WO2010109290A2

WO2010109290A2 - Compositions for the protection of crops, method for the application thereof and use of said compositions for the protection of crops

Info

Publication number: WO2010109290A2
Application number: PCT/IB2010/000603
Authority: WO
Inventors: Luis Fernando Echeverri Lopez; Francesc Xavier JUSTRIBÓ ABOS; Carles Zanuy Fontanet
Original assignee: Sustainable Agro Solutions, Sa
Priority date: 2009-03-26
Filing date: 2010-03-22
Publication date: 2010-09-30
Also published as: DOP2011000294A; ES2400218A1; BRPI1010291A2; CR20110501A; WO2010109290A3; ES2400218B1; ES2400218B8; ECSP11011414A; CO6460698A2; MX2011009878A; BRPI1010291B1

Abstract

The invention relates to compositions having the capacity to activate the natural defense mechanisms of plants against pathogenic microorganisms, especially fungal diseases, by means of the application of compositions based on natural carbohydrates. The composition comprises a combination of at least two natural carbohydrate derivatives selected from a group including cell wall polysaccharides, such as pectin; polysaccharides such as dextrin and exuded gums from plants such as gum tragacanth, xanthan gum, gum arabic, gum karaya or mastic gum.

Description

COMPOSITIONS FOR THE PROTECTION OF CROPS, METHOD FOR THE APPLICATION THEREOF AND USE OF SAH) COMPOSITIONS FOR THE

PROTECTION OF CROPS

Field of the Art

This invention relates to compositions having the capacity to activate the natural defense mechanisms of plants against pathogenic microorganisms, especially fungal diseases, by means of the application of compositions based on natural carbohydrates. These compositions have been designed biorationally, taking as a basis the structure of natural phytoalexin-eliciting substances and have a protective effect, lacking direct biocidal effects. Background of the Invention

The society is demanding with increasing emphasis foods which are healthier and more reliable, i.e., free of chemical and microbiological residues which can cause risks for the consumer. To achieve producing this type of foods which form part of Green or Organic Agriculture, the implementation of clean agricultural practices is currently analyzed since the protection of plants against pathogenic microorganisms has usually been achieved by means of the application of synthetic substances which generally have biocidal properties, i.e., they kill or considerably disturb their metabolism. Nevertheless, very few of them exert this action selectively, therefore side effects on other organisms are generated. A microbial resistance is also created at mid- or short-term which opens a vicious circle consisting of the need to apply larger amounts of pesticides to achieve moderately acceptable results; the production costs are thus increased and the environment is considerably affected in terms of flora, fauna, air, soil, water and even life itself and its quality in humans.

As a result of that mentioned above, the regulatory agencies of the European Union as well as of the United States have imposed severe limits to their use as well as the permissible levels in vegetables and their derivatives. For these reasons, it is essential and urgent to search for new alternatives to effectively control said microorganisms. One of them is the activation of the natural defenses of plants through the external application of substances which activate or modify the plant biochemistry in terms of its primary and secondary metabolites and of the latter, phytoalexins; due to the fact that the effects of these compositions are based on their biochemical interrelation of these substances with other molecules, a list of their main characteristics is shown below.

Phytoalexins are chemical compounds produced by plants as a consequence of the attack of microorganisms, especially fungi, in general terms they are similar to antibodies in animals. These molecules have an intense antibiotic activity and are considered as the starting point of a new generation of antibiotic substances, either applying them as such or inducing their generation through the application of substances called Elicitors. The plant thus exerts antibiotic effects in situ against a possible pathogen.

In addition, the induction or elicitation of secondary metabolites of the phytoalexin type is an alternative by means of which the plant adapts to a physical, biochemical or microbial stress. This is carried out through the interaction of the plant cell with some oligosaccharides coming from the mycelium of several fungi or derivatives thereof, such as filamentous glycosphingolipids derived from fungi (US Patent 7,316,989). These substances are known as Elicitors and have been considered for the future as a good alternative for pathogen control, since they would act in a manner similar to a vaccine in animals, inducing transient levels of phytoalexins, such that when the pathogenic microorganism germinates or starts colonizing the plant, the latter has a high accumulation of antibiotic substances. Once the risk of infection disappears and the application of the elicitor ends, the plant restores its normal biochemistry and the levels of phytoalexins decrease or disappear. The latter fact prevents the presence of substances which can be hazardous for human health such as for example estrogenizing effects, phytotoxic effects or others, which depend on the type of plant. The main source of possible elicitors are natural carbohydrates such as soybean heptasaccharide and in fact a tamarind xyloglucan was patented as a protector (US Patent 5,602,1 1 1). Due to their nature itself, the synthesis of inducing oligosaccharides is complex and obtaining them from natural sources is very difficult due to the low at which they are active. For such reason, it is necessary to search for other substances equally effective in their inducing capacity.

Additionally, Phytoprotectants are substances which provide protection to the plants against microorganisms by non-biocidal methods, i.e., they are not directly antibiotic, but rather they induce the formation of defense mechanism therein. Although some phytoprotectants such as acibenzolar, lactofen, salicylic acid, jasmonate and the benzothiadiazole, among others, are already known, the current trend is to search for natural substances which exert this biological activity, since the problems inherent to not knowing their possible deleterious side effects would be avoided.

Pectin is a polysaccharide of interest as an elicitor. It is a very complex oligogalacturonide which is located in the cell wall of plants; it is mainly formed by several monomers derived from rhamnose, galactose with different types of bonds, i.e., residues of D- galactosyluronic acid (GaIpA) with 1,4 bonds which basically form three types of polysaccharides: type I branched rhamnogalacturonans, substituted galacturonans and a homogalacturonan domain with different degrees of methylation. Industrially, it is mainly obtained from citrus and apple tree and is used as a gelling agent in the food industry. Its use is also accepted by the FDA and the European Union (FAOAVHO Joint Expert Committee on Food Additives (JECFA Website). As in the previous case, it is also considered as a GRAS (Generally Recognized As Safe) substance in the United States and is included in the Codex alimentarius. Its presence or the presence of its degradation products has also been associated with the resistance of plants against pathogens {Brent L. et al. Phytochemistry 57 (2001) 929-967. Pectins: structure, biosynthesis, and oligogalacturonide-related signaling).

In addition to those mentioned above, there are other types of phytoalexin-inducing substances, among them aminated compounds. For example, it has been verified that several natural aminoglycosides induce phytoalexins in plantain and papaya. Another important phytoalexin inducer is chitosan, which is also a natural aminated compound the eliciting activity of which forms part of a number of patents.

The combination of polysaccharides with peptides also has effects on the physiology of plants, providing improvements in the crop yield (US Patent 2002/0166147), improvements in the emergence, growth and root development of seeds (US Patent 2005/0256001) or inhibition of the development of phytopathogens such as fungi (US Patent 6,844, 181).

Within polysaccharides, a group of important industrial interest due to the properties thereof are exuded gums, the structure of which is complex and varies according to the origin and age. These gums are obtained from different trees and have properties for a large amount of applications. Some of the gums with greater industrial interest are gum arabic, gum tragacanth, gum karaya and xanthan gum. Their use is usual in the food industry due to their emulsifying properties and properties for improving the texture of food preparations, although there are applications in industries as diverse as the pharmaceutical or paint manufacture industry, or even medical applications.

In the agronomy field, gums have been used for years in compositions for the protection of crops, although their use is focused on using them as thickeners or adhesive agents to improve the effect of some fungicidal compound. In this sense, the use of gum tragacanth (GB Patent 528,054), of xanthan gum (US Patent 5,424,270 and US 5,464,805) has been patented.

Recently, some studies indicate the induction capacity of xanthan gum, for the protection against diseases in coffee (Guzzo, S.D. et al. "Crude Exopoly saccharides (EPS) from Xanthomonas campestris pv. manihotis, Xanthomonas campestris pv. Campestris and Commercial Xanthan Gum as Inducers of Protection in Coffee Plants against Hemileia vastatrix") or barley (Castro, O.L. et al. "Increased production of β-1,3 glucanase and proteins in Bipolar is sorokiniana pathosystem treated using commercial xanthan gum").

In the Musaceae family, several phytoalexins of the phenyl-phenalenone type have already been described and their synthesis, biosynthesis and antifungal activity have already been demonstrated, and some derivatives have a high activity against Black Sigatoka.

For the purposes of nomenclature herein, plantain is understood as any of the plants of the Musaceae family and their fruits, also called bananas, always taking into account that it is a fruit belonging to the Musaceae family but having certain differences relating to size, color and taste.

Black Sigatoka is a fungal disease caused by the Mycosphaerella fijiensis fungus which causes considerable losses in the quality and extra costs in banana production, since it generates spots in the leaves which cause a considerable decrease of the crop yield. Brief Description of the Invention The object of this invention is to supply substances which modify the biochemistry of plants, activating several defense mechanisms, such that when a pathogenic microorganism appears, its action is neutralized by those preformed defenses. From that point of view, those compositions are not biocidal and offer a mechanism of action which is effective, environmentally friendly and safe for humans. The design of these substances was taken based on the structure of several oligo- and polysaccharides called Elicitors, which have the capacity to induce the production of phytoalexins, substances having a recognized antibiotic activity.

Due to the fact that the mechanism of action of these substances is virtually universal for all plants, since they involve the activation of natural defenses, these compositions and the methodology can be applied to all the plants requiring a non-biocidal defense elicitation mechanism against pathogenic microorganisms.

According to the invention, a composition for the protection of crops suitable for controlling pathogenic microorganisms is proposed, which composition comprises a combination of at least two natural carbohydrate derivatives selected from one of the following groups:

- Cell wall polysaccharides, such as pectin. - Polysaccharides such as dextrin.

- Exuded gums from plants: such as gum tragacanth, xanthan gum, gum arabic, gum karaya or mastic gum.

- Monosaccharides such as Glucosamine.

At least one of the natural carbohydrate derivatives is preferably selected from Pectin, Glucosamine and Gum Karaya.

According to a preferred embodiment of the invention, the proposed composition comprises two of said natural carbohydrate derivatives.

In an embodiment of the invention, the composition comprises Gum Karaya and at least one of the mentioned natural carbohydrate derivatives, for example, a natural carbohydrate derivative selected from Pectin and Glucosamine.

The composition comprising Pectin and Gum Karaya has shown a great effectiveness applied to the treatment of banana crops.

The crops to be treated by means of the compositions of this invention are preferably selected from the families of solanaceae (e.g., pepper, potato, tomato), musaceae (e.g., plantain/banana), rosaceae (e.g., rose), vitaceae (grape), cucurbitaceae (e.g., melon, watermelon, zucchini, cucumber) plants and several families of ornamental plants such as carnation.

The compositions are preferably intended for tomato, plantain/banana, rose, grape and melon.

In particular, the crops in which the compositions of the invention have been applied are plants of banana Musa AAA Cavendish Var. banana plants. Illustrative Figure of Results

Figure 1 illustrates the results found according to the Examples detailed below. Description of Several Embodiments of the Invention Examples The following examples are included to illustrate the protective activity of carbohydrates in the development of the plantain disease known as Black Sigatoka, caused by Mycosphaerella fijiensis fungus. It should be noted that for this disease its severity is always increased and the available treatments exert a retarding effect of the effects and dissemination thereof, such that the leaf is still biochemically viable for the plant to generate a suitable fruit. Example no. 1. Evaluation of five substances on the control of Black Sigatoka in banana in field conditions.

This test plans to analyze in the field the effect of various combinations of substances due to their protective activity against Black Sigatoka in the field, using the Single Leaf Test.

The following treatments were used:

All the substances were products purchased in SIGMA, St Luis (Mo., USA), except the Tridemorph, which was obtained from a local supplier. Agricultural oil was furthermore used.

For the preparation of the emulsions, first the agricultural oil, humectant-adhesive agent and water ( 149 mL) were mixed in a homogenizer for at least 60 seconds; subsequently the substance to be studied in three successive portions and finally water are added. The stirring is continued until the complete homogeneity of the material.

All the mixtures were prepared simulating an application of 5 American gallons (18.92 liters per hectare). 500 cc of each mixture were prepared and each leaf of all the test plants was sprinkled with the aid of a garden pump. General conditions of the test:

• The present work was performed in an experimental Gran Enano variety banana plantation located in the municipality of Carepa-Antioquia-Colombia at a height of 80 m.a.s.l., average temperature of 30 degrees centigrade and an annual average precipitation of 3,600 mm.

• The material used is Cavendish with high susceptibility to suffering from the disease; the test consists of four random repetitions, and each repetition is a plant developed with only the already mentioned leaves, when the sprinkling can be carried out with a garden pump it is done so, otherwise it will be done with a sponge • Test start date: June 21 , 2008

• No. of Treatments: 13

• No. of repetitions/treatment: 4

• Total experimental units: 52

• The test was started with 2 leaves/plant, assuring initial severity = 0; the number of leaves of the plant when the experiment ended was 10-1 1. Every 5 days the number of infection points and the state of the three most recent leaves were determined; the number of leaves of the plant when the experiment ended was 10-1 1 • The evaluations were performed on the dates June 21-08 (0 DAA, Days after the first application), June 25-08 (5 DAA) and June 30-08 (10 DAA), July 5-08 (15 DAA), July

10-08 (20 DAA), July 15-08 (25 DAA), July 20-08 (30 DAA), July 25-08 (35 DAA), July 30-08 (40 DAA) and August 1 1-08. The scale of evaluation of the severity of the disease according to Stover's concept modified by Gahul was calculated by the following formula: T.L. in 1 * 0.01 + T.L. in 2 * 0.05 + T.L. in 3 * 0.15 +T.L. in 4 * 0.33 + T.L. in

5 * 0.5 + T.H in 6 * 1/ total number of leaves * 100, where T.L.: Total leaves.

Grade 0: without any symptomatology of the disease Grade 1 : less than 50 spots in the entire leaf.

Grade 2: more than 50 spots or necrosis: 1-5% in the entire leaf

Grade 3: 6-15% necrosis in the entire leaf.

Grade 4: 16-33% necrosis in the entire leaf.

Grade 5: 34-50% necrosis in the entire leaf. Grade 6: greater than 50%

On June 21, 2008, the date on which the first application was performed, there was a precipitation of 4 mm at 5:30 P.M.

Results > The averages obtained by date of evaluation by treatment of leaves/plant indicate a normal development of the plant and consequently there is no adverse effect in any of the treatments in relation to leaf sprouting.

> There was no phytotoxicity symptom in any of three applications performed in the 12 treatments applied. > Ten days after the first application (July 1, 2008) it is observed that the Tridemorph,

Pectin+Gum Karaya, and Pectin+Glucosamine treatments present lower severity indexes, 1.60-1.88-1.88 respectively.

> The evaluation of July 6, 2008 showed that the treatments which has a better control of the disease were Tridemorph and Pectin+Karaya (2.09, 2.28 respectively). > The third and last application was performed on July 8, 2008 and three days later (July

1 1 , 2008) the treatments which responded better were Tridemorph and Pectin+Glucosamine, with severity values of 2.27 and 2.46 respectively. The fact that the Pectin+Glucosamine treatment appears again as one of the best in terms of control, having performed the 3 applications, indicates that it is among the best treatments and it is necessary to take it into account for new assays.

> The average of leaves on July 1 1 of the best treatments (Tridemorph, Pectin+Glucosamine and Pectin+Gum Karaya) were 5.5, 5.2 and 5.5. Tridemorph and the Pectin+Gum Karaya treatment have on average 5.5 leaves unlike the Pectin+Glucosamine treatment which has by that date a lower average (5.25 leaves per plant). Leaves no. 4, 5, 6 of all the treatments have severity grade 2, although of course, the treatments having a higher average of leaves tend to have a higher severity.

> By July 16, 2008 (8 days after the third application) the Tridemorph treatment still stands out as the best. There is a phenomenon which starts to be manifested and it is that a treatment fluctuates as good in one reading and as not good in the next reading or readings and vice versa. This analysis can be quite complex, although the following applications exist:

^■ If there is leaf sprouting, the severity of course decreases, since the severity in leaf no. 1 in all the plants of the 13 treatments in the 11 evaluations performed was 0.

^■ The initial development of the disease is thus: S Germination (3-6 hours)

S Penetration (4-6 days)

^■S Incubation (1 1-15 days). It must be taken into account that this range can have variations due to reasons of weather, infection intensity and vigor of the affected plant. S Onset of first symptoms: 20 to 30 days after the penetration.

These 2 factors which cannot be controlled in the field directly affect the results obtained in the severity formula.

> In relation to the evaluation of July 21, 2008, the Pectin+Dextrin and Pectin+Mastic gum treatments again mark the difference (and severities of 3.75 and 3.75 respectively) whereas it is 3.10 for Tridemorph. The Pectin+Dextrin and Pectin+Mastic gum treatments thus stand out for the first time in terms of the control of the disease.

> By July 26, 2008, i.e., 18 days after the last application the treatments which showed a better behavior were Pectin+Gum Arabic (severity 3.83), Pectin+Dextrin and Tridemoφh with identical severity (3.87). This could indicate that the Pectin+Gum Arabic treatment, which in the last evaluation occupied the fourth place, involves a defense mechanism in the plant, because 18 days have elapsed from the last application and this treatment is even being better on this date of evaluation than the commercial control, Tridemoφh. It should be noted that in some countries a product is considered systemic if the application interval is 15 days at most, but if they have a residual effect in the plant these treatments start to respond.

> On July 31, 2008 the treatments which exerted a greater control corresponded to Pectin+Gum Karaya, Pectin+Glucosamine and Tridemoφh (severity of 4.04, 4.16 and 4.21 respectively). Given that the Pectin+Glucosamine treatment again appears among the best and to this date 23 days have elapsed from the last application, it could be inferred that the active ingredient has a systemic power and remains or has a control effect on the fungus.

> In the evaluation of August 5, 2008 the treatments which stand out most due to their control are already seen. According to the order, the best of that date were Tridemoφh and Pectin+Gum Karaya, with severity values of 3.88 and 4.07 respectively. It seems that the Pectin+Glucosamine products lost their control effect, because by this date 28 days had already elapsed after the third and last application. The following table shows how the severity for this product increases considerably in the last two evaluations in relation to the rest, which could involve that during those 28 days the substance would have had to be applied again, which does not rule it out as another possible protector:

> For the final date of evaluation (August 1 1-2008), it is concluded that the best treatments were still the same as those of the previous date, Tridemorph (reference compound) and Pectin+Gum Karaya, with severity results of 4.88 and 5.25 respectively.

^ It seems that there are two types of substances and/or of mechanisms of action involved; on one hand, some products perform an early control of the disease, such as Pectin+Glucosamine, whereas Pectin+Gum Karaya have a long-term effect. According to what is observed, the Pectin+Glucosamine treatment has a control over the disease, but of shorter intervals in relation to the Pectin+Gum Karaya treatment. It is important to note that significant differences between the Pectin+Glucosamine treatment and the Pectin+Gum Karaya treatment were only presented in the last date of evaluation performed on August 1 1, 2008. Such a product is interesting because with the existing protective molecules on the market (they only inhibit the germination of the germ tube) the control days range between 6 to 9 days.

In short, several compositions, including Pectin+Glucosamine and Pectin+Gum Karaya, have Black Sigatoka-controlling effects, Pectin+Gum Karaya having a protection period which lasted for almost the entire treatment, whereas Pectin+Glucosamine has a greater control in more reduced periods after the application.

Notes

It must be emphasized that with treatment no. 2, in the evaluations corresponding to July 26 and July 31, 2008 there was a decrease of the severity (3.87 and 3.78 respectively), which is due to the fact that in the evaluation of July 31, 2008 repetition no. 4 lost leaves 5 and 7 and therefore the value with the severity formula decreases. Therefore, this treatment was not taken into account as the one of best control on the date of July 31 , 2008, the best result in the severity formula gave (3.78).

• Treatment No. 4 had a decrease in the severity between the evaluations dated July 31 to August 5, 2008 (4.04 and 3.96 respectively), therefore in the last evaluation plant no. 2 had a grade 0 in leaf 2, unlike the evaluation of July 31, 2008, in which leaf no. 2 of all plants had grade 1 of disease attack. Of course, this makes the value of the severity formula decrease.

• Another similar case occurred with treatment no. 6. On July 31 and on August 5, 2008 the severity changed from 4.21 to 3.88. It occurred that on August 5, 2008, plants 1 and 4 had a grade 0 in leaves No. 2, which caused the severity to decrease considerably in relation to the previous evaluation. Example no. 2.

Comparative efficacy with respect to commercial fungicides in the preventive control of Black Sigatoka (Mvcosphaerella fijienses var. difformis Morelet) in banana (Musa acuminata Colla AAA) in Uraba (Colombia) by means of single leaf protocol.

To determine the comparative efficacy for the preventive control of Black Sigatoka of the Pectin + Gum Karaya mixture, another experiment was performed simultaneously analyzing said molecules with three other substances of commercial use, a protector and two systemic substances. Furthermore, the phytocompatibility of the treatments in the treated plants was evaluated.

The test was performed in the Lote La Antena experimental plot, located in Carepa, Uraba, Antioquia department (Colombia) in a Gran Enano variety banana plantation with an annual average temperature of 26 degrees centigrade, relative humidity of 87% and annual average precipitation of 3,000 mm. Furthermore, the precipitation were recorded daily (before and at the end of the test).

The agronomic handling of the plot was the commercial one, except in relation to the application to the consumables for which the test was in charge. In relation to the Sigatoka attack, Lote La Antena, compared to Uniban Central, has a high level of inoculum and severity of the diseases given the natural conditions. From each plant, rectangles of 5 x 7 cm on the underside of each leaf and treated on the upper side with a single application of the treatments, at the start of the test, were selected and the leaf area with Sigatoka in percentage (stages I to IV), leaf area with necrosis by Sigatoka in percentage (stages V and VI) and predominant stage were periodically evaluated. The parameters to be evaluated in a central box of 7 cm. X 5 cm. located on the underside of the leaf) related the severity of the incipient development of the fungus in percentages of I-V stages, the severity in percentage stage VI (necrosed tissue) and the predominant stage.

The plants had 1 m of stature from the base to the bunchy top at the start of the test, four true leaves and shooting degree between 0.0 and 0.4, at the start of the test. The plants in the test were healthy and normal at the start thereof and had an optimal agronomic handling similar to the commercial one. The fungicides were applied in emulsion and solution to a 5 gallons/hectare (18,925 liters) mixture volume, conserving the dose proportion. 500 cc of mixture were prepared for each treatment for a total of 9 treatments (the absolute control is included) with 7 repetitions, for a total of 63 plants under study.

The Treatments and the form of preparation are shown in Table 1; with the exception of Chlorothalonil which was prepared in aqueous solution, all the Treatments were prepared in emulsion form, using to that end PEGAL and an oil.

The dates of evaluation were: November 15, 2008 (0 DAA, days after application),

November 20 (5 DAA), November 25 (10 DAA), November 30 (15 DAA), December (20 DAA), December 10 (25 DAA) and December 15 (30 DAA).

Monitoring was performed over time of possible phytotoxicity symptoms, if any. ANOVA or F-test at 5% of statistical confidence will be used to establish if the treatments significantly differ from one another. Results

The following results were found (Figure 1):

• Taking as an example plant no. 2 of the absolute control (no product applied), the development of the disease was as follows: 5 DAA (days after application predominance of stage I (less than 50 stages), 10 DAA predominance of stage II (less than 50 stages),

15 DAA onset of stage IV (more than 50 stages), 20 DAA onset of stage IV (more than 50 stages), 25 DAA onset of stage V (more than 50 stages), 30 DAA onset of stage VI (more than 50 stages).

• After 30 DAA, in addition to the absolute control, the only commercial treatment which presented necrosis (formation of perithecia) was the solution Chlorothalonil 720 SC in plants no. 1, 3 and 6 with percentages of 10, 15 and 10%.

• In this same lapse of time, the best treatments in terms of the control of the disease corresponded to Emulsion Tridemorph and Pectin+Gum Karaya (2%) with relative areas of Sigatoka (sum of stages I to V) of 41.4 and 32.1% respectively. There were no statistical differences between these treatments.

Figure 1. Course of the evolution of Black Sigatoka under the treatment with several products.

• There were no statistical differences between the treatments Emulsion of the mixture Pectin+Gum Karaya at 1% and at 2%. It is important to note that said treatments had a better control of the disease in relation to the percentage of area with Sigatoka, comparing them with the Emulsion Pegal and Emulsion Dithane 60 OF treatments.

• It should be noted that 35 DAA there is a small percentage of area affected by Black Sigatoka (slightly more than 20%), whereas in the control this area is close to 80% and in other treatments such as Chlorothalonil and Dithane it is considerably higher (Figure 1). • After 10 DAA (days after application) the absolute control treatment had statistical differences in relation to all the commercial treatments.

• All the mixtures had normal stability, since there was no phase separation.

These results become more important if it is taken into account that there was only one application of each substance, which is not usual, since to combat this fungus it is necessary to apply a program including several agrochemical products up to 4 or 5 times.

Claims

1.- A composition for the protection of crops against pathogenic organisms which comprises a combination of at least two natural carbohydrate derivatives selected from a group including cell wall polysaccharides, such as pectin; polysaccharides such as dextrin and exuded gums from plants such as gum tragacanth, xanthan gum, gum arabic, gum karaya or mastic gum.

2.- The composition according to claim 1, characterized in that at least one of the natural carbohydrate derivatives is selected from Pectin, Glucosamine and Gum Karaya.

3.- The composition according to claim 1, characterized in that it comprises Gum Karaya and at least one of the mentioned natural carbohydrate derivatives.

4.- The composition according to the previous claims, characterized in that it comprises Gum Karaya and at least one natural carbohydrate derivative selected from Pectin and Glucosamine.

5.- The composition according to claim 4, characterized in that it comprises Gum Karaya and Pectin.

6.- The composition according to the previous claims, characterized in that the crops to be treated are selected from the families of solanaceae (e.g., pepper, potato, tomato), musaceae

(e.g., Plantain/banana), rosaceae (e.g., Rose), vitaceae (grape), cucurbitaceae (e.g., melon, watermelon, zucchini, cucumber) plants and several families of ornamental plants such as carnation.

7.- The composition according to claim 6, characterized in that said crops are selected from tomato, plantain/banana, rose, grape and melon.

8.- The composition according to claim 8, characterized in that said crops are Musa spp. banana plants.

9.- The composition according to claim 1, characterized in that said pathogenic microorganisms are the Mycosphaerella fijiensis fungus.

10.- The composition of claims 1 and 2, wherein a carbohydrate is Pectin, preferably from apple, in amounts comprised between 1.0%-4.0% by dry weight.

1 1.- The composition of claims 1 and 2, wherein the carbohydrate is Gum Karaya, in amounts comprised between 1.0%-4.0% by dry weight.

12.- The composition of claims 1 and 2, wherein the carbohydrate is Glucosamine, in amounts comprised between 1.0%-4.0% by dry weight.

13.- The composition of claim 5, wherein the carbohydrates are Pectin and Gum Karaya, in amounts comprised between 1.0%-4.0% by dry weight, of which between 10%-25% by dry weight correspond to Pectin.

14.- The composition of claims 1 and 2, wherein the carbohydrates are Pectin and Glucosamine, in amounts comprised between 1.0%-4.0% by dry weight, of which between 10%- 25% by dry weight correspond to Glucosamine.

15.- The composition of claim 4, wherein the carbohydrates are Glucosamine and Gum Karaya, in amounts comprised between 1.0%-4.0% by dry weight, of which between 10%-25% by dry weight correspond to Glucosamine.

16.- The composition of claim 6, wherein the selected crop consists of fruits, leaves, grains, legumes, seeds, flowers, pastures, roots, ornamental plants and crop plants.

17.- A method for the application of compositions for protecting crops, wherein the compositions are applied by immersion, spraying or painting.

18.- A method according to claim 17, wherein the compositions are applied mixing them with a fertilizer.

19.- Use of a composition according to one of claims 1 to 16, for the protection of crops by means of controlling pathogenic microorganisms of said crops.