WO1997007678A1

WO1997007678A1 - Herbicidal mixtures for paddy fields

Info

Publication number: WO1997007678A1
Application number: PCT/US1996/013581
Authority: WO
Inventors: Shinichi Shirakura
Original assignee: E.I. Du Pont De Nemours And Company
Priority date: 1995-08-31
Filing date: 1996-08-21
Publication date: 1997-03-06
Also published as: TW348053B; AU6956796A; JPH09124419A

Abstract

This invention relates to herbicidal mixtures of azimsulfuron with dimepiperate optionally containing also bensulfuron methyl, herbicidal compositions of said mixtures, and a method for the use of said mixtures to control undesired vegetation.

Description

TTTLE HERBICIDAL MIXTURES FOR PADDY FIELDS

FIELD OF THE INVENTION The present invention relates to mixtures of herbicides that not only provide surprisingly excellent weed control but also have a safening effect on rice.

BACKGROUND OF THE INVENΗON The control of undesired vegetation is extremely important in achieving high crop efficiency. This can be achieved by the selective control of the growth of weeds in such useful crops as rice among others. The present mechanization of wet-land rice and earlier transplantation have provided more favorable conditions for the growth of weeds than in the past. Consequently, it is necessary to prevent the long-term grown of weeds, and, at the same time, avoid chemical damage to the rice. The need for finding products that achieve these results continues to be commercially important.

Combinations of herbicides are typically used to broaden the spectrum of plant control or enhance the level of control of any given species through additive effect.

Certain rare combinations suφrisingly give a greater-than-additive or synergistic effect on weeds or a less-than-additive or safening effect on the crop. Several such valuable combinations have now been discovered.

SUMMARY OF THE INVENTION This invention relates to mixtures of herbicides that not only provide surprisingly excellent weed control but also have a safening effect on rice. The herbicidal mixtures comprise herbicidally effective amounts of the compound of Formula I in admixture with herbicidally effective amounts of the compound of Formula II and optionally also the compound of Formula HI. This invention also relates to herbicidal compositions comprising effective amounts of the aforesaid mixtures and at least one of the following: surfactant, solid or liquid diluent. This invention also relates to a method of controlling undesired vegetation comprising applying to the locus of the undesired vegetation herbicidally effective amounts of the aforesaid mixtures. The Formulae I, II and IH compounds comprised by the mixtures of this invention are described below:

N-[[(4,6-dimethoxy-2-pyrimidinyl)am--no]carbonyl]-l-memyl-4-(2-memyl-2H-tetrazol^ yl)-lH-pyrazole-5-sulfonamide (azimsulfuron, I);

π

S-(l-methyl-l-phenylethyl) 1-piperidinecarbothioate (dimepiperate, II); and

me yl 2-[[[[[(4,6-dimethoxy-2-pyriπ dinyl)ammo]carrκ>nyl]ammo]su^ methyl]benzoate (bensulfuron methyl, ID) and its agriculturally useful salts.

The compounds of Formulae I and IU can be present in the form of salts. In view of the close relationship between these compounds in their free forms and their agriculturally useful salts, including their equilibration under physiological and environmental conditions, hereinbefore and hereinafter any reference to Formulae I and DI is to be understood as including both the free compounds and their agriculturally useful salts, where appropriate and expedient.

The mixtures of the invention preferred for enhanced herbicidal activity include: a) the compound of Formula I and the compound of Formula π, and b) the compound of Formula I, the compound of Formula II and the compound of Formula HI. The preferred crop for application of the mixtures of the invention is rice, particularly in a paddy field application.

DETAILS OF THE INVENTION The Formula I compound can be prepared as described in U.S. 4,746,353. The synthesis involves the coupling of the pyrazole sulfonamide of Formula 1 with the heterocyclic carbamate of Formula 2.

Dimepiperate (Formula II) is sold by Mitsubishi Petrochemical Co. as the active ingredient in Yu amate® herbicide. Although dimepiperate is most conveniently obtained as a commercial product, it can be prepared by methods described in U.S. 4,343,737.

Bensulfuron methyl (Formula HI) is sold by DuPont as the active ingredient in Londax® herbicide. Although bensulfuron methyl is most conveniently obtained as a commercial product, it and its agriculturally useful salts can be prepared by methods described in U.S. 4,420,325.

The aforementioned compound of Formula I is characterized in that it does not have sufficient herbicidal effect against such broadleaf annual weeds as Carex sp. and Rotala indica, although it does have superior residual effectiveness (duration of activity) in extremely small doses against annual and perennial Cyperaceae weeds (for example, Eleocharis k roguwai and Cyperus serotinus) and against such perennial broadleaf weeds as Sagittaria trifolia and Sagittaria pygmaea. (See U.S. 4,746,353.)

By combining the compound of Formula I with the compound of Formula II in accordance with this invention, a strong herbicidal effect can be obtained on a broad spectrum of weeds, including annual Gramineae and Cyperaceae weeds and broadleaf weeds and perennial Schoenoplectus juncoides, Cyperus serotinus, Sagittaria pygmaea, Sagittaria trifolia and Eleocharis kurguwai. Moreover, marked advantageous characteristics such as long residual effectiveness are obtained. In addition, as shown in the experimental examples described below, the mixtures of this invention greatly reduce the danger of injury to rice plants under poor cultivation conditions (for example, paddies in which the transplanting is shallow or which contain sandy soil, or markedly high temperatures occur after transplanting) as compared to the compound of Formula I used alone. This indicates an excellent interaction between the compound of Formula I and the compound of Formula π that could not be anticipated on the basis of the individual compounds. The herbicidal mixtures of this invention comprising the compound of Formula I and the compound of Formula II are new mixtures not recorded in the literature. The unique safening effect whereby the chemical damage of said herbicidal mixtures to rice plants is gready diminished and safety correspondingly greatly increased was previously completely unknown. The compound of Foπnula I-Q displays herbicidal activity superior to that of previous herbicides against a broad range of weeds ranging from annual weeds to perennial weeds. Moreover, it is characterized in that its effects following a single application are sustained over a long period. It exhibits superior herbicidal activity against such perennial weeds as Eleocharis kuroguwai, Cyperus serotinus and Sagittaria trifolia.

The compound of Formula HI can be appropriately included in mixtures of the compounds of Formulae I and II as a third active component. By this means, outstanding results can be obtained. Effective weed control can achieved by mixtures of the compound of Formula m with the compounds of Formulae I and II, in which the compound of Formula I is present in far smaller amounts than needed for comparable weed control by mixtures of the compounds of Formulae I and II without the compound of Formula ffl. The mixtures of compounds of Formulae I, II and ffl increase efficacy against weeds such that sufficient effectiveness is obtained from a single treatment, the effect is sustained for a long period, and no subsequent development of weeds is seen. Moreover, the safety of said herbicidal mixtures to rice is again suφrisingly increased.

Formulation/Utility

The mixtures of this invention can be applied in their original state, but typically they are mixed with a carrier, and as required, with other auxiliary agents useful for preparing compositions suited to the physical properties of the active ingredients, environmental factors such as soil type, moisture and temperature, mode of application, and the forms in which herbicides are used. Useful forms include, for example, powders, coarse powders, dusts, granules such as pellets, tablets, and films, all of which can be water-dispersible (e.g., "wettable powders") or water-soluble, aqueous and nonaqueous solutions (including emulsifiable concentrates), water-soluble preparations, oil suspensions, emulsions (including microemulsions and or suspoemulsions) and the like which optionally can be thickened into gels. Active ingredients can be (micro)encapsulated and further formed into a suspension or solid formulation; alternatively the entire formulation of active ingredients can be encapsulated (or "overcoated"). Encapsulation- can control or delay release of the active ingredient. Sprayable formulations can be extended in suitable media and used at spray volumes from about one to several hundred liters per hectare. High-strength compositions are primarily used as intermediates for further formulation.

The mixtures of the Formula I and Formula II (and optionally Formula III) compounds can be formulated in a number of ways:

(a) the Formula I and Formula II (and optionally Formula III) compounds can be formulated separately and applied separately or applied simultaneously in an appropriate weight ratio, e.g., as a tank mix; or

(b) the Formula I and Formula II (and optionally Formula III) compounds can be formulated together in the proper weight ratio.

Suitable solid carriers that can be used in preparing the herbicidal compositions of this invention include clays, of which the kaolinite group, the montmorillonite group or the attapulgite group are representative, inorganic substances such as talc, mica, medicinal agalmatolite, silica, vermiculite, gypsum, calcium carbonate, sodium carbonate and bicarbonate, sodium sulfate, dolomite, diatomaceous earth, magnesium lime, phosphorus lime, zeolite, silicic anhydride and synthetic calcium silicate, organic plant substances such as soybean meal, tobacco powder, walnut powder, wheat flour, sawdust, starch, sugar and crystalline cellulose, synthetic or natural polymers such as coumarone resin, petroleum resin, alkyd resin, polyvinyl chloride, polyalkylene glycol, ketone resins, copal gum and dammar gum, waxes such as carnauba wax and beeswax, urea, and appropriate mixtures thereof. Typical solid diluents are described in Watkins, et al., Handbook of Insecticide Dust Diluents and Carriers, 2nd Ed., Dorland Books, Caldwell, New Jersey.

Suitable liquid carriers include paraffinic and naphthenic hydrocarbons such as kerosene, mineral oil, spindle oil, oils of olive, castor, linseed, tung, sesame, com, peanut, cotton-seed, soybean, rape-seed and coconut, fatty acid esters, aromatic hydrocarbons such as toluene, xylene, ethylbenzene, cumene and methylnaphthalene, chlorinated hydrocarbons such as monochlorobenzene and o-chlorotoluene, ethers such as dioxane and tetrahydrofuran, ketones such as acetone, methyl ethyl ketone, 2- heptanone, dϋsobutyl ketone, cyclohexanone, acetophenone, isophorone and 4-hydroxy- 4-methyl-2-pentanone, esters such as ethyl acetate, amyl acetate, ethylene glycol acetate, diethylene glycol acetate, dibutyl maleate and diethyl succinate, alcohols such as methanol, w-hexanol, decanol, ethylene glycol, diethylene glycol, polypropylene glycol, cyclohexanol, tetrahydrofurfuryl alcohol and benzyl alcohol, ether alcohols such as ethylene glycol ethyl ether, ethylene glycol phenyl ether, diethylene glycol ethyl ether and diethylene glycol butyl ether, polar solvents such as N-N-dimethylformamide, N-methylpyrrolidinone, propylene carbonate, dimethyl sulfoxide and water and appropriate mixtures thereof. Typical liquid diluents are described in Marsden, Solvents Guide, 2nd Ed., Interscience, New York, 1950. Surfactants, which are used for the piupose of emulsification, dispersion, moisturization, expansion, bonding, regulation of disintegration, stabilization of effective components, improvement of fluidity and prevention of rusting, may include nonionic, anionic, cationic and amphoteric substances. However, nonionic and/or anionic substances are ordinarily used. Suitable nonionic surfactants that can be used include, for example, substances obtained by polymerization and addition of ethylene oxide to higher alcohols such as lauryl alcohol, stearyl alcohol and oleyl alcohol, substances obtained by polymerization and addition of ethylene oxide to alkyl phenols such as isooctyl phenol and nonyl phenol, substances obtained by polymerization and addition of ethylene oxide to alkyl naphthols such as butyl naphthol and octyl naphthol, substances obtained by polymerization and addition of ethylene oxide to higher fatty acids such as stearic acid and oleic acid, substances obtained by polymerization and addition of ethylene oxide to mono or dialkyl phosphates such as stearyl phosphoric acid and dilauryl phosphoric acid, substances obtained by polymerization and addition of ethylene oxide to amines such as dodecylamine and stearic acid amide, high fatty acid esters of polyvalent alcohols such as sorbitan and substances obtained by polymerization and addition of ethylene oxide to them and substances obtained by polymerization and addition of ethylene oxide and propylene oxide. Suitable anionic surfactants include, for example, alkyl sulfuric acid esters such as sodium lauryl sulfate and oleyl alcohol sulfuric acid ester amine, alkyl sulfonic acid salts such as sodium sulfosuccinic acid dioctyl ester and sodium 2-ethylhexenesulfonate and aryl sulfonic acid salts such as sodium isopropylnaphthalenesulfonic acid, sodium methylenebisnaphthalenesulfonic acid, sodium lignin sulfonate and sodium dodecylbenzenesulfonate, polycarboxylates, and polyoxyethylene polyoxypropylene block copolymers. McCutcheon' s Detergents and Emulsifiers Annual, Allured Publ. Coφ., Ridgewood, New Jersey, as well as Sisely and Wood, Encyclopedia of Surface Active Agents, Chemical Publ. Co., Inc., New York, 1964, list surfactants and recommended uses.

In addition, polymeric compounds and other auxiliary agents such as casein, gelatin, albumin, glues, sodium alginate, carboxymethyl cellulose, methyl cellulose, hydroxyethyl cellulose and polyvinyl alcohol can be used in combination with the herbicidal composition of this invention for the objective of improving the properties of the preparation and increasing its biological effectiveness. The aforementioned carriers and auxiliary agents can be used individually or in combination taking into consideration the type of preparation and the site in which it is to be applied and in accordance with the objectives of its use. All formulations can contain minor amounts of additives to reduce foam, caking, corrosion, microbiological growth and the like, or thickeners to increase viscosity.

Powder preparations, for example, ordinarily contain 1 to 25 parts by weight of the effective compound, with the remaining portion being the solid carrier. Hydrate preparations, for example, ordinarily contain 25 to 90 parts by weight of the effective compound, with the remaining portion being the solid carrier. With dispersed moistening agents, as required, protective colloidal agents, thixotropic agents and defoaming agents can be added.

Granular preparations, for example, ordinarily contain 1 to 35 parts by weight of the effective compound, with the remaining portion being solid carrier. The effective compound may be mixed homogeneously with the solid carrier or it may be affixed or adsorbed homogeneously to the surface of the solid carrier. The diameter of the granules should be approximately 0.2 to 1.5 mm.

Emulsion preparations ordinarily contain 5 to 30 parts by weight of the effective compound and approximately 5 to 20 parts by weight of emulsifying agent, with the remaining portion being a liquid carrier. As required, a rust inhibitor can be added. Solutions, including emulsifiable concentrates, can be prepared by simply mixing the ingredients. Chemically stabilized aqueous sulfonylurea or agriculturally suitable sulfonylurea salt dispersions are taught in U.S. 4,936,900. Solution formulations of sulfonylureas with improved chemical stability are taught in U.S. 4,599,412. Dusts and powders can be prepared by blending and, usually, grinding as in a hammer mill or fluid- energy mill. Suspensions are usually prepared by wet-milling; see, for example, U.S. 3,060,084. Granules and pellets can be prepared by spraying the active material upon preformed granular carriers or by agglomeration techniques. See Browning, "Agglomeration", Chemical Engineering, December 4, 1967, pp 147-48, Perry's Chemical Engineer's Handbook, 4th Ed., McGraw-Hill, New York, 1963, pages 8-57 and following, and WO 91/13546. Pellets can be prepared as described in U.S. 4,172,714. Water-dispersible and water-soluble granules can be prepared as taught in U.S. 4,144,050, U.S. 3,920,442 and DE 3,246,493. Tablets can be prepared as taught in U.S. 5,180,587, U.S. 5,232,701 and U.S. 5,208,030. Films can be prepared as taught in GB 2,095,558 and U.S. 3,299,566. For further information regarding the art of formulation, see U.S. 3,235,361,

Col. 6, line 16 through Col. 7, line 19 and Examples 10-41; U.S. 3,309,192, Col. 5, line 43 through Col. 7, line 62 and Examples 8, 12, 15, 39, 41, 52, 53, 58, 132, 138-140, 162-164, 166, 167 and 169-182; U.S. 2,891,855, Col. 3, line 66 through Col. 5, line 17 and Examples 1-4; Klingman, Weed Control as a Science, John Wiley and Sons, Inc., New York, 1961, pp 81-96; and Hance et al., Weed Control Handbook, 8th Ed., Blackwell Scientific Publications, Oxford, 1989. Examples A-C illustrate the preparation of the herbicidal compositions of this invention. Unless otherwise specified, the term "parts" refers to "parts by weight."

Example A Wettable Powder

Compound of Formula I 0.12 parts Compound of Formula II 30 parts

Sodium lignin sulfonate 5 parts

Sodium dioctyl sulfosuccinate 2 parts

Kaolin 62.88 parts.

The above components were mixed well, pulverized with a hammer mill to particle diameters of less than 5 μ , and remixed to provide a wettable powder.

Example B Pellets

Compound of Formula I 0.04 parts

Compound of Foπnula II 10 parts Neodol® (linear primary alcohol ethoxylate) 0.2 parts

Bentonite 30 parts

Talc 59.76 parts.

The above components were mixed well, pulverized with a hammer mill, kneaded with about 20% thereof of water, extruded through an extrusion-type pelletizer having a diameter of about 1 mm, and cut into about 3-mm long pellets.

Example C Pellets

Compound of Formula I 0.02 parts

Compound of Foπnula II 10 parts Compound of Formula ID 0.1 parts

Neodol® (linear primary alcohol ethoxylate) 0.2 parts

Bentonite 30 parts

Talc 59.68 parts.

The above components were processed as in Example B to provide pellets. The mixtures of this invention can be used alone or in further combination with other commercial herbicides, insecticides or fungicides. A mixture of one or more of the following herbicides with a mixture of this invention may be particularly useful for weed control. Examples of other herbicides with which the mixtures of this invention can be formulated are: anilofos, butachlor, 2-[[2-(3-chlorophenyl)-2-oxiranyl]methyl]-2-ethyl- lH-indene-l,3(2H)-dione (MK-243), cinosulfuron, 3-[l-(3,5-dichlorophenyl)- l-methylethyl]-2,3-dihydro-6-methyl-5-phenyl-4H-l,3-oxazin-4-one, NN-diethyl-

3-[(2,4,6-trimethylphenyl)sulfonyl]-lH-l,2,4-triazole-l-carboxamide (CΗ 900), etobenzanid, mefenacet, methyl 2-[(4,6-dimemoxy-2-pyrirnidinyl)oxy]-6-[l-(methoxy- imino)ethyl]benzoate (KIH 6127), metsulfuron methyl, molinate, pretilachlor, propanil, pyrazosulfuron methyl, pyributicarb and thiobencarb.

In certain instances, combinations with other herbicides having a similiar spectrum of control but a different mode of action will be particularly advantageous for resistance management. The herbicidal compositions of this invention can be used as herbicidal agents for paddy fields. Said compositions are applied to the soil of the paddy field or to the surface of the water of the paddy field when it is flooded before transplantation of the rice seedlings. Said compositions may also be applied to the surface of the water when the paddy is in a flooded state after transplantation of the rice seedlings. There are no particular limitations on the time of application. The herbicidal compositions of this invention can be applied before or after geπnination of the weeds. In general, they should be applied during the period of 0 to 30 days, and preferably, in the period of 3 to 15 days after transplantation of the rice seedlings.

The rice safening action of mixtures of this invention is found over a broad range of ratios of the compound of Foπnula I to the compound of Foπnula π. In general, the compound of Foπnula D, which is particularly effective in controlling Echinochloa sp., is used in a range of amounts of 500 to 12,500 parts by weight, preferably 1,000 to 10,000 parts by weight, and more preferably 1500 to 5000 parts by weight per 100 parts by weight of the compound of Formula I. The compound of Foπnula D is effective in controlling Echinochloa sp. when it is used in amounts greater than 2500 parts by weight per 100 parts by weight of the compound of Formula I.

There are no particular limitations on the quantity of the herbicidal compositions of this invention that are applied. Optimal apphcation rates vary over a wide range depending on the time of use, the mode and ratio of combination of the effective compounds, the properties and state of the paddy field soil, natural conditions, the geographic region and the rice variety. In general, the total quantity of the compound of Formula I and the compound of Formula D applied is approximately 500 to 5000 g ha, preferably approximately 1000 to 4000 g ha, and more preferably approximately 1500 to 3100 g/ha.

The compound of Formula ffl is usefiil as an additional component in combinations ofthe compounds of Formulae I and II over a broad range of ratios. When the compound of Formula ffl is included in the mixtures, the amount of said compound is generally in a range of 100 to 10,000 parts by weight, preferably 300 to 1,500 parts by weight and more preferably 500 to 1,000 parts by weight per 100 parts by weight of the compound of Formula I. When the compound of Formula ffl is included in mixtures of the compounds of Formulae I and π, the amount of the compound of Formula ffl applied is generally approximately 10 to 200 g/ha, preferably approximately 20 to about 100 g ha, and more preferably approximately 24 to 75 g/ha.

One skilled in the art can readily determine herbicidally effective application rates and ratios of the compounds of Formulae I, II and III as well as timing necessary for the desired level of weed control and crop safety. The following test examples demonstrate the control efficacy of the mixtures of this invention against specific weeds. The weed control afforded by the compounds is not limited, however, to these species.

Test Example 1 Plastic pots having 15-cm inside diameter were filled with alluvial paddy field soil, watered and fertilized with 1 g of granular fertilizer containing 15% each of N, P and K. The soil surface was raked, after which the pots were flooded to a water depth of approximately 1 cm. Rice seedlings (variety: Nippon Bare; approximately 2.2-leaf stage) that had been reared separately in a greenhouse were planted four single stem stocks per pot at the depth of 0 cm. Such shallow transplanting under these test conditions makes the rice seedlings particularly vulnerable to herbicide injury. At 5 days after transplanting, the water depth was adjusted to 3 cm, after which the specified amounts of the test compounds were added dropwise to the surface of the water using a pipette. On the 14th day after the chemical treatment, the effects of the compound(s) on the growth and heights of the rice plants were measured. The rating criteria for evaluation of the effects on the growth of the rice plants are indicated below. The results are shown in Table 1. Rating Criteria for Evaluation of Effects on Rice Plants Rating Observation

0: Growth equal to that of untreated group.

1 : Slight inhibition of plant height and leaf color was observed, but recovery occuπed quickly.

2: Inhibition of plant height and leaf color was observed, but recovery occurred quickly.

2.5 : Slight inhibition of plant height, branching and leaf color was observed, and recovery was somewhat slow. 3 : Qear inhibition of plant height and branching was observed, and recovery was somewhat slow.

4: Qear inhibition of plant height, branching and leaf color was observed, and recovery was slow.

5: Clear inhibition of plant height, branching and leaf color was observed, and growth was greatly retarded.

6: Plant height and branching were inhibited to less than 50% of the untreated group, and growth was greatly retarded.

7: Plant height and branching were inhibited, and there was markedly little growth after treatment. 8: There was almost no growth after treatment, and withering or decayed areas were observed on the leaf blades.

10: Completely dead.

Table 1 Effect on Transplanted Rice Plants

Quantity of Compounds Applied (g/ha) Evaluation Relative Plant

Formula I Formula II Formula ffl Rating Height*

Without Formula II

12 — — 7.5 64

24 — — 8.5 64

With Formula TI

12 3000 — 4 87

24 3000 — 6 76

Without Formula II

12 — 60 8 66

24 — 120 8.5 64

With Formula II

12 3000 60 5.5 81

24 3000 120 6 74

* Relative plant heights are reported as percent of height of untreated group.

As can be seen, the compound of Formula D greatly reduces the injurious effect on rice of the compound of Foπnula I alone and the compounds of Foπnula I and ID together. The extent of injury can be further reduced to negligible levels by following commercial practice of transplanting the rice seedlings deeper than 0 cm.

Test Example 2 Plastic pots having 10-cm inside diameter were filled with alluvial paddy field soil, watered and fertilized with 1 g of granular fertilizer containing 15% each of N, P and K. The soil surface was raked, after which the pots were flooded to a water depth of approximately 3 cm. Approximately 20 seeds each of paddy weeds Echinochloa caudata Roshev and Schoenoplectus juncoides were planted per pot. When the weeds reached the 1.5-leaf stage of growth, the specified amounts of the test compounds dissolved in acetone and further diluted with water were added dropwise to the water using a pipette. On the 30th to 40th days after the chemical treatment, the effects of the compound(s) on the weeds were observed. The rating criteria for herbicidal effects were the same as the criteria for evaluation of effects on the rice plants as described for Test Example 1. The results are shown in Table 2. Table 2 Herbicidal Effect on Weeds

Quantity of Compounds Applied (g/ha) Herbicidal Effect

Formula I Formula D E. caudata S. juncoides

Alone

8 — 6 9.5

16 — 8.5 9.5

32 — 9.8 9.5

— 3000 10 0

Mixtures with Formula II

8 3000 10 9.5

16 3000 10 9.5

32 3000 10 9.5

As can be seen, even though the compound of Formula II greatly reduces the injurious effect of the compound of Foπnula I on rice, it does not reduce the herbicidal effect on 5. juncoides. Furthermore, this combination gives complete control of E. caudata.

Claims

CLAIMS What is claimed is:

1. A herbicidally effective mixture comprising azimsulfuron (Formula I) and its agriculturally suitable salts with dimepiperate (Formula II).

2. The mixture of Claim 1 which also contains a herbicidally effective amount of bensulfuron methyl (Formula ffl).

3. An agriculturally suitable composition for controlling the growth of undesired vegetation comprising an effective amount ofthe mixture of Qaim 1 and at least one of the following: surfactant, solid or liquid diluent.

4. An agriculturally suitable composition for controlling the growth of undesired vegetation comprising an effective amount of the mixture of Qaim 2 and at least one of the following: surfactant, solid or liquid diluent.

5. A method for controlling the growth of undesired vegetation by applying to the locus ofthe undesired vegetation a herbicidally effective amount ofthe mixture of Qaim 1.

6. A method for controlling the growth of undesired vegetation by applying to the locus of the undesired vegetation a herbicidally effective amount ofthe mixture of Qaim 2.

7. The method of Qaim 5 wherein the locus of the undesired vegetation is a rice paddy field.

8. The method of Qaim 6 wherein the locus of the undesired vegetation is a rice paddy field.