TECHNICAL FIELD

The present disclosure relates generally to compositions for protecting plants from pathogens; and more specifically, to use of compositions comprising rosin and at least one solvent for seed treatment. Furthermore, the present disclosure also relates to methods of treating seeds using the aforementioned compositions.

BACKGROUND Generally, many species of plants around the world have developed different ways of protecting themselves from herbivores. For example, some plants develop thorns on their leaves or stems to prevent herbivores from eating them while others secrete poison capable of incapacitating or fatally wounding the herbivores that try to consume them. Furthermore, while some trees may not possess an ability to defend themselves from injury caused by herbivores, the trees secrete resin to protect themselves from further injury and/or to repair damage caused by such an injury. However, in-spite of all these defence mechanisms, plants are still incapable of defending themselves from pathogens and microbes.

For centuries, farmers have used various techniques to defend crops from attack by pathogens and/or microbes. One such technique is associated with use of lime and wood ash to eliminate parasites that could potentially lay waste to entire crop-fields. Also, pesticides derived from petrochemical products such as crude oil, sulphur and bitumen are conventionally well-known to protect plants. Furthermore, metal-based pesticides employing copper, lead and/or mercury have been used as common pesticides and biocides. Usually, such pesticides are sprayed over the crop-fields to prevent the growth of pathogens and/or microbes on the crops.

Although widely used, chemical pesticides and biocides (such as, pesticides and biocides employing petrochemical products, metal-based pesticides and biocides, and so forth) are associated with major drawbacks. Firstly, chemical pesticides are toxic to both organisms that they are intended therefor such as the pathogens and/or microbes, and also to other organisms such as cattle, stray animals, pets and even humans. Secondly, certain chemical pesticides are often effective for only a short period on particular organisms. In such instances, the organisms become immune to the chemical pesticides after prolonged exposure thereto and consequently, the chemical pesticides may no longer be effective in preventing growth and harm to the crops by the organisms. Thirdly, accumulation of the chemical pesticides may lead to bio-magnification, wherein chemical residues of the chemical pesticides left behind in the crops or plants, makes them unfit for human or animal consumption. Furthermore, the chemical pesticides may soak into soil in the crop-fields and/or underground water used for irrigation in the crop-fields, thereby contaminating the soil and/or underground water with the chemical residues. It will be appreciated that when such contaminated soil is exposed to animals and/or humans, the contaminated water is used to spray the crops, or used for animal or human consumption, the animals and/or humans may be at great risk of experiencing severe damage including brain damage, cancer or even death.

An alternative to such conventional techniques of spraying crop-fields with chemical pesticides is performing seed treatment. In agriculture and horticulture, seed treatment or seed dressing is a compound, typically antimicrobial or fungicidal, that is used for treating (or "dressing") seeds prior to planting thereof. While seed treatment employs comparatively smaller quantities of chemical pesticides than spraying of crop-fields, the technique still poses various risks. One such risk is accidental exposure of workers performing the seed treatment to the chemicals used for the seed treatment, wherein such chemicals can be harmful to the workers. Another major risk is causing harm to the sensitive seeds by exposure thereof to the chemicals, thereby, leading to unsuccessful growth (or premature death) of crops. Furthermore, food supplies resulting from the plants or crops grown from the treated seeds may be contaminated by the chemicals. It will be appreciated that consumption of such food supplies can be detrimental to health and well-being of humans and/or animals consuming the food supplies.

Despite the aforementioned problems, relevant documents addressing these issues have not been found. CN106259564 A discloses a coating film for corn seeds, wherein the coating film aims at keeping the normal water content required for seed germination and for preventing seeds from being inactivated due to water shortage. EA027877 B1 relates to prevention of rapeseed pod from cracking by forming a coating about the pod. Arruda et al (2007) studied the possible phytotoxic effects of some natural and synthetic substances potentially repellent to wild fauna. However, these references do not relate to antimicrobial or antifungal seed treatment or seed dressing.

In the view of the aforementioned discussion, there exists a need to overcome the aforementioned drawbacks and risks associated with use of chemicals to defend plants and crops from pathogens and microbes. SUMMARY

The present disclosure seeks to provide a use of a composition comprising rosin and at least one solvent for seed treatment. The present disclosure also seeks to provide a method of treating seeds using the aforementioned composition. The present disclosure seeks to provide a solution to the existing problem of protecting plants from microbial pathogens without causing harm to the plant or the environment. An aim of the present disclosure is to provide a solution that overcomes at least partially the problems encountered in prior art.

In one aspect, an embodiment of the present disclosure provides a use of a composition comprising rosin and at least one solvent for seed treatment.

In another aspect, an embodiment of the present disclosure provides a method of treating seeds, comprising:

- providing a solution of rosin and at least one solvent,

- spraying the solution on the seeds, and

- drying the sprayed seeds.

Embodiments of the present disclosure substantially eliminate or at least partially address the aforementioned problems in the prior art, and provide the composition that is effective in concentrations significantly smaller as compared to conventional products for its use in treating seeds for protecting seeds from pathogens and microbes in the environment. Additional aspects, advantages, features and objects of the present disclosure would be made apparent from the drawings and the detailed description of the illustrative embodiments construed in conjunction with the appended claims that follow.

It will be appreciated that features of the present disclosure are susceptible to being combined in various combinations without departing from the scope of the present disclosure as defined by the appended claims. BRIEF DESCRIPTION OF THE DRAWINGS

The summary above, as well as the following detailed description of illustrative embodiments, is better understood when read in conjunction with the appended drawings. For the purpose of illustrating the present disclosure, exemplary constructions of the disclosure are shown in the drawings. However, the present disclosure is not limited to specific methods and instrumentalities disclosed herein. Moreover, those skilled in the art will understand that the drawings are not to scale. Wherever possible, like elements have been indicated by identical numbers. Embodiments of the present disclosure will now be described, by way of example only, with reference to the following diagrams wherein:

FIGs. 1A to 1C are graphical representations of average growth of fungi that is grown for a predefined period of time, in different concentrations of composition comprising rosin and at least one solvent, under dark conditions, in accordance with an embodiment of the present disclosure;

FIGs. 2A to 2E are graphical representations of average growth of fungi that is grown for a predefined period of time, in different concentrations of composition comprising rosin and at least one solvent, exposed to near visible ultraviolet (NUV) light, in accordance with another embodiment of the present disclosure; and

FIG. 3 illustrates steps of a method of treating seeds, in accordance with a further embodiment of the present disclosure. FIG. 4 illustrates results obtained in preventing leaf stripe of barley in field trials when barley seeds were treated with different concentrations of composition comprising rosin and water as solvent before sowing. Treatments: 1 - no treatment; 2 - water; 3 - 500 g ai/100 kg seeds; 4 - 750 g ai/100 kg seeds; 5 - 1000 g ai/100 kg seeds; wherein ai = active ingredient, sodium salt of rosin.

FIG. 5 illustrates results obtained in preventing formation of heads with smut in oats in field trials when oat seeds were treated with different concentrations of composition comprising rosin and water as solvent before sowing. Treatments: 1 - no treatment; 2 - water; 3 - 500 g ai/100 kg seeds; 4 - 750 g ai/100 kg seeds; 5 - 1000 g ai/100 kg seeds; wherein ai = active ingredient, sodium salt of rosin.

In the accompanying drawings, an underlined number is employed to represent an item over which the underlined number is positioned or an item to which the underlined number is adjacent. A non-underlined number relates to an item identified by a line linking the non-underlined number to the item. When a number is non-underlined and accompanied by an associated arrow, the non-underlined number is used to identify a general item at which the arrow is pointing.

DETAILED DESCRIPTION OF EMBODIMENTS

The following detailed description illustrates embodiments of the present disclosure and ways in which they can be implemented. Although some modes of carrying out the present disclosure have been disclosed, those skilled in the art would recognize that other embodiments for carrying out or practising the present disclosure are also possible. In one aspect, an embodiment of the present disclosure provides a use of a composition comprising rosin and at least one solvent for seed treatment. In another aspect, an embodiment of the present disclosure provides a method of treating seeds, comprising:

- providing a solution of rosin and at least one solvent,

- spraying the solution on the seeds, and

- drying the sprayed seeds.

The present disclosure provides the aforementioned use of the composition for seed treatment and the aforementioned method of treating seeds using such composition. The composition comprises rosin, which is a wood-based bioactive ingredient possessing antimicrobial, antibacterial, antifungal and antiviral properties. The rosin is readily soluble in solvents, such as an organic solvent. Notably, such solvents are highly volatile and evaporate with relative ease, resulting in formation of a protective layer of rosin around the seeds treated with the composition comprising rosin and at least one solvent. Additionally, rosin is less harmful as compared to commercially- available pesticides and therefore, is suitable for use for protecting plants, specifically at the seed germination level, without leading to any unpredictable environmental interactions. Furthermore, a small concentration of rosin is already effective in preventing the growth of fungi, as compared to substantially high concentrations of chemicals in pesticides. The aforementioned composition and its use for seed treatment is highly efficient, cost effective and environmentally-safe.

It will be appreciated that plants, especially seeds, are subjected to growth of fungus thereon, such as, during exposure to environmental conditions during various stages of plant growth, ranging from seed germination to fruit-formation.

Throughout the present disclosure, the term " fungus " or "fungi" as used herein, refers to a group of eukaryotic organisms that include microorganisms such as yeast, moulds and mushrooms. Fungi are the most widely distributed organisms on earth and exist in either free-form in soil, air and water or in symbiotic relationships with other organisms, such as plants, animals, parasites, other fungi and humans, for their nutritional needs. Fungi have long been used as a source of human food and in processing thereof. Moreover, fungi have been employed in production of antibiotics and various industrial applications, such as detergents. Despite the benefits, some bioactive compounds produced by fungi are toxic to plants, animals and humans. Typically, the plants inherently produce antifungal compounds, such as resins, gums, phytotoxins, polyphenols, saponins, fatty acids, essential oils, flavonoids, peptides and so forth, to resist the fungal infections. However, it will be beneficial to identify and exercise preventive measures for combating the fungal growth on the plants.

The present disclosure provides use of the composition comprising rosin and the at least one solvent for seed treatment. Throughout the present disclosure, the term " composition " as used herein refers to a plant growth regulating agent that is applied externally to the plant surface, such as by spraying, dusting or dipping the plant therein and so forth. It will be appreciated that the term " plants " as used herein refers to a plant in whole or in parts, such as seeds, root, stem, flowers, leaves and so forth.

The term "rosin" as used herein refers to a solid form of a plant-based ingredient 'resin' obtained, generally, from coniferous trees and pines. Rosin possesses antimicrobial, antibacterial, antifungal and antiviral properties and can be used in protecting plants from various bacteria, viruses and fungi present in the environment surrounding the plant treated with the rosin. It will be appreciated that naturally existing rosin comprises various bioactive ingredients, such as acids and other derivatives. Typically, rosin exists in nature in either a solid form or free form. Optionally, the rosin is in a form of free rosin acid or in a form of its alkali metal, earth alkali metal, ammonium or amine salt. More optionally, the free rosin acid comprise largely abietic acid, pyroabietic acid, dehydroabietic acid, 7a-hydroxydehydroabietic acid, 7b- hydroxydehydroabietic acid, 15-hydroxydehydroabietic acid, 7a, 15- hydroxydehydroabietic acid, 73,15-dihydroxydehydroabietic acid, 18- hydroxydehydroabietic acid, pimaric acid, sapinic acid and the like rosin acids and/or mixtures thereof, and the alkali metal salt of rosin comprise for example a sodium salt of rosin, potassium salt of rosin, and the like. Furthermore, commercially available form of rosin, i.e. tall oil rosin comprises rosin in the form of at least one of the free rosin acid or the sodium salt of rosin. More specifically, the biological activity of the free rosin acid and the sodium salt of rosin are typically identical. However, the sodium salt of rosin is soluble in water while the free rosin acid in solid form is insoluble in water. Furthermore, the insolubility of solid form of rosin in water contemplates the use of a solvent, such as an organic solvent, including but not limited to, an acetic acid, an alcohol, turpentine, acetone, ethyl acetate, and an ether, that dissolves the rosin. As mentioned earlier, the solvent may also be water. For example, the composition may comprise a commercially available rosin, such as the tall oil rosin (CAS-number 8050-09-7), and at least one alcohol. The composition may also comprise (in addition or alternatively) an ammonium or amine salt of rosin.

Moreover, differences in physical and chemical properties of both the free rosin acid and the alkali metal salt of rosin can be used and combined in an appropriate manner, to provide an overall protection to the plant. In an embodiment, the composition comprises a combination of the free rosin acid and the alkali metal salt of rosin and at least one solvent, such as aqueous alcohol, particularly in such amounts that both the free rosin acid and the alkali metal salt or rosin are soluble. It will be appreciated that the use of the composition comprising rosin and at least one solvent for seed treatment requires subjecting the seeds to such composition. Preferably, the composition comprising both forms of rosin and at least one solvent when applied to the plant results in a dual benefit to the plant. In an example, the composition comprising rosin and the at least one solvent when used for seed treatment, the at least one solvent evaporates over a period of time leaving behind a protective coating of free rosin acid around the plant, while the alkali salt of rosin, such as for example a sodium salt of rosin, provides its antimicrobial effect also to the environment surrounding the plant, such as the soil around the seed or growth medium in a hydroponics arrangement for growing plants.

Optionally, the amount of rosin is 0.1-50 wt-% of the total weight of the composition. The amount of rosin may be from 0.1, 0.3, 0.5, 1, 1.5, 2,

2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10, 10.5, 11,

11.5, 12, 12.5, 13, 13.5, 14, 14.5, 15, 15.5, 16, 16.5, 17, 17.5, 18,

18.5, 19, 19.5, 20, 20.5, 21, 21.5, 22, 22.5, 23, 23.5, 24, 24.5, 25,

25.5, 26, 26.5, 27, 27.5, 28, 28.5, 29, 29.5, 30, 30.5, 31, 31.5, 32,

32.5, 33, 33.5, 34, 34.5, 35, 35.5, 36, 36.5, 37, 37.5, 38, 38.5, 39,

39.5, 40, 40.5, 41, 41.5, 42, 42.5, 43, 43.5, 44, 44.5, 45, 45.5, 46,

46.5, 47, 47.5 or 48 wt-% up to 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5,

5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10, 10.5, 11, 11.5, 12, 12.5, 13,

13.5, 14, 14.5, 15, 15.5, 16, 16.5, 17, 17.5, 18, 18.5, 19, 19.5, 20,

20.5, 21, 21.5, 22, 22.5, 23, 23.5, 24, 24.5, 25, 25.5, 26, 26.5, 27,

27.5, 28, 28.5, 29, 29.5, 30, 30.5, 31, 31.5, 32, 32.5, 33, 33.5, 34,

34.5, 35, 35.5, 36, 36.5, 37, 37.5, 38, 38.5, 39, 39.5, 40, 40.5, 41,

41.5, 42, 42.5, 43, 43.5, 44, 44.5, 45, 45.5, 46, 46.5, 47, 47.5, 48.5, 49, 49.5 or 50 wt-%. More optionally, the amount of rosin is 5-25 wt- % of the total weight of the composition. The amount of rosin may be from 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10, 10.5, 11, 11.5, 12, 12.5, 13, 13.5, 14, 14.5, 15, 15.5, 16, 16.5, 17, 17.5, 18, 18.5, 19, 19.5, 20,

20.5, 21, 21.5, 22, 22.5, 23, 23.5 or 24 wt-% up to 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10, 10.5, 11, 11.5, 12, 12.5, 13, 13.5, 14, 14.5, 15, 15.5, 16, 16.5, 17, 17.5, 18, 18.5, 19, 19.5, 20, 20.5, 21, 21.5, 22, 22.5, 23,

23.5, 24.5 or 25 wt-%. It will be appreciated that higher concentrations of rosin provide enhanced protection to the plant as compared to lower concentrations of rosin. However, such higher concentrations of the rosin may lead to increased precipitation during sample preparation, and may thus result in formation of larger precipitates.

In a further aspect, an embodiment of the present disclosure provides a composition comprising rosin, in particular an alkali salt of rosin, and at least one solvent, such as alcohol, wherein the amount of rosin is 0.5-5 wt-% of the total weight of the composition, such as for example 1-3 wt% of the total weight of the composition.

In an example, the amount of rosin may be 1-3 wt-% of the total weight of the composition. In such a case, limiting the concentration of rosin to 1-3 wt-% of the total weight of the composition results in lower precipitation of rosin and enables effective antimicrobial activity of the rosin. It will be appreciated that rosin at a concentration of 3 wt-% is more effective in protecting the seeds as compared to rosin used at a concentration of 1 wt-% of the total weight of the composition, while bearing in mind that for some applications, 1 wt-% may be fully sufficient as a preferable amount of rosin.

In an embodiment of the invention, the rosin comprises or consists essentially of abietic acid, dehydroabietic acid, palustric acid, isopimaric acid, pimaric acid, dihydroabietics acid, neoabietic acid, 13-b-7,9(11)- abietic acid, 8.12-abietic acid, 7,9(l l)-abietic acid, sandaracopimaric acid, 8,15-pimaric acid, 8,15-isopimaradien-18-oic acid, levopimaric acid and combinations thereof. In a further embodiment of the invention, the rosin comprises at least 38 wt-% abietic acid, typically at least 40 wt-% abietic acid, and at least 15 wt-% dehydroabietic acid, based on the total weight of the rosin.

In a still further embodiment of the invention, the rosin comprises 38- 45 wt-% abietic acid, 15-22 wt-% dehydroabietic acid, 8-12 wt-% palustric acid, possibly with 3-5 wt-% isopimaric acid, 3-5 wt-% pimaric acid, 3-5 wt-% dihydroabietics acid (group), and 3-5 wt-% neoabietic acid, based on the total weight of the rosin, and further optionally with minor amounts of other abietic acids or pimaric acids.

Optionally, the at least one solvent is at least one alcohol. It will be appreciated that presence of free rosin or its derivatives that are insoluble or partly soluble in water generates the need for use of the at least one alcohol. Specifically, the at least one alcohol enables increased solubility of the rosin. More optionally, the at least one alcohol is selected from ethanol and isopropanol. It may also be a mixture of ethanol and isopropanol, at various ratios, such as comprising ethanol and isopropanol. Furthermore, ethanol, isopropanol and/or combination thereof are safe to be sprayed on plants or any part thereof, such as seeds. In some embodiments, the at least one alcohol may, in addition to those mentioned above, be selected from dimethyl sulfoxide, propylene glycol, glycerol, other polyalcohols, and their combinations.

Furthermore optionally, the alcohol is used at a concentration of 5-70 wt-%. It will be appreciated that the composition comprising rosin and at least one solvent, such as at least one alcohol, can be used for seed treatment in a concentrated or a diluted form. The weight percentage of rosin and the at least one alcohol is in a range of 0.5-50 wt-%, more preferably 5-25 wt-%, and 5-70 wt-% of the total weight of the composition. In an example, the amount of at least one alcohol may be from 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10, 10.5, 11, 11.5, 12, 12.5,

13, 13.5, 14, 14.5, 15, 15.5, 16, 16.5, 17, 17.5, 18, 18.5, 19, 19.5, 20,

20.5, 21, 21.5, 22, 22.5, 23, 23.5, 24, 24.5, 25, 25.5, 26, 26.5, 27,

27.5, 28, 28.5, 29, 29.5, 30, 30.5, 31, 31.5, 32, 32.5, 33, 33.5, 34,

34.5, 35, 35.5, 36, 36.5, 37, 37.5, 38, 38.5, 39, 39.5, 40, 40.5, 41,

41.5, 42, 42.5, 43, 43.5, 44, 44.5, 45, 45.5, 46, 46.5, 47, 47.5, 48,

48.5, 49, 49.5, 50, 55.5, 56, 56.5, 57, 57.5, 58, 58.5, 59, 59.5, 60,

60.5, 61, 61.5, 62, 62.5, 63, 63.5, 64, 64.5 or 65 wt-% up to 10, 10.5,

11, 11.5, 12, 12.5, 13, 13.5, 14, 14.5, 15, 15.5, 16, 16.5, 17, 17.5, 18,

18.5, 19, 19.5, 20, 20.5, 21, 21.5, 22, 22.5, 23, 23.5, 24, 24.5, 25,

25.5, 26, 26.5, 27, 27.5, 28, 28.5, 29, 29.5, 30, 30.5, 31, 31.5, 32,

32.5, 33, 33.5, 34, 34.5, 35, 35.5, 36, 36.5, 37, 37.5, 38, 38.5, 39,

39.5, 40, 40.5, 41, 41.5, 42, 42.5, 43, 43.5, 44, 44.5, 45, 45.5, 46,

46.5, 47, 47.5, 48, 48.5, 49, 49.5, 50, 55.5, 56, 56.5, 57, 57.5, 58,

58.5, 59, 59.5, 60, 60.5, 61, 61.5, 62, 62.5, 63, 63.5, 64, 64.5, 65.5, 66, 66.5, 67, 67.5, 68, 68.5, 69, 69.5 or 70 wt-% of the total weight of the composition.

Optionally, other components can be added to the composition. More optionally, the other components (or additives) are added to alter a natural composition of ethanol, isopropanol and/or combination thereof, thereby making it more appropriate for use as a solvent. Furthermore, the other components can be added to improve the solubility of the composition. However, it is not desirable to use additives that could also impact growth of plants and/or pathogens on the plants (such as additives that promote growth of pathogens on plants). In addition to an increase in cost of the composition after addition of such other components or additives, repeated use is likely to impact plant growth and/or aggravate harmful environmental interactions, such as promote a harmful change in the atmospheric carbon dioxide concentration around the plants. Some suitable additives can be for example surface active agents (for example up to 20 wt-%), agents modifying the viscosity of the composition, such as carboxy methyl cellulose and its derivatives (for example up to 20 wt-%), agents modifying the adsorption of the composition (for example up to 30 wt-%). Further examples of suitable additives include but are not limited to wetter-spreaders, stickers, emulsifiable oil activators, foliar nutrients, compatibility agents, drift retardants, foam retardants, buffers, plant penetrants, inverting agents, sinking agents, protectant binders, and stabilizing agents, each for example up to 20 wt-%. A person skilled in the art is to able select a suitable additive depending on other components of the composition.

Optionally, pH of the composition is 3-12. It will be appreciated that dissolution of rosin in at least one solvent is subjective to the pH of the solvent. The pH has an effect on the solubility of the sodium salt of rosin into aqueous solutions. Indeed, when the sodium salt of rosin is dissolved in water, its pH is about 10-11. If the pH is lowered (for example by adding hydrochloric acid) to 7.5-8.5, the rosin precipitates. Thereafter, it reacts to form its free acid form, alcohol increasing the solubility. Furthermore, at a pH of 8, the rosin dissolves completely in the at least one alcohol. It is desirable that pH of the composition is adjusted to about 8 with the addition of a suitable acid or base. A suitable acid or base includes, but is not limited to, 1 molar (1M) sodium hydroxide (NaOH) or 1M hydrochloric acid (HCI), respectively. However, addition of such acids results in formation of precipitates in higher concentrations of the composition. The precipitation may impact the actual concentration of rosin in the total composition, thereby impacting (such as reducing) the growth of pathogens. The pH of the composition can thus be for example from 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10 or 10.5, 11, 11.5 up to 4, 4.5, 5, 5.5, 6, 6.5, 7, 8, 8.5, 9, 9.5, 10, 10.5, 11, 11.5 or 12.

The present disclosure also provides the method of treating seeds. The method comprises providing a solution of rosin and at least one solvent. Optionally, a commercially available solid tail-oil rosin (Forchem for90) is dissolved into the at least one solvent, preferably at least one alcohol, more preferably the at least one alcohol selected from ethanol and isopropanol. More optionally, the amount of rosin is 0.1-50 wt-% of the total weight of the composition. Furthermore optionally, the concentration of Forchem (For90) is 0.51-50 wt-%, more preferably at 5-25 wt-% of the total weight of the composition. The various embodiments and possible concentrations as given above in connection with the use apply mutatis mutandis to the method.

Moreover, the concentration is provided to be applied externally to the seeds. Optionally, the at least one solvent used for dissolving the rosin can be selected from ethanol, isopropanol or a combination thereof. In some embodiments, the at least one solvent can also be selected from dimethyl sulfoxide, propylene glycol, glycerol, other polyalcohols, and their combinations, in addition to those mentioned above, Furthermore, the method comprises providing a solution of rosin and the at least one solvent and subsequently, spraying the solution on the seeds. The seeds are sprayed with the provided solution of rosin and the at least one solvent in a predefined concentration. Notably, spraying at least one of alcohols, selected from ethanol, isopropanol and/or combination thereof, even at substantially higher concentrations, is safer than watering plants with even low concentrations of ethanol, isopropanol and/or combination thereof. For example, spraying ethanol at a concentration of up to 70 % may not cause damage to the plant, while watering the plant even with a concentration ranging between 5- 25 % of ethanol may result in stressing (at 5 % concentration of ethanol) or death (at 25 % concentration of ethanol) of the plant.

Alternatively, the external application of the composition to the seeds comprises wetting, watering or brushing the seeds with the composition.

Furthermore, the method comprises drying the sprayed seeds. The sprayed seeds are dried to evaporate the at least one alcohol from the provided solution of the rosin and the at least one solvent. Notably, with the evaporation of the at least one solvent, the water-insoluble free acid form of rosin forms a protective coating around the seed, which acts as an antifungal agent for the seeds. Furthermore, the water-soluble alkali metal salt of rosin is absorbed in the surrounding ground or soil around the seed. Beneficially, the alkali metal salt of rosin act as an antifungal agent for the soil surrounding the seed. Moreover, the use of the composition comprising rosin and at least one solvent for seed treatment and method thereof protects the seeds from the harmful effects of the pathogens such as fungi as well as the at least one solvent, such as the aforementioned organic solvents.

In an exemplary implementation, the composition comprising rosin and at least one alcohol is used for seed treatment. Flowever, the composition may also be used as potential fungicide, bactericide and so forth, owing to the antimicrobial properties of the rosin and the disinfectant properties of the at least one alcohol. Specifically, the composition is applied externally to the seeds. More specifically, the application is for example by way of spraying, wetting, watering or brushing the seeds with the composition. Spraying the seeds with the composition typically protects the seeds from the harmful effects of alcohol on the plants as alcohol evaporates over a period of time, leaving behind a protective coating of the rosin over the seed. Furthermore, along with the antifungal effects of the composition, the pH of 7.5-8.5 protects the seeds from a potential attack from the different species of fungi in the environment (such as ground). Furthermore, the composition comprising both the forms of rosin, i.e. the free rosin acid and the sodium salt of rosin provides protection to the seeds and fungicidal effect on the surrounding ground (soil or water, such as in hydroponics arrangement for plant growth) respectively.

EXPERIMENTAL PART

The rosin was tested in seed treatment as follows. A mixture of free rosin acid (For90) and ethanol comprising 20 wt-% of free rosin acid was sprayed on oat seeds and the ethanol was allowed to evaporate. A shiny, dense coating was formed on the surface of the seeds, after evaporation of ethanol. Thereafter, the seeds were allowed to germinate. The thus treated seeds were compared to untreated seeds, and both germinated in identical manner. Thus the seed treatment did not affect the germination of the seeds.

Moreover, the antifungal properties of the composition were used for preventing growth of fungus on the plants. In this regard, different species of fungi were grown in potato dextrose agar (indicated as 'PDA' hereafter) powder (comprising agar and nutrients for growth of fungi) for a period of 4 days at a temperature of +18°C. The cultured species of the fungi having a diameter of 7 mm or more were inoculated and their growth was monitored in a sample comprising dried form of rosin, optionally the sodium salt of rosin, and PDA. Such sample of rosin and PDA was dissolved in cold water and pH of the resulting mixture was adjusted to about 8, by adding a suitable acid or a base thereto. Furthermore, the resulting first sample was heated in an autoclave maintained at a predefined temperature of 121 °C. It was observed that, at such a high temperature the precipitates formed in the composition had ceased to exist. However, the precipitation in the composition continued to occur at room temperature (about 20 °C).

In one test, the fungus was selected from a group comprising Botrytis cinerea, Pyrenophora teres, Bipolaris sorokiniana, Stagonospora nodorum, Fusarium graminearum and Fusarium avenaceum . It will be appreciated that other species of fungi having similar characteristics including, but not limiting to, colour, formation of spores, structure and density, may also be selected. The six species of fungi were grown under dark conditions at +18 °C and at 3 different concentrations of rosin, i.e. 0 wt-% (i.e. absence of the rosin in the first sample or "control"), 1 wt-% and 3 wt-%. Subsequently, the average growth of fungi was recorded for a period of 4, 8 and 14 days after anthesis (DAA) at each concentration. The different concentrations of the rosin were used to test the effect of the rosin on the growth of fungi. It was observed that presence of rosin had a significant impact on the growth of all the aforementioned species of fungi. Moreover, the stronger concentration i.e. 3 wt-% concentration of rosin prohibited the growth of fungal species Pyrenophora teres, Bipolaris sorokiniana, Stagonospora nodorum and Fusarium graminearum until the 8 ^th day and 14 ^th day. However, the fast-growing species of fungi, namely, Botrytis cinerea and Fusarium avenaceum, also demonstrated a significant reduction in growth at 3 wt-% concentration of rosin. Notably, even at 1 wt-% concentration of rosin, the growth of fungi was significantly reduced or substantially prohibited for all the aforementioned species of fungi. Furthermore, higher concentrations of rosin had an effect on weakening the spreading and conservation of the aforementioned species of the fungi.

It will be appreciated that the rosin has an impact not only to reduce the growth of the fungi, but also in modifying structure and formation of spores of some species of fungi. In an example, based on a visual study, the growth of fungus Fusarium gram inearum was abundant and lint-like in the control sample, while in the sample with rosin, the growth of the fungi was dense and observed to be located only at the surface of the sample. In another example, fungus Botrytis cinerea formed several sclerotium in the control sample, while the presence of rosin prohibited the formation of sclerotium until the 8 ^th day and 14 ^th day. However, the formation of sclerotium was observed after the 14 ^th day at the 1 wt-% concentration of rosin.

Moreover, colour of some species of the fungi may be a measure of the growth of fungi in a sample. In an example, the fungus Bipolaris sorokiniana exhibited black spots containing a significant number of conidium, while in the samples comprising rosin at any concentration, the fungal growth was lighter in colour and contained no or negligible conidium. Furthermore, presence of the rosin significantly limited the formation of spores in fungal species, such as Pyrenophora teres, Stagonospora nodorum and Fusarium avenaceum .

The test results are shown in FIGs. 1A, IB and 1C, as graphical representations of average growth of fungi. The different species of fungi were grown in different concentrations of compositions under dark conditions, as explained above, for a predefined period of time. As shown, the Y-axis (vertical axis) of the graphs represent the average growth of fungi in millimetres (mm). The X-axis (horizontal axis) of the graphs represent the different species of fungi Botrytis cinerea (depicted as species code ' ), Pyrenophora teres (depicted as '2'), Bipolaris sorokiniana (depicted as '3'), Stagonospora nodorum (depicted as '4'), Fusarium graminearum (depicted as '5') and Fusarium avenaceum (depicted as '6'). In each FIG., for each species of fungi, the left-most column is the result at 4 days, the middle column is the result at 8 days and the right-most column the result at 14 days. The same applies for FIG. 1A to 1C. As shown in FIG. 1A, the different species of fungi grew normally under control conditions, i.e. when the concentration of rosin was 0 wt-%. However, addition of rosin in each sample of fungi resulted in a significant impact on the growth of fungus, as shown in FIGs. IB and 1C. At the concentration of 3 wt-%, rosin prohibited the growth of all species of fungi until 8 days and 14 days. Moreover, only the fastest growing species of fungi, such as Botrytis cinereal and Fusarium avenaceum were able to grow despite the stronger concentration of rosin. In another exemplary implementation, four species of fungi, namely, Botrytis cinereal, Pyrenophora teres, Bipolaris sorokiniana and Fusarium avenaceum, were grown at +18°C and at five different concentrations of rosin. Furthermore, the different species of fungi were grown by exposure to near visible ultraviolet (NUV) light for 12 hours per day and the growth of fungi was measured at the 3 ^rd day and the 6 ^th day of culture. It was observed that presence of rosin had a significant impact on the growth of all the four species of fungi. Furthermore, even the lower concentrations of 0.5 wt-% or 1 wt-% had a significant impact on the growth, when compared to the control sample (0 wt-%). However, the growth of fungi could not be significantly observed at higher concentrations, i.e. 2 wt-% and 3 wt-% of the rosin, due to the precipitation of the rosin at such concentrations.

The results are shown in FIGs. 2A to 2E as graphical representations. As shown the Y-axis (vertical axis) of the graphs represent the average growth of fungi in millimetres (mm). The X-axis (horizontal axis) of the graphs represent the different species of fungi, namely Botrytis cinerea (depicted as species code ' ), Pyrenophora teres (depicted as '2'), Bipolaris sorokiniana (depicted as '3') and Fusarium avenaceum (depicted as '6'). The average growth of fungi was recorded for a period of 3 and 6 days after anthesis (DAA) at each concentration of 0 wt-%, 0.5 wt-%, 1 wt-%, 2 wt-% and 3 wt-% of rosin as shown in FIG. 2A, FIG. 2B, FIG. 2C, FIG. 2D and FIG. 2E respectively. In each FIG., for each species of fungi, the left column is the result at 3 days and the right column the result at 6 days. FIG. 2A shows that the different species of fungi grew normally under control conditions, i.e. when the concentration of rosin is 0 wt-%. Flowever, addition of rosin in each sample of fungi resulted in a significant impact on the growth of fungus, as shown in FIGs. 2B to 2E. At the concentration of 0.5 wt-% and 1 wt-%, presence of rosin substantially reduced the growth of all species of fungi as compared to the control. Moreover, the differences between the samples at higher concentrations, i.e. 2 wt-% and 3 wt-%, prohibited the growth of some species of fungi until 3 days, however, at the end of 6 days, due to precipitation of rosin at higher concentrations, the reduction in growth of such fungi was substantially impacted.

FIELD TRIALS

The antifungal properties of the composition were tested in field trials by evaluating germination and protection against plant pathogenic fungi when seeds of spring barley (2 varieties), spring wheat and common oat (2 varieties) had been treated with the compositions of the invention prior sowing.

The compositions tested contained varying amounts of the sodium salt of rosin acid in either water (A) or 96% ethanol (B). Water and 96% ethanol were used as reference compositions. In addition, untreated seeds were included in the study as controls. The numbering of the treatments and the amounts of active ingredient (sodium salt of rosin acid) per seed weight were as follows: Table 1 . Numbering of treatments

*The amount was adjusted to the volume needed for the preparation of an appropriate solution of active agent of a 17-18% stock solution for products A and B. Trials were sown on 9 ^th and 17 ^th of May. Growth and efficacy against pathogenic fungi were followed until the end of July when plant stands started to ripen. Observations were collected from four replicate plots per treatment per trial. Yield quantity and quality will be calculated after harvesting. Emerged plants were calculated twice, first 11-12 days after sowing and subsequently 21-32 days after sowing. Plants with leaf spot symptoms were counted at the second observation. Root diseases ( Fusarium sp ) were observed 39-47 days after sowing. Plants were dug up and disease damages were scored (healthy, mild symptoms, severe symptoms). Leaf blotch, net blotch or leaf stripe of the plants ( Pyrenophora sp ) were also evaluated again from the plant samples. Heads with smut ( Ustilago sp) symptoms were counted per plot and plants with leaf stripe symptoms were counted from 1.5 m ² area. The results are summarized in Table 2.

Table 2 . Summary of results from field trials

The results indicate that Product A does not adversely affect germination and does not cause any other detectable phytotoxic symptoms. As expected, ethanol-based product B tended to slightly decrease the number of emerged plants, particularly in case of wheat which has a very soft outer shell compared to barley and oat. However, the number of emerged plants of one of the two tested barley varieties surprisingly increased. Due to the weather conditions that prevailed during the field trials (extremely dry conditions during early summer), no significant effect against foot rot was seen in any of the treatments.

Ethanol-based products were effective against net blotch and leaf stripe of barley. The highest concentration of water-based product A had a remarkable effect on leaf stripe of barley compared to the untreated or water-treated seeds. It also provided slightly better effect against leaf blotch of oat than ethanol-based products. Results for both varieties of barley are summarized in Table 3. Table 3 . Results for barley

The effect on leaf stripe of barley is further illustrated in Figu re 4 , wherein the results obtained by different concentrations of Product A compared to untreated seeds (1) or water-treated seeds (2) in preventing leaf stripe of barley are shown. As can be seen from Fig. 4, the composition of the invention has an antifungal effect, which increases with increasing dose of rosin.

Ethanol-based products were effective against smut fungi. All concentrations of Product A reduced heads with smut symptoms in oat when compared to untreated or water-treated seeds, the highest concentration of product A having a significant impact. Ethanol-based products were also effective against smut fungi in oat, as can be seen in Table 4. Table 4. Results for oat

The effect against smut fungi in oat is further illustrated in Figu re 5 , wherein the results obtained by different concentrations of Product A compared to untreated seeds (1) or water-treated seeds (2) in preventing heads with smut in oats are shown. As can be seen from Fig. 5, the composition of the invention has an effect against formation of heads with smut, and the effect increases with increasing dose of the active agent. Notably, even at low concentrations of rosin, such as 0.75% or 1%, based on the weight of the seeds, the growth of fungi and the formation of head smuts was significantly reduced or substantially prohibited also in field trials, even without optimizing the composition and without suitable additives, such as agents modifying the adsorption of the composition, which may further advance achieving the desired antimicrobial, in particular antifungal effects.

DETAILED DESCRIPTION OF THE DRAWINGS

Referring to FIG. 3, there are shown steps of a method 300 of treating seeds, in accordance with an embodiment of the present disclosure. At step 302 , a solution of rosin and at least one solvent is provided. At step 304 , the solution is sprayed on the seeds. At step 306 , the seeds sprayed with the solution are dried.

The steps 302 to 306 are only illustrative and other alternatives can also be provided where one or more steps are added, one or more steps are removed, or one or more steps are provided in a different sequence without departing from the scope of the claims herein.

Modifications to embodiments of the present disclosure described in the foregoing are possible without departing from the scope of the present disclosure as defined by the accompanying claims. Expressions such as "including", "comprising", "incorporating", "have", "is" used to describe and claim the present disclosure are intended to be construed in a non exclusive manner, namely allowing for items, components or elements not explicitly described also to be present. Reference to the singular is also to be construed to relate to the plural.

CITATION LIST

EA 027877 B1 CN 106259564 A Arruda, G.O.S. F. DE et al. Ciencia Florestal 2007, Vol. 18, No. 1/2, pp 75-84, ISSN 0103-9954