Diquat dibromide is a contact desiccant and herbicide. It is highly soluble in water, has a low risk of leaching to groundwater and is volatile. It is very persistent in soil but rapidly degrades in aquatic systems. It is moderately toxic to mammals and is a known irritant but no other significant human health issues have been identified. It is moderately toxic to birds, most aquatic organisms, honeybees and earthworms.
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 High alert: Very persistent
Warning: Significant data are missing
Human health Moderate alert: Mammals acute toxicity: Moderate
GENERAL INFORMATION
Description
A non-residual bupyridyl herbicide and crop desiccant used mainly to control broad-leaved weeds and grasses
Example pests controlled
Water lettuce; Water hyacynth; Duckweed; Pennywort; Annual bluegrass; Fescue; Henbit; Buttercup
Example applications
Potatoes; Oilseed rape; Fruit including apples, pears, peaches, plums, citrus, olive, grapes; Tomatoes; Sunflowers; Vegetables including beans & peas, carrots, onions, chicory; Sugarbeet
Efficacy & activity
-
Availability status
Current
Introduction & key dates
1958, first reported
GB regulatory status
GB COPR regulatory status
Not approved
Date COPR inclusion expires
Expired
GB LERAP status
No UK approval for use as a pesticide
EC Regulation 1107/2009 (repealing 91/414)
EC Regulation 1107/2009 status
Not approved
Dossier rapporteur/co-rapporteur
UK/Sweden
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
Example manufacturers & suppliers of products using this active now or historically
AgriGuard
Clayton
Standon
Syngenta
ICI Plant Protection
Example products using this active
Reglone
Retro
Quad
Googly
Weedol
Reglox
Formulation and application details
Often supplied as a soluble concentrate, gel or liquid concentrate
ENVIRONMENTAL FATE
Property
Value
Source; quality score; and other information
Interpretation
Solubility - In water at 20 °C (mg l⁻¹)
-
-
-
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
-
-
-
Log P
-
-
-
Fat solubility of residues
Solubility
-
-
-
Data type
-
-
-
Density (g ml⁻¹)
-
-
-
Dissociation constant pKa) at 25 °C
Not applicable
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
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
Stable
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
Stable
Note
Stable pH 5 to pH 9
Water-sediment DT₅₀ (days)
-
-
-
Water 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
-
Fate indices
Property
Value
Source; quality score; and other information
Interpretation
GUS leaching potential index
-
-
-
SCI-GROW groundwater index (μg l⁻¹) for a 1 kg ha⁻¹ or 1 l ha⁻¹ application rate
Value
Cannot be calculated
-
-
Note
-
Potential for particle bound transport index
-
-
-
Potential for loss via drain flow
-
-
-
Photochemical oxidative DT₅₀ (hrs) as indicator of long-range air transport risk
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
Rat
Moderate
Mammals - Short term dietary NOEL
(mg kg⁻¹)
-
-
-
(ppm diet)
-
-
Mammals - Chronic 21d NOAEL (mg kg⁻¹ bw d⁻¹)
-
-
-
Birds - Acute LD₅₀ (mg kg⁻¹)
-
-
-
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)
-
-
-
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
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)
Aquatic plants - Acute 7 day EC₅₀, biomass (mg l⁻¹)
-
-
-
Algae - Acute 72 hour EC₅₀, growth (mg l⁻¹)
-
-
-
Algae - Chronic 96 hour NOEC, growth (mg l⁻¹)
-
-
-
Mesocosm study data
NOEAEC mg l⁻¹
-
-
-
NOEAEC mg l⁻¹
-
-
-
Marine bivalves
-
-
-
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)
1000
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
Rat
Moderate
Mammals - Dermal LD₅₀ (mg kg⁻¹ body weight)
2000
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
Rat
-
Mammals - Inhalation LC₅₀ (mg l⁻¹)
> 0.5
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
A3 A = Chromosome aberration (EFSA database) 3 = Negative
;
B3 B = DNA damage/repair (EFSA database) 3 = Negative
;
C3 C = Gene mutation (EFSA database) 3 = Negative
;
D0 D = Genome mutation (EFSA database) 0 = No data
;
E3 E = Unspecified genotoxicity type (miscellaneous data source) 3 = Negative
XNo, known not to cause a problem
Reproduction / development effects
Acetyl cholinesterase inhibitor
Neurotoxicant
XNo, known not to cause a problem
XNo, known not to cause a problem
XNo, known not to cause a problem
Respiratory tract irritant
Skin irritant
Skin sensitiser
✓Yes, known to cause a problem
✓Yes, known to cause a problem
✓Yes, known to cause a problem
Eye irritant
Phototoxicant
✓Yes, known to cause a problem
No data found
General human health issues
Potential liver, kidney, stomach and intestine toxicant Fatal if inhaled
Handling issues
Property
Value and interpretation
General
IMDG Transport Hazard Class 6.1 Corrosive to most metals & may form flammable and explosive H2 gas when in contact with aluminum May decompose at high temperatures to form toxic gases
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
Environmental fate
Warning:
Human health
