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Ancymidol (Ref: EL 531)
Last updated: 29/12/2020
(Also known as: ancymidole)

SUMMARY
Ancymidol is a plant growth regulator that is not approved for use in the EU. It is volatile and highly soluble in water. It is not persistent in soil systems and generally not persistent in water. It is moderately mobile and so there is a risk of leaching to groundwater under some conditions. It has a moderate mammalian toxicity but is not expected to bioaccumulate. Ancymidol is moderately toxic to fish, aquatic invertebrates, aquatic plants and honey bees. However it is less toxic to algae and birds.
GENERAL INFORMATION
Description
A plant growth inhibitor used to produce more compact horticultural, non-food plants
Example pests controlled
Growth - internodal elongation to improve plant shape
Example applications
Ornamentals particularly container grown herbaceous plants and woody shrubs
Efficacy & activity
-
Availability status
Current
Introduction & key dates
1973, USA
UK regulatory status
UK COPR regulatory status
Not approved
Date COPR inclusion expires
Expired
UK LERAP status
No UK approval for use
EC Regulation 1107/2009 (repealing 91/414)
EC Directive 1107/2009 status
Not approved
Dossier rapporteur/co-rapporteur
-
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
                 
Also used in
Also used in
USA
Chemical structure
Isomerism
A chiral molecule
Chemical formula
C₁₅H₁₆N₂O₂
Canonical SMILES
COC1=CC=C(C=C1)C(C2CC2)(C3=CN=CN=C3)O
Isomeric SMILES
No data
International Chemical Identifier key (InChIKey)
HUTDUHSNJYTCAR-UHFFFAOYSA-N
International Chemical Identifier (InChI)
InChI=1S/C15H16N2O2/c1-19-14-6-4-12(5-7-14)15(18,11-2-3-11)13-8-16-10-17-9-13/h4-11,18H,2-3H2,1H3
2D structure diagram/image available?
Yes
Cambridge Crystallographic Data Centre diagrams
Common Name Relationship Link
ancymidol Unstated isomer
General status
Pesticide type
Plant growth regulator
Substance group
Pyrimidinyl carbinol
Minimum active substance purity
-
Known relevant impurities
-
Substance origin
Synthetic
Mode of action
Absorbed by leaves and roots, acts via the inhibition of gibberellin biosynthesis: Gibberellin antagonist
CAS RN
12771-68-5
EC number
235-814-7
CIPAC number
8017
US EPA chemical code
108601
PubChem CID
25572
Molecular mass
256.30
PIN (Preferred Identification Name)
rac-(R)-cyclopropyl(4-methoxyphenyl)(pyrimidin-5-yl)methanol
IUPAC name
(RS)-α-cyclopropyl-4-methoxy-α-(pyrimidin-5-yl)benzyl alcohol
CAS name
α-cyclopropyl-α-(4-methoxyphenyl)-5-pyrimidinemethanol
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 applicable
Fungicide Resistance Classification (FRAC)
Not applicable
Examples of recorded resistance
-
Physical state
White crystalline solid
Formulations
Property
Value
Example manufacturers & suppliers of products using this active now or historically
  • Quel
  • A-rest
  • Reducymol
Example products using this active
  • Fine Chemicals
  • Sepro Corp
  • Elanco
Formulation and application details
Usually supplied as a soluble concentrate
ENVIRONMENTAL FATE
Property
Value
Source; quality score; and other information
Interpretation
Solubility - In water at 20 °C (mg l⁻¹)
650
H4 H = The US ARS pesticide properties database (click here )
4 = Verified data
High
Solubility - In organic solvents at 20 °C (mg l⁻¹)
250000
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Methanol
-
250000
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Acetone
-
37000
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Hexane
-
Melting point (°C)
110.5
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
-
Boiling point (°C)
Decomposes before boiling
F4 F = U.S. EPA ECOTOX database / U.S. EPA pesticide fate database / Miscellaneous WHO documents (US EPA Databases Related to Pesticide Risk Assessment )
4 = Verified data
-
Degradation point (°C)
- - -
Flashpoint (°C)
Not expected to self ignite; Not highly flammable
F4 F = U.S. EPA ECOTOX database / U.S. EPA pesticide fate database / Miscellaneous WHO documents (US EPA Databases Related to Pesticide Risk Assessment )
4 = Verified data
-
Octanol-water partition coefficient at pH 7, 20 °C
P
8.13 X 1001 Calculated -
Log P
1.91
H4 H = The US ARS pesticide properties database (click here )
4 = Verified data
Low
Bulk density (g ml⁻¹)
0.42
F4 F = U.S. EPA ECOTOX database / U.S. EPA pesticide fate database / Miscellaneous WHO documents (US EPA Databases Related to Pesticide Risk Assessment )
4 = Verified data
-
Dissociation constant pKa) at 25 °C
- - -
-
Vapour pressure at 20 °C (mPa)
0.13
H4 H = The US ARS pesticide properties database (click here )
4 = Verified data
Low volatility
Henry's law constant at 25 °C (Pa m³ mol⁻¹)
1.58 X 10-06
H4 H = The US ARS pesticide properties database (click here )
4 = Verified data
Non-volatile
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)
15
H4 H = The US ARS pesticide properties database (click here )
4 = Verified data
Non-persistent
DT₅₀ (lab at 20 °C)
120
Q3 Q = Miscellaneous internet resources
3 = Unverified data of known source
Persistent
DT₅₀ (field)
15
H4 H = The US ARS pesticide properties database (click here )
4 = Verified data
Non-persistent
DT₉₀ (lab at 20 °C)
- - -
DT₉₀ (field)
- - -
DT₅₀ modelling endpoint
- - -
Note
Some studies quote DT₅₀ as high as 120 days (US3)
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
- - -
Note
-
Aqueous hydrolysis DT₅₀ (days) at 20 °C and pH 7
Value
30
W4 W = French database provided by ARVALIS-Institut du Végétal
4 = Verified data
Moderately persistent
Note
Hydrolysis is not pH sensitive in range 5-9, 25 °C
Water-sediment DT₅₀ (days)
- - -
Water phase only DT₅₀ (days)
- - -
Soil adsorption and mobility
Property
Value
Source; quality score; and other information
Interpretation
Linear
Kd
-
H3 H = The US ARS pesticide properties database (click here )
3 = Unverified data of known source
Moderately mobile
Koc
83
Notes and range
Best available data
Freundlich
Kf
- - -
Kfoc
-
1/n
-
Notes and range
-
pH sensitivity
-
Fate indices
Property
Value
Source; quality score; and other information
Interpretation
GUS leaching potential index
2.45 Calculated Transition state
SCI-GROW groundwater index (μg l⁻¹) for a 1 kg ha⁻¹ or 1 l ha⁻¹ application rate
Value
9.19 X 10-02 Calculated -
Note
-
Potential for particle bound transport index
Low Calculated -
Potential for loss via drain flow
Moderately mobile Calculated -
ECOTOXICOLOGY
Property
Value
Source; quality score; and other information
Interpretation
Bio-concentration factor
BCF (l kg⁻¹)
8.38
Q2 Q = Miscellaneous internet resources
2 = Unverified data of unknown source
Estimated
Low potential
CT₅₀ (days)
Not available -
Mammals - Acute oral LD₅₀ (mg kg⁻¹)
1721
F4 F = U.S. EPA ECOTOX database / U.S. EPA pesticide fate database / Miscellaneous WHO documents (US EPA Databases Related to Pesticide Risk Assessment )
4 = Verified data
Rat
Moderate
Mammals - Short term dietary NOEL
(mg kg⁻¹)
-
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Rat
-
(ppm diet)
8000 -
Mammals - Chronic 21d NOAEL (mg kg⁻¹ bw d⁻¹)
- - -
Birds - Acute LD₅₀ (mg kg⁻¹)
5192
F2 F = U.S. EPA ECOTOX database / U.S. EPA pesticide fate database / Miscellaneous WHO documents (US EPA Databases Related to Pesticide Risk Assessment )
2 = Unverified data of unknown source
Colinus virginianus
Low
Birds - Short term dietary (LC₅₀/LD₅₀)
- - -
Birds - Chronic 21d NOEL (mg kg⁻¹ bw d⁻¹)
- - -
Fish - Acute 96 hour LC₅₀ (mg l⁻¹)
> 100
F4 F = U.S. EPA ECOTOX database / U.S. EPA pesticide fate database / Miscellaneous WHO documents (US EPA Databases Related to Pesticide Risk Assessment )
4 = Verified data
Oncorhynchus mykiss
Low
Fish - Chronic 21 day NOEC (mg l⁻¹)
- - -
Aquatic invertebrates - Acute 48 hour EC₅₀ (mg l⁻¹)
> 100
F4 F = U.S. EPA ECOTOX database / U.S. EPA pesticide fate database / Miscellaneous WHO documents (US EPA Databases Related to Pesticide Risk Assessment )
4 = Verified data
Daphnia magna
Low
Aquatic invertebrates - Chronic 21 day NOEC (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 - Acute 7 day EC₅₀, biomass (mg l⁻¹)
0.193
F3 F = U.S. EPA ECOTOX database / U.S. EPA pesticide fate database / Miscellaneous WHO documents (US EPA Databases Related to Pesticide Risk Assessment )
3 = Unverified data of known source
Lemna gibba
Moderate
Non-target plants
- - -
- - -
Algae - Acute 72 hour EC₅₀, growth (mg l⁻¹)
26.9
F3 F = U.S. EPA ECOTOX database / U.S. EPA pesticide fate database / Miscellaneous WHO documents (US EPA Databases Related to Pesticide Risk Assessment )
3 = Unverified data of known source
Pseudokirchneriella subcapitata
Low
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
F4 F = U.S. EPA ECOTOX database / U.S. EPA pesticide fate database / Miscellaneous WHO documents (US EPA Databases Related to Pesticide Risk Assessment )
4 = Verified data
Low
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)
- - -
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)
- - -
Earthworms - Chronic NOEC, reproduction (mg kg⁻¹)
- - -
Other soil macro-organisms
Acute LC₅₀ (mg kg⁻¹)
- - -
Chronic NOEC (mg kg⁻¹)
- - -
Other arthropod (1)
LR₅₀ g ha⁻¹
- - -
% Effect
- - -
Other arthropod (2)
LR₅₀ g ha⁻¹
- - -
% Effect
- - -
Soil micro-organisms
- - -
Mesocosm study data
NOEAEC mg l⁻¹
- - -
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)
1721
F4 F = U.S. EPA ECOTOX database / U.S. EPA pesticide fate database / Miscellaneous WHO documents (US EPA Databases Related to Pesticide Risk Assessment )
4 = Verified data
Rat
Moderate
Mammals - Dermal LD₅₀ (mg kg⁻¹ body weight)
200
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Rabbit
-
Mammals - Inhalation LC₅₀ (mg l⁻¹)
5.6
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Rat
-
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
Due to usage pattern the risk to bystanders and consumers is negligible
Occupational
-
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
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
;
E0 E = Unspecified genotoxicity type (miscellaneous data source)
0 = No data
?Possibly, status not identified
Reproduction / development effects Acetyl cholinesterase inhibitor Neurotoxicant
XNo, known not to cause a problem
XNo, known not to cause a problem
No data found
Respiratory tract irritant Skin irritant Skin sensitiser
No data found
XNo, known not to cause a problem
No data found
Eye irritant Phototoxicant  
Yes, known to cause a problem
No data found  
General human health issues
Moderately toxic
May cause respiratory problems
Physical dependence may develop
Handling issues
Property
Value and interpretation
General
Incompatible with strong oxidizing agents and acids
CLP classification 2013
Not classified: Obsolete
EC Risk Classification
Xn - Harmful: R20/21/22
EC Safety Classification
S24/25, S36/37/39
WHO Classification
III (Slightly hazardous)
UN Number
-
Waste disposal & packaging
-
TRANSLATIONS
Language
Name
English
ancymidol
French
ancymidole
German
Ancymidol
Danish
ancymidol
Italian
ancimidol
Spanish
ancimidol
Greek
-
Polish
ancymidol
Swedish
-
Hungarian
-
Dutch
-

Record last updated: 29/12/2020
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