Method for combatting blackgrass in cereal crops and compositions therefor

Description

חוק הפטנטים׳ תשכ״ז-1967PATENT LAW, 5727- 196705.56.23For Office UseApplication for PatentNumber66359 / 302018 cmI (Name and address of applicant, and in case ot body corporate-place of incorporation)Date21 / VI 1 / 1982Anfe / Posf-daied'אגן", יצרני כימיקלים בע״מ ת.ד. 262אשדוד - , 77102AGAN CHEMICAL MANUFACTURERS LTD.P.O.B. 262ASHDODבעל אמצאה מכה.............."1י1............................... ;............................... ששמה הואof an invention the title of which is                                                                                 Owner, by virtue of(בעברית) שיטה להדביר זאב השועל בדגנים ותכשירים למטרה זו המכילים טריאזין מותמר Hebrew)) ודיניטרואניליו מותמר.(באנגלית) A method for combatting blackgrass in cereal crops and compositionsEnglish))therefore comprising a substituted triazine and substituted dinitroanilinehereby apply for a patent to be granted to me in respect thereof.•בהשת חלוקה — Application of Division •בקשת פטנט מוסף - Application for Patent Addition • דרישה דין קדימה Priority Claim מבקשת פטנט from Application No.......................................מם׳ dated.......... מיום • לבקשה / לפטנט to Patent / Appl. No........................................מס׳ dated..........................מיום מספר / סימן Number / Mark תאריך Date מדינת האגוד Convention Country • יפוי כח: כללי / מיוחד—רצוף בזה / עוד יוגש P.O.A.: general (Individual-attached / to be filed later-filed in case...................'............................הוגש בענין המען למסירת מסמכים כישראל Address for Service in Israel ד״ר א. דוד כהן ,.מכתשי ם...מפעלים..״?:ימי ים.בע״מ............................ ת,ד. 60 באר-שבע 84100 היום..........2.0...... בחודש.........July... שנת ״..19.82.of the year of ThisFor Office UseSignature of Applicantזיייך מ8רםוט; ז»ריד מחיתרט:3 0 JUN 986יBaWitatlJK ‘to*6-------------------—his from, impressed with the Seal of the Patent Office and indicating the number and. date of filing, certifies the filing of the pplication the particulars of which are set our above.Delete whatever is inapplicable 2= • מחק את המיותרA METHOD FOR COMBATTING BLACKGRASS IN CEREALCROPS AND' COMPOSITIONS THEREFOR COMPRISING ASUBSTITUTED TRIAZINE AND SUBSTITUTED DINITROANILINEThe present invention relates to a method for controlling weeds in cereal crops. More specifically, the invention relates to an economical method for achieving weed control in cereals, in-eluding control of black grass (Alopecurus myosuroides) with a synergistic combination of terbutryne and trifluralin.Grain fields such as wheat, barley, rye and oats etc, have often presented problems with respect to effective weed control״ This is particularly true for grain fields infested with A. myosuroides commonly known as black grass״. This weed is not easily controlled by the generally available herbicides, and those herbicides that do kill the weed are often phytotoxic to the cereal crops as well.A further consideration in weed control in general and of grain fields in particular is the great economic and technical advantage of applying herbicides before the emergence of the cultivated plants. The active herbicide is applied immediately after sowing and theweeds-are killed even in the germination. This enables unhindered growth of the cultivated plants which leads to considerable in-crease in the harvest.For this reason there has been an ever increasing demand for preemergence herbicides for cereal crops having high selectivity i.e. the ability to kill undesirable weeds while not injuring or retarding the growth of the crop.One such herbicide, terbutryne, 2-tert-butylamino-4-ethylamino-6--methylthio-l ,3,5-triazine,was disclosed for this purpose in Israel Patent 26950, and in fact it has been commercialized for this purpose. This herbicide is very effective in eliminating the most stubborn weed, black-grass, from cereal crops, including winter wheat.. However, this is the case only in fields having a low population of the blackgrass, below 60 flowering heads per square meter. In fields having higher populations of this weed the results are variable and not sufficiently effective at the recommended rates of 2.8 kg / ha. At higher rates of application the herbicide can adversely affect the cereal crop itself.More recent selective herbicides for this particular application have been claimed for example, in British patent 1,255,258. Thus,Chlprtoluron ?, (N-4-methyl-3-chlorophenyl N* ,N'-dimethyl urea), and isoproturon, (N-4-isppropylphenyl-N,N'-dimethyl urea), are con-sidered to be among the better • herbicides available today for the control of high populations of blackgrass. These, however, are rather expensive products and there exists a definite need for a more cost effective method of obtaining more effective weed control in cereal crops.One of the most successful and widely used herbicides to come on the market is trifluralin (2,6-dinitro-N,N-di-n-propy^^mtH'o^4-tri-fluoromethyl aniline).It is recommended for use in many crops including cotton, soybeans, cereals etc. and has found such wide applications that it has be-come almost a commodity herbicide in terms of tonnage and cost, However, trifluralin is not successful in destroying blackgrass,and it has therefore, not been recommended for this application.Being the popular herbicide that it is, trifluralin has been suggested to be used together with a host of other herbicides in synergistic mixtures. Thus, for instance, British patent 1,348,428 suggests combinations of 2,6-dinitroaniline herbicides with a) 5-halopyridazones, b) urea herbicides, c) s-triazine herbicides, and d) certain carbamates for protecting crop plants such as cotton, soybean, rape, rice and beets. Terbutryne is not disclosed by this patent. Nor does the patent recommend use of its combination for cereal crops, and certainly not for use against blackgrass.British patent 1,473,105 describes a special liquid herbicidal composition of trifluralin and linuron which is stated to be particularly useful in soil pre-emergence applications for cereals.Herbicidal mixtures with terbutryne are also known. Thus, for example, British patent No. 1,251,013 discloses the combinations of terbutryne and nitrofen as useful for controlling weeds in grain crops such as wheat, barley, rye, oats and maize. While this combination may be interesting theoretically it is not practical since nitrofen has been withdrawn from use for toxicological reasons.French patent 2,414,870 claims a three component synergistic herbicidal combination of a) a nitrophenoxy chlorophenyl etherb) a 2,6-dinitroani1ine and c) a urea derivative and / ord) a triazine compound. Specifically exemplified are combinations of nitrofen + trifluralin + terbutryne and trifluralin + linuron + terbutryne, In addition to the problem of toxicity of nitrofen as mentioned above, three component mixtures are more complex to work with and according to the patent hundreds if not thousands of mixture combinations are possible. None of the mixtures were exemplified against blackgrass and from the large number of possibilities, it is impossible to determine which, if any, 3 way combination would be suitable for this specific application.We have discovered that a mixture of terbutryne with trifluralin" in ratios of from 1:2 to 2.5:1 and preferably from 1.2:2 to 1:1, when applied preemergence to cereal crops at a rate of 1,0 to 4.5 and preferably 1.5 to 3.5 kg, per hectar, gives excellent weed control including control of blackgrass, even at high populations of the weed. This is particularly so in winter varieties of wheat and barley.Neither of these herbicides alone destroys blackgrass satisfactorily at high population rates, while at the same time avoiding injury to the cereal crops. It is only the combination of these two materials in the specified ratios and application rates that provides satisfactory results. The mechanism for this synergism is not clear, but it appears that the presence of trifluralin increases the effectiveness of smaller quantities of terbutryne in destroying high infestation of blackgrass and also increases the tolerance of cereal crops against injury by terbutryne. In effect this is a very highly selective herbicide combination for cereal crops in fields with high blackgrass populations. Based on the price structure of herbicides today, the inventive combin-ation offers satisfactory weed control in cereal crops, including blackgrass control, comparable to that provided by chlortol.uron, on a much more cost effective basis.The mixtures of this invention can be applied either separately or together. They can be in the form of wettable powders, solutions, emulsifiable concentrates, flowable concentrates or other formulated forms as are common in the industry. Preferably they are applied as a.single liquid formulation. Due to the differences in the physical and chemical properties of terbutryne and trifluralin, these herbicides are not readily formulated into stable 1iquid concentrates. Specific formulations have therefore, been developed using special solvents. Dimethyl formamide, for example, may be'used as one such solvent. Other solvent systems for this specific mixture are the subject of our copending application No. 66255.Therein, we disclose a solvent system consisting of 28 to 42% non-phytotoxic alicyclic ketone plus a stabilizing cosolvent selected from:1)   1 to 3% mesityl oxide, or2)   8 to 15% lower alkyl esters of C-18 unsaturated fatty acids ,or3)   a combination of 10 to 20% isophorone and1 to 3% di-lower alkyl formamide.Alicylic ketones which can be used are the cycloalkyl and cycloalkenyl ketones, especially cyclohexanone and cyclohexenone and their lower alkyl derivatives such as 2-methyl-cyclohexanone, 3-methylcyclo-hexanone, 3-methyl cyclohex-2-en-l-one, 3,5-dimethyl cyclohex-3-en-1-one, 2,6-dimethyl cyclohexanone, 2,2,6-trimethyl cyclohexanone, 3,3,5,5-tetramethyl cyclohexanone and 3,5,5-trimethylcyclohex-2-en-1-one. Cyclohexanone is most preferred.In addition to special solvents such liquid concentrate formulations also contain emulsifiers.The emulsifiers are generally anionic or nonionic emulsifiers, pre-ferably a mixture of these. Such mixtures are commonly used in the art of pesticide formulation. Examples of suitable anionicemulsifiers are alkali and alkaline earth metal salts of the alkyl and aryl sulfonates, alkyl benzene sulfates and sulfosuccinates such as octyl and nonyl phenyl sulfate, dodecyl benzene sulfonate, isopropyl naphthalene sulfonates, di octyl and di nonyl esters of sulfosuccinic acids. The preferred anionic emulsifiers are the calcium salts of alkyl benzyl sulfates and sulfonates, most preferably calcium alkyl benzene sulfates.IExamples(Of suitable non-ionic emulsifiers are fatty acid esters of polyoxyethylene sorbitan, alkylaryl polyethoxy ethanols such as octyl or nonyl phenyl polyethoxy ethanol, glyceride esters such as di glyceryl monooleate and ethoxy alkylphenols and cresols such as ethoxylates nonylphenol. The preferred nonionic emulsifiers are the ethoxylated alkyl phenols such as ethoxylated nonyl phenol.These emulsifiers are generally mixed in ratios of anionic to non-ionic from 3:7 to 7:3 and preferably about 1:1. The total amount of emulsifier is usually in the order of 5 to 15% of the liquid concentrate on a weight for weight basis. We have found that about 10% of a 1:1 emulsifier blend gives excellent liquid concentrates.The lower alkyl ester of a C-18 unsaturated fatty acid used as do-solvent, may be any 0ן to alkyl ester of C-18 unsaturated fatty acjd such as oleic acid, linoleic acid, tall oil fatty acids just to mention a few. Preferably, the methyl and ethyl esters are contemplated and most preferably methyl oleate.di-lower alkyl formamides suitable as cosolvents are the to di alkyl formamides, preferably dimethyl and diethyl formamides. Most preferred is dimethyl formamide.To demonstrate the effect of the inventive combination the followingexperiments were conducted.Example 1At Earl Colne, Essex England, fields infested with 228 heads per square meter of blackgrass were sown with winter wheat during the autumn of 198.1. The fields were treated preemergence with a 1.5:2 mixture of terbutryne and trifluralin at rates of 1.7 kg / ha and 2.1kg / ha active•ingredients respectively.• In both cases the reduction of heads of blackgrass was 96 percent compared with an untreated field.Example 2Fie'ld tests conducted during the autumn of 1981 at Houghton, NottsEngland, on plots having a blackgrass infestation of 116 heads per square meter, gave the following results:Composition Terbutryne kg / ha Trifluralin kg / ha %' Reduction of blackgrass heads XDamage wheat A 1.5 2.0 80 None B 1.8 2.4 81 None . C 2.0 1.0 64 None D 2.0 1.2 75 .None E 2.5 1.0 76 None F 2.5 1.2 80 None Chlortoluron (3.6 kg / ha) - - 87 None Example 3Plots of wheat were sown in Cottingham, Lincs England, during the autumn of 1981 and treated pre-emergence with mixtures of terbutryne and trifluralin. The plots had 267 heads of blackgrass per square meter prior to treatment. The following results were obtained.Composition Terbutryne kg / ha Tri fluralin kg / ha % Reduction of Blackgrass heads %Damage wheat A 1.5 2.0 89 None B 1.8 2.4 94 None C 2.0 1.0 72 None D 2.0 1.2 70 None E 2.5 1.0 83 None F 2.5 1.2 91 None Chlortoluron 88 None (3.6 kg / ha) These experiments demonstrate that the mixtu.es of terbutryne-tri-fluralin at the ratios used,control blackgrass without adversely affecting the wheat crop.The mixtures of this invention control weeds by root action and work best under good growing conditions. They will remain active in the soil for several months after application when initial weed control has been successful. / 9 / 5 EXAMPLE kA mixture of trifluralin and terbutryne in a ratio of 2:1.5 was compared for pre-emergence weed control with similar mixtures as set forth below.9cm pot were sown with 25 seeds of the weed Aiopecurus Myosuroides using 50% loam, 50% general purpose compost mixture. The pots were placed in trays and dept in a glass-house at minimum temperature of H deg.C. Applications of treatments were made'' with a single pass using a Azo Van der Wey portable sprayer fitted with Birchmeier 1.6mm. helio saphire nozzles. The volume of application were 200 1 / ha in all cases, sprayed at a pressure of 2.2 KgF / cm. After spraying, the pots were kept out of doors for thirty minutes, before being returned to the glass-house, where the pots were assembled randomly into replicates. All treated pots and control were watered 2^1 hours after spraying.Percentage germination was obtained by counting the seedlings in each pot, and comparing this with the number of seeds planted. Vigour and phtotoxicity were assessed over the following 26 days by using a visual assessment scale based on the following code: 0 - completely dead1 - Moribund, but not totally dead.2 - Alive, but unlikely to make further growth.3 ־ Very stunted, but apparently make some growth.k - Considerable loss of growth with dead tissue.5 ־ Readily distinguishable loss of growth with dead tissue starting to appear.6 - Reduced growth with initial signs that tissue is starting to die.1 - Slight reduction in growth,epinasty and other morphological abnormalities.8 - Some detectable adverse effects compared to the control such as colourdifference and si ight prostration.9 ־ Indistinguishable from control.The following results were obtained:׳0Per Cent        Days after treatmentT reatment Germination 11', 21 22 26 y Control 50 9 9 9 9 Tri f lural in 0.57 36 9 7 2.5 2 + Terbutryne 0.43 Tri fluralin 0. 5 + Terbutryne 0.25 48 9 7.5 3.5 3 Nitrofen 0.25Tri fluralin 0.25Terbutryne 0.25 50 ' 9 8 5 4 + L i n u ron 0. 5 * From these results it can be concluded that germination of Alopecurus Mysouroides was reduced the most by the mixture of Trlfluralin + Terbutryne. The highest level of control was given by this same combination with unlikelihood of further growth. The least effective treatment was thecombination of Trifluralin + Terbutryne + Linuron.Some of the weeds controlled by the inventive method are:Annual meadow grassRough meadow grassBlack bindweedCharlockCommon chickweedCommon Field-speedwellCommon FumitoryCommon Mouse-earCommon OracheCommon PoppyCorn ChamomileFat HenFool's ParsleyGroundselHenbit dead-nettleIvy-leaved SpeedwellParsley PiertPinappleweedRed Dead-nettleRedshankScentless MayweedShepherd's PurseAnnual NettleWild RadishVenus's-looking-glassBlackgrassCleaversFlaxweedKnotweedfca annuaRoa t.ri viallsPo.! yyonuiir convol ul usSlnaj>is arvenisStel1 aria mediaVeronica agrestisFumaria officinalisCerastium arvenseAtripl ex pa tulaPa pa ver spp.Anthemis ArvensisChenopodium albumAethusa cynapiumSanncio vulgarisLamium amplexicauleVeronica heteraefoliaAphanes arvensisMatricaria matricariodesLamium purpureumPolygonum persicariaMatricaria maritimumCapsella bursa-pastorisUrtica urensRaphanus raphanistrumSpecularia perfoliataAlopecurus myosuoidesGalium aparineLinumPolygonum aviculare-13’ -

Claims

We Claim:

1. A method for obtaining satisfactory weed control in cereal crops, including control of blackgrass^without injury to the cereal crops, comprising preemergent application of a mixture of terbutryne and trifluralin having a ratio of 1:2 to 2.5:1 in sufficient amount to control the undesire-able weeds and yet not injure the crops.

2. A method in accordance with claim 1, wherein the ratio of terbutryne to trifluralin is from 1.2 :2 to 1:1.

3. A method in accordance with claims 1 and 2, wherein the rate of application of the mixture is from 1.0 to 4.5 kilogram per hectar.

4. A method in accordance with claims 1 to 3, wherein the rate of application is 1.5 to 3.5 kg / ha.

5. A method in accordance with claims 1 to 4, wherein the cereal crop is winter wheat.

6. A method in accordance with claims 1 to 5 wherein the black-grass population is greater than 60 heads per sq.meter.

7. A method in accordance with claims 1 to 6,wherein theratio of terbutryne to trifluralin is substantially 1.5to 2.0 and the rate of application is between 1.75 to 3.5kg / ha.

8. A composition for use in controlling weeds in cereal crops, including blackgrass, comprising a mixture of terbutryne and trifluralin having a ratio of 1:2 to 2.5:1.FOR THE APPLICANTS: