FUMIGANT FORMULATION FOR DROP APPLICATION

The present invention relates to the field of the fumigation of soils and/or substrates, and more particularly to a fumigant formulation suitable for drip administration, as well as its use. The present invention also relates to a method of pesticide treatment by fumigation of soils and/or substrates using such a formulation, administered drop by drop.

Fumigants are well-known chemical substances that inhibit or kill plant destructive and/or harmful organisms such as nematodes, fungi, insects, weeds and others. Fumigants most often come in the form of volatile liquids, solids or gases. Fumigants have the property of diffusing into the soil and/or the substrate to be treated in the form of a gas once administered.

The soil fumigation technique is now used in many situations (agriculture, arboriculture, horticulture, market gardening) and for a wide range of crops. More particularly, fumigation is used for the crops of plants with high added value such as, for example, crops of tomatoes, strawberries, melons, cucumbers, peppers, but also potatoes, carrots, vines, fruit trees and cut flowers, not to mention mention only the main ones.

To ensure maximum effectiveness, fumigants are most often deposited on the ground or introduced into the ground by injection. Currently, two techniques are commonly used to administer fumigants, namely:

- using coulters, allowing injection into the soil at depths varying from a few centimeters to a few tens of centimeters; and

- drop by drop (“drip” in English), with a system placed on the ground or buried. The main advantages of fumigation by drip are the ease of implementation, the flexibility of use and the lower toxicity given that the administration vector (the solvent) of the fumigant is water.

Among the known fumigants, dimethyl disulphide (also called DMDS) is described in application WO 02/074083 as a broad-spectrum fumigant with nematicide, fungicide, insecticide and bactericide properties. It can be used alone or in co-application with other fumigants.

However, the fumigants used, and in particular DMDS, are sometimes poorly soluble in water. Drip administration can then pose problems of fumigant dosage on the plot to be treated. Due to its low solubility, the fumigant is not evenly distributed and may accumulate in some areas while other areas will not.

sufficiently processed. Thus, depending on the humidity of the ground, the atmospheric conditions, the additional watering conditions which can be carried out, fumigants, including DMDS, can accumulate more or less in certain regions of the soil or substrate, causing for crops there is a local risk of over-dosing or, conversely, of under-dosing.

In addition, the fumigant can clog the drippers and alter the dripper lines if used alone, which poses problems both in terms of the effectiveness of the fumigation and the equipment used. Indeed, some fumigants, in particular DMDS, are not compatible with most plastic materials.

There is therefore a need for a fumigant formulation which allows effective pesticide treatment, by ensuring homogeneous distribution over the soil and/or the substrate to be treated of the fumigant used.

There also exists a need for a stable fumigant formulation, which allows sufficient solubilization, and which is suitable for dropwise administration.

One of the objectives of the present invention is therefore to provide a fumigant formulation suitable for dropwise administration.

Another objective of the present invention is to provide a stable fumigant formulation, in particular in the form of an emulsion.

Another objective of the present invention is to provide an effective method of pesticide treatment by fumigation by drip and allowing a homogeneous distribution of the fumigant on the ground and/or the substrate to be treated, with an improved implementation.

Thus, the present invention relates to a formulation F comprising water and between 0.10% and 0.40% by volume of a composition C, relative to the total volume of water of the formulation F, said composition C comprising :

- at least 80% by weight, preferably at least 90% by weight, of at least one fumigant compound relative to the total weight of composition C;

- between 0.1% and 20%, preferably between 1% and 10%, by weight of at least one surfactant relative to the total weight of composition C; and

- optionally an odor masking agent, for example between 0.1% and 0.5% by weight of an odor masking agent relative to the total weight of composition C.

Formulation F according to the invention is preferably an emulsion, more preferably a micro-emulsion. For example, the particles of the emulsion have a size less than or equal to 0.1 μm.

Said formulation F may in particular comprise between 0.10% and 0.30%, preferably between 0.15% and 0.25% by volume of said composition C, relative to the total volume of water of formulation F. Said formulation F may comprise between 0.15% and 0.40% by volume of said composition C, relative to the total volume of water of formulation F.

The present invention thus relates to a formulation F comprising water and a composition C, said composition C comprising:

- at least 80% by weight, preferably at least 90% by weight, of at least one fumigant compound relative to the total weight of composition C;

- between 0.1% and 20% by weight, preferably between 1% and 10% by weight, of at least one surfactant relative to the total weight of composition C; and

- optionally an odor masking agent;

formulation F being characterized in that the volume ratio [composition C]/[water] is between 0.10/100 and 0.40/100 (i.e. between 0.0010 and 0.004), preferably between 0.10/ 100 and 0.30/100 (i.e. between 0.0010 and 0.003), and even more preferably between 0.15/100 and 0.25/100 (i.e. between 0.0015 and 0.0025).

In order to prepare such a formulation, it is possible in particular to use an emulsifiable fumigant concentrate. According to a particularly preferred embodiment, the emulsifiable concentrate corresponds to composition C as defined previously. It may quite preferably correspond to the dimethyl disulphide compositions marketed by Arkema under the names Paladin® EC, Accolade® EC and Atomal® 13. According to one embodiment, said composition C does not comprise water .

Composition C may in particular comprise at least one fumigant compound, preferably DMDS, in an amount at least strictly greater than 90% by weight, preferably between strictly greater than 90% and 95% by weight, relative to the total weight of composition C.

Preferably, composition C comprises:

- at least 90% by weight, for example between 90% and 95% by weight, of dimethyl disulphide relative to the total weight of composition C;

- between 1% and 10% by weight of at least one surfactant relative to the total weight of composition C; and

- optionally between 0.1% and 0.5% by weight of an odor masking agent relative to the total weight of composition C.

Composition C comprises in particular, or even consists of:

- at least 90% by weight of fumigant, for example dimethyl disulphide, relative to the total weight of composition C;

- between 1% and 10%, preferably between 1% and 6%, by weight of at least one (C 10 -C 13 )alkyl-benzene-sulfonate relative to the total weight of composition C; and

- optionally between 0.1% and 0.5% by weight of an odor masking agent relative to the total weight of composition C.

The formulations F and the compositions C as according to the invention can be prepared according to methods well known to those skilled in the art. For example, the following method can be used:

- preparation of composition C by simple mixing of its components, optionally with stirring and heating, the order of addition of the components not influencing composition C; then

- preparation of the formulation F by adding water to the composition C obtained, optionally with stirring.

Formulation F can also be in a ready-to-use form.

The present inventors have discovered that the best compromise between efficacy of the fumigant and homogeneity of distribution in the soil and/or substrate to be treated, when administration by drip is envisaged, is the use of a particular formulation allowing to obtain a stable emulsion.

By pesticide treatment is meant in particular a treatment having at least one action chosen from nematicide, fungicide, insecticide, herbicide and bactericide actions, in particular towards phytopathogenic organisms.

By substrates is meant in particular potting soil, peat, rock wool, or other supports commonly used for the cultivation of plants and in particular above-ground crops.

Fumigant compounds

Fumigant compounds are known and widely described in the literature. Fumigants must meet three conditions in particular in order to be used practically for disinfection of soils and/or substrates:

- they have global pesticidal properties (in particular at least one of nematicide, fungicide, herbicide, insecticide and bactericide);

- they are capable of rapidly diffusing into the thickness of the soil and/or of the substrate to be treated in the form of gas; and

- they lead to a gas concentration sufficient to kill the phytopathogenic organisms present.

As fumigants, mention may be made in particular of:

1,3-dichloropropene, sulfuryl fluoride (S0 2 F 2 ), phosphine, methyl iodide, chloropicrin (CI 3 C-NO 2 ), Metam-sodium (CH 3 -NHCS 2 Na) , sodium tetrathiocarbonate (Na 2 CS 4 ), MITC (CH 3 -NCS), Dazomet (MITC generator), AITC (Allyl Iso thio cyanate), EDN (ethanedinitrile) and the compounds of formula (1) below including DMDS.

International application WO 2002/074083 describes in particular fumigants based on sulfur compounds, and in particular the compounds corresponding to the following general formula (1)

RS(0) n -S x -R' (1)

in which R is chosen from an alkyl radical, linear or branched, containing from 1 to 4 carbon atoms, and an alkenyl radical, linear or branched, containing from 2 to 4 carbon atoms; n is equal to 0, 1 or 2; x is an integer chosen from 0, 1, 2, 3 or 4, preferably x represents 1, 2, 3 or 4; R' is chosen from an alkyl radical, linear or branched, containing from 1 to 4 carbon atoms, and an alkenyl radical, linear or branched, containing from 2 to 4 carbon atoms or, only when n = x = 0, a hydrogen or alkali metal atom.

As non-limiting examples of R and R′ radicals, mention may be made of the methyl, propyl, allyl and 1-propenyl radicals.

Preferably, n = 0, that is to say the compounds corresponding to the formula (1 '):

RSS x -R' (1')

in which R and R', identical or different, preferably identical, each independently represent a linear or branched alkyl or alkenyl radical, preferably alkyl, containing from 1 to 4 carbon atoms, and x represents 1 , 2, 3 or 4.

A very particularly preferred compound according to the invention is dimethyl disulphide (DMDS).

According to a variant of the present invention, two or more fumigants can be used, in a mixture or separately, alternately or in sequence. Thus, if two or more fumigants are applied, these can either:

- be present together in formulation F; Where

- be applied alternately or in sequence, at least one of the fumigants being in the form of formulation F. Thus, formulation F can be used according to the invention in combination or in addition with other fumigants.

In particular, two or more fumigants can be used as indicated above, for example having complementary or synergistic activities chosen from:

1,3-dichloropropene, sulfuryl fluoride (S0 2 F 2 ), phosphine, methyl iodide, chloropicrin (CI 3 C-NO 2 ), Metam-sodium (CH 3 -NHCS 2 Na) , sodium tetrathiocarbonate (Na 2 CS 4 ), MITC (CH 3 -NCS), Dazomet (MITC generator), AITC (Allyl Iso thio cyanate),

EDN (ethanedinitrile) and the compounds of formula (1), and in particular the dialkyl disulphides, for example DMDS.

More preferably, formulation F according to the invention comprises DMDS and at least one other fumigant chosen from the group consisting of:

1,3-dichloropropene, sulfuryl fluoride (S0 2 F 2 ), phosphine, methyl iodide, chloropicrin (CI 3 C-NO 2 ), Metam-sodium (CH 3 -NHCS 2 Na), sodium tetrathiocarbonate (Na 2 CS 4 ), MITC (CH 3 -NCS), Dazomet (MITC generator), AITC (Allyl Iso thio cyanate) and EDN (ethanedinitrile).

More preferably, DMDS can be combined with 1,3-dichloropropene, chloropicrin (CI 3 C-NO 2 ), Metam-sodium (CH 3 -NHCS 2 Na), AITC (Allyl Iso thio cyanate ) or EDN (ethanenitrile); for example DMDS can be associated with EDN. Preferably, DMDS can be combined with chloropicrin.

It would not be departing from the present invention to use conventional pesticides (ie non-fumigant pesticides), alternately or in a complementary manner with formulation F according to the invention.

The fumigants according to the invention, and in particular DMDS, can also be used alternately or in a complementary manner with new pesticides or biocides, for example as described in application PCT/US2019/016448.

In particular, sodium hypochlorate, hydrogen peroxide (H 2 O 2 ), or a peroxide source such as peracetic acid, sodium peroxide, potassium oxide, potassium peroxide can be used. , calcium peroxide, magnesium peroxide, urea peroxide, organic hydroperoxides (RaOOH), organic peroxides (RaOORa), and superoxides, in which Ra is an alkyl, an alkenyl or an alkynyl, linear or branched, comprising from 1 to 12 carbon atoms or is an aromatic ring preferably with 6 carbon atoms, or a combination of aromatic rings, or other compounds capable of producing reactive oxygen.

Such an alternating or additional treatment can be carried out pre- or post-application of formulation F as according to the invention, preferably in post-treatment.

In the context of the present invention, formulations F comprising DMDS as sole fumigant are very particularly preferred.

Surfactants

The formulations F according to the invention can be obtained by adding at least one surfactant(s) to the fumigant compound(s), then by adding to the mixture obtained a certain quantity of water so as to obtain an emulsion, preferably a microemulsion. In a completely

As preferred, the formulations F according to the invention are aqueous emulsions (having water as solvent).

Are more particularly suitable for the preparation of these emulsions or microemulsions surfactants with a predominantly hydrophilic nature, that is to say those having an HLB ("Hydrophilic Lipophilic Balance") greater than or equal to 8, which may be of anionic nature, cationic, nonionic or amphoteric.

As non-limiting examples of anionic surfactants, mention may be made of:

- alkali metal, alkaline-earth metal, ammonium or triethanolamine salts of alkyl-, aryl- or alkylaryl-sulphonic acids, fatty acids at basic pH, sulfosuccinic acid or alkyl, dialkyl, alkylaryl or polyoxyethylene-alkylaryl sulfosuccinic acid;

- the alkali or alkaline-earth metal salts of sulfuric, phosphoric, phosphonic or sulfoacetic acid esters and of saturated or unsaturated fatty alcohols, as well as their alkoxylated derivatives;

- Alkali or alkaline-earth metal salts of alkylarylsulphuric, alkylarylphosphoric, alkylarylsulfoacetic acids, as well as their alkoxylated derivatives.

The cationic surfactants that can be used are, for example, those of the family of quaternary alkylammoniums, sulfoniums or fatty amines at acid pH, as well as their alkoxylated derivatives. As non-limiting examples of nonionic surfactants, mention may be made of alkoxylated alkyl phenols, alkoxylated alcohols, alkoxylated fatty acids, glycerol fatty esters or fatty sugar derivatives.

The amphoteric surfactants that can be used are, for example, alkyl-betaines or alkyl-taurines.

The preferred surfactants for the preparation of formulations F according to the invention are compounds based on alkyl-benzene-sulphonate and/or on alkoxylated alkyl-phenol. More particularly, use is made of (C 10 -C 13 )alkyl-benzene-sulphonates (also called salts of C 10 -C 13 alkyl derivatives of benzene sulphonic acid), for example the calcium salts of C 10 -C 13 alkyl derivatives 10 -C 13 of benzene sulphonic acid (CAS number 1335202-81-7) and in particular their mixtures in any proportion. The said (C 10 -C 13) Alkyl-benzene-sulphonates may or may not be mixed with other surfactants, for example with nonionic surfactants, optionally in the presence of an organic solvent such as 2-ethylhexan-1-ol.

The surfactants used can be in the form of commercial compositions, for example Atlox™ 4851 B marketed by Croda, T-Mulz® TE-CP marketed by Harcros Chemicals.

Odor masking agent:

Some fumigants have a strong, unpleasant or even aggressive odor. In particular, DMDS has a strong and aggressive odor due partly to the presence of strong-smelling impurities and partly to the garlicky and ethereal odor intrinsic to this molecule. The same is true for most organic sulphides.

In general, the oxides of these organic sulphides, in particular DMSO, have a less aggressive odor. However, depending on the concentrations of impurities, this smell can be unpleasant and bothersome for the end user.

Thus, according to the present invention, formulation F may also comprise an odor masking agent. Any type of known odor masker can be used. By “odor masking agent”, is meant a compound or a composition comprising several compounds making it possible to reduce, eliminate or mask the odor of the fumigant used. Mention may be made, for example, of chloropicirin, generally used to odorize methyl bromide.

In particular, it is possible to use an odor masking agent as described in application WO 2011/012815 incorporated here by reference.

Said odor masking agent can comprise at least one mono-ester, at least one di- and/or tri-ester, at least one alcohol, at least one ketone and optionally at least one terpene. According to a preferred embodiment, the odor masking agent comprises:

a1) from 1% to 40% by weight of at least one mono-ester;

a2) from 10% to 70% by weight of at least one di- and/or tri-ester;

a3) from 1% to 30% by weight of at least one alcohol;

a4) from 0.5% to 20% by weight of at least one ketone of formula R a -CO-R b , in which R a represents a hydrocarbon chain comprising from 1 to 6 carbon atoms, linear or branched, optionally comprising one or more unsaturation(s) in the form of double bond(s), and R b represents a cyclic hydrocarbon chain or else a linear or branched hydrocarbon chain optionally but preferably substituted by a cyclic structure, R b comprising 6 to 12 carbon atoms, optionally comprising one or more unsaturation(s) in the form of double bond(s) and optionally being substituted by one or more hydroxyl groups; and

a5) optionally up to 20% by weight of at least one terpene.

The percentages of a1, a2, a3, a4 and a5 are percentages by weight expressed relative to the total weight of the odor masking agent.

Unless otherwise stated, "ppm" means parts per million by weight.

Said odor masking agent can therefore comprise from 1% to 40%, preferably from 2% to 35%, more preferably from 5% to 30% by weight, relative to the total weight of the odor masking agent , of at least one mono-ester mentioned under a1).

As illustrative, but non-limiting, examples of mono-esters mentioned under a1), mention may be made of saturated or unsaturated C2-C20 acid esters, such as acetates, propionates, butyrates, methylbutyrates, pentanoates, hexanoates, heptanoates, caproates, oleates, linoleates, linolenates, ethyl, propyl, butyl, pentyl, 2-methylbutyl, iso-amyl, hexyl, benzyl, phenylethyl, menthyl, carvyl, and others , as well as mixtures thereof.

Are more particularly preferred iso-amyl acetate, hexyl acetate, 2-methylbutyl butyrate, iso-amyl butyrate, benzyl acetate, phenylethyl acetate and mixtures of these compounds.

The odor masking agent may also comprise at least one di- and/or triester a2), in an amount of between 10% and 70% by weight, preferably between 15% and 65% by weight, preferably still between 20% and 60% by weight, based on the total weight of the odor masking agent. Mention may be made, without limitation, of at least one di- and/or tri-ester chosen from ortho-phthalates, such as diethyl ortho-phthalate; citrates, such as triethyl citrate; and malonates, such as diethyl malonate.

The odor masking agent may also comprise from 1% to 30%, preferably from 5% to 25% by weight relative to the total weight of the odor masking agent, of at least one alcohol a3), advantageously at least one mono-alcohol comprising from 1 to 30 carbon atoms, preferably from 6 to 20 carbon atoms, more preferably from 8 to 11 carbon atoms, said carbon atoms forming a linear or branched chain optionally comprising a or more unsaturation(s) in the form of double bond(s), and optionally comprising a 5- or 6-membered, saturated, or totally or partially unsaturated cyclic structure.

The alcohols defined above are preferably monoalcohols, the hydroxyl function preferably being carried by an sp2 carbon atom. It should be understood that the hydroxyl function can also be carried by a carbon atom included in a cyclic structure as defined above.

The alcohols used in the odor masking agent and as defined above are advantageously and by way of nonlimiting examples chosen from menthol, neo-menthol, phenylethyl alcohol, benzyl alcohol, citronellol , dihydromyrcenol, dihydroterpineol, dimetol, ethyl-linalool, geraniol, linalool, tetrahydrolinalool, tetrahydromyrcenol, nerol, and others, as well as mixtures of two or more thereof.

The ketone or ketones indicated under a4) above are chosen, by way of nonlimiting examples, and preferably, from damascones, damascenones, ionones,

irisones, methylionones, frambinone (CAS#5471-51-2), and others, as well as mixtures thereof. The amount of ketone(s) is advantageously between 0.5% and 20%, preferably between 1% and 10% by weight relative to the total weight of the odor masking agent. The odor masking agent may optionally also comprise up to 20%, preferably from 1% to 10% by weight relative to the total weight of the odor masking agent, of at least one terpene.

As examples of terpenes, indicated under a5), which can be used, mention may be made, without limitation, of terpinenes, myrcene, limonene, terpinolene, pinenes, sabinene, camphene, and others, mixtures of two or more of them, as well as essences based on terpenes, in particular those comprising these ingredients.

In addition, the odor masking agent that can be used in the context of the present invention may comprise, in minor quantities, other agents (fragrances) usually used in the field of perfumery, and in particular one or more compounds carrying cyclic aldehyde and/or ketone function(s), among which mention may be made, without limitation, of geranial, neral, citronellal, menthone, iso-menthone, 1,8-cineole, ascaridole , flavonone, and mixtures thereof.

The odor masking agent can, where appropriate, see if necessary, also comprise one or more additives commonly used in the field. Such additives can for example be chosen from, and in a non-limiting manner, solvents, pigments, dyes, preservatives, biocides, and the like.

Among the solvents, very particularly preferred examples are alcohols, ethers, esters and glycols. In a particularly advantageous manner, the solvent is chosen from diethyl phthalate, ethylene glycol, propylene glycol, di-ethylene glycol, dipropylene glycol, poly-ethylene glycols, polypropylene glycols, and mixtures thereof, and even more advantageously from diethyl phthalate, dipropylene glycol, and mixtures thereof.

A typical odor masking agent composition includes (by weight based on total weight of odor masking agent):

- from 5% to 30% by weight of at least one mono-ester a1), chosen from iso-amyl acetate, ethyl methyl-2-butyrate, iso-amyl butyrate, phenylethyl acetate, ethyl caproate, benzyl acetate, hexyl acetate and mixtures thereof;

- from 20% to 60% by weight of at least one di- and/or tri-ester a2) chosen from ortho-phthalates, such as diethyl ortho-phthalate; citrates, such as triethyl citrate; and malonates, such as diethyl malonate, and mixtures thereof;

- from 5% to 25% by weight of at least one alcohol, preferably of at least two alcohols, more preferably of at least three alcohols, as described above under a3);

- from 1% to 10% by weight of at least one ketone, preferably at least two ketones, more preferably at least three ketones, as described above under a4); and

- from 1% to 10% by weight of at least one, preferably at least two, preferably a mixture of, terpenes referenced above under a5).

A representative, but non-limiting example of an odor masking agent is reproduced below, in which each of the components comprises one, several, or even all of the compounds listed:

Component a1): 16.00%

including benzyl acetate, hexyl acetate, iso-amyl acetate,

phenylethyl acetate, ethyl caproate, ethyl methyl-2-butyrate

Component a2): 50.00%

including diethyl malonate, diethyl phthalate

Component a3): 20.60%

including phenylethyl alcohol, citronellol, geraniol, linalool,

cis-3-hexenol

Component a4): 4.50%

including 1-(4-hydroxyphenyl) butan-3-one, alpha-irisone

Component a5): 7.00%

orange terpenes

Other: 1.90%

including citral, ethylmaltol, ethylmethyl phenylglycidate

These compositions are given by way of examples.

Application to drip fumigation

The present invention relates to the use of a formulation F as defined above, for the fumigation of soils and/or substrates. Preferably, said formulation F is administered to the soils and/or substrates to be treated by drop by drop.

The present invention also relates to a method of pesticide treatment by fumigation of soils and/or substrates, in which formulation F as defined above is administered by drop.

Thus, the fumigation of soils and/or substrates according to the invention is useful for the cultivation of fruits, vegetables, flowers and ornamental plants, in particular for tomatoes, strawberries, melons, cucumbers, eggplants, peppers , potatoes, carrots, pineapple, zucchini, watermelon, onions, garlic, vines, fruit trees and cut flowers.

Formulation F is particularly suitable for dropwise administration. It makes it possible to solubilize the fumigant and in particular the DMDS. The fumigant is solubilized in a stable way, which makes it possible to avoid its accumulation in the drippers, which clogs them. Formulation F is in particular stable for at least 30 minutes. In addition, it makes it possible to obtain a homogeneous diffusion of the fumigant over the entire surface to be treated and over the entire duration of the fumigation, without an area of ​​under or over dosage, which is obviously not desirable. In particular, if DMDS is used under the conditions of the invention, and in particular in the form of formulation F, with dropwise application, maximum efficacy can be obtained for this fumigant.

The treatment can easily be adapted by those skilled in the art depending on the crop to be treated, the nature of the soil and/or the substrate and the climatic conditions.

Drip administration can be performed by any conventional drip irrigation system. Such drip irrigation systems or devices (also called trickle irrigation systems or micro-irrigation or drip systems in English) are widely known and are generally used to supply water and possibly a drip liquid. irrigation such as liquid fertilizer to plants to be grown in the soil of farmland, plantations or other substrates. According to the invention, these systems are also called drop-by-drop fumigation systems when these deliver the fumigant formulation F according to the invention.

In addition to the conventional irrigation device, these systems comprise, for example, a supply and/or a reservoir for composition C as defined above and optionally a device for metering said composition C.

The composition C can be supplied by any means known per se, and for example from a reservoir containing it. The reservoir can be equipped with a pump and advantageously with a diving rod, as described in international application WO 2014/147034.

The drop-by-drop application is entirely preferably carried out by a drop-by-drop irrigation device comprising a device for metering said composition C. Thus, formulation F is advantageously prepared using the metering device by mixing with water, at the place where the fumigation is to take place. Dosing can be carried out using an Atex pump (pump for explosive atmosphere, for the use of flammable or easily flammable product) or a venturi system or a metering volumetric pump.

The metering is advantageously carried out using a metering volumetric pump, preferably a hydraulic volumetric proportional metering pump, preferably without electricity, such as those offered by the company Dosatron International® or by the company FLUIDEO®. Such a pump is for example described in application WO 2006/016032.

Thus, thanks to such a pump, the dosage of the formulation F is slaved to the water flow and can therefore be constant throughout the duration of the fumigation.

The drip fumigation system may in particular comprise drip lines (or pipes) connected to a main supply line and the main supply line can be connected to the metering device as mentioned above. According to one embodiment, the drip lines are spaced about 20 cm to 1.5 m from each other. Each drip line is notably equipped with drippers which can be spaced from 10 cm to 50 cm from each other and can have a flow rate of between 0.5 and 4 L/hour. The application time of formulation F according to the invention can be between 45 min and 5 h, preferably between 1 h and 2 h.

The amount of water can be between 10 and 50 L/m 2 , preferably between 10 and 30 L/m 2 , for example approximately 20 L/m 2 of the surface to be treated. The water pressure in the lines of drippers can be between 0.2 and 3 bar, preferably between 1 and 1.5 bar.

It is understood that the fumigation system according to the invention can be set up on the surface of the ground and/or of the substrate to be treated or be buried in the ground, for example between 5 cm and 2 m deep, preferably between 5 cm and 80 cm deep.

All of the lines comprising the drippers, or even the entire drop-by-drop fumigation system as well as the soil and/or substrate to be treated can be covered by a barrier film (i.e. impermeable to the vapors of the fumigant(s)) before application of formulation F. This prevents the dissipation of the fumigant(s) into the atmosphere and thus protects the operators and preserves the environment. Different types of barrier films, such as films of the SIF type (“semi-impermeable film” in English), VIF (“virtually impermeable film” in English), or TIF (“totally impermeable film” in English), are now used during treatment of soils and/or substrates by fumigation. Said barrier film may be a photocatalytic film as described in application WO 2013/030513 or a self-adhesive or tackifying film as described in application WO 2016/075392. For example, the films “BARRIER-FILM NFT54-195-1/2 CL2”, Film Accolade® and Film Paladin® marketed by Arkema can be used.

The present invention also relates to a kit for the fumigation of soils and/or substrates by drop-by-drop comprising composition C as defined above, as well as a device for metering said composition C, and optionally a drop device drip as defined above (including in particular lines of drippers and a water and composition C supply system).

Said kit makes it possible to prepare, from composition C, formulation F according to the invention, by dosage, and optionally its application with the drop by drop system.

Said kit may optionally comprise a barrier film as mentioned above.

EXAMPLES

Example 1: Formulation F with DMDS according to the invention and comparison

A composition C is mixed with water.

Composition C consists of approximately:

- 94.75% by weight of DMDS;

- 0.25% by weight of an odor masking agent; and

- 5.00% by weight of surfactants based on calcium salts of C 10 -C 13 alkyl derivatives of benzene sulphonic acid.

We get the following results:

The percentages are expressed relative to the total volume of water

The Formulations F according to the invention make it possible to obtain a good emulsification of the DMDS and this in a stable manner.

Up to a dose of approximately 0.25% by volume of composition C, a clear and stable microemulsion is obtained for at least 30 minutes.

Between >0.25% and 0.4% by volume of composition C, an emulsion is obtained which becomes slightly cloudy and which remains stable for at least 30 minutes.

For doses of composition C greater than 0.40% by volume, emulsification is poor and the emulsion is not stable.

Example 2: Treatment by fumigation according to the invention

The efficacy of DMDS in formulation F according to the invention, alone or in combination with another fumigant, was tested on carnations grown on greenhouse cultivation plots in Turkey.

I. Material and Method:

The trial was carried out using an experimental design of 6 randomly chosen plots, treated with 6 different treatments, with 4 tests per treatment. The size of the plots was 50 m 2 and the amount of water used 20 L/m 2 .

DMDS and/or metam sodium were applied with water through a drip irrigation system (DMDS with a Dosatron® pump and then metam sodium with an electric pump) one month before planting the carnations.

All the plots treated with DMDS were covered for 4 weeks with a totally impermeable film (TlF); the plot treated with metam sodium was covered with a polyethylene film.

The treatments were as follows:

The composition C used consists of approximately:

- 94.75% by weight of DMDS;

- 0.25% by weight of an odor masking agent; and

- 5.00% by weight of surfactants based on calcium salts of C 10 -C 13 alkyl derivatives of benzene sulphonic acid.

For metam sodium, an aqueous solution (at 510 g/L of metam sodium) is injected into a stream of water. The injection of metam sodium takes place after the application of DMDS.

Table 2: Concentrations used

The concentrations are expressed in % by volume relative to the total volume of water.

II. Observations and Statistical Analysis:

Soil evaluation was carried out at 90 and 180 days after planting the carnations.

The percentage of mortality was evaluated in 300 plants per plot. The data was processed with Abbot's formula and the percentage effectiveness of the treatments was calculated. The analysis of variance was performed with Duncan's test (0.05).

In the test plots, samples were taken from the infected carnation. Using isolation studies, Fusarium spp. has been determined to be the infectious disease causing root rot of carnations.

III. Results :

At 90 days after planting, the following treatments had the best efficacy:

- Formulation 1: 79.4% efficacy;

- Formulation 3: 84.8% efficacy; and

- Formulation 4: 90.9% efficiency.

At 180 days after planting, all fumigation treatments had significantly better efficacy against Fusarium spp. that the untreated control and all DMDS treatments demonstrated significantly better control of Fusarium spp. compared to metam sodium applied alone at 1200 L/ha.

Table 3; Percentage of mortality and effectiveness of fumigant treatments applied by drip on

** DAP: Days after planting

During harvest, the best yields were obtained with formulations 1, 3 and 4 as shown in the table above.

Table 4: Tors yield of the harvest and variation in yield compared to untreated plots

FINDINGS

When the concentration of composition C is between 0.10% and 0.40% by volume (relative to the total volume of water) in the drop by drop:

- the application takes place perfectly, with excellent dissipation in the soil of the formulations;

- the distribution of the formulations by dosing with the drop by drop system allows a constant and homogeneous DMDS concentration throughout the fumigation process; and

- DMDS formulations are stable throughout the fumigation process.

The formulations such as according to the invention are therefore completely suitable for drop by drop application and allow effective and homogeneous pesticide treatment, without failure of the fumigation equipment.

In addition, tests were carried out with formulations whose concentration was greater than 0.40% by volume of composition C.

When the concentration of composition C is strictly greater than 0.40% by volume (compared to the total volume of water) in the drop by drop:

The application was stopped by a drop in pressure in the dripper lines which expanded. Indeed, the lines of drippers (in PE for polyethylene, or in PVC for polyvinyl chloride) swell on contact with the supernatant DMDS (which is therefore less well dissolved) which is not compatible with these materials. The lines of the drippers swell, dilate, which can cause the escape of fumigant under the plastic film.

Drippers clog. This clogging can be induced can be induced:

- by the chemical degradation of plastic materials upstream of the drippers

- by the swelling of a membrane present in "self-compensated" drippers (this system allows a stable flow rate of the drippers).

Treatment by drip fumigation is therefore difficult or even impossible under these conditions.

CLAIMS

1. Method of pesticide treatment by fumigation of soils and/or substrates, in which a formulation F is administered by drop by drop;

said formulation F comprising water and between 0.10% and 0.40% by volume of a composition C, relative to the total volume of water of formulation F, and

said composition C comprising:

- at least 80% by weight, preferably at least 90% by weight, of at least one fumigant compound relative to the total weight of composition C;

- between 0.1% and 20% by weight of at least one surfactant relative to the total weight of composition C; and

- optionally an odor masking agent.

2. Method according to claim 1, wherein said formulation F is an emulsion.

3. Method according to any one of the preceding claims, in which formulation F comprises between 0.10% and 0.30% by volume of said composition C, relative to the total volume of water of formulation F.

4. Method according to any one of the preceding claims, in which the said fumigant compound is chosen from the compounds of general formula (1) below:

RS(0) n -S x -R' (1)

in which R is chosen from an alkyl radical, linear or branched, containing from 1 to 4 carbon atoms, and an alkenyl radical, linear or branched, containing from 2 to 4 carbon atoms; n is equal to 0, 1 or 2; x is an integer chosen from 0, 1, 2, 3 or 4, preferably x represents 1, 2, 3 or 4;

R' is chosen from an alkyl radical, linear or branched, containing from 1 to 4 carbon atoms, and an alkenyl radical, linear or branched, containing from 2 to 4 carbon atoms or, only when n = x = 0, a hydrogen or alkali metal atom.

5. A method according to any preceding claim, wherein the fumigant compound is dimethyl disulfide.

6. Method according to any one of the preceding claims, in which composition C comprises:

- at least 90% by weight of dimethyl disulphide relative to the total weight of composition C,

- between 1% and 10% by weight of at least one surfactant relative to the total weight of composition C, and

- optionally between 0.1% and 0.5% by weight of an odor masking agent relative to the total weight of composition C.

7. Method according to claim 6, in which the DMDS is administered in a mixture or separately with another fumigant compound chosen from the group consisting of: 1,3-dichloropropene, sulfuryl fluoride (S0 2 F 2 ), phosphine, methyl iodide, chloropicrin (CI 3 C-NO 2 ), Metam-sodium (CH 3 -NHCS 2 Na), sodium tetrathiocarbonate (Na 2 CS 4 ), isothiocyanate methyl (CH 3 NCS), Dazomet (tetrahydro-3,5-dimethyl-1,3,5-thiadiazine-2-thione), AITC (Allyl Iso thio cyanate) or EDN (ethanenitrile) .

8. Method according to any one of the preceding claims, in which the drip application is carried out by a drip irrigation device comprising a device for metering said composition C.

9. Formulation F comprising water and between 0.10% and 0.40% by volume of a composition C, relative to the total volume of water of formulation F, and

said composition C comprising:

- at least 80% by weight, preferably at least 90% by weight, of at least one fumigant compound relative to the total weight of composition C;

- between 0.1% and 20% by weight of at least one surfactant relative to the total weight of composition C; and

- optionally an odor masking agent.

10. Use of a formulation F according to any one of claims 1 to 9, for the fumigation of soils and/or substrates, said formulation F preferably being administered to the soils and/or substrates by drop.

11. Kit for the fumigation of soils and / or substrates by drop comprising composition C as defined in any one of claims 1 to 9, as well as a device for metering said composition C.