Emamectin B1a	Last updated: 13/02/2026
(Also known as: abamectin-aminomethyl B1a)

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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
		Human health High alert: Mammals acute toxicity: High	Highly Hazardous Pesticide (HHP) Type II alert

GENERAL INFORMATION

Description	A naturally occuring soil Actinomycete effective against various insect pests
Example pests controlled	Caterpillars; Mites; Thrips; Leaf miners
Example applications	Fruit trees; Leafy crops including lettuce, brassicas
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 plant protection agent

EC Regulation 1107/2009 (repealing 91/414)

EC Regulation 1107/2009 status	Approved
Dossier rapporteur/co-rapporteur	Netherlands
Date EC 1107/2009 inclusion expires	15/11/2026
EU Candidate for substitution (CfS)	Yes - low ADI/ARfD/AOEL
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	-

Chemical structure

Isomerism	Emamectin B1a exhibits complex stereoisomerism due to its large, polycyclic structure and numerous chiral centres. The molecule contains multiple asymmetric carbon atoms, each capable of adopting either R or S configuration, which gives rise to a specific three-dimensional arrangement essential for its biological activity. Emamectin B1a also includes conjugated double bonds, which introduce geometric (E/Z) isomerism. The biologically active form used in veterinary medicine is a single stereoisomer, carefully controlled during synthesis to maintain efficacy and safety.
Chemical formula	C₄₉H₇₅NO₁₃
Canonical SMILES	CCC(C)C1C(C=CC2(O1)CC3CC(O2)CC=C(C(C(C=CC=C4COC5C4(C(C=C(C5O)C)C(=O)O3)O)C)OC6CC(C(C(O6)C)OC7CC(C(C(O7)C)NC)OC)OC)C)C
Isomeric SMILES	CC[C@H](C)[C@@H]1[C@H](C=C[C@@]2(O1)C[C@@H]3C[C@H](O2)C/C=C(/[C@H]([C@H](/C=C/C=C/4\CO[C@H]5[C@@]4([C@@H](C=C([C@H]5O)C)C(=O)O3)O)C)O[C@H]6C[C@@H]([C@H]([C@@H](O6)C)O[C@H]7C[C@@H]([C@@H]([C@@H](O7)C)NC)OC)OC)\C)C
International Chemical Identifier key (InChIKey)	CXEGAUYXQAKHKJ-COFQVFHOSA-N
International Chemical Identifier (InChI)	InChI=1S/C49H75NO13/c1-12-26(2)44-29(5)18-19-48(63-44)24-35-21-34(62-48)17-16-28(4)43(27(3)14-13-15-33-25-56-46-42(51)30(6)20-36(47(52)59-35)49(33,46)53)60-40-23-38(55-11)45(32(8)58-40)61-39-22-37(54-10)41(50-9)31(7)57-39/h13-16,18-20,26-27,29,31-32,34-46,50-51,53H,12,17,21-25H2,1-11H3/b14-13+,28-16+,33-15+/t26-,27-,29-,31-,32-,34+,35-,36-,37-,38-,39-,40-,41+,42+,43-,44+,45-,46+,48+,49+/m0/s1
2D structure diagram/image available?	Yes

General status

Biopesticide type		Fungicide; Other substance; Veterinary substance
Other bioactivity & uses		Bactericide
Substance groups		Micro-organism derived substance
Minimum active substance purity		-
Known relevant impurities		-
Substance origin		Natural
Mode of action		Non-systemic, acts by causing insect paralysis. Glutamate-gated chloride channel (GluCl) allosteric modulator.
Substance source		Produced by the fermentation of the soil actinomycete Streptomyces avermitilis
Uses		Crop protection
Target pests		Caterpillars; Mites; Thrips; Leaf miners
Target host		Fruit trees; Leafy crops including lettuce, brassicas
Farming system suitability		-
CAS RN		121124-29-6
EC number		-
CIPAC number		791
US EPA chemical code		-
PubChem CID		-
Molecular mass		886.1
PIN (Preferred Identification Name)		-
IUPAC name		(10E,14E,16E)-(1R,4S,5S,6S,6R,8R,12S,13S,20R,21R,24S)-6-[(S)-secbutyl]-21,24-dihydroxy-5,11,13,22-tetramethyl-2-oxo-(3,7,19-trioxatetracyclo[15.6.1.1.0]pentacosa-10,14,16,22-tetraene)-6-spiro-2Œ-(5,6-dihydro-2H-pyran)-12-yl 2,6-dideoxy-3-O-methyl-4-O-(2,4,6-trideoxy-3-O-methyl-4-methylamino-α-L-lyxo-hexapyranosyl)-)α-L-arabino-hexapyranoside
CAS name		(4R)-5-O-demethyl-4-deoxy-4-(methylamino)avermectin A1a
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	Yes [ R12 Rule 12: Pesticide active ingredients that are bioaccumulative (where bio-concentration factor (BCF) > 2000 l kg⁻¹ (if BCF is not available, where Log P >=5)) ]
Other status information		-
Herbicide Resistance Class (HRAC MoA class)		Not applicable
Herbicide Resistance Class (WSSA MoA class)		Not applicable
Insecticide Resistance Class (IRAC MoA class)		6
Fungicide Resistance Class (FRAC MOA class)		BM02
Examples of recorded resistance		-
Physical state		White or faintly yellow powder
Related substances & organisms		emamectin benzoate emamectin B1b

Commercial

Property	Value
Availability status	Current
Introduction & key dates	1997, introduced Israel and Japan; 1999, introduced USA
Example manufacturers & suppliers of products using this active now or historically	Syngenta AG MSD Animal Health UK Ltd
Example products using this active	Tree-age Proclaim Affirm Denim Rivaive Slice 2 Premix
Formulation and application details	Usually formulated as the benzoate. It is usually supplied as an emulsifiable concentrate and soluble granules for crops & as a trunk injection for trees. Often used as medicated pre-mix feed for animal health.
Commercial production	Emamectin B1a is produced commercially through a multi-step chemical synthesis process. The process begins with the fermentation of a specific strain of the bacterium Streptomyces avermitilis, which produces avermectin B1a as a secondary metabolite. The avermectin B1a is then chemically modified to produce emamectin B1a. This involves several steps, including oxidation and amination reactions. The resulting emamectin B1a is purified to remove any impurities and by-products. This is typically done using high-performance liquid chromatography (HPLC) or other purification techniques.
Impact on climate of production and use	There is no publicly available LCA data on GHG emissions specifically for the manufacture of emamectin B1a. However, based on similar fermentation-derived fungicides and estimated GHG emissions: are in the region of 10–25 kg CO₂e per kg of emamectin B1a

ENVIRONMENTAL FATE

Property		Value	Source; quality score; and other information	Interpretation
Solubility - In water at 20 °C at pH 7 (mg l⁻¹)		21	A4 A = EU regulatory and evaluation data as published by EC, EFSA (RAR, DAR & Conclusion dossiers), EMA (e.g. EU Annex III PIC DGD) (EU - Pesticides database; EFSA Scientific Publications ) 4 = Verified data	Moderate
Solubility - In organic solvents at 20 °C (mg l⁻¹)		-	-	-
Melting point (°C)		-	-	-
Boiling point (°C)		-	-	-
Degradation point (°C)		-	-	-
Flashpoint (°C)		-	-	-
Octanol-water partition coefficient at pH 7, 20 °C	P	1.00 X 1005	Calculated	-
	Log P	5.0	A5 A = EU regulatory and evaluation data as published by EC, EFSA (RAR, DAR & Conclusion dossiers), EMA (e.g. EU Annex III PIC DGD) (EU - Pesticides database; EFSA Scientific Publications ) 5 = Verified data used for regulatory purposes	High
Fat solubility of residues	Solubility	Soluble	A5 A = EU regulatory and evaluation data as published by EC, EFSA (RAR, DAR & Conclusion dossiers), EMA (e.g. EU Annex III PIC DGD) (EU - Pesticides database; EFSA Scientific Publications ) 5 = Verified data used for regulatory purposes	-
	Data type	Regulatory data - observed in metabolism and farm animal feeding studies	A5 A = EU regulatory and evaluation data as published by EC, EFSA (RAR, DAR & Conclusion dossiers), EMA (e.g. EU Annex III PIC DGD) (EU - Pesticides database; EFSA Scientific Publications ) 5 = Verified data used for regulatory purposes	-
Density (g ml⁻¹)		-	-	-
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		-
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	Kd (mL g⁻¹)	-	-	-
	Koc (mL g⁻¹)	-
	Notes and range	-
Freundlich	Kf (mL g⁻¹)	-	-	-
	Kfoc (mL g⁻¹)	-
	1/n	-
	Notes and range	-
pH sensitivity		-

Known soil metabolites

Metabolite	Major/Minor fraction	Estimated maximum occurrence fraction	Notes
8a-hydroxy-4-deoxy-4-epi-methylamino avermectin B1a (Ref: NOA 438306)	Major fraction	-	-
(4R)-5-O-demethyl-4-deoxy-4-(methylamino)-28-oxoavermectin A1a (Ref: NOA 438307)	Major fraction	-	-
N-nitroso MAB1a	Major fraction	-	-
(4R)-5-O-demethyl-4-deoxy-4-(formylmethylamino)-avermectin A1a (Ref: NOA 415692)	Major fraction	-	-

Known groundwater metabolites

None

Other known metabolites

None

ECOTOXICOLOGY

Terrestrial ecotoxicology

Property		Value	Source; quality score; and other information	Interpretation
Mammals - Acute oral LD₅₀ (mg kg⁻¹)		89.0	Q3 Q = Miscellaneous data from online sources 3 = Unverified data of known source Rat	High
Mammals - Short Term Oral NOAEL (mg kg⁻¹ bw d⁻¹)		-	-	-
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)		-	-	-
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	-	-	-
	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	8.9	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	No data	No data for 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)		High (class III)	-	-
Mammals - Acute oral LD₅₀ (mg kg⁻¹)		89.0	Q3 Q = Miscellaneous data from online sources 3 = Unverified data of known source Rat	High
Mammals - Short Term Oral NOAEL (mg kg⁻¹ bw d⁻¹)		-	-	-
Mammals - Long Term (Chronic) Oral NOAEL (mg kg⁻¹ bw d⁻¹)		-	-	-
Mammals - Dermal LD₅₀ (mg kg⁻¹ body weight)		-	-	-
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		Partially metabolised and excreted mainly in the faeces	F4 F = U.S. EPA ECOTOX database / U.S. EPA pesticide fate database / Miscellaneous WHO documents / FAO data, IPCS INCHEM data (US EPA Databases Related to Pesticide Risk Assessment ) 4 = Verified data	-

Health issues

Specific human health issues (hazard-based)		Carcinogen Genotoxic Endocrine disruptor XNo, known not to cause a problem A0 A = Chromosome aberration (EFSA database) 0 = No data ; B0 B = DNA damage/repair (EFSA database) 0 = No data ; C0 C = Gene mutation (EFSA database) 0 = No data ; D0 D = Genome mutation (EFSA database) 0 = No data ; E3 E = Unspecified genotoxicity type (miscellaneous data source) 3 = Negative No data found Reproduction / development effects Acetyl cholinesterase inhibitor Neurotoxicant ?Possibly, status not identified XNo, known not to cause a problem ?Possibly, status not identified Respiratory tract irritant Skin irritant Skin sensitiser No data found XNo, known not to cause a problem ?Possibly, status not identified Eye irritant Phototoxicant   ✓Yes, known to cause a problem No data found
General human health issues		May cause climical tremors

Handling issues

Property	Value and interpretation
General	Not explosive or oxidising Not explected to auto-ignite, Not highly flammable
CLP classification 2013	Health: H301, H311, H331, H372, H318, H319 Environment: H400
WHO Classification	II (Moderately hazardous)
UN Number	-
Waste disposal & packaging	-
Shelf-life, storage, stability and reactivity	-

TRANSLATIONS

Language	Name
English	emamectin B1a
French	-
German	-
Danish	-
Italian	-
Spanish	-
Greek	-
Polish	-
Swedish	-
Hungarian	-
Dutch	-
Norwegian	-

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Record last updated:	13/02/2026
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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