Description
Since 1970, benfluralin has been registered in the United
States as a preemergent dinitroaniline herbicide. In 2004, the
US Environmental Protection Agency (EPA) conducted an
assessment to determine if pesticide products containing the
active ingredient of benfluralin were eligible for pesticide
reregistration. The criteria included meeting current human
health and safety standards, and determining if the pesticide
being used poses any unreasonable risks to human health
and the environment. Results of the US EPA assessment were
explained in the Reregistration Eligibility Decision (RED) of
benfluralin. The RED document determined that pesticides
with the active ingredient of benfluralin were eligible for
reregistration provided certain stipulations listed in the RED
document were met that included additional label requirements.
Under the Federal Insecticide, Fungicide, and Rodenticide
Act (FIFRA) Section 3, all new pesticides used in the
United States must be registered by the Administrator of the
US EPA. There are 38 products registered for benfluralin.
Chemical Properties
Yellowish-orange crystalline solid.
Commercial product is available as an emulsifiable concentrate.
Uses
A trifluoromethyl dinitroaniline selective preemergence herbicide for control of
annual grasses and some broad-leaved weeds in vegetables and turf.
Uses
A dinitroanilie heribicide used for the control of a wide range annual grass and broadleaf weeds in crops such as groundnuts, tobacco, lettuce, turf, alfalfa, clover, watermelons and sweet melons.
Uses
Benfluralin is a preemergent herbicide registered to control
monocot (one cotyledon: plant embryo with single ‘seed
leaf’) and dicot (two cotyledon: plant embryo with two
‘seed leaves’) weeded species in commercial and residential
applications. Target species for benfluralin include Johnson
grass seedlings, chickweed, lamb quarters, purslane, knotweed,
clover, and barnyard grass. Benfluralin affects seed
germination and prevents weed growth by inhibition of root
development. Absorbed by roots, benfluralin inhibits
microtubule formation by binding to tubulin, thereby disrupting
cell division and leading to microfibril disorientation.
Benfluralin can be used alone or formulated with other
structurally related preemergent herbicides. Benfluralin has been formulated with oryzalin, isoxaben, triclopyr and/or
trifluralin. Various formulated types include emulsifiable
concentrate, granules, soluble concentrate/liquid, and water
dispersed granules. Benfluralin is formulated as granules in
42 end-use products and one product in the form of water
dispersible granules. Applications can be by broadcast
(granules and fertilizer mixed) and band treatment, golf
course treatment, soil incorporated treatment, and spray
with ground/sprinkler irrigation systems. Agricultural usage
of benfluralin is predominately on lettuce, alfalfa, clover,
birdsfoot trefoil, nonbearing fruit and nut trees, and vineyards.
Production Methods
Benfluralin is synthesised through a multi-step chemical process starting with the preparation of a substituted aniline derivative. The key production step involves nitration of the aromatic ring to introduce two nitro groups, followed by alkylation to attach butyl and ethyl groups to the nitrogen atom. A trifluoromethyl group is also introduced to enhance herbicidal activity.
Definition
ChEBI: A tertiany amino compound that is 2,6-dinitro-4-(trifluoromethyl)aniline in which the hydrogens attached to the aniline nitrogen have been replaced by one ethyl and one butyl group. It is used as a pre-emergence herbicide used for the control of grass and
ther weeds in a range of food and non-food crops.
General Description
Yellow-orange solid. Herbicide.
Air & Water Reactions
Slightly water soluble.
Reactivity Profile
A dinitroaniline derivative.
Agricultural Uses
Herbicide: Selective pre-emergence herbicidal control of annual
grasses and broad-leaf weeds. Used on alfalfa, red
clover, seeded lettuce, trefoil; peanuts, certain tobaccos,
vegetables such as endive, field and French beans and
lentils.
Trade name
BALAN®; BALFIN®; BENEFEX®;
BETHRODINE®; BHULAN®; BINNELL®;
BONALAN®; CARPIDOR®; EL-110®; EMBLEM®;
FLUBALEX®; PEL-TECH®; QUILAN®; TEAM; XL 2G
Chemical class: 2,6-Dinitroaniline
Mechanism of action
Works via the disruption of microtubule dynamics. It binds to tubulin, the protein subunit of microtubules, and interferes with their structure and function. This disruption leads to the inhibition of mitosis, inhibiting root and shoot growth, ultimately leading to plant death.
Potential Exposure
Selective preemergence herbicide used
to control of annual grasses and broad-leaf weeds. Used on
alfalfa, red clover, seeded lettuce, trefoil; peanuts, certain
tobaccos, vegetables such as endive, field and French
beans, and lentils. A dinitroaniline derivative.
Environmental Fate
Soil. Benfluralin degraded faster in flooded soils under anaerobic conditions than when
oxygen was present. The major route of benfluralin degradation in flooded soil is the
formation of polar products (Golab et al., 1970) including N-butyl-N-ethyl-α,α,α-trifluoro-
5-nitrotoluene-3,4-diamine, N-butyl-N-ethyl-α,α,α-trifluorotoluene-3,4,5-triamine, N butyl-N-ethyl-α,α,α-trifluorotoluene-3,4,5-triamine, N-butyl-α,α,α-trifluoro-2,6-dinitro p-toluidine, N-ethyl-α,α,α-trifluoro-2,6-dinitro-p-toluidine, N-butyl-α,α,α-trifluoro-5-
nitrotoluene-3,4-diamine, N-butyl-α,α,α-trifluorotoluene-3,4,5-triamine, N-ethyl-α,α,α-
trifluoro-5-nitrotoluene-3,4-diamine, α,α,α-trifluoro-5-nitrotoluene-3,4-diamine, and
α,α,α-trifluorotoluene-3,4,5-triamine (Williams, 1977). The rate of degradation was high est under anaerobic conditions.
Nash (1988) reported a dissipation half-life of 2 days for benfluralin in soil.
Photolytic. Though no products were identified, benfluralin is subject to photodegra dation by UV light (Worthing and Hance, 1991). A photodegradation yield of 79% was
achieved after the herbicide in dry soil was subjected to sunlight for 7 days
Chemical/Physical. In aqueous solutions (pH 5–9 and 26°C), benfluralin is stable up
to 30 days (Worthing and Hance, 1991).
Shipping
UN3077 Environmentally hazardous substances,
solid, n.o.s., Hazard class: 9; Labels: 9—Miscellaneous
hazardous material, Technical Name Required. UN1596
Dinotoanilines, Hazard Class: 6.1; Labels: 6.1—Poisonous
materials.
Toxicity evaluation
Use of benfluralin as a preemergent herbicide results in
a direct release into the environment. Benfluralin has an
estimated Henry’s law constant of 2.91×10-4 atm-m3mol
-1
derived from a vapor pressure of 6.6×105 mmHg. Benfluralin
has a water solubility of 0.1 mg l
-1, an octanol/water
partition coefficient of Kow = 5.29 and a soil organic carbon–
water partitioning coefficient range of Koc= 9840 to
11660.
Based on the Henry’s law constant, volatilization of benfluralin
from moist soil surfaces and water surfaces is expected.
However, volatilization of benfluralin from dry soil surface is
not expected. Benfluralin is typically formulated and applied to
minimize volatilization. Benfluralin Koc value range indicates
a decreased mobility in soil. The Koc value also indicates that
benfluralin can be expected to adsorb to suspended solids and
sediment in the water column.
Incompatibilities
Incompatible with oxidizers (chlorates,
nitrates, peroxides, permanganates, perchlorates, chlorine,
bromine, fluorine, etc.); contact may cause fires or explosions.
Keep away from alkaline materials, strong bases,
strong acids, oxoacids, epoxides. Moderate heat causes
decomposition that produces toxic vapors that can form an
explosive mixture with air.
Waste Disposal
Do not discharge into drains
or sewers. Dispose of waste material as hazardous waste
using a licensed disposal contractor to an approved landfill.
Consult with environmental regulatory agencies for guidance
on acceptable disposal practices. If allowed,
Incineration with effluent gas scrubbing is recommended.
Containers must be disposed of properly by following package
label directions or by contacting your local or federal
environmental control agency, or by contacting your
regional EPA office. Ultraviolet-radiation: This liquid herbicide
is reported to be susceptible to decomposition by
UV radiation.
