Plant protecting and regulating compositions – Plant growth regulating compositions – Organic active compound containing
Reexamination Certificate
2003-05-22
2004-03-23
Clardy, S. Mark (Department: 1616)
Plant protecting and regulating compositions
Plant growth regulating compositions
Organic active compound containing
C504S211000, C504S214000, C504S313000, C504S323000, C504S343000, C504S348000
Reexamination Certificate
active
06710018
ABSTRACT:
FIELD OF THE INVENTION
A means of enhancing the effectiveness of post-emergent herbicides comprises the addition of an effective amount of at least one carboxylic acid diester to a post-emergent herbicide.
BACKGROUND OF THE INVENTION
Herbicides are generally classified into two groups—those having significant foliar use and those primarily applied into the soil. Herbicides with significant foliar use, generally described as post-emergent herbicides, are further divided into three major categories based on translocation patterns and initial plant symptoms: (a) translocated herbicides showing initial symptoms on new growth; (b) translocated herbicides showing initial symptoms on older growth; and (c) non-translocated herbicides showing initial localized injury. Each of these categories may further be subdivided according to herbicidal mode of action, i.e., auxin-type growth regulators; aromatic amino acid (EPSDS) inhibitors; branched-chain amino acid (ALS/AHAS) inhibitors; carotenoid pigment inhibitors; lipid biosynthesis (ACCase) inhibitors; organic arsenicals; “classical” photosynthesis inhibitors; “rapidly acting” photosynthesis inhibitors; Photosystem I (PSI) energized cell membrane destroyers; protoporphyrinogen oxidase [Protox (PPO)] inhibitors; and glutamine synthesis inhibitors. Of these, the most popular are glyphosate and salts of glyphosate including the monoammonium, diammonium and isopropyl ammonium salts disclosed in U.S. Pat. Nos. 5,998,332; 4,507,250; 4,481,026; 4,405,531; 4,315,765; 4,140,513; 3,977,860; 3,799,580; and 3,853,530 (including the commercial products Roundup® and Touchdown®), sulfonylurea, (sold under the tradename Classic® by E.I. duPont de Nemours and Co.), glufosinate, first reported as a herbicide in Schwerdtle, et. al. “Z. Pflanzenkr. Pfanzenschutz. Sonderheft IX. p. 431 (and now including the commercial product Finale®), oxyfluorfen, disclosed in U.S. Pat. No. 3,798,276 (and now commercially sold as Goal®), imazamox, discovered by American Cyanamid (now commercially available as Raptor®), clethodim, first reported by Kincade, et. al. in Proc. Br. Crop Prot. Conf. Weeds in 1987 (now commercially sold as Select®), sethoxydim, discovered by Nippon Soda in Japan (now commercially sold as Poast®), quizalofop, disclosed in U.S. Pat. No. 4,629,493 (now commercially sold as Assure®), fenoxaprop, first reported by Bieringer, et. al. in Proc. Br. Crop Prot. Conf. Weeds in 1982 (now commercially sold as Fusion® and Acclaim), fluazifop, disclosed in British Patent 1,599,121 (now commercially sold as Horizon 2000 and Fusilade DX) and bipyridilium salts first disclosed in British Patent 813,531 (commercially sold as Paraquat® and Diquat®) amongst others.
Post-emergent herbicides are generally slow acting and usually take days or even weeks to show a visual effect on the weeds and grasses to which they have been applied. This is undesirable from the user's standpoint. U.S. Pat. No. 5,994,269 discloses a means of achieving a more rapid visual sign of herbicidal activity by the addition of an activator to glyphosate. However, the time to achieve the desired effect is too long. Furthermore, the disclosed method does not permit the use of less post-emergent herbicide. Alternatives are therefore needed.
Along with the need to obtain a faster time for visualization of the herbicidal effect, it is further desired to develop a means which mandates less of the herbicidal active ingredient than is now employed. The reduction in the amount of the herbicidal active ingredient is desired since such chemicals are generally toxic and non-biodegradable.
SUMMARY OF THE INVENTION
It has been discovered that the herbicidal activity of post-emergent herbicides is enhanced by the addition, to the post-emergent herbicide, of least one carboxylic acid diester of the formula:
ROOC(CH
2
)
n
COOR′ (I)
wherein R and R′ are independently selected from a C
1
to C
4
alkyl group and n is from about 5 to about 9. These diesters are based on acids occurring in nature and thus have low toxicity and high biodegradability. Further, the introduction of such diesters to a post-emergent solution, emulsion or suspension permits utilization of reduced amounts of the post-emergent herbicide while still providing effective weed control. Additionally, use of the composition of the invention reduces the time required for systemic phytotoxic symptoms to appear on the target weed.
In accordance with the method of the invention, diesters of C
7
to C
11
linear dibasic acids, usually in admixture with a surfactant or emulsifier, are added to a herbicidal composition and the resulting mixture is applied to the target weed. The target weed starts to wilt and turn brown within hours. Necrosis has been seen, for instance when dimethyl azelate is added to glyphosate, to approach 100% within twenty-four to thirty-six hours of treatment compared to minimal necrosis times of three to four days without the diester.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
The effectiveness of post-emergent herbicides is dramatically improved by addition of a compound of formula (I) to a post-emergent herbicide prior to its application to the vegetation. The compound of formula (I) is at least one carboxylic acid diester of the formula:
ROOC(CH
2
)
n
COOR′ (I)
wherein R and R′ are independently selected from a C
1
to C
4
alkyl group and n is from about 5 to about 9. R and R′ on any given compound of formula (I) may be the same or different alkyl group. In a preferred embodiment, n is 7 or 8. Particularly desirable esters are the dimethyl, diethyl, diisopropyl and dibutyl esters. Especially preferred as the carboxylic acid diester of formula (I) are the lower alkyl diesters of pimelic, suberic, azelaic, sebacic and undecanedioic acids, for example, the methyl or ethyl esters. Mixtures of two or more of the carboxylic acid diesters may further be employed.
The composition applied to the vegetation of the invention may further contain a diluent. Any liquid in which formula (I) is soluble or miscible may be employed as a diluent. As a post-emergent, the herbicidal compositions of the invention are preferably applied to the locus of the unwanted vegetation as an aqueous mixture or emulsion.
When a compound of the formula (I) is added to a post-emergent herbicidal composition
(a) either as a water emulsion or
(b) by diluting a commercial herbicidal concentrate to a herbicidally effective concentration [with a water emulsion of formula (I)]
and the resulting mixture is applied to weeds according to the herbicide manufacturers recommendation, the weeds exhibit a visual phytotoxic effect in less time than would be obtained with the herbicide in the absence of the compound of formula (I). As an example, weed and grass necrosis may approach 100% within 24 hrs. with glyphosate in combination with dimethyl azelate, compared to 3-4 days or longer without the addition of dimethyl azelate.
Furthermore, with the addition of a compound of formula (I) such as dimethyl azelate, to the post-emergent herbicide, less of the post-emergent herbicide than specified by the manufacturer can be used to achieve the same herbicidal result as would be obtained using the herbicide suppliers' recommended amount in the absence of dimethyl azelate.
The herbicidal composition of the invention containing a compound of formula (I) may be applied to the locus of the unwanted vegetation in effective amounts in the manner normally used with the herbicide without the addition of the compound of formula (I). Concentrations of the post-emergent herbicide in the herbicidal composition of the invention will vary depending on the herbicide and the weeds to be controlled but the concentration of the compound of formula (I) in the final herbicidal composition is preferably between from about 0.5 to about 5.0 % by weight of the herbicidal composition, preferably between from about 1.5% to about 3.0% by weight. This preferred amount of compound of formula (I) is independent of the selection o
Clardy S. Mark
Falcon Lab LLC
Locke Liddell & Sapp LLP
LandOfFree
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