Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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LOW-OIL BASAL HERBICIDAL COMPOSITIONS
AND METHODS
It is known that when applying brush control-
ling herbicides by a basal application for brush control
it is desirable to dissolve the herbicide in a non-
-aqueous organic solvent medium, preferably petroleum
distillates such as diesel oil or fuel oil. The pe-troleum
distillate type solvents provide for penetration of the
herbicide through the bark of the brush to be controlled.
In recent years the fuel shortage and cost
o basal spray oils have brought forth the need for sub-
stitutes for these diesel oil or fuel oil type solvents.
It has been su~gested that water and a spray adjuvant,
such as a surfactant be substituted or a portion of the
basal composition solvents. However, such a mixture of
water and a surfactant has not been found effective in
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replacing all or a major portion of the basal spray oil
~ solvents.` Moreover, not all surfactants are compatible
; ~ ~ with the herbicides, thus successful formulation of a
surfactant and herbicide into a final low-oil basal
herbicidal product has not been adequately achieved.
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The present invention is directed to basal herbicidal
concentrate compositions which can be admixed with water and oil to
form low-oil basal spray compositions which are useful in the
control of undesirable plants and especially in brush control.
According to the present invention, there is provided
a low-oil basal herbicidal spray comprising:
(a) an effective amount of at least one brush-controlling
herbicide;
(b) a petroleum distillate solvent present in an amount
of from 10 to 50 percent by volume of tAe total
spray composition;
(c) from 0.01 to 60 percent by volume of at least one
or more surfactant independently selected from the
group consisting of
i) a combination of alkaryl polyoxyethylene glycol
mixed with petroleum distillates, alkyl sulfate
and alkyl amine acetate;
ii) polyalkylene oxide block copolymer having a
molecular weight of 1000 to 14,000;
~0~ iii) blend of polyamine salts and metal salts of
alkyl aromatic sulfonic acid with polyoxy-
alkylene glycols; and
(d) a major proportion of water.
Preferably said herbicide is an ester or salt of [(3,5,6
trichloro-2-pyridlnyl)oxy]acetic acid (triclopyr), 2,4,5-T, 2,4-D,
~; ~4-amino-3,5,6 trichloro picolinic acid (picloram), 3,6-dichloro-
picolinic acid or combinations thereof.
Preferably, the above mentioned herbicidal concentrates
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are combined wlth petroleum distillates, such as diesel oil,
kerosene or fuel oil type solvents (No. 1 or No. 2 Euel oil), and
a major proportion of water, to form a novel low-oil basal
herbicidal spray composition useful in the kill and control of
brush.
The present invention also pertains to an improved
method of controlling undesired brush and other woody vegetation
in which the low-oil basal
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herbicidal spray composition of the invention is applied
either to the bark as a basal spray or to the vegetation
as a foliar spray.
When used herein, the term "basal application"
refers to the application of a herbicide to the base
portion of a plant or tree, while the term "basal
field spray or concentrate" refers to a composition
for basal application.
When used herein, the term "brush" refers
broadly to any deep rooted perennial broadleaf plant
such as trees, bushes and weeds having a woody bark-
-like stem or trunk covering and is inclusive of
seedling trees and other woody vegetation six inches
in height or greater.
When used herein, the term "kill and control"
means eradication and/or severe stunting of the brush
treated according to the invention and sensitive to
the herbicide used. The kill and control effect is
evidenced by, e.g., brownout and topkill of the treated
woody vegetation. Brownout refers to leaves on such
vegetation turning from a green color to brown. Top-
kill refers to the killing of the apical and adjacent
top portions of the treated woody vegetation. Xill
and control of brush in an area means eradication and/or
severe stunting of substantially all of the undesired
brush and other woody vegetation, in the treated area,
which is sensitive to the herbicide employed.
It has been found unexpectedly that when one
or more surfactants of one or more of the following
classes
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(i) a combination of alkaryl polyoxethylene
glycol mixed with a petroleum distillate,
alkyl sulfate and alkyl amine acetate;
(ii) polyalkylene oxide block copolymer; and
(iii) blend of polyamine salt and a metal salt
of alkyl aromatic sulfonic acid with poly-
oxyalkylene glycol
is combined with a brush controlling herbicide in a
suitable amount, that water may be combined therewith and
substituted for up to 90 percent of the diesel oil or fuel
oil type solvent conventionally employed in basal sprays
while retaining substantially the same herbicidal activity
as the conventional basal sprays. The surfactants o~
the specified classes provide for penetration of the
agueous herbicidal composition through the bark of the
brush or other woody vegetation.
Exemplary of the surfactants of class ~i~
above is the commercially available product TRONIC~
surfactant, hereinafter more fully characterized, which
lS also a preferred surfactant.
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The suitable polyalkylene oxide block co-
polymers of class (ii) above, such as polyoxyethylene
polyoxypropylene block copolymers, have a molecular
weight of from lO00 to 14,000 and preferably have a
25~ ~ polyoxyethylene oxide content of from 10 to 80 percent
by weight. A preferred~surfactant of this class is
a polyoxyethylene polyox~propyIene block copolymer
of the formula: ~
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HO(CH2CH20~a(CHCH20)b(CH2CH20)C
CH3
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wherein b is a whole number greater than 14 and a and c
are whole numbers selected so that the polyoxyethylene
portion amounts to from 20 to 80 percent by weight of
the polymer. An especially preferred compound is a
polyoxyethylene polyoxypropylene block copolymer having
about 40 percent by weight polyoxyethylene content and
a molecular weight of about 4,400 which is available
commercially as PLURONIC~ L-64 surfactant from BASF
Wyandotte Inc.
Suitable blends of polyamine salts and metal
salts of alkyl aromatic sulfonic acid with polyoxyalkylene
glycol of class (iii) above are described in Kirk-Othmer,
Encyclopedia of Chemical Technology, 2nd Edition,
Vol 19:503-593 and are also described in U.S. Patent
2,898,~67.
Examples of thç alkyl aromatic sulfonic acid
portion of the surfactant blends are the polyamine salts
and metal salts of dodecylbenzene sulfonic acid or tri-
decylbenzenesulfonic acid wherein the polyamine has from
two to four carbon atoms between amine groups and the
metal ion is an alkali metal or alkaline earth metal
cation.
~: Examples of the polyalkylen~ glycol portion
of the surfactants are polyglycol ethers of nonylphenol
~ ~5 having from 8 to 40 oxyethylene groups and polyoxyethy-
: lene ethers of dodecylphenol having from 8 to 40 oxy-
ethylene groups. A preferred surfactant is SPONTO~ 712,
a commercially available product, which comprises about
25 mole percent nonyl phenol having about 15 ethylene
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oxide groups per polymer molecule in combination with
polyamine salts and metal salts of dodecylbenzene sul-
fonic acid.
Examples of surfactants of each of the classes
herein specified and employed in the present invention
are described in Kirk Othmer, supra.
Suitable brush-controlling herbicides employed
in the present composition are the presently known her-
bicidal phenoxy alkanoic acid, pyridinyloxy alkanoic
acid, benzoic acid or picolinic acid derivatives or
combinations of two or more of said herbicides. Examples
of such herbicides include 2,4,5-trichlorophenoxy acetic
acid (2,4,5-T~, 2,4-dichlorophenoxy acetic acid (2,4-D),
2,4-dichloropropionic acid (2,4-DP), 2-(4-chloro-o-tolyl)-
oxypropionic acid (MCPP3, silvex, triclopyr, dicamba, and3,6-dichloropicolinic acid. The above-mentioned herbi-
cides are usually compounds in the form of esters or
salts. A particularly effective herbicide is a mixture
of an iso-octyl ester of 4-amino 3,5,6-trichloropicolinic
acid and propyIene glycol iso-butyl ether esters of
2,4,5-T. Another particularly effective herbicide is
~triclopyr.
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The herbicides used in making up the compo-
sitions of the invention are conventionally and con-
~ veniently supplied in the form of concentrated solutionsin inert solvents such as heavy aromatic naphtha having
a distillation range from 160 to 293C, methanol or
toluene. As a consequence, the present compositions,
as a practical matter, contain such inert solvent
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although the presence of such solvent is not essential
to the performance of -the final low-oil aqueous basal
spray compositions of the invention.
At least one herbicide and at least one or more
surfactant selected as described above are admixed to
form a herbicidal concentrate useful in making low-oil
basal sprays. Usually the surfactant will comprise from
1 to 99 percent by weight of the concentrate while the
balance comprises the herbicide and from 1 to 9B percent
by weight of an inert solvent such as a heavy aromatic
naphtha.
The herbicidal concentrate, containing at
least one herbicide in an amount of from 0.1 to 99
percent by weight and a surfactant, as described herein,
is mixed with a petroleum distillate such as, a diesel
oil or fuel oil type solvent and a major proportion of
water to form the present low-oil basal field spray.
A preferred fuel oil type solvent is No. 2 fuel oil.
While the order in which these ingredients are to be
mixed is not critical, it is advantageous to mix the
petroleum distillate with the herbicidal concentrate to
form a premix and then dilute the premix with the water
to form a field spray. When diluting the premix it is
advantageous to slowly add it to about half the total
amount of water that will be present in the field spray
with continuous agitation after which the other half
of the water is added. If -the water is added to the
premix a thick invert or water-in-oil emulsion may form
which may be hard to break. This field spray is then
applied using known hasal application techniques for
the kill and control of brush.
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Alternatively, the low-oil herbicidal com-
posi-tions of the present invention may be applied as
a foliar spray for the kill and control of brush.
The above-mentioned field spray contains the
following varying percentages by volume of ingredients:
herbicide (including solvents
(and inerts).................. 0.01-60% v/v
surfactant..................... 0.01-60% v/v
oil...... ~................................... 10-50% v/v
aqueous diluent................ 10-90% v/v
The amounts of ingredients selected for a given brush-
-controlling operation will depend on the individual
herbicide, surfactant, oil or aqueous diluent employed
and the optimum concentration is determined by tech-
~niques known in the art. A specific example of a
suitable herbicidal spray mixture contains, by volume,
(a) 1 percent of a herbicidal mixture comprising 15.1
percent iso-octyl ester of 4-amino-3,5,6-trichloropico-
linic acid, 63.4 percent propylene glycol iso-butyl
ether esters of 2,4,S-T, 2 percent methanol and 19.5
perc~n~ heav~ aroma~ic naphtha and inerts; (b) 15 percent
; No. 2 fuel oil; (c) 0.125 percent SPONTO~ 712 surfactant
and (d) 83.875 percent water. This preferred herbicidal
spray mixture is effective for the kill and control of
brush at an application rate of about 100 gallons/acre.
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Alternatively, a low-oil basal field spray may
~; be made by admixing the~individual ingredients directly
witbout~ first acquiring or preparing a concentrate.
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The present invention provides an aqueous
basal spray having efficacy of penetration of the
brush killing herbicide component thereof through bark
substantially equal to that of conventional oil-basal
sprays while using substantially less oil. Effective
basal sprays using as little as 10 pe.rcent by volume of
oil are made by using as a spray adjuvant one or more of
the herein defined classes of surfactants. The low-oil
basal sprays described herein provide penetratlon of the
herbicide component through the bark of a tree when said
low-oil basal spray is contacted with the bark of the
tree. To eradicate or greatly suppress the growth of the
undesired woody vegetation a sufficient amount of spray
is preferably employed to wet the bark around the base
of the plant. Ordinarily from 1 to 200 gallons of spray
is employed to treat 1 acre of brush or other woody
vegetation. Preferably about 10Q gallons is employed
per acre treated. The amount of spray/acre that is
most cost effective varies depending on the herbicide
and amount of herbicide present in the spray.
It is not critical that the low-oil ~asal
herbicidal sprays of the present invention be applied
to the brllsh at a specific growing stage that the
brush is in, i.e., budding stage, dormancy stage,
flowering stage, etc. Application during any stage
will be effective. For ease of application, it is
preferred to apply the present low-oil basal sprays
while the brush is in the dormant stage.
The following examples further illustrate the
present invention and the manner by which it can be prac-
ticed.
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Example 1
The following herbicidal mixture was used
in solvent solution as the brush-controlling herbicidal
component of three spray compositions according to the
invention when testing for low-oil basal application
effectiveness:
Iso-octyl ester of 4-amino-3,5,6~trichloro
picolinic acid 15.1%
Propylene glycol iso butyl ether esters of
2,4,5-T 63.4%
Methanol 2.0%
Heavy aromatic naphtha and inerts 19.5%
100.0%
The following is a list and a description of
spray adjuvants (sur~actants) used as the surfactant
component of the compositions according to the invention:
Adjuvants
(Surfactants)
Manufacturer Description
Tronic~ Alkylaryl polyoxyethylene
~Colloidal qlycols, mixed with petroleum
Products) distillates, alkyl sulfates,
alkylamine acetate.
Pluronic~ L-64 Polyoxyethylene polyoxy-
(BASF Wyandotte~ propylene block polymers.
Sponto~ 712 Blend of oil soluble complex
(Witco Chemical Co.) amine sulfonates with polyoxy-
ethylene ethers.
All spray adjuvants (surfactants) were
incorporatPd directly into the above-men-tioned her-
bicidal mixture.
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A visual comparison of the spray adjuvants
(surfactants) diluted with the above-mentioned herbicidal
mixture is listed in Table 1.
TABLE 1
Spray Adjuvant/Herbicide Mixin~ Ratio 1-1
~iY~ Appearance
Tronic~ Turbid Solution
Pluronic~ L-64 Turbid Solution
Sponto~ 712 Clear Solution
The solutions which are turbid indicate that
the spray adjuvant is not soluble or has exceeded its
solubility in the herbicidal mixture and will separate
into two liquid phases upon storage. To overcome this,
agitation was applied to all compositions to insure
a uniform mixture before diluting them with water to
make up field sprays.
Three compositions according to the invention,
described in Table 2, were tested against a control
containing only No. 2 fuel oil and herbicide. In each
case, oil, surfactant and herbicidal mixture were first
mixed together and thereafter diluted with water.
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The test trees utilized were red maples,~
6 to 7 feet in height with a base 4 to 6 inches in
circum~erence. At application time the trees were
2;5 ~ in a late budding stage. Twenty (20) milliliters
(ml) of field spray were applied to each trunk with
application starting at 12 inches above the ground
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and extending to ground level. In most treatments
complete circumferential coverage was obtained on the
bark area between the 12 inch level and the ground
with some excess leaching to the trunk base.
All spray compositions were applled with a
Yale 50 cc Hypodermic Syringe using a Yale 17-B-D needle.
This type of e~uipment was used to insure that each tree
received e~ual amounts of spray solution.
Trees were individually rated at two weeks,
four weeks and six months after application for brownout
and topkill. A rating scale of 0-8 was employed, each
number signifying the following visible appearance:
0 - No visible effect
1 - Very Slight
2 - Slight
3 - Slight to Moderate
4 - Moderate
5 - Moderate to Severe
6 - Severe
7 - Very Severe
8 - Dead
Responses of red maple trees treated with
the field sprays and control composition are shown in
Table 2. Low-oil basal sprays containing Tronic~,
Pluronic~ L-64 and Sponto~ 712 surfactants performed
substantially equal to the control while containing a
major proportion of water in place of most of the oil.
26,180-F -12-
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Example 2: Control Field Spray
The following herbicidal field spray is pre-
pared for use as a control:
Butoxyethyl ester of triclopyr
5(containing 38.4% petroleum
distillates and inerts)............ 1.5 gallons
Oil (Diesel or Fuel)................ 98.5 gallons
100 gallons
Example 3: Low~oil Basal Field Spray
The following low-oil basal field spray is
10 prepared by mixing the following ingredient~:
~utoxyethyl ester of triclopyr
(containing 38.4% petroleum
distillates and inerts)............ 1.0 gallon
SPONTO~ 712.......................... 0.5 gallon
Oil (Diesel or Fuel................. 15.0 gallons
Water............................... 83.5 gallons
100 gallons
Example 4
The control field spray of Example 2 and the
low-oil basal field spray of Example 3 are applied to
brush in substantial accordance with the procedures of
Example 1. Both the control and the low-oil basal
spray produce comparable kill and control of brush.
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Example 5: Low-oil Basal Field Spray
The following inyredients are used to prepare
a low-oil basal field spray:
Butoxyethyl ester of triclopyr
5(containing 38.4% petroleum
distillates and inerts)............ 2.0 gallons
Diesel oil........................... 25.0 gallons
SPONTO~ 712 surfactant................ 0.5 gallon
Water................................ 72.5 gallons
100 gallons
1~ The above field spray is prepared by mixing the herbi-
cide, oil and surfactant in a separate container to
form a premix. A spray tank equipped with an agitator
is filled to the 50 gallon mark with water and then the
premix is slowly added to the water with continuous
agitation. ~fter addition of the premix the balance
; of the water is added.
Example 6
The spray of Example 5 is applied to one acre
of brush using a knapsack sprayer using a pressure of
30 pounds per square inch ~psi). The basal parts of
; brush and tree trunks are sprayed to a height of 12 to
15 inches from the ground. More spray is applied to
old or rough bark than is applied to smooth young
bark. Substantially the same effective kill and control
of the brush is accomplished as that of the control
field spray of Example 2 when applied in a similar
manner.
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