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Thidiazuron (Ref: SN 49537)
(Also known as: TDZ)
SUMMARY
Data alerts

The following 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.

Environmental fate Ecotoxicity Human health
Environmental fate
Moderate alert:
Drainflow: Slightly mobile; Potential for particle bound transport: Medium
Ecotoxicity
Moderate alert:
Fish acute ecotoxicity: Moderate; Fish chronic ecotoxicity: Moderate; Daphnia acute ecotoxicity: Moderate; Daphnia chronic ecotoxicity: Moderate
Human health
Moderate alert:
Neurotoxicant
GENERAL INFORMATION
Description
A herbicide and defoliant plant growth regulator which stimulates ethylene production in some crops particularly cotton
Example pests controlled
Development of juvenille growth and regrowth; Vegetative growth
Example applications
Cotton; Mung beans; Melon
Efficacy & activity
-
Availability status
Current
Introduction & key dates
1982, 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 Regulation 1107/2009 status
Not approved
Dossier rapporteur/co-rapporteur
Not applicable
Date EC 1107/2009 inclusion expires
Expired
EU Candidate for substitution (CfS)
Not applicable
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
Australia, USA
Chemical structure
Isomerism
None
Chemical formula
C₉H₈N₄OS
Canonical SMILES
C1=CC=C(C=C1)NC(=O)NC2=CN=NS2
Isomeric SMILES
-
International Chemical Identifier key (InChIKey)
HFCYZXMHUIHAQI-UHFFFAOYSA-N
International Chemical Identifier (InChI)
InChI=1S/C9H8N4OS/c14-9(12-8-6-10-13-15-8)11-7-4-2-1-3-5-7/h1-6H,(H2,11,12,14)
2D structure diagram/image available?
Yes
General status
Pesticide type
Plant Growth Regulator, Herbicide, Other substance
Other constituent type
Disinfectant, Defoliant
Substance groups
Phenylurea herbicide; Urea herbicide; Thiadiazolylurea herbicide
Minimum active substance purity
>=95%
Known relevant impurities
-
Substance origin
Synthetic
Mode of action
Absorbed by leaves. A cytokine-active growth regulator. Inhibits the transmission of auxin and acts on plant cells that promote plant growth.
CAS RN
51707-55-2
EC number
257-356-7
CIPAC number
727
US EPA chemical code
120301
PubChem CID
40087
CLP index number
No data found
Molecular mass
220.25
PIN (Preferred Identification Name)
N-phenyl-N'-1,2,3-thiadiazol-5-ylurea
IUPAC name
1-phenyl-3-(1,2,3-thiadiazol-5-yl)urea
CAS name
N-phenyl-N'-1,2,3-thiadiazol-5-ylurea
Other status information
-
Relevant Environmental Water Quality Standards
-
Herbicide Resistance Classification (HRAC)
E
Herbicide Resistance Classification (WSSA)
14
Insecticide Resistance Classification (IRAC)
Not applicable
Fungicide Resistance Classification (FRAC)
Not applicable
Examples of recorded resistance
-
Physical state
White to pale yellow powder
Formulations
Property
Value
Example manufacturers & suppliers of products using this active now or historically
  • Aventis
  • Bayer CropScience
  • Nufarm Americas
  • Kingtai Chemicals
  • BOC Sciences
Example products using this active
  • Defolit
  • Freefall SC
Formulation and application details
Usually supplied as wettable powders and emulsifiable concentrates.
ENVIRONMENTAL FATE
Property
Value
Source; quality score; and other information
Interpretation
Solubility - In water at 20 °C (mg l⁻¹)
20
H4 H = The US ARS pesticide properties database. Dataset is no longer available.
4 = Verified data
 Low
Solubility - In organic solvents at 20 °C (mg l⁻¹)
2
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Hexane		 -
4200
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Methanol		 -
3
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Dichloromethane		 -
400
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Toluene		 -
Melting point (°C)
213
E4 E = Manufacturers safety data sheets
4 = Verified data
 -
Boiling point (°C)
- - -
Degradation point (°C)
- - -
Flashpoint (°C)
- - -
Octanol-water partition coefficient at pH 7, 20 °C
P
5.89 X 1001 Calculated -
Log P
1.77
V3 V = ChemID Online Databases; Chemspider; PubChem. (ChemID )
3 = Unverified data of known source
 Low
Fat solubility of residues
Solubility
- - -
Data type
- - -
Density (g ml⁻¹)
1.51
E4 E = Manufacturers safety data sheets
4 = Verified data
 -
Dissociation constant pKa) at 25 °C
8.86
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
 -
Weak acid
Vapour pressure at 20 °C (mPa)
3.00 X 10-06
H4 H = The US ARS pesticide properties database. Dataset is no longer available.
4 = Verified data
 Low volatility
Henry's law constant at 25 °C (Pa m³ mol⁻¹)
3.30 X 10-08
H4 H = The US ARS pesticide properties database. Dataset is no longer available.
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)
85
H4 H = The US ARS pesticide properties database. Dataset is no longer available.
4 = Verified data
 Moderately persistent
DT₅₀ (lab at 20 °C)
10
F3 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 )
3 = Unverified data of known source
 Non-persistent
DT₅₀ (field)
- - -
DT₉₀ (lab at 20 °C)
- - -
DT₉₀ (field)
- - -
DT₅₀ modelling endpoint
- - -
Note
Best available data
Dissipation rate RL₅₀ on plant matrix
Value
- - -
Note
-
Dissipation rate RL₅₀ on and in plant matrix
Value
2.5
R3 R = Peer reviewed scientific publications
3 = Unverified data of known source
 -
Note
Cotton leaves, n=1
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)
- - -
Soil adsorption and mobility
Property
Value
Source; quality score; and other information
Interpretation
Linear
Kd
-
H3 H = The US ARS pesticide properties database. Dataset is no longer available.
3 = Unverified data of known source
 Slightly mobile
Koc
742
Notes and range
Other sources: 110 mL g⁻¹ (DW4)
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
1.13 Calculated Low leachability
SCI-GROW groundwater index (μg l⁻¹) for a 1 kg ha⁻¹ or 1 l ha⁻¹ application rate
Value
1.55 X 10-02 Calculated -
Note
-
Potential for particle bound transport index
Medium Calculated -
Potential for loss via drain flow
Slightly mobile Calculated -
Bio-concentration factor
BCF (l kg⁻¹)
6.2
Q2 Q = Miscellaneous data from online sources
2 = Unverified data of unknown source
Estimated		 Low potential
CT₅₀ (days)
Not available -
Known metabolites

None
ECOTOXICOLOGY
Terrestrial ecotoxicology
Property
Value
Source; quality score; and other information
Interpretation
Mammals - Acute oral LD₅₀ (mg kg⁻¹)
> 5350
V3 V = ChemID Online Databases; Chemspider; PubChem. (ChemID )
3 = Unverified data of known source
Rat		 Low
Mammals - Short term dietary NOEL
(mg kg⁻¹)
-
Z2 Z = Kingtai Chemials website (click here )
2 = Unverified data of unknown source
Rat		 -
(ppm diet)
> 200 -
Mammals - Chronic 21d NOAEL (mg kg⁻¹ bw d⁻¹)
- - -
Birds - Acute LD₅₀ (mg kg⁻¹)
> 16000
V3 V = ChemID Online Databases; Chemspider; PubChem. (ChemID )
3 = Unverified data of known source
Phasianidae		 Low
Birds - Short term dietary (LC₅₀/LD₅₀)
- - -
Birds - Chronic 21d NOEL (mg kg⁻¹ bw d⁻¹)
- - -
Earthworms - Acute 14 day LC₅₀ (mg kg⁻¹)
- - -
Earthworms - Chronic NOEC, reproduction (mg kg⁻¹)
- - -
Soil micro-organisms
- - -
Collembola
Acute LC₅₀ (mg kg⁻¹)
- - -
Chronic NOEC (mg kg⁻¹)
- - -
Non-target plants
- - -
- - -
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)
105
F3 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 )
3 = Unverified data of known source
 Low
Chronic
- - -
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)
- - -
Aquatic ecotoxicology
Property
Value
Source; quality score; and other information
Interpretation
Fish - Acute 96 hour LC₅₀ (mg l⁻¹)
> 19
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
Oncorhynchus mykiss		 Moderate
Fish - Chronic 21 day NOEC (mg l⁻¹)
5.7
P3 P = Other non-EU, UK or US Governments and Regulators
3 = Unverified data of known source
Pimephales promelas		 Moderate
Aquatic invertebrates - Acute 48 hour EC₅₀ (mg l⁻¹)
> 10
J4 J = Pesticide Action Network database (click here )
4 = Verified data
Daphnia magna		 Moderate
Aquatic invertebrates - Chronic 21 day NOEC (mg l⁻¹)
0.1
F3 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 )
3 = Unverified data of known source
Daphnia magna LOEC		 Moderate
Aquatic crustaceans - Acute 96 hour LC₅₀ (mg l⁻¹)
2.8
F3 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 )
3 = Unverified data of known source
Americamysis 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)
24
F3 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 )
3 = Unverified data of known source
Lemna gibba 7 day		 Low
Algae - Acute 72 hour EC₅₀, growth (mg l⁻¹)
0.15
F2 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 )
2 = Unverified data of unknown source
Pseudokirchneriella subcapitata		 Moderate
Algae - Chronic 96 hour NOEC, growth (mg l⁻¹)
- - -
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)
> 5350
V3 V = ChemID Online Databases; Chemspider; PubChem. (ChemID )
3 = Unverified data of known source
Rat		 Low
Mammals - Dermal LD₅₀ (mg kg⁻¹ body weight)
1000
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Rat		 -
Mammals - Inhalation LC₅₀ (mg l⁻¹)
2.3
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Rat 4 hr		 -
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
-
MRLs
European
EU MRL pesticide database 
Great Britain
GB MRL Register 
Notes
-
Drinking Water Standards
- - -
Drinking Water MAC (μg l⁻¹)
- - -
Mammalian dose elimination route and rate
- - -
Health issues
Specific human health issues
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
;
E0 E = Unspecified genotoxicity type (miscellaneous data source)
0 = No data
 No data found
Reproduction / development effects Acetyl cholinesterase inhibitor Neurotoxicant
XNo, known not to cause a problem
XNo, known not to cause a problem
?Possibly, status not identified
Respiratory tract irritant Skin irritant Skin sensitiser
?Possibly, status not identified
?Possibly, status not identified
 No data found
Eye irritant Phototoxicant  
?Possibly, status not identified
 No data found  
General human health issues
No further information available
Handling issues
Property
Value and interpretation
General
Incompatible with strong oxidizing agents
CLP classification 2013
Health: H312, H315, H319, H332, H335
WHO Classification
III (Slightly hazardous)
UN Number
-
Waste disposal & packaging
-
Shelf-life, storage, stability and reactivity
Limited shelf-life. Store at 2-8 DegC
TRANSLATIONS
Language
Name
English
thidiazuron
French
thidiazuron
German
Thidiazuron
Danish
thidiazuron
Italian
tidiazuron
Spanish
tidiazuron
Greek
-
Polish
tidiazuron
Swedish
-
Hungarian
-
Dutch
-
Norwegian
-
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