WO2023057083A1

WO2023057083A1 - Method for phytosanitary treatment using encapsulated cinnamic aldehyde

Info

Publication number: WO2023057083A1
Application number: PCT/EP2021/087856
Authority: WO
Inventors: Alberto Sardo
Original assignee: Xeda International
Priority date: 2021-10-04
Filing date: 2021-12-30
Publication date: 2023-04-13

Abstract

The present application relates to cyclodextrin-nanoencapsulated cinnamic aldehyde compositions, to the method for preparing same and to the use thereof for the phytosanitary treatment of plants, fruits and vegetables.

Description

DESCRIPTION

TITLE: METHOD FOR PHYTOSANITARY TREATMENT USING ENCAPSULATED CINNAMIC ALDEHYDE

The present invention relates to the field of phytosanitary and in particular insecticide treatments for plants, such as horticultural plants, in particular fruits or vegetables.

The chemical treatments of fruit or vegetables usually used present phytotoxicity with regard to the treated plants and are not without harm for the consumer. It is therefore particularly desirable to provide treatment methods using alternative active agents of natural origin.

The treatment must therefore be harmless for the treated plant, acceptable in terms of food, easy and economical to implement.

Cinnamic aldehyde is the main component (90%) of cinnamon oil and is found naturally in the trunk of Ceylon cinnamon, camphor and Chinese cinnamon (Casse).

It is used in many applications, in particular as a flavoring in food, in principle as an odorant in perfumery and even in agriculture: applied to the roots of plants, cinnamaldehyde has been shown to be an effective fungicide and to be used harmless in agricultural crops. It is also used as an insecticide and its smell repels animals such as cats and dogs.

However, the phytosanitary use of cinnamaldehyde is limited by the instability of the aldehyde and its very rapid degradation, and by the aggressiveness of the product on plants.

It is therefore desirable to provide new formulations of cinnamaldehyde, allowing an effective phytosanitary treatment.

The Applicant has now discovered that encapsulation of cinnamaldehyde makes it possible to increase the doses applied, while limiting phytotoxicity. Quite unexpectedly, the Applicant has also demonstrated an activity of encapsulated cinnamaldehyde on harmful species that are difficult to control to date, and does not show any harmfulness against beneficial insects. The encapsulated cinnamaldehyde according to the invention can therefore participate in the biocontrol of plants. According to a first object, the present invention relates to a phytosanitary treatment method comprising the application to the plants of a treatment composition, such that said treatment composition is an aqueous composition comprising encapsulated cinnamic aldehyde.

Cinnamic aldehyde, or cinnamaldehyde (more precisely trans-cinnamaldehyde) or 3-phenylpropenal is an organic compound of the phenylpropanoid family, with the formula CgH ₈ O and corresponding to the general formula:

The cinnamaldehyde present in the compositions may be present in pure form or in the form of a cinnamon extract containing, among other things, cinnamaldehyde.

By "phytotoxicity" is meant, according to the invention, any damage to fruits and vegetables, resulting from the direct action of the active ingredient (ie) cinnamaldehyde, illustrated by the modification of the visual appearance of said fruits and vegetables. or their leaves.

Preferably, according to the invention, "phytotoxicity" denotes the direct alteration by cinnamaldehyde of the integrity of the skin of said fruits and vegetables, in particular by modifying the color or the texture of their skin. More specifically, phytotoxicity can be illustrated by a homogeneous yellowish coloration, red pigmentation, the formation of yellow or brown spots or areas of necrosis, punctual or extensive, or even the formation of microlesions on the skin.

These microlesions then constitute a breeding ground for mold or the rotting of fruits and vegetables.

According to the invention, said phytotoxicity defined above results directly from the action of the active ingredient and consequently excludes natural aging phenomena, such as senescence in particular.

The following characteristics or each of their combinations represent preferred embodiments of the method according to the invention:

The phytosanitary process refers to the protective effect of cultivated plant species, against insects and harmful organisms and diseases, and/or more broadly to the improvement of yields. According to the invention, the phytosanitary treatment is illustrated in particular by a direct or indirect insecticidal, bactericidal or nematicidal activity, more particularly an insecticide treatment.

The phytosanitary treatment aims in particular at the eradication or prevention of attacks by harmful insects such as attacks by chewing insects such as the larvae of codling moths, Lepidoptera, and/or sucking perforating insects such as aphids, more particularly the attacks of black bean aphids (Aphis fabaé).

The phytosanitary treatment according to the invention is intended for all plants affected by these parasites, and in particular horticultural plants. Horticultural plants are understood to mean plants relating to market gardening, vegetable gardening, arboriculture and floriculture. These targeted plants are in particular cereals, fruits or vegetables such as corn, beets, sugar cane, cucurbits, tomatoes, courgettes, eggplants, broad beans, beans, salads, pome fruits, grapes, citrus fruits

According to an advantageous embodiment, the phytosanitary treatment has no harmful effect on beneficial insects. The term “beneficial insect” is understood to mean an insect that is a predator of harmful insects in particular. This term refers to ladybugs and bees in particular.

According to a more particular embodiment, the phytosanitary treatment according to the invention is indirect in that it attracts beneficial insects. Indeed, it has been demonstrated that the treatment according to the invention makes it possible to attract said beneficial insects which eradicate aphids. Thus, according to one embodiment, the treatment according to the invention has a double cumulative insecticidal effect by its direct and indirect action by the action of the beneficial insects which it attracts.

The encapsulated cinnamaldehyde according to the invention therefore makes it possible to participate in biocontrol.

By biocontrol, according to article L. 253-6 of the rural and maritime fishing code, we mean agents and products using natural mechanisms in the context of integrated pest management.

According to one embodiment, the method according to the invention comprises the prior step of diluting a concentrated aqueous composition of nanoencapsulated cinnamic aldehyde in water.

Typically, the concentrated aqueous composition contains 10 to 50% (weight/volume) of nanoencapsulated cinnamaldehyde in water. The expression “concentrated aqueous composition” refers to a composition of the “pre-mix” type intended to be diluted in water, prior to the application of the diluted composition thus obtained. Said concentrated composition is typically in the form of a concentrated aqueous suspension.

According to one embodiment, the cinnamic aldehyde is nanoencapsulated by a cyclodextrin.

The term “cyclodextrin” means any cyclic oligomer (oligosaccharide) composed of n glucopyranose CeH Os links linked at a-(1,4), hence the formula (CeH Osjn,

where n can typically be 6, 7 or 8.

Said cyclodextrins suitable for the invention can be chosen from non-functionalized (a, p, y) and functionalized (eg: hydroxypropylbetacyclodextrin, etc.) cyclodextrins.

The cyclodextrin nanoencapsulates the cinnamaldehyde in that the particles thus obtained have a nanometric size, that is to say less than 1000 nm in its largest dimension.

The cinnamic aldehyde can be encapsulated in combination with one or more essential oils such as, for example, clove oil, mint oil, thyme oil, oregano oil, palmarosa oil, eucalyptus oil and / or one of their constituents such as eugenol, L-carvone, thymol, carvacrol, geraniol, eucalyptol

According to another object, the present invention also relates to the composition comprising cinnamic aldehyde, optionally combined with one or more essential oils, encapsulated by a cyclodextrin, in dispersion in water.

Said composition comprises from 10 to 50% of nanocapsules (by weight/volume).

According to one embodiment, said concentrated aqueous composition further comprises one or more surfactant(s). Various surfactants or emulsifiers are known per se. According to the present invention, the term "emulsifier" means any type of agent usually used for this purpose, such as ethoxylated fatty alcohols, ethoxylated fatty acids, ethoxylated alkylphenols, sorbitan esters and their ethoxylated derivatives or any other product nonionic or anionic such as sodium tripolyphosphate, ethoxylated sodium lauryl sulfate.

Typically, said emulsifiable concentrated composition may comprise from 0 to 40% of surfactant(s).

According to another object, the present invention also relates to the process for preparing said concentrated aqueous composition, said process comprising:

The mixture of cinnamic aldehyde and possibly one or more essential oils, with a cyclodextrin,

Adding water to the mixture obtained.

Optionally, the process comprises the subsequent step of adding surfactants to the dispersion of nanocapsules obtained.

The concentrated aqueous composition can be diluted in a proportion of 1 to 10% (by volume) of concentrated aqueous composition of cinnamic aldehyde encapsulated in water, so as to obtain said treatment composition to be applied.

According to one embodiment, the concentrated aqueous composition comprises: from 10 to 50% (by weight/volume) of encapsulated cinnamic aldehyde, and from 50 to 90% (by weight/volume) of water.

The percentage of encapsulated cinnamic aldehyde refers to the total weight of the nanocapsules incorporating the cinnamaldehyde.

Typically, the nanocapsules comprise from 5 to 30% by weight of cinnamaldehyde, so that the concentrated aqueous composition comprises cinnamaldehyde at an amount of approximately 0.5-15% in weight/volume.

The treatment composition diluted by 1 to 10% in water for application therefore typically comprises from 0.1% to 5% of encapsulated cinnamaldehyde. Said treating composition can typically be applied by spraying, sprinkling or spreading, particularly by sprinkling.

Generally, said treating composition is applied to fields, in particular once or several times during the period between sowing and the maturing fruits or vegetables.

Said diluted composition can be applied at ambient temperature.

The quantity of treatment composition applied depends on the nature of the fruits or vegetables concerned and on the mode of application selected. It also depends on the amount of active ingredient to be applied.

Thus, the method according to the invention comprises the application of quantities of treating composition such that it allows the application of encapsulated cinnamic aldehyde at a dose of between 100 and 5000 ppm of pure cinnamic aldehyde.

It has been observed that nanoencapsulation increases the persistence of cinnamaldehyde on the plant. Thanks to this increased presence time, cinnamaldehyde can, in addition to its direct insecticidal activity, also induce an unexpected indirect insecticidal action, by attracting beneficial insects such as ladybugs for example. This effect of attracting beneficial insects is made possible thanks to the longer persistence of cinnamaldehyde on the plant due to its encapsulation by cyclodextrin.

Unless otherwise indicated, the percentages indicated above are given by weight relative to the total volume of the treatment composition.

tricks

[Fig 1] Figure 1 illustrates the percentage of sugar beets infected with Aphis fabae after a single treatment at To of the compositions according to the invention (at five different concentrations), as well as for the control and the reference treatment (alternating indoxacarb and pyrethroids).

[Fig 2] Figure 2 illustrates the results obtained for the reproduction of a second experiment. The following examples are given by way of non-limiting illustration of the present invention.

EXAMPLE

Preparation of the concentrated composition:

For 100g of product:

30.5g of betacyclodextrin and 3.5g of cinnamaldehyde are added to 66g of water at room temperature, with stirring, and the solution is stirred for 24 hours. The concentrated composition has a density of 1.131 g/ml, and contains 39.7 g/L of cinnamaldehyde.

Preparation of the treatment solution:

Samples of the concentrated preparation are added to the water. The treatment solution thus prepared is mixed and applied to the field.

For example, the first dilution was prepared by mixing 3,520L of concentrated composition with water in a sprayer with 400L of water.

The 3.520L of concentrated composition added to the sprayer therefore contain 140g of cinnamaldehyde for 400L of water, i.e. 0.035%=350ppm (test 2).

Activity

The efficacy and selectivity of the composition prepared above were studied at five concentrations on aphis fabae and other aphids, on sugar beets: [Table 1]

For each trial, the first application was made after the appearance of aphids. Five applications were made during the beet growth cycle, generally 7 to 10 days apart.

Applications were made by spraying.

The experiment is reproduced a second time: The activity is observed in a preliminary way after the application of the first dose (single dose). The results are illustrated in Figures 1 and 2:

From the first application, the attack is immediately inhibited for all the compositions according to the invention, at all the concentrations, unlike the reference treatment using synthetic agents.

No phytotoxicity phenomenon appeared. A decrease in aphid attack is observed from D+7, including for the control (UTC) and the reference treatment.

This is due to an arrival of ladybugs on D+7 on the treated rows. The ladybirds then moved into the rows of control and reference treatment, in the immediate vicinity of the test plot.

The treatment according to the invention therefore also has an attracting effect on ladybugs and, in fact, allows an indirect treatment of aphids. This effect of attracting beneficial insects could have taken place thanks to the long persistence of cinnamaldehyde on the plant due to its encapsulation by cyclodextrin. Without this encapsulation, the cinnamaldehyde would have volatilized too quickly and would not have had enough time on the plant to attract ladybugs.

Claims

9 CLAIMS

1. Phytosanitary treatment process comprising the application to the plants of a treatment composition, such that said treatment composition is an aqueous composition comprising encapsulated cinnamic aldehyde.

2. Method according to claim 1 such that it comprises the preliminary step of diluting a concentrated aqueous composition of cinnamic aldehyde encapsulated in water.

3. Method according to claim 2 such that the dilution is carried out at a rate of 1 to 10% (by volume) of concentrated aqueous composition of cinnamic aldehyde encapsulated in water.

4. Process according to claim 2, such that the concentrated aqueous composition comprises: from 10 to 50% (by weight/volume) of encapsulated cinnamic aldehyde, and from 50 to 90% (by weight/volume) of water.

5. Method according to any one of the preceding claims, such that the cinnamic aldehyde is encapsulated in combination with one or more essential oils.

6. Method according to any one of the preceding claims, such that the cinnamic aldehyde is nanoencapsulated by a cyclodextrin.

7. Method according to any one of the preceding claims, such that the said composition comprises an encapsulated cinnamon extract.

8. Method according to any one of the preceding claims, comprising the application of encapsulated cinnamic aldehyde at a dose of between 100 and 5000 ppm of pure cinnamic aldehyde.

9. Method according to any one of the preceding claims, such as an insecticide treatment.

10. Method according to any one of the preceding claims, such that it is an indirect insecticide treatment in that it attracts beneficial insects.

11. Method according to any one of the preceding claims, such that the nanoencapsulation of cinnamaldehyde increases the duration of persistence of cinnamaldehyde on the plant, thus making it possible to attract beneficial insects.

12. Method according to any one of the preceding claims, such that the application is carried out by sprinkling, in the field.

13. Method according to any one of the preceding claims, such that the treatment aims to eradicate or prevent attacks by chewing insects such as the larvae of codling moths, Lepidoptera, and/or sucking perforating insects such as aphids.

14. Method according to any one of the preceding claims aimed at eradicating or preventing attacks by black bean aphids (Aphis fabae).

15. Composition comprising cinnamic aldehyde, optionally combined with one or more essential oils, encapsulated by a cyclodextrin, in dispersion in water.

16. Process for preparing the composition according to claim 15 comprising:

The mixture of cinnamic aldehyde and one or more essential oils, with a cyclodextrin,

Adding water to the mixture obtained.