WO2019209847A1

WO2019209847A1 - Compositions and methods for controlling undesirable vegetation in crops

Info

Publication number: WO2019209847A1
Application number: PCT/US2019/028752
Authority: WO
Inventors: Honwu HUANG; Demin SONG; Cong CONG; Youggui KU; Chungeng NI; Hao Long; Zengliang LI
Original assignee: FMC Corp
Current assignee: FMC Corp
Priority date: 2018-04-24
Filing date: 2019-04-23
Publication date: 2019-10-31
Anticipated expiration: 2020-10-24
Also published as: AR114836A1; CN112165862B; WO2019209847A8; CN112165862A

Abstract

The present disclosure relates to herbicidal compositions comprising a first herbicide selected from the group consisting of 2,4-DC, 2,5-DC and mixtures thereof, and a second herbicide that is isoproturon; and methods for controlling undesirable vegetation in crops comprising applying a combination of the first herbicide and the second herbicide to the locus of the vegetation.

Description

COMPOSITIONS AND METHODS FOR CONTROLLING UNDESIRABLE

VEGETATION IN CROPS

TECHNICAL FIELD

The present disclosure relates to herbicidal compositions and methods for controlling undesirable vegetation in crops.

BACKGROUND

One recurring challenge in agriculture involves controlling growth of undesirable vegetation which can interfere with crop growth and reduce crop yield. To combat that challenge, many chemicals and formulations have been developed and employed in the agriculture industry.

United States Patent 4,405,357 discloses certain 3-isoxazolidinones which exhibit desirable selective herbicidal activity. Specifically, such compounds are shown to be effective in controlling grassy and broadleaf weed species while leaving legumes, particularly soybeans, unaffected. Among the compounds specifically disclosed in this patent are 2-[(2,4-dichlorophenyl)methyl]-4,4- dimethyl-3-isoxazolidinone (CA No. 81777-95-9) and 2-[(2,5- dichlorophenyl)methyl]-4,4-dimethyl-3-isoxazolidinone (CA No. 81778-66-7). Both such compounds are effective against a number of weeds.

In crop protection products, it is always desirable to increase the specific activity of active ingredients, provide resistance management, or broaden the scope of activity to include, for herbicidal compositions, control of additional weed species. Mixtures of crop protection agents are often used to provide such improved activity.

BRIEF SUMMARY OF THE INVENTION

Surprisingly, it now has been found that combinations of certain 3- isoxazolidinones and isoproturon exhibit a synergistic effect when used for controlling undesirable vegetation.

In one aspect, the present invention is directed to a herbicidal composition comprising a first herbicide selected from the group consisting of 2-(2,4- dichlorophenyl)methyl-4,4-dimethyl-3-isoxazolidone (“2,4-DC”), 2-(2,5- dichlorophenyl)methyl-4,4-dimethyl-3-isoxazolidone (“2,5-DC”) and mixtures thereof; and a second herbicide that is isoproturon. In another aspect, the present invention is directed to a method of controlling undesirable vegetation in a crop comprising applying to the locus of such vegetation an herbicidally-effective amount of a combination comprising a first herbicide selected from the group consisting of 2,4-DC, 2,5-DC and mixtures thereof, and a second herbicide that is isoproturon.

In a specific aspect, the present invention relates to a method for controlling undesirable vegetation in a crop comprising applying to the locus of such vegetation an herbicidally-effective amount of a combination comprising a first herbicide that is 2,4-DC and a second herbicide that is isoproturon, wherein said undesirable vegetation includes at least one of Alopecurus aequalis sobol (short-awn foxtail) and Sclerochloa dura (L.) P. Beauv (hardgrass, tufted hardgrass), and the crop is wheat.

DETAILED DESCRIPTION

The term“and/or” means any one of the items, any combination of the items, or all of the items with which this term is associated. The singular forms“a,”“an,” and “the” include plural reference unless the context clearly dictates otherwise. Accordingly, the indefinite articles“a” or“an”, as used in the claims, are defined herein to mean one or more than one of the element that it introduces. Thus, for example, a reference to“a compound” includes a plurality of such compounds, so that a compound X includes a plurality of compounds X. It is further noted that the claims may be drafted to exclude any optional element, i.e. an optional element may or may not be present in the claimed embodiment. As such, this statement is intended to serve as antecedent basis for use of such exclusive terminology as“solely,”“only,” and the like in connection with the recitation of claim elements, or use of a“negative” limitation.

Whenever a numerical range with a lower limit and an upper limit is disclosed, any number and any included range falling within the range is specifically disclosed. In particular, every range of values (of the form,“from about a to about b,” or, equivalently,“from approximately a to b,” or, equivalently,“from approximately a— b”) disclosed herein is to be understood to set forth every number and range encompassed within the broader range of values. When ranges are expressed as ranging from one or more lower limit(s) to one or more upper limit(s), ranges comtemplated may range from any of the enumerated lower limits to any of the enumerated upper limits.

While compositions and methods are described in terms of “comprising,” “containing,” or“including” various components or steps, the compositions and methods can also“consist essentially of’ or“consist of’ the various components and steps. All numbers and ranges disclosed above may vary by some amount. Also, the terms in the claims have their plain, ordinary meaning unless otherwise explicitly and clearly defined herein. If there is any conflict in the usages of a word or term in this specification and one or more patent or other documents that may be incorporated herein by reference, the definitions that are consistent with this specification should be adopted.

As used in this application and unless otherwise indicated the term “herbicide” refers to a composition mixture that is produced, sold, or used in a field in order to kill or otherwise inhibit the growth of unwanted plants such as, but not limited to, deleterious or annoying weeds, broadleaf plants, grasses, and sedges; and can be used for crop protection, edifice protection or turf protection. The term“herbicide” includes the end-use herbicidal product. This composition can be a pure compound, a solution of chemical compounds, a mixture of chemical compounds, an emulsion, a suspension, a solid-liquid mixture, or a liquid-liquid mixture.

The term“herbicide” also refers to the product that passes through the commercial channels from the manufacturer to the ultimate end user who can either apply the herbicide to the affected field as sold, or mix it with other excipients.

The term“weed” means and includes any plant that grows where not wanted.

The term “herbicidally-effective amount” means an amount of the composition or of the combinations according to the invention necessary to produce an observable herbicidal effect on unwanted plant growth, including one or more of the effects of necrosis, death, growth inhibition, reproduction inhibition, inhibition of proliferation, and removal, destruction, or otherwise diminishing the occurrence and activity of unwanted plants.

The term“herbicidally active ingredient(s)” refers to active ingredient(s) in the herbicide that causes the herbicide to prevent, destroy, repel or mitigate any weed. Other ingredients of the herbicide that are not herbicidally active ingredients are excipients that aid in forming, storing, or delivering a herbicidally active ingredient to the target. The term“herbicidal composition” refers to an herbicide, and in addition, to any composition that comprises an herbicidally active ingredient, such as those described herein, and optionally including at least one excipient. This composition can be a solution or a mixture. Further, the term “herbicidal composition” also refers to a product intended for use in manufacturing, or any product intended for formulation or repackaging into other agricultural products. The composition includes any of the formulation types described below and also includes one or more formulations comprising the herbicidally active ingredients mixed with a diluent prior to application to the plants.

The term “2,4-DC” refers to 2-[(2,4-dichlorophenyl)methyl]-4,4- dimethyl-3-isoxazolidinone.

The term “2,5-DC” refers to 2-[(2,5-dichlorophenyl)methyl]-4,4- dimethyl-3-isoxazolidinone.

The term“isoproturon” refers to 3-(4-isopropylphenyl)-l,l-dimethylurea (i.e. L A -dimethyl-/V'-[4-(l-methylethyl)phenyl]urea (CA No. 34123-59-6)) .

At least one aspect of the present invention is directed to a herbicidal composition or combination comprising a first herbicide selected from the group consisting of 2,4-DC, 2,5-DC and mixtures thereof; and a second herbicide that is isoproturon. In one embodiment, the first herbicide is 2,4-DC. In another embodiment, the first herbicide is a mixture of 2,4-DC and 2,5-DC. If a mixture of 2,4-DC and 2,5-DC is employed, 2,4-DC and 2,5-DC can be present in any ratios. In a specific embodiment, 2,4-DC is present in excess of 2,5-DC.

The second herbicide in the composition or combination is isoproturon. It is a photosystem II photosynthesis inhibitor.

In another embodiment, the compositions of the present invention can further contain a third herbicide. As used in the present invention, the third herbicide does not interfere with the synergistic effect between the first herbicide and the second herbicide. A third herbicide may be utilized if broadening of the spectrum of weed control or preventing the occurrence of resistance is desirable. Example of useful additional herbicides include but are not limited to acetochlor, aclonifen, ametryn, amicarbazone, atrazine, bispyribac, beflubutamid, S- beflubutamid, bromoxynil, carfentrazone, carfentrazone ethyl, cyhalofop, 2,4-D, 2,4-DB, 2,4-DEB, dicamba, diflufenican, dimethachlor, dimethenamid-P, ethalfluralin, ethoxysulfuron, flucetosulfuron, fluthiacet-methyl, fomesafen, hexazinone, isoxaflutole, linuron, mesotrione, metamifop, metazachlor, metobromuron, S-metolachlor, metribuzin, metsulfuron, metsufluron-methyl, napropamide, pendimethalin, pethoxamid, pretilachlor, propanil, pyroxasulfone, quizalofop, tebuthiuron, thifensulfuron, thifensulfuron-methyl, sulfentrazone, trifluralin, agriculturally acceptable salts thereof, esters thereof and mixtures of two or more thereof.

In yet another embodiment, said third herbicide is selected from the group consisting of napropamide, aclonifen, pyroxasulfone, metazachlor, diflufenican, sulfentrazone, mesotrione, metsulfuron, thifensulfuron, thifensulfuron-methyl and agriculturally acceptable salts thereof, esters thereof and mixtures of two or more thereof. In another embodiment, the composition of the invention can also include a herbicide safener selected from the group consisting of allidochlor, benoxacor, cloquintocet-mexyl, cumyluron, cyometrinil, cyprosulfonamide, daimuron, dichlormid, dicyclonon, dietholate, dimepiperate, fenchlorazole-ethyl, fenclorim, flurazole, fluxofenim, furilazole, isoxadifen-ethyl, mefenpyr-diethyl, mephenate, methoxyphenone naphthalic anhydride (l,8-naphthalic anhydride), oxabetrinil, N-(aminocarbonyl)-2-methylbenzenesulfonamide, N-(aminocarbonyl)-2 fluorobenzenesulfonamide, 1 -bromo-4- [(chloro-methyl)-sulfonyl] -"benzene

(BCS), 4-(dichloroacetyl)-l-oxa-4 azospiro[4.5]decane (MON 4660), 2-

(dichloromethyl)-2 methyl- 1, 3 -dioxolane (MG 191), ethyl l,6-dihydro-l-(2- methoxyphenyl)-6-oxo-2-phenyl-5-pyrimidinecarboxylate, 2 hydroxy-N,N- dimethyl-6-(trifluoromethyl)pyridine-3-carboxamide, 3 oxo-l-cyclohexen-l-yl 1- (3,4-dimethylphenyl)-l,6-dihydro-6-oxo-2-phenyl-5-pyrimidinecarboxylate, 2,2- dichloro-l-(2,2,5-trimethyl-3-oxazolidinyl)-ethanone and 2-methoxy-N-[[4- [[(methylamino)carbonyl]amino]phenyl]sulfonyl]-benzamide to increase safety to certain crops. Of note is a composition of the invention including cloquintocet-mexyl or mefenpyr-diethyl. Of note is a composition of the invention including cloquintocet-mexyl.

In another aspect, the present invention relates to a method of controlling undesirable vegetation in a crop comprising applying to the locus of such vegetation a combination comprising a first herbicide selected from the group consisting of 2,4-DC, 2,5-DC and mixtures thereof; and a second herbicide that is isoproturon. As discussed further below, the combination can be applied as a single composition, or as separate compositions.

In one embodiment, said undesirable vegetation includes at least one selected from the group consisting of grass weeds and broadleaf weeds. In another embodiment, said vegetation is selected from the group consisting of annual bluegrass, Benghal dayflower, blackgrass ( Alopecurus myosuroides), black nightshade, broadleaf signal grass, Canada thistle, cheat, common cocklebur (Xanthium pensylvanicum), common ragweed, corn poppies, field violet, giant foxtail, goosegrass, green foxtail, guinea grass, hairy beggarticks, herbicide- resistant blackgrass, horseweed, Italian rye grass, jimsonweed, Johnson grass (Sorghum halepense), large crabgrass, little seed canary grass, morning glory, Pennsylvania smartweed, pitted morning glory, prickly sida, quackgrass, redroot pigweed, shattercane, shepherd’s purse, silky windgrass, sunflower (as a weed in potato crops), wild buckwheat (Polygonum convolvulus), wild mustard (Brassica kaber), wild oat (Avena fatua), wild pointsettia, yellow foxtail, yellow nutsedge (Cyperus esculentus), Alopecurus japonicus, Myosoton aquaticum, Stellaria media, and Beckmannia syzigachne. In a preferred embodiment, said undesirable vegetation includes at least one of Alopecurus aequalis sobol, Sclerochloa dura (L.) P. Beauv. Alopecurus japonicus, Myosoton aquaticum, Stellaria media, Beckmannia, and syzigachne. In another preferred embodiment, said undesirable vegetation includes at least one of Alopecurus aequalis sobol, Sclerochloa dura (L.) P. Beauv., Alopecurus japonicus, Myosoton aquaticum, Stellaria media, and Beckmannia syzigachne that is growing in wheat ( Triticum aestivum).

In yet another embodiment, the crop is selected from the group consisting of broadleaf crops and grass. In a preferred embodiment, the crop includes bananas, beans, beets, cassava, cereals, citrus, cocoas, coconuts, coffee, corn, cotton, fiber crops, flowers, forage corps, forestry, groundnuts, peanuts, hops, horticultures, non-land crops, oil palm, oilseed rape, peas, pomes, potato, rice, stonefruit, spices, sugar cane, sunflower, tea, tobacco, tomatoes, tree nuts, turf, vegetable crops, vines, and grapes. In at least one embodiment, the crops are potato, soybean, corn, rice, sorghum, oilseed rape, barley, rye, cowpea or canola. In a more preferred embodiment, the crop is wheat.

In a specific aspect, the present invention relates to a method of controlling undesirable vegetation in a crop, comprising applying to the locus of such vegetation a combination comprising a first herbicide selected from the group consisting of 2,4-DC, 2,5-DC and mixtures thereof; and a second herbicide that is isoproturon, wherein said vegetation includes at least one of Alopecurus aequalis sobol and Sclerochloa dura (L.) P. Beauv, and the crop is wheat.

The compositions containing the active compounds/ingredients of the present invention may be employed in any conventional agriculturally useful form, for example, in the form of a twin pack, or in a ready-to-use formulation, or in the form of a tank mix. Additionally, the active compounds can be supplied (either separately or pre-mixed) in any appropriate formulation type, for example an emulsifiable concentrate (EC), a suspension concentrate (SC), a suspo- emulsion (SE), a capsule suspension (CS), a water dispersible granule (WG), an emulsifiable granule (EG), a water in oil emulsion (EO), and oil in water emulsion (EW), an oil dispersion (OD), an oil miscible flowable (OF), an oil miscible liquid (OL), a soluble concentrate (SL), an ultra-low volume suspension (SU), an ultra- low volume liquid (UL), a dispersible concentrate (DC), a wettable powder (WP) or any other technically feasible formulation. Such compositions can be formulated using excipients and formulation techniques that are known in the art for individually formulating the herbicides. For example, the herbicides may be mixed together, optionally with other formulating ingredients. The active ingredients of the compositions may be provided in a single formulation, or in tank-mix form where the active ingredients are each provided in a separate formulation that are tank mixed, typically with a diluent such as water, prior to application. The active ingredients are preferably co-formulated and provided in a single formulation to provide a more convenient application, and more preferably provided in a formulation type, for instance, WP, WG, SC, EC, or CS formulation.

The active ingredients of the compositions may be encapsulated or non- encapsulated. Encapsulation is usually used to reduce the volatility of the herbicide or provide slow release of the herbicide. In a specific embodiment, the first herbicide of the compositions is encapsulated (e.g. encapsulation of 2,4-DC, 2,5-DC or both), with the second herbicide being non-encapsulated.

When mixed with additional components, the compositions typically contain about 0.01 to about 95% by weight of active compounds, while the rest typically are excipients for formulating the herbicides, for instance diluents, surfactants and the like.

The term diluent includes all liquid and solid agriculturally acceptable material including carriers which may be added to the herbicides to bring them in a suitable application or commercial form and include solvents, emulsifiers, and dispersants. The diluent may be added during the formulation process, after the formulation process (e.g. by the user - a farmer or custom applicator), or both. Examples of suitable solid diluents or carriers are aluminum silicate, talc, calcined magnesia, kieselguhr, tricalcium phosphate, powdered cork, absorbent carbon black, chalk, silica, and clays such as kaolin and bentonite. Examples of suitable liquid diluents include water, organic solvents (e.g. acetophenone, cyclohexanone, isophorone, toluene, xylene, petroleum distillates), amines (e.g. ethanolamine, dimethylformamide), and mineral, animal, and vegetable oils (used alone or in combination).

The compositions may also contain surfactants, protective colloids, thickeners, penetrating agents, stabilizers, sequestering agents, anti-caking agents, coloring agents, corrosion inhibitors, and dispersants such as lignosulfite waste liquors and methylcellulose. The term surfactant, as used herein, means an agriculturally acceptable material which imparts emulsifiability, stability, spreading, wetting, dispersibility or other surface-modifying properties. Examples of suitable surfactants include lignin sulfonates, fatty acid sulfonates (e.g. lauryl sulfonate), the condensation product of formaldehyde with naphthalene sulfonate, alkylarylsulfonates, ethoxylated alkylphenols, and ethoxylated fatty alcohols. Other known surfactants that have been used with herbicides are also acceptable.

The compositions may be applied in various combinations of the active ingredients. For example, they may be applied as a single“ready-mix” form, or in a tank mix form. Thus, to be used in combination, it is not necessary that the active ingredients are applied in a physically combined form, or even at the same time. In other word, the active ingredients may be applied separately and/or sequentially, provided that the application of the second active compound occurs within a reasonable period of the time from the application of the first active compound, such as within 24 hours, or 48 hours. The compositions may be applied post-emergence. In a preferred embodiment, the compositions are applied early post-emergence. In a specific embodiment, the compositions of the present invention are applied to protect wheat at the four-leaf stage of wheat.

Rates of the application of the composition will vary according to a number of factors such as targeted weeds, degree of infestation, weather conditions, soil conditions, crop species, mode of application, and time of application.

The weight ratio of the first herbicide and the second herbicide is preferably selected to provide synergistic weed control. Such amounts are also called synergistically effect amounts and can easily be determined by the skilled person using well known principles. In general, the weight ratio of the first herbicide (for instance, 2,4-DC or 2,5-DC) and the second herbicide (i.e., isoproturon) ranges from 1: 1 to 1:20, 1 : 1 to 1 : 15, or 1: 1 to 1: 10.

An effective amount of the combination of the first herbicide and the second herbicide is any amount that has the ability to combat the undesirable vegetation. In general, the first herbicide (for instance, 2,4-DC or 2,5-DC) is employed in an amount from a lower limit of 50 g a.i./ha to an upper limit of 200, 500 or 1,000 g a.i./ha, preferably from 50 to 500 g a.i./ha, such as from 75 grams to 125 g a.i./ha; and the second herbicide (i.e., isoproturon) is employed in an amount from a lower limit of 1,500 or 1,000 g a.i./ha to an upper limit of 2,000, 2,500 or 4,000 g a.i./ha, preferably from 500 to 2,500 g a.i./ha, such as from 750 to 1,125 g a.i./ha. However, higher and in particular lower doses may also provide adequate control.

An additional herbicide may be also used, provided that the additional herbicide does not interfere with the synergistic effect between the first herbicide and the second herbicide. An additional herbicide may be utilized if broadening the spectrum of control or preventing the build-up of resistance is desired. Examples of additional herbicides useful in the present invention include but are not limited to those discussed above.

Synergy was calculated using the method of Colby. As used herein, the terms“synergy” and“synergistic”, or the phrase“in a synergistic manner”, refer to the in vivo interaction of two or more biologically active compounds, in the present case the first herbicide with the second herbicide, so that their combined effect when administered together is greater than the sum of the effects observed when each is administered individually. In this way the applied rate of the herbicidal combination can be lower than the registered use rates, thereby reducing the total chemical burden on the field to which such a combination is applied.

The method of Colby for determining synergism is described in Colby, S.R., “Calculating Synergistic and Antagonistic Responses of Herbicide Combinations”, Weeds 1967, 15, p 20-22, which is incorporated herein by reference. According to this methodology, the presence of a synergistic effect between the two active ingredients is established with the aid of the Colby equation: E=X+Y-(XY/l00). Using the method of Colby, the presence of a synergistic interaction between two active ingredients is established by first calculating the expected activity, Έ’, of the mixture based on activities of the two components applied alone. In the equation above, ‘X’ is the herbicidal activity in percentage control of the disclosed 3- isoxazolidinone applied as a mixture at rate‘x’. The Ύ term is the herbicidal activity of the second active (isoproturon) applied as a mixture at rate‘y’. The equation calculates Έ’, the “expected” herbicidal activity of the mixture of ‘X’ at rate‘x’ with‘Y’ at rate ‘y’. If Έ’ is lower than the observed activity, synergy is present. If the herbicidal effect is strictly additive and no interaction has occurred, Έ’ will be equal to or higher than the observed activity.

The following Tables in the Examples below summarize the % control of the test weed species and the expected value verses observed % control of mixtures of a 3 -isoxazolidinone compound tested alone or in combination with isoproturon in field trials.

The invention is illustrated by the following examples.

SYNTHESIS EXAMPLE 1

Preparation of 2-(2,4-dichlorobenzyl)-4,4-dimethylisoxazolidin-3-one (2,4-DC) Step A: Preparation of 4,4-dimethylisoxazolidin-3-one sodium salt (CAS No.

107746-05-4) To 4,4-dimethyl-3-isoxazolidinone (CAS No. 81778-07-6) was added to water followed by the addition of aqueous sodium hydroxide to form a solution with a pH of 9.5 to 9.7. The resulting salt solution was used directly in the next step.

Step B: Preparation of 2-(2,4-dichlorobenzyl)-4,4-dimethylisoxazolidin-3-one

To the aqueous solution of 4,4-dimethylisoxazolidin-3-one sodium salt was added tetrabutyl ammonium bromide in catalytic amounts and the solution was heated to 50-60°C. 2,4-Dichlorobenzyl chloride was added as such a rate to maintain the reaction temperature between 50-60 °C for 30 min to lh. The reaction mass was seeded with previously preapared product and the reaction continued until all of the 2,4- dichlorobenzyl chloride was consumed. The resulting slurry was cooled to ambient temperature and filtered. The resulting solids were washed once with water, twice with heptanes and again with water, then dried at around 50 °C (yields from 75% to 77%). The heptane washes were combined to recover unreacted 4,4-dimethylisoxazolidin- 3-one sodium salt, 2,4-dichlorobenzyl chloride and (9-alkylated side product (i.e. 3-[(2,4-dichlorophenyl)methoxy]-4,5-dihydro-4,4-dimethylisoxazole).

Step C: Preparation of 2-(2,4-dichlorobenzyl)-4,4-dimethylisoxazolidin-3-one

To the combined heptane washes obtained in Step B (i.e. containing unreacted 4,4-dimethylisoxazolidin-3-one sodium salt, 2,4-dichlorobenzyl chloride and (9-alkylated side product, 3-[(2,4-dichlorophenyl)methoxy]-4,5-dihydro-4,4- dimethylisoxazole)) was added methanol and the solution was heated to 40°C. Dry HC1 gas was passed through the solution while maintaining the temperature between 40- 45 °C for 1.5 h. The reaction was held at 40 °C for 4-6 h. The two layers of the reaction were separated and the bottom (aqueous) layer was back-washed with heptanes. The combined heptanes layers were distilled to yield 2,4-dichlorobenzyl chloride along with trace amounts of 2-(2,4-dichlorobenzyl)-4,4-dimethylisoxazolidin-3-one and 4,4-dimethylisoxazolidin-3-one (CAS No. 81778-07-6) which were used directly in subsequent batches of Step A. The bottom (aqueous) layer was treated with 10% sodium hydroxide to provide 4,4-dimethylisoxazolidin-3-one sodium salt, which were used directly in subsequent batches of Step A.

Biological Example: Post-Emergence Herbicidal Efficacy Evaluation

Preparation of the compositions for testing

An SC formulation of 2,4-DC was prepared by combining 44.0% 2,4-DC, 1.5% TERGITOL™ XD (Dow Chemical Company), ETHOX ERS 01293 (Ethox Chemicals), 6.0% propyleneglycol, 0.13% of a 2% aqueous solution of KELZAN^® M xanthan gum (CPKelco A Huber Company), 0.15% DOW AF antifoam (Dow Chemical Company) and 46.7% water (all % by weight) and milling the mixture until a particle size of D90 (90% of the particles have a diameter) less than about 50 microns was obtained.

A 50% WP formulation of isoproturon was obtained from the marketplace (Registration No. PD20040658, Jiangsu Kuaida Agrochemical Co., Ltd.).

Mixtures of 2,4-DC and isoproturon were provided in a tank-mix form by mixing the SC formulation of 2,4-DC and the 50% WP formulation of isoproturon prior to use.

Efficacy testing

The compositions described above were tested for herbicidal efficacy. The test crop was wheat, and the test weeds were Alopecurus aequalis sobol and Sclerochloa dura (L.) P. Beauv. For the post-emergence test, wheat was planted in a field with the targeted weeds naturally occurring and well watered before the application of the compositions. The test compositions were applied by spray application individually and in combination at the rates indicated at the four-leaf stage of wheat, and the control of weeds was assessed at a certain day after treatment (DAT) as indicated in Tables 1 and 2 below.

Control Observed (%) is calculated by the following formula: 100

wherein X_g and Xi is the number of weeds pre-treatment and post- treatment in a same area, respectively

Table 1: Control against Alopecurus aequalis sobol in wheat

Control Observed Expected Control

No. Treatment g a.i./ha

(42 DAT)% (Colby method) %

1 2,4-DC 75 5.09

2 2,4-DC 100 18.27

3 2,4-DC 125 31.45

4 2,4-DC+Isoproturon 75+1125 96.30 90.24

5 2,4-DC+Isoproturon 100+1125 96.78 91.60

6 2,4-DC+Isoproturon 125+750 96.86 81.95

7 2,4-DC+Isoproturon 125+1125 96.78 92.95

8 Isoproturon 750 73.67

9 Isoproturon 1125 89.72 Table 2: Control against Sclerochloa dura (L.) P. Beauv in wheat

. .„ Control Observed Expected Control

No. Treatment g a.i./ha ,„_{n A M} ,, ,, ,

° (63 DAT)% (Colby method) %

1 2,4-DC 75 37.25

2 2,4-DC 100 37.92

3 2,4-DC 125 42.74

5 2,4-DC+Isoproturon 75+1125 87.53 87.01

6 2,4-DC+Isoproturon 100+1125 90.95 87.15

7 2,4-DC+Isoproturon 125+750 89.24 88.04

8 2,4-DC+Isoproturon 125+1125 93.78 88.15

9 Isoproturon 750 79.11

10 Isoproturon 1125 79.31

As clearly shown in Tables 1 and 2, combinations of 2,4-DC and isoproturon demonstrated synergistic weed control, with higher measured weed control than predicted by the Colby formula.

The present disclosure is well adapted to attain the ends and advantages mentioned as well as those that are inherent therein. The particular embodiments disclosed above are illustrative only, as the present disclosure may be modified and practiced in different but equivalent manners apparent to those skilled in the art having the benefit of the teachings herein. Features of the disclosed embodiments may be combined, rearranged, omitted, etc., within the scope of the invention to produce additional embodiments. Furthermore, certain features may sometimes be used to advantage without a corresponding use of other features. Furthermore, no limitations are intended to the details of construction or design herein shown, other than as described in the claims below. It is therefore evident that the particular illustrative embodiments disclosed above may be altered or modified and all such variations are considered within the scope and spirit of this invention.

Claims

1. A herbicidal composition comprising a first herbicide selected from the group consisting of 2,4-DC, 2,5-DC and mixtures thereof; and a second herbicide that is isoproturon.

2. The composition according to claim 1, wherein the first herbicide is 2,4-DC.

3. The composition according to claim 1 or claim 2, wherein the weight ratio of the first herbicide to the second herbicide ranges from about 1 : 1 to about 1 :20.

4. The composition according to claim 1 or claim 2, wherein the first herbicide and the second herbicide are present in a form of a pre-mix or a tank-mix.

5. A method for controlling undesirable vegetation in a crop comprising applying to the locus of the undesirable vegetation an herbicidally-effective amount of a combination comprising a first herbicide and a second herbicide, wherein the first herbicide is selected from the group consisting of 2,4-DC, 2,5-DC and mixture thereof, and the second herbicide is isoproturon.

6. The method according to claim 5, wherein the first herbicide is 2,4-DC.

7. The method according to claim 5, wherein said undesirable vegetation includes at least one selected from grass weeds and broadleaf weeds.

8. The method according to claim 7, wherein said undesirable vegetation includes at least one of Alopecurus aequalis sobol, Sclerochloa dura (L.) P. Beauv, Alopecurus japonicus, Myosoton aquaticum, Stellaria media, and Beckmannia syzigachne.

9. The method according to claim 5, wherein said crop is selected from the group consisting of broadleaf crops and grass crops.

10. The method according to claim 9, wherein said crop is selected from the group consisting of bananas, beans, beets, cassava, cereals, citrus, cocoas, coconuts, coffee, corn, fiber crops, flowers, forestry, forge corps, grapes, groundnuts, hops, horticultures, non-land crops, oil palm, oilseed rape, peas, peanuts, pomes, potato, rice, spices, stonefruit, sugar cane, sunflower, tea, tobacco, tree nuts, turf, vegetable crops, vines, and wheat.

11. The method according to claim 5, wherein the combination is applied post-emergence.

12. The method according to claim 5, wherein the combination is applied early post-emergence.

13. The method according to claim 5, wherein the combination is applied as a composition in a form of pre-mix or tank-mix.

14. The method according to claim 13, wherein the composition is applied through spraying application.

15. The method according to claim 5, wherein the weight ratio of the first herbicide to the second herbicide is from 1: 1 to 1:20.

16. The method according to claim 5, wherein the first herbicide is applied in an amount from 50 to 1,000 g a.i./ha, and the second herbicide is applied in an amount from 1 to 4,000 g a.i./ha.

17. The method according to claim 16, wherein the first herbicide is applied in an amount from 100 to 500 g a.i./ha, and the second herbicide is applied in an amount from 1,000 to 2,000 g a.i./ha.

18. The method according to claim 5 wherein the crop is wheat, and the undesirable vegetation includes at least one of Alopecurus aequalis sobol, Sclerochloa dura (L.) P. Beauv, Alopecurus japonicus, Myosoton aquaticum, Stellaria media, and Beckmannia syzigachne.