Tepraloxydim

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Chemical Identification | General Product Information | Physical & Safety Data

Chemical Identification

Common Name

Tepraloxydim

中文通用名

吡喃草酮

IUPAC

(5RS)-2-{(EZ)-1-[(2E)-3-chloroallyloxyimino]propyl}-3-hydroxy-5-perhydropyran-4-ylcyclohex-2-en-1-one

CAS

2-[1-[[[(2E)-3-chloro-2-propenyl]oxy]imino]propyl]-3-hydroxy-5-(tetrahydro-2H-pyran-4-yl)-2-cyclohexen-1-one

CAS No.

149979-41-9

Molecular Formula

C₁₇H₂₄ClNO₄

Molecular Structure

General Product Information

Category

Herbicides > Cyclohexene oxime herbicides

Activity

Herbicide

Uptake of the product by absorption into the leaves occurs faster for younger leaves and is enhanced by high temperatures and humidity, and the addition of an adjuvant. The product is then translocated throughout the plant to the roots. Within a few days of application, growth of treated grasses stops, with young and active tissues affected first. Within 3 - 4 weeks, leaf tip necrosis, reddening of foliage and dieback occurs. The leaf sheaths turn brown and soft at and above their point of attachment to the node.

At the proposed use rates of 50-75 g/ha, tepraloxydim provides excellent post-emergence control of annual grasses e.g. Alopecurus myosuroides, Avena fatua, Brachiaria plantaginea, Digitaria sanguinalisand Echinochloa crus-galli. The activity is increased by addition of an adjuvant such as Dash HC oil concentrate. Higher rates of 75-100 g/ha are required to provide control of Poa annua and volunteer corn. Control of perennial grasses (Sorghum halepense, Agropyron repens) can be achieved at 100 g/ha.

Aramo is compatible with grass herbicides such as Verdict, Shogun, Targa and Fusion, and can be tank mixed with Fastac Duo, omethoate, Talstar, deltamethrin and chlorpyrifos.

Studies were conducted (BCPC 1999) with a range of blackgrass (Alopecurus myosuroides) populations exhibiting differing degrees of herbicide resistance.Target-site resistance (insensitive ACCase) reduced the efficacy of tepraloxydim but the proposed field rate of 50 g/ha remained effective (> 83% control) with all blackgrass populations. In addition, the efficacy of tepraloxydim under these conditions was more stable than other ACCase inhibitors tested. In the same study, there was no evidence that tepraloxydim efficacy was adversely affected by increased metabolic activity in resistant biotypes.

Field trials in Brazil (1995-1999) showed that tepraloxydim provided good control of annual grasses including Cenchrus echinatus, Digitaria horizontalis, Eleusine indicaand Pennisetum setosum at 75 g/ha with good selectivity to cotton, dry beans and soybean at 100 g/ha. The efficacy was not affected by location, climatic conditions or growth stage of the crop. However, the higher rate of 100 g/ha plus adjuvant was required to assure good control of the weeds under dry conditions and with plants exceeding the mid-tillering growth stage.

Field trials conducted in the Prairie Provinces in Canada on canola, flax, dry peas and lentils showed a good control of green foxtail (Setaria viridis), volunteer barley (Hordeum vulgare), volunteer wheat (Triticum aestivum) and quackgrass (Agropyron repens).

BAS 620H is well tolerated by the Lily family and Pinus species.

In the UK, applications are prohibited between November 1^st and March 31^st for linseed, sugar beet and fodder beet; and between November 1^st and 1^st March for field bean, combining pea, vining pea, leek, bulb onion, carrot, cabbage and cauliflower. The recommended application rate is 1 - 2 L/ha with a maximum of one application per year.

Tepraloxydim can be used alone or in a mixture with other herbicides to increase the spectrum of broadleaf weeds controlled. However, control of grasses is not as extensive when BAS 620H is tank mixed with post-emergence soybean broadleaf herbicides, in particular bentazone; in these cases, activity is improved by using BAS 620H at higher rates and with ammonium sulfate or urea ammonium nitrate used in addition to oil concentrates. BAS 620H is rainfast within an hour.

CropUse

CropUses:
alfalfa, beans, beets, broccoli, Brussels sprouts, cabbage, canola, carrot, cauliflower, chard, clover, cotton, cucumber, dry beans, flax, garlic, kale, kohlrabi, leek, lentils, lettuce, linseed, mustard, oilseed rape, okra, onion, peanuts, peas, peppers, potatoes, radishes, safflower, soybeans, spinach, squash, sugar beet, sunflower, tomatoes, turnip

50-100 g ai/ha (EU)
50-140 g ai/ha (US)

Premix

Type	AI concⁿ
Emulsifiable concentrate (EC)	20% (Neto)
Emulsifiable concentrate (EC)	5% w/v (Aramo)

Physical & Safety Data

Physical Properties

Molecular weight:341.8; Physical form:White, odourless powder. Melting point:74 °C; Vapour pressure:1.1 ×10-2 mPa (20 °C); pKa:4.58 (20 °C); Solubility:In pure water 0.43 g/l (20 °C).;

Toxicology

Oral:Acute oral LD₅₀ for rats c. 5000 mg/kg. Percutaneous:Acute percutaneous LD₅₀ for rats >2000 mg/kg. Non-irritating to skin and mucous membranes (rabbits); not a skin sensitiser (guinea pigs). Inhalation:LC₅₀ (4 h) for rats >5.1 mg/l.

Environmental Profile

Ecotoxicology:
Algae: EC₅₀ (72 h) for Chlorella fusca 76 mg/l.Bees: LD₅₀ (oral and contact) >200 µg/bee.Birds:LD₅₀ for quail >2000 mg/kg.Daphnia: EC₅₀ (48 h) >100 mg/l.Fish: LC₅₀ (96 h) for rainbow trout >100 mg/l.Worms: LC₅₀ (14 d) for Eisenia foetida >1000 mg/kg soil.Other aquatic spp.:EC₁₀ (17 h) for Pseudomonas putida >1000 mg/l.

Environmental fate:
Soil:Soil DT₅₀ (lab.) 1-9 d. Photolytic DT₅₀ on soil surface c. 1 d.

Quail	LD₅₀ >2,000 mg/kg
Algae _{[72 h]}	EC₅₀ 76 mg/L
Trout _{[96 h]}	LC₅₀ 100 mg/L
Daphnia_{[48 h]}	EC₅₀100 mg/L
Bee _[contact]	LD₅₀ >200 μg/bee

Fate in soil:
Under laboratory conditions, tepraloxydim has a half-life in aerobic soil of 1-9 days and a DT₉₀ in sandy loam of 17-28 days. Tepraloxydim is classified as moderately persistent in soils under aerobic conditions. Five major metabolites were identified from the laboratory studies.
In field dissipation studies in Canada, tepraloxydim was rapidly degraded with DT₅₀ of 3-12 days and DT₉₀ of 31-76 days. No parent residues were detected 30 days after application; tepraloxydim shows little potential for carry-over. One of the two metabolites identified in the field trials was classified as persistent (DT₅₀ of 198-235 days). No residues were detected below 5 cm in the soil profiles from the Canadian trials; the parent and metabolites show little potential for leaching to groundwater.
Photolysis is rapid on the surface of loamy sand soil (DT₅₀ approximately 1 day under laboratory conditions).
Tepraloxydim is highly to very highly mobile in sand, sandy loam, loamy sand, loam and clay soils (K_d = 0.011 - 1.5; K_oc = 3.7 - 77.2). Due to the rapid degradation and low use rates, leaching to groundwater is unlikely. The major soil metabolites are classified as moderately to very highly mobile in soils (K_oc = 0.35 - 1104)
Phototransformation, biotransformation and hydrolysis in acidic conditions are the main routes of transformation of tepraloxydim.

Fate in aquatic systems:
Phototransformation (t_1/2= 0.7 days at pH 5, 1.6 days at pH 7-9) is a significant route of transformation of tepraloxydim in aquatic environments.
Hydrolysis is slow under neutral or basic conditions, but faster at acidic pH (t_1/2= 3.5 - 24.4 days).
The half life of tepraloxydim in anaerobic flooded soils under laboratory conditions is 3.2 months, with a DT₉₀ of 10.5 months; the product is classified as moderately persistent. Half lives in the soil and water phases were 3 and 3.2 months, respectively. In aerobic conditions, the half life in flooded sandy loam was 48.6 days and 171.4 days in flooded sand. Half lives in the water phases were 41 and 129 days, respectively.

Transport Information

Hazard Class:O (Obsolete as pesticide, not classified)