Carfentrazone-ethyl

Carfentrazone-ethyl

唑草酮

ethyl (RS)-2-chloro-3-{2-chloro-5-[4-(difluoromethyl)-4,5-dihydro-3-methyl-5-oxo-1H-1,2,4-triazol-1-yl]-4-fluorophenyl}propionate

ethyl α,2-dichloro-5-[4-(difluoromethyl)-4,5-dihydro-3-methyl-5-oxo-1H-1,2,4-triazol-1-yl]-4-fluorobenzenepropanoate

128639-02-1

C₁₅H₁₄Cl₂F₃N₃O₃

Herbicides > Triazolone herbicides

Herbicide.
Carfentrazone-ethyl is a post-emergence, contact herbicide for application to actively growing weeds. It causes desiccation of leaves resulting in visible injury within 24 hours and plant death within 2-5 days. Temperature has no effect on the herbicide's activity and it becomes rainfast within one hour. The product has no residual soil activity. Carfentrazone-ethyl is selective to small-grain cereals but has shown phytotoxicity to cotton, potatoes, sunflowers and sugar beet. Rotational crops are, however, not damaged by the product. Carfentrazone-ethyl is active against sulfonylurea-resistant Kochia species. The use of adjuvants improves the level of weed control. The product has been shown to be safe when used in combination with most other herbicides.

Carfentrazone-ethyl is safe to cereal crops at the application rates required for activity. Selectivity in maize and soybeans requires early application to avoid temporary crop injury such as stunting and chlorosis. In soybeans, the product is recommended for use as a rapid burn down treatment in combination with residual herbicides. The herbicide has weaker activity on large weeds; a range of combination products has been developed to overcome this.

In the US, carfentrazone-ethyl is approved for use as a herbicide and defoliant for use on cotton prior to harvest. The product can be tank mixed with other harvest aids such as ethephon to assist boll opening or thiadiazuron for enhanced defoliation and regrowth inhibition.

Results from weed control trials across the US cotton belt (SWSS, 2001) showed significant activity from post-directed applications of Aim, alone or in combination with other post-emergence cotton products. Applied alone, Aim provided excellent control of morningglory (Ipomoea spp) and lanceleaf sage (Salvia reflexa). In combination with Roundup Ultra (glyphosate), Aim provided enhanced control of spurred anoda (Anoda cristata), morningglory, hemp sesbania (Sesbania exaltata) and sicklepod (Cassia obtusifolia); the speed of action was also increased. In combination with Buctril (bromoxynil), Aim gave enhanced control of spurred anoda and morningglory with faster burndown effect. The addition of Staple (pyrithiobac) to Aim resulted in more stable control of morningglory under dry conditions where Staple may not perform well.

An evaluation of carfentrazone applied alone or in combination with other herbicides for weed control in grain sorghum was reported at the annual meeting of the Western Society of Weed Science in 2002.

Trials in 1997-1998 in rice in the US (SWSS, 1999) showed good control by early post-emergence applications of carfentrazone of morningglory species: entireleaf and ivyleaf (Ipomoea hederacea); palmleaf (I wrightii); and pitted (I lacunosa). It was also effective against hemp sesbania, Pennsylvania smartweed (Polygonum pensylvanicum), texasweed (Caperonia palustrius) and redweed (Melochia corchorifolia). Good selectivity to rice was noted.

Applications to rice in California are limited to ground applications because of the risk to neighbouring crops through spray drift from aerial spray operations. FMC has been conducting studies at early post-seeding through to 20-45 days post-seeding with direct dry applications (DDA) and direct stream applications (DSA) to identify the safest means to apply Shark in California (see WSWS, 2002). Results from trials performed from 1999-2001 indicated that aerial DDA and aerial or ground DSA treatments at the early post-seeding timing provided excellent control of broadleaved weeds and sedges while minimising the risk to off-target crops that are frequently cultivated adjacent to the rice paddies in California. FMC has applied for US approval for these application methods of Shark in rice.

Carfentrazone-ethyl was applied alone or in mixture with a range of herbicides pre-flooding (+ bentazon, triclopyr, bispyribac-sodium, bensulfuron, propanil, halosulfuron) or post-flooding (+ 2,4-D amine) to rice in Arkansas (Arkansas Agricultural Experiment Station, 2004). There was no crop damage or differences in yield between treatments. All treatments gave good to excellent season long control of Echinochloa crus-galli. Control of Sesbania exaltata was less effective when mixtures included bispyribac-sodium or triclopyr, which seemed to be antagonistic. Control of Ipomoea lacunosa was excellent except from the propanil mix. Control of Aeschynomene virginica was generally more moderate.

Quicksilver can be applied to newly seeded or established turf (Kentucky bluegrass, perennial ryegrass, fescues, creeping bentgrass, bermudagrass, bahiagrass, zoysiagrass, St Augustinegrass and centipededgrass) in the US. The product controls a wide range of broadleaved weeds including: white clover, ground ivy, dandelion, catchweed bedstraw, plantains, corn speedwell, spotted spurge, virginia buttonweed and purslane. It may be tank-mixed with other herbicides for an increased spectrum of weed control.

In Australia, carfentrazone (as Hammer) is approved for burndown weed control in tank-mix combinations with glyphosate, atrazine, triasulfuron, pendimethalin, simazine and trifluralin. Good control has been reported of difficult weeds including common storksbill (Erodium cicutarium), wild radish (Raphanus raphanistrum), double gee (Emex australis), capeweed (Arctotheca calendula), Paterson's curse (Echium plntagineum), stonecrop (Crassula spp) and marshmallow (Malva parviflora). The product is approved for use in pre-plant burndown situations, for pre-flowering vines, tree fruits and nuts and for industrial weed control (around commercial buildings).

Field trials in Italy showed that a tank mixture of carfentrazone-ethyl plus Granstar (tribenuron-methyl) provided excellent control in cereals of a wide range of broadleaved weeds including Amaranthus retroflexus, Bifora radians, Capsella bursa-pastoris, Cyperus esculentus, Chenopodium album, Lamium purpureum, Mercurialis annua, Papaver rhoeas, Polygonum persicaria, P convolvulus, Sinapis arvesis and Solanum nigrum.

In UK potato crops, the Shark formulation of carfentrazone-ethyl is recommended to be sprayed just before crop emergence and tank-mixed with a residual herbicide (eg metribuzin, linuron, clomazone, or pendimethalin) (Farmers Weekly, 2003). Applications of Spotlight to desiccate potato foliage (ware and seed potatoes) in the UK must be made at least seven days before harvest. Spotlight can be used in a flail and chemical programme on seed potatoes. A two application sequence is approved on ware crops. Spotlight can be used regardless of soil moisture and should always be applied with an oil adjuvant (Belchim newsletter, 2004).

Crop uses:
acerolas, almond hulls, avocados, atemoyas, bananas, barley, biridas, borage, brassicas, cactus, caneberries, canistels, cereals, cherimoyas, citrus, coconuts, coffee, cotton, custard apples, curcubits, feijoa, fig, fish, flax, forage, fodder, grapefruit, grapes, guavas, hay, hops, horseradish, jaboticas, Juneberries, kava, kiwi fruits, legumes, lingonberries, lychees, longans, maize, mangos, mulberries, mustard seeds, oats, okra, olives, palm heart leaves, passion fruits, papaya, pawpaw, peanuts, persimmon, pistachios, pome fruits, pomegranates, potatoes, pulasans, pummelos, rambutans, rape seeds, rice, root vegetables, tuber vegetables, rye, safflowers, salal, sapodillas, sapotes, shellfish, sorghum, soybeans, Spanish lime, star apples, star fruits, stone fruits, strawberries, stevia, sugar apples, sugar cane, sunflowers, tea, tree nuts, triticale, turf, corm vegetables, vanilla, vines, wheat

Maize: 4-17 g ai/ha	Rice: 15-112 g ai/ha
Grain sorghum: 10 g ai/ha	Wheat: 12-26 g ai/ha

Tribenuron-methyl+carfentrazone-ethyl
Tribenuron Methyl+Carfentrazone-ethyl+Fluroxypyr-meptyl
Quinclorac+Carfentrazone-ethyl+Pyrazosulfuron-ethyl
Pyrazosulfuron-ethyl+MCPA-sodium+Carfentrazone-ethyl
Penoxsulam+Carfentrazone-ethyl+Cyhalofop-butyl
Metsulfuron-methyl+carfentrazone-ethyl
MCPA-sodium+Carfentrazone-ethyl+Florasulam
MCPA-sodium+Carfentrazone-ethyl
MCPA-isooctyl+Florasulam+Carfentrazone-ethyl
Fluroxypyr-meptyl+Carfentrazone-ethyl+Florasulam
Fluroxypyr+carfentrazone-ethyl
Flucarbazone-Na+Carfentrazone-ethyl
Clodinafop-propargyl+Carfentrazone-ethyl+Fluroxypyr-meptyl
Carfentrazone-ethyl+quinclorac
Carfentrazone-ethyl+Florasulam
carfentrazone-ethyl+chlorimuron-ethyl
Carfentrazone-ethyl+Bispyribac-sodium
Bentazone+carfentrazone-ethyl
Bensulfuron-methyl+carfentrazone-ethyl+clodinafop-propargyl
Bensulfuron-methyl+carfentrazone-ethyl

Type	AI concn
Water-dispersible granule (WG)	50% (w/w)
	40% (w/w)
Emulsifiable concentrate (EC)	24% (w/v)
?	40% (w/v)
Oil-in-water emulsion	6% (w/v)

Dry flowable.?
Premix Parters: MIPC; prochloraz;

Molecular weight:412.2; Physical form:Viscous yellow liquid. Density:1.457 (20 °C); Melting point:-22.1 °C; Flash point:>110 °C;Boiling point: 350-355°C at 760 mm Hg; Vapour pressure:1.6 ×10-2 mPa(25 °C); Henry constant:2.47×10-4 Pa m3 mol-1 (20 °C, calc.); Partition coefficient(n-octanol and water):logP = 3.36; Solubility:In water 12 mg/ml (20 °C), 22 mg/ml (25 °C), 23 mg/ml (30 °C). In toluene 0.9, hexane 0.03 (both in g/ml, 20 °C); miscible with acetone, ethanol, ethyl acetate and methylene chloride.; Stability:Hydrolytic DT50 3.6 h (pH 9), 8.6 d (pH 7), stable (pH 5). Aqueous photolytic DT50 8 d.;

Oral:Acute oral LD₅₀ for female rats 5143 mg/kg. Percutaneous:Acute percutaneous LD₅₀ for rats >4000 mg/kg. Minimally irritating to eyes and non-irritating to skin (rabbits). No skin sensitisation (guinea pigs). Inhalation:LC₅₀ (4 h) for rats >5.09 mg/l. Phytotoxicity:Good tolerance in wheat, barley and rice. ADI:0.01 mg/kg.?

Ecotoxicology: Algae:EC₅₀12-18 mg/l, depending on species.Bees:LD₅₀ (oral) >35; (contact) >200 mg/bee.Birds: LD₅₀ for quail >1000 mg/kg. LC₅₀ for quail and ducks >5000 ppm.Daphnia:EC₅₀ (48 h) 9.8 mg/l.Fish:LC₅₀(96 h) 1.6-43 mg/l, depending on species,LC50 1.6 mg/l (96 h)(rainbow trout),2.0 mg/l (96 h) (bluegill).Worms:LC₅₀ >820 mg/kg soil.Other aquatic spp.:EC₅₀(96 h) for eastern oyster 2.05, mysid shrimp 1.16 ppm.Dietary LC50 (8 day) >5620 ppm (mallard, bobwhite quail). Environmental fate: Animals:In rats, c. 80% of the administered dose is rapidly absorbed and excreted in the urine within 24 h. The major metabolite was the corresponding acid. Further metabolism appears to involve oxidative hydroxylation of the methyl group or dehydrochlorSoil:Broken down in the soil by microbial action; not susceptible to photodecomposition nor volatility following soil application. Strongly adsorbed to sterile soils (K_oc 750 at 25 °C). In non-sterile soils, rapidly converted to tPlant:Rapidly converted to the free acid, which is hydroxylated and then oxidised at the triazolinone methyl to form the dibasic acid; DT₅₀ (carfentrazone-ethyl) <7 d, DT₅₀ (carfentrazone) <28 d.?

Rainbow trout [96 h]	LC50 1.6 mg/L Mallard duck LD50>2,250 mg/kg
Bluegill sunfish [96 h]	LC50 2.0 mg/L Bobwhite quail LD50 >2,250 mg/kg
Eastern oyster [96 h]	LC50/EC502.05 mg/L Daphnia [48 h] LC50 >9.8 mg/L
Mysid shrimp [96 h]	LC50/EC501.16 mg/L Green alga EC50 15 mg/L
Aquatic crustaceans	LC50 1.17 mg/L Earthworms LC50 >820 mg/kg

Fate in :

Carfentrazone is classed as practically non-toxic to mallard duck and bobwhite quail on an acute and sub-acute basis. It is moderately toxic to rainbow trout, bluegill sunfish, eastern oyster and mysid shrimp. It is highly toxic to aquatic plants.

Fate in soil:
Carfentrazone-ethyl is primarily degraded by microbes; soil half-life (field) = 2-5 days.
Aerobic soil metabolism half-life = 1.3 days
Anaerobic soil metabolism half-life = 0.3 - 0.8 days
Carfentrazone-ethyl is immobile in loamy-sand, sandy clay loam and silt loam soils

Fate in aquatic systems:
The photolytic half-life in water is 8.3 days.
Hydrolysis; half-life at pH 5 = stable, at pH 7 = 8.6 days, at pH 9 = 3.6 hours
Carfentrazone-ethyl breaks down rapidly in the environment and the metabolites are persistent in terrestrial and aquatic systems. With its low application rate, low residue levels are expected in surface water and groundwater but are not expected to trigger acute or chronic risk levels for non-target plants or animals.?
WATER SOLUBILITY: 12 μg/ml at 20°C, 22 μg/ml at 25°C, 23 μg/ml at 30°C.

Hazard Class:III (Slightly hazardous)