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maleic hydrazide (Royal MH-30) Herbicide Profile 3/85

                                  maleic hydrazide
      CHEMICAL NAME:      1,2-dihydro-3,6-pyridazinedione (58)
      TRADE NAME(S):      Royal MH-30, Sprout-Stop, Retard, Fair Plus, etc.
      FORMULATION(S):     Water-soluble liquids of the diethanolamine salt or
                          the potassium salt (56).
      TYPE:               Pyridazinone herbicide
      BASIC PRODUCER(S):  Drexel Chemical Co.     Fairmont Chemical Co., Inc.
                          2487 Pennsylvania St.   117 Blanchard St.
                          P.O. Box 9306           Newark, NJ 07105
                          Memphis, TN 38109
                          Uniroyal Chemical
                          Div. of Uniroyal, Inc.
                          Elm St.
                          Naugatuck, CT 06770
      STATUS:  General use.  RPAR issued 10/28/77, criteria possibly
      met or exceeded:  oncogenicity, mutagenicity, reproductive
      effects.  Returned to the Registration Process 6/28/82.  Additional
      reproductive and mutagenicity studies have been performed on K-MH as
      required.  Registrants decided not to perform similar tests on DEA-MH
      and thus DEA-MH was suspended 11/81 (22).
      PRINCIPAL USES:  Primary uses include sucker control on tobacco,
      sprout inhibition in stored onions and potatoes, frost protection in
      citrus and turf and roadside maintenance.  Maleic hydrazide has
      herbicidal activity on quackgrass, wild onions, and wild garlic (58).
           Maleic hydrozide is recommended for the temporary growth
      inhibition of various trees, shrubs and grasses (56).
      APPLICATION METHOD(S):  Used as a over-the-top foliar spray.  Dosage
      and stage of plant development are critical factors (58).
                                 I.  EFFICACY
           To be developed.
                              II.  PHYSICAL PROPERTIES
      MOLECULAR FORMULA:  C4 H4 N2 O2 (58)
      MOLECULAR WEIGHT:   112.1 (58)
      PHYSICAL STATE:     White solid (pure compound) (58); colorless
                          crystalline solid (dry technical grade, >99% pure)
      ODOR:               Odorless (pure compound) (58)
      MELTING POINT:      300  C (pure compound) (58); 292-298 C (technical
                          grade) (62).
      DECOMPOSITION TEMPERATURE:  About 260 C (pure compound) (58)
      BOILING POINT:      Does not boil (pure compound) (58)
      VAPOR PRESSURE:     Essentially zero (pure compound) (58)
      SOLUBILITY:         6000 ppm at 25 C (pure compound) (58)
                          III.  HEALTH HAZARD INFORMATION
      OSHA STANDARD:  None established
      NIOSH RECOMMENDED LIMIT:  None established
      ACGIH RECOMMENDED LIMIT:  None established
           A.  ACUTE TOXICITY
               DERMAL:  LD50 = >2000 mg/kg (rabbit) (62).
                        LD50 = >8000 mg/kg (rabbit, Royal MH) (58).
                        Moderate skin irritation for rabbits (58).
               ORAL:    LD50 (rat) = 6950 mg/kg (sodium salt of MH); 3900
                        mg/kg (MH-30); 14145 mg/kg (Royal MH); >5000 mg/kg
                        (technical MH) (58).
               INHALATION:  LC50 = >20 mg/l air (rat) (62).
                            LC50 = >200 mg/l air (rat, Royal MH) (58).
               EYES:    Severe eye irritation for rabbits (58).
           Two-year feeding studies of rats at the 6.0% level of sodium salt
      of MH (equivalent to about 5% MH acid equivalent) showed no toxicity
           In 2-yr. feeding trials, including a 3-generation reproduction
      study, rats receiving 50,000 mg sodium salt/kg diet showed no
      ill-effect.  There was no oncogenic effect by the potassium salt in
      mice; in a 1-yr. trial on dogs with 20,000 mg sodium salt/kg diet mild
      reversible effects were noted.  Maleic hydrazide gave negative results
      in mutagenicity tests (62).
                         IV.  ENVIRONMENTAL CONSIDERATIONS
      Behavior In Or On Soils
      1.   Microbial breakdown:  Rapidly broken down by soil microorganisms.
      2.   Average persistence at recommended rates:  No residual effect (58).
           No mortality at 10.0 ppm to bluegills and fatheads (58).
           LC50 (96-hr) is:  for bluegill 1608 mg/l; for rainbow trout 1435
                mg/l; for Daphnia spp. 107 mg/l (62).
           LD50 = >10,000 m/kg (mallard duck, bobwhite quail) (62).
           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:  Slightly irritating (25).  No
      symptoms of poisoning encountered in field usage (58).
           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 amounts of
      fresh water for 15 minutes (25).
      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 distillates) 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
                     (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.
      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.
      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, a water solution (58).
                               VII.  COMPATIBILITY
           If in the presence of a strong acid, the MH acid may precipitate.
      Do not use concentrate through brass nozzles as the amine content may
      cause erosion (58).
                             VIII.  PROTECTIVE MEASURES
      STORAGE AND HANDLING:  The formulation has been held as long as 10
      years with no breakdown.  Light and temperature stability are very good
      PROTECTIVE CLOTHING:  No protective clothing required (58).
                        IX.  PROCEDURES FOR SPILLS AND LEAKS
                      IN CASE OF EMERGENCY, CALL, DAY OR NIGHT
                                   (800) 424-9300
                               X.  LITERATURE CITED
      22.  U.S. Environmental Protection Agency, Office of Pesticide
               Programs.  1983.  June 1983 status report on rebuttable
               presumption against registration (RPAR) or special review
               process, registration standards and the data call in
               programs.  Washington, DC.  45 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.