FR2753603A1 - Herbicide mixture for post-emergence treatment of maize - Google Patents

Abstract

Herbicidal compositions contain effective quantities of (a) a triazine; (b) 2-chloro-6-nitro-3-phenoxy aniline (I); and (c) one or more 3,5-dihalo-4-hydroxy benzonitrile herbicides, and optionally agronomically-acceptable adjuvants and/or supports.

Description

Herbicide combination based on triazine and other usable herbicides
for the weeding of maize
The present invention relates to a herbicidal product based on a mixture of triazines and other herbicidal active ingredients.

 Weed control is a particularly important problem because corn is a major crop in many countries.

 Triazines are up to now widely used for this weeding, but we know that these products pose various problems especially in relation to pollution, and more particularly the pollution of groundwater. It is therefore desirable to be able to reduce the dose of triazine used in the weeding of maize.

 Many herbicides or herbicide mixtures have already been proposed for weed control of maize. These products have had various successes. Some are good under certain conditions, other products are better in other conditions.

 It is always desirable to improve the action of herbicidal materials as well as their effectiveness, selectivity and persistence of action.

 A first object of the invention is to reduce the dose of triazine in the weeding of corn.

 Another object of the invention is to allow control (or destruction) of dicotyledonous weeds for a long period of time, for example at least one month, by means of a single herbicide treatment.

 Another object of the invention is to allow control (or destruction) of all broadleaf-type weeds infesting corn.

 Another object of the invention is to allow a control (or destruction) greater than 90%, preferably greater than 95%.

Another object of the invention is to allow control (or destruction) of all dicotyledonous weeds infesting corn, including Amaranthus retroflexus, Capsella bursa pastoris, Chenopodium album, Mercurialis annua, Polygonum aviculare, Polygonum convolvulus,
Polygonum persicaria, Senecio vulgaris, Solanum nigrum, Stellaria media.

 Another object of the invention is to allow weeding economic corn, that is to say having a low cost, while having a long-lasting effectiveness.

 It has now been found that these objects can be achieved in whole or in part by the compositions according to the invention and the weeding method according to the invention.

The invention therefore relates to a herbicidal composition comprising
a) an effective amount of triazine, and
b) an effective amount of 2-chloro-6-nitro-3-phenoxyaniline and,
c) an effective amount of one or more 3,5-dihalogeno-4-hydroxy benzonitrile herbicides (sometimes referred to as HBN),
and optionally adjuvants and / or agronomically acceptable formulation supports.

 The herbicides of the 3,5-dihalogeno-4-hydroxy benzonitrile type, according to the invention, can exist in the phenolic form of amine, potassium or sodium salts, or in the form of an ester, in particular with an alkanoic acid (from preferably an alkanoic acid comprising 4 to 8 carbon atoms).

 Among these herbicides, it is preferred to use bromoxynil or 3,5-dibromohydroxy benzonitrile in its ester or phenol form.

 For bromoxynil, the most commonly used forms are the ester forms for cereals and maize and the phenolic form for maize (at least in some countries, notably Europe). In general, the phenolic form is used at substantially higher doses than the ester form (1.8 to 2 times in general) but reveals a lower phytotoxicity, which justifies its use under certain conditions.

 For triazine, terbuthylazine or atrazine, preferably atrazine, is usually used.

 Preferably, the form used is the ester of bromoxynil or ioxynil with an alkanoic acid comprising from 4 to 8 carbon atoms.

 Advantageously, bromoxynil butyrate, heptanoate or octanoate or a mixture of two or three of these compounds will be used.

 These products can be used as herbicides in a very broad weight ratio range.

 The ratio or weight ratio c / b is generally between 1.5 and 4, preferably between 2 and 3.

The ratio or weight ratio c / a is generally between 0.05 and 0.5
preferably between 0.08 and 0.2.

The practical quantities of composition according to the invention used are such that the applied dose of active ingredient is generally understood.
between 500 and 1500 g / ha, preferably between 500 and 900 g / ha, for
the active ingredient a),
between 15 and 100 g / ha, preferably between 20 and 60 g / ha, for the
active ingredient b),
between 50 and 250 g / ha, preferably between 60 and 120 g / ha, for the
active ingredient c).

 The compositions according to the invention are preferably used post-emergence from the crop, in particular corn, and post-emergence weeds.

 These products according to the invention are intended for simultaneous, separate or spread over time for the herbicidal treatment of undesirable plants, especially against the weeds present in the crops.

Simultaneous application of the various constituents of the compositions according to the invention, which are thus and then used in a mixture, is preferred.

 In the case of simultaneous use, it is possible to use ready-to-use products containing the combination of the active ingredients described above. It is also possible to use products prepared just before use, by extemporaneous mixing of the active ingredients as described below.

 The use of the products according to the invention takes place most of the time in the form of a herbicidal composition comprising one or more agriculturally acceptable carriers and one or more surfactants, in addition to the herbicidal product. In particular, the usual inert carriers and surfactants are usable.

 These compositions usually contain between 0.5 and 95% of active ingredient or combination according to the invention. Percentages unless otherwise stated in percentages by weight.

 By the term "carrier" in this specification is meant an organic or inorganic material, natural or synthetic, with which the active ingredient or combination is combined to facilitate its application on the plant, on seeds or on the soil . This support is therefore generally inert and must be acceptable in agriculture, especially on the treated plant. The support may be solid (clays, natural or synthetic silicates, silica, resins, waxes, solid fertilizers, etc.) or liquid (water, alcohols, ketones, petroleum fractions, aromatic or paraffinic hydrocarbons, chlorinated hydrocarbons, liquefied gases , etc ...).

 The surfactant may be an emulsifier, dispersant or wetting agent of ionic type. There may be mentioned, for example, salts of polyacrylic acids, salts of lignosulfonic acids, salts of phenolsulphonic or naphthalenesulphonic acids, polycondensates of ethylene oxide with fatty alcohols or with fatty acids or with fatty amines. substituted phenols (especially alkylphenols or arylphenols), salts of sulfosuccinic acid esters, taurine derivatives (especially alkyltaurates), phosphoric esters of polyoxyethylated alcohols or phenols. The presence of at least one surfactant is very advantageous when the application carrier agent is water, since the associated active ingredients (2-chloro-6-nitro-3-phenoxy + HBN) are not soluble in water. 'water.

 As forms of agricultural compositions, mention may be made of powders for dusting or dispersion (with an active substance content of up to 100%) and granules, in particular those obtained by extrusion, by compacting, by impregnation of a granulated support, by granulation from a powder (the content of active materials in these granules being between 1 and 80% for the latter cases).

 As forms of compositions that are liquid or intended to constitute liquid compositions during application, mention may be made of emulsifiable concentrates, emulsions, concentrated suspensions, wettable powders (or powder for spraying) and pastes.

To illustrate these remarks, are given below some more precise information on this type of formulation:
the emulsifiable concentrates most often comprise 10 to 80% of active or combination material, 0.5 to 15% surfactants, 0.1 to 10% thickeners and 0 to 10% appropriate additives;
wettable powders (or spray powder) are usually prepared to contain from 20 to 95% active material, and usually contain, in addition to the solid support, from 0 to 5% of a wetting agent, 3 to 10% of a dispersing agent and, when necessary, 0 to 10% of one or more suitable additives.

 The suspoemulsions most often comprise 10 to 50% by weight of active ingredients or of combinations, from 0.5 to 15% of surfactants, from 0.1 to 10% of thickening agents and from 0 to 10% appropriate additives.

 The concentrated suspensions generally contain from 10 to 75% of active ingredients or combinations, from 0.5 to 15% surfactants, from 0.1 to 10% thickening agents and from 0 to 10% by weight. appropriate additives.

 Among these suitable additives, mention may be made of thixotropic colloids, penetration agents, stabilizers, sequestering agents, etc.

 Said compositions may also contain other active ingredients with pesticidal properties (in particular insecticides or fungicides), or with properties promoting the growth of plants (in particular fertilizers), or with growth-regulating properties provided that there is no major incompatibility between all these active ingredients.

 In the case of HBN s in ester form, it is preferable, subject to optimization within the reach of those skilled in the art of the formulation of plant protection products, to manufacture a suspoemulsion from a concentrate HBN emulsifiable ester form and 2-chloro 6-nitro 3phenoxy as a concentrated suspension.

 It is known that in this type of formulation, 2-chloro-6-nitro-3-phenoxy will be in the form of fine particles in suspension and the IIBN ester in the solubilized form, all in the form of a stable emulsion. .

 In the case of HBNs in phenolic form, it is preferable to manufacture a concentrated suspension while obviously always emitting the same reservations as to the industrial feasibility which will possibly require adjustments. In particular, care should be taken to avoid the formation of a eutectic between the two active ingredients.

 In the case of HBNs in salt form, it is possible to manufacture a concentrated suspension in which the HBN salt will be in dissolved form and 2chloro-6-nitro-3-phenoxyaniline in suspension.

 The invention also relates to a method for controlling weeds, especially those which grow, or are expected to grow, in a cereal crop, preferably maize, by applying an effective dose of composition containing the product according to the invention, as just described above.

 The invention also relates to a method as described above and allowing protection of the culture for a period equal to or greater than one month.

 When applied, the dose should be sufficient to control weed growth without causing permanent substantial damage to the crop. In this context, an effective dose is understood to mean the dose which makes it possible to obtain this result.

 The application is carried out post-emergence cultures. By post-emergence is meant the application of the product after emergence of the soil of the cultivated plant.

The mixture is active on the leaves of weeds, but also by application to the soil and subsequent root absorption.

 The product according to the invention is mainly active against weeds after they have raised although a pre-emergence action, that is to say while the plant has not yet emerged from the soil, is also possible.

 The action of the product is foliar and root in proportions that may vary depending on the active ingredients considered and the treated plants.

 The invention will now be described with respect to concrete examples of embodiments which are of course only indicative and can not in any way limit the scope of said invention.

Example
A composition according to the invention is applied to a corn culture in the 2 to 4 leaf stage. The application is made by foliar sprays of a slurry diluted in water obtained from a composition comprising 750 g / ha of atrazine, 75 g / ha of bromoxynil in phenol form, and 30 g / ha of 2-chloro-6-nitro-3-phenoxyaniline

After one month the following results are observed:

<tb><SEP> Poor <SEP> herb <SEP><SEP><SEP><SEP><SEP><SEP><SEP> Degree
<tb><SEP> report <SEP> to the <SEP> control <SEP> no <SEP> processed <SEP> = <SEP> rate <SEP> of
<tb><SEP> destruction <SEP> of <SEP> bad <SEP> grasses
<tb> Amaranthus <SEP> retroflexus <SEP> 95
<tb><SEP> Capsule <SEP> bursa <SEP> pasta <SEP><SEP> @ <SEP> 100
<tb><SEP> Chenopodium <SEP> album <SEP> 98
<tb><SEP> Mercurialis <SEP> annua <SEP> 99
<tb><SEP> Polygonum <SEP> aviculare <SEP> 100
<tb> Polygonum <SEP> convolvulus, <SEP> 100
<tb><SEP> Polygonum <SEP> persicaria <SEP> 98
<tb><SEP> Senecio <SEP> vulgaris <SEP> 100
<tb><SEP> Solanum <SEP> nigrum <SEP> 94
<tb><SEP> Stellaria <SEP> media <SEP> 100
<tb><SEP> Corn <SEP> (selectivity) <SEP>(SEP>SEP> damage <SEP> to <SEP><SEP> culture) <SEP> of <SEP> 0 <SEP> at <SEP> 5 <SEP>%,
<tb><SEP> in <SEP> average <SEP> 1.4%
<Tb>

Claims (12)

 1. Herbicide composition comprising  a) an effective amount of triazine, and  b) an effective amount of 2-chloro-6-nitro-3-phenoxyaniline and,  c) an effective amount of one or more 3,5-dihalogeno-4-hydroxy benzonitrile herbicides,  and optionally adjuvants and / or agronomically acceptable formulation supports.  2. Composition according to claim 1 comprising 0.5 to 95% active ingredient.  3. Composition according to one of the preceding claims wherein the herbicide type 3,5-dihalogéno-4-hydroxy benzonitrile is in phenol or ester form.  4. Composition according to one of the preceding claims wherein the compound c) is bromoxynil, and / or the compound a) is terbuthylazine or atrazine, preferably atrazine.  5. Composition according to one of the preceding claims wherein the ratio or weight ratio c / b is between 1.5 and 4, preferably between 2 and 3.  6. Composition according to one of the preceding claims wherein the ratio or weight ratio c / a is between 0.05 and 0.5, preferably between 0.08 and 0.2.  A method of weeding crops, preferably maize crops, in which an effective amount of a composition according to the preceding claims is applied.  8. The method of claim 7 for protection against weeds for a period of at least one month.  9. Method according to one of the preceding claims for a protection against weeds greater than or equal to 90%  10. Method according to one of the preceding claims for protection against dicotyledonous weeds in post-emergence of the crop.  11. Method according to one of the preceding claims for protection against weeds Amaranthus retroflexus, Capsella bursa pastoris, Chenopodium album, Mercurialis annua, Polygonum aviculare, Polygonum convolvulus, Polygonum persicaria, Senecio vulgaris, Solanum nigrum, Stellaria media.  12. Method according to one of the preceding claims wherein the application of the active ingredients is made at a dose of between 500 and 1500 g / ha, preferably between 500 and 900 g / ha, for the active ingredient a ), between 15 and 100 g / ha, preferably between 20 and 60 g / ha, for the active ingredient b),  between 50 and 250 g / ha, preferably between 60 and 120 g / ha, for the active ingredient c).