Pyraclonil (Ref: NAI-1886)

Pyraclonil (Ref: NAI-1886)	Last updated: 26/05/2025
(Not known by any other names)

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; GUS: Transition state; Drainflow: Moderately mobile; Potential for particle bound transport: Medium	Ecotoxicity Moderate alert: Fish acute ecotoxicity: Moderate; Daphnia acute ecotoxicity: Moderate; Bees acute oral ecotoxicity: Moderate	Human health High alert: Carcinogen Warning: Significant data are missing

GENERAL INFORMATION

Description

A herbicide used for preemergence and early post emergence control of weeds in rice crops

Example pests controlled

Water hyacinth (Monochoria vaginalis); Chinese arrowhead (Sagittaria triflolia); Sedges; Barnyardgrass; Watergrass

Example applications

Paddy rice

Efficacy & activity

Availability status

Introduction & key dates

2007, first registered

GB regulatory status

GB COPR regulatory status

Not approved

Date COPR inclusion expires

Not applicable

GB LERAP status

No UK approval for use as a plant protection agent

EC Regulation 1107/2009 (repealing 91/414)

EC Regulation 1107/2009 status

Not approved

Dossier rapporteur/co-rapporteur

Not applicable

Date EC 1107/2009 inclusion expires

Not applicable

EU Candidate for substitution (CfS)

Not applicable

Listed in EU database

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

Japan; USA

Chemical structure

Isomerism

None

Chemical formula

C₁₅H₁₅ClN₆

Canonical SMILES

CN(CC#C)C1=C(C=NN1C2=NN3CCCCC3=C2Cl)C#N

Isomeric SMILES

International Chemical Identifier key (InChIKey)

IHHMUBRVTJMLQO-UHFFFAOYSA-N

International Chemical Identifier (InChI)

InChI=1S/C15H15ClN6/c1-3-7-20(2)15-11(9-17)10-18-22(15)14-13(16)12-6-4-5-8-21(12)19-14/h1,10H,4-8H2,2H3

2D structure diagram/image available?

Yes

General status

Pesticide type

Herbicide

Substance groups

Nitrile herbicide; Pyrazole herbicide

Minimum active substance purity

>98%

Known relevant impurities

Substance origin

Synthetic

Mode of action

Broad-spectrum. Inhibition of protoporphyrinogen oxidase (PPO) - cell membrane disruption

CAS RN

158353-15-2

EC number

805-557-0

CIPAC number

None allocated

US EPA chemical code

PubChem CID

11563984

CLP index number

No data found

Molecular mass

314.77

PIN (Preferred Identification Name)

1-(3-chloro-4,5,6,7-tetrahydropyrazolo[1,5-a]pyridin-2-yl)-5-[methyl(prop-2-yn-1-yl)amino]-1H-pyrazole-4-carbonitrile

IUPAC name

1-(3-chloro-4,5,6,7-tetrahydropyrazolo[1,5-a]pyridin-2-yl)-5-[methyl(prop-2-ynyl)amino]pyrazole-4-carbonitrile

CAS name

1-(3-chloro-4,5,6,7-tetrahydropyrazolo[1,5-a]pyridin-2-yl)-5-(methyl-2-propynylamino)-1H-pyrazole-4-carbonitrile

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

Formulations

Property

Value

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

Sumitomo Chemical Co.
Kyoyu Agri Co Ltd.
Nichino America
Inc

Example products using this active

Megazeta

Formulation and application details

Usually formulated as granules. Where approved, it may be applied aerially.

ENVIRONMENTAL FATE

Property

Value

Source; quality score; and other information

Interpretation

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

50.1

Moderate

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

Melting point (°C)

Boiling point (°C)

Degradation point (°C)

Flashpoint (°C)

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

1.51 X 10⁰²

Calculated

Log P

2.18

Low

Fat solubility of residues

Solubility

Data type

Density (g ml⁻¹)

1.34

Dissociation constant pKa) at 25 °C

Vapour pressure at 20 °C (mPa)

7.1 X 10^-03

Low volatility

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

1.2 X 10^-11

Non-volatile

Volatilisation as max % of applied dose lost

From plant surface

From soil surface

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

Surface tension (mN m⁻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)

Moderately persistent

DT₅₀ (field)

DT₉₀ (lab at 20 °C)

DT₉₀ (field)

DT₅₀ modelling endpoint

Note

US EPA data: Lab studies DT₅₀ values ranging from 8.4 – 76 days under aerobic conditions

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

104

Stable

Note

Corrected for summer sunlight at 35 N

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

Value

Stable

Note

Stable at pH 4, 7 and 9

Water-sediment DT₅₀ (days)

Water phase only DT₅₀ (days)

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)

7.6

Moderately mobile

K_oc (mL g⁻¹)

345

Notes and range

US EPA data K_f range 2.24-15.2 mL g⁻¹, K_oc range 163-733 mL g⁻¹, Soils =10

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

2.40

Calculated

Transition state

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

Value

1.33 X 10^-01

Calculated

Note

Potential for particle bound transport index

Medium

Calculated

Potential for loss via drain flow

Moderately mobile

Calculated

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

Bio-concentration factor

BCF (l kg⁻¹)

Low risk

Based on LogP < 3

Low risk

CT₅₀ (days)

Known soil metabolites

None

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)

1-(3-chloro-4,5,6,7-tetrahydropyrazolo[1,5-alpha]pyridin-2-yl)-5-(methylamino)-1H-pyrazole-4-carboxamide (Ref: pyraclonil M-6)

Unknown relevancy

1-(3-chloro-4,5,6,7-tetrahydropyrazolo[1,5-alpha]pyridin-2-yl)-5-(methyl(prop-2-enyl)amino)-1H-pyrazole-4-carbonitrile (Ref: pyraclonil M-11)

Unknown relevancy

1-(3-chloro-4,5,6,7-tetrahydropyrazolo[1,5-alpha]pyridin-2-yl)-5-(methyl(prop-2-yn-1-yl)amino)-1H-pyrazole-4-carboxamide (Ref: amidepyraclonil)

Unknown relevancy

Other known metabolites

Metabolite name and reference

Aliases

Formation medium / Rate

Estimated maximum occurrence fraction

1-(3-chloro-4,5,6,7-tetrahydropyrazolo[1,5-alpha]pyridin-2-yl)-5-(methylamino)-1H-pyrazole-4-carbonitrile
Note: US EPA data

pyraclonil M-1

Aqueous photolysis

>0.100

1-(3-chloro-4,5,6,7-tetrahydropyrazolo[1,5-alpha]pyridin-2-yl)-5-(methyl(prop-2-enyl)amino)-1H-pyrazole-4-carbonitrile
Note: US EPA data

pyraclonil M-11

Surface water

>0.100

1-(3-chloro-4,5,6,7-tetrahydropyrazolo[1,5-alpha]pyridin-2-yl)-5-(methylamino)-1H-pyrazole-4-carboxamide
Note: US EPA data

pyraclonil M-6

Surface water

>0.100

5-amino-1-(3-chloro-4,5,6,7-tetrahydropyrazolo[1,5-alpha]pyridin-2-yl)-1H-pyrazole-4-carboxamide
Note: US EPA data

pyraclonil M-7a

Surface water

<0.100

1-(3-chloro-4-hydroxy-4,5,6,7-tetrahydropyrazolo[1,5-alpha]pyridin-2-yl)-5-(methylamino)-1H-pyrazole-4-carbonitrile
Note: US EPA data

pyraclonil M-7b

Aqueous photolysis

<0.100

N-(1-(3-chloro-4,5,6,7-tetrahydropyrazolo[1,5-a]pyridin-2-yl)-4-cyano-1H-pyrazol-5-yl)-N-methylformamide
Note: US EPA data

pyraclonil methylformamide

Surface water

<0.100

5-amino-1-(3-chloro-4,5,6,7-tetrahydropyrazolo[1,5-alpha]pyridin-2-yl)-1H-pyrazole-4-carbonitrile
Note: US EPA data

Surface water

<0.100

11-(3-chloro-4-hydroxy-4,5,6,7-tetrahydropyrazolo[1,5-alpha]pyridin-2-yl)-5-(methyl(prop-2-yn-1-yl)amino)-1H-pyrazole-4-carbonitrile
Note: US EPA data

4-hydroxy-pyraclonil

Surface water

<0.100

4-(4'-chloro-4-cyano-5-(methylamino)-1'H-[1,3'-bipyrazol]-5'-yl)butanoic acid
Note: US EPA data

pyraclonil VIII

Surface water

<0.100

1-(3-chloro-4-hydroxy-4,5,6,7-tetrahydropyrazolo[1,5-alpha]pyridin-2-yl)-5-(methylamino)-1H-pyrazole-4-carbonitrile
Note: US EPA data

pyraclonil PM-5

Surface water

<0.100

ECOTOXICOLOGY

Terrestrial ecotoxicology

Property

Value

Source; quality score; and other information

Interpretation

Mammals - Acute oral LD₅₀ (mg kg⁻¹)

> 877

Mouse

Moderate

Mammals - Short term dietary NOEL

(mg kg⁻¹)

(ppm diet)

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

Birds - Acute LD₅₀ (mg kg⁻¹)

> 2160

Colinus virginianus

Low

Birds - Short term dietary (LC₅₀/LD₅₀)

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

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

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

Soil micro-organisms

Collembola

Acute LC₅₀ (mg kg⁻¹)

Chronic NOEC (mg kg⁻¹)

Non-target plants

Honeybees (Apis spp.)

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

> 100

Apis mellifera

Low

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

> 44.0

Apis mellifera

Moderate

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)

Beneficial insects (Predatory mites)

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)

6.0

Oncorhynchus mykiss

Moderate

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

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

23.05

Danio rerio

Moderate

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

15.09

Daphnia magna

Moderate

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

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)

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

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

0.0062

Lemna minor

High

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

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

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)

> 877

Mouse

Moderate

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

Mammals - Inhalation LC₅₀ (mg l⁻¹)

Other Mammal toxicity endpoints

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

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

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

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

Dermal penetration studies (%)

Dangerous Substances Directive 76/464

Exposure Routes

Public

Not expected to be hazardous to residents or bystanders when used as directed

Occupational

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

No data found

Respiratory tract irritant

Skin irritant

Skin sensitiser

No data found

Eye irritant

Phototoxicant

No data found

General human health issues

Possible liver and thyroid toxicant
EPA data: Likely to be Carcinogenic to Humans

Handling issues

Property

Value and interpretation

General

No information available

CLP classification 2013

Health: H302, H315, H319, H335
Environment: H400

WHO Classification

Not listed (Not listed)

UN Number

Waste disposal & packaging

Shelf-life, storage, stability and reactivity

TRANSLATIONS

Language

Name

English

pyraclonil

French

German

Danish

Italian

Spanish

Greek

Polish

Swedish

Hungarian

Dutch

Norwegian

Record last updated:	26/05/2025
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