Garlon
   HOME

TheInfoList



OR:

Triclopyr (3,5,6-trichloro-2-pyridinyloxyacetic acid) is an
organic compound Some chemical authorities define an organic compound as a chemical compound that contains a carbon–hydrogen or carbon–carbon bond; others consider an organic compound to be any chemical compound that contains carbon. For example, carbon-co ...
in the
pyridine Pyridine is a basic (chemistry), basic heterocyclic compound, heterocyclic organic compound with the chemical formula . It is structurally related to benzene, with one methine group replaced by a nitrogen atom . It is a highly flammable, weak ...
group that is used as a systemic foliar
herbicide Herbicides (, ), also commonly known as weed killers, are substances used to control undesired plants, also known as weeds.EPA. February 201Pesticides Industry. Sales and Usage 2006 and 2007: Market Estimates. Summary in press releasMain page f ...
and
fungicide Fungicides are pesticides used to kill parasitic fungi or their spores. Fungi can cause serious damage in agriculture, resulting in losses of yield and quality. Fungicides are used both in agriculture and to fight fungal infections in animals, ...
.


History

Triclopyr triethylammonium (TEA) was first registered in 1979 in the United States for use as an herbicide in non-crop areas and forestry to control broadleaf weeds and woody plants. A year later, in 1980, a formulation containing triclopyr butoxyethyl ester (BEE) was registered for similar applications. Both formulations expanded their usage to turf sites in 1984, and in 1985, triclopyr BEE was specifically registered for use on rangeland and permanent grass pastures. In 1995, the triclopyr TEA formulation received registration for use on rice crops to manage broadleaf weed species.


Uses

Triclopyr is a systemic herbicide and is selectively used to control dicotyledonous (broadleaf) weeds and woody plants while leaving monocotyledonous plants (such as grasses, bulbs, and
conifers Conifers () are a group of cone-bearing seed plants, a subset of gymnosperms. Scientifically, they make up the division Pinophyta (), also known as Coniferophyta () or Coniferae. The division contains a single extant class, Pinopsida. All e ...
) largely unaffected. It is classified as a WSSA (
Weed Science Society of America The Weed Science Society of America (WSSA) is a nonprofit, learned society focused on weed science. It was founded in 1956. The organization promotes research, education, and extension outreach, provides science-based information to the public a ...
) group 4 herbicide, indicating its mechanism of action involves mimicking the plant growth hormone
auxin Auxins (plural of auxin ) are a class of plant hormones (or plant-growth regulators) with some morphogen-like characteristics. Auxins play a cardinal role in coordination of many growth and behavioral processes in plant life cycles and are essent ...
. This disruption leads to abnormal and twisted plant growth, ultimately causing the treated plants to die and then decompose within one to two weeks following application. Effective application of triclopyr requires that plants are actively growing. In situations where there is flowing water at a treatment site, higher concentrations or repeated applications of the herbicide may be necessary to achieve the desired control. In addition to weed control, triclopyr has also been documented for use in controlling
rust fungus Rusts are fungal plant pathogens of the order Pucciniales (previously known as Uredinales) causing plant fungal diseases. An estimated 168 rust genera and approximately 7,000 species, more than half of which belong to the genus ''Puccinia'', are ...
on soybean crops. In the USA, it is sold under the trade names Garlon, Remedy, Turflon, Weed-B-Gon (purple label), Brush-B-Gon, and RoundUp, and in the United Kingdom as SBK Brushwood Killer. It is also a major ingredient in Confront. It is a widely used herbicide with active registrations in the USA, Brazil, Australia, Canada, Morocco, Paraguay, South Africa and Southeast Asia.


Environmental effects

Triclopyr, including its ester and amine salt forms, is rapidly converted to the triclopyr acid form in the environment. The acid form is largely water-soluble, while the ester form exhibits lower solubility. Triclopyr has a low
vapor pressure Vapor pressure or equilibrium vapor pressure is the pressure exerted by a vapor in thermodynamic equilibrium with its condensed phases (solid or liquid) at a given temperature in a closed system. The equilibrium vapor pressure is an indicat ...
, indicating a limited tendency to volatilize into the atmosphere. In aquatic environments, triclopyr degradation is accelerated by light, with a reported half-life of approximately 1 day under light conditions. Without light, it is more persistent in water, with a half-life of around 142 days. Triclopyr undergoes relatively rapid breakdown in soil, primarily through microbial activity. Soil half-lives typically range from 8 to 46 days, with longer persistence observed in deeper, less oxygenated soils. Although triclopyr is considered mobile in soil, studies have indicated limited movement below depths of 15 to 90 centimeters. Its movement in soil is influenced by factors such as organic matter content and rainfall. As a systemic herbicide, triclopyr is absorbed by plants through both leaves and roots and tends to accumulate in active growth regions. The rate of breakdown within plants varies widely depending on the species; reported half-lives in plants range from 3 to 24 days, with some plants like barley and wheat showing more rapid degradation. The compound is slightly toxic to ducks ( LD50 = 1698 mg/kg) and quail (LD50 = 3000 mg/kg). It has been found nontoxic to bees and marginally toxic to fish (rainbow trout LC50 (96 hr) = 117 ppm).''Environmental Fate Of Triclopyr''
Carissa Ganapathy, Environmental Monitoring & Pest Management Branch Department of Pesticide Regulation Sacramento, CA (dead link 23 October 2023)
Garlon's fact sheet for their triclopyr ester product indicates that triclopyr is highly toxic to fish, aquatic plants, and aquatic invertebrates, and should never be used in waterways, wetlands, or other sensitive habitats. This is only for the triclopyr ester product, not for the triclopyr amine product.


References


External links


archived Triclopyr Technical Fact Sheet – National Pesticide Information Center

Triclopyr General Fact Sheet – National Pesticide Information Center


* {{Herbicides Auxinic herbicides Chloropyridines Carboxylic acids Ethers Fungicides Pyridines Group 4 herbicides