CA1167271A - Low-oil basal herbicidal compositions and methods - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE

Novel herbicidal concentrates contain (a) at least one brush-controlling herbicide, and (b) one or more of the following surfactants (i) a combination of alkaryl polyoxyethylene glycol mixed with petroleum distillate, alkyl sulfate and alkyl amine acetate; (ii) polyalkylene oxide block copolymer; (iii) blends of polyamine salts and metal salts of alkyl aromatic sul-fonic acid with polyoxyalkylene glycols or (iv) a com-bination of any two or more of any of the surfactants of classes (i) - (iii). The concentrates are combined with diesel oil or fuel oil type solvents and a major proportion of water to form low-oil basal herbicidal sprays effective in the kill and control of brush upon basal or foliar application thereto.

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Description

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~L. 72 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 :: : : :
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 - 2a -: ~ i I~CJ

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

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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.

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 26,180-F 11-::
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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.

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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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- l s -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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Claims (8)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. 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 the 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 polyoxy-ethylene 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;
iii) blend of polyamine salts and metal salts of alkyl aromatic sulfonic acid with polyoxyalkylene glycols;
and (d) a major proportion of water.

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2. The spray of Claim 1 wherein said herbicide is an ester or salt of [(3,5,6 trichloro-2-pyridinyl)oxy]acetic acid (triclopyr), 2,4,5-T, 2,4-D, 4-amino-3,5,6 trichloro picolinic acid (picloram), 3,6-dichloropicolinic acid or combinations thereof.

3. The spray of Claim 1 wherein said petroleum distillate is diesel fuel or No. 2 fuel oil.

4. The spray of Claim 1 wherein said surfactant is a poly-oxyethylene polyoxypropylene block copolymer having a molecular weight of about 4400 and a polyoxyethylene content of about 40 percent by weight.

5. The spray of Claim 1 wherein said surfactant is a blend of a polyamine salt and metal salt of dodecylbenzene sulfonic acid with nonylphenyl polyoxyethylene having about 15 oxyethylene groups.

6. The spray of Claim 1 wherein said herbicide is present in an amount of from 0.01 to 60 percent by volume.

7. The spray of Claim 1 wherein said petroleum distillate solvent is diesel oil, No. 1 fuel oil, No. 2 fuel oil or kerosene.

8. A method for the kill and control of brush which comprises contacting the brush to be controlled with the composition of Claim 1, 2 or 3.