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Pesticide Information Profiles
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Revised 9/95.
DIMETHOMORPH
TRADE OR OTHER NAMES: Trade names of products containing dimethomorph include Dimethomorphe, Acrobat,
Forum, CME 151, and WL-127294 (1,58).
REGULATORY STATUS: Dimethomorph is not yet registered for use in the United States (58, 306).
INTRODUCTION: Dimethomorph is a systemic fungicide which protects plants from molds, as well as killing molds on
plants and preventing their spread. It is a cinnamic acid derivative and a member of the morpholine chemical family. It is a
mixture of two isomers but only the Z isomer has fungicidal activity (1, 58). Dimethomorph is used as a wood preservative
to control downy mildew on vines, and to control late blight on tomatoes and potatoes (1, 22). The EPA has classified
dimethomorph as Toxicity Class III - slightly toxic. Products containing dimethomorph bear the SIGNAL WORD:
CAUTION (58). It is available as a wettable powder, a dispersible concentrate, and a suspension concentrate (1, 58).
TOXICOLOGICAL EFFECTS
- Acute Toxicity: Dimethomorph is only slightly toxic to mammals. The LD50, the dose which kills half of the test
animals who consume it, is 3900 mg/kg for rats, 5000 mg/kg for male mice, and 3700 mg/kg for female mice (58). The
LD50 for rats whose skin is exposed to dimethomorph is greater than 2000 mg/kg (58, 22). The concentration of
dimethomorph in air which is fatal to half of the animals tested, the LC50, is greater than 4.24 mg/l air for rats.
Dimethomorph is non-irritating to rabbit eyes and skin (1). It is non-sensitizing to guinea pigs' skin (304).
- Chronic Toxicity: No information available
- Reproductive Effects: Studies show that dimethomorph does not cause developmental toxicity (304).
- Teratogenic Effects: No information currently available.
- Mutagenic Effects: Dimethomorph is not mutagenic (304).
- Carcinogenic Effects: Two-year studies on rats and long term studies of mice demonstrate that dimethomorph is
unlikely to cause tumor development (1, 304).
- Organ Toxicity: No information currently available.
- Fate in Humans and Animals: No information currently available.
ECOLOGICAL EFFECTS
- Effects on Birds: Dimethomorph is practically non-toxic to birds. The LD50 is 2000 mg/kg for bobwhite quail and
greater than 2000 mg/kg for mallard ducks (1, 22).
- Effects on Aquatic Organisms: Dimethomorph is moderately toxic to fish. The concentration in water that killed half of
the animals tested, the LC50 (96 hrs), is 6.8 mg/l for rainbow trout, 18 mg/kg for carp and greater than 14 mg/l for
bluegill sunfish. Dimethomorph is slightly toxic to aquatic invertebrates, algae, and bacteria (58,304).
- Effects on Plants: Dimethomorph is non-toxic to most plants (1). However, it is slightly toxic to Eucalyptus at doses of
1.2 mg/ml. A study has also shown that it may affect the cell wall of plants, potentially causing over-production of cell
wall material (305).
- Effects on Other Animals (Nontarget species): Dimethomorph is non-toxic to bees at 0.1 mg/bee, the highest dose
tested (1).
ENVIRONMENTAL FATE
- Breakdown of Chemical in Soil and Groundwater: Dimethomorph has a low soil mobility and low leaching
potential(304).
- Breakdown of Chemical in Surface Water: No information currently available.
- Breakdown of Chemical in Vegetation: Dimethomorph is only metabolized to a small degree in plants. In studies of
crops at harvest, either no residues or residues up to 0.5 mg/kg were found (1).
PHYSICAL PROPERTIES AND GUIDELINES
Physical Properties:
- Appearance: Dimethomorph is a colorless or grey crystalline powder that is stable under normal temperature conditions.
- Chemical Name: 4-[3-(4-chlorophenyl)-3-(3,4-dimethoxyphenyl)-1-oxo-2-propenyl]morpholine (1)
- CAS Number: 110488-70-5
- Molecular Weight: 387.9
- Water Solubility: greater than 50 mg/l at 20-23 degrees C(1)
- Solubility in Other Solvents: Soluble in acetone, toluene, hexane, and methanol (1)
- Melting Point: 125-149 degrees C (58)
- Vapor Pressure: 9.7 x 10-4 mPa
- Partition Coefficient: Not Available
- Adsorption Coefficient: Not Available
Exposure Guidelines:
- ADI: 0.1 mg/kg body weight (304)
- MCL: Not Available
- RfD: Not Available
- PEL: Not Available
- HA: Not Available
- TLV: Not Available
BASIC MANUFACTURER:
American Cyanamid Company
One Cyanamid Plaza
Wayne, NJ 07470
- Telephone: 201-831-2000
- Emergency: 201-835-3100
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 label/ing or other regulatory requirements. Please refer to the pesticide product label/ing.