oryzalin (Surflan, Ryzelan) Herbicide Profile 2/85
CHEMICAL NAME: 3,5-Dinitro-N4,N4-dipropylsulfanilamide (56)
TRADE NAME(S): Surflan, Ryzelan, Dirimal (56)
FORMULATION(S): Wettable powder (75 WP) and 4 pounds/gallon aqueous
TYPE: Dinitrotoluidine herbicide
BASIC PRODUCER(S): Elanco Products Co.
Div. of Eli Lilly and Co.
740 South Alabama St.
Indianappolis, IN 46285
STATUS: General use
PRINCIPAL USES: For control of annual grasses and broadleaf weeds in
conventional and no-till soybeans, cotton (Texas only), bearing and
nonbearing fruit trees, nut trees, vineyards, and established
APPLICATION METHOD(S): Oryzalin should be applied as a preemergence
spray to the soil surface. In soybeans, if no rain occurs for 7 to 10
days after application, oryzalin can be shallowly incorporated without
reducing its herbicidal activity. For use on crops in areas of seasonal
rainfall, for example in fruit and nut crops, vines, ornamentals and
noncropland areas, applications of oryzalin should be made during the
rainy season so that rainfall will move it into the weed germination
At recommended rates, oryzalin is effective for controlling many
annual grass and broadleaf weeds such as: barnyardgrass (Echinochloa
crusgalli), annual bluegrass (Poa annua), brachiaria (Brachiaria sp.),
browntop panicum (Panicum fasciculatum), crabgrasses (Digitaria sp.),
crowfootgrass (Dactyloctenium aegyptium), Southwestern cupgrass
(Eriochloa gracilis), fall panicum (Panicum dichotomiflarum), foxtails
(Setaria sp.), goosegrass (Eleusine indica), seedling johnsongrass
(Sorghum halepense), wild oat (Avena fatua), Texas panicum (Panicum
texanum), carpetweed (Mollugo verticillata), common purslane (Portulaca
oleracea), Florida purslane (Richardia scabra), lambsquarters
(Chenopodium album), pigweeds (Amaranthus sp.), chickweed (Stellaria
media), and prostrate spurge (Euphorbia supina) (58).
Season-long control may be expected. Sometimes initial grass
control is weak but this can be overcome with a light soil cultivation.
Partial control of velvetleaf, smartweed, spurge, nightshade, morning
glory, teaweed and ragweed has been obtained. Being used with other
herbicides to increase the weed spectrum (8b).
II. PHYSICAL PROPERTIES
MOLECULAR FORMULA: C12 H18 N4 O6 S (62)
MOLECULAR WEIGHT: 346.4 (62)
PHYSICAL STATE: Yellow-orange crystalline solid (pure compound) (58);
yellow-orange crystalline solid (technical grade)
ODOR: No appreciable odor (pure compound) (58)
MELTING POINT: 141-142 C (pure compound) (58); 141-142 C (technical
VAPOR PRESSURE: <1 x 10-7 mmHg at 30 C (pure compound) (58)
SOLUBILITY: 2.4 mg/l water at 25 C (technical grade) (62)
III. HEALTH HAZARD INFORMATION
OSHA STANDARD: NA
NIOSH RECOMMENDED LIMIT: NA
ACGIH RECOMMENDED LIMIT: NA
A. ACUTE TOXICITY
DERMAL: The application of 2g of Surflan 75 W per kg of body
weight to the shaved and abraded backs of rabbits for 24 hours caused
only slight irritation which cleared rapidly. No other signs of
toxicity were observed. No local irritation or systemic toxicity was
observed when 2 ml of undiluted Surflan AS per kg of body weight were
applied to the shaved and abraded backs of rabbits for 24 hours (58).
ORAL: LD50 = >10,000 mg tech./kg (rat, gerbil); 1000 mg/kg
(cat, chicken); >1000 mg/kg (dog) (62).
Rats were given a single oral dose of Surflan 75W and
observed for 14 days. This treatment resulted in an
LD50 of greater than 10 g per kg of body weight (58).
No deaths occurred when rats were given a single oral
dose of 2 ml of undiluted Surflan AS per kg of body
INHALATION: Rats were exposed to 3.56 mg of Surflan 75 W, as
a mist, per liter of air for one hour and observed for 14 days. This
treatment caused only minor effects which cleared within 24 hours.
Rats were exposed to 5.7 microliters of Surflan AS (as a mist) per
liter for one hour and observed for 14 days. This treatment caused no
adverse effects (58).
EYES: Slight irritation, which cleared within 7 days, occurred
when rabbits were treated in one eye with 21 mg of Surflan 75W. In
rabbits the instillation of 0.1 ml per eye of undiuted Surfan AS
produced no irritation (58).
B. SUBACUTE AND CHRONIC TOXICITY:
In 2-yr feeding trials NEL for rats was 300 mg/kg diet (62).
Chronic oral exposure of rats and mice to large doses of technical
oryzalin for one year was well tolerated with no indication of
cumulative toxicity or serious adverse effects. Daily oral doses of
18.75 mg of oryzalin per kg of body weight administered to dogs for
three months were well tolerated with no toxic effects. Oryzalin fed
as a large component of the diet to pregnant rats during the period of
organogenesis and early fetal development resulted in no adverse
effects on either the dams or their progeny (58).
IV. ENVIRONMENTAL CONSIDERATIONS
The LC50 (96 hr) for goldfish fingerlings is >1.4 mg/l (62).
Laboratory and field studies indicate no undue hazard to fish
from oryzalin added to water at recommended rates and above (58).
Behavior In Or On Soils
1. Adsorption and leaching characteristics in several soil types:
Oryzalin leaches to a limited extent under natural rainfall
conditions. Organic matter and clay content of the soil
influence the application rate for herbicidal activity.
2. Microbial breakdown: Microorganisms are believed to play a role
in the degradation and disappearance of oryzalin from soil. No
specific soil organism has been identified as responsible for the
3. Loss from photodecomposition and/or volatilization:
Photodecomposition of oryzalin has been demonstrated in
laboratory studies. Volatilization from soil surfaces is minimal
and does not reduce the herbicidal effectiveness of oryzalin as a
4. Resultant average persistence at recommended rates: Field
studies with 14C oryzalin have indicated its rapid
biodegradability. Oryzalin applied at the recommended rate has
not caused injury to succeeding crops under warm, moist soil
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
KNOWN OR SUSPECTED ADVERSE EFFECTS: Slightly to moderately irritating
to skin, eyes, and mucous membranes. These agents do not uncouple
oxidative phosphorylation (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 amounts 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 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 precautions:
(1) If the victim is unconscious or obtunded and
facilities are at hand, insert an ENDOTRACHEAL
TUBE (cuffed, if available) prior to gastric
(2) Keep victim's HEAD BELOW LEVEL OF STOMACH
during intubation and lavage (Trendelenburg,
or 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
Technical material is a flammable solid. For the formulated
wettable powder, use ordinary precautions for handling dust or wettable
powder formulations (58).
Compatible with most other wettable powder formulations and
fertilizers if not highly alkaline. Oryzalin is not significantly
influenced in its sprayability by water hardness. Oryzalin is not
VIII. PROTECTIVE MEASURES
STORAGE AND HANDLING: Harmful if swallowed or absorbed through the
skin. Avoid contact with skin, eyes or clothing. In case of contact,
flush with water. Do not contaminate foodstuffs or feeds. Direct
contamination of any body of water with the wettable powder may kill
fish. Do not contaminate any body of water by direct application,
cleaning of equipment or disposal of wastes. The shelf life of these
formulations is more than 2 years (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.