Carfentrazone is an aryl- triazoline

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 ...

, used for pre-crop-establishment control of broadleaf

weed A weed is a plant considered undesirable in a particular situation, growing where it conflicts with human preferences, needs, or goals.Harlan, J. R., & deWet, J. M. (1965). Some thoughts about weeds. ''Economic botany'', ''19''(1), 16-24. Pla ...

s, including marshmallow, annual nettles, and volunteer cotton, and frequently in tank mixtures with knock-down herbicides, such as

glyphosate Glyphosate (IUPAC name: ''N''-(phosphonomethyl)glycine) is a broad-spectrum systemic herbicide and crop desiccant. It is an organophosphorus compound, specifically a phosphonate, which acts by EPSP inhibitor, inhibiting the plant enzyme 5-en ...

. Under the system of

HRAC classification The Herbicide Resistance Action Committee (HRAC) classifies herbicides by their mode of action (MoA) to provide a uniform way for farmers and growers to identify the agents they use and better manage pesticide resistance around the world. It is r ...

it is a Group 14 (numeric), E (global) or G (Australian), since it acts by membrane disruption, through the inhibition of

protoporphyrinogen oxidase Protoporphyrinogen oxidase or protox is an enzyme that in humans is encoded by the ''PPOX'' gene. Protoporphyrinogen oxidase is responsible for the seventh step in biosynthesis of protoporphyrin IX. This porphyrin is the precursor to hemoglobin, ...

. Carfentrazone is used on crops, fallows, forest plantations, industrial, horticultural and commercial areas. Carfentrazone is used in

Australia Australia, officially the Commonwealth of Australia, is a country comprising mainland Australia, the mainland of the Australia (continent), Australian continent, the island of Tasmania and list of islands of Australia, numerous smaller isl ...

, the

United Kingdom The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Northwestern Europe, off the coast of European mainland, the continental mainland. It comprises England, Scotlan ...

, the

European Union The European Union (EU) is a supranational union, supranational political union, political and economic union of Member state of the European Union, member states that are Geography of the European Union, located primarily in Europe. The u ...

, the

United States The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...

and India. It was introduced in 1997.

Mechanism and effects

Affected weeds rapidly absorb carfentrazone through foliage, and show symptoms within hours, of

desiccation Desiccation is the state of extreme dryness, or the process of extreme drying. A desiccant is a hygroscopic (attracts and holds water) substance that induces or sustains such a state in its local vicinity in a moderately sealed container. The ...

necrosis Necrosis () is a form of cell injury which results in the premature death of cells in living tissue by autolysis. The term "necrosis" came about in the mid-19th century and is commonly attributed to German pathologist Rudolf Virchow, who i ...

and death. It is often applied at 75 mL/ha in

, or less if part of a knockdown mixture with glyphosate, due to carfentrazone's prevention of weeds' metabolism, which reduces the translocation and effectiveness of glyphosate. Effectiveness is best when applied with much water, and reduced by high temperatures, sunlight and muddy or saline mix-water.

Safety

Carfentrazone is toxic to aquatic life, both in acute and chronic toxicities. In mammals, carfentrazone has a low toxicity, with an LD₅₀ of over 5000 mg/kg, tested orally in rats. For birds, carfentrazone is also of low toxicity.

References

Links

* {{Herbicides Herbicides Chloroarenes Fluoroarenes 1,2,4-Triazol-3-ones Carboxylic acids Group 14 herbicides