GB2126092A - Synergistic herbal composition - Google Patents

Abstract

A synergistic herbicidal composition comprises as active ingredient (i) ethalfluralin and (ii) terbuthilazine, terbutryn or terbumeton at a ratio of 19:1-1:4 parts by weight. The synergistic composition can be advantageously used for pre- emergent and post-emergent weed control in field plant cultivation, particularly in autumn wheat. The compositions accelerate the destruction of weeds and are suitable for pre-emergent application and thereby create highly favourable conditions for the growth of autumn wheat and this leads to an increase of crop yield.

Description

SPECIFICATION Synergistic herbicidal composition The invention relates to a synergistic herbicidal composition containing a mixture of a compound of formula I below and a compound of formula II in which Xis chlorine, methylthio or methoxy.

The compositions of the present invention can be advantageously used for pre-emergent and post-emergent weed control for field plants, particularly in autumn wheat.

In Hungary autumn wheat is cultivated on an area of about 1,2 million hectares and for the time being about 95% of this crop is subjected to chemical weed control. According to present practice the herbicide is applied at 3-5 leaved stage of the autumn wheat or later in the period between growing into a bush and shoot up, i.e. post-emergent treatment is carried out in spring. Recently pre-emergent and post-emergent treatment in autumn has become widespread and this can be of large importance in the increase of crop yield. Weed control is generally carried out in spring because the optimal selectivity and activity of the available herbicides (hormonal herbicides e.g. MCPA, MCPP, 2,4-D, 2,4 DP, dikamba, fluorenol; and contact herbicides e.g. bentazon, bromphenoxime) fall between the time between the growing into bush and shoot up.It is known that said herbicides are effective only against broad-leaved weeds and are even inactive against numerous weeds belonging to this group.

If these herbicides are used for a number of years, resistant weeds are selected which proliferate.

Thus e.g. the amount of Centaurea cyanus L., Cirsium arvense L. Scop., Consolida spp., Sinapis arvensis L., Papaver rhoeas L. and Raphanus raphanistrum L. has decreased and been replaced by the following weeds having T, and T2 life-form.

T1 Capsella bursa-pastoris L. Medic. shepherd's purse Lamium amplexicaule L. henbit Lamium purpureum L. red dead nettle Myosotis arvensis L. Hill common forget-me-not Spergula arvensis L. corn spurrey Stellaria media L. Cyr. chickweed Veronica hederifolia L. ivy leaved speedwell Veronica persica Poir. buxbaum's speedwell Veronica polita Fr.

T2 Adonis aestivalis L. summer adonis Anthemis arvensis L. corn chamomile Anthems cotula L. stinking mayweed Galium aparine L. catchweed Lithiospermum arvense L. cromweel corn Matricaria chamomilla L. common chamomille Thlaspi arvense L. field pennycress Viola arvensis Murr. russian vetch heart's ease In the past years monocotyledonous weeds have appeared and become widespread in large areas of Hungary and the control of these weeds has caused serious problems. From these weeds Alopecurus myosuroides Huds. (black grass) and Apera spicaventi L. P.B. (silky bent grass) germinating also in autumn can be mentioned. Attempts were made for the control of said weeds in autumn and early spring with the aid of pendimetalin, chlorotoluron and isoproturone containing compositions.

While the said herbicides show good activity against the above monocotyledonous weeds, they are not sufficiently effective against numerous dicotyledonous species (e.g. Capsela bursa-pastoris L. Medic., Viola arvensis Murr. and Veronica hederifolia L.). It is well known that similarly to other cultivated plants autumn wheat is the most sensitive to damages caused by weeds at the early stage of growth and for this reason the elimination of the juvenile weed composition is of significant importance in the increase of crop yield. It is also known that in wheat sown in the optimal sowing period -- i.e. at the end of September or the beginning of October -- the above-mentioned weeds of the T, and T2 lifeform shoot in autumn.If said weeds are controlled still in autumn or at the end of winter or in early spring time, they can no more inhibit the growth of wheat and the growing into bush and consequently a larger crop yield can be achieved.

The object of the present invention is to provide a herbicidal combination which can be used both in autumn and spring and possesses such a wide spectrum of effect which enables the control of both mono- and dicotyledonous weeds without any adverse toxical effect on autumn wheat.

In the course of our tests we have obtained surprising results. Thus herbicides which have not been used so far in combinations, provided to be highly suitable for achieving the desired object. Thus reference is made to Edition 6 of "The Pesticide Manual" (edited by C. R. Worthing, London, 1979).

According to page 240 of said Manual the compound of the Formula I [i.e. N-ethyl-N-(2-methallyl)-2,6 dinitro-4-trifluoromethyl-aniiine, etalfluralin] is suggested for use in weed control on cotton, bean and soya to be incorporated into the soil at a dose of 1.0-1.25kg/ha. According to page 502 the compound of the general Formula II wherein X is chlorine (i.e. 2-tertiary butylamino-4-chloro-6ethylamino-1 ,3,5-triazine, terbutilazin) is suggested for use as selective herbicide in cultures of maize, grape and lemon-species in a dosage of 1.2-1.8 kg/ha.According to page 503 the compound of the general Formula II, wherein X is methylthio (i.e. 2-tertiary butylamino-4-ethylamino-6-methylthio1 ,3,5-triazine, terbutrin) is suggested to be used as pre-emergent herbicide in autumn wheat, sunflower, sugar cane and bean cultures and also as post-emergent herbicide in maize and a dosage of 1-2 kg/ha. According to page 501 the compound of the general Formula II, in which Xis methoxy (i.e. 2-tertiary butylamino-4-ethylamino-6-methoxy-1 ,3,5-triazine, terbutemon) is suggested for use as post-emergent herbicide in lemon-species, apple and grape plantations in a dose of 3-10 kg/ha.

It is well-known that said herbicides possess per se a narrow spectrum of effect. According to prior art references only terbutrin is suggested to be used as pre-emergent herbicide in autumn wheat but in practice this herbicide is not commonly used either. For the other compounds there is no reference in the prior art as to the use thereof according to the present invention. Moreover it has not been hitherto known that etalfluralin can be used for weed control successfully in wheat without incorporating the same into the soil, i.e. before the emergence of the weeds or until a 2-3 leaved stage of the plant.

It has been found that the above compounds can be used as selective pre-emergent herbicide until the wheat reaches the 2-3 leaved stage. Thereafter synergistic effect has been tested on weeds which are known to be tolerant to the said components. It has been surprisingly found that combinations of etalfluralin of the Formula I with any compound of the general Formula II at a certain ratio, show a significant surplus-effect against the weeds. In the tests we have also defined the synergistic ratio of the components.

The synergistical compositions of the present invention contain conventionally used carriers, excipients and other additives. The total active ingredient content of the composition amounts to 0.185% by weight and the ratio of the compound of the Formula I to the compounds of the general Formula II (wherein X is chlorine, methylthio or methoxy) is between 19:1 and 1:4, preferably between 4:1 and 1:1.

The compositions of the present invention may be in the form of aqueous solutions, solutions in an organic solvent, solutions comprising mineral oil, solution concentrates emulsifiable in water, powdered compositions forming stable suspensions with water, powder mixtures, aqueous and oily emulsions, aqueous suspension concentrates, aqueous pastes and granules. The compositions may comprise solid carriers, e.g. natural and/or synthetic substances of organic and/or inorganic origin, such as finely powdered mineral or vegetable substances, plastics, silicates, magnesium oxide etc. As liquid carrier e.g. water or liquid aliphatic or aromatic hydrocarbons and derivatives thereof (e.g. aliphatic and aromatic alcohols, ketones, esters, halogenated derivatives etc.) can be used.As auxiliary agents and other additives e.g. wetting agents, dispersing agents, surfactants (e.g. nonionic or and/or anionic tensides, lignine sulfone acid derivatives), adhesion promoting agents, evaporation inhibiting agents, stabilisers, etc. can be used. The concentrates having a high active ingredient content are diluted prior to use to the desired concentration and applied onto the field by means of a suitable equipment.

The advantage of the synergistic compositions of the invention resides in the fact that they solve an important and serious problem of agriculture, namely the effective control of a wide range of monoand dicotyledonous weeds in autumn wheat without causing any substantial damages to the said cultivated plant. The compositions of the present invention accelerate the weed killing and are also suitable for pre-emergent application and thus create favourable conditions for the growth of autumn wheat and thereby give rise to an increase of the crop yield. A further advantage of the invention is that it enriches the scope of available herbicides by a new, highly efficient, wide-spectral and safe plant protecting agent.

Further details of the present invention are to be found in the Examples without limiting the scope of the invention to the said Examples.

Example 1 A series of solutions which can be sprayed directly without dilution is prepared by using a 30:70 parts by weight mixture of N-methyl-pyrrolidone and ethanol as solvent, a polyoxyethylene sorbitane monolaurate surfactant and N-ethyl-N-(2-methallyl)-2,6-dinitro-4-trifluoromethyl-aniline (etalfluralin) and 2-tertiary butylamino-4-chloro-6-ethylamino- 1 3,5-triazine (terbutilazin) as active ingredients. The ratio of the two active ingredients is 0.4:1.6; 0.7:1.3; 1.0:1.0; 1.3:0.7; 1.6:0.4 and 1.9:0.1, respectively and the total active ingredient content amounts to 20% by weight.Series of solutions comprising only one active ingredient are also prepared by using the above solvents and surfactant so that the active ingredient content of each solution should be identical with the amount of the active ingredient being present in the composition containing two active ingredients. The solutions thus obtained are used for tests in glass-house on Triticum aestivum ssp. vulgare (autumn wheat) as cultivated plant and Capsella bursa-pastoris, Viola arvensis, Veronica hederifolia, Apera spica-venti and Alopecurus myosuroides as weeds of T, and T2 life-form. After sowing and covering the seeds of the surface of the soil is sprayed with the compositions corresponding to the active ingredient doses disclosed in Table 1. The symptoms of weed killing are evaluated 14 days after treatment. The results are enumerated in Table 1.The above data are evaluated according to the method of Colby (Weeds, January 1 967, pages 20-22) and the synergistic and antagonistic data are set forth in Table 2.

It can be seen from Table 2 that in case of each tested active ingredient ratio synergism can be detected. In all the tested weed species the strongest synergism is obtained when using etalfluralin and terbutilazin at a ratio of D2+A3, D3+A2 and D4+A1, respectively.

Table 1 Activity of etalfluralin (D), terbutilazin (A) and a mixture of etalfluralin+terbutilazin (D+A) 14 days after treatment (weed control, %) Triticum Active Dose Capsella Viola Veronica Apera Alopecurus aestivum ssp.

ingredient kg/ha bursa-pastoris arvensis hederifolia spica-venti myosuroides vulgare D0 0.4 10 - 20 - - D1 0.7 36 - 28 - - D2 1.0 40 - 32 - - D3 1.3 52 - 41 10 10 D4 1.6 63 - 58 30 30 D5 1.9 95 5 68 40 35 10 A0 0.1 25 5 30 - - A1 0.4 28 16 32 - - A2 0.7 33 28 38 - - A3 1.0 38 41 46 - - A4 1.3 55 60 52 - - A5 1.6 68 70 65 - - A6 1.9 82 78 80 - - D0+A5 0.4+1.6 90 72 80 30 10 D1+A4 0.7+1.3 88 75 82 36 20 D2+A3 1.0+1.0 90 79 83 62 30 D3+A2 1.3+0.7 100 100 98 88 85 D4+A1 1.6+0.4 100 98 92 85 93 D5+A0 1.9+0.1 100 92 79 80 82 Table 2 Synergistic and antagonistic (-) effect achieved with the combinations (%) Triticum Active Dose Capsella Viola Veronica Apera Alopecurus aestivum ssp.

ingredient kg/ha bursa-pastoris arvensis hederifolia spica-venti myosuroides vulgare D0+A5 0.4+1.6 18.8 2.0 8.0 30.0 10.0 D1+A4 0.7+1.3 16.8 15.0 16.6 36.0 20.0 D2+A3 1.0+1.0 27.2 38.0 19.7 62.0 30.0 D3+A2 1.3+0.7 32.2 72.0 36.6 78.0 75.0 D4+A1 1.6+0.4 26.6 82.0 20.6 55.0 63.0 D5+A0 1.9+0.1 3.75 82.25 1.4 40.0 47.0 - Example 2 A series of powders forming a readily sprayable stable suspension in water is prepared by using China clay and silicic acid anhydride as carrier, sodium lignine sulfonate and fatty alcohol sulfonate as auxiliary agent and N-ethyl-N-(2-methallyl)-2,6-dinitro-4-trifluoromethyl-aniline (etalfluralin) and 2tertiary butylamino-4-ethylamino-6-methylthio-1 ,3,5-triazine (terbutrin) as active ingredients.The total active ingredient of the compositions amounts to 50% by weight while the ratio of the two components is that disclosed in Example 1. Series of solutions comprising only one active ingredient are also prepared in which the active ingredient content is the same as the amount of the active ingredient in caption being present in the composition containing two active ingredients. From the said compositions sprays are prepared by diluting with water. The spraying test described in Example 1 is carried out by using the sprays thus obtained in doses disclosed in Table 3. The results thus obtained are summarized in Table 3. The synergistic and antagonistic effect is calculated by the method of Colby and set forth in Table 4.

It appears from Table 4 that the highest synergistic activity is measured for all weeds in the case of etalfluralin+terbutrin combinations D2+B3, D3+B2 and 04+ B1, respectively.

Table 3 Activity of etalfluralin (D), terbutrin (B) and mixtures of etalfluralin+terbutrin (D+B) 14 days after treatment (weed control, %) Triticum Active Dose Capsella Viola Veronica Apera Alopecurus aestivum ssp.

ingredient kg/ha bursa-pastoris arvensis hederifolia spica-venti myosuroides vulgare D0 0.4 10 - 20 - - D1 0.7 36 - 28 - - D2 1.0 40 - 32 - - D3 1.3 52 - 41 10 10 D4 1.6 63 - 58 30 30 D5 1.9 95 5 68 40 35 10 B0 0.1 5 5 20 - - B1 0.4 33 20 35 - - B2 0.7 42 35 55 - - B3 1.0 64 55 60 - - B4 1.3 80 72 65 10 25 10 B5 1.6 95 85 70 15 48 15 D0+B5 0.4+1.6 100 100 94 50 50 30 D1+B4 0.7+1.3 85 98 92 36 50 50 30 D2+A3 1.0+1.0 92 95 88 65 68 D3+B2 1.3+0.7 100 92 98 95 90 D4+B1 1.6+0.4 100 68 90 95 98 D5+B0 1.9+0.1 100 42 86 90 90 Table 4 Synergistic and antagonistic (-) effect achieved with the combinations (%) Triticum Active Dose Capsella Viola Veronica Apera Alopecurus aestivum ssp.

ingredient kg/ha bursa-pastoris arvensis hederifolia spica-venti myosuroides vulgare D0+B5 0.4+ 1.6 4.5 15.0 18.0 35.0 -2.0 -15.0 D1+B4 0.7+1.3 -2.2 26.0 17.2 40.0 25.0 -12.0 D2+B3 1.0+1.0 13.6 40.0 15.2 65.0 68.0 D3+B2 1.3+0+7 27.8 57.0 24.6 85.0 80.0 D4+B1 1.6+0.4 24.8 48.0 17.3 68.0 65.0 D5+B0 1.9+0.1 4.75 32.25 11.6 50.0 55.0 - Example 3 A series of water emulsifyable concentrates is prepared by using cyclohexanone, butyl acetate and isobutanol (3:1:1) as solvent, alkyl aryl sulfonate and polyethylene alkyl phenol (2:3) as surfactant and N-ethyl-N-(2-methallyl)-2,6-dinitro-4-trifluoromethyl-aniline (etalfluralin) and 2-tertiary butylamino-4-ethylamino-6-methoxy-1 ,3,5-triazine (terbumeton) as active ingredient.The total active ingredient content of the compositions amounts to 40% by weight and the ratio of the active ingredients is that disclosed in Example 1. Series of dilutions comprising only one active ingredient are also prepared in which the active ingredient content is the same as the amount of the active ingredient in caption being present in the composition containing two active ingredients. From the said compositions sprays are prepared by diluting with water. The spraying test described in Example 1 is carried out by using the compositions in doses set forth in Table 5. The results obtained are summarized in Table 5. The synergistic effect caiculated therefrom by the method of Colby is disclosed in Table 6.

It appears from Table 6 that for all the tested weeds the highest synergistic activity is obtained by using etalfluralin+terbumeton combinations of D2+C3, D3+C2 and D4+C1, respectively.

Table 6 Activity of etalfluralin (D), terbumeton (C) and mixtures of etalfluralin+terbumeton (D+A) 14 days after treatment, (weed control, %) Triticum Active Dose Capsella Viola Veronica Apera Alopecurus aestivum ssp.

ingredient kg/ha bursa-pastoris arvensis hederifolia spica-venti myosuroides vulgare D0 0.4 10 - 20 - - D1 0.7 36 - 28 - - D2 1.0 40 - 32 - - D3 1.3 52 - 41 10 10 D4 1.6 63 - 58 30 30 D5 1.9 95 5 68 40 35 10 C0 0.1 15 - 18 - - C1 0.4 20 - 22 - - C2 0.7 20 15 31 - - C3 1.0 25 20 34 - - C4 1.3 40 36 40 - - C5 1.6 56 44 59 - - C6 1.9 66 54 75 - 20 26 D0+C5 0.4+1.6 80 75 71 25 21 D1+C4 0.7+1.3 90 80 74 30 33 D2+C3 1.0+1.0 98 90 88 32 46 D3+C2 1.3+0.7 100 95 93 65 68 D4+C1 1.6+0.4 100 90 90 65 70 D5+C0 1.9+0.1 95 90 74 61 62 Table 6 Synergistic and antagonistic (-) effect achieved with the combinations (%) Triticum Active Dose Capsella Viola Veronica Apera Alopecurus aestivum ssp.

ingredient kg/ha bursa-pastoris arvensis hederifolia spica-venti myosuroides vulgare D0+C5 0.4+1.6 19.6 31.0 3.8 25.0 20.0 D1+C4 0.7+1.3 28.4 44.0 17.2 30.0 33.0 D2+C3 1.0+1.0 43.0 80.0 32.9 32.0 42.0 D3+C2 1.3+0.7 38.4 80.0 33.7 55.0 58.0 D4+C1 1.6+0.4 29.6 90.0 22.8 35.0 40.0 D5+C0 1.9+0.1 -0.75 85.0 0.2 21.0 27.0 -

Claims (6)

Claims

1. A herbicidal composition which comprises as active ingredient (I) ethalfluralin and (II) terbuthylazine, terbutryn or terbumeton at a ratio of 19:1-1:4 parts by weight.

2. A composition as claimed in claim 1, wherein the ratio of Compound i to Compound II is 4:11:1.

3. A composition as claimed in claim 1 or claim 2 which contains 0.1-85% by weight of the compounds I and II.

4. A composition as claimed in any one of the preceding claims in the form of a solution, suspension or emulsion or concentrate for the preparation thereof.

5. A composition as claimed in claim 1 substantially as described herein in any one of the Examples.

6. A method of pre-emergent or post-emergent weed control in field plant cuitivation comprising applying to the site a composition as claimed in any one of the preceding claims.