MXPA98008278A - Selective herbicide of m - Google Patents

Abstract

A method to selectively control undesirable vegetation in maize by applying a deductively effective amount of 2- (2-nitro-4-trifluoromethylbenzoyl) -1,3-cyclohex anodione to the site of said vegetation.

Description

SELECTIVE MAIZE HERBICIDE DESCRIPTION The present invention is directed to the use of 2- (2'-nitro-4'-trifluoromethylbenzoyl) -1,3-cyclohexanedione as a selective preemergence and postemergence herbicide in corn. The protection of the cultivation of seeds and other vegetation that inhibits the growth of the crop is a constantly recurring problem in agriculture. To help combat this problem researchers in the field of synthetic chemistry have produced an extensive variety of chemicals and chemical formulations effective in controlling unwanted growth. Chemical herbicides of many types have been described in the literature and a large number are in commercial use. Unfortunately, many of the herbicides will exhibit phytotoxicity to the desired crop as well as to the seeds, which it is expected to control. Therefore, there is a long-standing need for selective herbicides that frequently control the present seeds but do not adversely affect crop plants when herbicidally effective levels are applied. U.S. Patent 5,006,158 to Carter et al. 2'-nitro-substituted benzoylcyclohexanediones having the structure: wherein R1 and R3-R6 are hydrogen or alkyl, R2 is hydrogen, alkyl or alkoxycarbonyl; R7 is hydrogen or alkoxy; and Rs is hydrogen, halogen, alkoxy, alkyl, 0CF3, cyano, nitro, haloalkyl, optionally substituted amino, optionally substituted aminosulfononyl, alkylcarbonyl, alkoxycarbonyl or R6S (0) n wherein n is 0.1 or 2 and R6 is substituted alkyl, phenyl or benzyl. Specifically, it is described, as Compound 8D, is 2- (2'-nitro-4'-trifluoromethylbenzoyl) -1,3-cyclohexanediene. Such a compound is shown to be an effective emergency herbicide against a wide variety of grasses, broadleaf weeds and sedge when applied at a rate of 2.24 kg / ha. It has been found that said compound effectively controls a broad range of weeds typically associated with corn without exhibiting any substantial phytotoxic effect on the corn itself. This invention is directed to a method for selectively controlling undesirable vegetation in corn, comprising the application of a herbicidally elective amount of 2 (β '-nitro-' -trifluoromethylbenzoyl) -1,3-cyclohexandhex (hereinafter; r lanlc NTBC), > > a salt aqr í col arnent < - acceptable d < 1 mi ur, to the site of diclia vegetation. By the term "ugi i colarnent t acept" there is a salt, the cation of which is known and accepted in the technique for the formation of areas for agricultural or horticultural use. As used herein, the term "herbicide" is used to denote a compound that controls or modifies plant growth. The term "herbicidically effective amount" is used to indicate the amount of said compound that is capable of producing a control or modification effect. Control or modification effects include all deviations from natural development, for example, death, retardation, leaf burn, albinism, dwarfing and the like. The term "plants" refers to all physical parts of a plant, including seeds, seedlings, young trees, roots, tubers, stems, cane, lily, and fruits. NTBC is a known compound and can be produced by methods by those described in U.S. Patent 5,006,158 by Carter et al. In the practice of the present invention, NTBC is applied to the site of the vegetation that will be controlled. The production regimes will depend on the particular plant species and the degree of control desired. In general, application rates of between about 1 and about 1,000 g / ha can be employed, with rates between 20 and about 500 g / ha being preferred. NTBC can be formulated in the same manner in which the herbicides are generally formulated. The object of the formulations is to apply the compositions to the site where control is desired by a convenient method. The "site" is intended to include soil, as well as established vegetation. In practice, NTBC is applied as a formulation containing various adjuvants and carriers known or used in the industry to facilitate dispersion. The choice of formulation and mode of application for NTBC can affect its activity, and the selection will be made accordingly. The NTBC can therefore be formulated as a wettable powder, as an emulsifiable concentrate, as granules, as a powder, as a fluid, in a controlled release form such as microcapsules, or as a solution, as a solution or as a suspension or emulsion. These formulations may contain as little as about 0.5% up to as much as about 95% or more by weight of NTBC. The optimal amount of NTBC will depend on the nature of the plants that will be controlled. Wettable powders are in the form of finely divided particles that readily disperse in water or other liquid carriers. The particles contain the active ingredient retained in a solid matrix or the active ingredient can be mixed with solid matrix particles. Normal solid matrices include fuller's earth, kaolin clays, silicas and other easily wettable organic and inorganic solids. Wettable powders typically contain about 5% about 95% of the active ingredient plus a small amount of wetting, dispersing or emulsifying agent. Emulsifiable concentrates are homogeneous liquid dispersible dispersions in water or another liquid, and may consist entirely of the active compound with a liquid or solid emulsifying agent or may also contain a liquid carrier, such as xylene, heavy aromatic naphthas, isophorone and other organic solvents non-volatile In use, these concentrates are dispersed in water or other liquid and are typically applied as a spray to the area to be treated. The amount of active ingredient may vary from about 0.5% to about 95% of the concentrate. Granular formulations include both extrudates and relatively coarse particles and are usually applied without dilution to the area in which vegetation suppression is desired. Typical carriers for granular formulations include sand, fuller earth, atapulquita clay, bentonite clays, montmorillonite clay, vermiculite, perlite and other organic or inorganic materials that absorb or can be coated with the active compound. Granular formulations typically contain about 5% about 25% active ingredients which may include surface active agents such as heavy aromatic naphthas, kerosene and other petroleum fractions or vegetable oils; and / or adherents such as dextrins, gum or synthetic resins. The powders are free-flowing mixtures of the active ingredient with finely divided solids such as talc, clays, flours and other organic and inorganic solids that act as dispersants and carriers. The fluids are creamy formulations that can be easily mixed with water to form a stable suspension. The flowable wettable powders, which are also referred to as flowable liquids or suspensions dispersible in water, consist of a wettable powder suspended in an oil or liquid base. The wettable powder in a fluid is usually finer milled than a regular wettable powder and therefore remains longer in suspension. The encapsulated microcapsules and granules are normal controlled release formulations. Typically the microcapsules are drops of the active material covered by an inert porous cover which allows the enclosed material to escape in the vicinity of controlled regimes, the encapsulated droplets typically being from about 1 to 50 microns in diameter. The enclosed liquid typically constitutes 50 to 95% by weight of the capsule and may include solvent in addition to the active compound. The encapsulated granules are generally porous granules with porous membranes that seal the pore openings of the granules, retaining the active species in liquid form within the granule pores. The granules typically vary from 1 millimeter to one centimeter, preferably from 1 to 2 millimeters in diameter. Granules typically vary from 1 millimeter to 1 centimeter, preferably 1 to 2 millimeters in diameter. The granules are formed by extrusion, agglomeration, or granulation or are present in nature. Examples of such materials are vermiculite, bonded clay, kaolin, attapulgite clay, sawdust and granulated carbon. The cover or membrane materials include natural and synthetic rubbers, cellulose materials, styrene-butadiene copolymers, polyacrylonitriles, polyacrylates, polyesters, polyamides, polyureas, polyurethanes and starch xantanes. Other useful formulations for herbicidal application include simple solutions of the active ingredient in a solvent which is completely soluble at the desired concentration such as acetone, alkylated naphthalenes, xylene and other organic solvents. Pressurized sprinklers, where the active ingredient is dispersed in a finely divided form as a result of atomization and vaporization of a low boiling point dispersing solvent carrier, can also be used. Suspensions and emulsions are additional useful formulations for herbicidal applications. In a suspension, particles of an immiscible solid or liquid active ingredient are dispersed in a liquid carrier, but do not dissolve therein. Usually an emulsion is a dispersion of fine particles of an oily active ingredient in water or, less commonly, as a dispersion of water droplets in an oily material. Many of these formulations include wetting, dispersing or emulsifying agents. Examples of these agents are alkyl and alkylaryl sulfonates and sulfates and their salts, polyhydric alcohols, polyethoxylated alcohols, esters and fatty amines. These agents, when used, typically comprise from 0.1% to 15% of the formulation.

Each of the above formulations can be prepared as a package containing the herbicide together with other ingredients of the formulation (diluents, emulsifiers, surfactants, etc.). The formulations can also be prepared by a tank mixing method wherein the ingredients are obtained separately and combined in a culture site. These formulations can be applied by conventional methods in areas where control is desired. The powder and liquid compositions, for example, can be applied by the use of powder spreaders, automatic and manual sprayers and spray coilers. The formulations can also be applied from airplanes as a powder or a sprayer or by wicking applications. To modify or control the growth of germinative seeds or emergent seedlings, the powder and liquid formulations can be distributed in the soil at a depth of at least one centimeter below the surface of the soil or can be applied to the soil surface only by spraying or sprinkling. The formulations can also be applied by the addition of irrigation water, allowing the penetration of the formulations in the soil together with the irrigation water. Powder compositions, granular compositions or liquid formulations applied to the surface of the soil may be distributed below the surface of the soil by conventional means such as cutting, tracking or mixing operations. EXAMPLES The following Examples are intended to further illustrate the present invention and are not intended to limit the scope of this invention in any way. The following examples are for illustrative purposes only and are not intended to be necessarily representative of the overall test performed and are not intended to limit the invention in any way. As one skilled in the material will know, in herbicide tests, a significant number of factors are not easily controllable, which can affect the results of individual tests and render them non-reproducible. For example, the results may vary depending on environmental factors, such as amount of sunlight and water, type of soil, soil pH, temperature and humidity, among other factors. Also the depth of the plantation and / or the regime of application of the herbicide, as well as the nature of the crops being tested may affect the results of the test. The results may vary from crop to crop within the crop varieties. TESTING OF HERBICIDE PRE-EMERGENCY SIZING One day after the treatment, the seeds of several species of different weeds and several species of crops were planted in sandy silt soil containing only trace organic matter. The propagules were planted in individual rows using one species per row across the width of an aluminum plane. The depths of the crop varied from 1.0 to 1.5 cm and the densities of the plant varied from 3 to 25 plants per row depending on the individual plant species. Weeds of planted grass were broadleaf (Bra chiaria platyphylla) "BRAPP": large bad grasses (Digi taria sanguinalis) "DIGSA"; boil de granaja: (Echinochl oa crusgalli) "ECHCG"; Rigid lolium (Lol i u m) "LOLRI", autumn millet (Panicum dichotomifl orum) "PANDI"; giant foxtail (Setari f aber i) "SETFA"; green fox tail (Setaria viridis) "SETAVI"; y yerba Jonson (Sorghuim halepense) "SORHA". The broad-leaved weeds planted were alcotán (Abutilón theophrast i) "ABUTH"; red root quenopodium (Amaran thus retroflexus) "AMARE", common mutton rooms (Chenopodium album) "CHEAL"; vine bell (Ipomoea hedera cea) "IPOHE"; common purslane (Portula ca oleceacea) "POROL"; and common hedgehog (Xan thium s t ruma r ium) "XANST". Additionally, yellow nutsedge (Cyperus esculentus) "CYPES" walnuts were also shown. The lands planted were Oryza sativa 'Katy' ("Rice"), Zea mays Garst 8532 '("Corn") and Glycine max' ICI 297 '("Soya"). The NTBC solutions were prepared by weighing an appropriate amount of the test compound to provide application rates of between 16 and 250 grams per hectare (g / ha) as indicated in Tables 1, 2 and 3 below, then dissolving the compound in a 50:50 mixture of deionized water and acetone containing 0.5% v / v of Tween 20 (R | (polyoxyethylene sorbitan monolaurate emulsifier) as a surfactant.Additional solvents, not exceeding 15% spray volume, were used if necessary to dissolve the compound.The floor surface was sprayed inside a linear spray table in closed with the nozzle capped above the floor line.The spray table was calibrated to supply 400 L / ha with the application regime being between 16 and 250 g / ha as indicated.After the treatment, the laying was placed in a greenhouse and water was administered as necessary. However, they provided the plants with natural and artificial lighting to obtain 14 hours of light per day. The day and night temperatures were maintained at 29 ° and 21 ° C respectively. The degree of grass control was evaluated and recorded 23 days after treatment as a percentage of grass control compared to the growth of the same species of the same age in an untreated control line. The percent control is the total damage of the plants due to all factors including: inhibited emergence, growth impediment, malformation, chlorosis and other types of damage to plants. The results of the screening tests prior to emergence are shown in Tables 1, 2 and 3 below. The control regimes vary from 0 to 100 percent, where 0 represents no effect with growth equal to the untreated control and where 100 represents complete death.

TABLE 1 - Pre-emergence Screening (Grass Weed) REGIME (WEIGHT CONTROL (Percentage) (g / ha) BRAPP DIGSA ECHCG LOLRI PANDI SETFA SETVI SORHA 16 90 100 100 30 100 100 90 90 63 100 100 100 65 100 100 100 100 125 100 100 100 60 100 100 100 100 250 100 100 100 90 100 100 100 100 TABLE 2- Pre-emergence screening (Broadleaf weed and nutlet sedge) REGIME (WEIGHT CONTROL (Percentage) (g / ha) ABUTH AMARE CHEAL IPOHE POROL XANST CYPES 16 100 100 100 35 100 25 80 63 100 100 100 65 100 70 90 125 100 100 100 100 100 90"90 250 100 100 100 100 100 100- 90 TABLE 3 - Preemergence Screening CULTURE DAMAGE SCHEME (Percentage) (g / ha) RICE MAIZE SOY 16 98 0 65 63 100 0 80 125 100 15 90 250 100 45 95 TESTING OF HERBICIDE POST-EMERGENCY TEST The soil was prepared and planted with the same species (except P1GSA) and methodology] > to ? The preemergence test. The preemergence layouts were placed in the greenhouse under the same environmental conditions as described for the preemergence layouts and water was given as needed. The plants were grown for 12 days (or the appropriate growth stage) before the application of the compound. The grasses were sprayed in a stage of 3 to 4 leaves and width of leaves in a stage of 1 to 2 leaves. The yellowish sedges were 5 to 7 cm high in the application. The plants were sprayed 30.5 cm (12 inches) above the foliage with the same spray solution prepared for the preemergence test. The application regime was indicated in Tables 4,5 and 6 below. The treated plants were returned to a greenhouse and water was given daily without wetting the foliage. The degree of weed control was evaluated at 22 days after application and was recorded, percentage of control compared to the growth of the same species in an untreated control line. The percentage control scale (0-100?) Used to evaluate preemergence treatment was also applied to post-emergency treatment. s postemergence screening test results ee shown in the following Tables 4, 5 and 6. TABLE 4 - Post-Agressive Screening (Grass Weed) REGIME (WEIGHT CONTROL (Percentage) (g / ha) BRAPP ECHCG LOLRI PANDI SETFA SETVI. SORHA 16 15 50 0 50 40 15 10 63 55 75 10 70 50 60 35 125 90 80 25 85 60 60 35 250 90 90 45 90 88 88 75 TABLE 5 - Post-Emergence Screening (Broadleaf Weed and Nut Seed) REGIME (WEIGHT CONTROL (Percentage) (g ha) ABUTH AMARE CHEAL IPOHE POROL XANST CYPES 16 100 70 100 60 100 35 50 63 100 95 100 75 100 80 80 125 100 95 100 98 100 85 80 250 100 98 100 95 100 85 85 TABLE 6 - Preemergence Screening CROP DAMAGE REGIME (Percentage) (g / ha) RICE MAIZE SOY 16 0 5 65 63 35 20 70 125 45 0 70 250 70 8 85 The results shown in tables 1-6 illustrate the effectiveness of NTBC herbicide against a broad spectrum of broadleaf grass and weed species, as well as the selectivity of NTBC with respect to corn. Although the invention has been described with reference to the preferred embodiments and examples thereof, the scope of the present invention is not limited solely to the embodiments described. As will be apparent to persons skilled in the art, modifications and adaptations may be made to the invention described above without departing from the spirit and scope of the invention, which is defined and circumscribed by the appended claims.

Claims (5)

1. ] 7 CLAIMS 1. A method for selectively controlling undesirable vegeta- tion in corn, characterized in that it comprises | j |, | jca)? A herbicidally elective eunity of _ '' - (? '- ni ti o-4' - 1] i 11 ii i op? c-1 j)? IIZOÍI) -1, 3-cyclohexanedi on, and an agriculturally acceptable salt thereof, to the site of said vegetation.
2. 2. The method of compliance with the claim 1, characterized in that 2- (2'-nitro-4'-trifluoromethylbenzoyl) -1,3-cyclohexanedione is applied at a rate of between about 1 and about 1000 grams per hectare.
3. 3. The method of compliance with the claim 2, characterized in that 2- (2'-nitro-4'-trifluoromethylbenzoyl) -], 3-cyclohexanedione are applied between about 20 and about 500 grams per hectare. . .
4. The method according to claim 1, characterized in that 2- (2'-nitro-4'-trifluoromethylbenzoyl) -1,3-hexahexanodione preemergence is applied.
5. 5. The method of compliance with the claim J, characterized in that postemergence is applied.