Bixafen

Bixafen	Last updated: 20/05/2025
(Not known by any other names)

SUMMARY

Bixafen is a cereal fungicide used in the control of stem and leaf diseases. It has a low aqueous solubility and is not volatile. This substance can be very environmentally persistent but is not expected, based on its physico-chemical properties, to leach to groundwater. It is highly toxic to fish, moderately toxic to birds, aquatic invertebrates and algae but has a low toxicity to honeybees. Bixafen has a low mammalian toxicity via the oral route and is a probable reproduction/developmental toxin.

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 High alert: Persistent; Potential for particle bound transport: High	Ecotoxicity High alert: Fish acute ecotoxicity: High; Fish chronic ecotoxicity: High	Human health High alert: Reproduction/development effects

GENERAL INFORMATION

Description

A pyrazole fungicide for use in cereals for key stem and leaf disease control including strobilurin-resistant septoria.

Example pests controlled

Septoria leaf blotch; Ear blotch; Eyespot; Glume blotch; Fusarium ear blight; Sooty molds; Rusts

Example applications

Cereals including wheat, rye, triticale, barley, oats

Efficacy & activity

Availability status

Current

Introduction & key dates

2006, introduced

GB regulatory status

GB COPR regulatory status

Approved

Date COPR inclusion expires

31/05/2031

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

Czech Republic/Belgium

Date EC 1107/2009 inclusion expires

31/10/2027

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

Morocco

Chemical structure

Isomerism

None

Chemical formula

C₁₈H₁₂Cl₂F₃N₃O

Canonical SMILES

CN1C=C(C(=N1)C(F)F)C(=O)NC2=C(C=C(C=C2)F)C3=CC(=C(C=C3)Cl)Cl

Isomeric SMILES

No data

International Chemical Identifier key (InChIKey)

LDLMOOXUCMHBMZ-UHFFFAOYSA-N

International Chemical Identifier (InChI)

InChI=1S/C18H12Cl2F3N3O/c1-26-8-12(16(25-26)17(22)23)18(27)24-15-5-3-10(21)7-11(15)9-2-4-13(19)14(20)6-9/h2-8,17H,1H3,(H,24,27)/f/h24H

2D structure diagram/image available?

Yes

Cambridge Crystallographic Data Centre diagrams

Common Name	Relationship	Link
bixafen	-

General status

Pesticide type

Fungicide

Substance groups

Pyrazolium fungicide; Anilide fungicide; Pyrazolecarboximide fungicide

Minimum active substance purity

950 g/Kg

Known relevant impurities

EU dosssier - none declared

Substance origin

Synthetic

Mode of action

Succinate DeHydrogenase Inhibitor.

CAS RN

581809-46-3

EC number

642-423-9

CIPAC number

819

US EPA chemical code

128400

PubChem CID

11434448

CLP index number

No data found

Molecular mass

414.21

PIN (Preferred Identification Name)

N-(3',4'-dichloro-5-fluoro[1,1'-biphenyl]-2-yl)-3-(difluoromethyl)-1-methyl-1H-pyrazole-4-carboxamide

IUPAC name

N-(3',4'-dichloro-5-fluorobiphenyl-2-yl)-3-(difluoromethyl)-1-methylpyrazole-4-carboxamide

CAS name

N-(3',4'-dichloro-5-fluoro[1,1'-biphenyl]-2-yl)-3-(difluoromethyl)-1-methyl-1H-pyrazole-4-carboxamide

Other status information

Relevant Environmental Water Quality Standards

Herbicide Resistance Class (HRAC MoA class)

Not applicable

Herbicide Resistance Class (WSSA MoA class)

Not applicable

Insecticide Resistance Class (IRAC MoA class)

Not applicable

Fungicide Resistance Class (FRAC MOA class)

Examples of recorded resistance

Physical state

White powder

Formulations

Property

Value

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

Bayer CropScience

Example products using this active

Bixafen EC 125
Aviator
Xpro
Siltra

Formulation and application details

Usually supplied as an emulsifiable concentrate

ENVIRONMENTAL FATE

Property

Value

Source; quality score; and other information

Interpretation

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

0.49

Low

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

250000

Acetone

102000

Dichloromethane

32000

Methanol

16000

Toluene

Melting point (°C)

146.6

Boiling point (°C)

Decomposes before boiling

Degradation point (°C)

250

Flashpoint (°C)

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

2.00 X 10⁰³

Calculated

Log P

3.3

at 40 °C

High

Fat solubility of residues

Solubility

Soluble

Data type

Regulatory data - observed in metabolism and farm animal feeding studies

Density (g ml⁻¹)

Dissociation constant pKa) at 25 °C

Not applicable

No dissociation

Vapour pressure at 20 °C (mPa)

4.6 X 10^-05

Low volatility

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

3.89 X 10^-05

Non-volatile

Volatilisation as max % of applied dose lost

From plant surface

From soil surface

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

210nm=42825; 290nm=4000

Surface tension (mN m⁻¹)

70.7

Degradation

Property

Value

Source; quality score; and other information

Interpretation

General biodegradability

Soil degradation (days) (aerobic)

DT₅₀ (typical)

500

Very persistent

DT₅₀ (lab at 20 °C)

500

Very persistent

DT₅₀ (field)

254

Persistent

DT₉₀ (lab at 20 °C)

DT₉₀ (field)

>1000

DT₅₀ modelling endpoint

Note

EU dossier Lab studies DT₅₀ estimated >1 year; Field studies DT₅₀ range 30.6->1235 days, DT₉₀ estimated >1000 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

Stable

Note

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

Value

Stable

Note

Stable at pH 5, 7 & 9 at 50 °C

Water-sediment DT₅₀ (days)

Water phase only DT₅₀ (days)

Slow

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)

K_oc (mL g⁻¹)

Notes and range

Freundlich

K_f (mL g⁻¹)

62.5

Slightly mobile

K_foc (mL g⁻¹)

3869

¹/_n

0.877

Notes and range

EU dossier K_f range 40.5-102.7 mL g⁻¹; K_foc range 2920-4974 mL g⁻¹; ¹/_n range 0.857-0.855, Soils =5

pH sensitivity

Fate indices

Property

Value

Source; quality score; and other information

Interpretation

GUS leaching potential index

0.99

Calculated

Low leachability

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

Value

2.05 X 10^-02

Calculated

Note

Potential for particle bound transport index

High

Calculated

Potential for loss via drain flow

Slightly mobile

Calculated

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

10.4

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

Below the level of concern for long-range air transport

Bio-concentration factor

BCF (l kg⁻¹)

695

Whole fish

Threshold for concern

CT₅₀ (days)

1.33

Known soil metabolites

Metabolite

Major/Minor fraction

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

Estimated maximum occurrence fraction

Notes

3--(difluoromethyl)-1H-pyrazole-4-carboxylic acid

Minor fraction

0.029

CAS 151737-02-0; Bayer verified

Known groundwater metabolites

Metabolite

EC SANCO/221/2000 relevancy

ADI (mg kg⁻¹ bodyweight day⁻¹)

WHO drinking water guidance value (μg L⁻¹ day⁻¹)

3--(difluoromethyl)-1H-pyrazole-4-carboxylic acid

Not relevant

0.30

1800

Other known metabolites

Metabolite name and reference

Aliases

Formation medium / Rate

Estimated maximum occurrence fraction

N-{3',4'-dichloro-5-fluoro-x-[(6-Oulfo-β-D-glucopyranosyl)oxy]biphenyl-2-yl}-3-(difluoromethyl)-1-methyl-1H-pyrazole-4-carboxamide

Bixafen metabolite M20

Plant

1-O-[(3',4'-dichloro-5-fluorobiphenyl-2-yl){[3-(difluoromethyl)-1H-pyrazol-4-yl]carbonyl}amino]-D-glucopyranuronic acid

Bixafen metabolite M22

glucopyranuronic acid

Bixafen metabolite M44

Plant

3-(difluoromethyl)-1-methyl-1Hpyrazole-4-carboxamide

Bixafen metabolite M43

Rat (Urine); Plant

3-oxo-2,3-dihydro-1H-pyrazole-4-carboxylic acid

Bixafen metabolite M47

Plant

3-(difluoromethyl)-1-methyl-1Hpyrazole-4-carboxylic acid

Bixafen metabolite M42

Rat (Urine)

N-(3,4-dichloro-5-fluorobiphenyl-2-yl)-3-(difluoromethyl)-1H-pyrazole-4-carboxamide

Bifafen metabolite M21; BYF 00587-desmethyl; desmethyl bixafen

Plant; Animal; Rat

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)

169.2

Rat Reproductive NOAEL

Moderate

Birds - Acute LD₅₀ (mg kg⁻¹)

> 2000

Colinus virginianus

Low

Birds - Short term dietary (LC₅₀/LD₅₀)

> 1159 mg kg bw⁻¹ day⁻¹

Unknown species

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

24.5

Colinus virginianus

Moderate

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

> 1000

Eisenia foetida

Low

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

100

Eisenia foetida

Moderate

Soil micro-organisms

Collembola

Acute LC₅₀ (mg kg⁻¹)

Chronic NOEC (mg kg⁻¹)

7.74

Folsomia candida

Non-target plants

Honeybees (Apis spp.)

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

> 121.4

Apis mellifera

Low

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

> 100

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) as Mortality LR₅₀ g ha⁻¹

> 240

Chrysoperla carnea Larva

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

36.5

Aphidius rhopalosiphi

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

116

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)

0.095

Oncorhynchus mykiss

High

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

0.0046

Pimephales promelas 33 day

High

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

0.207

Danio rerio Embryo

Moderate

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

1.2

Daphnia magna

Moderate

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

0.05

Daphnia magna

Moderate

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

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

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

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

0.0156

Chironomus riparius

Moderate

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

20.0

Chironomus riparius

Moderate

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

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

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

0.097

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)

High (class III)

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)

> 5.38

Rat 4 hr (nose only)

Other Mammal toxicity endpoints

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

0.02

Rat SF=100

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

0.2

Rat SF=100

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

Not applicable

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

0.13

Rat SF=100

Dermal penetration studies (%)

0.76-4.1

concentration dependent

Dangerous Substances Directive 76/464

Exposure Routes

Public

Acceptable for intended uses

Occupational

Acceptable for intended uses

MRLs

European

EU MRL pesticide database

Great Britain

GB MRL Register

Notes

GB MRL levels for some commodities subject to change in late 2021

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

No data found

Respiratory tract irritant

Skin irritant

Skin sensitiser

No data found

Eye irritant

Phototoxicant

No data found

General human health issues

Possible thyroid and liver 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

WHO Classification

Not listed (Not listed)

UN Number

Waste disposal & packaging

Shelf-life, storage, stability and reactivity

TRANSLATIONS

Language

Name

English

bixafen

French

German

Danish

Italian

Spanish

Greek

Polish

Swedish

Hungarian

Dutch

Norwegian

biksafen

Record last updated:	20/05/2025
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