methomyl (Ref: OMS 1196) ** DPX X1179 ** Translations

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SUMMARY

Methomyl is an oxime carbamate insecticide currently approved for use in the EU. It is highly soluble in water but has a low volatility and would not normally be expected to leach to groundwater. It is not normally persistent in soil or water systems. It is highly toxic to mammals and a cholinesterase inhibitor. It shows a moderate to high toxicity to most fauna and flora.

GENERAL INFORMATION
for methomyl

Description: An insecticide used to control a wide range of foliar and soil-borne insects. Also a pesticide transformation product

Example pests controlled: Lepidoptera, Coleoptera and Diptera

Example applications: Lettuce; Artichokes; Rhubarb; Orchard crops; Sod turf; Alfalfa; Sugarbeet; Cotton

Efficacy & activity: -

Availability status: Current

Introduction & key dates: First registered in the United States in 1968

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

Status	Approved
Dossier rapporteur/co-rapporteur	Belgium/Romania
Date inclusion expires	31/08/2019
EU Candidate for substitution (CfS)	Yes - low ADI / ARfD / AOEL
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, USA

Chemical structure:

Isomerism	Isomeric - cis-isomer is strongly favored thermodynamically
Chemical formula	C5H10N2O2S
Canonical SMILES	CC(=NOC(=O)NC)SC
Isomeric SMILES	C/C(=N\OC(=O)NC)/SC
International Chemical Identifier key (InChIKey)	UHXUZOCRWCRNSJ-UHFFFAOYSA-N
International Chemical Identifier (InChI)	InChI=1S/C5H10N2O2S/c1-4(10-3)7-9-5(8)6-2/h1-3H3,(H,6,8)/b7-4+
2D structure diagram/image available?	Yes

Cambridge Crystallographic Data Centre diagrams:

Common Name	Relationship	Link
Methomyl	Unstated isomer
(E)-methomyl	(E)-isomer
(Z)-methomyl	(Z)-isomer

General status:

Pesticide type	Insecticide, Acaricide, Metabolite
Metabolite Type	Soil, Animal, Water, Plant
Substance group	Carbamate
Minimum active substance purity	980 g/kg
Known relevant impurities	EU dossier - None declared
Substance origin	Synthetic
Mode of action	Systemic with contact and stomach action. Cholinesterase inhibitor.
CAS RN	16752-77-5
EC number	240-815-0
CIPAC number	264
US EPA chemical code	090301
PubChem CID	5353758
Molecular mass (g mol-1)	162.21
PIN (Preferred Identification Name)	-
IUPAC name	S-methyl (EZ)-N-(methylcarbamoyloxy)thioacetimidate
CAS name	methyl N-(((methylamino)carbonyl)oxy)ethanimidothioate
Other status information	Marine Pollutant; Chemical subject to PIC regulations
Relevant Environmental Water Quality Standards	-
Herbicide Resistance Classification (HRAC)	Not applicable
Herbicide Resistance Classification (WSSA)	Not applicable
Insecticide Resistance Classification (IRAC)	1A
Fungicide Resistance Classification (FRAC)	Not applicable
Examples of recorded resistance	Aphis gossypii Bemisia tabaci Chrysoperla carnea Earias vittella Frankliniella occidentalis Heliothis assulta many more
Physical state	White crystalline solid
Related substances & organisms	-

Can be a metabolite of:

Parent		Formation medium	Estimated maximum occurrence fraction	1107/2009 relevancy
thiodicarb		Soil	0.800	Major fraction, Relevant
alanycarb		Soil		-

Formulations:

Property	Value
Example manufacturers & suppliers of products using this active now or historically	AgroCare Bayer CropScience FCC
Example products using this active	Methomyl 20SC Lannate Lanox Nudrin Metofan
UK LERAP status	No UK approval for use as a pesticide under EC Regulation 1107/2009
Formulation and application details	Often supplied as a soluble concentrate or emulsifiable concentrate. May be applied aerially in the US.

ENVIRONMENTAL FATE
for methomyl

Property		Value	Source/Quality Score/Other Information	Interpretation
Solubility - In water at 20oC (mg l-1)		55000	A5	High
Solubility - In organic solvents at 20oC (mg l-1)		97100	A5 - n-Heptane	-
		250000	A5 - Acetone	-
		1000000	L3 - Methanol	-
		420000	L3 - Ethanol	-
Melting point (oC)		79.6	A5	-
Boiling point (oC)		Decomposes before boiling	A5	-
Degradation point (oC)		192	A5	-
Flashpoint (oC)		Not expected to self ignite; Not highly flammable	A5	-
Octanol-water partition coefficient at pH 7, 20oC	P	1.23 X 1000	Calculated	-
	Log P	0.09	A5	Low
Bulk density (g ml-1)/Specific gravity		1.32	A5	-
Dissociation constant (pKa) at 25oC		Not applicable	A5 -	-
		Note: No dissociation
Vapour pressure at 20oC (mPa)		0.72	A5	Low volatility
Henry's law constant at 25oC (Pa m3 mol-1)		2.13 X 10-06	A5	Non-volatile
GUS leaching potential index		2.19	Calculated	Transition state
SCI-GROW groundwater index (μg l-1) for a 1 kg ha-1 or 1 l ha-1 application rate	Value	1.45 X 10-02	Calculated	-
	Note	-
Potential for particle bound transport index		-	Calculated	Low
Maximum UV-vis absorption L mol-1 cm-1		Neutral solution: 234nm = 9010; [Acidic solution: 234nm = 8980; [Basic solution: 234nm = 8890	A5	-
Surface tension (mN m-1)		73.7	A5 at 20.1oC	-

Degradation:

Property		Value	Source/Quality Score/Other Information	Interpretation
General biodegradability		-
Soil degradation (days) (aerobic)	DT50 (typical)	7	A5	Non-persistent
	DT50 (lab at 20oC)	6.97	A5	Non-persistent
	DT50 (field)	-	-	-
	DT90 (lab at 20oC)	25.3	A5	-
	DT90 (field)	-	-	-
	DT50 modelling endpoint	-	-	-
	Note	EU dossier lab studies DT50 range 4.6-8.6 days, DT90 range 15.4-38.2 days; Other sources: DT50 30 days (DW4)
Dissipation rate RL50 on plant matrix	Value	3.0	R4	-
	Note	Published literature RL50 range 0.5-8.7 days, 8 field & undercover grown crops, various matrices, n=14
Dissipation rate RL50 on and in plant matrix	Value	4.0	R4	-
	Note	Published literature RL50 range 0.9-6.4 days, 13 field & undercover grown crops, various matrices, n=14
Aqueous photolysis DT50 (days) at pH 7	Value	Stable	A5	-
	Note	-
Aqueous hydrolysis DT50 (days) at 20oC and pH 7	Value	Stable	A5	-
	Note	Stable pH 5 to pH 7, DT50 36 days at pH 9, all at 25 deg C
Water-sediment DT50 (days)		3.7	A5	Fast
Water phase only DT50 (days)		2.9	A5	Moderately fast

Soil adsorption and mobility:

Property		Value	Source/Quality Score/Other Information	Interpretation
Linear	Kd	-	DW3	Mobile
	Koc	72
	Notes and range	-
Freundlich	Kf	0.381	A5	Mobile
	Kfoc	25.2
	1/n	0.86
	Notes and range	EU dossier Kf range 0.145-0.809 mL/g, Kfoc range 13.3-42.8 mL/g, 1/n range 0.82-0.89, Soils=5
pH sensitivity		No

Key metabolites:

Metabolite		Formation medium	Estimated maximum occurrence fraction	1107/2009 relevancy
methomyl oxime (Ref: IN-X1177)		Soil	0.022	Minor fraction, Not relevant

Other known metabolites:

Metabolite name and reference	Aliases	Formation medium / Rate	Estimated maximum occurrence fraction	Metabolising enzymes
acetonitrile	-	Water/sediment; Soil; Rat (Blood, Liver)	-	-
acetamide	-	Animal; Rat	-	-
N-acetyl-S-[1-[[[(methylamino)carbonyl]oxy]imino]ethyl]-L-cysteine	methomyl mercapturate	Rat (Urinary)	-	-
E-methyl N-[[(methylamino)carbonyl]oxy]ethanimidothioate (Ref: IN-B1884)	anti-methomyl	Animal	-	-
methyl-N-[[[(hydroxymethyl)amino]carbonyl]oxy]ethanimidothioate (Ref: IN-G6520)	hydroxy methyl methomyl	Plant	-	-
9-hydroxy-6-methyl-3-oxo-4-oxa-7-thia-2,5-diazadec-5-en-10-oic acid (Ref: IN-HUZ57)	hydroxy cysteine of methomyl	Plant	-	-
2-methyl-4-thiazolemethanol (Ref: IN-NR282)	-	Plant	-	-

ECOTOXICOLOGY
for methomyl

Property		Value	Source/Quality Score/Other Information	Interpretation
Bio-concentration factor	BCF (l kg-1)	Low risk	A5 Based on LogP < 3	Low potential
	CT50 (days)	-		-
Mammals - Acute oral LD50 (mg kg-1)		30	A5 Rat	High
Mammals - Short term dietary NOEL	(mg kg-1)	6	A5 Rabbit	High
	(ppm diet)	-		-
Birds - Acute LD50 (mg kg-1)		24.2	A5 Colinus virginianus	High
Birds - Short term dietary (LC50/LD50)		> 518.8 mg kg bw-1 day-1	A5 Colinus virginianus	-
Fish - Acute 96 hour LC50 (mg l-1)		0.63	A5 Lepomis macrochirus	Moderate
Fish - Chronic 21 day NOEC (mg l-1)		0.076	A5	Moderate
Aquatic invertebrates - Acute 48 hour EC50 (mg l-1)		0.0076	J4 Daphnia magna	High
Aquatic invertebrates - Chronic 21 day NOEC (mg l-1)		0.0016	A5 Daphnia magna	High
Aquatic crustaceans - Acute 96 hour LC50 (mg l-1)		0.036	F3 Americamysis bahia	High
Sediment dwelling organisms - Acute 96 hour LC50 (mg l-1)		0.032	A5 Chironomus riparius	High
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)		-	-	-
Non-target plants		-	-	-
		-	-	-
Algae - Acute 72 hour EC50, growth (mg l-1)		> 100	A5 Selenastrum capricornutum	Low
Algae - Chronic 96 hour NOEC, growth (mg l-1)		-	-	-
Honeybees	Contact acute 48 hour LD50 (μg bee-1)	0.16	A5	High
	Oral acute 48 hour LD50 (μg bee-1)	0.28	A5	High
	Unknown mode acute 48 hour LD50 (μg bee-1)	-	-	-
Earthworms - Acute 14 day LC50 (mg kg-1)		19	A5 Eisenia foetida	Moderate
Earthworms - Chronic 14 day NOEC, reproduction (mg kg-1)		1.5	A5 Eisenia foetida	Moderate
Other soil macro-organisms - e.g. Collembola	LR50 / EC50 / NOEC / % Effect	-	-	-
Other arthropod (1)	LR50 g ha-1	0.20	48 hour A5 Aphidius rhopalosiphi, adult	-
	% Effect	-	-	-
Other arthropod (2)	LR50 g ha-1	9.1	7 day A5 Typhlodromus pyri, protonymph	-
	% Effect	-	-	-
Soil micro-organisms		Nitrogen mineralisation: No significant adverse effect Carbon mineralisation: No significant adverse effect	A5 Dose: 4.5 kg ha-1, 28 days	-
Mesocosm study data	NOEAEC mg l-1	-	-	-
	NOEAEC mg l-1	-	-	-

HUMAN HEALTH AND PROTECTION
for methomyl

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)		30	A5 Rat	High
Mammals - Dermal LD50 (mg kg-1 body weight)		> 2000	A5 Rat	-
Mammals - Inhalation LC50 (mg l-1)		0.215	A5 Rat	-
Other Mammal toxicity endpoints		-		-
ADI - Acceptable Daily Intake (mg kg-1bw day-1)		0.0025	A5 Rat, SF=100	-
ARfD - Acute Reference Dose (mg kg-1bw day-1)		0.0025	A5 Rat, 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)		0.0025	A3 Rat, SF=100	-
Dermal penetration studies (%)		1.2-15.0	A5 concentration dependent	-
Dangerous Substances Directive 76/464		-	-	-
Exposure Limits		-	-	-
Exposure Routes	Public	No unacceptable risks to bystanders identified
	Occupational	Risk of expsoure via dermal absortption 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)		-	-	-

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		Possible thyroid toxicant Endocrine issues - Weak increase of aromatase activity and estrogen production

: 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 IMDG Transport Code is usually 6.1
CLP classification 2013		Health: H300 Environment: H400, H410
EC Risk Classification		T+ - Very toxic: R28 N - Dangerous for the environment: R50, R53
EC Safety Classification		S1/2, S22, S36/37, S45, S60, S61
WHO Classification		Ib	-	Highly hazardous
US EPA Classification (formulation)		I (oral, eye), II (inhalation), III (dermal)	-	Danger - Highly toxic, Warning - Moderately toxic, Caution - Slightly toxic
UN Number		2757
Waste disposal & packaging		Packaging Group II (medium danger)

TRANSLATIONS
for methomyl

Language	Name
English	methomyl
French	methomyl
German	Methomyl
Danish	methomyl
Italian	metomil
Spanish	metomilo
Greek	methomyl
Slovenian	metomil
Polish	metomyl
Swedish	metomyl
Hungarian	metomil
Dutch	methomyl

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Record last updated: Wednesday 31 October 2018
Contact: aeru@herts.ac.uk