Method for the treatment and control of post-harvest diseases in fruits and vegetables and compositions comprising natural extracts and plant-strengthening and/or fungicidal formulations for use in said method

Abstract

The present invention relates to a method for the control and the treatment of post-harvest diseases in fruits and vegetables by means of simultaneous and combined application of (i) a first formulation, which is aqueous or in the form of an emulsifiable concentrate, which comprises a plant extract and is applied in the form of an aqueous solution and (ii) a second formulation, in the form of an emulsifiable concentrate, soluble liquid or concentrated suspension, which is applied as an aqueous solution, selected from amongst: a plant-strengthening formulation that contains at least one phosphite salt; a fungicidal formulation that contains at least one synthetic fungicide of the phosphonate family, preferably ethyl phosphonic acid salts; or a combination thereof. Each formulation may be a different composition or form part of a single composition. A further subject matter of the present invention is therefore said composition for post-harvest protection of fruits and vegetables which is constituted by the combination of the aforementioned components.

Claims

1. A method for the treatment and control of post-harvest diseases in fruits and/or vegetables which comprises applying in a simultaneous and combined manner on the fruits and/or vegetables: a. a first formulation in the form of an emulsifiable concentrate which has the following elements in parts by volume of the total of the formulation: (i) Cinnamaldehyde: 0.8-40% p/v (ii) Polysorbate 80: 5-20% p/v (iii) Triblock copolymer of formula
HO(CH.sub.2CH.sub.2O).sub.20(CH.sub.2CH(CH.sub.3)O).sub.70(CH.sub.2CH.sub.2O).sub.20H and which has a molecular weight of approximately 5,800 Da: 5-20% p/v (iv) Polyethylene glycol 400 dioleate: 10-50% p/v (v) Solvent: qs and which is applied in a water solution at a non-phytotoxic concentration of the cinnamaldehyde of between 500 ppm and 1,500 ppm; and b. a second formulation in the form of an emulsifiable concentrate, soluble liquid or concentrated suspension and which is applied as an aqueous solution, which is: (i) a fungicidal formulation which contains phosethyl al as synthetic fungicide; or (ii) a combination of said fungicidal formulation with a plant strengthening formulation which contains at least one phosphite salt; by means of one of the forms selected from the group consisting of drencher, bath and spray.

2. The method according to claim 1, wherein the formulations are applied once on the fruit and/or vegetable following the harvesting thereof, within 48 hours of the harvesting, with an application time of the formulations of between 30 seconds and 1 minute inclusive.

3. The method according to claim 1, wherein the phosphite salt contained in the plant-strengthening formulation is selected from the group consisting of potassium phosphite, calcium phosphite, sodium phosphite and any combination thereof.

4. The method according to a claim 1, wherein the plant-strengthening formulation has the following composition: Phosphite salts: 10-60% Non-ionic surfactant: 0-10% PH regulator: 0-10% Water: qs.

5. The method according to claim 1, wherein the fungicidal formulation is the following in parts by volume of the total of the fungicidal formulation: Phosethyl al: 20-50% Ionic surfactant: 0-10% Non-ionic surfactant: 0-10% Dispersant: 0-10% Thickeners: 0-10% Solvent: qs.

6. A composition for carrying out the treatment and control method for post-harvest diseases in fruits and/or vegetables described in claim 1, which comprises: a. a first formulation in the form of an emulsifiable concentrate which has the following elements in parts by volume of the total of the formulation: (i) Cinnamaldehyde: 0.8-40% p/v ii Polysorbate 80: 5-20% p/v (iii) Triblock copolymer of formula
HO(CH.sub.2CH.sub.2O).sub.20(CH.sub.2CH(CH.sub.3)O).sub.70(CH.sub.2CH.sub.2O).sub.20H and which has a molecular weight of approximately 5,800 Da: 5-20% p/v (iv) Polyethylene glycol 400 dioleate: 10-50% p/v (v) Solvent: qs; and b. a second formulation in the form of an emulsifiable concentrate, soluble liquid or concentrated suspension, which is: (i) a fungicidal formulation which contains phosethyl al as synthetic fungicide; or (ii) a combination of said fungicidal formulation with a plant strengthening formulation which contains at least one phosphite salt.

Description

BRIEF DESCRIPTION OF THE FIGURES

(1) FIG. 1: Photographs which show the existence of severe toxicity produced in the fruit to be applied a composition based only on cinnamaldehyde according to Example 1.

(2) FIG. 2: Photographs which show the phytotoxicity produced in the fruit to be applied a composition based on cinnamaldehyde as plant extract combined with synthetic fungicides according to Example 2.

EXAMPLES

(3) With the aim of providing a better understanding of the invention and according to a practical embodiment of the same, a series of examples accompany this description as an integral part thereof, wherein, in an illustrative and non-limiting character of the invention, the result obtained when applying the following to post-harvest fruits is compared: a post-harvest treatment composition based only on plant extract (Example 1), a composition based on plant extract with conventional synthetic fungicides in normal usage doses (commercial) (Example 2) and compositions according to the present invention (Examples 3 and 4).

(4) Thus, for the selection of the combination of synergetic treatments of plant-strengtheners based on phosphite salts or fungicides of the phosphonate family, specifically ethyl phosphonic acid salts, the efficacy, separately and combined, was studied, as well as the selectivity (presence/absence of phytotoxicity) of the natural extracts, which, given the chemical structure thereof and the predominant chemical group thereof (aldehydes, phenols, terpenes . . . ) has a significant fungicidal capacity, such as extracts of clove, cinnamon, citrus and other vegetables and plants. In all the cases, as has been demonstrated, the fungicidal capacity of the plant extract was cancelled by the aggressive phytotoxic character of the extract itself. Thus, it is demonstrated that in the past formulations were developed for applying by bath, the doses of which had to be modified to avoid problems of phytotoxicity, until the point when said doses are not effective, therefore said applications were not useful and disappeared. It has been effectively proven, for the purposes of this invention, that the use of effective doses are phytotoxic and in addition, the non-phytotoxic doses are, however, not very effective or ineffective. It occurred in the same way as has been explained with the formulation which was developed for the application thereof in drencher, bath or spray in line of application.

Example 1

Test for Determining the Efficacy and Phytotoxicity of a Post-Harvest Treatment Composition Based on 30% Cinnamic Aldehyde at High Doses (1,500 ppm)

(5) The fruit to be treated was Navelina orange and Clemenules mandarin.

(6) The product was applied by means of industrial drencher in the storage centre of the pieces of fruit to be treated with one single post-harvest application over 30 seconds, 24 hours after harvesting. Subsequently, the fruit was introduced into a chamber at ambient temperature for more than one month.

(7) It was proven that all the fruits showed, to a greater or lesser extent, staining and phytotoxicity. As can be observed in Tables 1 and 2, the formulation based on plant extracts used demonstrated, in the application thereof in drencher at the applied doses, the efficacy thereof in the control of the rotting of citrus fruits. However, the phytotoxicity produced makes its commercial use unviable.

(8) TABLE-US-00001 TABLE 1 Results of the analysis for the Navelina orange % % % Rotten % Ref. Treat. Rotten Efficacy Pen. spp. Efficacy II Thiabendazole 2.4 82.05 a 0.9 93.83 a 60% (3 mL/L) III Cinnamon 3.2 76.33 a 2.6 79.49 b extract (5 mL/L) O OBSERVER 14.13 .sup.0 b 14.0 .sup.0 c

(9) TABLE-US-00002 TABLE 2 Results of the analysis for the Clemenules mandarin % % % Rotten % Ref. Treat. Rotten Efficacy Pen. spp. Efficacy II Thiabendazole 5.63 38.69 ab 2.23 69.92 a 60% (3 mL/L) III Cinnamon 6.0 33.2 ab 1.57 76.54 a extract (5 mL/L) O OBSERVER 9.47 .sup.0 b 7.1 .sup.0 b

Example 2

Test for Determining the Efficacy and Phytotoxicity of a Post-Harvest Treatment Composition Based on 30% Cinnamic Aldehyde at Low Doses Combined with Synthetic Fungicides

(10) It was proven that all the combinations of the plant extract used on the same classes of fruits as in Example 1 with synthetic fungicides gave problems of phytotoxicity, as is shown in the photographs in FIG. 2.

Example 3

Compositions According to the Present Invention

(11) Below various compositions are described according to that which is described in the present invention, which have been tested on the same classes of fruits as in the previous examples, but unlike in those, they have shown absence of phytotoxicity. The concentration of the active substance used in the post-harvest treatment composition is shown in parentheses: Plant-strengthening formulation, which contains 50% potassium phosphite at the application doses of 0.3-0.35% (1,500-1,800 ppm of potassium phosphite)+plant extract, which is cinnamon extract (30% cinnamaldehyde) at an application dosis of 0.17%-0.34% (500-1,000 ppm of cinnamaldehyde) fungicidal formulation, which contains (45%) phosethyl acid at the application dose of 0.33-0.45% (1,500-2,000 ppm of phosethyl al)+plant extract, as has been described for the previous formulation** (500-1,000 ppm of cinnamaldehyde). Fungicidal formulation, as has been described in the previous formulation (1,500-2,000 ppm of phosethyl al)+plant extract, as has been previously described (500-1,000 ppm of cinnamaldehyde)+20% guazatine at the application dose of 0.5% (1,000 ppm of guazatine)

(12) None of the treatments showed phytotoxicity in oranges, mandarins, satsumas, clementvillas, lemons and clemenules, i.e. a wide sampling of varieties of commercialized citrus fruits.

Example 4

Application of a Post-Harvest Treatment Composition According to the Present Invention

(13) Industrial test in citrus fruits storage facility in Murcia with a variety of lemon.

(14) In the process, 20 pallets (approximately 20 tonnes of lemons) were introduced into the degreening chamber without treatment and 20 pallets treated in drencher with 30% cinnamaldehyde at 0.2% (600 ppm cinnamaldehyde) and with 50% potassium phosphite at 0.3% (1,800 ppm).

(15) At 7 days of degreening, the results were as follows: Control fruit, without treatment: 56% rotten by Penicillium digitatum Treated fruit: 5% rotten by Penicillium digitatum Efficacy of the treatment (Abbott*)=91% Phytotoxicity number of the treatment: 0%.

(16) Conclusions: the combined treatment of a composition formed by 30% cinnamaldehyde and 50% potassium phosphite in drencher has shown a high efficacy in the control of the rotting of post-harvest lemons, demonstrating the synergetic effect of the treatment. Similarly, the reductive effect of the strengthener has allowed the control of the oxidation of the fruits produced by the plant extract (cinnamaldehyde, also called cinnamic aldehyde), no type of staining of the fruits being produced.