Tri-allate or triallate is a selective pre-emergent

thiocarbamate In organic chemistry, thiocarbamates (thiourethanes) are a family of organosulfur compounds. As the prefix ''thio-'' suggests, they are sulfur analogues of carbamates. There are two isomeric forms of thiocarbamates: ''O''-thiocarbamates, (ester ...

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 to control wild oats and sundry grasses and

broadleaf weed Broadleaf weeds are dicotyledonous weeds that may grow in lawns, gardens or yards. They can be easy to spot when growing among grasses. They are tougher than grassy monocot weeds, multiply with ease, and can be very hard to eradicate. Basic charact ...

s, often co-applied with

trifluralin Trifluralin is a common pre-emergent selective herbicide, a dinitroaniline. With about used in the United States in 2001, and in 2012, it is one of the most widely used herbicides. Trifluralin is also used in Australia, New Zealand, Brazil an ...

, which is much weaker against wild oats than tri-allate. Residual control can be expected for 6 to 8 weeks. It is used in Australia, and the United States. It was first registered in 1961. In 2001, US agriculture used annually. Tri-allate is a

mitosis Mitosis () is a part of the cell cycle in eukaryote, eukaryotic cells in which replicated chromosomes are separated into two new Cell nucleus, nuclei. Cell division by mitosis is an equational division which gives rise to genetically identic ...

-inhibitor; its HRAC classification is Group J (Aus), Group K3 (global),

Group 15 , - ! colspan=2 style="text-align:left;" , ↓ Period , - ! 2 , , - ! 3 , , - ! 4 , , - ! 5 , , - ! 6 , , - ! 7 , , - , colspan="2", ---- ''Legend'' A pnictogen ( or ; from "to choke" and -gen, "generator") is any ...

(numeric). Affected weeds are prevented from germinating, or their shoots will be swollen and bright green.

Environmental behaviour

Under very dry conditions, tri-allate can persist in soil for several months, and can damage field

oat The oat (''Avena sativa''), sometimes called the common oat, is a species of cereal grain grown for its seed, which is known by the same name (usually in the plural). Oats appear to have been domesticated as a secondary crop, as their seeds ...

s and

sorghum ''Sorghum bicolor'', commonly called sorghum () and also known as great millet, broomcorn, guinea corn, durra, imphee, jowar, or milo, is a species in the Poaceae, grass genus ''Sorghum (genus), Sorghum'' cultivated for its grain. The grain i ...

. Degradation is dependent on soil microörganisms and moisture levels. Tri-allate is nontoxic to birds and bees, though it is very toxic to aquatic life. It doesn't

bioaccumulate Bioaccumulation is the gradual accumulation of substances, such as pesticides or other chemicals, in an organism. Bioaccumulation occurs when an organism absorbs a substance faster than it can be lost or eliminated by catabolism and excretion. Th ...

in plants, and has low mobility in soil. The aquatic toxicity is most potent against

invertebrates Invertebrates are animals that neither develop nor retain a vertebral column (commonly known as a ''spine'' or ''backbone''), which evolved from the notochord. It is a paraphyletic grouping including all animals excluding the chordate subphylum ...

and

algae Algae ( , ; : alga ) is an informal term for any organisms of a large and diverse group of photosynthesis, photosynthetic organisms that are not plants, and includes species from multiple distinct clades. Such organisms range from unicellular ...

. The EPA says "the overall ecological risk associated with the use of triallate is low". The average soil

half life Half-life is a mathematical and scientific description of exponential or gradual decay. Half-life, half life or halflife may also refer to: Film * ''Half-Life'' (film), a 2008 independent film by Jennifer Phang * '' Half Life: A Parable for t ...

is 82 days in "typical" conditions; it is also measured at 46 days, under "field" conditions. Similar half-life is seen in water sediment and in acidic (pH 9) solution.

Properties

Triallate is synthesised from diisopropylamine,

phosgene Phosgene is an organic chemical compound with the formula . It is a toxic, colorless gas; in low concentrations, its musty odor resembles that of freshly cut hay or grass. It can be thought of chemically as the double acyl chloride analog of ...

and 2,3,4-trichloro-phenyl-1-thiol. Its

surface tension Surface tension is the tendency of liquid surfaces at rest to shrink into the minimum surface area possible. Surface tension (physics), tension is what allows objects with a higher density than water such as razor blades and insects (e.g. Ge ...

is 0.049 N/m, as a 90% solution at 20 °C.

Monsanto The Monsanto Company () was an American agrochemical and agricultural biotechnology corporation founded in 1901 and headquartered in Creve Coeur, Missouri. Monsanto's best-known product is Roundup, a glyphosate-based herbicide, developed ...

manufactured it in the 1960s by the reaction of diisopropylthiocarbamate salt with 1,1,1,3-tetrachloro-propene. It is soluble in acetone, ether, ethyl alcohol, heptane, benzene, ethyl acetate and most organic solvents. Diallate is almost identical, but missing one of triallate's 3 chlorine atoms. Unlike triallate, it has cis- and trans-

isomer In chemistry, isomers are molecules or polyatomic ions with identical molecular formula – that is, the same number of atoms of each element (chemistry), element – but distinct arrangements of atoms in space. ''Isomerism'' refers to the exi ...

Health

Exposure to large amounts of tri-allate may harm the liver, spleen and kidneys. The EPA considers tri-allate to be a possible carcinogen, the result being "borderline" statistically significant in a trial on mice, though their rough estimate is that the chance of cancer from dietary triallate is one in 14 million. This trial only showed an increased incidence of tumors in one measured category, in a sample size of 15. Diallate, a very similar herbicide, was carcinogenic, possibly prompting the concern for triallate. In tests on

rabbit Rabbits are small mammals in the family Leporidae (which also includes the hares), which is in the order Lagomorpha (which also includes pikas). They are familiar throughout the world as a small herbivore, a prey animal, a domesticated ...

s, no fetotoxic or

teratogenic Teratology is the study of abnormalities of physiological development in organisms during their life span. It is a sub-discipline in medical genetics which focuses on the classification of congenital abnormalities in dysmorphology caused by ...

effects were observed, although a small decrease of birth weight was strongly evidenced.

Regulatory status

Tri-allate is limited to the US states of California, Colorado, Idaho, Kansas, Minnesota, Montana, Nebraska, Nevada, North Dakota, Oregon, South Dakota, Utah, Washington and Wyoming, as of 2023. In Australia, all states allow it to control wild oats and most allow its broader use in combination with

. It is used in the United Kingdom, Morrocco and the EU states of Belgium, France, Ireland and the Netherlands.

Application

It is incorporated to soil pre-sowing or (IBS) incorporated by sowing, and is applied immediately before or up to 3 weeks before sowing. It is recommended to incorporate it 2–4 cm deep, and within 6 hours if the soil is moist, or 24 hours if dry, to minimise volatilisation. Proper incorporation is essential for efficacy, and two-pass incorporation is needed for maximum efficacy. Efficacy can also be reduced if the top 2 cm of soil is very dry. Tri-allate is applied at 0.8-1.0 kg/Ha (0.71-0.89 lbs/ac) in Australia, with a spraywater volume of 30 to 100 L/Ha (3.2-10.7 US gal/ac). Triallate is sold as an emulsifiable concentrate of 500 g/L active ingredient.

Compatibility

Tri-allate is compatible with spray mixes containing

chlorsulfuron Chlorsulfuron is an Acetolactate synthase inhibitor, ALS (acetolactate synthase) inhibitor herbicide, and is a sulfonylurea compound. It was discovered by George Levitt in February 1976 while working at E. I. du Pont de Nemours and Company, DuPo ...

, diclofop-methyl,

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 ...

and

oryzalin Oryzalin is a herbicide of the dinitroaniline class. It acts through the disruption ( depolymerization) of microtubules, thus blocking anisotropic growth of plant cells. It can also be used to induce polyploidy in plants as an alternative to co ...

Crops applied to

Tri-allate is applied to

wheat Wheat is a group of wild and crop domestication, domesticated Poaceae, grasses of the genus ''Triticum'' (). They are Agriculture, cultivated for their cereal grains, which are staple foods around the world. Well-known Taxonomy of wheat, whe ...

triticale Triticale (; × ''Triticosecale'') is a hybrid of wheat (''Triticum'') and rye (''Secale'') first bred in laboratories during the late 19th century in Scotland and Germany. Commercially available triticale is almost always a second-generation ...

chickpea The chickpea or chick pea (''Cicer arietinum'') is an annual plant, annual legume of the family (biology), family Fabaceae, subfamily Faboideae, cultivated for its edible seeds. Its different types are variously known as gram," Bengal gram, ga ...

barley Barley (), a member of the grass family, is a major cereal grain grown in temperate climates globally. It was one of the first cultivated grains; it was domesticated in the Fertile Crescent around 9000 BC, giving it nonshattering spikele ...

pea Pea (''pisum'' in Latin) is a pulse or fodder crop, but the word often refers to the seed or sometimes the pod of this flowering plant species. Peas are eaten as a vegetable. Carl Linnaeus gave the species the scientific name ''Pisum sativum' ...

linseed Flax, also known as common flax or linseed, is a flowering plant, ''Linum usitatissimum'', in the family Linaceae. It is cultivated as a food and fiber crop in regions of the world with temperate climates. In 2022, France produced 75% of the ...

lupin ''Lupinus'', commonly known as lupin, lupine, or regionally bluebonnet, is a genus of plants in the legume family Fabaceae. The genus includes over 199 species, with centres of diversity in North and South America. Smaller centres occur in No ...

canola file:CanolaBlooms.JPG, Close-up of canola blooms file:Canola Flower.jpg, Canola flower Rapeseed oil is one of the oldest known vegetable oils. There are both Edible oil, edible and industrial forms produced from rapeseed, the seed of several ...

faba bean ''Vicia faba'', commonly known as the broad bean, fava bean, or faba bean, is a species of vetch, a flowering plant in the pea and bean family Fabaceae. It is widely cultivated as a crop for human consumption, and also as a cover crop. Vari ...

s and

safflower Safflower (''Carthamus tinctorius'') is a highly branched, herbaceous, thistle-like annual plant in the family Asteraceae. It is one of the world's oldest crops; today, it is commercially cultivated for vegetable oil extracted from the seeds. ...

. It was used on canary grass, but this registration was not renewed by the manufacturers, circa 2000.

Weeds controlled

Tri-allate is used to control wild oats,

annual ryegrass Annual ryegrass is a common name for several species of ryegrass ''Lolium'' is a genus of tufted grasses in the bluegrass subfamily (Pooideae). It is often called ryegrass, but this term is sometimes used to refer to grasses in other genera. ...

, wireweed,

phalaris Phalaris () was the tyrant of Akragas (now Agrigento) in Sicily in Magna Graecia, from approximately 570 to 554 BC. History Phalaris was renowned for his excessive cruelty. Among his alleged atrocities is cannibalism: he was said to have eaten ...

spp,

fumitory ''Fumaria'' (fumitory or fumewort, from Latin ', "smoke of the earth") is a genus of about 60 species of annual flowering plants in the family Papaveraceae. The genus is native to Europe, Africa and Asia, most diverse in the Mediterranean re ...

, cereal oats, sand fescue, silvergrass, wintergrass, paradoxa grass (canary grass), corn gromwell (sheepweed) and rough poppy. It supresses brome grass, barleygrass, cornered jack (doublegee),

caltrop A caltrop (also known as caltrap, galtrop, cheval trap, galthrap, galtrap, calthrop, jackrock or crow's foot''Battle of Alesia'' (Caesar's conquest of Gaul in 52 BC), Battlefield Detectives program, (2006), rebroadcast: 2008-09-08 on History C ...

(yellowvine & bullhead), yellow burr weed,

deadnettle ''Lamium'' (dead-nettles) is a genus of about 30 species of flowering plants in the family Lamiaceae, of which it is the type genus. They are all herbaceous plants native to Eurasia and northern Africa, with several widely naturalised across muc ...

and speedwell.

Tradenames

Triallate has been sold as ''Avadex'', ''Buckle'', ''Far-Go'', ''Showdown'', ''Check Mate'', ''Triallate Gold'', ''Triallate'' and ''Tri-Allate''.

References

Links

* {{Herbicides Group 15 herbicides Thiocarbamates Diisopropylamino compounds Organochlorides