TECHNICAL FIELD

The present subject matter relates to a method for controlling Spongospora subterranean (Powdery scab) in seeds, tubers, a plant grown from the seed or a plant grown from the tubers.

BACKGROUND

Dimethomorph is a systemic fungicide which protects plants from fungi in the water mold family (Oomycetes), such as late blight and downy mildew. Dimethomorph moves up the treated plant stem and into growing leaves. It also has anti-sporulant activity which helps to prevent the spread of blight between plants. The mode of action of dimethomorph is that it affects cell wall production in fungi by inhibition of sterol synthesis.

Fluazinam is a broad spectrum contact fungicide that can be applied as a foliar spray or soil treatment. It is effective against a number of pathogenic fungi that cause the following diseases: foliar blight, tuber blight and sclerotinia rot in potatoes caused by the fungus Phytophthora infestans. Fluazinam is effective against both spore germination and spore growth, thereby giving it protective action with a good residual effect. The mode of action of fluazinam is due to the disruption of energy production in the fungus at multiple sites, therefore preventing resistance.

EP 0956769 teaches a liquid concentrated fungicidal composition comprising a fungicidally acceptable carrier and/or surface active agent and synergistically effective amounts of an acrylic acid morpholide and a at least one fungicidal N-pyridylaniline compound. The composition is to be used for controlling diseases caused by oomycetes, e.g. Phytophthora infestans.

Powdery scab is a disease of potato tubers. It is caused by the cercozoan Spongospora subterranea f. sp. subterranea and is widespread in potato growing countries. Symptoms of powdery scab include small lesions in the early stages of the disease, progressing to raised pustules containing a powdery mass. Powdery scab has a cosmetic effect on tubers, which can result in rejection of potatoes. The powdery pustules contain resting spores, which release zoospores which can infect the root hairs of potatoes or tomatoes. Powdery scab is both seed and soil borne. Incidence and severity of powdery scab symptoms can vary widely depending on a range of factors, including inoculum level and climatic conditions. Sporadic occurrences can have a big effect on crop value. It can result in total rejection of fresh crop if severe for example, and can have big consequences for peeling before processing.

Clubroot of cabbage and related crucifers is caused by the soilborne protist Plasmodiophora brassicae. Plasmodiophora brassicae forms no mycelia and can develop and multiply only in living host cells. The disease causes the formation of large galls on the roots which look like clubs. These formations impede nutrient and water uptake and can cause plant death. The pathogen can survive in a field for years as resting spores without a host present and will infect the next crop planted if it is a susceptible host.

As such, means have been sought to control powdery scab and clubroot infections by a treatment of plants using agricultural fungicides. Generally, agricultural fungicides are chemical compounds used to kill or inhibit fungi or fungal spores. Agricultural fungicides can be used to protect seed grain during storage, shipment and germination and to protect mature crops, berries, seedlings, flowers and grasses in the field, in storage and during shipment. They can be applied to the soil to control fungi that are resident there, to the seed or foliage of the plant to be protected, or to harvested produce to prevent storage losses.

Therefore, there is still a need for a fungicide composition that demonstrates a synergistic effect of inhibiting the growth of protists from the class of Phytomyxea.

Combinations of agricultural fungicides are typically used to broaden the spectrum of control, to minimize the doses of chemicals used and to reduce the cost of the treatment through additive effect. Combinations of agricultural fungicides can be also used to avoid or delay the risk of resistance development.

Synergism has been defined as the simultaneous action of two or more compounds in which the total response of an organism to the pesticide combination is greater than the sum of the individual components. Although many combinations of fungicides have been studied, a synergistic effect is rarely revealed and the global use of fungicide combinations with synergistically enhanced activity is rather limited. SUMMARY

The subject matter relates to a method of controlling growth of a protist from the class Phytomyxea in seeds, tubers, a plant grown from the seed, or a plant grown from the tubers by contacting the seeds, the plants or soil in which the seeds or tubers are planted with a synergistically effective amount of a combination of a morpholine fungicide and a pyridine fungicide.

Another embodiment relates to a use of a composition comprising a synergistic combination of a morpholine fungicide and a pyridine fungicide for controlling growth of a protist from the class Phytomyxea in seeds, tubers, a plant grown from the seed, or a plant grown from the tubers.

Another embodiment relates to a fungicidal composition comprising a synergistic combination of a morpholine fungicide and a pyridine fungicide for use in controlling growth of a protist from the class Phytomyxea in seeds, tubers, a plant grown from the seed, or a plant grown from the tubers. The composition may further comprise an agriculturally acceptable carrier. In some embodiments, the composition may further comprise at least one surfactant, solid diluent, liquid diluent, or a combination thereof.

In an embodiment, the protist may be at least one of Spongospora subterranean and Plasmodiophora brassicae. The morpholine fungicide may be dimethomorph and the pyridine fungicide may be fluazinam.

In some embodiments, the ratio by weight of the morpholine fungicide to the pyridine fungicide may be from approximately 1: 10 to approximately 10: 1. In some further embodiments, the ratio by weight of the morpholine fungicide to the pyridine fungicide may be 1: 1. The application rates of the combination of the combination may be from approximately 1000 g/ha to approximately 2500 g/ha. In a further embodiment, the combination may be from approximately 1500 g/ha to approximately 2000 g/ha.

DETAILED DESCRIPTION

Definitions

All technical and scientific terms used herein have the same meanings as commonly understood by someone ordinarily skilled in the art to which the present subject matter belongs. The following definitions are provided for clarity. The term "adjuvant," as used herein, refers to a substance, which can increase the biological activity of an active ingredient, but is not itself significantly biologically active.

The term "contacting," as used herein, refers to applying the compounds and compositions described herein to the plant, to a site of infestation by protists, to a potential site of infestation by protists, which may require protection from infestation, or the environment around the habitat or potential habitat of protists. The application may be by methods according to the present subject matter, such as by spraying, dipping, etc.

The term "ha," as used herein, refers to hectare.

The term "plant," as used herein, refers to whole plants, plant organs (e.g. leaves, stems, twigs, roots, trunks, limbs, shoots, fruits etc.), or plant cells. This term also encompasses plant crops such as fruits. In one embodiment, the term "plant" may include the propagation material thereof, which may include seeds and spores, vegetative structures such as bulbs, corms, tubers, rhizomes, roots stems, basal shoots, stolons, and buds. In another embodiment, the plants include vegetables, such as potatoes and tomatoes. In still another embodiment, plants that tolerate the action of herbicides, fungicides or insecticides as a result of breeding, mutagenesis or genetic engineering methods are also included.

The term "surfactant," as used herein, refers to an agriculturally acceptable material which imparts emulsifiability, stability, spreading, wetting, dispersibility or other surface-modifying properties.

The term "a" or "an" as used herein includes the singular and the plural, unless specifically stated otherwise. Therefore, the term "a," "an," or "at least one" can be used interchangeably in this application.

Throughout the application, descriptions of various embodiments use the term "comprising;" however, it will be understood by one of skill in the art, that in some specific instances, an embodiment can alternatively be described using the language "consisting essentially of or "consisting of."

For the purposes of better understanding the present teachings and in no way limiting the scope of the teachings, unless otherwise indicated, all numbers expressing quantities, percentages or proportions, and other numerical values used in the specification and claims, are to be understood as being modified in all instances by the term "about." Accordingly, unless indicated to the contrary, the numerical parameters set forth in the following specification and attached claims are approximations that may vary depending upon the desired properties sought to be obtained. At the very least, each numerical parameter should at least be construed in light of the number of reported significant digits and by applying ordinary rounding techniques.

It has been found that the combination of a morpholine fungicide such as dimethomorph and a pyridine fungicide such as fluazinam results in a synergistic fungicidal activity against the growth of protists from the class Phytomyxea. In some embodiments, the protists may include Spongospora subterranean and Plasmodiophora brassicae. The combination provides a higher fungicidal activity than that envisaged on the basis of the sum of activities of each of the fungicides found therein. Such a combination allows the reduced dosages of the individual fungicides which can damage agriculturally important plants.

In yet another embodiment, the morpholine fungicides include compounds such as aldimorph, benzamorf, carbamorph, dimethomorph, dodemorph and salts thereof, fenpropimorph, flumorph, and tridemorph or a combination comprising at least one of the foregoing. In one representative embodiment, the morpholine fungicide is dimethomorph.

In another embodiment, the pyridine fungicides include compounds such as boscalid, buthiobate, dipyrithione, fluazinam, fluopicolide, fluopyram, parinol, picarbutrazox, pyribencarb, pyridinitril, pyrifenox, pyrisoxazole, pyroxychlor, pyroxyfur, triclopyricarb or a combination comprising at least one of the foregoing. In an embodiment of the present subject matter, the pyridine fungicide is fluazinam.

In another embodiment, the ratio (by weight) of the morpholine fungicide to the pyridine fungicide is from 1: 100 to 100: 1. In another embodiment the ratio is from 1:25 to 25: 1. In a further embodiment the ratio is from 1: 10 to 10: 1. In a specific embodiment, the ratio (by weight) of the morpholine fungicide to the pyridine fungicide is 1: 1.

In an embodiment, a method for controlling and/or preventing the growth of protists from the class Phytomyxea in seeds, tubers, a plant grown from the seed, or a plant grown from the tubers, which comprises contacting the seeds, the plants or soil in which the seeds or tubers are planted with a synergistically effective amount of a combination of a morpholine fungicide and a pyridine fungicide, is provided.

For example, a method for controlling and/or preventing a disease caused by Spongospora subterranea f.sp. Subterranea in seeds, tubers, a plant grown from the seed, or a plant grown from the tubers by contacting the seeds, tubers, the plants grown from the seeds or tuber or the soil in which the seeds or tubers are planted, with a synergistically effective amount of dimethomorph and fluazinam, is provided.

In another embodiment, the use of a composition comprising a synergistic combination of a morpholine fungicide and a pyridine fungicide for controlling and/or preventing growth of a protist from the class Phytomyxea in seeds, tubers, a plant grown from the seed, or a plant grown from the tubers, is provided.

For example, use of a composition comprising a synergistically effective amount of dimethomorph and fluazinam for controlling and/or preventing a disease caused by Spongospora subterranea f.sp. Subterranea in seeds, tubers, a plant grown from the seed, or a plant grown from the tubers, is provided.

In another embodiment, the protists may be one or more of the class phytomyxea. In some examples, this may include Spongospora subterranea f.sp. Subterranea (which causes Powdery scab in potatoes) and Plasmodiophora brassicae (which causes Clubroot in cabbage and other brassicaceous crops).

The application rates of the combination may vary, depending on the desired effect. In an embodiment, depending on the desired effect, the application rates of the mixtures according to the present subject matter may be from approximately 1000 g/ha to 2500 g/ha, particularly from approximately 1500 to 2000 g/ha. In another embodiment, the application rates of the mixtures may be from approximately 1 g/ha to 1000 g/ha, particularly from approximately 100 to 500 g/ha, more particularly from approximately 200 to 400 g/ha.

In a specific embodiment, the application rate of the morpholine fungicide (e.g. dimethomorph) in the mixture may be from approximately 600 g/ha to 1000 g/ha, and the amount of the pyridine fungicide (e.g. fluazinam) in the mixture may be from approximately 600 g/ha to 1000 g/ha. The optimal rate for a specific application of the formulation will depend on the crop and may be readily determined by established biological tests known to those skilled in the art.

The application rates of the combination when used for treating seeds may be from approximately 0.1 to 50 g a.i./kg, and particularly from approximately 1 to 15 g a.i./kg.

According to an embodiment, a fungicidal composition comprising a synergistic combination of a morpholine fungicide and a pyridine fungicide for use in controlling/preventing growth of a protist from the class Phytomyxea in seeds, tubers, a plant grown from the seed, or a plant grown from the tubers, is provided.

In an embodiment, a formulation may be obtained by combining a synergistic amount of the active ingredients with an agriculturally acceptable carrier, a surfactant or other application-promoting adjuvant customarily employed in formulation technology.

The present composition may be employed or prepared in any conventional form, for example, in the form of a twin pack, or for example, as wettable powders (WP), emulsion concentrates (EC), microemulsion concentrates (MEC), water-soluble powders (SP), water-soluble concentrates (SL), suspoemulsion (SE), oil dispersions (OD), concentrated emulsions (BW) such as oil-in-water and water-in-oil emulsions, sprayable solutions or emulsions, capsule suspensions (CS), suspension concentrates (SC), suspension concentrates, dusts (DP), oil-miscible solutions (OL), seed-dressing products, granules (GR) in the form of microgranules, spray granules, coated granules and absorption granules, granules for soil application or broadcasting, water-soluble granules (SG), water-dispersible granules (WDG), ULV formulations, microcapsules or waxes. These individual formulation types are known in the art.

Such compositions can be formulated using agriculturally acceptable carriers, surfactants or other application-promoting adjuvants customarily employed in formulation technology and formulation techniques that are known in the art.

Examples of suitable liquid carriers potentially useful in the present compositions include but are not limited to water; aromatic hydrocarbons such as alkylbenzenes and alkylnaphthalenes; alcohols such as methanol, cyclohexanol, and decanol; ethylene glycol; polypropylene glycol; dipropropylene glycol; N,N- dimethylformamide; dimethylsulfoxide; dimethylacetamide; N-alkylpyrrolidones such as N-methyl-2-pyrrolidone; paraffins; various oils such as olive, castor, linseed, tung, sesame, corn, peanut, cotton-seed, soybean, rape-seed, or coconut oil; fatty acid esters; ketones such as cyclohexanone, 2-heptanone, isophorone, and 4-hydroxy-4-methyl-2- pentanone; and the like.

Examples of suitable solid carriers potentially useful in the present compositions include but are not limited to mineral earths such as silica gels, silicates, talc, kaolin, sericite, attaclay, limestone, bentonite, lime, chalk, bole, mirabilite, loess, clay, dolomite, zeolite, diatomaceous earth, calcium carbonate, calcium sulfate, magnesium sulfate, magnesium oxide, sodium carbonate and bicarbonate, and sodium sulfate; ground synthetic materials; fertilizers such as ammonium sulfate, ammonium phosphate, ammonium nitrate, ureas, and products of vegetable origin, such as cereal meal, tree bark meal, wood meal, and nutshell meal; cellulose powders; and other solid carriers.

Examples of suitable surfactants include, but are not limited to, non-ionic, anionic, cationic and ampholytic types such as alkoxylated fatty alcohols, ethoxylated polysorbate (e.g. tween 20), ethoxylated castor oil, lignin sulfonates, fatty acid sulfonates (e.g. lauryl sulfonate), phosphate esters such as phosphate esters of alcohol alkoxylates, phosphate esters of alkylphenol alkoxylates and phosphate esters of styrylphenol ethoxylates, condensates of sulfonated naphthalene and naphthalene derivatives with formaldehyde, condensates of naphthalene or of naphthalene sulfonic acid with phenol and formaldehyde, alkylarylsulfonates, ethoxylated alkylphenols and aryl phenols, polyalkylene glycols, sorbitol esters, alkali metal, sodium salts of lignosulphonates, tristyrylphenol ethoxylate phosphate esters, aliphatic alcohol ethoxylates, alkylphenol ethoxylates, ethylene oxide/propylene oxide block copolymers, graft copolymers and polyvinyl alcohol- vinyl acetate copolymers. Other surfactants known in the art may be used as desired.

The biological activity of the active ingredient can also be increased by including an adjuvant to the composition. Other ingredients, such as wetting agents, anti-foaming agents, adhesives, thickeners, binders, fertilizers, biocides, stabilizers, buffers, or anti-freeze agents, may also be added to the composition including the combination of the fungicides in order to increase the stability, density and viscosity of the composition. In an embodiment, the amount of the active ingredient or ingredients in the composition is about 0.1-99 wt. %, about 0.1-95 wt. %, or about 0.1-90 wt. %, based on the total weight of the composition. In another embodiment, the amount of the mixture of active ingredients in the composition is about 10-90 wt. %. In a further embodiment, the amount of the mixture of active ingredients in the composition is about more specifically 10-80 wt. %, based on the total weight of the composition.

As used in the present methods, the herbicidal compositions and herbicidal mixtures discussed herein may be applied jointly or in a succession. That is, each of the morpholine fungicide and a pyridine fungicide may be applied jointly or in succession. In one example, the morpholine fungicide and the pyridine fungicide are prepared separately, and the individual formulations are applied as is, or diluted to predetermined concentrations. In a further example, the morpholine fungicide and the pyridine fungicide are prepared separately, and the formulations are mixed when diluted to a predetermined concentration. In another example, the morpholine fungicide and the pyridine fungicide are formulated together, and the formulation is applied as it is, or the formulation is diluted to a predetermined concentration.

The fungicidal mixture may be applied via basal application, broadcast application, directed- spray application, foliar application, soil application, soil incorporation or soil injection.

The present composition may include additional crop protection agents, for example pesticides, or safeners. However, for the avoidance of doubt it is understood that such additional crop protection agents are unnecessary to achieve the desired control of undesired vegetation as achieved by the present combinations. Accordingly, the present fungicidal compositions and fungicidal mixtures may be limited to containing the combination of a morpholine fungicide and a pyridine fungicide, as the only crop protection agents present.

In another embodiment, the present subject matter provides a kit comprising the fungicidal mixture as described herein, or components thereof. Such kits may comprise, in addition to the aforementioned active ingredients, one or more additional active and/or inactive ingredients, either within the provided fungicidal composition or separately. Certain kits comprise a morpholine fungicide and a pyridine fungicide, each in a separate container, and each optionally combined with a carrier. As noted above, the methods, uses and compositions described herein exhibit a synergistic effect. A synergistic effect exists wherever the action of a combination of active components is greater than the sum of the action of each of the components alone. Therefore, a synergistically effective amount (or an effective amount of a synergistic composition or combination) of the present compositions is an amount that exhibits greater fungicidal activity than the sum of the fungicidal activities of the individual components.

The following examples illustrate the practice of the present subject matter in some of its embodiments, but should not be construed as limiting the scope of the subject matter. Other embodiments will be apparent to one skilled in the art from consideration of the specification and examples. It is intended that the specification, including the examples, is considered exemplary only without limiting the scope and spirit of the subject matter.

EXAMPLES

A synergistic effect exists wherever the action of a combination of active components is greater than the sum of the action of each of the components alone. Therefore, a synergistically effective amount (or an effective amount of a synergistic composition or combination) is an amount that exhibits greater fungicidal activity than the sum of the fungicidal activities of the individual components.

In the field of agriculture, it is often understood that the term "synergy" is as defined by Colby S. R. in an article entitled "Calculation of the synergistic and antagonistic responses of herbicide combinations" published in the journal Weeds, 1967, 15, p. 20-22, incorporated herein by reference in its entirety. The action expected for a given combination of two active components can be calculated as follows:

in which E represents the expected percentage of fungicidal control for the combination of the two fungicides at defined doses (for example equal to x and y respectively), X is the percentage of fungicidal control observed by dimethomorph at a defined dose (equal to x) and Y is the percentage of fungicidal control observed by fluazinam at a defined dose (equal to y). When the percentage of fungicidal control observed for the combination is greater than the expected percentage, there is a synergistic effect. EXAMPLE 1

A trial was conducted in order to estimate the synergistic interaction between dimethomorph and fluazinam in controlling powdery scab, in potatoes.

Commercially available compositions of dimethomorph (Athlete® 50% WG) and Fluazinam (OHAYO® 500 SC), as well as composition comprising a combination of dimethomorph, and fluazinam (mixed at a weight ratio of 1: 1) (Banjo® Forte Dimethomorph 20% and Fluazinam 20% SC) were compared.

Each of the tested compositions were sprayed broadcasting on the beds (i.e. the soil). The soil was incorporated before the potato tubers were planted.

The trial was on potato tubers of the variety Nicola. The fungicidal control of Spongospora subterranea f. sp. Subterranean (Powdery scab) after the application of dimethomorph, fluazinam, and a formulation comprising both dimethomorph as well as fluazinam, was evaluated. The formulations of dimethomorph and fluazinam were individually applied at a rate of 2 L/ha (equivalent to 100 g a.i./ha). The formulation comprising both dimethomorph and fluazinam was applied at rate of 5 L/ha (equivalent to 100 g a.i./ha of each of dimethomorph and fluazinam).

The valuation of the potato tubers were carried out two months after application of the formulations. In order to evaluate the potato tuber and root infection by Spongospora subterranea f. sp. Subterranean, the potatoes were given an index number based on the severity of the infection. A value of 0 was given to potatoes which were not infected. A value of 1 was given to potatoes which had the infection on less than 5% of its surface. A value of 3 was given to potatoes which had the infection on between 5% and 30% of its surface. A value of 5 was given to potatoes which had the infection on more than 30% of its surface. The results are presented in Table 1.

Table 1

Amount of Powdery Scab Infection on Potato Tubers

No

Infection Infection < 5% Infection 5% > 30% Infection > 30%

Control 13.85% 20.51% 32.28% 33.36%

Fluazinam 31.28% 18.73% 32.79% 17.20%

Dimethomorph 18.56% 21.95% 38.56% 20.93% Fluazinam/Dimethomorph

Formulation 54.07% 23.05% 16.86% 6.02%

In order to determine a value of the severity index of the disease, the percentages of potatoes in each category of Table 1 are multiplied by its associated index value. The severity index can then be used to determine the percent control of each type of treatment. The severity index and percent control of each type of treatment is indicated in Table 2.

Table 2

Severity Index and Percent Control per treatment type

Based on the abovementioned Colby method for determining the expected fungicidal activity of a mixture the expected fungicidal control for the fluazinam/dimethomorph formulation is 39.06%. Therefore the Colby ratio of percent observed/percent expected is equal to 1.63, thereby showing synergism in the combination of dimethomorph and fluazinam against powdery scab.

In order to determine the vitality of the potato plant after soil application of the fungicides, the percentage of plant emergence was evaluated 3 weeks and 5 weeks after the soil application. The results are presented in Table 3.

Table 3

Percent plant emergence after application

% Emergence

3 WAA 5WAA

Control 86.25 96.25

Fluazinam 66.25 96.25

Dimethomorph 60 98.75 Fluazinam/Dimethomorph

Formulation 73.75 96.25

*WAA = Weeks after application

Based on the results presented hereinabove, the fungicidal composition comprising dimethomorph and fluazinam was found to exhibit a strong synergistic effect against Spongospora subterranea f. sp. Subterranean.

The results show that a synergistic combination of a morpholine fungicide (e.g. dimethomorph) and a pyridine fungicide (e.g. fluazinam) is suitable for controlling and/or preventing diseases in agriculturally important plants or propagation material thereof caused by Spongospora subterranea f. sp. Subterranean.

All publications, patents and patent applications mentioned in this specification are herein incorporated in their entirety by reference into the specification, to the same extent as if each individual publication, patent or patent application was specifically and individually indicated to be incorporated herein by reference.

Features of the disclosed embodiments may be combined, rearranged, omitted, etc., within the scope of the present disclosure to produce additional embodiments. Furthermore, certain features may sometimes be used to advantage without a corresponding use of other features.

It is, thus, apparent that there is provided, in accordance with the present disclosure methods and uses of a synergistic fungicidal. Many alternatives, modifications, and variations are enabled by the present disclosure. While specific embodiments have been shown and described in detail to illustrate the application of the principles of the present subject matter, it will be understood that the present subject matter may be embodied otherwise without departing from such principles. Accordingly, Applicant intends to embrace all such alternatives, modifications, equivalents, and variations that are within the spirit and scope of the present subject matter.