isoxaben (Ref: EAF 496) ** benzamizole ** benzamidazole ** EL 107 ** Translations

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GENERAL INFORMATION
for isoxaben

Description: A broad-spectrum pre-emergence soil-acting amide herbicide for use mainly with grass and fruit to control broad-leaved weeds

Example pests controlled: Broad-leaved weeds including marestail, hairy fleabane, mallow, Shepherd's purse, henbit, checkweed, sowthistle

Example applications: Tree-nut plantations; Orchards; Vinyards; Ornamental trees and shrubs; Winter cereals

Efficacy & activity: -

Availability status: Current

Introduction & key dates: 1984, France

EC Regulation 1107/2009 (repealing 91/414):

Status	Approved
Dossier rapporteur/co-rapporteur	Austria/Finland
Date inclusion expires	31/05/2021
EU Candidate for substitution (CfS)	No
Listed in EU database	Yes

Approved for use () or known to be used () in the following European countries:

AT

BE

BG

CY

CZ

DE

DK

EE

EL

ES

FI

FR

HR

HU

IE

IT

LT

LU

LV

MT

NL

PL

PT

RO

SE

SI

SK

UK

Also used in: Australia

Chemical structure:

Isomerism	Isomeric with the isomers typically comprising around 2% of the product
Chemical formula	C18H24N2O4
Canonical SMILES	CCC(C)(CC)C1=NOC(=C1)NC(=O)C2=C(C=CC=C2OC)OC
Isomeric SMILES	No data
International Chemical Identifier key (InChIKey)	PMHURSZHKKJGBM-UHFFFAOYSA-N
International Chemical Identifier (InChI)	InChI=1S/C18H24N2O4/c1-6-18(3,7-2)14-11-15(24-20-14)19-17(21)16-12(22-4)9-8-10-13(16)23-5/h8-11H,6-7H2,1-5H3,(H,19,21)
Structure diagram/image available?	Yes

General status:

Pesticide type	Herbicide
Substance group	Benzamide
Minimum active substance purity	910 g/kg
Known relevant impurities	EU dossier - toluene 3g/kg
Substance origin	Synthetic
Mode of action	Selective, disrupts root and stem development in germinating seeds. Inhibition of cell wall synthesis.
CAS RN	82558-50-7
EC number	407-190-8
CIPAC number	701
US EPA chemical code	125851
PubChem CID	73672
Molecular mass (g mol-1)	332.39
PIN (Preferred Identification Name)	-
IUPAC name	N-[3-(1-ethyl-1-methylpropyl)-1,2-oxazol-5-yl]-2,6-dimethoxybenzamide
CAS name	N-(3-(1-ethyl-1-methylpropyl)-5-isoxazolyl)-2,6-dimethoxybenzamide
Other status information	-
Relevant Environmental Water Quality Standards	-
Herbicide Resistance Classification (HRAC)	L
Herbicide Resistance Classification (WSSA)	21
Insecticide Resistance Classification (IRAC)	Not applicable
Fungicide Resistance Classification (FRAC)	Not known
Examples of recorded resistance	-
Physical state	Colourless crystalline solid or waxy powder
Related substances & organisms	terbuthylazine trifluralin

Formulations:

Property	Value
Example manufacturers & suppliers of products using this active now or historically	AgriGuard Dow AgroSciences Landseer Syngenta Elanco
Example products using this active	Fargro Axit Skirmish Flexidor 125 EAF-496
UK LERAP status	None
Formulation and application details	Often supplied as a suspension concentrate.

ENVIRONMENTAL FATE
for isoxaben

Property		Value	Source/Quality Score/Other Information	Interpretation
Solubility - In water at 20oC (mg l-1)		0.93	A5	Low
Solubility - In organic solvents at 20oC (mg l-1)		88000	A5 - Ethyl acetate	-
		270000	A5 - Acetone	-
		98000	A5 - Methanol	-
		4000	A5 - Xylene	-
Melting point (oC)		175.3	A5	-
Boiling point (oC)		Decomposes before boiling	A5	-
Degradation point (oC)		200	A4	-
Flashpoint (oC)		Not expected to self ignite; Not highly flammable	A5	-
Octanol-water partition coefficient at pH 7, 20oC	P	8.71 X 1003	Calculated	-
	Log P	3.94	L3	High
Bulk density (g ml-1)/Specific gravity		0.58	L3	-
Dissociation constant (pKa) at 25oC		9.78	A5	-
		Note: Weak acid
Vapour pressure at 20oC (mPa)		5.50 X 10-04	A5	Low volatility
Henry's law constant at 25oC (Pa m3 mol-1)		1.96 X 10-04	A5	Non-volatile
GUS leaching potential index		3.60	Calculated	High leachability
SCI-GROW groundwater index (μg l-1) for a 1 kg ha-1 or 1 l ha-1 application rate	Value	7.72 X 10-01	Calculated	-
	Note	-
Potential for particle bound transport index		-	Calculated	Medium
Maximum UV-vis absorption L mol-1 cm-1		Neutral solution: 252nm = 16500; [Acidic solution: 252nm = 16500; [Basic solution, 215nm = 11400, 275nm = 20800	A5	-
Surface tension (mN m-1)		72.9 +/- 0.18	A5 at 19oC	-

Degradation:

Property		Value	Source/Quality Score/Other Information	Interpretation
General biodegradability		-
Soil degradation (days) (aerobic)	DT50 (typical)	105	L3	Persistent
	DT50 (lab at 20oC)	301	A5	Persistent
	DT50 (field)	123	A5	Persistent
	DT90 (lab at 20oC)	1000	A5	-
	DT90 (field)	407	A5	-
	DT50 modelling endpoint	-	-	-
	Note	EU dossier lab studies DT50 range 127-891 days, DT90 range 421-2952 days; field studies DT50 range 66-309 days, DT90 range 219-1028 dats
Dissipation rate RL50 on plant matrix	Value	6.7	R4	-
	Note	Published literature RL50 range 5.0-8.4 days, 2 field crops, various matrices, n=2
Dissipation rate RL50 on and in plant matrix	Value	3.8	R3	-
	Note	Turf grass blades, n=1
Aqueous photolysis DT50 (days) at pH 7	Value	6	A5	Moderately fast
	Note	-
Aqueous hydrolysis DT50 (days) at 20oC and pH 7	Value	Stable	A5	-
	Note	Stable pH 5 to pH 9
Water-sediment DT50 (days)		16.8	A5	Fast
Water phase only DT50 (days)		8.8	A5	Moderately fast

Soil adsorption and mobility:

Property		Value	Source/Quality Score/Other Information	Interpretation
Linear	Kd	8.7	A5	Slightly mobile
	Koc	909
	Notes and range	EU dossier Kd range 6.43-12.6 mL/g, Koc range 700-1290 mL/g, Soils=4
Freundlich	Kf	3.3	A5	Moderately mobile
	Kfoc	354
	1/n	0.905
	Notes and range	EU dossier Kf range 0.81-6.63 mL/g, Kfoc range 190-570 mL/g, 1/n range 0.892-0.911, Soils=5
pH sensitivity		No

Key metabolites:

Metabolite		Formation medium	Estimated maximum occurrence fraction	1107/2009 relevancy
N-(3-(1-hydroxy-1-methyl-propyl)-5-isoxazolyl)-2,6,dimethoxybenzamide		Soil	0.108	Major fraction, Relevancy unknown
N-(3-(1-ethyl-1-methyl-2-oxypropyl)isoxazol-5-yl)-2,6-dimethoxybenzamide		Soil	0.073	Minor fraction, Relevancy unknown
N-(3-amino-4-ethyl-4-methyl-2-hexenoyl)-2,6-dimethoxybenzamide		Soil	0.60	Major fraction; Relevant
2,6-dimethoxybenzamide		Soil	0.129	Major fraction; Relevant

Other known metabolites:

Metabolite name and reference	Aliases	Formation medium / Rate	Estimated maximum occurrence fraction	Metabolising enzymes
6-(1-ethyl-1-methylpropyl)-2-(2-hydroxy-6-methoxyphenyl)-4-pyrimidinol Note: DT50 soil 47 days	methoxyphenyl pyrimidinol	Soil (Anaerobic)	0.331	-
2-hydroxy-6-methoxybenzamide	hydroxymethoxy benzamide	Water	-	-

ECOTOXICOLOGY
for isoxaben

Property		Value	Source/Quality Score/Other Information	Interpretation
Bio-concentration factor	BCF (l kg-1)	70.5	A5 Whole fish	Low potential
	CT50 (days)	0.49		-
Mammals - Acute oral LD50 (mg kg-1)		> 10000	A5 Rat	Low
Mammals - Short term dietary NOEL	(mg kg-1)	5.6	L2 Rat, 2 year	High
	(ppm diet)	-		-
Birds - Acute LD50 (mg kg-1)		> 2000	A5 Colinus virginianus	Low
Birds - Short term dietary (LC50/LD50)		> 937 mg kg bw-1 day-1	A5 Colinus virginianus	-
Fish - Acute 96 hour LC50 (mg l-1)		> 0.87	A5 Cyprinodon variegatus	Moderate
Fish - Chronic 21 day NOEC (mg l-1)		0.87	Q2 Oncorhynchus mykiss	Moderate
Aquatic invertebrates - Acute 48 hour EC50 (mg l-1)		> 1.3	A5 Daphnia magna	Moderate
Aquatic invertebrates - Chronic 21 day NOEC (mg l-1)		0.69	A5 Daphnia magna	Moderate
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)		8.0	A5 Chironomus riparius, development	Moderate
Sediment dwelling organisms - Chronic 28 day NOEC, sediment (mg kg-1)		-	-	-
Aquatic plants - Acute 7 day EC50, biomass (mg l-1)		0.011	A5 Lemna gibba	Moderate
Non-target plants		20	A5 Cocklebur Seedling emergence, ER50 as g/ha	-
		625	-	-
Algae - Acute 72 hour EC50, growth (mg l-1)		> 1.4	A5 Raphidocelis subcapitata	Moderate
Algae - Chronic 96 hour NOEC, growth (mg l-1)		> 1.4	A5 Selenastrum capricornutum	Low
Honeybees	Contact acute 48 hour LD50 (μg bee-1)	> 100	A5	Low
	Oral acute 48 hour LD50 (μg bee-1)	> 100	A5	Low
	Unknown mode acute 48 hour LD50 (μg bee-1)	-	-	-
Earthworms - Acute 14 day LC50 (mg kg-1)		> 500	A5 Eisenia foetida, corr	Moderate
Earthworms - Chronic 14 day NOEC, reproduction (mg kg-1)		3.34	A5 Eisenia foetida, corr	Moderate
Other soil macro-organisms - e.g. Collembola	LR50 / EC50 / NOEC / % Effect	-	-	-
Other arthropod (1)	LR50 g ha-1	1000	48 hour A5 Aphidius rhopalosiphi	-
	% Effect	-	-	-
Other arthropod (2)	LR50 g ha-1	1000	7 day A5 Typhlodromus pyri	-
	% Effect	-	-	-
Soil micro-organisms		Nitrogen mineralisation: No significant adverse effect Carbon mineralisation: No significant adverse effect	A5 Dose: 6.97 mg kg-1 soil, 28 days	-
Mesocosm study data	NOEAEC mg l-1	-	-	-
	NOEAEC mg l-1	-	-	-

HUMAN HEALTH AND PROTECTION
for isoxaben

General:

Property		Value	Source/Quality Score/Other Information	Interpretation
Threshold of Toxicological Concern (Cramer Class)		High (class III)	-	-
Mammals - Acute oral LD50 (mg kg-1)		> 10000	A5 Rat	Low
Mammals - Dermal LD50 (mg kg-1 body weight)		> 2000	A5 Rat	-
Mammals - Inhalation LC50 (mg l-1)		2.68	A5 Rat, 4 hr (nose only)	-
Other Mammal toxicity endpoints		-		-
ADI - Acceptable Daily Intake (mg kg-1bw day-1)		0.05	A5 SF=100	-
ARfD - Acute Reference Dose (mg kg-1bw day-1)		None allocated	A5 Dog, SF=100	-
AAOEL - Acute Acceptable Operator Exposure Level (mg kg-1 bw day-1)		-	-	-
AOEL - Acceptable Operator Exposure Level - Systemic (mg kg-1bw day-1)		0.25	A5 Dog, SF = 435	-
Dermal penetration studies (%)		6.6-16.7	A5 concentration dependent	-
Dangerous Substances Directive 76/464		-	-	-
Exposure Limits		-	-	-
Exposure Routes	Public	Negligible risk to bystanders Dietary exposure considered to be low risk
	Occupational	Risk of exposure acceptable under label recommendations for use for personal protection clothing and equipment
European MRLs		Click here for the EU MRL pesticide database
Drinking Water Standards		-	-	-
Drinking Water MAC (μg l-1)		0.1	EU Dir 89/778/EC limit; A5	-

Health issues:

Carcinogen	Mutagen	Endocrine disrupter	Reproduction / development effects	Cholinesterase inhibitor	Neurotoxicant
	-	-
Respiratory tract irritant	Skin irritant	Skin sensitiser	Eye irritant	Phototoxicant
		-		-
General human health issues		Bioaccumulates Possible liver toxicant USEPA - some evidence to suggest possible human carcinogen

: Yes, known to cause a problem
: No, known not to cause a problem
: Possibly, status not identified
- : No data found

Handling issues:

Property		Value	Source/Quality Score/Other Information	Interpretation
General		Not explosive or oxidising
CLP classification 2013		Environment: H413
EC Risk Classification		N - Dangerous for the environment: R50, R53
EC Safety Classification		S60, S61
WHO Classification		U	-	Unlikely to present an acute hazard
US EPA Classification (formulation)		IV	-	Caution - Not acutely toxic
UN Number		-
Waste disposal & packaging		-

TRANSLATIONS
for isoxaben

Language	Name
English	isoxaben
French	isoxaben
German	Isoxaben
Danish	isoxaben
Italian	isoxaben
Spanish	isoxaben
Greek	-
Slovenian	izoksaben
Polish	izoksaben
Swedish	isoxaben
Hungarian	-
Dutch	-

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Record last updated: Wednesday 23 May 2018
Contact: aeru@herts.ac.uk