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The information in this profile may be out-of-date. It was last revised in 1996. EXTOXNET no longer updates this information, but it may be useful as a reference or resource.

Please visit the National Pesticide Information Center (NPIC) to find updated pesticide fact sheets. If you don't find a fact sheet related to your question, feel free to call 1-800-858-7378. NPIC is open five days a week from 8:00am to 12:00pm Pacific Time.

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E X T O X N E T

Extension Toxicology Network

Pesticide Information Profiles

A Pesticide Information Project of Cooperative Extension Offices of Cornell University, Oregon State University, the University of Idaho, and the University of California at Davis and the Institute for Environmental Toxicology, Michigan State University. Major support and funding was provided by the USDA/Extension Service/National Agricultural Pesticide Impact Assessment Program.

EXTOXNET primary files maintained and archived at Oregon State University

Revised June 1996

Imazalil

Trade and 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.

Regulatory Status: Imazalil is a moderately toxic compound in EPA toxicity class II. Labels for products containing it must bear the Signal Word WARNING [1]. Imazalil is a General Use Pesticide (GUP).

Chemical Class: imidazole

Introduction: 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 imazalil treatment will lead to resistant strains of fungi than as a result of treatment with other fungicides.

Formulation: Not Available

Toxicological Effects:

• Acute toxicity: Imazalil is moderately toxic by ingestion, with a reported oral LD50 of 227 to 343 mg/kg in rats [1,8]. The LD50 in dogs is greater than 640 mg/kg [41]. The reported dermal LD50 is 4200 to 4880 mg/kg in rats, indicating slight toxicity [1]. Test animals have experienced symptoms such as excitation of hair folicles (goose pimples), muscle incoordination, reduced arterial tension, tremors, and vomiting [41]. Contact dermatitis has been noted in some cases in sensitive individuals [41].
• Chronic toxicity: Rats fed imazalil nitrate at dietary levels of up to 0.4 mg/kg/day 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 [41]. Groups of rats fed up to 0.4 mg/kg/day for 6, 12, and 24 months did not show compound or dose related effects on body weight gain, food consumption, appearance, behavior, or survival [41]. Similar results were found in a dog study where animals received up to 0.5 mg/kg/day for 2 years. The liver showed some slight effects at the higher doses, but all other measured and observed parameters were within normal limits [41].
• Reproductive effects: In three separate three-generation rat studies at low to moderate doses of 0.4 mg/kg/day, 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 [3,41]. These data suggest that imazalil is unlikely to cause reproductive effects under normal conditions.
• Teratogenic effects: None of the rat studies mentioned above resulted in fetal abnormalities. A mouse study at doses up to 4.8 mg/kg/day was also negative. It is unlikely that imazalil is teratogenic [3,41].
• Mutagenic effects: Dominant lethal mutagenic effects were not evident in male and female mice [3]. Based on these data, it appears that imazalil is not mutagenic.
• Carcinogenic effects: In a group of rats given imazalil for 30 months at a dose of 5.0 mg/kg/day, there were no increases in tumors compared to the controls [41]. This suggests that imazalil is noncarcinogenic.
• Organ toxicity: Based on animal tests, imazalil affects the nervous system and liver.

• 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 metabolized form within 96 hours [1]. Only 3% was eliminated via the feces in nonmetabolized form, indicating almost complete absorption from the gastrointestinal tract [41]. At least four metabolites are formed 48 hours after administration. Accumulation in fatty tissue did not occur [41].

Ecological Effects:

• Effects on birds: Both the mallard duck and the Japanese quail are relatively insensitive to the fungicide. The 8-day LC50 values in these birds range from about 5500 to 6300 mg/kg/day [1]. These values indicate that the compound is practically nontoxic to birds.
• Effects on aquatic organisms: Imazalil is moderately toxic to fish. The LC50 for imazalil in trout is 2.5 mg/L and in the bluegill sunfish is 3.2 mg/L [1].
• Effects on other organisms: The compound is non-toxic to bees [1].

Environmental Fate:

• Breakdown in soil and groundwater: Imazalil is highly persistent in the soil environment, with a reported field half-life of between 120 and 190 days [11]. A representative value is estimated to be 150 days for most soils [11]. It is soluble in water, but strongly bound to soils [11], and thus unlikely to pose a risk to groundwater. In a plot where seven applications were made at 14-day intervals, leaching was practically nonexistent and accumulation did not appear to be a problem [42].
• Breakdown in water: In acid to neutral aqueous solutions, imazalil is stable for at least 8 weeks at 40 F. Decomposition occurs at elevated temperatures and under the influence of light [41].
• Breakdown in vegetation: 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 3 weeks, only 6% was in the green plant parts. Under normal storage conditions, oranges dipped in 2000 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 [41]. Studies with apples gave similar results.

Physical Properties:

• Appearance: Imazalil is a slightly yellow to brown solidified oil [1].
• Chemical Name: (+/-)-allyl 1-(2,4-dichlorophenyl)-2-imidazol-1-ylether ester [1]
• CAS Number: 35554-44-0
• Molecular Weight: 297.18
• Water Solubility: 1400 mg/L @ 20 C [1]
• Solubility in Other Solvents: s.s. in hexane, methanol, toluene, benzene [1]
• Melting Point: 50 C [1]
• Vapor Pressure: 0.0093 mPa 25 C [1]
• Partition Coefficient: 3.8195 [1]
• Adsorption Coefficient: 4000 [1]

Exposure Guidelines:

• ADI: 0.03 mg/kg/day [12]
• MCL: Not Available
• RfD: 0.013 mg/kg/day [13]
• PEL: Not Available
• HA: Not Available
• TLV: Not Available

Basic Manufacturer:

Janssen Pharmaceutica
Plant Protection Division
1125 Trenton-Harbourton Road
Titusville, NJ 08560-1200

• Phone: 609-730-2607
• Emergency: Not Available
  

References:

References for the information in this PIP can be found in Reference List Number 10

DISCLAIMER: The information in this profile does not in any way replace or supersede the information on the pesticide product labeling or other regulatory requirements. Please refer to the pesticide product labeling.