Halauxifen-methyl (Ref: DE-729)

Halauxifen-methyl (Ref: DE-729)	Last updated: 25/05/2025
(Also known as: XDE 729; XR 729; halauxiphen-methyl)

SUMMARY

Data alerts

The following alerts are based on the data in the tables below. An absence of an alert does not imply the substance has no implications for human health, biodiversity or the environment but just that we do not have the data to form a judgement.

Environmental fate	Ecotoxicity	Human health
Environmental fate Moderate alert: Moderately persistent; Drainflow: Slightly mobile; Potential for particle bound transport: Medium	Ecotoxicity Moderate alert: Birds chronic ecotoxicity: Moderate; Fish acute ecotoxicity: Moderate; Fish chronic ecotoxicity: Moderate; Daphnia acute ecotoxicity: Moderate; Daphnia chronic ecotoxicity: Moderate; Bees acute contact ecotoxicity: Moderate; Earthworms acute ecotoxicity: Moderate; Earthworms chronic ecotoxicity: Moderate	Human health High alert: Reproduction/development effects

GENERAL INFORMATION

Description

A picolinic acid herbicide for use on cereals, rice and other crops the control of broadleaved weeds

Example pests controlled

Broadleaved weeds

Example applications

Wheat; Barley

Efficacy & activity

Availability status

Introduction & key dates

2014, Introduced

GB regulatory status

GB COPR regulatory status

Approved

Date COPR inclusion expires

05/08/2031

GB LERAP status

Check label - may vary with formulation

EC Regulation 1107/2009 (repealing 91/414)

EC Regulation 1107/2009 status

Approved

Dossier rapporteur/co-rapporteur

United Kingdom/France

Date EC 1107/2009 inclusion expires

05/01/2028

EU Candidate for substitution (CfS)

Listed in EU database

Yes

Approved for use (✓) under EC 1107/2009 in the following EU Member States

ATAustria	BEBelgium	BGBulgaria	CYCyprus	CZCzech Republic	DEGermany	DKDenmark	EEEstonia	ELGreece
✓	✓	✓		✓	✓	✓	✓
ESSpain	FIFinland	FRFrance	HRCroatia	HUHungary	IEIreland	ITItaly	LTLithuania	LULuxembourg
✓	✓	✓		✓	✓	✓	✓	✓
LVLatvia	MTMalta	NLNetherlands	PLPoland	PTPortugal	RORomania	SESweden	SISlovenia	SKSlovakia
✓		✓	✓	✓	✓	✓	✓	✓

Approved for use (✓) under EC 1107/2009 by Mutual Recognition of Authorisation and/or national regulations in the following EEA countries

ISIceland	NONorway
	✓

Additional information

Also used in

Canada; USA; Morocco

Chemical structure

Isomerism

None

Chemical formula

C₁₄H₁₁Cl₂FN₂O₃

Canonical SMILES

COC1=C(C=CC(=C1F)C2=NC(=C(C(=C2)N)Cl)C(=O)OC)Cl

Isomeric SMILES

International Chemical Identifier key (InChIKey)

KDHKOPYYWOHESS-UHFFFAOYSA-N

International Chemical Identifier (InChI)

InChI=1S/C14H11Cl2FN2O3/c1-21-13-7(15)4-3-6(11(13)17)9-5-8(18)10(16)12(19-9)14(20)22-2/h3-5H,1-2H3,(H2,18,19)

2D structure diagram/image available?

Yes

General status

Pesticide type

Herbicide

Substance groups

Picolinic acid herbicide; Pyridine herbicide

Minimum active substance purity

930 g kg⁻¹

Known relevant impurities

Substance origin

Synthetic

Mode of action

Synthetic auxin

CAS RN

943831-98-9

EC number

695-056-1

CIPAC number

970.201

US EPA chemical code

PubChem CID

16656802

CLP index number

No data found

Molecular mass

345.16

PIN (Preferred Identification Name)

methyl 4-amino-3-chloro-6-(4-chloro-2-fluoro-3-methoxyphenyl)pyridine-2-carboxylate

IUPAC name

methyl 4-amino-3-chloro-6-(4-chloro-2-fluoro-3-methoxyphenyl)pyridine-2-carboxylate

CAS name

methyl 4-amino-3-chloro-6-(4-chloro-2-fluoro-3-methoxyphenyl)-2-pyridinecarboxylate

Other status information

Relevant Environmental Water Quality Standards

Herbicide Resistance Class (HRAC MoA class)

Herbicide Resistance Class (WSSA MoA class)

Insecticide Resistance Class (IRAC MoA class)

Not applicable

Fungicide Resistance Class (FRAC MOA class)

Not applicable

Examples of recorded resistance

Physical state

White powdery solid

Related substances & organisms

halauxifen

Formulations

Property

Value

Example manufacturers & suppliers of products using this active now or historically

Dow Agrosciences

Example products using this active

Arylex Active
Belkar
Korvettol
Pixxaro EC

Formulation and application details

Usually supplied as an emuslifiable concentrate to use as a broadcasted foliar spray

ENVIRONMENTAL FATE

Property

Value

Source; quality score; and other information

Interpretation

Solubility - In water at 20 °C (mg l⁻¹)

1830

High

Solubility - In organic solvents at 20 °C (mg l⁻¹)

38.1

Methanol

250

Acetone

129

Ethyl acetate

9.83

n-Octanol

Melting point (°C)

145.5

Boiling point (°C)

Decomposes before boiling

Degradation point (°C)

222

Flashpoint (°C)

Octanol-water partition coefficient at pH 7, 20 °C

5.75 X 10⁰³

Calculated

Log P

3.76

High

Fat solubility of residues

Solubility

Data type

Density (g ml⁻¹)

Dissociation constant pKa) at 25 °C

2.84

Vapour pressure at 20 °C (mPa)

5.9 X 10^-06

Low volatility

Henry's law constant at 25 °C (Pa m³ mol⁻¹)

1.22 X 10^-06

Non-volatile

Volatilisation as max % of applied dose lost

From plant surface

From soil surface

Maximum UV-vis absorption L mol⁻¹ cm⁻¹

Neutral: 212nm=16401, 249nm=18956
Acidic: 215nm=22496, 256nm=13770
Basic: 212nm=19023, 247nm=21979

Surface tension (mN m⁻¹)

72.5

Degradation

Property

Value

Source; quality score; and other information

Interpretation

General biodegradability

Soil degradation (days) (aerobic)

DT₅₀ (typical)

1.3

Non-persistent

DT₅₀ (lab at 20 °C)

1.3

Non-persistent

DT₅₀ (field)

Moderately persistent

DT₉₀ (lab at 20 °C)

7.2

Non-persistent

DT₉₀ (field)

144

DT₅₀ modelling endpoint

Note

EU dossier lab studies DT₅₀ range 0.9-2.0, DT₉₀ range 3.0-16.3; Field studies DT₅₀ range 2.1-43 days, DT₉₀ range 49-144 days

Dissipation rate RL₅₀ (days) on plant matrix

Value

Note

Dissipation rate RL₅₀ (days) on and in plant matrix

Value

Note

Aqueous photolysis DT₅₀ (days) at pH 7

Value

0.001

Fast

Note

Very rapid - 4-7 minutes

Aqueous hydrolysis DT₅₀ (days) at 20 °C and pH 7

Value

155

at 27 °C pH 7

Persistent

Note

Highly variable with pH and temperature.

Water-sediment DT₅₀ (days)

1.8

Fast

Water phase only DT₅₀ (days)

1.8

Moderately fast

Sediment phase only DT₅₀ (days)

Air degradation

As this parameter is not normally measured directly, a surrogate measure is used: ‘Photochemical oxidative DT₅₀’. Where data is available, this can be found in the Fate Indices section below.

Decay in stored produce DT₅₀

Soil adsorption and mobility

Property

Value

Source; quality score; and other information

Interpretation

Linear

K_d (mL g⁻¹)

72.7

Slightly mobile

K_oc (mL g⁻¹)

1417

Notes and range

EU dossier K_d range 13-340 mL g⁻¹, K_oc range 473-2659 mL g⁻¹, soils=7

Freundlich

K_f (mL g⁻¹)

Slightly mobile

K_foc (mL g⁻¹)

995

¹/_n

0.87

Notes and range

EU dossier kf range 8-310 mL g⁻¹, K_foc range 190-1812 mL g⁻¹, ¹/_n range 0.76-0.98, soils=7

pH sensitivity

Yes but weak

Fate indices

Property

Value

Source; quality score; and other information

Interpretation

GUS leaching potential index

1.64

Calculated

Low leachability

SCI-GROW groundwater index (μg l⁻¹) for a 1 kg ha⁻¹ or 1 l ha⁻¹ application rate

Value

4.71 X 10^-02

Calculated

Note

Potential for particle bound transport index

Medium

Calculated

Potential for loss via drain flow

Slightly mobile

Calculated

Photochemical oxidative DT₅₀ (hrs) as indicator of long-range air transport risk

52.8

Calculated using the Atkinson method. Assumed 1.5E+06 OH/cm³, 12 hr

Substance of concern for long-range air transport

Bio-concentration factor

BCF (l kg⁻¹)

217

Threshold for concern

CT₅₀ (days)

1.6

Known soil metabolites

Metabolite

Major/Minor fraction

$Click here for further information on Major/Minor fraction$

Estimated maximum occurrence fraction

Notes

halauxifen (Ref: X11393729)

Major fraction

0.727

4-amino-3-chloro-6-(4-chloro-2-fluoro-3-hydroxyphenyl)pyridine-2-carboxylic acid (Ref: X11449757)

Major fraction

0.174

methyl 4-amino-3-chloro-6-(4-chloro-2-fluoro-3-hydroxyphenyl)pyridine-2-carboxylate (Ref: X11406790)

Known groundwater metabolites

None

Other known metabolites

Metabolite name and reference

Aliases

Formation medium / Rate

Estimated maximum occurrence fraction

methyl 4-amino-3-chloro-6-(4-chloro-2-fluoro-3-hydroxyphenyl)pyridine-2-carboxylate (Ref: X11406790)

Surface water; Sediment

ECOTOXICOLOGY

Terrestrial ecotoxicology

Property

Value

Source; quality score; and other information

Interpretation

Mammals - Acute oral LD₅₀ (mg kg⁻¹)

> 5000

Rat

Low

Mammals - Short term dietary NOEL

(mg kg⁻¹)

(ppm diet)

Mammals - Chronic 21d NOAEL (mg kg⁻¹ bw d⁻¹)

443

Unknown species Reproductive NOAEL

Low

Birds - Acute LD₅₀ (mg kg⁻¹)

> 2250

Colinus virginianus

Low

Birds - Short term dietary (LC₅₀/LD₅₀)

Birds - Chronic 21d NOEL (mg kg⁻¹ bw d⁻¹)

36.9

Colinus virginianus NOAEL

Moderate

Earthworms - Acute 14 day LC₅₀ (mg kg⁻¹)

> 500

Eisenia foetida corr

Moderate

Earthworms - Chronic NOEC, reproduction (mg kg⁻¹)

5.0

Eisenia foetida corr

Moderate

Soil micro-organisms

Nitrogen mineralisation: No significant adverse effect
Carbon mineralisation: No significant adverse effect

Dose: 0.05 mg kg⁻¹ soil 28 Day

Collembola

Acute LC₅₀ (mg kg⁻¹)

Chronic NOEC (mg kg⁻¹)

500

Folsomia candida corr

Non-target plants

0.4

Soybean Carrot
Vegetative vigour, ER₅₀
as g ha⁻¹

0.417

Soybean Carrot
Seedling emergence, ER₅₀
as g ha⁻¹

Honeybees (Apis spp.)

Contact acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)

> 98.1

Apis mellifera

Moderate

Oral acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)

> 108

Apis mellifera

Low

Unknown mode acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)

Chronic

Notes

Bumblebees (Bombus spp.)

Contact acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)

Oral acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)

Mason bees (Osmia spp.)

Contact acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)

Oral acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)

Other bee species (1)

Acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg insect⁻¹)

Mode of exposure

Other bee species (2)

Acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg insect⁻¹)

Mode of exposure

Beneficial insects (Ladybirds)

Beneficial insects (Lacewings)

Beneficial insects (Parasitic wasps) as Mortality LR₅₀ g ha⁻¹

1462

Aphidius rhopalosiphi

Beneficial insects (Predatory mites) as Mortality LR₅₀ g ha⁻¹

> 1814

Typhlodromus pyri

Beneficial insects (Ground beetles)

Aquatic ecotoxicology

Property

Value

Source; quality score; and other information

Interpretation

Temperate Freshwater Fish - Acute 96 hour LC₅₀ (mg l⁻¹)

1.33

Cyprinodon variegatus marine species

Moderate

Temperate Freshwater Fish - Chronic 21 day NOEC (mg l⁻¹)

0.0115

Cyprinodon variegatus 28 day

Moderate

Tropical Freshwater Fish - Acute 96 hour LC₅₀ (mg l⁻¹)

Temperate Freshwater Aquatic invertebrates - Acute 48 hour EC₅₀ (mg l⁻¹)

2.21

Daphnia magna

Moderate

Temperate Freshwater Aquatic invertebrates - Chronic 21 day NOEC (mg l⁻¹)

0.144

Daphnia magna

Moderate

Tropical Freshwater Aquatic invertebrates - Acute 48 hour EC₅₀ (mg l⁻¹)

Aquatic crustaceans - Acute 96 hour LC₅₀ (mg l⁻¹)

> 1.30

Americamysis bahia

Moderate

Sediment dwelling organisms - Acute 96 hour LC₅₀ (mg l⁻¹)

Sediment dwelling organisms - Chronic 28 day NOEC, static, water (mg l⁻¹)

1.26

Chironomus riparius

Moderate

Sediment dwelling organisms - Chronic 28 day NOEC, sediment (mg kg⁻¹)

89.3

Chironomus riparius

Moderate

Aquatic plants (free-floating, growth) - Acute 7 day EC₅₀, biomass (mg l⁻¹)

2.13

Lemna gibba

Moderate

Aquatic plants (rooted, growth) - Acute 14 day EC₅₀, biomass (mg l⁻¹)

Algae - Acute 72 hour EC₅₀, growth (mg l⁻¹)

> 0.855

Pseudokirchneriella subcapitata

Moderate

Algae - Chronic 96 hour NOEC, growth (mg l⁻¹)

Mesocosm study data

NOEAEC mg l⁻¹

Marine bivalves

HUMAN HEALTH AND PROTECTION

General

Property

Value

Source; quality score; and other information

Interpretation

Threshold of Toxicological Concern (Cramer Class)

Low (class I)

Mammals - Acute oral LD₅₀ (mg kg⁻¹)

> 5000

Rat

Low

Mammals - Dermal LD₅₀ (mg kg⁻¹ body weight)

5000

Rat

Mammals - Inhalation LC₅₀ (mg l⁻¹)

Other Mammal toxicity endpoints

ADI - Acceptable Daily Intake (mg kg⁻¹ bw day⁻¹)

0.058

Rabbit SF=100

ARfD - Acute Reference Dose (mg kg⁻¹ bw day⁻¹)

0.058

Rabbit SF=100

AAOEL - Acute Acceptable Operator Exposure Level (mg kg⁻¹ bw day⁻¹)

AOEL - Acceptable Operator Exposure Level - Systemic (mg kg⁻¹ bw day⁻¹)

0.058

Rabbit SF=100

Dermal penetration studies (%)

1-4%

concentration dependent

Dangerous Substances Directive 76/464

Exposure Routes

Public

Acceptable for proposed uses

Occupational

Acceptable for proposed uses

MRLs

European

EU MRL pesticide database

Great Britain

GB MRL Register

Notes

Drinking Water Standards

Drinking Water MAC (μg l⁻¹)

Mammalian dose elimination route and rate

Health issues

Specific human health issues

Carcinogen

Genotoxic

Endocrine disruptor

; ; ; ;

No data found

Reproduction / development effects

Acetyl cholinesterase inhibitor

Neurotoxicant

Respiratory tract irritant

Skin irritant

Skin sensitiser

No data found

Eye irritant

Phototoxicant

No data found

General human health issues

Possible liver, kideny and bladder toxicant

Handling issues

Property

Value and interpretation

General

Not explosive or oxidising
Not expected to auto-ignite; Not highly flammable

CLP classification 2013

Environment: H400, H410, H411

WHO Classification

Not listed (Not listed)

UN Number

Waste disposal & packaging

Shelf-life, storage, stability and reactivity

TRANSLATIONS

Language

Name

English

halauxifen-methyl

French

halauxifene-metyl

German

Danish

Italian

Spanish

Greek

Polish

Swedish

halauxifen-metyl

Hungarian

Dutch

Norwegian

halauksifen-metyl

Record last updated:	25/05/2025
Contact:	aeru@herts.ac.uk
Please cite as:	Lewis, K.A., Tzilivakis, J., Warner, D. and Green, A. (2016) An international database for pesticide risk assessments and management. Human and Ecological Risk Assessment: An International Journal, 22(4), 1050-1064. DOI: 10.1080/10807039.2015.1133242