WO2022200278A1

WO2022200278A1 - Method for preventive treatment of a plant

Info

Publication number: WO2022200278A1
Application number: PCT/EP2022/057361
Authority: WO
Inventors: Jérémy DAUFFY; Pauline HENRY; Laurent Martel
Original assignee: Evergreen Garden Care France Sas
Priority date: 2021-03-22
Filing date: 2022-03-21
Publication date: 2022-09-29
Also published as: EP4312546A1; FR3120769A1; FR3120769B1

Abstract

The present invention relates to a method for preventive treatment of a plant to prevent infestation by a parasite, consisting in applying to said plant a plant oil or a composition containing said plant oil so as to form a physical barrier against the parasite, before occurrence of the infestation.

Description

METHOD FOR PREVENTIVE TREATMENT OF A PLANT

TECHNICAL FIELD OF THE INVENTION The present invention relates to a process for the preventive treatment of a plant to protect a plant for an entire season from infestation by a parasite, such as a mite, an insect or a pathogen for example.

STATE OF THE ART In the fields of horticulture and agriculture, insecticides and fungicides, generally referred to as pesticides, are very widely used to treat plants against insects and diseases which degrade plants. and reduce crop yield.

Pesticides are typically foliar, i.e. they are applied to the leaves and absorbed by them.

The use of alternative solutions, showing effectiveness in the fight against insects and diseases, are interesting because they make it possible to reduce the use of pesticides, or at least the number of applications of these pesticides, but remain to this day almost non-existent. Professionals use technical data available to them

(Plant health report, Fredon alerts) in order to apply plant protection products at the right time. Conversely, the amateur gardener only treats when the infestation is visible, which limits the effectiveness of curative products because the problem is then well established and the plant has already been degraded by parasites (insects, mites or fungi). ), sometimes irreversibly.

In addition, the cultivation of plants generally requires the use of fertilizers that stimulate their growth. Fertilizers are root-based, that is, they are applied to the soil and absorbed by the roots, or foliar.

Unlike pesticides, fertilizers are applied early in plant growth, and therefore at generally different times than pesticides.

This leads to applying pesticides and fertilizers separately, which can be a source of physical stress in addition to being very time-consuming.

DESCRIPTION OF THE INVENTION An object of the invention is to propose a process for treating a plant which makes it possible to overcome the drawbacks described above.

The invention is particularly aimed at providing a process for treating a plant making it possible to prevent the latter from being degraded by parasites (insects, mites or fungi in particular). To this end, the invention proposes a process for the preventive treatment of a plant to prevent infestation by a parasite, consisting in applying to said plant a vegetable oil or a composition containing said vegetable oil so as to form a physical barrier against against the parasite, before the infestation appears.

Vegetable oil is therefore used as a preventive pest control agent. By “parasite” is meant any animal species likely to be harmful to the development of the plant, which usually degrades its structure, in particular but not exclusively insects (the composition is then an insecticide). Examples of pests, often referred to as "pests", include aphids, scale insects, thrips whiteflies. The term "parasite" also includes mites (also called spider mites) which can infest plants in a similar way, as well as fungi, the latter developing on the plant, such as black spot disease of roses. The treatment method according to the invention is very particularly suitable for preventive treatment of the plant against fungi. A "vegetable oil" is a fatty phase obtained by cold pressing extraction from an oleaginous plant, that is to say a plant whose seeds, nuts, almonds or fruits contain lipids. A vegetable oil is mainly composed of chains of fatty acids with a linear structure. Essential oils and hydrolats are not vegetable oils and do not form part of the invention. They are obtained by hydrodistillation, condensation, then separation of the oily phase and the aqueous phase. The oily phase is the essential oil and the aqueous phase is the hydrosol.

The treatment is carried out preventively, in that the vegetable oil, optionally in the form of a chemical composition comprising other constituents, is applied before the appearance of the infestation, that is to say before the appearance of parasites on the plant or of their symptoms (first individuals for insects or mites, first colored spots for fungi for example). Contrary to a curative application, any prolonged contact between the parasites and the plant is avoided, which avoids the degradation of the plant usually caused by the latter.

In other words, the invention also relates to the use of a vegetable oil for preventive treatment of a plant against infestation by a parasite, by application of the vegetable oil to the plant before the appearance of the pest. infestation.

However, vegetable oil can be applied to the plant after the infestation has appeared, when the parasites or fungi are already present on the plant. The vegetable oil will then have a curative effect on the parasites already present, as well as a preventive effect which limits the development of the infestation, or at least prevents the appearance of a new infestation, and therefore the appearance of new ones. parasites or fungi on the plant. In the remainder of this text, reference will be made to a "composition" to designate, unless otherwise indicated, the oil alone, that is to say a composition consisting of oil, or a composition comprising oil and other constituents. The invention thus relates to the use of a vegetable oil for the preventive treatment of a plant, in which the vegetable oil is applied in the form of a composition consisting of vegetable oil or comprising vegetable and other constituents such as those described below.

The composition is preferably applied foliarly, that is to say it is applied directly to the aerial parts of the plant, in particular the foliage, the stems and/or the flower buds. It can be applied for example using a pressure sprayer, or a ready-to-use spray type device, etc.

The composition is intended for the treatment of any type of plant, and in particular ornamental plants, and vegetable and fruit crops.

By way of example, the composition is particularly suitable for the treatment of roses, spirea, impatiens, viburnum, or even asters. With regard to vegetable and fruit crops, mention may be made, respectively, of zucchini and apple trees.

The composition is preferably applied during the vegetative period of the plant. The vegetative period, also known as the growing season, corresponds to the part of the calendar year during which the local weather conditions (i.e. precipitation and temperature) allow normal growth of the plant. The vegetative period obviously depends on the nature of the plant in question.

Vegetable oil has a barrier effect, in the sense that it acts physically by forming a barrier between the plant and the parasite (preventive effect) or on the parasite by covering it and suffocating it (curative action). It does not have an insecticidal, acaricidal, or chemical fungicidal (chemical action) effect.

The vegetable oil is preferably chosen from castor oil, soybean oil, or a mixture thereof. These oils have the advantage of being readily available commercially. and low cost. In addition, these oils have little or no phytotoxic effect when used on the plant, an effect sometimes being observed with certain oily compositions.

Preferably, the composition does not include rapeseed oil, sunflower oil or paraffin oil. These oils are indeed recognized from a regulatory point of view as phytopharmaceutical active ingredients, and require approval to be used in the fields of agriculture and horticulture.

With regard to parasites, the composition is particularly effective in protecting against rust disease (Phragmidium mucronatum), black spot disease (Diplocarpon rosae or Marssonina rosae), powdery mildew (Erysiphe sp.), or else boxwood diseases ( Cylindrocladium buxicola, Volutella buxi ), and to control populations of aphids (for example Macrosiphum rosae), mealybugs, mites, thrips, or even whiteflies.

Preferably, at least one nutrient is applied with the vegetable oil. In other words, the composition further comprises at least one nutrient. In general, the home gardener is used to regularly applying fertilizer or adding nutrients to his plants at the start of the season.

The amateur gardener applies the treatment products when the infestation is well established, due to a lack of technical information.

Therefore, the combination of a nutrient and a vegetable oil, for the implementation of the preventive treatment according to the invention, has the advantage that the composition is applied upstream of the infestation in accordance with the usual of the gardener regarding the fertilizer described above.

The nutrient provides some of the nutrients necessary for the development of the plant, and improves the yield and quality of crops. Thus, the vegetable is supplemented by the nutritive element, and treated preventively against the parasites by the vegetable oil. A growth effect of the plant is therefore associated with an effect of preventive protection of the plant against parasites. These two effects are obtained by applying a single composition, instead of applying a pesticide and applying a fertilizer separately, thus reducing the physical constraints in addition to reducing the time required. in carrying out these tasks.

The presence of a nutrient fits perfectly with the preventive nature of the process and the regular application over time of the composition, since, generally in agriculture and horticulture, the nutrient is applied from the start of the growth of the plant and the application is renewed regularly. The user can therefore use the composition of the invention as if he were using a fertilizer, while also benefiting from the protective effect of the vegetable oil.

The nutrient preferably comprises at least one mineral fertilizer. It is more preferably a nitrogen-based fertilizer which has the advantage of being effective and stable. Preferably, the composition comprises the following oil/nutrient couples, which all lead to an effective treatment, without phytotoxicity: Castor oil/nitrogen and soybean oil/nitrogen.

Preferably, the vegetable oil/nutrient element mass ratio is between 1:1 and 100:1, preferably between 5:1 and 12:1 for a mineral nutrient element, or between 30:1 and 40:1 for a mineral element. organic nutrient. These ratios make it possible to obtain a satisfactory growth stimulation effect while ensuring good coverage of the aerial parts of the plant and therefore optimal treatment.

The nutrient may include one or more major nutrients and/or one or more minor nutrients. Major nutrients are well known as such to those skilled in the art. These are the nutrients that the plant needs in large quantities. Can be present in the composition for example nitrogen, phosphorus, and / or potassium, nitrogen being preferred. Minor nutrients are also well known as such to those skilled in the art. These are the nutrients that the plant needs in smaller quantities relative to the major nutrients. May be present in the composition, for example, iron (Fe), manganese (Mn), copper (Cu), zinc (Zn), calcium (Ca) and/or molybdenum (Mo).

If necessary, you can refer to the website: https://espacepourlavie.ca/besoins-nutritives-des-plantes, which defines and lists all the major and minor nutrients. These nutrients are found especially in fertilizers, where the nitrogen, phosphorus and potassium (NPK) contents are always indicated. Surprisingly, no antagonistic effect is observed between the nutritive element and the vegetable oil, even though the first promotes the growth of the plant and therefore the appearance of young shoots which attract the parasites, while the second fight against them. The composition allows the plant to develop while effectively preventing the appearance and proliferation of parasites. In addition, the composition is not phytotoxic, so the leaves are not burned. There is no aggravating effect of the nutrient, on the burning effect sometimes observed when bringing certain vegetable oils into contact with certain species of plants.

According to a preferred embodiment, calcium nitrate is applied with the vegetable oil. In other words, the composition includes calcium nitrate. Calcium is a minor nutrient which stiffens the cell walls of plant cells when the composition is applied. In doing so, it makes the plant more resistant to external aggressions, and avoids any deficiency of the plant in calcium which is an essential element for its growth. Calcium nitrate plays a role both in the growth of the plant (calcium useful for the development of the plant) and in the antiparasitic effect (reinforcement of the cell wall).

The calcium nitrate may be present in the composition with one or more nutrients as described previously, or without the latter. Surprisingly, no antagonistic effect is observed between the nutrient and calcium nitrate, even though the first promotes the growth of the plant, while the second stiffens the cells and would therefore tend to reduce growth. of the vegetable. No growth retardation (growth dwarfism) was observed on the plants treated with the composition of the invention, which indicates that, contrary to what a person skilled in the art could have supposed, the use of nitrate of calcium in the composition does not reduce plant growth.

Preferably, the calcium nitrate/vegetable oil mass ratio in the composition is between 1:35 and 1:70, preferably between 1:55 and 1:59. These ratios make it possible to obtain an effect of resistance to external attack. satisfactory while ensuring good coverage of the foliage of the plant. According to a preferred embodiment, the composition comprises:

- from 0.5% to 3% by weight, preferably from 1.5% to 1.9% by weight, of vegetable oil,

- from 0.01% to 1% by weight, preferably from 0.03% to 0.5% by weight, more preferably from 0.15% to 0.3% by weight, of nutrient,

- from 90% to 99.4% by weight, preferably from 96% to 98% by weight, of water. The composition optionally comprises co-formulants to improve the application, the preservation or the stability of the formula, in particular surfactants and preservatives and stabilizers for example.

According to a preferred embodiment, the composition is obtained by dilution in water of a concentrate comprising: - from 20% to 90% by weight, preferably from 50% to 70% by weight, of vegetable oil,

- from 0.1% to 10% by weight, preferably from 1.5% to 5% by weight, of nutritive element.

The rest of the composition comprises water and, preferably, the co-formulants before applying it to the vegetation to be treated. The concentrate is previously stored and preserved. It is diluted by the user with water just before treating the vegetation, in order to obtain the composition ready to be applied to the vegetation.

Alternatively, the composition may be in a “ready to use” formulation, or “Ready To Use” in English (acronym RTU). The dilution of the concentrate comprising the vegetable oil and the nutritive element is carried out upstream of the treatment, so that the user only has to treat the vegetation without the need to carry out the mixture: the product that puts in work the user does not require any dilution prior to its use. In practice, the composition is directly prepared and stored in a container suitable for this purpose for a determined time, for example a container intended for sale. When he wishes to treat vegetation, the user can therefore directly use the RTU mixture.

Preferably, the concentrate is present in the composition in an amount between 1 mL and 300 mL, preferably between 10 mL and 100 mL, and more preferably between 20 mL and 50 mL, per liter of composition, the complement to 1 liter being water. The composition of course refers to the final composition resulting from the dilution of the concentrate with water.

As regards the treatment methods, the composition is preferably applied at least one month before the expected appearance of the infestation, and at a rate of between every day and every 21 days, preferably between every 7 days and 18 days, more preferably between every 10 days and 16 days, and even more preferably between every 13 days and 15 days. Such a rate makes it possible to obtain a preventive effect with regard to satisfactory parasites and/or fungi, and, when the composition comprises a nutritive element, this rate ensures in parallel a regular supply and sufficiently spaced out in time of the nutrient to optimally promote plant growth.

Furthermore, the composition is preferably applied at a rate of 100 L/ha (Liters per hectare) to 3000 L/ha, preferably from 300 L/ha to 2000 L/ha, more preferably from 600 L/ha to 1500 L/ha, and even more preferably from 800 L/ha to 1200 L/ha.

The invention also relates to a composition for implementing the process for the preventive treatment of a plant as described above.

The composition comprises: a vegetable oil, a nutrient, preferably comprising an inorganic fertilizer, in which the vegetable oil/nutrient mass ratio is between 1:1 and 100:1, preferably between 5:1 and 12:1 for an inorganic nutrient, or between 30:1 and 40:1 for an organic nutrient.

DESCRIPTION OF FIGURES

Other advantages and characteristics of the invention will appear on reading the following description given by way of illustrative and non-limiting example, with reference to the following appended figures:

Figure 1 is a graph that represents the efficacy over time of different antiparasitic compositions for the treatment of black spot disease;

Figure 2 is a graph that represents the effectiveness over time of different antiparasitic compositions for the treatment of rust;

Figure 3 is a graph which represents the effectiveness over time of different antiparasitic compositions against mealybugs;

Figure 4 is a graph that represents the efficacy over time of different antiparasitic compositions for the treatment of powdery mildew on barberry; Figure 5 is a graph that represents the effectiveness over time of different antiparasitic compositions for the treatment of black spot on roses;

Figure 6 is a bar graph which represents the effectiveness over time of different antiparasitic compositions for the treatment of rust on roses; FIG. 7 is a graph which represents the effectiveness over time of various antiparasitic compositions for the treatment of roses against aphids;

Figure 8 is a bar graph that represents the efficacy over time of different antiparasitic compositions against defoliation of roses caused by black spot disease.

EXAMPLES OF REALIZATION OF THE INVENTION

Example 1 Several compositions were prepared and then applied to different species of plants, to treat them against black spot disease, rust, and scale insects.

To do this, the concentrates numbered C1 to C4 in the following table 1 are first prepared, each comprising at least one vegetable oil. Each of these concentrates is mixed with an aqueous phase in order to obtain the respective compositions. To facilitate understanding, the terms C1 to C4 are also used to speak of the compositions applied to the plant.

To prepare the compositions, 30 mL of concentrate is diluted in 970 mL of water.

The compositions are applied to the level of the leaves of the plant, on the top and on the underside of the leaves, up to the point of run-off, namely until the moment when any additional application of product drips from the leaves and falls to the ground.

The compositions are applied every two weeks, from the beginning of the season (March) until the end of the season (September).

The effectiveness of these compositions is compared with untreated vegetation (test N) and with several commercial insecticide/fungicide products: Rozen-Pilzfrei Saprol® (black spot and rust / 9.72g/L triticonazole / noted RPS in the figures) marketed in particular by the company Evergreen Garden Care GmbH, Rapidinsect® (cochineals / rapeseed oil 700g/L and pyrethrum 7g/L / noted RI in the figures) marketed in particular by the company Evergreen Garden Care France SAS, and Naturen Eradibug® (cochineals / Rapeseed oil 777g/L / noted NE in the figures) marketed in particular by the company Evergreen Garden Care France SAS. The untreated plants are denoted N in the figures.

Table 1 indicates the nature of the constituents of the various concentrates (C1 to C4), as well as the quantity of these constituents applied per hectare once the concentrate has been diluted at a rate of 30 mL/L to give the corresponding composition. (C1 to C4).

In FIGS. 1 and 2, the intensity (“Intensity” in English) of the black spot disease and the intensity of the rust are indicated on the ordinate, and denoted Int (%), as a function of time on the abscissa. In FIG. 3, the ordinate AP (“Average Population”) corresponds to the average population of mealybugs per plant, as a function of the days, denoted D (“Days”), on the abscissa.

Table 1 On the graphs of FIGS. 1 and 2, it is observed that compositions C1 to C4, used as a preventive measure (before the appearance of the disease), strongly limit the development of black spot and rust over time, in addition to delay their onset. The effectiveness of compositions C1 to C4 is comparable to that of Rozen-Pilzfrei Saprol® for black spot, and greater than that of Rozen-Pilzfrei Saprol® for rust.

In the graph of FIG. 3, it is observed that the compositions C1 to C4, used curatively (when the disease is already present), eliminate mealybugs effectively, thus treating the plant. The effectiveness of compositions C1 to C4 against scale insects is comparable to that of Rapidinsect® and Naturen Eradibug®. These examples thus confirm that the treatment method according to the invention aims to treat a plant preventively, and also makes it possible to treat the plant curatively, that is to say to treat a disease already present.

Therefore, the application of a composition according to the invention makes it possible to prevent, limit, and delay a disease to come, while treating a disease possibly already present during the application.

Example 2

Several experimental tests were carried out in order to evaluate the impact of each of the constituents of the composition on its preventive effect.

The following compositions were thus prepared: a composition P4, which corresponds to the concentrate C1, a composition P1, which corresponds to the concentrate C1 in which the urea and the calcium nitrate have been replaced by water; this composition therefore makes it possible to test the effect of castor oil (vegetable oil) in the composition, a composition P2, which corresponds to the concentrate C1 in which the castor oil and the calcium nitrate have been replaced by 'water ; this composition therefore makes it possible to test the effect of the urea in the composition, a composition P3, which corresponds to the concentrate C1 in which the castor oil and the urea have been replaced by water; this composition therefore makes it possible to test the effect of the calcium nitrate in the composition.

The compositions P1, P2, P3, and P4 are applied to the plants in foliar form before the appearance of the disease, and the evolution of this disease is monitored over time. The plants were chosen for their susceptibility to disease, so as to be certain that the disease appears.

Example N corresponds to no treatment (control).

The graph in figure 4 represents the evolution of the intensity (Int%) of powdery mildew on barberry as a function of time. The compositions are applied every 13 to 14 days, each application being illustrated by the vertical lines A, B, C and D. The amount of each composition applied is 1000 L/hectare, and the volume concentration of concentrate relative to the volume total of diluted composition is 30 mL/L.

Similarly, the graph in figure 5 represents the evolution of the intensity (Int %) of the black spot on roses as a function of time. The compositions are applied every 11 to 15 days, each application being illustrated by the vertical lines A, B, C, D, F and H. The amount of each composition applied is 1000 L/hectare, and the volume concentration of concentrate relative to the total volume of diluted composition is 30 mL/L.

On these two graphs, it can be seen that the curves of composition P1 (castor oil) and composition P4 are almost superimposable and lead at the end of treatment to a greatly reduced intensity of powdery mildew and black spot compared to the untreated plants N. On the contrary, the intensity is little impacted by urea P2 and calcium nitrate P3.

This means that the preventive antiparasitic effectiveness of the composition comes from castor oil, i.e. vegetable oil. The graph in figure 6 illustrates similar results obtained by preventive treatment of roses against rust. The intensity of the rust (Int %) is represented on the ordinate, and the various compositions P1 to P4 as well as the control N are represented on the abscissa. The intensity of the rust is represented at different points in time, denoted a, b, and c, spaced two to three weeks apart.

It is observed that urea P2 and calcium nitrate P3 lead to a regular increase in the intensity of rust over time. On the contrary, castor oil P1 and composition P4 lead to a strong slowing down and a marked decrease in the intensity of rust. These results again demonstrate the preventive antiparasitic effect of the vegetable oil in the composition.

The graph in figure 7 illustrates the results relating to the treatment of roses against aphids. The ordinate shows the average number of aphids per treated region of the rosebush, denoted Np, as a function of time on the abscissa (number of days D). It is noted that the evolution of the number of aphids by treatment with urea P2 and calcium nitrate P3 is similar to that of the control N, namely an increase with a peak on the ^10th day followed by a decrease until ^28th day.

On the contrary, the treatments with castor oil P1 and composition P4 lead to an almost immediate stabilization of the number of aphids, followed by a regular reduction until the ^28th day.

Consequently, the vegetable oil, and consequently the composition which contains it, not only makes it possible to delay the development of the number of aphids, and more generally of the disease, but also to reduce its intensity. Indeed, the maximum number of aphids for the control is approximately 115 on the ^10th day, against only 40 from the ^1st day of treatment. The treatment is therefore quick and effective.

In connection with the fact that the number of aphids on the ^1st day of treatment is 40, and not zero, this example demonstrates both the preventive and curative effectiveness of the vegetable oil and of the composition. Indeed, the initial aphid population does not stagnate, but decreases, and this from the start of the treatment.

Example 3

Other trials were carried out to assess the impact of the composition on the defoliation of roses caused by black spot disease.

The defoliation (Df%) is represented on the ordinate, and the P4 composition at different stages of disease development, as well as the control N, are represented on the abscissa.

P4 (A-J) was applied preventively every two weeks. Each application has its own associated letter (the first application is called A, the second 15 days later is called B, etc.). These applications are similar to the vertical bars A to H illustrated in Figures 4 and 5. In the case of compositions P4 (KMO) and P4 (KLMNOP), the same composition was applied this time as a curative (on the appearance of symptoms), either over a period of 2 weeks (P4 (KMO)), or every week (P4 (KLMNOP)).

Table 2 below shows the day of the different applications.

On the graph, the bars d, e, f, and g represent specific measurement instants:

- d: the measurement was taken 13 days after application F,

- e: the measurement was taken 4 days after application H,

- f: the measurement was taken 5 days after application I,

- g: the measurement was carried out 12 days after application J.

Table 2

In the case of the control, the defoliation increases regularly, and reaches 80% at the end of the treatment.

In comparison, the treatment of the black spot by the composition leads to a maximum defoliation of 38%.

Consequently, the preventive application of the composition makes it possible to control and reduce the intensity of the black spot.

Claims

1. Process for the preventive treatment of a plant to prevent infestation by a parasite, consisting in applying to said plant a vegetable oil or a composition containing said vegetable oil so as to form a physical barrier against the parasite, before appearance of the infestation.

2. The method of claim 1, wherein the pests include aphids, mealybugs, whiteflies, spider mites, thrips, fungi responsible for black spot disease, rust, powdery mildew or boxwood disease.

3. A method according to claim 1 or claim 2, wherein the vegetable oil or composition is applied during the vegetative period of the plant.

4. Method according to any one of the preceding claims, in which the application is foliar, that is to say directly on an aerial part of the plant.

5. Method according to any one of the preceding claims, in which the vegetable oil is chosen from castor oil, soybean oil, or a mixture thereof.

6. Method according to any one of the preceding claims, in which at least one nutrient element is additionally applied with the vegetable oil.

7. A method according to claim 6, wherein the nutrient comprises a major nutrient, preferably nitrogen.

8. Process according to claim 6 or claim 7, in which the vegetable oil / nutrient mass ratio is between 1: 1 and 100: 1, preferably between 5: 1 and 12: 1 for a mineral nutrient, or between 30:1 and 40:1 for an organic nutrient.

9. A method according to any of claims 6 to 8, wherein the nutrient comprises a minor nutrient, preferably calcium.

10. Process according to any one of the preceding claims, in which calcium nitrate is also applied with the vegetable oil.

11. Process according to claim 10, in which the mass ratio of calcium nitrate/vegetable oil is between 1:35 and 1:70, preferably between 1:55 and 1:59.

12. Method according to any one of claims 6 to 11, in which the vegetable oil is applied to the said vegetable in the form of a composition which comprises:

- from 90% to 99.4% by weight, preferably from 96% to 98% by weight, of water.

13. Method according to any one of claims 6 to 12, in which the vegetable oil is applied to the said vegetable in the form of a composition obtained by dilution in water of a concentrate comprising:

- from 20% to 90% by weight, preferably from 50% to 70% by weight, of vegetable oil, - from 0.1% to 10% by weight, preferably from 1.5% to 5% by weight , nutrient.

14. Process according to claim 13, in which the concentrate is present in the composition in an amount comprised between 1 ml_ and 300 ml_, preferably between 10 ml_ and 100 ml_, and more preferably between 20 ml_ and 50 ml_, per liter of composition, the complement to 1 liter consisting of water.

15. Method according to any one of the preceding claims, in which the vegetable oil or the composition is applied at least one month before the appearance of the infestation, and at a rate of between every day and every 21 days. , preferably between every 7 days and 18 days, more preferably between every 10 days and 16 days, and even more preferably between every 13 days and 15 days.

16. Method according to any one of the preceding claims, in which the vegetable oil or the composition is applied at a rate of 100 L/ha to 3000 L/ha, preferably of 300 L/ha to 2000 L/ha, of more preferably from 600 L/ha to 1500 L/ha, and even more preferably from 800 L/ha to 1200 L/ha.

17. Use of a vegetable oil to treat a plant as a preventive against infestation by a parasite, by applying the vegetable oil to the plant before the appearance of the infestation.