Citral

Citral	Last updated: 21/02/2026
(Also known as: geranialdehyde)

Hazard alerts

The following Pesticide Hazard Tricolour (PHT) 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. The alerts for Highly Hazardous Pesticides (HHPs) are based on applying the FAO/WHO (Type 1) and the PAN (Type II) criteria to PPDB data. Further details on the HHP indicators are given in the tables below. Neither the PHT nor the HHP hazard alerts take account of usage patterns or exposure, thus they do not represent risk.

PHT: Environmental fate	PHT: Ecotoxicity	PHT: Human health	Highly Hazardous Pesticide
Environmental fate Moderate alert: Drainflow: Moderately mobile Warning: Significant data are missing	Ecotoxicity Moderate alert: Fish acute ecotoxicity: Moderate Warning: Significant data are missing	Human health Moderate alert: Mammals acute toxicity: Moderate; Reproduction/development effects

GENERAL INFORMATION

Description

A plant-derived substance common in many essential oils and which demonstrates insecticidal, fungicide, antimicrobial and herbicidal activities

Example pests controlled

Spider mite (Tetranychus urticae); General insect eggs & larvae; Housedust mites; Postharvest fungal pathogens including moulds & rots; Blister blight fungus (Exobasidium vexans)

Example applications

Post-harvest food preparation; Citrus; Tea

Efficacy & activity

Appearance and life cycle

Taxonomic classification

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 pest management 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

Chemical structure

Isomerism

Citral exists as a mixture of two geometric isomers: geranial (trans-citral or E-isomer, approximately 60-70% in natural sources) and neral (cis-citral or Z-isomer, approximately 30-40%).

Chemical formula

C₁₀H₁₆O

Canonical SMILES

CC(=CCC/C(=C/C=O)/C)C

Isomeric SMILES

International Chemical Identifier key (InChIKey)

WTEVQBCEXWBHNA-JXMROGBWSA-N

International Chemical Identifier (InChI)

InChI=1S/C10H16O/c1-9(2)5-4-6-10(3)7-8-11/h5,7-8H,4,6H2,1-3H3/b10-7+

2D structure diagram/image available?

Yes

General status

Biopesticide type

Insecticide; Herbicide; Fungicide; Antimicrobal; Other substance

Other bioactivity & uses

Flavouring; Fragrance

Substance groups

Monoterpenoid aldehyde; Plant-derived substance

Minimum active substance purity

Known relevant impurities

Substance origin

Natural

Mode of action

Inhibits bacteria and fungi by disrupting cell membranes

Substance source

It occurs naturally in essential oils from plants such as lemongrass (up to 75%), verbena, lemon (2-5%), lime (6-9%), orange, litsea cubeba (70%), backhousia citriodora (85-97%), and others

Uses

Crop and harvest protection

Target pests

Spider mite (Tetranychus urticae); General insect eggs & larvae; Housedust mites; Postharvest fungal pathogens including moulds & rots; Blister blight fungus (Exobasidium vexans)

Target host

Post-harvest food preparation; Citrus; Tea

Farming system suitability

CAS RN

5392-40-5

EC number

205-476-5

CIPAC number

US EPA chemical code

PubChem CID

638011

Molecular mass

152.23

PIN (Preferred Identification Name)

(2E)-3,7-dimethylocta-2,6-dienal

IUPAC name

(2E)-3,7-dimethylocta-2,6-dienal

CAS name

3,7-dimethyl-2,6-octadienal

Global Governance status: 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

FEMA=2303

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)

Not applicable

Examples of recorded resistance

Physical state

A clear yellow coloured liquid with a lemon-like odour

Related substances & organisms

geranial

lemongrass oil

Commercial

Property

Value

Availability status

Current

Introduction & key dates

1948, first registration US

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

BASF

Example products using this active

Formulation and application details

Commercial production

Citral is commercially produced on a large scale through synthetic routes.The key intermediate is isoprenol (3-methyl-3-buten-1-ol), formed by addition of formaldehyde to isobutene. Isoprenol undergoes oxidative dehydrogenation (often over silver catalysts) to yield a mixture of prenal and related compounds, followed by isomerisation steps to prenol and prenal. These react under acidic catalysis to form an unsaturated acetal, which then undergoes thermal cleavage and rearrangement to produce citral as a roughly 1:1 mixture of geranial (E-isomer) and neral (Z-isomer). Historically and to a lesser extent today, natural citral is extracted by steam distillation or fractionation from essential oils of plants.

Impact on climate of production and use

ENVIRONMENTAL FATE

Property

Value

Source; quality score; and other information

Interpretation

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

1340

at 25 °C

High

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

Melting point (°C)

Boiling point (°C)

Degradation point (°C)

Flashpoint (°C)

(closed cup)

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

7.41 X 10⁰²

Calculated

Log P

2.87

Moderate

Fat solubility of residues

Solubility

Data type

Density (g ml⁻¹)

0.891

Dissociation constant pKa) at 25 °C

Vapour pressure at 20 °C (mPa)

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

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

Readily biodegradable

Soil degradation (days) (aerobic)

DT₅₀ (typical)

DT₅₀ (lab at 20 °C)

DT₅₀ (field)

DT₉₀ (lab at 20 °C)

DT₉₀ (field)

DT₅₀ modelling endpoint

Note

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

Note

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

Value

Note

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)

estimated

Moderately mobile

K_oc (mL g⁻¹)

Notes and range

Freundlich

K_f (mL g⁻¹)

K_foc (mL g⁻¹)

¹/_n

Notes and range

pH sensitivity

Known soil and groundwater metabolites

None

Other known metabolites

Metabolite name and reference

Aliases

Formation medium / Rate

Estimated maximum occurrence fraction

3-hydroxy-3,7-dimethyl-6-octenedioic acid

Mammal urinary

3,8-dihydroxy-3,7-dimethyl-6-octenolc acid

Mammal urinary

3,9-dihydroxy-3,7-dimethyl-6-octenolc acid

Mammal urinary

E/Z-3,7-dimethyl-2,6-octadienedioic acid

Mammal urinary

3,7-dimethyl-6-octenedioic acid

Mammal urinary

E-3,7-dimethyl-2,6-octadienoic acid

Mammal urinary

ECOTOXICOLOGY

Terrestrial ecotoxicology

Property

Value

Source; quality score; and other information

Interpretation

Mammals - Acute oral LD₅₀ (mg kg⁻¹)

> 1440

Mouse

Moderate

Mammals - Short Term Oral NOAEL (mg kg⁻¹ bw d⁻¹)

200

Rat NOAEL

Low

Mammals - Long Term (Chronic) Oral NOAEL (mg kg⁻¹ bw d⁻¹)

Birds - Acute LD₅₀ (mg kg⁻¹)

Birds - Short term dietary LC₅₀ (mg kg⁻¹ bw d⁻¹)

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

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

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

Soil micro-organisms

Collembola

Acute LC₅₀ (mg kg⁻¹)

Chronic NOEC (mg kg⁻¹)

Non-target plants

Vegetative vigour ER₅₀ (g ha⁻¹)

Seedling emergence ER₅₀ (g ha⁻¹)

Honeybees (Apis 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)

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)

Beneficial insects (Butterflies)

Contact

Notes

Oral

Notes

Aquatic ecotoxicology

Property

Value

Source; quality score; and other information

Interpretation

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

> 4.1

Oryzias latipes

Moderate

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

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

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

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, fonds growth, fresh) - 7 day (mg l⁻¹)

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

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

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

Mesocosm study data

NOEAEC mg l⁻¹

Marine bivalves

Regulatory Threshold Levels (RTLs)

Note: These RTLs have been calculated using the regulatory approach used in the European Union and based on ecotoxocity values in the PPDB.

Species group

RTL

Notes

Mammals

Worst case of acute and chronic mammals

Birds

No data

No data for acute and chronic birds

Soil organisms

No data

No data for acute and chronic earthworms

Terrestrial plants

No data

No data for non-target plants vegetative vigour and seedling emergence

Pollinators

No data

No data for contact and oral honeybees

Arthropods

No data

No data for parasitic wasps and predatory mites

Fish

0.041

Worst case of temperate acute and chronic fish

Aquatic invertebrates

No data

No data for temperate acute and chronic aquatic invertebrates

Aquatic plants

No data

No data for free-floating plants, rooted plants, acute and chronic algae

HUMAN HEALTH AND PROTECTION

General

Property

Value

Source; quality score; and other information

Interpretation

Threshold of Toxicological Concern (Cramer Class)

Mammals - Acute oral LD₅₀ (mg kg⁻¹)

> 1440

Mouse

Moderate

Mammals - Short Term Oral NOAEL (mg kg⁻¹ bw d⁻¹)

200

Rat NOAEL

Low

Mammals - Long Term (Chronic) Oral NOAEL (mg kg⁻¹ bw d⁻¹)

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

> 1000

Rabbit

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

Occupational

Mammalian dose elimination route and rate

Elimination is rapid and via urine as metabolites, with approximately 50% of the dose excreted within 24 hr

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

No data found

Eye irritant

Phototoxicant

No data found

General human health issues

May cause dermatitis
High doses may cause liver injury, body weight changes, upper respiratory irritation, eye damage, somnolence, and kidney effects.

Handling issues

Property

Value and interpretation

General

Incompatible with alkalies and strong acid
Auto-ignition temperature: 225 DegC
When heated to decomposition it emits acrid smoke and irritating fumes
Combustible - above 82 DegC explosive vapour/air mixtures may be formed

CLP classification 2013

Health: H315, H317

WHO Classification

UN Number

UN2810

Waste disposal & packaging

Shelf-life, storage, stability and reactivity

TRANSLATIONS

Language

Name

English

citral

French

German

Danish

Italian

Spanish

Greek

Polish

Swedish

Hungarian

Dutch

Norwegian

Record last updated:	21/02/2026
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

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