Mepiquat chloride (Ref: BAS 083W)

Mepiquat chloride (Ref: BAS 083W)	Last updated: 25/05/2025
(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: Drainflow: Slightly mobile	Ecotoxicity Moderate alert: Birds chronic ecotoxicity: Moderate; Daphnia acute ecotoxicity: Moderate; Earthworms acute ecotoxicity: Moderate; Earthworms chronic ecotoxicity: Moderate	Human health Moderate alert: Mammals acute toxicity: Moderate; Mammals chronic toxicity: Moderate; Reproduction/development effects; Neurotoxicant

GENERAL INFORMATION

Description

A plant growth regulator used to reduce vegetative growth and improve plant shape

Example pests controlled

Growth - reduces internodal elongation to improve plant shape and suppresses sprouts

Example applications

Cereals including wheat, oats, barley, rye, triticale; Cotton; Onions; Leeks; Garlic; Grass

Efficacy & activity

Efficacy demonsrated from extensive global use and field research

Availability status

Current

Introduction & key dates

1980, registered USA

GB regulatory status

GB COPR regulatory status

Approved

Date COPR inclusion expires

28/02/2029

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

Finland/Estonia

Date EC 1107/2009 inclusion expires

15/10/2025

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

Australia

Chemical structure

Isomerism

None

Chemical formula

C₇H₁₆ClN

Canonical SMILES

C[N+]1(CCCCC1)C.[Cl-]

Isomeric SMILES

International Chemical Identifier key (InChIKey)

VHOVSQVSAAQANU-UHFFFAOYSA-M

International Chemical Identifier (InChI)

InChI=1S/C7H16N.ClH/c1-8(2)6-4-3-5-7-8;/h3-7H2,1-2H3;1H/q+1;/p-1

2D structure diagram/image available?

Yes

General status

Pesticide type

Plant Growth Regulator

Substance groups

Quarternary ammonium PGR

Minimum active substance purity

575 g kg⁻¹

Known relevant impurities

EU 2024 dossier - N-methylpiperidine < 3 g kg⁻¹

Substance origin

Synthetic

Mode of action

Gibberellin biosynthesis inhibitor

CAS RN

24307-26-4

EC number

246-147-6

CIPAC number

440.302

US EPA chemical code

109101

PubChem CID

62781

CLP index number

613-127-00-7

Molecular mass

149.66

PIN (Preferred Identification Name)

IUPAC name

1,1-dimethylpiperidinium chloride

CAS name

1,1-dimethylpiperidinium chloride

Other status information

Relevant Environmental Water Quality Standards

Herbicide Resistance Class (HRAC MoA class)

None allocated

Herbicide Resistance Class (WSSA MoA class)

None allocated

Insecticide Resistance Class (IRAC MoA class)

Not applicable

Fungicide Resistance Class (FRAC MOA class)

Not applicable

Examples of recorded resistance

Physical state

White crystals when pure. Technical material is a pale yellow liquid.

Related substances & organisms

mepiquat

Formulations

Property

Value

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

BASF
King Tech Corp
Makhteshim Agan

Example products using this active

Stronghold
Terpal
Chamatkar
Pix

Formulation and application details

Often supplied as an aqueous solution

ENVIRONMENTAL FATE

Property

Value

Source; quality score; and other information

Interpretation

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

674000

High

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

312000

Methanol

Insoluble

Toluene

40.8

Acetone

Insoluble

n-Heptane

Melting point (°C)

Decomposes before melting

Boiling point (°C)

Decomposes before boiling

Degradation point (°C)

320

Flashpoint (°C)

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

2.69 X 10^-04

Calculated

Log P

-3.57

Low

Fat solubility of residues

Solubility

Insoluble

Data type

Regulatory data

Density (g ml⁻¹)

1.16

Dissociation constant pKa) at 25 °C

Not applicable

Completely dissociates in aqueous solution

Vapour pressure at 20 °C (mPa)

1.00 X 10^-05

Low volatility

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

2.99 X 10^-12

Non-volatile

Volatilisation as max % of applied dose lost

From plant surface

From soil surface

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

No significant absorption between 200-750nm at pH 1, 6 or 13

Surface tension (mN m⁻¹)

47.4

Degradation

Property

Value

Source; quality score; and other information

Interpretation

General biodegradability

Readily biodegradable

Soil degradation (days) (aerobic)

DT₅₀ (typical)

12.0

Non-persistent

DT₅₀ (lab at 20 °C)

12.0

Non-persistent

DT₅₀ (field)

DT₉₀ (lab at 20 °C)

85.1

Moderately persistent

DT₉₀ (field)

DT₅₀ modelling endpoint

Note

EU 2024 dossier lab studies DT₅₀ (normalisedl) range 4.58-33.08 days, DT₉₀ (actual) range 16.4-247.5 days, Soils=7

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 pH 3 to pH 9

Water-sediment DT₅₀ (days)

32.5

Moderately fast

Water phase only DT₅₀ (days)

7.5

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)

K_oc (mL g⁻¹)

Notes and range

Freundlich

K_f (mL g⁻¹)

8.57

Slightly mobile

K_foc (mL g⁻¹)

617

¹/_n

0.98

Notes and range

EU 2024 dossier: K_f range 1.63-24.5 mL g⁻¹, K_foc range 63-2238 mL g⁻¹, ¹/_n range 0.945-1.03, Soils=9

pH sensitivity

Fate indices

Property

Value

Source; quality score; and other information

Interpretation

GUS leaching potential index

1.31

Calculated

Low leachability

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

Value

2.14 X 10^-02

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

4.56

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)

Whole fish

Low potential

CT₅₀ (days)

Not available

Known soil and groundwater metabolites

None

Other known metabolites

Metabolite name and reference

Aliases

Formation medium / Rate

Estimated maximum occurrence fraction

4-hydroxymepiquat chloride

Rat; Animal

Agrobacterium radiobacter strain K84

Animal

methyl piperidine

Animal

ECOTOXICOLOGY

Terrestrial ecotoxicology

Property

Value

Source; quality score; and other information

Interpretation

Mammals - Acute oral LD₅₀ (mg kg⁻¹)

270

Rat

Moderate

Mammals - Short term dietary NOEL

(mg kg⁻¹)

Rat

(ppm diet)

3000

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

> 155

Rat Reproductive NOAEL

Moderate

Birds - Acute LD₅₀ (mg kg⁻¹)

> 2000

Colinus virginianus

Low

Birds - Short term dietary (LC₅₀/LD₅₀)

> 1326 mg kg bw⁻¹ day⁻¹

Colinus virginianus

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

> 100.7

Coturnix japonica NOAEL

Moderate

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

319.5

Eisenia foetida

Moderate

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

31.25

Eisenia foetida

Moderate

Soil micro-organisms

Nitrogen transformation: No significant adverse effect

Dose: 1.352 mg kg⁻¹ soi 84 daysl

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)

> 107.4

Apis mellifera

Low

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

> 165.0

Apis mellifera

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 LR₅₀ g ha⁻¹

> 1025

Chrysoperla carnea

Beneficial insects (Parasitic wasps) as Mortality LR₅₀ g ha⁻¹ 48 hr

> 1366

Aphidius rhopalosiphi

Beneficial insects (Predatory mites) as Mortality LR₅₀ L product BAS 098 00W/ha 7 day

> 3.36

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)

> 100

Oncorhynchus mykiss

Low

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

100

Oncorhynchus mykiss 28 day

Low

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

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

68.5

Daphnia magna

Moderate

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

12.5

Daphnia magna

Low

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

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

136.0

Americamysis bahia

Low

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)

2.6

Lemna gibba

Moderate

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

> 7.6

Myriophyllum spicatum

Moderate

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

> 1000

Pseudokirchneriella subcapitata

Low

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)

270

Rat

Moderate

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

1160

Rat

Mammals - Inhalation LC₅₀ (mg l⁻¹)

> 2.84

Rat

Other Mammal toxicity endpoints

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

0.065

Rat SF=200

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

0.3

Rat SF=100

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

0.23

Rat SF=100

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

0.23

Rat SF=100

Dermal penetration studies (%)

0.3-0.5

concentration dependent

Dangerous Substances Directive 76/464

Exposure Routes

Public

Minimal risk from dietary exposure
Risk assessment indicates ARfD would not normally be exceeded

Occupational

Risk of exposure acceptable under label recommendations for use for personal protection clothing and equipment

MRLs

European

EU MRL pesticide database

Great Britain

GB MRL Register

Notes

GB MRL amendment for mushrooms, April 2025. Consult register.

Drinking Water Standards

Drinking Water MAC (μg l⁻¹)

0.1

EU Dir 89/778/EC limit; Calc MAC=900 µg l⁻¹

Mammalian dose elimination route and rate

Rapid and extensive, within 48 hr of dosage mainly via urine

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

Moderately toxic
May effect hematological parameters
May impair neurological functions

Handling issues

Property

Value and interpretation

General

Prevent generation of mists
Not explosive or oxidising
Not expected to auto-ignite; Not highly flammable

CLP classification 2013

Health: H301, H332
Environment: H412

WHO Classification

II (Moderately hazardous)

UN Number

Waste disposal & packaging

Shelf-life, storage, stability and reactivity

TRANSLATIONS

Language

Name

English

mepiquat chloride

French

mepiquat-chlorure

German

Mepiquat chlorid

Danish

mepiquat-chlorid

Italian

mepiquat cloruro

Spanish

cloruro de mepicuat

Greek

Polish

chlorek mepikwatu

Swedish

mepikvatklorid

Hungarian

Dutch

Norwegian

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