diphenamid (Dymid, Enide) Herbicide Profile 2/85
CHEMICAL NAME: N,N-Dimethyl-2,2-diphenylacetamide (56)
TRADE NAME(S): Dymid, Enide (56)
FORMULATION(S): Available in 50 and 80% wettable powders; 4
pounds/gallon liquid dispersion, and 5% granules
TYPE: Selective preemergence herbicide
BASIC PRODUCER(S): TUCO, Div. of the Upjohn Co.
Kalamazoo, MI 49001
STATUS: General use
PRINCIPAL USES: For control of annual grasses and broadleaf weeds
in peanuts, tobacco seedbeds, field tobacco, tomatoes and peppers,
okra, Irish potatoes, sweet potatoes, cotton, soybeans, strawberries,
blackberry and raspberry (nonbearing), apple and peach trees, orange,
lime and cherry trees (nonbearing), pine seedbeds, dichondra, iceplant,
bermudagrass lawns and other ornamental plants (56).
Combined with DNBP for usage on peanuts, potatoes and soybeans (8b).
APPLICATION METHOD(S): Diphenamid is a preemergence surface-applied
herbicide. Light rainfall or sprinkler irrigation following diphenamid
application will improve its control of weeds. Under conditions of
dry weather following application of diphenamid, soil incorporation may
increase the efficacy of the herbicide. Diphenamid may be applied
immediately after seeding the crop or over top of transplant crops any
time after transplanting but prior to weed emergence (58).
Enide 90W for control of the following weeds:
Annual bluegrass Goosegrass (Crowfoot grass)
Annual sedge Johnsongrass (from seed)
Barnyardgrass (watercress) Ryegrass
Cheat Sandbur (Sandspur)
Fall panicum (Panic grass) Wild Oat
Foxtail Witchgrass (Ticklegrass)
Carpetweed Mouseear chickweed
Common chickweed Pigweed (Careless weed)
Corn spurry Purslane
Evening primrose Red sorrel
Field pepperweed Shepherdspurse
Florida pusley Smartweed
Groundsel Spiny amaranth (Stickerweed)
Knotgrass (German moss) Thymeleaf
Germinated weeds are not controlled. Important tolerant weeds
include buffaloburr, ground cherry, horsenettle, Jimsonweeed, nightshade,
velvetleaf, nutgrass, and established annual and perennial weeds. Highly
susceptible crop plants include barley, carrots, corn, millets, red
beets, rye, sorghum, spinach, sugar beets, Swisschard, and wheat.
No contact activity. Weed control of 6-8 months duration can be
expected. Fall applications of 6 lbs./acre or more have greatly
suppressed the growth of quackgrass. Continued application should not
result in a buildup in the soil (8b).
II. PHYSICAL PROPERTIES
MOLECULAR FORMULA: C16 H17 N O (62)
MOLECULAR WEIGHT: 239.3 (62)
PHYSICAL STATE: Colorless crystals (pure compound); off-white
solid (technical product) (62).
ODOR: No appreciable odor (pure compound) (58).
MELTING POINT: 134.5 - 135.5 C (pure compound); 132-134 C
(technical product) (62).
VAPOR PRESSURE: Negligible at room temperature (pure compound) (62)
SOLUBILITY: 260 mg/l water at 27 C (pure compound) (62)
III. HEALTH HAZARD INFORMATION
OSHA STANDARD: NA
NIOSH RECOMMENDED LIMIT: NA
ACGIH RECOMMENDED LIMIT: NA
A. ACUTE TOXICITY
DERMAL: LD50 = >225 mg/kg (rat) (62)
No toxicity from application of 6.320 mg/kg to skin
of rabbits. No irritation from daily application of dry powder or 0.1%
water suspension to abraded or unabraded skin of rabbits for 5 days.
Guinea pigs were not sensitized to intradermal injections of a 0.1%
diphenamid suspension (58).
ORAL: LD50 = 1050 mg/kg (rat) (62)
LD50 (estimated) = 590 mg/kg (mouse), 970 plus or minus
140 mg/kg (rat, adult), 270 plus or minus 20 mg/kg (rat, weanling), 290
plus or minus 40 mg/kg (rat, newborn), 1500 mg/kg (rabbit), 1000 mg/kg
(dog, male), >1000 mg/kg (dog, female), >1000 mg/kg (monkey, male),
>1000 mg/kg (monkey, female) (Dymid, 80% a.i.) (58).
LD50 (estimated) = 1717 mg/kg (mouse), 1373 mg/kg (rat,
adult) (Diphenamid) (58).
INHALATION: No toxicity to rats exposed 1 hour at 0.9
EYES: No eye irritation occurred in rabbits from a dry powder
or a 0.1% water suspension applied to the conjunctival
B. SUBACUTE AND CHRONIC TOXICITY:
In 2-year feeding trials dogs and rats receiving 2000 mg/kg diet
suffered no unusual effect on their physiology or fertility (62).
Diphenamid was not toxic when administered for 90 days to rats at
30 mg/kg or to dogs at 10 mg/kg (58).
Safe feeding level, 2 years: rats - 100 ppm in diet; dogs - 250
ppm, in capsule administered daily (58).
IV. ENVIRONMENTAL CONSIDERATIONS
General Toxicity to Wildlife and Fish: Low (58).
Behavior In or On Soils
1. Adsorption and leaching characteristics in basic soil types:
Diphenamid is not tightly adsorbed on soil colloids. It leaches
rapidly in sandy soils but slowly in loam or clay soils. In sandy
soils, retention of an effective concentration in the weed seed
germination zone with heavy rainfall can be a problem.
2. Microbial breakdown: Microorganisms appear to play a significant
role in degradation of diphenamid in soil. Certain species of soil
fungi are capable of metabolizing diphenamid in vitro.
3. Loss from photodecomposition and/or volatilization: Diphenamid is
nonvolatile and appears to be relatively stable in sunlight.
4. Resultant average persistence at recommended rates: Long lasting
weed control can be expected from recommended rates of diphenamid.
Under warm, moist conditions the average persistence at herbicidal
levels is from 3 to 6 months. Under low rainfall conditions,
diphenamid may be persistent in soil (58).
V. EMERGENCY AND FIRST AID PROCEDURES
The chemical information provided below has been condensed
from original source documents, primarily from "Recognition and
Management of Pesticide Poisonings", 3rd ed. by Donald P. Morgan,
which have been footnoted. This information has been provided in
this form for your convenience and general guidance only. In
specific cases, further consultation and reference may be required
and is recommended. This information is not intended as a sub-
stitute for a more exhaustive review of the literature nor for the
judgement of a physician or other trained professional.
If poisoning is suspected, do not wait for symptoms to develop.
Contact a physician, the nearest hospital, or the nearest Poison
SYMPTOMS OF POISONING: Compound is an emetic to dogs and monkeys.
Assumed to cause similar effects in man. May induce convulsions (58).
INGESTION: Induction of vomiting and supportive treatment (58).
VI. FIRE AND EXPLOSION INFORMATION
Compatible with most other wettable powder herbicidal formulations
and fertilizers, if not highly alkaline. Diphenamid wettable powder is
not significantly influenced in its sprayability by water hardness.
Diphenamid is not corrosive (58).
VIII. PROTECTIVE MEASURES
STORAGE AND HANDLING: Harmful if swallowed. Avoid prolonged or
repeated contact with skin. Do not use cover crops for food or feed
within 6 months after application. Avoid breathing dust. Avoid
contamination of feed or foodstuffs. Keep out of lakes, streams, and
ponds. Do not contaminate water by cleaning of equipment or disposal
of wastes or containers. Do not contaminate water, food, or feed by
storage or disposal (50b).
IX. PROCEDURES FOR SPILLS AND LEAKS
IN CASE OF EMERGENCY, CALL, DAY OR NIGHT
PESTICIDE TEAM SAFETY NETWORK/CHEMTREC
X. LITERATURE CITED
8b. Thomson, W.T. 1981. Agricultural chemicals - book 2:
herbicides. Revised ed. Thomson Publications, Fresno, CA.
50b. TUCO, Division of the Upjohn Co. 1981. Specimen label: Enide 90W.
56. Farm Chemicals Handbook, 70th ed. 1984. R. T. Meister, G. L.
Berg, C. Sine, S. Meister, and J. Poplyk, eds. Meister
Publishing Co., Willoughby, OH.
58. Weed Science Society of America, Herbicide Handbook Committee.
1983. Herbicide handbook of the weed science society of
America, 5th ed. Weed Science Society of America, Champaign,
IL. 515 pp.
62. The Pesticide Manual: A World Compendium, 7th ed. 1983. C.R.
Worthing, ed. The British Crop Protection Council, Croydon,
England. 695 pp.