tebuthiuron (Graslan, Spike) Herbicide Profile 2/85
CHEMICAL NAME: N-[5-(1,1-dimethylethyl)-1,3,4-thiadiazol-z-yl]-
TRADE NAME(S): Graslan, Spike (56)
FORMULATION(S): Spike: Wettable powder 80%, 20% pellet, 5%
granule, 1% granule. Graslan offered as 10%
pellet, 10% pellet (56).
TYPE: Urea derivative herbicide
BASIC PRODUCER(S): Elanco Products Co.
Div. of Eli Lilly and Co.
740 South Alabama St.
Indianapolis, IN 46285
STATUS: General use
PRINCIPAL USES: Graslan is used for brush and weed control in
rangeland. Spike is used on noncropland areas for control of grasses,
broadleaf weeds and woody plants (58).
APPLICATION METHOD(S): Tebuthiuron is sprayed or spred dry (as granules
or pellets) on the soil surface, preferably just before or during the
period of active growth of weeds. Initial control is enhanced by
Spike controls many species of grasses, broadleaf weeds, and woody
plants (63a). For a complete listing of species controlled, contact
the Chemicals-Pesticides Program, Department of Entomology, Cornell
Spike does not control the following weeds:
Bindweed, field (Convolvulus arvensis)
Cucumber, western wild (Echinocystis oregona)
Dogbane, hemp (Apocynum cannabinum)
Dropseed, prairie (Sporobolus heterolepis)
Johnsongrass [rhizome] (Sorghum halepense)
Milkweed, climbing (Sarcostemma cyanchoides)
Nutsedge (Cyperus spp.)
Redvine (Brunnichia cirrhosa) (63a).
Important Weeds Controlled: Alfalfa, bluegrasses, bromes, bouncingbet,
butter cups, chickweed, clovers, cocklebur, dock, fescue, fiddleneck,
filaree, foxtails, goldenrod, henbit, horseweed, kochia, lambsquarters,
morning glory, mullein, nightshade, wild oats, pigweed, puncture vine,
ryegrass, prickley sida, sowthistle, spurge, sunflower, Russian thistle,
vetch, witchgrass, woody plants and many others (8b).
Woody plants take a period of 2-3 years to be completely controlled
II. PHYSICAL PROPERTIES
MOLECULAR FORMULA: C9 H16 N4 O5 (58)
MOLECULAR WEIGHT: 228.3 (58)
PHYSICAL STATE: Colorless solid (technical product) (62)
ODOR: Odorless (58)
MELTING POINT: 161.5-164 C (technical product) (62)
VAPOR PRESSURE: 2 x 10+6 mmHg at 25 C (58)
SOLUBILITY: 2.5 g/l water at 25 C (technical product) (62)
III. HEALTH HAZARD INFORMATION
OSHA STANDARD: NA
NIOSH RECOMMENDED LIMIT: NA
ACGIH RECOMMENDED LIMIT: NA
A. ACUTE TOXICITY
DERMAL: 200 mg/kg produced no dermal irritation (rabbit) (58)
ORAL: LD50 = 579 plus or minus 11 mg/kg (mouse); 644 plus or
minus 27 mg/kg (rat); 286 plus or minus 30 mg/kg
(rabbit); LD0 >500
mg/kg (dog no animals died at this dosage); LD0 >200
mg/kg (cat, no animals died at this dosage) (58).
INHALATION: 80 W formulation produced no deaths or toxicity
of concentrations of 2.12 g/m3 of inhaled air for 1
EYES: 71 mg/eye produced no irritation to cornea or iris,
transient inflammation of conjunctiva (rabbit) (58).
B. SUBACUTE AND CHRONIC TOXICITY:
Safe levels after 3 months of feeding: rats - 1000 ppm, dogs -
1000 ppm, and 1 month feeding in chickens - 1000 ppm (58).
No harm observed due to feeding tebuthiuron to rats for three
generations. No evidence of teratogenicity in rats or rabbits.
Tebuthiuron was negative in the dominant lethal test (58).
In 2-year feeding trials rats and mice receiving 1600 mg/kg diet
suffered no ill-effect (62).
IV. ENVIRONMENTAL CONSIDERATIONS
General toxicity to wildlife and fish: Rat, rabbit, dog, mallard,
and fish rapidly absorb, metabolize, and excrete tebuthiuron
through the kidneys. There is no major binding of tebuthiuron or its
metabolites in animal tissues.
Morton, D.M. and D.G. Hoffman. Metabolism of new herbicide
-urea) in mouse, rat, rabbit, dog, duck, and fish. J. Toxicol.
Environ. Health 1:757-768. 1976 (58).
Chicken, quail, duck: LD0 >500 mg/kg (no deaths at this dosage)
Trout: TL50 144 ppm
Bluegill: TL50 112 ppm
Eastern oyster: EC50 >180 <320 ppm
Fiddler crab: LC50 >320 ppm
Pink shrimp: LD50 >48 ppm (58)
LC50 (96-hr) >160 mg/l for goldfish and fathead minnow (62)
Behavior In Or On Soils
1. Adsorption and leaching characteristics: Tebuthiuron has a half
life in soil of 12 to 15 months in areas receiving 40 to 60
inches annual rainfall. The half life is considerably
greater in low rainfall areas and in muck and other high
organic soils regardless of rainfall. In field studies,
tebuthiuron and its transformation products have seldom been
detected below the top 12 inches of soil. Little or no
lateral movement has been observed.
Chang, S.S. and J.F. Strizke. Sorption, movement, and dissipation
of tebuthiuron in soils. Weed Sci. 25:184-187, 1977.
2. Microbial breakdown: Microbial breakdown has been shown to occur.
However, the predominant mode of degradation probably does
not involve soil microbes.
3. Loss from photodecomposition and/or volatilization: Tests
indicate that loss from soil due to photodecomposition and
volatiization is negligible (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 substitute
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
KNOWN OR SUSPECTED ADVERSE EFFECTS: Many substituted ureas are
moderately irritating to skin, eyes, and mucous membranes (25).
SKIN CONTACT: Wash contaminated skin with soap and water (25).
INGESTION: Ingestions of small amounts (less than 10 mg/kg body
weight) occurring less than an hour before treatment, are probably best
A. Syrup of Ipecac, followed by 1-2 glasses of water. Dose for
adults and children over 12 years: 30 ml. Dose for children
under 12 years: 15 ml.
B. Activated Charcoal - Administer 30-50 gm as a slurry in tap water,
after vomiting stops.
C. Sodium or Magnesium Sulfate, 0.25 gm/kg in tap water, as a
EYE CONTACT: Flush contaminated eyes with copious amount of fresh
water for 15 minutes (25).
NOTES TO PHYSICIAN:
1. INGESTIONS of LARGE amounts (more than 10 mg/kg) occurring less
than an hour before treatment, should probably be treated by
A. INTUBATE stomach and ASPIRATE contents.
B. LAVAGE stomach with slurry of ACTIVATED CHARCOAL in 0.9%
saline. Leave 30-50 gm activated charcoal in the stomach
before withdrawing tube.
C. SODIUM SULFATE, 0.25 gm/kg in tap water, as a cathartic.
CAUTION: Hydrocarbons (kerosene, petroleum distillate) are
included in some formulations of these chemicals.
Ingestion of very LARGE AMOUNTS may cause CNS
depression. In this case, IPECAC IS
CONTRAINDICATED. Also, gastric intubation incurs
a risk of HYDROCARBON PNEUMONITIS. For this
reason observe the following precautions:
(1) If the victim is unconscious or obtunded and
facilities are at hand, insert an
ENDOTRACHEAL TUBE (cuffed, if available)
prior to gastric intubation.
(2) Keep victim's HEAD BELOW LEVEL OF STOMACH
during intubation and lavage (Trendelenburg,
or left lateral decubitus, with head of table
tipped downward). Keep victim's head turned
to the left.
(3) ASPIRATE PHARYNX as regularly as possible to
remove gagged or vomited stomach contents.
2. INGESTIONS occurring MORE THAN an HOUR before treatment are
probably best treated only by ACTIVATED CHARCOAL, 30-50 gm, and
SODIUM or MAGNESIUM SULFATE, 0.25 gm/kg, as described above.
3. There are no specific antidotes for these chemicals. Because
manifestations of toxicity do occasionally occur in peculiarly
predisposed individuals, MAINTAIN CONTACT with victim for at least
72 hours so that unexpected adverse effects can be treated
VI. FIRE AND EXPLOSION INFORMATION
Not flammable (58).
Compatible with other herbicides tested. Noncorrosive (58).
VIII. PROTECTIVE MEASURES
STORAGE AND HANDLING: Storage stability: Stable. Harmful if
swallowed. Avoid contact with skin, eyes, or clothing. In case of
contact, flush with water. Avoid breathing mist or dust. Do not
apply, drain, or flush equipment on or near desirable trees or other
plants, or on areas to which their roots extend. Do not contaminate
any body of water (58).
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.
25. Morgan, D.P. 1982. Recognition and management of pesticide
poisonings, 3rd ed. U.S. Environmental Protection Agency,
Washington, DC. 120 pp.
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.
63a. Elanco Products Company, Div. of Eli Lilly and Co. 1974.
Technical report on Spike. Indianapolis, IN.