IE48948B1 - Herbicidal compositions - Google Patents

Abstract

1. Herbicidal composition containing as active ingredient a combination of a compound of the formula A see diagramm : EP0009716,P7,F1 with a compound of the formula B see diagramm : EP0009716,P7,F2

Description

This invention relates to a herbicidal composition containing as active ingredient a combination of 2,6-dinitro-N, N-dipropyl-'t-trifluoromethylaniline (common name trifluralin) of the formula with 3-(4-isopropylphenyl)-1,1-dimethyl urea (common name isoproturon) of the formula CH. (i}H7C3"Ο NH—CO—Ν' CH.

Isoproturon Both active compounds are known, for example from H. Martin and C.R.Worthing Pesticide Manual, 5th edition. 1977, British Crop Protection Council, pages 528 and 317.

It is also known to use the two compounds in cereals, for example from A.J.Kovacs and C.Mallegni: Proc. 10th British Weed control Conf., 1970, pages 56 to 62 and J.Rognon, A.Thizy and D.Pillon: 23ieme Symp. de Phythoparmacie Gent 1972, pages 663 to 669.

It has now been found that a combination of components A and B are characterized by a synergistic effect in the cor. trol of weeds in crop plants, especially wheat, barley and rye. This effect is surprising and could not have been expected in view of prior publications.

Components A and B can be combined with each other in a wide range. Mixing proportions of A;B of 10:1 to 1:10 - 3 and preferably 4:1 to 1:4 proved to be especially advantageous.

The compositions according to the invention can be used to combat successfully a great number of weeds in crop cultivations, especially in cereals such as wheat, barley and rye. The following weeds are named by way of example: Gramineae Alopecurus myosuroides Avena fatua Poa annua Poa trivialis Lolium multiflorum Compositae Matricaria inodora Matricaria chamomilla Anthemis arvensis Papaveraoeae Papaver rhoeas Cruciferae Capsella bursa-pastoris Sinapis arvensis Rubiaceae Galium aparine Scrophulariaceae Veronica arvensis Veronica hederifolia Labiatae Lamium purpureum Caryophyllaceae Stellaria media Polygonaceae Polygonum persicaria Polygonum aviculare The combination of active ingredients according to the invention can be used in the form of a tank mixture prepared by mixing the active components directly prior to application or as formulations ready for use. Such formulations are especial29 ly wettable powders, emulsifiable concentrates or granules 8 9 4 8 - 4 which, besides the combination of active compounds, contain the usual formulation auxiliaries such as wetting agents, adhesives, dispersing agents, solid or liquid inert materials, grinding auxiliaries, solvents and emulr> sifiers.

Wettable powders of a combination of active compounds according to the invention can be prepared, for example, by first melting compound A (trifluoralin) in a heating chamber at 80°C and atomizing and adsorbing the warm mol1° ten active compound in a rapid mixer (of the type Lodige mixer), for example on finely disperse, synthetic silicic acid or another absorptive inert powder, such as diatomaceous earth, clay, or bentonite, while mixing in a manner to obtain a loose and dry powder. To obtain a formulation having a high concentration of active substance synthetic (R) silicic acid is preferred, for example Wessalon' 'S of (R) Messrs. Degussa, Federal Republic of Germany or Neosyl of Messrs. Crosfield Chemicals, England.

Simultaneously, a powder concentrate is prepared from compound B (isoproturon) by mixing and grinding the compound together with the usual formulation and grinding auxiliaries, for example or; a rapid high power mill such as a pin mill, blowing mill cr an air jet mill, until the powder has a fineness preferably of 325 meshes. This means that when the powder is passed through a 44 micron sieve the particles must have a diameter below 44 microns except for a residue of at most 1 ί by weight. Prior to grinding the powder concentrate is preferably mixed with the necessary dispersing ar.d wetting agents, defoamers and inert mate4 8 9 18 -5fi al.·;.

Suitable dispersing agents are, for example, sodium dinaphthylmethane disulfonate, lignosulfonates, condensation products of alkylnaphthalene-sulfonic acids with ere5 sols, sodium sulfite and formaldehyde (dispersant SS of Messrs. Hoechst AG), oleyl-N-methyl taurides, polyvinyl alcohols, polyvinyl pyrrolidor.es, and suitable wetting agents are, for example, alkylnaphthalene sulfonates, alkylsulfosuccinie acid esters, alkylbenzene sulfonates and alkyl sul10 fonates. Suitable defoamers, if any, are for example, sodium and potassium salts of fatty acids and silicones.

The separately produced trifluralin and isoproturon powder concentrates are mixed in the desired active substance proportions. The wettable trifluralin-isoproturon powder obtained is then milled once more in a simple cross beater mill or high power mill with reduced speed of rotation of the mill rotor.

The wettable powders obtained are formulations which are uniformly dispersible in water and which contain, in addition to the active compounds and a diluent or inert material, wetting agents, for example polyoxethylated alkylphenols, polyoxethylated oleyl or stearyl amines, alkyl- or alkylphenyl sulfonates as well as dispersing agents, for example sodium lignosulfonate, sodium 2,2'-dinaphthyl25 methane-6,6'-disulfonate, sodium dibutylnaphthalene sulfonate or the sodium salt of oleoylmethyl taurine, and optionally an adhesive, for example polyvinyl alcohols, and grinding auxiliaries.

Emulsifiable concentrates are obtained by dissolving 8 9 4 8 - 6 the .-icfive substance in an organic solvent, for example butane I , eye 1. hexunone, dimethyl formamide, xylene or higher boiling aromatics and adding, for example, a non ionic emulsifier and wetting agent, for example a polyethy5 lated alkylphenol or a polyoxethylated oleyl or stearyl amine.

Dusts are obtained by grinding the active components with finely divided, solid substances such as talc, natural clays such as kaolin, bentonite, pyrophillite or diatomace10 ous earth.

Granules can be prepared by atomizing the active components onto an absorptive, granular inert material or by applying active substance concentrates by means of an adhesive, for example polyvinyl alcohol, sodium polyacrylate or also mineral oils, onto the surface of a carrier material such as sand, kaolinite or a granular inert material. Granules can also be produced in a manner usual for the manufacture of granular fertilizers, if desired in admixture with fertilizers.

In the herbicidal compositions the concentration of the active compounds in the commercial formulations may vary. In wettable powders the active compound concentration varies, for example, between about 10 and 80 ? by weight, the remainder up to 100 J by weight consisting of the abovemen25 tioned formulation additives. In the case of emulsifiable concentrates the active substance concentration is about 10 to 70 % by weight. Dust formulations usually contain about 5 to 20 ? by weight of active substance and sprayable solu29 tions about 1.05 to 20 ? by weight. In the case of gra48948 - 7 nules the active substance content in part depends on whether it is ir. a liquid or solid state and what granulating auxil iirir:.-., filler.-, and the like are used. In general, it is from about 10 to 80 J by weight.

The commercial concentrates are optionally diluted prior to application in the usual manner, for example by means of water in the ease of wettable powders and emulsifiable concentrates. Granular formulations generally need not be diluted with further inert material prior to use.

The amount of active substance necessary for obtaining the desired result depends on external conditions such as temperature, humidity and the like. It can vary within wide limits, for example in the range of from 0.1 to 10.0 kg/ha and preferably from 0.5 to 5 kg/ha of active substance (AS).

The following examples illustrate the invention.

EXAMPLES OF FORMULATION Preparation of a trifluralir.-isoproturor. wettable powder a) Trifluralin concentrate 200 kg of industrial grade trifluralin (95 % puri20 ty) are melted at 80°C in a heating chamber and the molten mass is sprayed in a rapid mixer having a capacity of 3 cubic meters (type Lodige) by means of a distributor rake with running engine onto 3**0 kg of finely disperse silicic acid (Wessalon S). Mixing is cor.tinu25 ed for 15 minutes whereupon a finely powdered adsorbate is obtained. b) Isoproturor. concentrate 202.50 kg of isoproturor. (technical grade 99 ? purity) 67.00 kg of finely disperse, synthetic silicic acid 8 9 18 - 8 (Wf-snalf n S) 113.50 kg cf the condensation product of alkalnaphthalene-suifonic acid with cresols, sodium sulfite and formaldehyde (Dispersant SS of Messrs Hoechst) ( R) 52.10 kg of sodium alkylnaphthalene sulfonate (v 'Leonil DB) 1.40 kg of soap flakes and 13-40 kg of sodium carbonate are mixed and the mixture is milled once ir. a blowing mill on a 0.5 mm triangular sieve to a fineness below 44 microns. c) Isoproturon-trifluralin 20:20 wettable powder To produce the wettable powder 550 kg of the trifluralin concentrate prepared as described sub a) and 450 kg of isoproturon concentrate prepared as described sub b) are mixed and the mixture is milled in a cross beater mill at a external circumferential speed of the milling cross of about 80 meters per second through a 0. mm punched screen.

By screening through a 44 micron sieve at most 1 % by weight of residue is separated. The resulting wettable powder has a suspendability of 80 % after standing for 30 minutes in water of 30°C of a standard hardness of 3^2 ppm.

The wettable powder has the following composition: 21.00 ? by weight of industrial grade trifluralin of a purity of 95 ί, corresponding to 20 ? by weight of pure trifluralin .25 ί by weight of industrial grade isoproturon of a 489 48 - 9 purity of 99 ¢, corresponding to 20 Ϊ by weight of pure isoproturon 40.70 ? by weight of finely disperse synthetic silicic acid (Wessalon S) 11.35 ? by weight of a condensation product of alkylnaphthalene-sulfonie acid with crescls, sodium sulfite and formaldehyde (dispersant SS of Messrs. Hoeehst AG) .21 ί by weight of sodium alkylnaphthalene sulfonate 10 ((R)Leor.il DB) 0.14 ί by weight of soap flakes and 1.35 ί by weight of sodium carbonate.

EXAMPLE 2: A tank mixture is obtained by first mixing with water 15 a commercial wettable powder having a content of 75 ί weight of isoproturon as active substance and a commercial emulsifiable concentrate having a trifluralin content of 48 % by weight, in a active substance proportion of 1:1 and then diluting the mixture obtained to give a spray liquor. The spray liquor is applied in an amount of about 100 to 600 liters per hectare.

In analogous manner, spray liquors are prepared with different active substance proportions and applied in the same amount.

Proportions of B:A of from 4:1 to 1:4 are preferred.

BIOLOGICAL EXAMPLES The following Example I is carried out in the greenhouse. Ir. all cases the calculated and the found efficier.29 cy of the combination is given, the calculated value being 89 48 - 10 indicated in brackets before the found values. The calcu1.,1..1 ι I Γι<· ι <-ι:··ν ι:; <1·· term i rn-d according to the formula of S.R. Colby in Calculation of synergistic and antagonistic responses of herbicide combinations, Weeds 15 (1967) pages to 22. The formula is as follows in which X denotes the percentage of damage by herbicide A when applied in a concentration of x kg per hectare Y denotes the percentage of damage by herbicide B when applied in a concentration of y kg per hectare E is the degree of damage to be expected by herbicides A + B in a concentration of x + y kg per hectare.

If the actual damage is greater than the damage to be expected according to the calculation, the combination has a more than additive effect, i.e. it has a synergistic effect.

EXAMPLE I: In the greenhouse various weeds are sown in pots and the seeds are covered with a thin layer of soil. On the very same day the surface of the soil is sprayed with compounds A and B individually in the indicated doses ar.d with combinations of the two compounds. 4 Weeks after the treat ment the results are evaluated. They are summarized in the following Table. It can be seen that the combinations have a distinctly better effect on some weeds than was to be expected according to the above formula, in other words, they had a synergistic effect. 8 9 4 8 - 11 Table I Effect cf the compounds A and B individually (damage in ί) and of the combinations in the indicated doses (mg of active substance (AS) per pot) on the weeds specified sub 1) to 3). The number in bracket indicates the damage in percent calculated by the Colby formula from the individual effects of the active constituents. 1) On Stellaria media damage in 1> mg AS/pot compound B (mg AS/pot) 0 15 30 80 0 0 30 65 80 com- 7.5 0 (30) 40 (65) 75 (80) 90 pound 15 0 (30) 60 (65) 80 (80) 95 A 30 0 (30) 80 (65) 95 (80) 100 2) On Chenopodium album mg AS/pot damage in ί compound B (mg AS/pot) 0 15 30 0 0 30 75 com- 7.5 20 (40) 55 (80) 85 pound 15 40 (58) 75 (85) 95 A 30 60 (72) 85 (90) 99 8 9 18 - 12 3) On Galium iparinfdamage in % mg AS/pot compound B (mg AS/pot) 0 125 250 500 0 0 0 0 20 com- 62.0 40 (40) 45 (40) 60 (52) 65 pound 125 60 (60) 70 (60) 75 (68) 80 A 250 85 (85) 90 (85) 95 (88) 99

Claims (4)

1. Herbicidal composition containing as active ingredient a combination of a compound of the formula A (A) with a compound of the formula B {i)II 7 C 3 -NH-CO-N Z C,I 3 (B) CII.

2. Herbicidal composition as claimed ir. claim 1, wherein the mixing proportion of compound A to compound B is in the range of from 10:1 to 1:10. 10

3. · Herbicidal composition as claimed in claim 1, wherein the mixing proportion of compound A to compound B is in the range of from 4:1 to 1:4.

4. Method of using a composition as claimed in claims 1 to 3 for combating noxious plants in crop cultivations, 25 especially in cereals, which comprises applying said composition to a locus of said cultivations.