Tebuconazole (Ref: HWG 1608)

Tebuconazole (Ref: HWG 1608)	Last updated: 15/03/2021
(Also known as: fenetrazole; terbuconazole; terbutrazole; ethyltrianol)

GENERAL INFORMATION

Description

A fungicide effective against various foliar diseases in cereals and other field crops

Example pests controlled

Smut; Bunt; Stripe rust; Yellow leaf spot; Powdery mildew; Scelerotinia rot; Black spot; Net blotch

Example applications

Cereals including wheat, barley, oat, rye; Grapes; Peanuts; Vegetables including onions, peas, pepper; Bananas; Sugarcane

Efficacy & activity

Wheat/Mildew=Low; Wheat/Septoria=Low; Wheat/Rust=High; Wheat/Ear blight=Moderate; Barley/Rhynchosporium=Low; Barley/Net blotch=Low; Barley/Ramularia=Low; Corn/Northern leaf blight=High; Corn/Rust=Low

Availability status

Current

Introduction & key dates

1986, first reported; 1988, first introduced South Africa

UK regulatory status

UK COPR regulatory status

Approved

Date COPR inclusion expires

31/08/2024

UK LERAP status

None (may vary with mixtures)

EC Regulation 1107/2009 (repealing 91/414)

EC Regulation 1107/2009 status

Approved

Dossier rapporteur/co-rapporteur

UK/Denmark

Date EC 1107/2009 inclusion expires

31/08/2021

EU Candidate for substitution (CfS)

Yes - two 'Persistent-Bioaccumulative-Toxic' criteria

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
✓	✓	✓	✓	✓	✓	✓	✓	✓

Also used in

Australia

Chemical structure

Isomerism

A chiral molecule. The technical material is an isomeric mixture of the (S-) and (R-) isomers. The R-form is more biologically active than the S-form.

Chemical formula

C₁₆H₂₂ClN₃O

Canonical SMILES

CC(C)(C)C(CCC1=CC=C(C=C1)Cl)(CN2C=NC=N2)O

Isomeric SMILES

No data

International Chemical Identifier key (InChIKey)

PXMNMQRDXWABCY-UHFFFAOYSA-N

International Chemical Identifier (InChI)

InChI=1S/C16H22ClN3O/c1-15(2,3)16(21,10-20-12-18-11-19-20)9-8-13-4-6-14(17)7-5-13/h4-7,11-12,21H,8-10H2,1-3H3

2D structure diagram/image available?

Yes

Cambridge Crystallographic Data Centre diagrams

Common Name	Relationship	Link
tebuconazole	Unstated isomer

General status

Pesticide type

Fungicide, Plant growth regulator

Substance group

Triazole

Minimum active substance purity

905 g kg⁻¹

Known relevant impurities

EU dossier - None declared

Substance origin

Synthetic

Mode of action

Systemic with protective, curative and eradicant action. Disrupts membrane function. Sterol biosynthesis inhibitor.

CAS RN

107534-96-3

EC number

403-640-2

CIPAC number

494

US EPA chemical code

128997

PubChem CID

86102

Molecular mass

307.82

PIN (Preferred Identification Name)

rac-(3R)-1-(4-chlorophenyl)-4,4-dimethyl-3-(1H-1,2,4-triazol-1-ylmethyl)pentan-3-ol

IUPAC name

(RS)-1-p-chlorophenyl-4,4-dimethyl-3-(1H-1,2,4-triazol-1-ylmethyl)pentan-3-ol

CAS name

α-(2-(4-chlorophenyl)ethyl)-α-(1,1-dimethylethyl)-1H-1,2,4-triazole-1-ethanol

Other status information

Relevant Environmental Water Quality Standards

Herbicide Resistance Classification (HRAC)

Not applicable

Herbicide Resistance Classification (WSSA)

Not applicable

Insecticide Resistance Classification (IRAC)

Not applicable

Fungicide Resistance Classification (FRAC)

Examples of recorded resistance

Physical state

Colourless crystals

Related substances & organisms

N,N-dimethyl capramide

clothianidin

triazoxide

prochloraz

prothioconazole

Formulations

Property

Value

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

Alpha Tebuconazole
Bezel
Cello
Coronet
Folicur
Grail
Kestrel
Mystique
Nativo
Riza
Sage
Silvacur
Raxil S

Example products using this active

AgriGuard
Bayer CropScience
Headland
Makhteshim-Agan
Nufarm
Syngenta

Formulation and application details

Often supplied as an oil in water emulsion or concentrate that is mixed with water and used as a spray

ENVIRONMENTAL FATE

Property

Value

Source; quality score; and other information

Interpretation

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

Low

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

200000

Dichloromethane

n-Hexane

57000

Toluene

96000

Octanol

Melting point (°C)

105

Boiling point (°C)

Decomposes before boiling

Degradation point (°C)

350

Flashpoint (°C)

Not expected to self ignite; Not highly flammable

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

5.01 X 10⁰³

Calculated

Log P

3.7

High

Bulk density (g ml⁻¹)

1.25

Dissociation constant pKa) at 25 °C

5.0

2013 Peer reviewed literature 5.0

Vapour pressure at 20 °C (mPa)

1.30 X 10^-03

Low volatility

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

1.00 X 10^-05

Non-volatile

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

Neutral solution: 221.4nm = 11980, 262.0nm = 304, 268.5nm = 408, 276.5nm = 368, 290.0nm <10

Surface tension (mN m⁻¹)

64.26

at 20°C 28.8mg l⁻¹

Degradation

Property

Value

Source; quality score; and other information

Interpretation

General biodegradability

Soil degradation (days) (aerobic)

DT₅₀ (typical)

Moderately persistent

DT₅₀ (lab at 20 °C)

365

Very persistent

DT₅₀ (field)

47.1

Moderately persistent

DT₉₀ (lab at 20 °C)

DT₉₀ (field)

177

DT₅₀ modelling endpoint

Note

EU dossier lab studies DT₅₀ >365 days, Field studies DT₅₀ range 25.8-91.6 days, DT₉₀ range 66-304 days; Other sources: DT₅₀ 610 days (DW4)

Dissipation rate RL₅₀ on plant matrix

Value

2.7

Note

Published literature RL₅₀ range 1.4-3.3 days, fruit from 2 field grown crops, n=2

Dissipation rate RL₅₀ on and in plant matrix

Value

16.1

Note

Published literature RL₅₀ range 1.0-59.4 days, 18 field & undercover grown crops, various matrices, n=24; Outlier - RL₅₀ peppers in cold storage = 106 days

Aqueous photolysis DT₅₀ (days) at pH 7

Value

Stable

Note

No significant photolytic degradation

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

Value

Stable

Note

Stable pH 5 to pH 9, at 25 °C, 28 days

Water-sediment DT₅₀ (days)

365

Stable

Water phase only DT₅₀ (days)

42.6

Stable

Soil adsorption and mobility

Property

Value

Source; quality score; and other information

Interpretation

Linear

K_d

K_oc

Notes and range

Freundlich

K_f

12.69

Slightly mobile

K_foc

769

¹/_n

0.84

Notes and range

EU dossier K_f range 7.67-15.86 mL g⁻¹, K_foc range 102-1249 mL g⁻¹, ¹/_n range 0.711-1.179; Other literature: Mean of 4 soils. Sandy loam - Sand 67% Silt 27% Clay 6% OC=1.4% pH=5.2 K_f=12.7; Silt - Sand 2% Silt 89% Clay 9% OC=1.8% pH=5.3 K_f=16.4; Sand - Sand 87.8% Silt 8.7% Clay 3.5% OC=0.75% pH=5.6 K_f=7.69; Sandy loam - Sand 58.6% Silt 28.1% Clay 13.2% OC=1.27% p

pH sensitivity

Fate indices

Property

Value

Source; quality score; and other information

Interpretation

GUS leaching potential index

1.86

Calculated

Transition state

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

Value

6.46 X 10^-02

Calculated

Note

Potential for particle bound transport index

Medium

Calculated

Potential for loss via drain flow

Slightly mobile

Calculated

Key metabolites

Metabolite

Formation medium

Estimated maximum occurrence fraction

1107/2009 relevancy

1,2,4-triazole (Ref: CGA 71019)

Soil

0.09

Minor fraction, Relevant

Other known metabolites

Metabolite name and reference

Aliases

Formation medium / Rate

Estimated maximum occurrence fraction

Metabolising enzymes

5-(4-chlorophenyl)-2,2-dimethyl-3-(1H-1,2,4-triazol-1-ylmethyl)pentane-1,3-diol

hydroxy-tebuconazole

Plant

2-chloro-5-[4-hydroxy-5,5-dimethyl-3-(1H-1,2,4-triazol-1-yl)hexyl]phenol

tebuconazole-m-hydroxy

Plant

(R,S)-2-amino-3-(1H-1,2,4-triazol-1-yl)propanoic acid, or 3-(1H-1,2,4-triazol-1-yl)-D,L-alanine

triazole alanine

Plant

2-hydroxy-3-(1H-1,2,4-triazol-1-yl)propanoic acid

triazole lactic acid

Plant

1H-1,2,4-triazol-1-ylacetic acid

triazole acetic acid

Plant

5-(4-chlorophenyl)-3-hydroxy-2,2-dimethyl-3-(1H-1,2,4-triazol-1-ylmethyl)pentanoic acid

tebuconazole-carboxylic acid

Animal

5-tert-butyl-5-(1H-1,2,4-triazol-1-ylmethyl)dihydrofuran-2(3H)-one

HWG 1608-lactone

Water (Photolysis); Water/sediment

4-hydroxy-5,5-dimethyl-4-(1H-1,2,4-triazol-1-ylmethyl)hexanoic acid

HWG 1608-pentanoic acid

Water (Photolysis); Water/sediment

sodium 5-(4-chlorophenyl)-3-hydroxy-2,2-dimethyl-3-(1H-1,2,4-triazol-1-ylmethyl)pentyl sulfate

hydroxy-tebuconazole-sulphate

Animal

ECOTOXICOLOGY

Property

Value

Source; quality score; and other information

Interpretation

Bio-concentration factor

BCF (l kg⁻¹)

Whole fish

Low potential

CT₅₀ (days)

Mammals - Acute oral LD₅₀ (mg kg⁻¹)

1700

Rat

Moderate

Mammals - Short term dietary NOEL

(mg kg⁻¹)

> 10.8

Rat

High

(ppm diet)

> 100

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

72.3

Unknown species Reproductive NOAEL

Moderate

Birds - Acute LD₅₀ (mg kg⁻¹)

1988

Colinus virginianus

Moderate

Birds - Short term dietary (LC₅₀/LD₅₀)

> 703 mg kg bw⁻¹ day⁻¹

Colinus virginianus

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

5.8

Colinus virginianus NOEL

High

Fish - Acute 96 hour LC₅₀ (mg l⁻¹)

4.4

Oncorhynchus mykiss

Moderate

Fish - Chronic 21 day NOEC (mg l⁻¹)

0.010

Oncorhynchus mykiss

Moderate

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

2.79

Daphnia magna

Moderate

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

0.01

Daphnia magna

Moderate

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

0.46

Mysidopsis bahia

Moderate

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

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

2.51

Chironomus riparius EC15

Moderate

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

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

0.144

Lemna gibba

Moderate

Non-target plants

> 750

Lepidium sativum
Seedling emergence, ER₅₀
as kg ha⁻¹

> 10.5

Lepidium sativum
Vegetative vigour, ER₅₀
as kg ha⁻¹

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

1.96

Scenedemus subspicatus

Moderate

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

0.1

Unknown species

Moderate

Honeybees (Apis spp.)

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

> 200

Apis mellifera

Low

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

> 83.05

Apis mellifera

Moderate

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

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 pollinators (1)

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

Mode of exposure

Other pollinators (2)

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

Mode of exposure

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

1381

Eisenia foetida

Low

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

Eisenia foetida 56 days

Moderate

Other soil macro-organisms

Acute LC₅₀ (mg kg⁻¹)

Chronic NOEC (mg kg⁻¹)

250

Folsomia candida

Other arthropod (1)

LR₅₀ g ha⁻¹

62.5

Mortality
Aphidius rhopalosiphi

% Effect

Other arthropod (2)

LR₅₀ g ha⁻¹

58.0

Mortality
Typhlodromus pyri

% Effect

Soil micro-organisms

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

Dose: 6.25 kg ha⁻¹

Mesocosm study data

NOEAEC mg l⁻¹

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)

1700

Rat

Moderate

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

2000

Rat

Mammals - Inhalation LC₅₀ (mg l⁻¹)

> 5.09

Rat 4 hr (nose only)

Other Mammal toxicity endpoints

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

0.03

Dog SF=100

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

0.03

Mouse SF=300

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

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

0.03

Dog SF=100

Dermal penetration studies (%)

Dangerous Substances Directive 76/464

Exposure Routes

Public

Acceptable risk for bystanders

Occupational

Operator and other worker exposure acceptable for proposed uses

MRLs

European

EU MRL pesticide database

Notes

Drinking Water Standards

Drinking Water MAC (μg l⁻¹)

0.1

EU Dir 89/778/EC limit

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

Targets liver/blood system
USEPA - possible human carcinogen

Handling issues

Property

Value and interpretation

General

Not explosive or oxidising
IMDG Transport Code is usually 9

CLP classification 2013

Health: H302, H361d
Environment: H411

EC Risk Classification

Reproduction risk category 3: R63
Xn - Harmful: R22
N - Dangerous for the environment: R51, R53

EC Safety Classification

S2, S22, S36/37, S61

WHO Classification

II (Moderately hazardous)

UN Number

Usually 3082

Waste disposal & packaging

Packaging Group III (minor danger)

TRANSLATIONS

Language

Name

English

tebuconazole

French

tebuconazole

German

Tebuconazol

Danish

tebuconazol

Italian

tebuconazolo

Spanish

tebuconazol

Greek

Polish

tebukonazol

Swedish

tebukonazol

Hungarian

tebukonazol

Dutch

tebuconazool

Record last updated:	15/03/2021
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