trifluralin (Treflan) Herbicide Profile 2/85
CHEMICAL NAME: a,a,a-Trifluoro-2,6-dinitro-N,N-dipropyl-p-
TRADE NAME(S): Treflan, Elancolan, Trefanocide (56)
FORMULATION(S): Available in liquid (4 EC, 4 lb/gal), M.T.F. (4
lb/gal) non-freezable formulation, PRO-5 and 5% granular forms and 5 GL
formulation on limestone (56).
TYPE: Dinitrotoluidine 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: Selective preemergence herbicide (56). Crops
registered for trifluralin use: milo (PoPI); field corn (PoPI);
mustard for seed; Spanish peanuts; sugarcane (post); winter wheat;
barley; cotton; soybeans; castor beans; dry beans; rapeseed; safflower;
mung beans; snap beans; lima beans; guar; southern peas; English peas;
dry peas; okra; sugarbeets (after blocking or thinning); cantaloupes
(postplant); carrots; turnip greens (grown for processing only);
collard, kale, and mustard greens; direct-seeded broccoli, Brussels
sprouts, cabbage and cauliflower; celery; tomatoes (transplant or
direct-seeded at blocking or thinning), transplants of peppers,
broccoli, Brussels sprouts, cabbage and cauliflower; established
alfalfa; vineyards; hops; orange, grapefruit, lemon, tangerine and
tangelo trees; almond; pecan, walnut; apricot, nectarine; peach;
established spearmint and peppermint. Consult the product label for
special instructions for weed control and crop uses (58).
APPLICATION METHOD(S): Trifluralin is a preemergence herbicide which
must be soil incorporated within 24 hours after application using
equipment that breaks up large clods and mixes the soil thoroughly;
e.g., PTO-driven cultivators, hoes or tillers; double disc, rolling
cultivator, field cultivator, mulch treader, or bed conditioner.
Application and incorporation can be preplant (PPI), postplant (PoPI),
or layby (PoPI). Trifluralin may be applied by ground or aerial
equipment. Surface applications of granular formulation followed by
water incorporation to ornamental trees, flowers, and shrubs are also
The following grass and broadleaf weeds are controlled by
trifluralin: annual bluegrass (Poa annua), barnyardgrass (Echinochloa
crus-galli), signalgrass (Brachiaria sp.), bromegrass (Bromus
tectorum), cheat (Bromus secalinus), crabgrasses (Digitaria sp.), fall
panicum (Panicum dichotomiflorum), foxtails (Setaria sp.), goosegrass
(Eleusine indica), guineagrass (Panicum maximum),
johnsongrass--seedling and rhizome (Sorghum halepense), junglerice
(Echinochloa colonum), raoulgrass or itchgrass (Rottboellia exaltata),
sandbur (Cenchrus incertus), sprangletop (Leptochloa filiformis),
stinkgrass (Eragrostis cilianensis), Texas panicum (Panicum texanum),
wild cane or shattercane (Sorghum bicolor), carpetweed (Mollugo
verticillata), chickweed (Stellaria media), field bindweed (Convolvulus
arvensis), Florida pusley (Richardia scabra), goosefoot (Chenopodium
hybridum), henbit (Lamium amplex icaule), knotweed (Polygonum
aviculare), kochia (Kochia scoparia), lambsquarters (Chenopodium
album), pigweeds (Amaranthus sp.) puncturevine (Tribulus terrestris),
purslane (Portulaca oleracea), Russian thistle (Salsola kali), and
stinging nettle (Urtica dioica) (58).
Must be incorporated in top 2-3 inches of the soil with 24 hours
after application. Will not kill established weeds (56).
Tolerant weeds include velvetleaf, nightshade, Jimsonweed,
buffalobur, horsenettle, nutgrass, cocklebur, and established annual
and perennial weeds. Kills weeds sedds as they germinate. Rainfall is
not required to activate the chemical. Soil incorporation gives
greatest effectiveness. Full season weed control can be expected.
Effective on peat or muck soils up to 20% in organic matter (8b).
II. PHYSICAL PROPERTIES
MOLECULAR FORMULA: C13 H16 F3 N3 O4 (62)
MOLECULAR WEIGHT: 335.5 (62)
PHYSICAL STATE: Orange crystalline solid (pure compound) (58);
orange crystalline solid (technical trifluralin -
98% pure) (62). The technical grade is greater than
or equal to 95% pure (62).
ODOR: No appreciable odor (pure compound) (58)
MELTING POINT: 48.5-49 C (pure compound); >42 C (technical
BOILING POINT: 96 to 97 C at 0.18 mmHg (pure compound) (58)
VAPOR PRESSURE: 1.1 x 10-4 mmHg at 25 C (pure compound) (58)
SOLUBILITY: <1 mg/l water at 27 C (pure compound) (62)
III. HEALTH HAZARD INFORMATION
OSHA STANDARD: NA
NIOSH RECOMMENDED LIMIT: NA
ACGIH RECOMMENDED LIMIT: NA
A. ACUTE TOXICITY
DERMAL: Skin applications of 2000 mg/kg caused neither
toxicity nor irritation to rabbits (62). No skin
irritation or other toxicity was observed when 2.5
g of Trifluralin Technical 95% per kg of body
weight were applied to the shaved backs of rabbits
for 24 hours (58).
ORAL: LD50 = >10,000 mg/kg (rat), 500 mg/kg (mouse),
>2000 mg/kg (dog, rabbit, chicken) (62).
INHALATION: Rats were exposed to 41 mg of Treflan EC per
liter of air for one hour and observed for 14
days. This treatment caused no adverse effects
EYES: Slight irritation, which cleared within 7 days,
occurred when 36 mg of Trifluralin Technical 95%
were placed in the eyes of rabbits (58).
Moderate irritation, which cleared within 7 days,
occurred when 0.1 ml of Treflan EC was placed in
the eyes of rabbits (58).
B. SUBACUTE AND CHRONIC TOXICITY:
In 2-year feeding trials rats receiving 2000 mg/kg diet and dogs
1000 mg/kg diet suffered no ill-effect (62). Large daily doses of
trifluralin were tolerated by laboratory animals with no evidence of
acute or cumulative toxicity (58).
IV. ENVIRONMENTAL CONSIDERATIONS
The LC50 (96 hr) to bluegill fingerlings is 0.089 mg/l (62).
Behavior In or On Soils
1. Adsorption and leaching characteristics in several soil types:
Trifluralin is strongly adsorbed on soil and shows negligible
leaching. Organic matter and clay content of the soil influence
the application rate necessary for herbicidal activity.
2. Microbial breakdown: Microorganisms are believed to contribute to
the degradation and disappearance of trifluralin from soil. Using
mass inoculation or soil enrichment procedures, microorganisms
have been identified that will degrade trifluralin.
3. Loss from photodecomposition and/or volatilization: Trifluralin
is slightly volatile. Material remaining on the soil surface can
be subject to photodecomposition.
4. Resultant average persistence at recommended rates: Recommended
application rates give season long weed control. Fall-seeded
grain crops planted in soil that received trifluralin applications
the preceding spring have not been injured under warm, moist
No hazard to mammals and birds; toxic to fish if placed directly
in water. Physical properties of compound (strong adsorption on soil)
and application methods (soil incorporation) preclude possibility of
hazard to fish in recommended usage (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 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 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).
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.
Ingestions 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
left lateral decubitus, with head of table
tipped downward). Keep victim's head turned to
(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 not flammable. For the emulsifiable
concentrates use ordinary precautions for volatile solvents. Treflan
EC is classified as a combustible liquid. Closed containers may
explode due to pressure build-up when subjected to excessive heat or
intense fire (58).
No incompatibilities have been experienced with hard water. If
proper agitation is used in spray tanks and the proper mixing
instructions are followed, most pesticide tank mixes are compatible.
Treflan EC is compatible with urea-ammonium nitrate solutions when an
emulsion is first made with Treflan and water before adding to the spray
tank. Information available with complete fluid fertilizers suggests
that vigorous agitation will keep a good emulsion; spray tank adjuvants
such as Sponto 168D, Triton QS-44, and T-Mulz 734-2 are helpful. The
emulsifiable concentrates can be impregnated on granular fertilizer and
applied with the fertilizer. Trifluralin is not corrosive (58).
VIII. PROTECTIVE MEASURES
STORAGE AND HANDLING: Keep out of reach of children. Avoid freezing.
Store above 40 F. Do not store near heat or flame. Do not get in
eyes. Avoid contact with skin or clothing (56). Shelf life of the
emulsifiable concentrates is more than 2 years. They should not be
stored near the flash point. Do not contaminate foodstuffs or feeds.
Direct contamination of any body or water with trifluralin may kill
fish. Do not contaminate any body of water by direct application,
cleaning of equipment or disposal of wastes (58).
PROTECTIVE CLOTHING: Personnel must wear full protective equipment at
all times. This includes: Neoprene-coated gloves, rubber workshoes or
overshoes, latex rubber apron, goggles to protect eyes, respirator or
mask approved for toxic mist and organic vapors, overalls or rubber
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.