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tebuthiuron (Graslan, Spike) Herbicide Profile 2/85

                                    tebuthiuron
      CHEMICAL NAME:      N-[5-(1,1-dimethylethyl)-1,3,4-thiadiazol-z-yl]-
                          N,N-dimethylurea (58)
      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
      rainfall (58).
                                   I.  EFFICACY
           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
      University.
           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
      (8b).
                             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
      TOXICOLOGY
           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
                            hr (58).
               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.
                                     Reference
           Morton, D.M. and D.G. Hoffman.  Metabolism of new herbicide
             tebuthiuron (1(5-(1,1-dimethyl-1,3,4-thiadiazol-2-yl)-1,3-dimethyl
             -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.
                                     Reference
           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
      Control Center.
      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
      treated by:
      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
           cathartic (25).
           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
           gastric lavage:
           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
           promptly (25).
                        VI.  FIRE AND EXPLOSION INFORMATION
           Not flammable (58).
                                VII.  COMPATIBILITY
           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
                                  (800) 424-9300
                      PESTICIDE TEAM SAFETY NETWORK/CHEMTREC
                               X.  LITERATURE CITED
       8b. Thomson, W.T.  1981.  Agricultural chemicals - book 2:
               herbicides.  Revised ed.  Thomson Publications, Fresno, CA.
               274 pp.
      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.
      2/27/85