| thidiazuron (Ref: SN 49537) |
 |
Environmental Fate - Ecotoxicology - Human Health - A to Z Index - Home
GENERAL INFORMATION 
for thidiazuron
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
EC Regulation 1107/2009 (repealing 91/414):
| Status | Not approved |
| Dossier rapporteur/co-rapporteur | Not applicable |
| Date inclusion expires | Expired |
| EU Candidate for substitution (CfS) | Not applicable |
| 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 |
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Also used in: Australia, USA
Chemical structure:
| Isomerism | - |
| Chemical formula | C9H8N4OS |
| Canonical SMILES | C1=CC=C(C=C1)NC(=O)NC2=CN=NS2 |
| Isomeric SMILES | No data |
| 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 group | Phenylurea | |||
| Minimum active substance purity | - | |||
| Known relevant impurities | - | |||
| Substance origin | Synthetic | |||
| Mode of action | Absorbed by leaves. A cytokine-active growth regulator. Inhibition of protoporphyrinogen oxidase (PPO). | |||
| CAS RN | 51707-55-2 | |||
| EC number | 257-356-7 | |||
| CIPAC number | 727 | |||
| US EPA chemical code | 120301 | |||
| PubChem CID | 40087 | |||
| Molecular mass (g mol-1) | 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 | Colourless crystals | |||
| Related substances & organisms | ||||
Formulations:
| Property |
Value | |||
| Example manufacturers & suppliers of products using this active now or historically |
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| Example products using this active |
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| UK LERAP status | No UK approval for use as a pesticide under EC Regulation 1107/2009 | |||
| Formulation and application details | Usually supplied as wettable powders and emulsifiable concentrates. | |||
ENVIRONMENTAL FATE
for thidiazuron
| Property |
Value | Source/Quality Score/Other Information |
Interpretation |
|
| Solubility - In water at 20oC (mg l-1) | 20 | H4 | Low | |
| Solubility - In organic solvents at 20oC (mg l-1) | 2 | L3 - Hexane | - | |
| 4200 | L3 - Methanol | - | ||
| 3 | L3 - Dichloromethane | - | ||
| 400 | L3 - Toluene | - | ||
| Melting point (oC) | 211.5 | L3 | - | |
| Boiling point (oC) | - | - | - | |
| Degradation point (oC) | - | - | - | |
| Flashpoint (oC) | - | - | - | |
| Octanol-water partition coefficient at pH 7, 20oC | P | 5.89 X 1001 | Calculated | - |
| Log P | 1.77 | V3 | Low | |
| Bulk density (g ml-1)/Specific gravity | 1.51 | Q2 | - | |
| Dissociation constant (pKa) at 25oC | 8.86 | L3 | - | |
| Note: Weak acid | ||||
| Vapour pressure at 20oC (mPa) | 3.00 X 10-06 | H4 | Low volatility | |
| Henry's law constant at 25oC (Pa m3 mol-1) | 3.30 X 10-08 | H4 | Non-volatile | |
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 |
- | Calculated | Medium | |
| Maximum UV-vis absorption L mol-1 cm-1 | - | - | - | |
| Surface tension (mN m-1) | - | - | - | |
Degradation:
| Property |
Value | Source/Quality Score/Other Information |
Interpretation |
General biodegradability | - |
| Soil degradation (days) (aerobic) | DT50 (typical) | 85 | H4 | Moderately persistent |
| DT50 (lab at 20oC) | 10 | F3 | Non-persistent | |
| DT50 (field) | - | - | - | |
| DT90 (lab at 20oC) | - | - | - | |
| 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 | - |
| Note | Cotton leaves, n=1 | |||
| Aqueous photolysis DT50 (days) at pH 7 | Value | - | - | - |
| Note | - | |||
| Aqueous hydrolysis DT50 (days) at 20oC and pH 7 | Value | - | - | - |
| Note | - | |||
| Water-sediment DT50 (days) | - | - | - | |
| Water phase only DT50 (days) | - | - | - | |
Soil adsorption and mobility:
| Property |
Value | Source/Quality Score/Other Information |
Interpretation |
|
| Linear | Kd | - | H3 | Slightly mobile |
| Koc | 742 | |||
| Notes and range | Other sources: 110 mL/g (DW4) | |||
| Freundlich | Kf | - | - | - |
| Kfoc | - | |||
| 1/n | - | |||
| Notes and range | - | |||
| pH sensitivity | - | |||
| Property |
Value | Source/Quality Score/Other Information |
Interpretation |
|
| Bio-concentration factor | BCF (l kg-1) | 6.2 | Q2 Estimated | Low potential |
| CT50 (days) | Not available | - | ||
| Mammals - Acute oral LD50 (mg kg-1) | > 5350 | V3 Rat | Low | |
| Mammals - Short term dietary NOEL | (mg kg-1) | - | Z2 Rat | - |
| (ppm diet) | > 200 | - | ||
| Birds - Acute LD50 (mg kg-1) | > 16000 | V3 Phasianidae | Low | |
| Birds - Short term dietary (LC50/LD50) | - | - | - | |
| Fish - Acute 96 hour LC50 (mg l-1) | > 19 | F4 Oncorhynchus mykiss | Moderate | |
| Fish - Chronic 21 day NOEC (mg l-1) | 5.7 | P3 Pimephales promelas | Moderate | |
| Aquatic invertebrates - Acute 48 hour EC50 (mg l-1) | > 10 | J4 Daphnia magna | Moderate | |
| Aquatic invertebrates - Chronic 21 day NOEC (mg l-1) | 0.1 | F3 Daphnia magna, LOEC | Moderate | |
| Aquatic crustaceans - Acute 96 hour LC50 (mg l-1) | 2.8 | F3 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 Lemna gibba, 7 day | Low | |
| Non-target plants | - | - | - | |
| - | - | - | ||
| Algae - Acute 72 hour EC50, growth (mg l-1) | 0.15 | F2 Pseudokirchneriella subcapitata | Moderate | |
| 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) | - | - | - |
| 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 | Low | |
| 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
for thidiazuron
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) | > 5350 | V3 Rat | Low | |
| Mammals - Dermal LD50 (mg kg-1 body weight) | > 1000 | L3 Rat | - | |
| Mammals - Inhalation LC50 (mg l-1) | 2.3 | L3 Rat, 4 hr | - | |
| Other Mammal toxicity endpoints | - | - | ||
| ADI - Acceptable Daily Intake (mg kg-1bw day-1) | - | - | - | |
| ARfD - Acute Reference Dose (mg kg-1bw day-1) | - | - | - | |
| AAOEL - Acute Acceptable Operator Exposure Level (mg kg-1 bw day-1) | - | - | - | |
| AOEL - Acceptable Operator Exposure Level - Systemic (mg kg-1bw day-1) | - | - | - | |
| Dermal penetration studies (%) | - | - | - | |
| Dangerous Substances Directive 76/464 | - | - | - | |
| Exposure Routes | Public | - | ||
| Occupational | - | |||
| European MRLs | Click here for the EU MRL pesticide database | |||
| Drinking Water Standards | - | - | - | |
| Drinking Water MAC (μg l-1) | - | - | - | |
Health issues:
| Carcinogen | Genotoxic | Endocrine disrupter | Reproduction / development effects | Cholinesterase inhibitor | Neurotoxicant | |||
|
A0; B0; C0; D0; E0 | - |
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| Respiratory tract irritant | Skin irritant | Skin sensitiser | Eye irritant | Phototoxicant | ||||
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| General human health issues | No further information available | |||||||
| Key: Genotoxicity A: Chromosome aberration (EFSA database) B: DNA damage/repair (EFSA database) C: Gene mutation (EFSA database) D: Genome mutation (EFSA database) E: Unspecified genotoxicity type (miscellaneous data source) 0: No data 1: Positive 2: Mixed/ambiguous results 3: Negative |
Key: Other : Yes, known to cause a problem  : No, known not to cause a problem  : Possibly, status not identified - : No data found |
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Handling issues:
| Property |
Value | Source/Quality Score/Other Information |
Interpretation |
|
| General |
Incompatible with strong oxidizing agents | |||
| CLP classification 2013 | Health: H312, H315, H319, H332, H335 | |||
| EC Risk Classification |
Xi - Irritant: S36/37/38 | |||
| EC Safety Classification |
S22, S26, S36 | |||
| WHO Classification | III | - | Slightly hazardous | |
| UN Number | - | |||
| Waste disposal & packaging |
- | |||
| Language | Name |
| English | thidiazuron |
| French | thidiazuron |
| German | Thidiazuron |
| Danish | thidiazuron |
| Italian | tidiazuron |
| Spanish | tidiazuron |
| Greek | - |
| Slovenian | tidiazuron |
| Polish | tidiazuron |
| Swedish | - |
| Hungarian | - |
| Dutch | - |
Record last updated: Wednesday 27 November 2019
Contact: aeru@herts.ac.uk