Prothioconazole (Ref: JAU 6476 )

Prothioconazole (Ref: JAU 6476 )	Last updated: 19/10/2025
(Also known as: AMS 21619)

SUMMARY

Hazard 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. These hazard alerts do not take account of usage patterns or exposure, thus do not represent risk.

Environmental fate	Ecotoxicity	Human health
Environmental fate Moderate alert: Drainflow: Slightly mobile	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 oral ecotoxicity: Moderate	Human health Moderate alert: Mammals chronic toxicity: Moderate; Genotoxic; Reproduction/development effects

GENERAL INFORMATION

Description

A fungicide for use both as a seed treatment and foliar spray to treat a variety of leaf and stem diseases

Example pests controlled

Phoma leaf spot; Phoma stem canker; Powdery mildew; Yellow rust; Brown rust; Tan spot; Septoria leaf and glume blotch

Example applications

Cereals including barley, rye, wheat, oats, spelt, triticale

Efficacy & activity

Wheat/Eyespot=High; Wheat/Mildew=Moderate; Wheat/Septoria=Moderate; Wheat/Yellow rust=High; Wheat/Brown rust=Low; Wheat/Ear blight=Moderate; Barley/Rhynchosporium=Moderate; Barley/Mildew=Moderate; Barley/Rust=Low; Barley/Net blotch=Moderate; Barley/Ramularia=Moderate; Corn/Northern leafblight=Moderate; Corn/Rust=Moderate; Corn/Eyespot=High; Soybean/Rust=High; Soybean/White mould=Moderate

GB regulatory status

GB COPR regulatory status

Approved

Date COPR inclusion expires

32/07/2029

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

Poland/France

Date EC 1107/2009 inclusion expires

31/03/2027

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

Prothioconazole exhibits stereoisomerism due to the presence of a chiral centre in its molecular structure. Specifically, it contains a tetrahedral carbon atom bonded to four different substituents, giving rise to two enantiomers. The technical material is a racemate comprising equal amounts of (R)- and (S)-prothioconazole.

Chemical formula

C₁₄H₁₅Cl₂N₃OS

Canonical SMILES

C1CC1(C(CC2=CC=CC=C2Cl)(CN3C(=S)N=CN3)O)Cl

Isomeric SMILES

International Chemical Identifier key (InChIKey)

MNHVNIJQQRJYDH-UHFFFAOYSA-N

International Chemical Identifier (InChI)

InChI=1S/C14H15Cl2N3OS/c15-11-4-2-1-3-10(11)7-14(20,13(16)5-6-13)8-19-12(21)17-9-18-19/h1-4,9,20H,5-8H2,(H,17,18,21)

2D structure diagram/image available?

Yes

Cambridge Crystallographic Data Centre diagrams

Common Name	Relationship	Link
prothioconazole	Unstated isomer
prothioconazole	-

General status

Pesticide type

Fungicide

Substance groups

Conazole fungicide

Minimum active substance purity

970 g kg⁻¹

Known relevant impurities

EU dossier - Toluene 5g kg⁻¹; other substances, including prothioconazole-desthio & triazole-1-ethanol, at undefined levels

Substance origin

Synthetic

Mode of action

Systemic with protective, curative and eradicative action. Long lasting activity. Sterol biosynthesis inhibitor.

CAS RN

178928-70-6

EC number

605-841-2

CIPAC number

745

US EPA chemical code

1133961

PubChem CID

6451142

Molecular mass

344.26

PIN (Preferred Identification Name)

IUPAC name

(RS)-2-[2-(1-chlorocyclopropyl)-3-(2-chlorophenyl)-2-hydroxypropyl]-2,4-dihydro-1,2,4-triazole-3-thione

CAS name

2-[2-(1-chlorocyclopropyl)-3-(2-chlorophenyl)-2-hydroxypropyl]-1,2-dihydro-3H-1,2,4-triazole-3-thione

Listed (✓) under

UK Poisons List Order 1972	Rotterdam Convention	Montreal Protocol
XNo The Poisons List Order 1972	XNo Rotterdam Convention	XNo Montreal Protocol
Stockholm Convention	OSPAR	EU Water Framework Directive
XNo Stockholm Convention	XNo OSPAR	XNo EU Water Framework Directive

Relevant Environmental Water Quality Standards

Forever chemical

Highly Hazardous Pesticide (HHP)

Type I

Type II

Other status information

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 to beige crystalline powder depending on purity

Commercial

Property

Value

Availability status

Current

Introduction & key dates

Circa 2002, introduced

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

AgriGuard
Bayer CropScience
Clayton
Makhteshim
Standon

Example products using this active

Cello
Fandango
Helix
Jaunt
Kestrel
Proline
Rivet
Aviator
Ascra Xpro

Formulation and application details

Often supplied as an emuslifiable concentrate that is used as an aqueous foliar spray

Commercial production

The production of prothioconazole involves a six-step chemical synthesis that begins with a chlorination cyclisation reaction to form a key intermediate, followed by a Claisen condensation with another compound. This intermediate then undergoes epoxidation, which is subsequently reacted with hydrazine hydrate to form a hydrazine derivative. The next step involves reacting this compound with formaldehyde and thiocyanate to produce a triazole-thione precursor. Finally, oxidation of this precursor yields prothioconazole.

Impact on climate of production and use

Precise life cycle emissions are unpublished but Audsley et al. (2009) reported that it takes 475 MJ of energy per kg produced. This is equivalent to approximately 32.8 kg CO₂e. There will also be emissions associated with packaging, transport and application.

ENVIRONMENTAL FATE

Property

Value

Source; quality score; and other information

Interpretation

Solubility - In water at 20 °C at pH 7 (mg l⁻¹)

22.5

Moderate

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

215000

Ethyl acetate

280000

Acetone

n-Heptane

8000

Xylene

Melting point (°C)

140.3

Boiling point (°C)

No boiling point under normal conditions

Degradation point (°C)

220

Exothermic effect

Flashpoint (°C)

403

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

1.00 X 10⁰²

Calculated

Log P

2.0

Low

Fat solubility of residues

Solubility

Soluble

Data type

Regulatory data - observed in metabolism and farm animal feeding studies

Density (g ml⁻¹)

1.36

Dissociation constant pKa) at 25 °C

6.9

Weak acid

Vapour pressure at 20 °C (mPa)

7.4 X 10^-07

Low volatility

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

1.1 X 10^-08

Non-volatile

Volatilisation as max % of applied dose lost

From plant surface

Negligible

24 hr

From soil surface

Negligible

24 hr

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

Neutral: 202nm=26235, 216nm=13521, 255nm=11850
pH2: 202nm=28193, 216nm=13561, 255nm=12568
pH10: 219nm=14261, 248nm=8972

Surface tension (mN m⁻¹)

67.4

at 20 °C 99.8 %

Degradation

Property

Value

Source; quality score; and other information

Interpretation

General biodegradability

Not readily biodegradable

Soil degradation (days) (aerobic)

DT₅₀ (typical)

14.1

Non-persistent

DT₅₀ (lab at 20 °C)

0.27

Non-persistent

DT₅₀ (field)

0.77

Non-persistent

DT₉₀ (lab at 20 °C)

7.49

Non-persistent

DT₉₀ (field)

4.71

DT₅₀ modelling endpoint

1.1

worse case lab value

Note

EU 2025 dossier lab studies DT₅₀ (measured) range 0.017-1.1 days, DT₉₀ (measured) range 0.246-46.9 days, Soils = 8; 2018 dossier field studies DT₅₀ range 0.49-1.4 days, DT₉₀ range 3.9-5.9 days, Soils=8

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

2.1

Moderately fast

Note

Data for sterile solution pH7 simulated sunlight equivalent to DT₅₀ ~9 days solar summer conditions

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

Value

Stable

Note

Stable pH 4 to pH 9 at 25 and 50 °C

Water-sediment DT₅₀ (days)

0.82

Fast

Water phase only DT₅₀ (days)

0.37

Fast

Sediment phase only DT₅₀ (days)

24.9

Slow

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)

15.2

Slightly mobile

K_oc (mL g⁻¹)

1765

Notes and range

Prothioconazole is unstable - data unreliable

Freundlich

K_f (mL g⁻¹)

K_foc (mL g⁻¹)

¹/_n

Notes and range

pH sensitivity

Fate indices

Property

Value

Source; quality score; and other information

Interpretation

GUS leaching potential index

-0.09

Calculated

Low leachability

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

Value

8.77 X 10^-05

Calculated

Note

Potential for particle bound transport index

Low

Calculated

Potential for loss via drain flow

Slightly mobile

Calculated

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

1.1

Calculated using the Atkinson method. Assumed 1.5E+06 OH/cm³, 12 hr. EU trigger for long-range transport is DT₅₀ in air <2 days.

Below the level of concern for long-range air transport

Bio-concentration factor

BCF (l kg⁻¹)

18.8

Low potential

CT₅₀ (days)

0.6

Known soil metabolites

Metabolite

Major/Minor fraction

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

Estimated maximum occurrence fraction

Notes

2-(1-chlorocyclopropyl)-1-(2-chlorophenyl)-3-(4,5-dihydro-5-methylthio-1,2,4-triazolyl-1)-propan-2-ol

Major fraction

0.235

alpha-(1-chlorocyclopropyl)-alpha-o(2-chlorophenyl)methyl-1H-1,2,4-triazole-1-ethanol

Major fraction

0.337

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)

2-(1-chlorocyclopropyl)-1-(2-chlorophenyl)-3-(4,5-dihydro-5-methylthio-1,2,4-triazolyl-1)-propan-2-ol

Not relevant

0.01

alpha-(1-chlorocyclopropyl)-alpha-o(2-chlorophenyl)methyl-1H-1,2,4-triazole-1-ethanol

Relevant

Other known metabolites

None

ECOTOXICOLOGY

Terrestrial ecotoxicology

Property

Value

Source; quality score; and other information

Interpretation

Mammals - Acute oral LD₅₀ (mg kg⁻¹)

> 6200

Rat

Low

Mammals - Short term dietary NOEL

(mg kg⁻¹)

> 25

Dog

High

(ppm diet)

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

95.6

Rat Reproductive NOAEL

Moderate

Birds - Acute LD₅₀ (mg kg⁻¹)

> 2000

Colinus virginianus

Low

Birds - Short term dietary (LC₅₀/LD₅₀)

> 5000 mg kg feed⁻¹

Anas platyrhynchos

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

Anas platyrhynchos NOEL

Moderate

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

> 1000

Eisenia foetida

Low

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

>= 128.7

Eisenia foetida corr

Low

Soil micro-organisms

Nitrogen transformation: No significant adverse effect

Dose: 0.0392 mg kg⁻¹ soil 28 Day

Collembola

Acute LC₅₀ (mg kg⁻¹)

Chronic NOEC (mg kg⁻¹)

>= 32.0

Folsomia candida corr

Non-target plants

Vegetative vigour ER₅₀ (g ha⁻¹)

> 0.28

10 plant species tested

Seedling emergence ER₅₀ (g ha⁻¹)

> 0.28

10 plant species tested

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)

> 71

Apis mellifera

Moderate

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

Chronic as 10-day LDD₅₀ µg bee⁻¹ day⁻¹

> 3.8

Apis mellifera

Notes

Bumblebees (Bombus spp.)

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

> 100

Bombus terrestris

Low

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

> 214

Bombus terrestris

Low

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) as Mortality LR₅₀ 15 day kg ha⁻¹, Std lab test

0.76

Coccinella septempunctata Lava

Moderate

Beneficial insects (Lacewings) as Mortality LR₅₀ 19 day kg ha⁻¹, Std lab test

> 0.84

Chrysoperla carnea Larva

Moderate

Beneficial insects (Parasitic wasps) as Mortality LR₅₀ kg ha⁻¹, Std lab test

0.022

Aphidius rhopalosiphi

High

Beneficial insects (Predatory mites) as Mortality LR₅₀ kg ha⁻¹, Std lab test

> 0.09

Typhlodromus pyri

High

Beneficial insects (Ground beetles) as Mortality ER₅₀ 14 day, Extended lab test

> 0.022

Poecillus cupreus

Aquatic ecotoxicology

Property

Value

Source; quality score; and other information

Interpretation

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

1.83

Oncorhynchus mykiss

Moderate

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

0.308

Oncorhynchus mykiss

Moderate

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

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

1.3

Daphnia magna

Moderate

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

0.56

Daphnia magna

Moderate

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

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

> 2.4

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)

9.14

Chironomus riparius

Moderate

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

Aquatic Plants (free-floating, fonds growth, fresh) - 7 day (mg l⁻¹) (ErC₅₀, Semi-static)

> 0.1142

Lemna gibba

Moderate

Aquatic plants (rooted, growth rate, fresh) - 14 day (mg l⁻¹)

Algae - Acute (growth rate, fresh; mg l⁻¹) (96 hr ErC₅₀, Static)

2.18

Raphidocelis subcapitata

Moderate

Algae - Chronic (growth rate, fresh; mg l⁻¹)

Mesocosm study data

NOEAEC mg l⁻¹

Marine bivalves – EC₅₀ 96 hr shell deposition (mg l⁻¹)

2.9

Crassostrea virginica

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)

> 6200

Rat

Low

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

> 2000

Rat

Mammals - Inhalation LC₅₀ (mg l⁻¹)

> 4.99

Rat

Other Mammal toxicity endpoints

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

0.036

Dog 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)

0.2

Rat SF=100

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

0.036

Dog SF=100

Dermal penetration studies (%)

6-70

concentration dependent

Dangerous Substances Directive 76/464

Exposure Routes

Public

No unacceptable risks to bystanders identified

Occupational

No unacceptable risks to operators or other workers identified for intended uses

MRLs

European

EU MRL pesticide database

Great Britain

GB MRL Register

Notes

GB MRL modified for oats Jan 2024 - see UK HSE website

Drinking Water Standards

Drinking Water MAC (μg l⁻¹)

0.1

EU Dir 89/778/EC limit

Mammalian dose elimination route and rate

Extensive metabolism with rapid 90% via biliary excretion, 2% urinary

Health issues

Specific human health issues (hazard-based)

Carcinogen

Genotoxic

Endocrine disruptor

; ; ; ;

Reproduction / development effects

Acetyl cholinesterase inhibitor

Neurotoxicant

Respiratory tract irritant

Skin irritant

Skin sensitiser

Eye irritant

Phototoxicant

General human health issues

Possible liver & kidney toxicant

Handling issues

Property

Value and interpretation

General

Not explosive or oxidising
IMDG Transport Hazard Class 9
Not highly flammable; Not expected to auto-ignite

CLP classification 2013

Environment: H400, H410, H411

WHO Classification

U (Unlikely to present an acute hazard)

UN Number

UN3077

Waste disposal & packaging

Packaging Group III (minor danger)

Shelf-life, storage, stability and reactivity

Chemically stable at standard ambient conditions

TRANSLATIONS

Language

Name

English

prothioconazole

French

prothioconazole

German

Prothioconazole

Danish

prothioconazol

Italian

protioconazolo

Spanish

protioconazol

Greek

Polish

protiokonazol

Swedish

protiokonazol

Hungarian

Dutch

prothioconazool

Norwegian

protiokonazol

Record last updated:	19/10/2025
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