Acibenzolar-S-methyl (Ref: CGA245704)

Acibenzolar-S-methyl (Ref: CGA245704)	Last updated: 12/01/2021
(Also known as: benzothiadiazole; 1,2,3-benzothiadiazole-7-carbothioic acid; azibenzolar-S-methyl; ASM)

SUMMARY

Acibenzolar-S-methyl is a preventative fungicide that is currently approved for EU use. It is not highly soluble in water but is highly soluble in most organic solvents. It is quite volatile. It is not expected to leach to groundwater. It is slightly mobile but tends not to be persistence in soil or aquatic systems. It has a moderate mammalian toxicity and there is some concern regarding its potential for bioaccumulation. Acibenzolar-S-methyl is moderately toxic to birds, honeybees, earthworms and most aquatic organisms.

GENERAL INFORMATION

Description

A preventative fungicide used to control various fungi, bacteria and viruses but also has some insecticide activity

Example pests controlled

Downy mildew; White rust; Bacteria spot; Bacteria speck; Blue mould

Example applications

Leafy vegetables; Tobacco; Tomatoes; Cotton

Efficacy & activity

Availability status

Current

Introduction & key dates

1996, Germany

UK regulatory status

UK COPR regulatory status

Not approved

Date COPR inclusion expires

Not applicable

UK LERAP status

Not applicable

EC Regulation 1107/2009 (repealing 91/414)

EC Regulation 1107/2009 status

Approved

Dossier rapporteur/co-rapporteur

France/Spain

Date EC 1107/2009 inclusion expires

31/03/2031

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
		✓		✓

Also used in

Australia; USA

Chemical structure

Isomerism

Isomeric

Chemical formula

C₈H₆N₂OS₂

Canonical SMILES

CSC(=O)C1=C2C(=CC=C1)N=NS2

Isomeric SMILES

No data

International Chemical Identifier key (InChIKey)

UELITFHSCLAHKR-UHFFFAOYSA-N

International Chemical Identifier (InChI)

InChI=1S/C8H6N2OS2/c1-12-8(11)5-3-2-4-6-7(5)13-10-9-6/h2-4H,1H3

2D structure diagram/image available?

Yes

General status

Pesticide type

Fungicide, Insecticide, Plant activator

Substance group

Benzothiadiazole

Minimum active substance purity

970 g kg⁻¹

Known relevant impurities

EU dossier - Toluene < 5g kg⁻¹

Substance origin

Synthetic

Mode of action

Systemic Activated Resistance (SAR). Induces host plant defence.

CAS RN

135158-54-2

EC number

420-050-0

CIPAC number

597

US EPA chemical code

061402

PubChem CID

86412

Molecular mass

210.3

PIN (Preferred Identification Name)

S-methyl 1,2,3-benzothiadiazole-7-carbothioate

IUPAC name

S-methyl benzo[1,2,3]thiadiazole-7-carbothioate

CAS name

1,2,3-benzothiadiazole-7-carbothioic acid, S-methyl ester

Other status information

Relevant Environmental Water Quality Standards

Herbicide Resistance Classification (HRAC)

Not applicable

Herbicide Resistance Classification (WSSA)

Not applicable

Insecticide Resistance Classification (IRAC)

Not known

Fungicide Resistance Classification (FRAC)

Examples of recorded resistance

Physical state

White to beige crystalline powder

Formulations

Property

Value

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

Actigard
Bion 50WG
Blockade
Boost

Example products using this active

Novartis
Syngenta

Formulation and application details

Usually supplied as water dispersible granules for foliar application or as a seed treatment.

ENVIRONMENTAL FATE

Property

Value

Source; quality score; and other information

Interpretation

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

7.7

Low

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

28000

Acetone

36000

Toluene

1300

Hexane

4200

Methanol

Melting point (°C)

133

Boiling point (°C)

267

Degradation point (°C)

Flashpoint (°C)

Not expected to self ignite; Not highly flammable

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

1.26 X 10⁰³

Calculated

Log P

3.1

at 25 °C

High

Bulk density (g ml⁻¹)

1.54

Dissociation constant pKa) at 25 °C

Not applicable

No dissociation

Vapour pressure at 20 °C (mPa)

0.46

Low volatility

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

1.30 X 10^-02

Non-volatile

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

253nm = 14700, 288nm = 5400, 324nm = 7200

Surface tension (mN m⁻¹)

70.7

at 20.5 °C

Degradation

Property

Value

Source; quality score; and other information

Interpretation

General biodegradability

Soil degradation (days) (aerobic)

DT₅₀ (typical)

0.138

Non-persistent

DT₅₀ (lab at 20 °C)

0.131

Non-persistent

DT₅₀ (field)

17.1

Non-persistent

DT₉₀ (lab at 20 °C)

0.986

Non-persistent

DT₉₀ (field)

DT₅₀ modelling endpoint

Note

EU dossier Lab studies DT₅₀ range 0.031-0.441 days, DT₉₀ range 0.36-3.3 days; Field studies DT₅₀ range 0.1-30 days; Other sources: 16.0 days (DW3)

Dissipation rate RL₅₀ on plant matrix

Value

Note

Dissipation rate RL₅₀ on and in plant matrix

Value

Note

Aqueous photolysis DT₅₀ (days) at pH 7

Value

0.1

Fast

Note

DT₅₀: 0.75 hrs at pH 5, 25 °C

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

Value

162

Persistent

Note

pH sensitive: 1400 days at pH 5, <1 day at pH 9

Water-sediment DT₅₀ (days)

Fast

Water phase only DT₅₀ (days)

Moderately fast

Soil adsorption and mobility

Property

Value

Source; quality score; and other information

Interpretation

Linear

K_d

K_oc

Notes and range

Freundlich

K_f

19.0

Slightly mobile

K_foc

1650

¹/_n

0.83

Notes and range

EU dossier K_f range 3.6-58.0 mL g⁻¹, K_foc range 493-3288 mL g⁻¹, ¹/_n range 0.75-1.00, Soils=10

pH sensitivity

Fate indices

Property

Value

Source; quality score; and other information

Interpretation

GUS leaching potential index

0.96

Calculated

Low leachability

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

Value

1.68 X 10^-02

Calculated

Note

Potential for particle bound transport index

Low

Calculated

Potential for loss via drain flow

Slightly mobile

Calculated

Key metabolites

Metabolite

Formation medium

Estimated maximum occurrence fraction

1107/2009 relevancy

benzo(1,2,3)thiadiazole-7-carboxylic acid (Ref: CGA 210007)

Soil

0.961

Major fraction, Relevant

6-hydroxy-benzo(1,2,3)thiadiazole-7-carboxylic acid (Ref: SYN 546642)

Soil

0.390

Major fraction, Relevant

Other known metabolites

Metabolite name and reference

Aliases

Formation medium / Rate

Estimated maximum occurrence fraction

Metabolising enzymes

4-hydroxy acibenzolar (Ref: CGA 324041)
Note: Not toxicologically relevant

Plant

5-hydroxy acibenzolar (Ref: CGA 323060)
Note: Not toxicologically relevant

Plant

ECOTOXICOLOGY

Property

Value

Source; quality score; and other information

Interpretation

Bio-concentration factor

BCF (l kg⁻¹)

117

Whole fish

Threshold for concern

CT₅₀ (days)

0.35

Mammals - Acute oral LD₅₀ (mg kg⁻¹)

> 2000

Rat

Low

Mammals - Short term dietary NOEL

(mg kg⁻¹)

Rat

(ppm diet)

200

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

Birds - Acute LD₅₀ (mg kg⁻¹)

> 2000

Colinus virginianus

Low

Birds - Short term dietary (LC₅₀/LD₅₀)

> 5200 ppm

Colinus virginianus

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

Fish - Acute 96 hour LC₅₀ (mg l⁻¹)

0.4

Oncorhynchus mykiss

Moderate

Fish - Chronic 21 day NOEC (mg l⁻¹)

0.026

Oncorhynchus mykiss

Moderate

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

2.4

Daphnia magna

Moderate

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

0.044

Daphnia magna

Moderate

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

0.88

Mysidopsis bahia

Moderate

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 - Acute 7 day EC₅₀, biomass (mg l⁻¹)

0.31

Lemna gibba

Moderate

Non-target plants

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

0.5

Scenedemus subspicatus 72 hour

Moderate

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

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)

> 128

Apis mellifera

Low

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

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 pollinators (1)

Acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg insect⁻¹)

Mode of exposure

Other pollinators (2)

Acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg insect⁻¹)

Mode of exposure

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

> 500

Eisenia foetida corr

Moderate

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

1.34

Eisenia foetida corr

Moderate

Other soil macro-organisms

Acute LC₅₀ (mg kg⁻¹)

Chronic NOEC (mg kg⁻¹)

Other arthropod (1)

LR₅₀ g ha⁻¹

200

>
Aphidius rhopalosphi

% Effect

-4

Mortality / Parasitism [Dose: 0.03 kg ha⁻¹]
Aphidius matricariae adult female

Other arthropod (2)

LR₅₀ g ha⁻¹

200

>
Typhlodromus pyri

% Effect

15.6

Mortality and Fecundity [Dose: 0.03 kg ha⁻¹]
Typhlodromus pyri adult and protonymph

Soil micro-organisms

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

Dose: Not stated

Mesocosm study data

NOEAEC mg l⁻¹

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)

2000

Rat

Mammals - Inhalation LC₅₀ (mg l⁻¹)

> 5.0

Rat 4hr (nose only)

Other Mammal toxicity endpoints

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

0.1

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

None allocated

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

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

0.1

Dermal penetration studies (%)

0.1-33

concentration dependent

Dangerous Substances Directive 76/464

Exposure Routes

Public

Minimal risk of dietary exposure
Negligible risk to bystanders

Occupational

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

European MRLs

EU MRL pesticide database

Drinking Water Standards

Drinking Water MAC (μg l⁻¹)

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

Eye irritant

Phototoxicant

No data found

General human health issues

Possible skin sensitiser
Weak evidence of clastogenicity

Handling issues

Property

Value and interpretation

General

Not explosive or oxidising
IMDG Transport class 9

CLP classification 2013

Health: H315, H317, H319, H335
Environment: H400, H410

EC Risk Classification

Xn - Harmful: R43
Xi - Irritant: R36/37/38
N - Dangerous for the environment: R50, R53

EC Safety Classification

S36, S37, S60, S61, S63

WHO Classification

NL (Not listed)

UN Number

3082

Waste disposal & packaging

Packaging Group III (minor danger)

TRANSLATIONS

Language

Name

English

acibenzolar-S-methyl

French

acibenzolar-S-methyl

German

Acibenzolar-S-methyl

Danish

acibenzolar-S-methyl

Italian

acibenzolar-S-metile

Spanish

acibenzolar-S-metil

Greek

Polish

acybenzolar-S metylowy

Swedish

Hungarian

acibenzolar S-metil

Dutch

Record last updated:	12/01/2021
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