dichlorprop (Weedone, Cornox) Herbicide Profile 3/85
CHEMICAL NAME: 2-(2,4-dichlorophenoxy)propionic acid (58)
TRADE NAME(S): Weedone, Cornox (58)
FORMULATION(S): Aqueous solutions of potassium or amine salt;
isooctyl and butyl esters (56).
TYPE: Chlorophenoxy herbicide
BASIC PRODUCER(S): SDS Biotech Corp.
7528 Auburn Rd.
P.O. Box 348
Painesville, OH 44077
STATUS: General use
PRINCIPAL USES: Dichlorprop is a translocated postemergence
herbicide effective in the control of some Polygonum sp. and other
weeds in small grain cereals. It may be used either alone or in
combination with other herbicides such as MCPA, benazolin, and
dicamba. The latter mixture is an extremely effective broad spectrum
herbicide controlling such economically important weeds as Anthemis
spp., Matricaria spp., Stellaria media, Galium aparine, as well as
Polygonum spp. Dichlorprop is also used for brush control in
nonagricultural land (58).
APPLICATION METHOD(S): Postemergence foliage application (58).
Particularly effective for the control of Polygonum persicaria,
P. lapathifolium and P. convolvulus. It also controls Galium aparine
and Stellaria media but is not consistently effective against P.
II. PHYSICAL PROPERTIES
MOLECULAR FORMULA: C0 H8 Cl2 O (58)
MOLECULAR WEIGHT: 235.1 (58)
PHYSICAL STATE: White to tan crystalline solid (pure compound)
(58); yellowish solid (tech. a.i.) (56).
ODOR: Faint phenolic odor (pure compound) (58)
MELTING POINT: 116 - 117.5 C (pure compound) (58); 117.5 - 118.1 C
(technical) (56); 114 C (technical grade) (62).
VAPOR PRESSURE: Negligible at room temperature (62)
SOLUBILITY: 0.71 g/l water at 28 C (pure compound) (58); 825
ppm water at room temperature (tech. a.i.) (56).
III. HEALTH HAZARD INFORMATION
OSHA STANDARD: None established
NIOSH RECOMMENDED LIMIT: None established
ACGIH RECOMMENDED LIMIT: None established
A. ACUTE TOXICITY
DERMAL: LD50 = 1,400 mg/kg (mouse); 2.4% of solution did
not irritate skin (58).
ORAL: LD50 = 800 mg/kg (rat, tech. a.i.) (56).
LD50 = 400 mg/kg (mouse) (58).
EYES: A 1% solution did not irritate eyes (58).
B. SUBACUTE AND CHRONIC TOXICITY:
No effect noted in rats fed 12.4 mg/kg per day for 90 days (58).
In 98-day feeding trials no toxic effect was observed in rats
receiving 12.4 mg/kg daily, though slight liver hypertrophy occurred at
50 mg/kg daily (62).
IV. ENVIRONMENTAL CONSIDERATIONS
LC50 (48-hr) for bluegill was 165 mg dichlorprop-(dimethyl-
ammonium)/l; 16 mg dichloroprop-isoctyl)/l; 1.1 mg dichlorprop-(2-
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
If poisoning is suspected, do not wait for symptoms to develop.
Contact a physician, the nearest hospital, or the nearest Poison
FREQUENT SYMPTOMS AND SIGNS OF POISONING
Chlorophenoxy compounds are moderately IRRITATING to skin and
mucous membranes. Inhalation of sprays may cause burning sensations in
the nasopharynx and chest, and coughing may result. Prolonged
inhalation sometimes causes dizziness.
When INGESTED, high concentrations of chlorophenoxy compounds may
irritate the mouth, throat, and gastrointestinal tract. Prompt EMESIS,
CHEST PAIN (from esophagitis), ABDOMINAL PAIN, and DIARRHEA commonly
ensue. Injury to the GI tract does not usually progress to ulceration
or perforation. Absorbed chlorophenoxy compounds have caused
FIBRILLARY MUSCLE TWITCHING, skeletal muscle tenderness, and MYOTONIA
(stiffness of muscles of the extremities). Ingestion of very large
amounts has produced METABOLIC ACIDOSIS, fever, tachycardia,
hyperventilation, vasodilatation and sweating. Particular cases have
been characterized by coma and convulsions (25).
SKIN CONTACT: BATHE and SHAMPOO with soap and water to remove
chemicals from skin and hair. Individuals with chronic skin disease or
known sensitivity to chemicals should either avoid using these
herbicides or take extraordinary measures to avoid contact (25).
INGESTION: If substantial amounts of chlorophenoxy compounds have
been INGESTED, spontaneous emesis usually occurs. Ordinarily this
empties the stomach as effectively as intubation and lavage. If
vigorous emesis has not occurred and IF VICTIM IS FULLY ALERT, induce
EMESIS with SYRUP OF IPECAC (adults 12 years and older, 30 ml; children
under 12 years, 15 ml), followed by 1-2 glasses of water. Following
emesis, administer 30-50 gm of ACTIVATED CHARCOAL in a slurry of 6-8
ounces tap water, to limit absorption of herbicide remaining in the gut
INHALATION: If symptoms of illness occur during or following
inhalation of spray, REMOVE victim FROM CONTACT with the material for
at least two days. Allow subsequent contact with chlorophenoxy
compounds only if effective respiratory protection is practiced (25).
EYE CONTACT: FLUSH contaminating chemicals from eyes with copious
amounts of clean water for 10-15 minutes (25).
NOTES TO PHYSICIAN:
1. IF CONSCIOUSNESS LEVEL IS DEPRESSED or other signs of NEUROTOXICITY
appear, SUSPECT additional or alternative ingested toxicants.
Evacuate the stomach by INTUBTION, ASPIRATION, and LAVAGE. Because
petroleum distillates are commonly included in chlorophenoxy
formulations, gastric intubation incurs a risk of hydrocarbon
pneumonitis from aspiration. For this reason:
A. If victim is unconscious or obtunded and facilities are at
hand, insert an ENDOTHRACHEAL TUBE (cuffed, if available) prior
to gastric intubtion.
B. Keep victim's HEAD BELOW LEVEL OF THE STOMACH during intubation
and lavage (Trendelenburg, or left lateral decubitus, with head
of table tipped downward). Keep victim's head turned to left.
C. ASPIRATE PHARYNX as regularly as possible to remove gagged or
vomited stomach contents.
After aspiration of gastric contents and washing of stomach,
instill 30-50 gm of ACTIVATED CHARCOAL in 3-4 ounces of water
through the stomach tube to limit absorption of remaining toxicant.
Do NOT instill milk, cream, or other materials containing vegetable
or animal fats, as these are likely to enhance absorption.
2. If bowel movement has not occurred in 4 hours and patient is fully
conscious, give SODIUM SULFATE, 0.25 gm/kg, as a cathartic.
Magnesium sulfate and citrate, in comparable dosages, are equally
suitable if renal function is adequate. Retained magnesium may
depress CNS function.
3. In SEVERE POISONINGS by very large amounts of ingested
chlorophenoxy acids, forced ALKALINE DIURESIS may save the victim's
life. Assess serum electrolyte concentrations, and serum and urine
pH. If a metabolic acidosis is present, infuse solutions of sodium
bicarbonate at rates sufficient to keep the urine distinctly
alkaline, continuing until plasma concentrations of chlorophenoxy
compounds are less than about 10 ug/ml. (Prescott, L.F. et al.,
Br. J. Clin. Pharmacol. 7:11 (1979) (25).
VI. FIRE AND EXPLOSION INFORMATION
To be developed.
Dichlorprop is corrosive to metals in the presence of water;
concentrated solutions (480 g a.e./l) do not corrode tin plate or iron
if pH is greater than or equal to 8.6 and temperature <70 C (62).
VIII. PROTECTIVE MEASURES
STORAGE AND HANDLING: Avoid spray drift to susceptible broadleaf
plants that are desirable such as cotton, soybeans, and tomatoes. If
stored below freezing, it may be necessary to warm to 40 F and agitate
before using (56).
IX. PROCEDURES FOR SPILLS AND LEAKS
IN CASE OF EMERGENCY, CALL, DAY OR NIGHT
PESTICIDE TEAM SAFETY NETWORK/CHEMTREC
X. LITERATURE CITED
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.