MIXTURE OF VOLATILE ORGANIC REPELLENT COMPOUNDS AND COMPOSITION COMPRISING IT

Abstract

The present invention relates to a mixture of volatile organic compounds (VOCs) for insect repellency, in particular for aphids, which comprises as VOCs at least linalool and eugenol. The invention also relates to an insect repellent composition comprising said mixture, and its use in agriculture, in particular in fields for protecting plants against damage caused by insect pests.

Description

Title of the invention: REPELLENT MIXTURE OF VOLATILE ORGANIC COMPOUNDS AND COMPOSITION COMPRISING IT FIELD OF THE INVENTION

[0001] The present invention relates to a mixture of volatile organic compounds (VOCs) repellent for insects, in particular for aphids, which comprises as VOCs, at least linalool and eugenol. The invention also relates to an insect repellent composition comprising said mixture, and its use in agriculture, in particular in fields for protecting plants against damage caused by insect pests. BACKGROUND OF THE INVENTION

[0002] Protecting crops against insect pests essentially involves the use of insecticide molecules which have the advantage of effectively eliminating pests, but the disadvantage of also eliminating other insects, such as pollinators, and of forming residues which pollute the surrounding soil and water tables. This is particularly the case with neonicotinoids which act at low doses on the central nervous system of insects, both harmful and pollinators.

[0003] Legislation in various countries has led to a ban on the use of these insecticides, but it is important to be able to provide concrete and effective alternatives to insecticides to enable farmers to produce more sustainably.

[0004] A particular problem concerns the protection of crops against aphid attacks, and in particular the protection of sugar beet crops to prevent the disease known as sugar beet yellows caused by the beet yellows virus (BYV), which is carried by aphids. It is therefore essential to be able to repel aphids so that they do not reach beet crops, thereby preventing the transmission of the virus and the development of the disease in beet crops.

[0005] The ability of certain VOCs to repel insects is known (WO 2006 / 040766), in particular through the use of essential oils, complex mixtures of VOCs (WO 1996 / 039827; Kowalska, J. et al., Molécules, 2021; Deletre et al., 2015; Obeng-Ofori et al., 1997; Araujo et al., 2012; Zhang et al., 2013) or certain mixtures which have repellent or attractive properties (EP 3 031 322; EP 3 874 948). Their use to repel aphids is also described (Dardouri, Tarek, et al., Agricultural and Forest Entomology, 2019; Dardouri, Tarek, et al., Pest management science, 2019; Dardouri, Tarek, et al., IOBC-WPRS Bull, 2017; Hori, Masatoshi, Journal of Chemical Ecology, 1998).

[0006] Some major compounds in these complex mixtures have been identified. Eugenol has been identified as a repellent for cockroaches and other beetles (Obeng-Ofori D and Reichmuth C, 1997; Zhang QH et al., 2013; WO 2003 / 051121).

[0007] However, the physicochemical properties of each individual molecule do not allow for effective field use, either because they are rapidly degraded, like cinnamaldehydes, evaporate too quickly or have too limited an action. Similarly, VOC associations are not obvious when we note that the association of 2 VOCs can lead to a drastic reduction in their effectiveness (Dardouri & al. 2018; Bruce & Pickett, 2011). Repulsion can also be associated with the presence of minor VOCs, which are sometimes difficult to detect (McCormick et al., 2014; Bruce et al. 2005). Finally, known application methods often involve trap systems that do not allow for standard use in agriculture.

[0008] It is an object of the present invention to provide an effective biocontrol solution for use in agriculture. BRIEF DESCRIPTION OF THE INVENTION

[0009] The present invention relates to a mixture of volatile organic compounds (VOCs) which comprises at least linalool and eugenol.

[0010] According to one embodiment, the linalool / eugenol weight ratio ranges from approximately 1 / 4 to approximately 2 / 3.

[0011] The invention also relates to a mixture of VOCs which comprises at least linalool, eugenol and trans-cinnamaldehyde.

[0012] The present invention also relates to a repellent composition which comprises said mixture of VOCs and a carrier suitable for its use in agriculture.

[0013] The invention also relates to the use of the VOC mixture or the repellent composition in agriculture. DETAILED DESCRIPTION OF THE INVENTION

[0014] Definitions

[0015] By “volatile organic compound” or “VOC” is meant organic compounds that are volatile at room temperature.

[0016] By “room temperature” we mean a temperature ranging from 15 to 40°C, more generally from 20 to 30°C.

[0017] By "VOC mixture" is meant a composition consisting of VOCs chosen from kairomones and allomones. It may include negligible traces of non-volatile impurities. The VOC mixture consists of at least 99% VOCs, more generally 100% VOCs. The VOC mixture is a "syn "thetic" or also called "manufactured", that is to say that it is not found as such in nature. It is obtained by mixing pure VOCs or already in mixtures with other VOCs.

[0018] “Kairomones” are VOCs produced by an emitting living organism, which produce a favorable effect for another living organism called a receiver, when they are released into the environment.

[0019] “Allomones” are VOCs produced by individuals of a first so-called emitting species which induce in individuals of another so-called receiving species a reaction favorable to the emitting species.

[0020] By “support” we mean a support allowing the conservation of the mixture of VOCs, their dosage, and their use.

[0021] By "support suitable for its use in agriculture" is meant a support which is furthermore suitable for the application of the repellent composition according to methods usual in agriculture and the release of VOCs after application.

[0022] By "use in agriculture" or "use in agriculture" is meant the application of the VOC mixture or the repellent composition in fields near cultivated plants, on the plants or at the base of the plants. By "in the fields" is meant both in a field in the open air and in a greenhouse. These are growing conditions in an uncontrolled atmosphere (in a field) or a poorly controlled atmosphere (in a greenhouse), with only certain temperature and / or humidity parameters generally being controlled.

[0023] Unless otherwise indicated, percentages, contents and ratios are expressed by weight.

[0024] An indication of numerical ranges by the end points is intended to include all numbers included in that range (for example, a recitation of 1 to 5 includes, but is not limited to, 1, 1.25, 1.5, 1.75, 2, 2.45, 2.75, 3, 3.80, 4, 4.32, 4.45, and 5).

[0025] The term "about" is used herein explicitly or implicitly. Each quantity given in this description refers to the actual given value, and to the approximation of that given value that would be reasonably deduced based on ordinary skill in the art, including equivalents and approximations due to experimentation and / or measurement conditions for that given value. In general, the term "about" in the context of a given value refers to said value and a range that encompasses said value by + / - 5% of said given value, particularly by + / - 1%.

[0026] VOC Mixture

[0027] The VOCs used in the mixture according to the invention may be of natural origin, extracted from plants in particular, or synthetic. Whether they are of natural or synthetic origin, the VOCs used in the mixture according to the invention have a purity of at least 95%, advantageously at least 96%, at least 97%, at least 98%, at least 99%.

[0028] The VOC mixture according to the invention comprises at least linalool and eugenol.

[0029] Linalool (Cas No.: 78-70-6) is a VOC of formula:

[0030] Linalool is a naturally occurring product found abundantly in natural oils such as bergamot, lavender, or rosewood essential oils. It is also produced by chemical synthesis.

[0031] Eugenol (Cas No.: 97-53-0) is a VOC with the formula H3CO HO

[0032] Eugenol, also known as 4-allyl-2-methoxyphenol, is a naturally occurring product found abundantly in natural oils such as clove oils. It is also produced by chemical synthesis.

[0033] According to the invention, the VOC mixture comprises less linalool than eugenol.

[0034] According to one embodiment, the linalool / eugenol weight ratio ranges from approximately 1 / 4 to about 2 / 3, and in particular about 2 / 7, about 1 / 3, about 3 / 8, about 2 / 5, about 3 / 7, about 4 / 9, about 1 / 2, about 5 / 9 and about 3 / 5. In particular, the linalool / eugenol weight ratio is between any of these fractions, in particular between about 2 / 7 and about 1 / 2, between about 1 / 3 and about 5 / 9, between about 3 / 8 and about 3 / 5. According to a particular embodiment, the linalool / eugenol weight ratio is at least about 1 / 3, in particular at least about 3 / 8, more particularly at least about 2 / 5. According to another particular embodiment, the linalool / eugenol weight ratio is less than about 1 / 2, in particular less than about 4 / 9. According to another particular embodiment, the linalool / eugenol weight ratio ranges from about 3 / 8 to about 4 / 9. Advantageously, the linalool / eugenol weight ratio is about 2 / 5 or about 3 / 7.

[0035] According to a particular embodiment, the VOC mixture comprises at least linalool, eugenol and cinnamaldehyde, in particular trans-cinnamaldehyde.

[0036] Trans-cinnamaldehyde (Cas No.: 104-55-2) is a VOC of formula:

[0037] Trans-cinamaldehyde or cinnamic aldehyde, also known as 3-phenylpropenal, is a naturally occurring product found abundantly in natural oils such as cinnamon oil. It is also produced by chemical synthesis.

[0038] The content of trans-cinnamaldehyde in the VOC mixture is less than or equal to the content of the linalool + eugenol mixture, preferably less.

[0039] According to one embodiment, the weight ratio trans-cinna-maldehyde / (linalool+eugenol) ranges from about 2 / 7 to about 1 / 1, and in particular about 1 / 3, about 3 / 8, about 2 / 5, about 3 / 7, about 4 / 9, about 1 / 2, about 5 / 9, about 3 / 5 and about 2 / 3. In particular, the weight ratio trans-cinna-maldehyde / (linalool+eugenol) is between any one of these fractions, in particular between about 1 / 3 and about 3 / 5, between about 3 / 8 and about 5 / 9, between about 2 / 5 and about 1 / 2. According to a particular embodiment, the weight ratio trans-cinnamaldehyde / (linalool+eugenol) is at least about 1 / 3, in particular at least about 3 / 8, more particularly at least about 2 / 5. According to another particular embodiment, the weight ratio trans-cinnamaldehyde / (linalool+eugenol) is less than approximately 5 / 9, in particular less than approximately 1 / 2, even more particularly less than approximately 4 / 9.According to another particular embodiment, the weight ratio trans-cinnamaldehyde / (linalool+eugenol) ranges from approximately 2 / 5 to approximately 1 / 2. Advantageously, the weight ratio trans-cinnamaldehyde / (linalool+eugenol) is approximately 3 / 7.

[0040] In this definition, the quantity of linalool and eugenol in the linalool+eugenol+trans-cinnamaldehyde mixture is preferably according to a linalool / eugenol weight ratio as defined above.

[0041] The VOC mixture according to the invention may comprise other VOCs chosen from kairomones and allomones. Mention will be made in particular of geraniol and caryophyllene.

[0042] According to a particular embodiment, the content of linalool and eugenol (linalool + eugenol) is at least 30% by weight of the total weight of the VOC mixture, more particularly at least 35%, 40%, 45% or 50% by weight. According to a more particular embodiment, the content of linalool and eugenol is at least 60% by weight of the total weight of the VOC mixture, more particularly at least 65% to 100%.

[0043] According to one embodiment, the VOC mixture comprises: a. 5 to 40% of linalool, in particular 15 to 35% b. 25 to 80% of eugenol, in particular 40 to 75% c. 0 to 50% of trans-cinnamaldehyde, in particular 10 to 40%, the total a+b+c being less than or equal to 100% and the relative contents of each constituent being defined above.

[0044] According to a particular embodiment of the invention, the VOC mixture comprises: a. 15 to 25% linalool, especially about 20% b. 45 to 55% eugenol, especially about 50% c. 25 to 35% trans-cinnamaldehyde, especially about 30% the total a+b+c being equal to 100%.

[0045] When the total a+b+c is less than 100%, the mixture comprises other VOCs, more particularly other kairomones or allomones described above in relative quantities whose addition to a+b+c equals 100%.

[0046] Mention will in particular be made of a composition comprising: a. 5 to 20% linalool, b. 25 to 40% eugenol, c. 30 to 45% trans-cinnamaldehyde, d. 5 to 15% geraniol, and e. 5 to 15% caryophyllene, the total a+b+c+d+e being equal to 100%.

[0047] Repellent Composition

[0048] The repellent composition according to the invention comprises the mixture of VOCs and a support. Said support can be solid and is particularly suitable for use in agriculture.

[0049] The composition is repellent in the sense that the mixture of VOCs it contains is suitable for repelling insects that are pests of crops.

[0050] According to a preferred embodiment, the repellent composition is in solid form, in particular in the form of powder or granules with a particle size of 0.0001 to 6 mm.

[0051] The powders advantageously have a particle size of 0.0001 to 0.5 mm.

[0052] The granules advantageously have a particle size of approximately 1 to approximately 5 mm. diameter, especially about 1 to about 3 mm in diameter, in particular about 1.5 to about 3 mm in diameter, for example 1.75, 2, 2.25, 2.35, 2.5, 2.6, 2.75 or 3 mm in diameter. The granules may be spherical or oblong in shape. In this case, the length is longer than the diameter and generally ranges from about 3 to about 6 mm, in particular from about 3 to about 5 mm, for example 3.25, 3.4, 3.5, 3.6, 3.75, 3.8, 4, 4.25, 4.5, 4.75, 4.85 or 5 mm. The diameter and length values ​​are given as average values ​​for the granules according to the invention.

[0053] According to one embodiment, the VOC mixture content in the repellent composition is from about 0.1 to about 20% by weight, advantageously from about 1 to about 10% by weight. In particular, the VOC content in the repellent composition is 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 11, 12, 13, 14, 15, 16, 17, 18, 19 or 20% by weight. Mention will in particular be made of amounts of at least about 1%, about 2%, about 3%, about 4%, about 5%, about 6%, about 7%, about 8%, about 9%, or at least about 10% by weight. Also included are amounts less than or equal to about 20%, about 19%, about 18%, about 17%, about 16%, about 15%, about 13%, or less than or equal to about 12% by weight.

[0054] Value ranges for the VOC amounts may be 1 to 5% by weight, 2 to 6%, 3 to 7%, 4 to 8%, 5 to 9%, 6 to 10%, 7 to 11%, 8 to 12%, 9 to 13%, or any value range between about 0.1% and about 20% by weight.

[0055] According to a particular embodiment, the repellent composition comprises at least 10% of VOC mixture, in particular from approximately 10% to approximately 16% of VOC.

[0056] The VOC content in the composition will depend in particular on the support used.

[0057] The support, also called matrix, is suitable for its use in agriculture, that is to say it allows the application of the repellent composition in the fields near the cultivated plants, on the plants or at the feet of the plants according to usual agronomic methods.

[0058] The support is inert with respect to the VOC mixture, that is to say that it does not produce reactions with the VOCs of the mixture in a substantial manner such that the mixture would be modified during the preservation and storage of the repellent composition.

[0059] The VOC mixture can be dissolved in an inert matrix, absorbed or adsorbed onto such a matrix, depending on the type of support used.

[0060] Supports for such solid compositions are well known and include in particular mineral supports such as clays, talc, oxides or hydroxides, carbonates, or silica and silicates, or organic supports such as lactose or waxes.

[0061] The support may also comprise usual binding compounds, such as cellulose derivatives, starch, dextrins, gums, polymers or oils.

[0062] It may also include other additives usual for the preparation of powders or granules, such as colorants, preservatives, anti-foaming agents, anti-caking agents.

[0063] The granules may also comprise a coating.

[0064] The preparation of the repellent compositions according to the invention is carried out according to the usual methods of preparing powders and granules, coated or not.

[0065] According to another embodiment, the support is a diffusion matrix.

[0066] A VOC diffusion matrix is ​​a carrier material that is used to controllably release VOCs.

[0067] The diffusion matrices must have sufficient porosity to allow a gradual release of the VOCs, capable of retaining them in such a way as to avoid too rapid or too slow release. They must be non-toxic and compatible with the substances to be diffused.

[0068] These diffusion matrices are known to those skilled in the art and include in particular supports made of paper, cardboard, plastic, which are generally impregnated with the VOC mixture. Other materials can also be used, such as polymers, porous ceramics or materials based on natural fibers.

[0069] There are several types of diffusion matrices for VOC mixtures such as slow-release diffusers, for example capsules, sachets or impregnated strips which slowly release the substance into the air, or electric diffusers which use heat or vibrations to diffuse the VOCs, or spray diffusers which vaporize the VOCs in the form of fine droplets into the air, or gel diffusers (gel or paste) which gel solidifies at room temperature and slowly releases the VOCs into the air, or other types of diffusion media for VOCs, such as ultrasonic diffusers, membrane diffusers, pellet diffusers, etc.

[0070] The shape and composition of the support will be chosen for its adaptation to the intended agricultural use.

[0071] Use in Agriculture

[0072] The VOC mixture and the repellent composition according to the invention are particularly suitable for use in agriculture, in particular for repelling insect pests, keeping them away from the plants that one seeks to protect and in the vicinity or on which the repellent composition or the VOC mixture has been applied.

[0073] The invention therefore relates to the use in agriculture of a mixture of VOCs or of a repellent composition according to the invention, to protect plants against damage caused by insect pests.

[0074] By "protecting plants against damage caused by insect pests" is meant the action of repelling insect pests on cultivated plots. This action can be measured by the reduction in the number of aphids on a cultivated plot compared to an untreated plot. This number of aphids must be reduced by at least 30%, advantageously by at least 50% or more. In particular, at least 60% of the aphids are repelled.

[0075] The invention therefore also relates to a method for protecting plants against damage caused by insect pests, said method consisting of applying to the plant and / or near the plant, an appropriate quantity of repellent composition according to the invention.

[0076] The method of application will depend on the plant being protected. It may be done by passive diffusion (application of a composition which allows the controlled release of the mixture of VOCs over time) or by active diffusion (direct application of the VOC mixture on the plant or near the plant).

[0077] Thus, for a crop plant, the application will be on the plant and / or on the soil near the plant. For trees or shrubs, the application will be on the plant or near the aerial parts of the plant.

[0078] The application is carried out according to the usual methods used in agriculture, depending on whether the product applied, composition or mixture of VOCs, is in liquid or solid form. For the particular method of composition in solid, powder or granule form, the application is carried out with usual means of spreading and / or applying powders or granules on or at the base of the plants.

[0079] It can be made alone, or combined with other products for improving and / or controlling pests and other diseases of cultivated plants. Advantageously, the application of the repellent composition according to the invention makes it possible to limit, and preferably to avoid, the use of insecticides.

[0080] For cultivated plants, "near the plant" generally means a distance between the area of ​​application of the repellent composition and the stem of the plant which will depend in particular on the surface of the soil covered by the leaves at the development stage of the application. It ranges in particular from 0 (on contact) to approximately 80 cm.

[0081] For trees or shrubs, the VOC mixture may be applied by means of passive diffusers placed near the aerial parts of the trees or shrubs, or even within these aerial parts for trees or on the trunks of the trees. Nearby means that the passive diffuser is placed at a distance of up to 1 m from the woody parts (trunks and branches) of the trees or shrubs.

[0082] The appropriate quantity of repellent composition applied to the plot will depend on its VOC content and the matrix used, its capacity to diffuse the VOC mixture in a controlled manner over time. It could be between 100 g / ha and 3 kg / ha depending on the composition used.

[0083] The composition according to the invention is applied as needed for prevention when aphids are likely to appear or for treatment after the appearance of aphids on the plants.

[0084] According to a particular method suitable for the protection of cultivated plants, the repellent composition is applied in preventive mode as soon as the seedlings emerge (cotyledon stage). Depending on the pressure exerted by insects during the growth of the plants, the application of the repellent composition may be repeated at least once.

[0085] The mixture according to the invention is particularly suitable for repelling aphids and therefore for protecting plants against the damage caused by aphids. Aphids are the cause of significant losses in cultivated plants. (https: / / www6.inrae.fr / encyclopedie-pucerons / Pucerons-et-agriculture). Plants susceptible to the ravages of aphids are field crops, market garden plants, ornamental plants or trees or shrubs.

[0086] Among the cultivated plants, we will mention the Apiaceae (Umbelliferae), such as carrots, celery or root or aromatic plants such as parsley, fennel, angelica, cumin; the Asteraceae, including oilseeds such as sunflower, oilseed plant or market garden plants such as lettuce, chicory, endive, artichoke, salsify, scorzonera, or aromatic, medicinal or ornamental plants such as asters, or chrysanthemums; the Brassicaceae (Cruciferae), including oilseeds such as rapeseed, or vegetable brassicaceae; the Chenopodiaceae such as beets, spinach, chard or cardoon; Cucurbitaceae, such as melons, squash, zucchini, cucumbers, gherkins, pumpkins, watermelons; Fabaceae (legumes), grown as field crops such as clover, sainfoin, alfalfa, pea vetch, protein peas, field beans or lupin, or grown as market garden crops such as beans, peas, lentils or broad beans;Liliaceae (Aliaceae), such as leek, onion, shallot, garlic or asparagus; Poaceae, including straw cereals, wheat, barley, oats or rye, forage grasses, cocksfoot, fescue, timothy or ryegrass or corn; Rosaceae, fruit trees including apricot, cherry, peach, pear, apple, plum, strawberry, raspberry or blackberry; Solanaceae such as potatoes, tomatoes, eggplant and pepper.

[0087] The mixture according to the invention is particularly suitable for the protection of Chenopodiaceae, in particular beets, more particularly sugar beets.

[0088] Among the aphids, pests of crops of these plants, we will mention the aphids of the genera Acyrthosiphon (Acyrthosiphon pisum, Acyrthosiphon malvae), Aphis (Aphis lambersi, Aphis spiraecola, Aphis fabae, Aphis gossypii, Aphis nastutii, Aphis craccivora, Aphis forbesi, Aphis frangulae), Aulacorthum (Aulacorthum solani, Aulacorthum circumflexum), Brachycaudus (Brachycaudus helichrysi), Brevicoryne ( Brevicoryne brassicae), Cavariella (Cavariella aegopodii), Chaetosiphon (Chaetosiphon (Pentatrichopus) fragaefolii), Diuraphis (Diuraphis spp). Dysaphis (Dysaphis apifolia, Dysaphis crataegi, Dysaphis plant aginea), Hyadaphis (Hyadaphis foeniculi, Hyadaphis passerini), Lypaphis (Lipaphis erysimi), Macrosiphum (Macrosiphum eu-phorbiae), Megoura (Megoura viciae), Metopolophium (Metopolophium dirhodum, Metopolophium festucae), Myzus (Myzus persicae, Myzus ascalonicus, Myzus ornatus), Nazonovia (Nazonovia ribisnigrii), Neactaphis (Nearctaphis bakeri).Neotoxptera (Neotoxoptera formosana, Neotoxoptera oliveri), Rhopalosiphum (Rhodobium porosum), Rhopalosiphoninus (Rhopalosiphoninus staphyleae, Rhopalosiphum padi, Rhopa-losiphum insertum, Rhopalosiphum maidis, Rhopalosiphoninus laty siphon), Schizaphis. (Schizaphis graminum), Semiaphis (Semiaphis dauci). Sipha (Sipha (Rungsia) elegans, Sipha (Rungsia) maydis), Sitobion (Sitobion avenue, Sitobion fragariae), Smyn-thurodes (Smynthurodes betae), Trama (Trama spp) and Therioaphis (Therioaphis trifolii)

[0089] The mixture of VOCs or the composition according to the invention can be used alone or in combination with other repellent or attractive compounds or compositions, whether VOCs or other products known as pheromones.

[0090] In addition to the damage caused by the development of the insects themselves, aphids are also vectors for the transmission and propagation of viruses which increase the damage caused to plants. (https: / / www6.inrae.fr / encyclopedie-pucerons / Pucerons-et-agriculture / Virus / Pucerons-vecteurs). This is particularly the case for beet yellows viruses (BYV and BMYV).

[0091] In this case, the aphids vectors of virus transmission are in particular Myzus persicae, M. ascalonicus, Aphis fabae, Aulacorthum solani. The VOC mixture according to the invention is particularly suitable for repelling aphids of the genus Myzus, in particular of the species Myzus persicae.

[0092] According to a particular embodiment, the mixture of VOCs and the composition according to the invention are particularly suitable for the protection of beets, in particular sugar beets, against aphids and damage caused by beet yellows viruses.

[0093] The invention therefore relates to the use in agriculture of a mixture of VOCs or of a repellent composition according to the invention, to protect beets, in particular sugar beets, against damage caused by aphids, in particular of the species Myzus persicae.

[0094] The invention also relates to a method for preventing damage caused by aphids to beet crops, in particular sugar beets, said method comprising the application to the cultivated beet plants, before or at the time of the appearance of the aphids, of an appropriate quantity of VOC mixture according to the invention, or of a repellent composition according to the invention.

[0095] The invention also relates to the use of the VOC mixture defined above for repelling aphids, in particular of the genera Aphis and Myzus, more particularly of the genera Myzus, even more particularly of the species Myzus persicae.

[0096] The invention also relates to a method for repelling aphids, in particular of the genera Aphis and Myzus, more particularly of the genera Myzus, even more particularly of the species Myzus persicae, said method comprising the diffusion in the vicinity of said aphids of a mixture of VOCs as defined above or of a composition of VOCs as defined previously. Brief description of the drawings

[0097] [Fig.l]: [Fig.l] represents the average results of winged aphid counts (on the ordinate) on beet plants grown in the field at different stages of development (on the abscissa) of 2, 4, 6 or 8 leaves for untreated plots (Control) or treated with a mixture according to the invention (Mixture H).

[0098] [Fig.2]: [Fig.2] represents the average results of counts of apterous aphids (on the ordinate) on beet plants grown in the field at different stages of development (on the abscissa) of 2, 4, 6 or 8 leaves for plots not treated (Control) or treated with a mixture according to the invention (Mixture H). An aphicide treatment is carried out between the 6 and 8 leaf stages. EXAMPLES

[0099] The examples below illustrate the invention and its implementation for different VOC compositions on sugar beet plants in the presence of aphids.

[0100] Tests were carried out in the laboratory, under conditions modeling a natural environment, and other tests were carried out in the open field.

[0101] Example 1: Comparison of repellent effects in the laboratory after 24 hours

[0102] The no-choice test is used to evaluate the repellent effect of VOCs on aphids in the presence of the host plant. It is carried out using an airflow test cage, in which aphids are exposed to the repellent VOCs and the host plant. The aphids are then observed to determine their choice between remaining on the plant or leaving it, thus measuring the repellent effect of VOCs on their colonization behavior.

[0103] Materials and methods

[0104] Plant material

[0105] Sugar beet plants of the Arum variety are grown to the 2-leaf stage in individual pots 8 cm high and 7x7 cm wide. The growing conditions are maintained at a temperature of 22°C ± 1°C, full spectrum lighting and a photoperiod of 16 hours long day and 8 hours short night to ensure standardized and reproducible development of the study plants.

[0106] Animal material

[0107] Adult individuals of the wingless green aphid (Myzus persicae) are reared on sugar beet var. Arum under controlled conditions of temperature (22°C ± 1°C) and lighting (full spectrum with a long day photoperiod of 16 hours and a short night of 8 hours) to ensure standardized and reproducible reproduction of the study subjects.

[0108] In order to minimize variations in the age of the tested individuals, cohorts of aphids are reared by synchronizing their age to approximately one week before the start experiences.

[0109] Chemical products

[0110] VOCs are purchased from Sigma-Aldrich: Linalool (CAS No. 78-70-6, >97%), Eugenol (CAS No. 97-53-0, >98%), Trans-cinnamaldehyde (CAS No. 104-55-2, >99%), Geraniol (CAS No. 106-24-1, >98%) and Carophylene (CAS No. 87-44-5>98%). [YES] VOC Mixtures

[0112] Several VOC mixtures were prepared, identified in Table 1 below.

[0113] The content of each VOC in the mixture is given in proportion by weight relative to the total mixture reported at 10.

[0114] [Tables 1] Mixture A* B c* D* E* F* GH Linalool 5 3 5 3 0 0 2 1 Eugenol 5 7 0 0 5 3 5 3 Trans-Cinnamaldehyde 0 0 5 7 5 7 3 4 Geraniol 0 0 0 0 0 0 0 1 Caryophylene 0 0 0 0 0 0 0 1 * Controls

[0115] VOC Diffuser - Repellent Compositions

[0116] Rapeseed wax beads are used to diffuse VOCs. These beads have a volume of 0.17 ml, a weight of 150 mg and contain a VOC content of 2.5%.

[0117] Experimental device

[0118] In order to carry out non-choice tests, transparent plexiglass enclosures are arranged on a transparent plexiglass plate. A constant air flow is created using an air pump at the inlet and outlet of the enclosure, with an air flow of 1.5 L / min at the inlet and 1 L / min at the outlet, thus making it possible to maintain a constant air flow inside the enclosure.

[0119] In order to avoid any contamination of the air inside the enclosure by foreign VOCs, the inlet air is filtered through an activated carbon filter. In the center of the enclosure, 3 beet plants grown in individual pots are arranged at equal distance from the walls of the enclosure. Aphids are transferred to each plant using a watercolor brush with a number of 10 aphids per plant. After a stabilization period of 1 hour, the number of aphids present on the beet leaves is counted using an appropriate method. The VOCs are incorporated into wax beads and are placed in the middle of the enclosure. After a period of 24 hours, the number of aphids remaining on each plant is counted again to evaluate the effect of VOCs on their colonization behavior.

[0120] Results

[0121] The repellent effects were tested in the laboratory for the different mixtures and for linalool (Li), eugenol (Eu) and trans-cinnamaldehyde (TransC) alone.

[0122] The results are reported in Table 2 below.

[0123] [Tables2] Repulsion Rate Li* 14.64 Eu* 14.50 TransC* 17.50 A* 15.00 B 24.60 C* 19.40 D* 6.80 E* 12.22 F* 13.50 G 19.40 H 20.36

[0124] A repellency rate value greater than or equal to 19 is a demonstration of a marked aphid repellency effect.

[0125] A value greater than 19 will be noted for the control mixture C. However, the behavior of cinnamaldehyde and the contradictory effects observed when it is combined with other VOCs depending on the relative proportions of each component (control mixture D) do not allow the use of trans-cinnamaldehyde in combination with a single other VOC to be considered as a solution to the technical problem.

[0126] On the other hand, mixture B according to the invention shows the best result, while the addition of trans-cinnamaldehyde to a similar mixture in proportions as described above also makes it possible to obtain a positive result, without substantially affecting the repulsion rate.

[0127] Example 2: Field treatment with mixture H

[0128] Tests were carried out in the field, in an uncontrolled atmosphere, with for formulations of mixture H (Linalool 1, Eugenol 3, Trans-cinnamaldehyde 4, Geraniol 1, Carophylene 1). An aphicidal treatment is carried out with a flo-nicamide formulation between the 4th and 6th leaf stages to eliminate the apterous insects.

[0129] The results are reported in Table 3 below, and represented in Figures 1 (winged) and 2 (wingless).

[0130] [Tables3] Stage Wingless Control Wingless Mix H Winged Control Winged Mix H 2 leaves 0.4 0.3 0.1 0.1 4 leaves 0.2 0.2 0.2 0.2 6 leaves 3.8 1.3 1.2 0.6 8 leaves 0.3 0.2 2.1 0.9

[0131] The results show the effectiveness of a mixture according to the invention for repelling aphids, whether winged or non-winged, under field cultivation conditions in an uncontrolled atmosphere. REFERENCES

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Claims

Claims

1. A mixture of volatile organic compounds (VOCs) which comprises at least linalool, eugenol and trans-cinnamaldehyde characterized in that the linalool / eugenol weight ratio ranges from about 1 / 4 to 2 / 3, and the trans-cinnamaldehyde / (linalool+eugenol) weight ratio ranges from about 2 / 7 to about 1 / 1.

2. VOC mixture according to claim 1, characterized in that the linalool / eugenol weight ratio is at least 3 / 8, more particularly approximately at least 2 / 5.

3. VOC mixture according to one of claims 1 or 2, characterized in that the weight ratio trans-cinnamaldehyde / (linalool+eugenol) is between approximately 1 / 3 and approximately 3 / 5, in particular between approximately 3 / 8 and approximately 5 / 9, more particularly between approximately 2 / 5 and approximately 1 / 2.

4. Mixture of VOCs according to one of claims 1 to 3, characterized in that it comprises: a. 5 to 40% of linalool b. 25 to 80% of eugenol c. 0 to 50% of trans-cinnamaldehyde the total a+b+c being less than or equal to 100% and the relative contents of each constituent being defined according to claims 1 to 3.

5. Mixture of VOCs according to one of claims 1 to 4, characterized in that it comprises: a. 15 to 35% of linalool b. 40 to 75% of eugenol c. 10 to 40% of trans-cinnamaldehyde the total a+b+c being less than or equal to 100% and the relative contents of each constituent being defined according to claims 1 to 3.

6. Repellent composition characterized in that it comprises the mixture of VOCs according to one of claims 1 to 5 and a support.

7. Repellent composition according to claim 6, characterized in that it is in solid form, in particular in the form of powder or granules.

8. Repellent composition according to claim 7, characterized in that it is in the form of powder with a particle size of 0.0001 to 0.5 mm. or in the form of granules with a particle size of 1 to 5 mm.

9. Repellent composition according to one of claims 6 to 8, characterized in that the content of the VOC mixture in the repellent composition is from about 0.1 to about 20% by weight, in particular from about 1 to about 10% by weight.

10. Use in agriculture of a mixture of VOCs according to one of claims 1 to 5 or of a repellent composition according to one of claims 6 to 9, to protect plants against damage caused by insect pests.

11. Use according to claim 10, characterized in that the insect pests are aphids, in particular of the genera in particular of the genus Myzus, more particularly of the species Myzus persicae.

12. Use according to one of claims 10 or 11, characterized in that the plants are chosen from Chenopodiaceae, in particular beets, more particularly sugar beets.

13. Use of a mixture of VOCs according to one of claims 1 to 5 or of a repellent composition according to one of claims 6 to 9, for repelling aphids, in particular of the genus Myzus, more particularly of the species Myzus persicae.

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