E X T O X N E T
Extension Toxicology Network
A Pesticide Information Project of Cooperative Extension Offices of
Cornell University, Michigan State University, Oregon State University, and
University of California at Davis. Major support and funding was provided
by the USDA/Extension Service/National Agricultural Pesticide Impact
Publication Date: 9/93
TRADE OR OTHER NAMES
Trade names for products containing imazalil include Bromazil,
Deccozil, Fungaflor, Freshgard, and Fungazil. The fungicide is
compatible with many other types of pesticides.
Imazalil is a systemic imidazole fungicide used to control a wide
range of fungi on fruit, vegetables and ornamentals, including powdery
mildew on cucumber and black spot on roses. Imazalil is also used as a
seed dressing and for postharvest treatment of citrus, banana and other
fruit to control storage decay. Under natural conditions it is less
likely that resistant strains of fungi will develop with imazalil than
with some of the other fungicides (4).
Imazalil is a general use pesticide.
Imazalil is classified as a moderately toxic compound and carries
the signal word WARNING on the label. Test animals have experienced
symptoms, including goose flesh (or goose bumps), due to the excitation
of hair folicles, muscle incoordination, reduced arterial tension,
tremors, and vomiting. Contact dermatitis has been noted in some cases
in sensitive individuals.
Imazalil has an oral LD50 of 227 mg/kg for females rat and 343 for
males. The LC50 in dogs is greater than 640 mg/kg (8). The dermal LD50
for rats is 4,200 to 4,880 mg/kg (1) and the inhalation LC50 is greater
than 16 g/m3.
Rats fed imazalil nitrate at dietary levels of 5 to 80 mg/kg for 14
weeks were not affected in appearance, behavior, survival, food
consumption, urinalysis or tissue composition. There were slight liver,
body weight, and bilirubin changes at higher doses (4). Groups of rats
fed 5 to 80 mg/kg for 6, 12, and 24 months did not produce compound or
dose-related effects on body weight gains, food consumption, appearance,
behavior, or survival.
Similar results were found in a dog study where animals received up
to 20 mg/kg for two years. The liver showed some slight effects at the
higher doses, but all other measured and observed parameters were within
In three separate three-generation rat studies at low to moderate
doses (5 to 80 mg/kg), there was a trend to a lower number of live
births at the highest dose level. No differences were noted in percent
of pregnancies or duration of pregnancy (4). It is unlikely that, at
low exposure levels, imazalil will cause reproductive problems.
None of the rat studies mentioned above resulted in fetal
abnormalities. A mouse study at doses up to 40 mg/kg was also negative.
Dominant lethal mutagenic effects were not evident in male and
female mice. It does not appear that imazalil causes serious mutations.
In a group of rats given imazalil for 30 months at low doses (5.0
mg/kg/day), there were no increases in tumors compared to the controls
(4). This suggests that imazalil is non-carcenogenic.
Based on extensive studies of structurally similar human antifungal
drugs, adverse effects on humans are improbable (4).
Fate in Humans and Animals
Imazalil is rapidly absorbed, distributed, metabolized, and
excreted by rats. Following a single dose of imazalil sulfate, 90% was
excreted in 96 hours. Only 3% was the unmetabolized imazalil compound,
indicating almost complete absorption from the gastrointestinal tract.
At least four metabolites are formed. 48 hours after administration,
concentrations in the liver, lung and kidney were higher than 1 mg/kg,
but accumulation in fatty tissue did not occur.
Very little data on ecological effects was found. Both the mallard
duck and the Japanese quail are relatively insensitive to the fungicide.
The LC50 values in these birds range from about 5,500 to 6,300
mg/kg/day. These values indicate that the compound is practically non-
toxic to birds. The compound should not be toxic to bees when used
In sandy or clay soils, the half-life of imazalil was four to five
months. Only 6-7% was metabolized to T824 (D-dealkylated
transformation product) while about 13% was an unidentified, polar
compound. In a plot where seven applications were made at 14-day
intervals, residues were from 0.085 - 0.14 mg/kg in the 0 - 10 cm layer.
Leaching was practically non-existent and accumulation did not appear to
be a problem. Half-life was calculated at about 6.5 months.
In acid to neutral aqueous solutions, imazalil is stable for at
least eight weeks at 40 degrees. Decomposition occurs at elevated
temperatures and under the influence of light (4).
Under normal storage conditions, oranges dipped in 2,000 mg active
ingredient/l and stored have residues (89%) present as the parent
compound. Only a small amount of imazalil was present in the pulp and
part of this may have resulted from handling during peeling (4). The
half-life was 12 to 20 weeks. Studies with apples gave similar results.
One week after treated barley seed was sown in soil, about 76% of
the imazalil was in the adjacent soil and about 29% was in the seedcoat.
After three weeks only 6% was in the green plant parts.
|NOEL: ||2.5 mg/kg/day (dog and rabbit)
|ADI: ||0.03 mg/kg/day (WHO)
|RfD: ||0.013 mg/kg/day (EPA)
|LEL: ||5 mg/kg/day (dog)
|CAS #: ||35554-44-0
|Chemical name: ||1-[2-(2,4-dichlorophenyl)-2-(2-propenyloxy) ethyl}-1H-imidazole
|Chemical class/use: ||imidazole fungicide
|Solubility in water: ||180 mg/l
|Solubility in other solvents: ||hexane 5.21 g/100g; methanol, toluene, benzene >50 g/100g
|Melting Point: ||thermally stable up to 285 degrees C
|Vapor Pressure: ||1.6 x 10-6 mPa at 25 degrees C
Plant Protection Division
40 Kingsbridge Rd
Piscataway, NJ 08855-3998
Review by Basic Manufacturer:
Comments solicited: October, 1992
Comments received: November, 1992
Hartley, D., and H. Kidd, Editors (1991). The Agrochemicals
Handbook. The Royal Society of Chemistry, The University, Nottingham,
Spencer, E.Y. (1981). Guide to the Chemicals Used in Crop
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Worthing, Charles R., Editor (1983). The Pesticide Manual, A World
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Limited, Ravenham, Suffolk, England.
Food and Agriculture Organization of the United Nations, (1977).
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National Institute for Occupational Safety and Health (1983
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Food and Agriculture Organization of the United Nations (1986)
Pesticide Residues in Food - 1986. FAO Plant Production and Protection
Edwards, I Ralph, Donald G. Ferry, and Wayne A. Temple. 1991.
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Volume 3, Classes of Pesticides. Wayland J. Hayes Jr. and Edward R.
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