EP0762833A2

EP0762833A2 - Herbicides for specialty crops

Info

Publication number: EP0762833A2
Application number: EP95913687A
Authority: EP
Inventors: Kofi Sam Amuti
Original assignee: Degussa GmbH; EI Du Pont de Nemours and Co
Current assignee: Evonik Operations GmbH; EIDP Inc
Priority date: 1994-05-27
Filing date: 1995-03-20
Publication date: 1997-03-19
Also published as: BR9507902A; WO1995032621A3; WO1995032621A2; AU1998195A

Abstract

The invention is directed to the use of herbicides of formula (I), wherein R1 is F or Cl; R2 is H, CH¿3?, or CH2CH3; and R?3 is C¿1-C4 alkyl or C1-C4 haloalkyl; or the corresponding N-oxide or their agriculturally suitable salts. Herbicides that comprise compounds of formula (I) provide broad spectrum weed control in plantation crops such as citrus, sugarcane, coffee, banana, oil palm, loblolly pine, rubber, cocoa, grapes, plantain, pineapple, fruit trees, nut trees, and the like.

Description

TITLE HERBICIDES FOR SPECIALTY CROPS This invention comprises certain triazolinones and their agriculturally suitable salts for weed control in plantation crops. Some compounds employed in the instant invention are disclosed in

U.S. 4,881,967. There are, however, no teachings of their use in plantation crops such as citrus, sugarcane, coffee, banana, oil palm, loblolly pine, rubber, cocoa, grapes, plantain, pineapple, and fruit trees such as apples, and nut trees. These crops represent important markets and are cultivated particularly in regions of the Pacific rim and South America. Citrus and loblolly pine also are grown elsewhere.

The yields of selected plantation crops such as citrus, sugarcane, coffee, banana, oil palm, loblolly pine, rubber, cocoa, grapes, and fruit trees tend to be lessened by undesired plants such as crabgrass, guineagrass, itchgrass and the like. In addition, the yields of these crops tend to be reduced by crop plants such as corn, cotton, wheat, rice, and the like. A need therefore exists for controlling undesired plants to improve the yields of plantation crops such as those mentioned above.

SUMMARY OF THE INVENTION This invention comprises a method for controlling weeds in plantation crops comprising applying to the locus to be protected an effective amount of a compound of Formula I:

wherein R¹ is F or Cl;

R² is H, CH₃, or CH₂CH₃; and R³ is Cι-C₄ alkyl or C_rC₄ haloalkyl; or the corresponding N-oxide or agriculturally suitable salt thereof.

For reasons such as ease of synthesis and/or greater herbicidal efficacy, preferred methods-of-use of the invention employ the following compounds: Preferred 1 : The method-of-use described above employing compounds of

Formula I wherein R³ is difluoromethyl. Preferred 2: The method of Preferred 1 wherein the compound is l-(7-chloro-5- fluoro-2,3-dihydro-2-methyl-4-benzofuranyl)-4-difluoromethyl-4,5-dihydro- 3-methyl-l,2,4-triazol-5(lH)-one.

Preferred 3: The method-of-use described above employing compounds of

Formula I wherein the crop is selected from the group consisting of coffee, cocoa, oil palm, sugarcane, citrus, grapes, fruit trees, nut trees, banana, plantain, rubber, pineapple and loblolly pine. Preferred 4: The method of Preferred 3 wherein the plantation crops are selected from the group consisting of sugarcane, citrus, grapes, and fruit trees. Preferred 5: The method of Preferred 2 wherein the plantation crops are selected from the group consisting of coffee, cocoa, oil palm, sugarcane, citrus, grapes, fruit trees, nut trees, banana, plantain, rubber, pineapple and loblolly pine.

Preferred 6: The method of Preferred 5 wherein the plantation crops are selected from the group consisting of sugarcane, citrus, grapes, and fruit trees. Preferred 7: The method of Preferred 4 wherein the crop is citrus. Preferred 8: The method of Preferred 4 wherein the crop is sugarcane. Preferred 9: The method of Preferred 4 wherein the crop is grapes.

Preferred 10: The method of Preferred 2 wherein the crop is fruit trees.

DETAILS OF THE INVENTION Compounds of Formula I can exist as one or more stereoisomers. The various stereoisomers include enantiomers, diastereomers and geometric isomers. One skilled in the art will appreciate that one stereoisomer may be more active than the others and how to separate said stereoisomers. Accordingly, the present invention comprises mixtures, individual stereoisomers, and optically active mixtures of compounds of Formula I as well as agriculturally suitable salts thereof.

In the above recitations, the term "alkyl" used either alone or in compound words such as "haloalkyl" includes straight or branched alkyl such as methyl, ethyl, n-propyl, isopropyl and the different butyl isomers. The prefix "halo" in "haloalkyl", denotes fluorine, chlorine, bromine or iodine. Further, in "haloalkyl", said alkyl can be partially or fully substituted with independently selected halogen atoms. Examples pf haloalkyl include CH₂CH₂F, CF₂CF₃ and CH₂CHFC1. The total number of carbon atoms in a substituent group is indicated by the "C_j-C_j" prefix where i and j are numbers from 1 to 4. For example, C4 alkyl designates the various isomers of an alkyl group containing a total of 4 carbon atoms, examples including CH₂CH₂CH₂CH₃, CH₂CH(CH₃)₂, and C(CH₃)₃. The definitions of R¹ through R³ in the compounds of Formulae 1-8 below are as defined above in the Summary of the Invention.

The preparation of the triazolinone ring is described in U.S. 4,818,275 and is illustrated below in Schemes 1 and 2. Pyruvic acid of Formula I is condensed with the hydrazine of Formula 2 under acidic conditions to form the pyruvic acid hydrazone of Formula 3. Treatment of the hydrazone with diphenylphosphoryl azide and a base such as triethylamine affords the triazolinone of Formula 4.

Scheme 1

3

The triazolinone can be functionalized with R³ to form compounds of Formula I as described in GB 2,090,250 and illustrated in Scheme 2. The triazolinone of Formula 4 is reacted with a base and a haloethylene or an electrophile of Formula R³Z wherein Z is a halide. The reaction is generally performed at a temperature of about 0°-150°C.

Scheme 2

I

An inert solvent is preferably used in the reaction. For example, benzene, toluene, chlorobenzene, xylene, diethyl ether, tetrahydrofuran, dioxane, methanol, ethanol, propanol, ethylene glycol, acetone, methyl ethyl ketone, cyclohexanone, ethyl acetate, dimethylformamide, dimethylacetamide, water, or dimethylsulfoxide can be used. These solvents can be used alone or in combination with one another.

The bases which can be used for the above reaction include, for example, sodium carbonate, potassium carbonate, sodium hydrogen carbonate, potassium hydrogen carbonate, sodium hydroxide, potassium carbonate, sodium methoxide, pyridine, trimethylamine, triethylamine, diethylaniline, or l,8-diazabicyclo[5.4.0]undec-7-ene. Preferred bases .ire sodium hydroxide, potassium hydroxide, and potassium carbonate.

A two-phase reaction can also be used to conduct the reaction, between an aqueous solution layer containing a base such as sodium hydroxide, and an organic solvent layer in the presence of a phase transfer catalyst such as triethylbenzylammonium chloride or tetrabutylammonium bromide.

After the reaction is complete, the desired triazolinone can be obtained through extraction into a water-immiscible solvent and purification by chromatography or recrystallization. The hydrazine of Formula 2 can be prepared from the corresponding aniline using well-known methods for preparing phenylhydrazines (e.g., see J. Timberlake; J. Stowell; The Chemistry of the Hydrazo, Azo, andAzoxy Groups (S. Patai, Ed.) John Wiley and Sons, Ltd., London (1975), p 69; and Demers, J. P.; Klaubert, D. J.; Tetrahedron Lett. (1987), 4933). The aniline can be prepared by reduction of the corresponding nitro-substituted dihydrobenzofuran, for example by hydrogenation over palladium on carbon. The nitro- substituted dihydrobenzofuran can be prepared by the methods disclosed in U.S. 4,881,967, U.S 4,213,773, and U.S. 4,315,767. Several methods are possible. One method involves cyclization of a phenol as illustrated in Scheme 3. The CH₂R⁴ group in Formula 6 corresponds to R² as methyl or ethyl.

Scheme 3

The cyclization can be effected by heating, acid-catalysis, or free radical methods. Preparation of the dihydrobenzofuran can also be accomplished by dehydration of a diol as illustrated in Scheme 4 and taught in U.S. 4,881,967.

Scheme 4

7 8

Alternatively, the dihydrobenzofuran ring can be prepared using the methods illustrated in Schemes 3 and 4 with the triazolinone ring in place of the nitro group.

EXAMPLE 1 Preparation of 1 -(^"7-chloro-5-fluoro-2.3-dihydro-2-methyl-4-benzofuranylV4- difluoromethyl-4.5-dihydro-3-methyl-1.2.4-triazol-5flH one To a solution of 410 mg (1.45 mmol) of l-(7-chloro-5-fluoro-2,3-dihydro-2- methyl-4-benzofiιranyl)-4,5-dihydro-3-methyl-l,2,4-triazol-5(lH)-one in 10 mL of dioxane was added 2 g of 50% aqueous sodium hydroxide and 500 mg (1.55 mmol) of tetrabutylammonium bromide at room temperature. A balloon and condenser filled with dry ice were fitted to the flask. Freon-22 (chlorodifluoromethane) was added by bubbling for 20 min until the balloon had swelled. The mixture was then stirred at room temperature for 3 h. Excess water was added and the aqueous layer was extracted with ethyl acetate. The separated organic layer was washed with water, brine, and dried over anhydrous MgSO The crude product was concentrated under reduced pressure and purified by flash chromatography over silica gel, eluting with a 1 :4 v:v mixture of ethyl acetate and n-hexane to give 200 mg of the title product of Example 1 as a yellow oil. ^!H NMR (CDC1₃, 400 MHz): δ 7.4-6.9 (m,lH), 7.05 (d,lH), 5.05 (m,lH), 3.4 (m,lH), 2.95 (m,lH), 2.4 (s,3H), 1.55 (d,3H).

EXAMPLE 2 Preparation of 1 -(^'7-chloro-5-fluoro-2.3-dihydro-2-methyl-4-benzofuranyl^')-4.5 dihydro-3.4-dimethyl- 12.4-tήazόl-5( lH)-one To a solution of 158 mg (0.58 mmol) of l-(7-chloro-5-fluoro-2,3-dihydro-2- methyl-4-benzofuranyl)-4,5-dihydro-3-methyl-l,2,4-triazol-5(lH)-one in 5 mL of acetonitrile were added 160 mg (1.16 mmol) of potassium carbonate and 72μL (1.16 mmol) of iodomethane in sequence. The solution was then warmed under reflux for 3 h. It was then filtered, concentrated under reduced pressure, and the residue was purified by flash chromatography over silica gel, eluting with a 98:2 v:v mixture of dichloromethane and methanol to give 76 mg of the title product of Example 2 as yellow solid melting at 105-108°C. ^lU NMR (CDC1₃, 400 MHz): δ 7.0 (d,lH), 5.05 (m,lH), 3.4 (m,lH), 3.3 (s,3H), 2.95 (m,lH), 2.3 (s,3H), 1.5 (d,3H).

By the procedures described herein, the compounds in Table 1 can be prepared.

Table 1

Compounds of Formula I wherein:

E¹ R² E³ E¹ E² E³ E¹ E² E³

F H CF₂H F H CH₃ F H CF₃

F CH₃ CF₂H F CH₃ CH₃ F CH₃ CF₃

F CH₂CH₃ CF₂H F CH₂CH₃ CH₃ F CH₂CH₃ CF₃

Cl H CF₂H Cl H CH₃ Cl H CF₃

Cl CH₃ CF₂H Cl CH₃ CH₃ Cl CH₃ CF₃

Cl CH₂CH₃ CF₂H Cl CH₂CH₃ CH₃ Cl CH₂CH₃ CF₃

F CH₃ CH₂CF₂H F CH₃ CH₂CH₃ F CH₃ CH₂CF₃

F CH₃ (CH₂)₃CF₂H F CH₃ (CH₂)₃CH₃ F CH₃ (CH₂)₃CF₃

Formulation/Utilitv Compounds of this invention will generally be used in formulation with an agriculturally suitable carrier comprising a liquid or solid diluent and/or a surfactant wherein the formulation is consistent with the physical properties of the active ingredient, mode of application and environmental factors such as soil type, moisture and temperature. Useful formulations include liquids such as solutions (including emulsifiable concentrates), suspensions, emulsions (including microemulsions and/or suspoemulsions) and the like which optionally can be thickened into gels. Useful formulations further include solids such as dusts, powders, granules, pellets, tablets, films, and the like which can be water-dispersible ("wettable") or water-soluble. Active ingredient can be (micro)encapsulated and further formed into a suspension or solid formulation; alternatively the entire formulation of active ingredient 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 formulations will typically contain effective amounts of active ingredient, diluent and surfactant within the following approximate ranges which add up to 100 percent by weight.

Weight Percent

Active Ingredient Diluent Surfactant

Water-Dispersible and Water-soluble 5-90 0-74 1-15 Granules, Tablets and Powders.

Suspensions, Emulsions, Solutions 5-50 40-95 0-15 (including Emulsifiable Concentrates)

Dusts 1-25 70-99 0-5

Granules and Pellets 0.01-99 5-99.99 0-15

High Strength Compositions 90-99 0-10 0-2

Typical solid diluents are described in Watkins, et al., Handbook of Insecticide Dust Diluents and Carriers, 2nd Ed., Dorland Books, Caldwell, New Jersey. Typical liquid diluents are described in Marsden, Solvents Guide, 2nd Ed., Interscience, New York, 1950. McCutcheon 's Detergents and Emulsifiers Annual, Allured Publ. Corp., 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. All formulations can contain minor amounts of additives to reduce foam, caking, corrosion, microbiological growth and the like, or thickeners to increase viscosity. Surfactants include, for example, polyethoxylated alcohols, polyethoxylated alkylphenols, polyethoxylated sorbitan fatty acid esters, dialkyl sulfosuccinates, alkyl sulfates, alkylbenzene sulfonates, organosilicones, N,_V-dialkyltaurates, lignin sulfonates, naphthalene sulfonate formaldehyde condensates, polycarboxylates, and polyoxyethylene/polyoxypropylene block copolymers. Solid diluents include, for example, clays such as bentonite, montmorillinite, attapulgite and kaolin, starch, sugar, silica, talc, diatomaceous earth, urea, calcium carbonate, sodium carbonate and bicarbonate, and sodium sulfate. Liquid diluents include, for example, water, N,N-dimethylformamide, dimethyl sulfoxide, N-alkylpyrrolidone, ethylene glycol, polypropylene glycol, paraffins, alkylbenzenes, alkylnaphthalenes, oils of olive, castor, linseed, tung, sesame, corn, peanut, cotton-seed, soybean, rape-seed and coconut, fatty acid esters, ketones such as cyclohexanone, 2-heptanone, isophorone and 4-hydroxy-4- methyl-2-pentanone, and alcohols such as methanol, cyclohexanol, decanol and tetrahydrofurfuryl alcohol.

Solutions, including emulsifiable concentrates, can be prepared by simply mixing the ingredients. 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.

In the following Examples, all percentages are by weight and all formulations are prepared in conventional ways.

Example A High Strength Concentrate 1 -(7-chloro-5-fluoro-2,3-dihydro-2-methyl-4-benzofuranyl)-

4-difluoromethyl-4,5-dihydro-3-methyl- 1 ,2,4-triazol-5( lH)-one 98.5% silica aerogel 0.5% synthetic amorphous fine silica 1.0%. Example B Wettable Powder l-(7-chloro-5-fluoro-2,3-dihydro-2-methyl-4-benzofuranyl)- 4-difluoromethyl-4,5-dihydro-3-methyl- 1 ,2,4-triazol-5( lH)-one 65.0% dodecylphenol polyethylene glycol ether 2.0% sodium ligninsulfonate 4.0% sodium silicoaluminate 6.0% montmorillonite (calcined) 23.0%.

Example C Granule l-(7-chloro-5-fluoro-2,3-dihydro-2-methyl-4-benzofuranyl)- 4-difluoromethyl-4,5-dihydro-3-methyl- 1 ,2,4-triazol-5( lH)-one 10.0% attapulgite granules (low volatile matter, 0.71/0.30 mm; U.S.S. No. 25-50 sieves) 90.0%.

Example D Extruded Pellet l-(7-chloro-5-fluoro-2,3-dihydro-2-methyl-4-benzofuranyl)- 4-difluoromethyl-4,5-dihydro-3-methyl- 1 ,2,4-triazol-5( lH)-one 25.0% anhydrous sodium sulfate 10.0% crude calcium ligninsulfonate 5.0% sodium alkylnaphthalenesulfonate 1.0% calcium/magnesium bentonite 59.0%.

The compounds of Formula I are active herbicides for selective and/or general broadleaf and grass weed control in plantation crops including coffee, cocoa, oil palm, sugarcane, citrus, grapes, fruit trees, nut trees, banana, plantain, rubber, pineapple and loblolly pine. Preferred is the method of using compounds of Formula I in sugarcane, citrus, grapes, and fruit trees.

The compounds of Formula I can be applied as a preemergence or postemergence treatment using techniques such as banding, directed sprays, or broadcast applications. By selecting the appropriate rate which would be apparent to one skilled in the art, the compounds of Formula I can be used in areas where control of vegetation is desired, such as around fuel storage tanks, industrial storage areas, oil well sites, drive-in theaters, around billboards, highway and railroad structures and in fence rows. Alternatively, by selecting the proper rates, adjuvants and application methods, the compounds of Formula I can be used for selective weed control in plantation crops. In general, the compounds of this invention are used at 5 to 5000 g/ha with a preferred rate range of 10 to 2000 g/ha rate. One skilled in the art can select the proper rates for a given situation.

Compositions comprising the active compounds of Formula I are generally used alone or in combination with other commercial herbicides, insecticides or fungicides. The compounds of Formula I are particularly useful in combinations with other herbicides for total vegetation control in plantation crops. Examples of other herbicides with which compounds of Formula I can be formulated are: acetochlor, acifluorfen, acrolein, azimsulfuron, 2-propenal, alachlor, ametryn, amidosulfuron, ammonium sulfamate, amitrole, anilofos, asulam, atrazine, barban, benazolin, benefin, benfuresate, bensulfuron methyl, bensulide, bentazon, benzofluor, benzoylprop, bifenox, bromacil, bromoxynil, bromoxynil heptanoate, bromoxynil octanoate, butachlor, buthidazole, butralin, butylate, cacodylic acid, 2-chloro-N,N-di-2-propenylacetamide, 2-chloroallyl diethyldithiocarbamate, chloramben, chlorbromuron, chloridazon, chlorimuron ethyl, chlormethoxynil, chlornitrofen, chloroxuron, chlorpropham, chlorsulfuron, chlortoluron, cinmethylin, cinosulfuron, clethodim, clomazone, cloproxydim, clopyralid, calcium salt of methylarsonic acid, cyanazine, cycloate, cyclosulfamuron, cycluron, cyperquat, cyprazine, cyprazole, cypromid, dalapon, dazomet, dimethyl 2,3,5,6-tetrachloro-l,4-benzenedicarboxylate, desmedipham, desmetryn, dicamba, dichlobenil, dichlorprop, diclofop, diethatyl, difenzoquat, diflufenican, dimepiperate, dinitramine, dinoseb, diphenamid, dipropetryn, diquat, diuron, 2-methyl-4,6- dinitrophenol, disodium salt of methylarsonic acid, dymron, endothall, 5-ethyl dipropylcarbamothioate, esprocarb, ethalfluralin, ethametsulfuron methyl, ethofumesate, fenac, fenoxaprop, fenuron, salt of fenuron and trichloroacetic acid, flamprop, fluazifop, fluazifop-butyl, fluazifop-P, fluazifop-P-butyl, fluchloralin, flumesulam, flumicloral- pentyl, flumioxazin, flumipropyn, fluometuron, fluorochloridone, fluorodifen, fluoroglycofen, flupoxam, fluridone, fluroxypyr, fluzasulfuron, fomesafen, fosamine, glufosinate, glufosinate-ammonium, glyphosate, glyphosate-isopropylammonium, glyphosate-sesquisodium, glyphosate-trimesium, haloxyfop, hexaflurate, hexazinone, imazamethabenz, imazapyr, imazaquin, imazamethabenz methyl, imazethapyr, imazosulfuron, ioxynil, isopropalin, isoproturon, isouron, isoxaben, karbutilate, lactofen, lenacil, linuron, metobenzuron, metsulfuron methyl, methylarsonic acid, monoammonium salt of methylarsonic acid, (4-chloro-2-methylphenoxy)acetic acid, 5,5'-dimethyl-2- (difluoromemyl)-4-(2-methylpropyl)-6-(trifluoromethyl)-3,5-pyridinedicarbothioate, mecoprop, mefenacet, mefluidide, methalpropalin, methabenzthiazuron, metham, methazole, methoxuron, N-[[(4-methoxy-6-methyl-l,3,5-triazin-2-yl)amino]carbonyl]-2- (3,3 ,3-trifluoropropyl)benzenesulfonamide, methyl [[2-chloro-4-fluoro-5-[(tetrahydro-3- oxo-lH,3H-[l,3,4]tMadiazolo[3,4- ]pyridazin-l-yMdene)amino]phenyl]thioacetate, metolachlor, metribuzin, l,2-dihydropyridazine-3,6-dione, molinate, monolinuron, monuron, monuron salt and trichloroacetic acid, monosodium salt of methylarsonic acid, napropamide, naptalam, neburon, nicosulfuron, nitralin, nitrofen, nitrofluorfen, norea, norflurazon, oryzalin, oxadiazon, oxyfluorfen, paraquat, pebulate, pendimethalin, perfluidone, phenmedipham, picloram, 5-[2-chloro-4-(trifluoromethyl)phenoxy]-2- nitroacetophenone oxime-O-acetic acid methyl ester, pretilachlor, primisulfuron, procyazine, profluralin, prometon, prometryn, pronamide, propachlor, propanil, propazine, propham, prosulfalin, prynachlor, pyrazolate, pyrazon, pyrazosulfuron ethyl, quinchlorac, quizalofop-ethyl, quizalofop-P-ethyl, rimsulfiiron, secbumeton, sethoxydim, siduron, simazine, l-(α,α-dimethylbenzyl)-3-(4-methylphenyl)urea, sulfentrazone, sulfometuron methyl, trichloroacetic acid, tebuthiuron, terbacil, terbuchlor, terbuthylazine, terbutol, terbutryn, thenylchlor, thifensulfuron methyl, thiobencarb, tri- allate, trialkoxydim, triasulfuron, tribenuron methyl, triclopyr, tridiphane, trifluralin, triflusulfuron methyl, trimeturon, (2,4-dichlorophenoxy)acetic acid, 4-(2,4-dichlorophenoxy)butanoic acid, vernolate, and xylachlor. In certain instances, combinations with other herbicides having a similar spectrum of control but a different mode of action will be particularly advantageous for management of resistant weeds.

Preferred are mixtures of l-(7-chloro-5-fluoro-2,3-dihydro-2-methyl-4- benzofuranyl)-4-difluoromethyl-4,5-dihydro-3-methyl- 1 ,2,4-triazol-5( lH)-one (Compound No. 1) with diuron, fluazifop-butyl, fluazifop-P-butyl, glufosinate, glufosinate-ammonium, glyphosate, glyphosate-isopropylammonium, glyphosate-sesquisodium, glyphosate-trimesium, hexazinone, metribuzin, norflurazon, paraquat, quizalofop-ethyl, or quizalofop-P-ethyl.

The following Tests demonstrate the control efficacy of two compounds of Formula I, Compounds No. 1 and 2, against specific weeds. The weed control afforded by the compounds is not limited, however, to these species.

Compound No. 1 Compound No.2 TEST A Seeds of barley (Hordeum vulgare), barnyardgrass (Echinochloa crus-galli), bedstraw (Galium aparine), blackgrass (Alopecurus myosuroides), cheatgrass (Bromus secalinus), chickweed (Stellaria media), cocklebur (Xanthium pensylvanicum), corn (Zea mays), cotton (Gossypium hirsutum), crabgrass (Digitaria sanguinalis), downy brome (Bromus tectorum), giant foxtail (Setariafaberiϊ), lambsquarters (Chenopodium album), morningglory (Ipomoea hederaceά), rape (Brassica napus), rice (Oryza sativa), sorghum (Sorghum bicolor), soybean (Glycine max), sugar beet (Beta vulgaris), velvetleaf (Abutilon theophrastϊ), wheat (Triticum aestivum), wild buckwheat (Polygonum convolvulus), wild oat (Avenafatua) and purple nutsedge (Cyperus rotundas) tubers were planted and treated preemergence with test chemicals formulated in a non-phytotoxic solvent mixture which includes a surfactant. At the same time, these crop and weed species were also treated with postemergence applications of test chemicals formulated in the same manner. Plants ranged in height from two to eighteen cm (one to four leaf stage) for postemergence treatments. Treated plants and controls were maintained in a greenhouse for twelve to sixteen days, after which all species were compared to controls and visually evaluated. Plant response ratings, summarized in Table A, are based on a scale of 0 to 10 where 0 is no effect and 10 is complete control. A dash (-) response means no test result.

Table A COMPOUND Table A COMPOUND

Rate 400 g/ha 1 2 Rate 400 g/ha 1 2

POSTEMERGENCE PREEMERGENCE

Barley 9 5 Barley 7 4

Barnyardgrass 10 9 Barnyardgrass 10 9

Bedstraw 10 8 Bedstraw 10 8

Blackgrass 9 5 Blackgrass 10 9

Cheatgrass 9 6 Cheatgrass 10 5

Chickweed 8 6 Chickweed 10 6

Cocklebur 8 6 Cocklebur 7 3

Corn 10 7 Corn 9 8

Cotton 10 10 Cotton 10 4

Crabgrass 9 7 Crabgrass 10 10

Giant foxtail 9 8 Giant foxtail 10 10

Lambsquarter 10 9 Lambsquarter 10 10

Morningglory 9 10 Morningglory 10 10

Nutsedge 9 2 Nutsedge 7 6

Rape 9 7 Rape 10 9

Rice 9 8 Rice 9 7

Sorghum 10 8 Sorghum 10 10

Soybean 9 9 Soybean 10 9

Sugar beet 10 10 Sugar beet 10 10

Velvetleaf 10 10 Velvetleaf 10 10

Wheat 8 7 Wheat 9 3

Wild buckwheat 10 10 Wild buckwheat 10 10

Wild oat 9 9 Wild oat 10 6

Table A COMPOUND Table A COMPOUND

Rate 100 g/ha 1 2 Rate 100 g/ha 1 2

POSTEMERGENCE PREEMERGENCE

Barley 8 3 Barley 3 0

Barnyardgrass 10 6 Barnyardgrass 10 9

Bedstraw 10 5 Bedstraw 10 8

Blackgrass 7 3 Blackgrass 9 2

Cheatgrass 8 3 Cheatgrass 10 1

Chickweed 8 4 Chickweed 9 2

Cocklebur 7 6 Cocklebur 2 0

Corn 8 3 Corn 9 3

Cotton 10 10 Cotton 2 0

Crabgrass 9 3 Crabgrass 10 9

Giant foxtail 9 8 Giant foxtail 10 10

Lambsquarter 10 9 Lambsquarter 10 10

Morningglory 8 8 Morningglory 10 6

Nutsedge 5 1 Nutsedge 2 0

Rape 8 5 Rape 6 8

Rice 9 6 Rice 8 5

Sorghum 8 6 Sorghum 9 1

Soybean 9 8 Soybean 9 9

Sugar beet 10 9 Sugar beet 10 9

Velvetleaf 10 10 Velvetleaf 10 9

Wheat 9 4 Wheat 4 0

Wild buckwheat 10 9 Wild buckwheat 10 10

Wild oat 9 7 Wild oat 9 1

TESTB

Seeds, rhizomes, or plant parts of alfalfa (Medicago sativa), annual bluegrass (Poa annua), bermudagrass (Cynodon dactyloή), broadleaf signalgrass (Brachiaria platyphylla), common purslane (Portulaca oleracea), common ragweed (Ambrosia artemisiifolia), dallisgrass (Paspalum dilatatum), goosegrass (Eleusine indica), guineagrass (Panicum maximum), itchgrass (Rottboellia cochinchinensis), johnsongrass (Sorghum halepense), large crabgrass (Digitaria sanguinalis), peanut (Arachis hypogaea), pitted morningglory (Ipomoea lacunosa), purple nutsedge (Cyperus rotundus), sandbur (Southern sandbur), smooth crabgrass (Digitaria ischaemum), sugarcane (Saccharum officinarum) and yellow nutsedge (Cyperus esculentus) were planted into greenhouse pots containing greenhouse planting medium. Each pot contained only one plant species.

The test compound was formulated in a non-phytotoxic solvent mixture which includes at least one surfactant and applied preemergence and/or postemergence to the plants. Preemergence applications were made within one day of planting the seeds or plant parts. Postemergence applications were applied when the plants were in the two to four leaf stage (three to twenty cm). Untreated control plants and treated plants were placed in the greenhouse and visually evaluated for injury at 14 to 28 days after herbicide application. Plant response ratings, summarized in Table B, are based on a 0 to 100 scale where 0 is no injury and 100 is complete control. A dash (-) response indicates no test result.

Table B COMPOUND Table B COMPOUND

Rate 500 g/ha 1 Rate 500 g/ha 1

POSTEMERGENCE PREEMERGENCE

Alfalfa var. 50 Alfalfa var. 70

Ann bluegrass 0 Ann bluegrass 90

Bermudagrass 30 Bermudagrass 100

Brdlf signalgrass 20 Brdlf signalgrass 100

Cmn purslane 40 Cmn purslane 100

Cmn Ragweed - Cmn ragweed 100

Dallisgrass 0 Dallisgrass 100

Goosegrass 0 Goosegrass 100

Guineagrass 20 Guineagrass 100

Itchgrass 30 Itchgrass 100

Johnsongrass 20 Johnsongrass 100

Large crabgrass 0 Large crabgrass 100

Peanuts 30 Peanuts 0

Pit morningglory 30 Pit morningglory 60

Purple nutsedge 0 Purple nutsedge 0

Sandbur - Sandbur 100

Smooth crabgrass 0 Smooth crabgrass 100

Sugarcane - Sugarcane -

Yellow nutsedge 0 Yellow nutsedge 0 Table B COMPOUND Table B COMPOUND

Rate 250 g/ha 1 2 Rate 250 g/ha 1 2

POSTEMERGENCE PREEMERGENCE

Alfalfa var. 44^a 0 Alfalfa var. 67^a 20

Ann bluegrass 2^a 0 Ann bluegrass 56^a 20

Bermudagrass 22^a 0 Bermudagrass 100^a 80

Brdlf signalgrass 7^a 0 Brdlf signalgrass 100^a 30

Cmn purslane 67^a 20 Cmn purslane ₉₇a 20

Cmn ragweed 7^a 0 Cmn ragweed 7^a 0

Dallisgrass ₁₇a 0 Dallisgrass 100^a 100

Goosegrass 30^a 0 Goosegrass 100^a 100

Guineagrass 5^a 0 Guineagrass 100^a 70

Itchgrass 22^a 0 Itchgrass 97^a 0

Johnsongrass 5^a 0 Johnsongrass 81^a 20

Large crabgrass 10^a 0 Large crabgrass 100^a 90

Peanuts 5^a 10 Peanuts 29^a 20

Pit morningglory 22^a 60 Pit morningglory 36^a 30

Purple nutsedge 7^a 0 Purple nutsedge 20^a 0

Sandbur 23^a 0 Sandbur 84^a 0

Smooth crabgrass 10^a 0 Smooth crabgrass 100^a 100

Sugarcane 35 - Sugarcane 20 -

Yellow nutsedge 0 0 Yellow nutsedge 0 0

^aThis result is an average of more than one replication of the same test.

Table B COMPOUND Table B COMPOUND

Rate 125 g/ha 1 Rate 125 g/ha 1

POSTEMERGENCE PREEMERGENCE

Alfalfa var. 20 Alfalfa var. 70

Ann bluegrass 0 Ann bluegrass 30

Bermudagrass 0 Bermudagrass 100

Brdlf signalgrass 0 Brdlf signalgrass 100

Cmn purslane 100 Cmn purslane 100

Cmn Ragweed - Cmn Ragweed -

Dallisgrass 70 Dallisgrass 100

Goosegrass 30 Goosegrass 100

Guineagrass 0 Guineagrass 100

Itchgrass 0 Itchgrass 100

Johnsongrass 0 Johnsongrass 100

Large crabgrass 0 Large crabgrass 100

Peanuts 20 Peanuts 0

Pit morningglory 0 Pit morningglory 0

Purple nutsedge 0 Purple nutsedge 0

Sandbur 0 Sandbur 100

Smooth crabgrass 0 Smooth crabgrass 100

Sugarcane - Sugarcane -

Yellow Nutsedge Yellow Nutsedge

TESTC

Seeds of barnyardgrass (Echinochloa crus-galli), bindweed (Concolculus arvensis), black nightshade (Solanum ptycanthum dunaϊ), cassia (Cassia obtusifolia), cocklebur (Xanthium pensylvanicum), common ragweed (Ambrosia artemisiifolia), corn (Zea mays), cotton (Gossypium hirsutam), crabgrass (Digitaria spp.), fall panicum (Panicum dichotomiflorum), giant foxtail (Setariafaberii), green foxtail (Setaria viridis), jimsonweed (Datura stramonium), johnsongrass (Sorghum halepense), lambsquarter (Chenopodium album), morningglory (Ipomoea spp.), pigweed (Amaranthus retroflexus), prickly sida (Sida spinosa), shattercane (Sorghum vulgare), signalgrass (Brachiaria platyphylla), smartweed (Polygonum pensylvanicum), soybean (Glycine max), sunflower (Helianthus annuus), velvetleaf (Abutilon theophrasti), wild proso (Pancium miliaceum), woolly cupgrass (Eriochloa villosa), yellow foxtail (Setaria lutescens) and purple nutsedge (Cyperus rotundus) tubers were planted into a matapeake sandy loam soil. These crops and weeds were grown in the greenhouse until the plants ranged in height from two to eighteen cm (one to four leaf stage), then treated postemergence with the test chemicals formulated in a non-phytotoxic solvent mixture which includes at least one surfactant. Pots receiving preemergence treatments were planted immediatley prior to test chemical application. Pots treated in this fashion were placed in the greenhouse and maintained according to routine greenhouse procedures. Treated plants and untreated controls were maintained in the greenhouse approximately 14-21 days after application of the test compound. Visual evaluations of plant injury responses were then recorded. Plant response ratings, summarized in Table C, are reported on a 0 to 100 scale where 0 is no effect and 100 is complete control.

TABLE COMPOUND TABLE C COMPOUND Rate 280 g/ha 1 Rate 140 g/ha 1 PREEMERGENCE PREEMERGENCE Barnyardgrass 100 Barnyardgrass 100 Bindweed 100 Bindweed 85 Blk Nightshade 100 Blk Nightshade 100

Cassia 75 Cassia 55

Cocklebur 65 Cocklebur 50

Corn 90 Corn 85

Cotton 65 Cotton 50

Crabgrass 100 Crabgrass 100

Fall Panicum 100 Fall Panicum 100

Giant Foxtail 100 Giant Foxtail 100

Green Foxtail 100 Green Foxtail 100

Jimsonweed 100 Jimsonweed 100

Johnson Grass 100 Johnson Grass 100

Lambsquarter 100 Lambsquarter 100

Morningglory 65 Morningglory 60

Nutsedge 90 Nutsedge 70

Pigweed 100 Pigweed 100

Prickly Sida 100 Prickly Sida 100

Ragweed 100 Ragweed 80

Shattercane 100 Shattercane 100

Signalgrass 100 Signalgrass 100

Smartweed 100 Smartweed 100

Soybean 100 Soybean 95

Sunflower 85 Sunflower 65

Velvetleaf 100 Velvetleaf 100

Wild Proso 100 Wild Proso 100

Woolly cupgrass 100 Woolly cupgrass 100

Yellow Foxtail 100 Yellow Foxtail 100 TABLE C COMPOUND TABLE C COMPOUND Rate 70 g/ha 1 Rate 35 g/ha 1 PREEMERGENCE PREEMERGENCE Barnyardgrass 100 Barnyardgrass 95 Bindweed 15 Bindweed 15 Blk Nightshade 100 Blk Nightshade 100

Cassia 25 Cassia 15

Cocklebur 45 Cocklebur 40

Corn 85 Corn 80

Cotton 30 Cotton 25

Crabgrass 100 Crabgrass 80

Fall Panicum 100 Fall Panicum 100

Giant Foxtail 100 Giant Foxtail 65

Green Foxtail 100 Green Foxtail 80

Jimsonweed 100 Jimsonweed 95

Johnson Grass 100 Johnson Grass 80

Lambsquarter 100 Lambsquarter 95

Morningglory 20 Morningglory 15

Nutsedge 45 Nutsedge 20

Pigweed 100 Pigweed 95

Prickly Sida 100 Prickly Sida 85

Ragweed 30 Ragweed 0

Shattercane 70 Shattercane 55

Signalgrass 95 Signalgrass 75

Smartweed 100 Smartweed 100

Soybean 55 Soybean 45

Sunflower 50 Sunflower 15

Velvetleaf 80 Velvetleaf 65

Wild Proso 100 Wild Proso 85

Woolly cupgrass 100 Woolly cupgrass 60

Yellow Foxtail 95 Yellow Foxtail 80 TABLE C COMPOUND

Rate 17 g/ha 1

PREEMERGENCE

Barnyardgrass 25

Bindweed 0

Blk Nightshade 100

Cassia 0

Cocklebur 0

Corn 55

Cotton 0

Crabgrass 20

Fall Panicum 55

Giant Foxtail 50

Green Foxtail 50

Jimsonweed 80

Johnson Grass 65

Lambsquarter 80

Morningglory 0

Nutsedge 0

Pigweed 70

Prickly Sida 30

Ragweed 0

Shattercane 15

Signalgrass 60

Smartweed 85

Soybean 10

Sunflower 0

Velvetleaf 0

Wild Proso 20

Woolly cupgrass 15

Yellow Foxtail 55

TEST D Seeds or stem cuttings of sugarcane, alexandergrass (Brachiarai plantaginea), itchgrass (Rottboellia exaltata), johnsongrass (Sorghum halepense), surinamgrass (Brachiarai decumbens) and guineagrass (Panicum maximum) were planted in pots containing greenhouse planting medium. The pots were sprayed preemergence with the compound formulated in a non-phytotoxic solvent mixture which includes a surfactant. The treatments were visually rated 23 and 51 days-after-treatment (DAT) and compared with appropriate controls. The plant response ratings scale used in Test B were also used here. The results are shown in Table D. A dash indicates the test was not run.

TABLE D

Compound 1

125 64 32 16 g a.i./ha 23 DAT

Sugarcane 0 0 0

Brachiaria plantaginea 100 100 40 0

Itchgrass 100 80 30 0

Johnsongrass 100 80 40 0

Brachiaria decumbens 100 80 0 0

Guineagrass 100 100 80 30 51 DAT

Sugarcane 0 0 0

Brachiaria plantaginea 100 100 70 0

Itchgrass 100 100 0 0

Johnsongrass 100 90 50 0

Brachiaria decumbens 100 90 0 0

Guineagrass 100 100 80 20

TEST E Seeds of soybean, purslane, guineagrass, itchgrass, johnsongrass, wheat, corn, shattercane, velvetleaf, peanut, galiu , nightshade, goosegrass, large crabgrass, pitted morningglory and sandbur were planted in flats filled with planting medium. Planting was staggered so that the preemergence and postemergence treatments were applied at the same time with the compound formulated in a non-phytotoxic solvent mixture which includes a surfactant. The plants treated postemergence ranged from four to ten leaf stage and some had also flowered. The treatments were visually rated and compared with appropriate controls at the end of the test. Plant response ratings are summarized in Table E and are based on the same scale as that of Test B. 23

TABLE 1 E

Compound 1

64 32 16 8 4 g a.i./ha

Preemergence

Soybean 0 0 0 0 0

Purslane 100 70 70 50 0

Guineagrass 100 80 60 30 0

Itchgrass 100 30 0 0 0

Johnsongrass 100 40 40 40 0

Wheat 0 0 0 0 0

Corn 0 0 0 0 0

Shattercane 80 40 40 0 0

Velvetleaf 100 30 30 0 0

Peanut 0 0 0 0 0

Galium 30 30 30 20 0

Nightshade 80 40 20 20 0

Goosegrass 100 60 60 60 0

Large crabgrass 100 40 40 20 0

Pitted morningglory 60 0 0 0 0

Compound 1

64 32 16 8 4 g .i./ha

Postemergence

Soybean 60 40 40 30 20

Guineagrass 0 0 0 0 0

Itchgrass 0 0 0 0 0

Johnsongrass 0 0 0 0 0

Wheat 30 10 10 10 0

Corn 30 20 20 20 20

Shattercane 0 0 0 0 0

Velvetleaf 20 10 0 0 0

Peanut 10 0 0 0 0

Galium 60 60 30 30 20

Nightshade 100 20 10 0 0

Goosegrass 40 30 20 20 0

Large crabgrass 0 0 0 0 0

Pitted morningglory 40 20 0 0 0

Sandbur 0 0 0 0 0 TEST F

Rooted cuttings of citrus were planted in plastic pots. The pots were also seeded with guineagrass, sandbur, goosegrass and green pigweed (Amaranthus viridis), another pot was planted with sugarcane stem pieces and purple nutsedge tubers.

The citrus was sprayed to simulate field type post-directed herbicide application, the sugarcane and purple nutsedge were treated postemergence and the weeds were treated preemergence with the compound in a non-phytotoxic solvent mixture which includes a surfactant. Treated plants were visually rated and compared with appropriate controls. The plant response ratings used in Test B were also used here. The results are shown in Table F.

TABLE F

Compound 1

125 64 g a . i . /ha

Post-directed

Citrus 0 0

Postemerσence

Sugarcane 0 0

Purple nutsedge 0 0

Preemerσence

Guineagrass 70 0

Sandbur 60 0

Goosegrass 100 80

Green pigweed 100 60

Claims

CLAIMS 1. A method for controlling weeds in plantation crops comprising applying to the locus to be protected an effective amount of a compound of Formula I:

wherein

R¹ is F or Cl;

R² is H, CH₃, or CH₂CH₃; and

R³ is C_rC alkyl or C_rC₄ haloalkyl; or the corresponding N-oxide or agriculturally suitable salt thereof.

2. A method according to Claim 1 wherein: R³ is difluoromethyl.

3. A method according to Claim 2 wherein the compound is l-(7-chloro-5- fluoro-2,3-dihydro-2-me yl-4-benzofuranyl)-4-ά fluoromethyl-4,5-dihydro-3-methyl- 1 ,2,4-triazol-5( lH)-one.

4. A method according to Claim 1 wherein the plantation crop is selected from the group consisting of coffee, cocoa, oil palm, sugarcane, citrus, grapes, fruit trees, nut trees, banana, plantain, rubber, pineapple and loblolly pine.

5. A method according to Claim 4 wherein the plantation crop is selected from the group consisting of sugarcane, citrus, grapes, and fruit trees.

6. A method according to Claim 5 wherein the crop is citrus.

7. A method according to Claim 5 wherein the crop is sugarcane.

8. A method according to Claim 5 wherein the crop is grapes.

9. A method according to Claim 3 wherein the plantation crop is selected from the group consisting of coffee, cocoa, oil palm, sugarcane, citrus, grapes, fruit trees, nut trees, banana, plantain, rubber, pineapple and loblolly pine.

10. A method according to Claim 3 wherein the plantation crop is selected from the group consisting of sugarcane, citrus, grapes and fruit trees.