Fenbuconazole (Ref: RH 7592)

Fenbuconazole (Ref: RH 7592)	Last updated: 31/10/2024
(Also known as: fenethanil; RH 57592)

SUMMARY

Fenbuconazole is a triazole fungicide with systemic, protectant and curative actions. It has a low aqueous solubility but is soluble in many organic solvents. It is not volatile. It can be persistent in both soil and water systems depending upon local conditions. Based on its physico-chemical properties, fenbuconazole is not expected to leach to groundwater. It is moderately toxic to most aquatic species as well as earthworms and honeybees. Oral toxicity is low but there are a few concerns regarding chronic toxicity.

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 High alert: Potential for particle bound transport: High	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 contact ecotoxicity: Moderate; Bees acute oral ecotoxicity: Moderate; Earthworms acute ecotoxicity: Moderate; Earthworms chronic ecotoxicity: Moderate	Human health High alert: Mammals chronic toxicity: High; Endocrine disrupter

GENERAL INFORMATION

Description

A fungicide used to control a range of diseases including powdery mildew, black rot and scab

Example pests controlled

Powdery mildew, Black rot, Scab, Rusts, Smuts, Leaf spots

Example applications

Cereals; Vines; Top fruit; Stone fruit; Bananas; Pecans; Rice

Efficacy & activity

Availability status

Current

Introduction & key dates

1992, registered Europe

GB regulatory status

GB COPR regulatory status

Not approved

Date COPR inclusion expires

Withdrawn

GB LERAP status

None

EC Regulation 1107/2009 (repealing 91/414)

EC Regulation 1107/2009 status

Not approved

Dossier rapporteur/co-rapporteur

Sovenia/Austria

Date EC 1107/2009 inclusion expires

Expired

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, USA, Latin America, Asia, Africa

Chemical structure

Isomerism

A chiral molecule, fenbuconazole is a racemate of the R- and S-forms

Chemical formula

C₁₉H₁₇ClN₄

Canonical SMILES

C1=CC=C(C=C1)C(CCC2=CC=C(C=C2)Cl)(CN3C=NC=N3)C#N

Isomeric SMILES

No data

International Chemical Identifier key (InChIKey)

RQDJADAKIFFEKQ-UHFFFAOYSA-N

International Chemical Identifier (InChI)

InChI=1S/C19H17ClN4/c20-18-8-6-16(7-9-18)10-11-19(12-21,13-24-15-22-14-23-24)17-4-2-1-3-5-17/h1-9,14-15H,10-11,13H2

2D structure diagram/image available?

Yes

Cambridge Crystallographic Data Centre diagrams

Common Name	Relationship	Link
fenbuconazole	Unstated isomer

General status

Pesticide type

Fungicide

Substance groups

Triazole fungicide; Conazole fungicide

Minimum active substance purity

965 g kg⁻¹ (50:50 racemic mixture)

Known relevant impurities

EU dossier: none declared

Substance origin

Synthetic

Mode of action

Systemic, protectant and curative, acts by inhibiting sterol biosynthesis in fungi.

CAS RN

114369-43-6

EC number

406-140-2

CIPAC number

694

US EPA chemical code

129011

PubChem CID

86138

CLP index number

608-023-00-3

Molecular mass

336.82

PIN (Preferred Identification Name)

rac-(2R)-4-(4-chlorophenyl)-2-phenyl-2-(1H-1,2,4-triazol-1-ylmethyl)butanenitrile

IUPAC name

4-(4-chlorophenyl)-2-phenyl-2-(1H-1,2,4-triazol-1-ylmethyl)butyronitrile

CAS name

α-(2-(4-chlorophenyl)ethyl)-a-phenyl-1H-1,2,4-triazole-1-propanenitrile

Other status information

Relevant Environmental Water Quality Standards

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

Colourless to off-white crystalline powder

Formulations

Property

Value

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

Dow AgroSciences
Landseer
Agrovista

Example products using this active

Indar 5EW
Enable
Impala
Agrovista Radni

Formulation and application details

Often supplied as a oil emulsion which is mixed with water and applied as a spray

ENVIRONMENTAL FATE

Property

Value

Source; quality score; and other information

Interpretation

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

2.47

Low

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

132000

Ethyl acetate

250000

Acetone

680

n-Heptane

26000

Xylene

Melting point (°C)

126.5

Boiling point (°C)

Degradation point (°C)

360

exothermic decomposition above this temperature

Flashpoint (°C)

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

6.17 X 10⁰³

Calculated

Log P

3.79

High

Fat solubility of residues

Solubility

Insoluble

Data type

Regulatory data - metabolism and feeding studies show no residue accumlation

Density (g ml⁻¹)

1.28

Dissociation constant pKa) at 25 °C

Not applicable

No dissociation

Vapour pressure at 20 °C (mPa)

3.4 X 10^-04

Low volatility

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

3.01 X 10^-05

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 solution 195nm = 35600
Acidic solution 200nm = 20600
Basic solution 217nm = 12100

Surface tension (mN m⁻¹)

69.5

at 22°C

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)

152

Persistent

DT₅₀ (field)

Moderately persistent

DT₉₀ (lab at 20 °C)

659

Very persistent

DT₉₀ (field)

DT₅₀ modelling endpoint

Note

EU dossier lab studies DT₅₀ range 33-590 days, DT₉₀ range 109-1219 days, field studies DT₅₀ range 6-98 days ; Other studies DT₅₀ (1) lab data - no degradation after 363 days, field study range 28-84 days (B3), (2) 247 days (DW4)

Dissipation rate RL₅₀ (days) on plant matrix

Value

Note

Dissipation rate RL₅₀ (days) on and in plant matrix

Value

10.2

Note

Published literature RL₅₀ range 5.7-14.7 days, 2 field & undercover grown fruit, n=2

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 5 to pH 9

Water-sediment DT₅₀ (days)

3.4

Fast

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)

K_oc (mL g⁻¹)

Notes and range

Freundlich

K_f (mL g⁻¹)

Non-mobile

K_foc (mL g⁻¹)

4425

¹/_n

1.00

Notes and range

EU dossier: K_f range 5.1-115.4 mL g⁻¹, K_foc range 2185-9043 mL g⁻¹, ¹/_n range 0.845-1.222, Soils=5

pH sensitivity

Fate indices

Property

Value

Source; quality score; and other information

Interpretation

GUS leaching potential index

0.63

Calculated

Low leachability

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

Value

1.22 X 10^-02

Calculated

Note

Potential for particle bound transport index

High

Calculated

Potential for loss via drain flow

Non-mobile

Calculated

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

13.1

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)

160

Whole fish

Threshold for concern

CT₅₀ (days)

1.4

Known soil metabolites

Metabolite

Major/Minor fraction

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

Estimated maximum occurrence fraction

Notes

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

Major fraction

0.124

cis-5-(4-chlorophenyl)-dihydro-3-phenyl-3-(1H-1,2,4-triazole-1-ylmethyl)-2-3H-furanone (Ref: RH-9129)

Minor fraction

0.097

4-(4-chlorophenyl)-2-(methyl-1H-1,2,4-triazole)-4-oxo-2-phenylbutanenitrile (Ref: RH-6467)

Minor fraction

0.077

Known groundwater metabolites

None

Other known metabolites

Metabolite name and reference

Aliases

Formation medium / Rate

Estimated maximum occurrence fraction

1H-1,2,4-triazol-1-ylacetic acid (Ref: RH 4098)
Note: Toxicologically relevant

TAA; Triazole acetic acid

Rat

(2RS)-4-(4-chloro-3-hydroxyphenyl)-2-phenyl-2-(1H-1,2,4-triazol-1-ylmethyl)butanenitrile (Ref: RH 4911)
Note: Toxicologically relevant

hydroxy phenol fenbuconazole

Plant

(2RS)-4-(4-chlorophenyl)-2-(hydroxymethyl)-2-phenylbutanenitrile (Ref: RH 7968)

Animal

(2RS)-4-(4-chlorophenyl)-2-(4-hydroxyphenyl)-2-(1H-1,2,4-triazol-1-hydroxyphenyl)-2-(1H-1,2,4-triazol-1- (Ref: RH 1311)

4-phenol fenbuconazole

Animal

3-(1H-1,2,4-triazol-1-yl)-DL-alanine (Ref: RH 3968)
Note: Toxicologically relevant

triazole alanine

Plant

ECOTOXICOLOGY

Terrestrial ecotoxicology

Property

Value

Source; quality score; and other information

Interpretation

Mammals - Acute oral LD₅₀ (mg kg⁻¹)

> 2000

Rat

Low

Mammals - Short term dietary NOEL

(mg kg⁻¹)

> 1.4

Rat

High

(ppm diet)

> 20

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

Rat Reproductive NOAEL

High

Birds - Acute LD₅₀ (mg kg⁻¹)

> 2150

Colinus virginianus

Low

Birds - Short term dietary (LC₅₀/LD₅₀)

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

Anas platyrhynchos

Moderate

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

> 100

Eisenia foetida corr

Moderate

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

Eisenia foetida corr

Moderate

Soil micro-organisms

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

Dose: 1.49 mg kg⁻¹ 28 Day

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)

>= 5.5

Apis mellifera

Moderate

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

>= 5.2

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) as % Mortality at dose 0.136 kg ha⁻¹

2.8

Coccinella septempunctata Larva

Beneficial insects (Lacewings) as % Mortality at dose 0.066 kg ha⁻¹

14.1

Chrysoperla carnea

Beneficial insects (Parasitic wasps) as % Mortality at dose 0.136 kg ha⁻¹

Aphidius rhopalosiphi

Beneficial insects (Predatory mites) as % Mortality at dose 0.063 kg ha⁻¹

Typhlodromus pyri

Beneficial insects (Ground beetles) as % Mortality at dose 80 g ha⁻¹

Poecilus cupreus

Aquatic ecotoxicology

Property

Value

Source; quality score; and other information

Interpretation

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

1.5

Oncorhynchus mykiss

Moderate

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

0.32

Oncorhynchus mykiss

Moderate

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

> 4.52

Danio rerio Embryo

Moderate

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

2.3

Daphnia magna

Moderate

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

0.078

Daphnia magna

Moderate

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

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

0.75

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)

1.73

Chironomus riparius

Moderate

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

8.0

Chironomus riparius

Moderate

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

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

0.33

Pseudokirchneriella subcapitata

Moderate

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

0.18

Unknown species

Moderate

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)

> 2000

Rat

Low

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

5000

Rat

Mammals - Inhalation LC₅₀ (mg l⁻¹)

> 2.1

Rat 4 hr (nose only)

Other Mammal toxicity endpoints

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

0.006

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

0.3

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

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

0.02

Dermal penetration studies (%)

4-30

concentration dependent

Dangerous Substances Directive 76/464

Exposure Routes

Public

Vapour drift unlikley to be a concern to bystanders

Occupational

Acceptable risk for registered applications - PPE/PPC advised

MRLs

European

EU MRL pesticide database

Great Britain

GB MRL Register

Notes

Drinking Water Standards

Drinking Water MAC (μg l⁻¹)

0.1

EU Dir 89/778/EC limit; Calc MAC=18.0 µg l⁻¹

Mammalian dose elimination route and rate

Health issues

Specific human health issues

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

Possible liver & kidney toxicant
US EPA - possible human carcinogen
Endocrine issues - Inhibition of thyroid hormones production

Handling issues

Property

Value and interpretation

General

Not explosive or oxidising
IMDG Transport Hazard Class 9
Not explected to auto-ignite, Not highly flammable

CLP classification 2013

Environment: H400, H410

WHO Classification

III (Slightly hazardous)

UN Number

UN3077

Waste disposal & packaging

Packaging Group III (minor danger)

Shelf-life, storage, stability and reactivity

Chemically stable under standard ambient conditions

TRANSLATIONS

Language

Name

English

fenbuconazole

French

fenbuconazole

German

Fenbuconazol

Danish

fenbuconazol

Italian

fenbuconazolo

Spanish

fenbuconazol

Greek

Polish

fenbukonazol

Swedish

Hungarian

Dutch

Norwegian

Record last updated:	31/10/2024
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