FR2625410A1 - Synergistic herbicidal combination based on bifenox and isoxaben - Google Patents

Abstract

Synergistic herbicidal combination which can be used especially in the pre-emergence treatment of weeds in cereal crops consisting a of isoxaben and b of bifenox, preferably in a weight ratio a:b of between 0.02 and 2.

Description

 The subject of the present invention is a synergistic association consisting in the combination of isoxaben, optionally in the form of salts, and bifenox, the use of this association as a herbicide, in particular in the form of herbicidal compositions, a process for controlling or pre-emergence weed control, particularly applicable to grain fields.

 Isoxaben is described in the "Pesticide Manual, 8th edition and in EP-A-0049071 (Eli Lilly).

 Bifenox is described in the "Pesticide Manual, 8th edition" and in US 3,652,645.

 These two herbicides are known for weeding pre-emergence cereals.

In an anonymous publication CA 107 (19): 170488 k, it is also mentioned the mixture of isoxaben and bifox (187.5 g of bifenox and 462.5 g of dimethylawmonium salt of Mecoprop) useful as a post-emergence herbicide for cereal weeds like
Veronica hederifolia and Pioris echioides.

We also knew well from the patent
US 4,636,243 (col. 69, 1.68) the mention among many compounds of the possibility of the bifenox-isoxaben association but this is a generic disclosure which does not describe the surprising herbicidal effect obtained with said association of the invention, as will be described below.

 Surprisingly, in fact, it has been found that the abovementioned combination makes it possible on the one hand to broaden the spectrum of activity of the two herbicides taken in isolation and on the other hand reveals a herbicidal effect much higher than that which would have been expected.

This is particularly the case for the following weeds grasses Lolium multiflorum or dicotyledon ryegrass Sinapis alba or mustard
Stellaria media or stellar
Galium aparine or bedstraw
Thus, the combination of isoxaben and bifenox presents a remarkable degree of synergism as defined by PML Tammes, Netherlands Journal of Plant
Pathology, 70 (1964), p. 7380 in an article entitled "Isoboles, a graphic representation of synergy in pesticides" or as defined by Limpel, LE, PH

Schuldt and D. Lamont, 1962, Proc. NEWCC 16: 48-53, using the formula E = X + Y--
100
where E is the expected percentage inhibition of
growth by mixing the two herbicides with
defined doses,
X is the percentage of inhibition observed of the
growth with herbicide A at a defined dose,
Y is the observed percentage of inhibition of
growth with herbicide B at a defined rate.

 When the observed inhibition percentage of the association is greater than E there is synergy.

This synergy makes it possible to considerably reduce the dose normally required, which induces several advantages.
- less residual products in the soil,
- decrease in colts,
- etc ..

Preferably, a combination will be used in which the isoxaben: bifenox weight ratio is between 0.02 and 2
Even more preferably, the isosaben-bifenox weight ratio is between 0.03 and 0.6
For their practical use, the associations according to the invention are rarely used alone. Most often these associations are part of compositions. These compositions, which can be used as herbicide agents, contain as active material a combination according to the invention as described above in admixture with solid or liquid carriers, acceptable in agriculture and surfactants also acceptable in agriculture. inert and usual supports and the usual surfactants. These compositions are also part of the invention.

 These compositions can also contain all kinds of other ingredients such as, for example, protective colloids, adhesives, thickeners, thixotropic agents, penetrating agents, stabilizers, sequestering agents, etc. More generally, the combinations used in the invention can be combined with all the solid or liquid additives corresponding to the usual techniques of formulation.

The doses of use of the associations used in the invention can vary within wide limits, in particular according to the nature of the weeds to be eliminated.
and the usual degree of crop infestation for these weeds.

 In general, the compositions according to the invention usually contain from 0.05 to 95 x approximately (by weight) of a combination according to the invention, one or more solid or liquid supports and, optionally, one or more agents surfactants.

 By the term "support", in the present description, we mean an organic or mineral, natural or synthetic material, with which the association is combined to facilitate its application on the plant, on seeds or on eol. This support is therefore generally inert and it must be acceptable in agriculture, in particular on the treated plant. The support can be solid (clays, natural or synthetic silicates, silica, resins, waxes, solid fertilizers, etc.) or liquid (water alcohols, in particular butanol, etc.).

 The surfactant can be an emulsifying, dispersing or wetting agent of ionic or nonionic type or a mixture of such surfactants. Mention may be made, for example, of salts of polyacrylic acids, salts of lignosulfonic acids, salts of phenolsulfonic or naphthalene sulfonic acids, polycondensates of ethylene oxide on fatty alcohols or on fatty acids or on fatty amines , substituted phenols (in particular alkylphenols or arylphenols), ester salts of sulfosuccinic acids, taurine derivatives (in particular alkyltaurates), phosphoric esters of alcohols or po.tyoxyethylated phenols, esters of fatty acids and polyols, sulfate, sulfonate and phosphate derivatives of the above compounds.

The presence of at least one surfactant is generally essential when at least one of the two compounds of the combination and / or the inert support are not soluble in water and the vector agent for the application is the water.

 For their application, the associations are therefore generally in the form of compositions. These compositions according to the invention are themselves in fairly diverse forms, solid or liquid.

 As forms of solid compositions, mention may be made of powders for dusting (with an association content of up to 100%) and granules, in particular those obtained by extrusion, by compacting, by impregnation of a granulated support, by starting from a powder (the association content in these granules being between 0.5 and 80% for these latter cases).

 As forms of liquid compositions or intended to constitute liquid compositions during application, mention may be made of solutions, in particular concentrated suspensions, wettable powders (or spraying powder), butodispersible granules and pastes.

 The concentrated suspensions, which are applicable in spraying, are prepared so as to obtain a stable fluid product which does not deposit (fine grinding) and they usually contain from 10 to 75 Z of association, from 0.5 to 15 Z of surfactants, 0.1 to 10% thixotropic agents, 0 to 10% suitable additives, such as defoamers, corrosion inhibitors, stabilizers, penetrating agents and adhesives and, as a carrier , water or an organic liquid in which the active ingredient is sparingly soluble or insoluble certain organic solids or mineral salts may be dissolved in the carrier to help prevent sedimentation or as antifreeze for water.

As an example, here is a concentrated suspension composition
Example: - combination 500 g - polyethoxylated tristyrylphenol phosphate 50 g - polyethoxylated alkylphenol 50 g - sodium polycarboxylate 20 g - ethylene glycol 50 g - organopolysiloxane oil (defoamer) 1 g - polysaccharide 1.5 g - water 316.5 g
Wettable powders (or spray powder) are usually prepared so that they contain 20 to 95% of association, and they usually contain, in addition to the solid support, 0 to 5% of a wetting agent, 3 to 10% of a dispersing agent, and, when necessary, from 0 to 10% of one or more stabilizers and / or other additives, such as penetrating agents, adhesives, or anti-caking agents, coloring agents, etc.

As an example, here are various compositions of wettable powders
Example - combination 50 Z - calcium lignosulfonate (deflocculant) 5 Z - isopropylnaphthalene sulfone te (agent
anionic wetting agent) 1 Z - anti-clumping silica 5 X - kaolin (filler) 39 Z Example - association 80 Z - sodium alkylnaphthalene sulfonate 2 Z - sodium lignosulfonate 2 Z - anti-clumping silica 3% - kaolin 13 Z Example - association 50 Z - sodium alkylnaphthalene sulfonate 2 X - low viscosity methyl cellulose 2 Z - diatomaceous earth 46 Z
Example - combination 90 Z - sodium dioctylsulfosuccinate 0.2 Z - synthetic silica 9.8 Z
Example - combination 400 g - sodium lignosulfonate 50 g - sodium dibutylnaphthalene sulfonate 10 g - silica 540 g Example - combination 250 g - isooctylphenoxy-polyosyethylene-ethanol 25 g - equiponderal mixture of chalk
Champagne and hydroxyethylcellulose 17 g - sodium aluminosilicate 543 g - kieselguhr 165 g Example - combination 100 g - mixture of sodium salts of sulfates
saturated fatty acids 30 g - condensation product of naphthalene acid
sulfonic and formaldehyde 50 g - kaolin 820 g
To obtain these sprayable powders or wettable powders, the active materials are intimately mixed in appropriate mixers with the additional substances or one or the other or both of the compounds of the combination are impregnated on the porous filler and ground with mills or other suitable grinders. Powders to be sprayed are obtained, the wettability and suspension of which are advantageous; they can be suspended with water at any desired concentration.

 The “self-dispersible” granules (in English “dry flowable”; more precisely, they are granules easily dispersible in water) have a composition substantially similar to that of wettable powders. They can be prepared by granulation of formulations described for wettable powders, either by the wet route omitted in contact with the finely divided association with the inert filler and with a little water, for example 1 to 20 ×, or of aqueous solution of dispersant or binder, then drying and sieving), or by dry process (compacting then grinding and sieving).

As an example, here is a self-dispersible granule formulation Example - combination 800 g - sodium alkylnaphthalene sulfonate 20 g - methylene bis naphthalene sulfonate
sodium 80 g - kaolin 100 g
Instead of wettable powders, legs can be made. The conditions and methods of making and using these pastes are similar to those of wettable powders or spraying powders.

 As has already been said, aqueous dispersions and emulsions, for example compositions obtained by diluting a wettable powder according to the invention with water, are included in the general scope of the compositions which can be used in the present invention.

 All these aqueous or boiled dispersions or emulsions are applicable to crops to be weeded by any suitable means, mainly by spraying, at doses which are generally of the order of 50 to 500 liters of porridge per hectare.

 The granules intended to be placed on the ground are usually prepared so that they have dimensions of between 0.1 and 2 μm and they can be produced by agglomeration or impregnation. Preferably, the granules contain 1 to 95% of association and 0 to 50% of additives such as stabilizers, slow release modifiers, binders and solvents.

According to an example of granule composition, the following constituents are used Example - association 50 g - propylene glycol 25 g - boiled linseed oil 50 g - clay (particle size: 0.3 A o, 8 mm) 910 g
The combinations, optionally in the form of compositions described above, are intended for herbicide treatment preemergence of weeds. The above use provides residual activity.

 It is advantageous to use ready-to-use products containing the combination of active ingredients, optionally in the form of compositions. It is also possible to use products prepared just before use, by extemporaneous mixing of the active ingredients or compositions containing each of the active ingredients.

 The expression "pre-emergent application" is intended to denote application to the soil in which the seeds or seedlings of the weeds are present, before the emergence of the weeds above the surface of the soil.

The term "residual activity" is used to denote the herbicidal activity produced by application to the soil in which the seeds or seedlings of the weeds are present, before the emergence of the weeds above the surface of the soil, making it possible to combat seedlings present at the time of application or which germinate, after application, from seeds present in the soil.

Weeds which can be controlled by the method include among the dicotyledonous weeds: Galium aparine,
Sinapis arvensis, Sinapis alba, Stellaria media and among the grasses: Lolium multiflorum.

 Thus, the invention also relates to a process for combating weeds in pre-emergence, particularly in a place of cultivation of cereals such as wheat, barley, oats, rye, characterized in that an effective dose of an association or a composition as defined above is applied to them. The combinations or compositions described above will preferably be applied at a rate of 20 to 200 g / ha of isoxaben, optionally in the form of salts, and 100 to 1000 g / ha of bifenox and preferably at a rate of 30 to 150 g / ha d 'isoxaben, possibly in the form of salts, and 250 to 750g / ha of bifenox.

Example 1
Test showing the nature of the biological synergistic effect of the isoxaben-bifenox combination on Sinapis alba (white mustard)
Sinapis alba seeds are sown in 7 x 7 x 8 cm pots filled with light agricultural soil. The seeds are then covered with a layer of soil about 3 mm thick.

The pots are treated by spraying with an amount corresponding to an application dose, by volume, of 500 l / hua, containing the combination at the desired concentration. The spray mixture is prepared by mixing
- some water,
- a concentrated suspension with 480 g / l of bifenox (MODOWN 4 F)
- a concentrated suspension with 125 g / l of isoxaben (CENT 7).

 The treatment with the porridge is therefore carried out on seeds covered with soil (the term porridge is used to designate, in general, the compositions diluted with water, such as they are applied to plants or to the soil).

 Different concentrations of the active ingredients of the spray liquid are used, corresponding to different doses of the active ingredients applied.

 The treated pots are then placed in tubs intended to receive irrigation water by subirrigation, and they are kept at room temperature for 24 days at a relative humidity of 70 X.

 24 days after the treatment, the number of living plants is counted in the pots treated with the spraying liquid containing the association to be tested, and the number of living plants is also counted in a control pot treated according to the same conditions but using a spray liquid that does not contain active ingredients. The percentage equal to 100 Z indicates that there is a total destruction of the plant species considered, and a percentage equal to O Z indicates that the number of living plants in the treated pot is identical to that in the control pot.

bifenox
125g 250g 500g Sinapis
0 0 0 alba
62g 80 95 100 100
125g 80 98 98 95
isoxaben
Example 2
Test showing the nature of the biological synergistic effect of the isoxaben-bifenox association on Lolium multiflorum
The experiment is carried out according to that described in Example 1, having sown seeds of Lolium multiflorum (ryegrass).

The results indicated in the table below clearly show, with reference to the formula indicated at the beginning of the description, the excellent and unexpected degree of synergy obtained with the combination of the invention.
bifenox
125g 250g 500g Lolium
OOO multiflorum
125g 0 0 20 20
250g 0 20 50 50
isoxaben
Example 3
Trial showing the nature of the biological synergistic effect of the isoxaben-bifenox association on Stellaria media
The experiment is carried out according to that described in Example 1 having sown seeds of Stellaria media (stellar).

The results indicated in the table below clearly show, with reference to the formula indicated at the start of the description, the excellent and unexpected degree of synergy obtained with the combination of the invention.
bifenox
250g 500g lOOOg Stellaria
0 0 0 media
31g 80 90 20 98
62g 80 100 98 98
125g 90 100 100 100
isoxaben
Example 4
Test showing the nature of the biological synergistic effect of the isoxaben-bifenox association on Galium aparine
The experiment is carried out according to that described in Example 1 having sown seeds of 'Galium aparine (bedstraw).

The results indicated in the table below clearly show, with reference to the formula indicated at the beginning of the description, the excellent and unexpected degree of synergy obtained with the combination of the invention
bifenox
250g 500g lOCOg Galium
0 20 30 aparine
31g 0 0 40 80
62g 0 0 20 95
125g 20 10 10 95
isoxaben

Claims (6)

 between 0.02 and 2, preferably between 0.03 and 0.6.  characterized in that the weight ratio a: b is  salts (b), and bifenox 2) herbicide association according to claim 1),  combination (a) of isoxaben, possibly in the form  CLAIMS 1) Synergistic herbicide association resulting from the 3) Herbicidal composition comprising 0.05 to 95% by weight  of an association according to one of claims 1 or 2  in combination with an inert support acceptable in  Agriculture. 4) herbicidal composition according to claim 3,  characterized in that it is in the form of a  concentrated suspension, wettable powder or  granules. 5) Pre-emergence weed control process,  especially in cereal crops, characterized by  what we apply an association according to one of  claims 1 or 2 or a composition according to one of  claims 3 or 4 at 20 to 200g / ha  isoxaben, possibly in the form of salts, and 100 to  1000ha of bifenox and preferably 30 a  150g / ha of isoxaben, possibly in the form of salts,  and 250 to 750 g / ha of bifenox. 6) control method according to claim 5,  characterized in that the weeds are chosen  among:  Sinapis Alba  Lolium multiflorum  Stellaria media  Galium aparine.