversibly inhibits glutamine synthetase, an enzyme necessary for the production of glutamine and for ammonia detoxification, giving it antibacterial, antifungal and herbicidal properties. Application of glufosinate to plants leads to reduced glutamine and elevated ammonia levels in tissues, halting photosynthesis and resulting in plant death.
Amaranthus tuberculatus, commonly known as roughfruit amaranth, rough-fruited water-hemp, tall waterhemp, or common waterhemp, is a species of flowering plant. It is a summer annual broadleaf with a germination period that lasts several months. Tall waterhemp has been reported as a weed in 40 of 50 U.S. states.
Lactofen is a complex ester of acifluorfen and is a nitrophenyl ether selective herbicide and fungicide. It is used in postemergence applications to certain crops which are resistant to its action. The name "Lactofen" is approved by the American National Standards Institute and the Weed Science Society of America, and is also approved in China (乳氟禾草灵).
Mesotrione is the ISO common name for an organic compound that is used as a selective herbicide, especially in maize. A synthetic inspired by the natural substance leptospermone, it inhibits the enzyme 4-hydroxyphenylpyruvate dioxygenase (HPPD) and is sold under brand names including Callisto and Tenacity. It was first marketed by Syngenta in 2001.
4-Hydroxyphenylpyruvate dioxygenase (HPPD) inhibitors are a class of herbicides that prevent growth in plants by blocking 4-Hydroxyphenylpyruvate dioxygenase, an enzyme in plants that breaks down the amino acid tyrosine into molecules that are then used by plants to create other molecules that plants need. This process of breakdown, or catabolism, and making new molecules from the results, or biosynthesis, is something all living things do. HPPD inhibitors were first brought to market in 1980, although their mechanism of action was not understood until the late 1990s. They were originally used primarily in Japan in rice production, but since the late 1990s have been used in Europe and North America for corn, soybeans, and cereals, and since the 2000s have become more important as weeds have become resistant to glyphosate and other herbicides. Genetically modified crops are under development that include resistance to HPPD inhibitors. There is a pharmaceutical drug on the market, nitisinone, that was originally under development as an herbicide as a member of this class, and is used to treat an orphan disease, type I tyrosinemia.
Quinclorac is a selective herbicide used primarily to control weeds in rice crops, but is also used on other agricultural crops and is found in some household herbicides for lawn use. Most lawn maintenance companies use the product for the control of annual grass weeds like crabgrass.
Weed science is a scientific discipline concerned with plants that may be considered weeds, their effects on human activities, and their management "a branch of applied ecology that attempts to modify the environment against natural evolutionary trends.".
Jonathan Gressel is an Israeli agricultural scientist and Professor Emeritus at the Weizmann Institute of Science in Rehovot, Israel. Gressel is a "strong proponent of using modern genetic techniques to improve agriculture" especially in third world and developing countries such as Africa. In 2010, Gressel received Israel's highest civilian award, the Israel Prize, for his work in agriculture
Fluazifop is the ISO common name for an organic compound that is used as a selective herbicide. The active ingredient is the 2R enantiomer at its chiral centre and this material is known as fluazifop-P when used in that form. More commonly, it is sold as its butyl ester, fluazifop-P butyl with the brand name Fusilade.
Indaziflam is a preemergent herbicide especially for grass control in tree and bush crops.
Sethoxydim is a postemergent herbicide for control of grass weeds in a wide variety of horticultural crops.
Tribenuron in the form of tribenuron-methyl is a sulfonylurea herbicide. As such it is in WSSA/new HRAC group 2, and legacy HRAC group B, and its mode of action is the inhibition of acetolactate synthase.
Chlorsulfuron is an ALS inhibitor herbicide, and is a sulfonylurea compound. It was discovered by George Levitt in February 1976 while working at DuPont, which was the patent assignee.
References
- ↑ Society Information
- ↑ Cambridge University Press
- ↑ Society Information
- ↑ Heap, Ian. "International Survey of Herbicide Resistant Weeds".
- ↑ Weed Science Society of America. "Summary of Herbicide Mechanism of Action According to the Weed Science Society of America (WSSA)" (PDF).
- ↑ "Weed Science Society of America partners with Cambridge University Press". Nursery Management. 20 September 2016. Retrieved 15 March 2017.
| General | |
|---|---|
| National libraries | |
 | This article about a botany organization is a stub. You can help Wikipedia by expanding it. |