WO2021148330A1 - Method for reducing insect-vectored virus infections in grass plants - Google Patents

Abstract

The present invention is directed to methods of reducing insect-vectored viral infection and transmission in plants, more specifically grass plants, methods of reducing damage to plants caused by viral infection, and methods of crop enhancement including methods for improving plant growth, vigour and yield, by application of a seed treatment comprising a plant activator.

Description

METHOD FOR REDUCING INSECT-VECTORED VIRUS INFECTIONS IN GRASS PLANTS

Field of the Invention

The present invention is directed to methods of reducing insect-vectored viral infections and transmission in plants, in particular grass (Poaceae) plants, more particular cereals, methods of reducing damage to plants caused by viral infection, methods of crop enhancement including methods for improving plant growth, vigour and yield, by application of a seed treatment comprising at least one plant activator, to compositions comprising the combinations and to plant propagation material treated therewith.

Background of the Invention

Insect-vectored virus infections are a particularly difficult issue for the agriculture industry that typically results in considerable damage to grass, in particular cereal plant stocks, leading sometimes to total loss of harvest. This insect-vectored viral infection is most severe for insects that are either resistant to the presently known treatments, or where existing treatments may no longer be possible. Treatment practice thus far had focused on phytosanitary measures and strategies, attempting to control emergence and/or population density of the pests transmitting the virus; and, more recently, in introducing virus-resistant traits into plants. Phytosanitary strategies traditionally are based on agrochemical control of the virus vectors, as well as, where possible, timing the sowing process to a point in time where high infection load of the vector insects on the seedlings and young plants can be avoided, e.g. late sowing. Resistance increasing traits are usually introduced by genetically modifying plants, or selective breeding techniques.

However, both approaches are only of limited or local success, due to increasing pest resistances and environmental pressure, and the issues with potential introduction of undesired traits into the biosphere. Therefore, effective prevention and control of Gemini virus diseases has remained an issue to be solved. Also, there remains a need for the provision of methods and materials that permit to increase the resistance to viral infections, and to reduce the impact of such infections on the plant health. Of the pest-vectored viral infections that affect grass plants in general, and cereals more specifically, members of the plant virus taxonomic family Geminiviridae, such as Barley yellow dwarf virus (BYDV) or Wheat Dwarf Virus have had the strongest economic impact. Hence there remains the need to increase the virus resistance of non-modified and/or modified grass plants to such viral infections.

Hence, there thus exists a need for alternative methods for controlling insect-vectored viral infection and transmission in plants, and for reducing the damage to plants caused by such viral infections, especially useful plants such as crops, ideally without the need to also apply insecticides.

Summary of the Invention

It has now been surprisingly found that a seed treatment composition comprising a plant activator, and optionally, one or more other active ingredients, such as insecticides, is particularly effective in reducing viral infection and transmission in plants, in particular in grass crops, more specifically cereal crops.

Accordingly, in one aspect, the present invention provides a method of reducing insect-vectored viral infection in a plant, plants of the crops: grass crops including, but not limited to, cereals (wheat, barley, rye, oats, maize, rice, sorghum, triticale and related crops); leguminous plants (beans, lentils, peas, soybeans); oil plants (rape, mustard, canola, sunflowers); cucumber plants (marrows, cucumbers, melons); fibre plants (cotton, flax, hemp, jute); vegetables (spinach, lettuce, asparagus, cabbages, broccoli, cauliflower, carrots, onions, tomatoes, peppers, potatoes, paprika); as well as ornamentals (flowers, shrubs, broad-leaved trees and evergreens, such as conifers, also including transgenic crop plants of the foregoing types.

Preferably, the plants comprise cereals, such as wheat, barley, rye, oats, maize, the latter including field corn, popcorn and corn, rice, sorghum and related crops; sugar cane and turf grasses including, for example, cool-season turf grasses (for example, bluegrasses (Poa L), such as Kentucky bluegrass (Poa pratensis L), rough bluegrass (Poa trivialis L), Canada bluegrass (Poa compressa L.) and annual bluegrass (Poa annua L); bentgrasses (Agrostis L), such as creeping bentgrass (Agrostis palustris Huds.), colonial bentgrass (Agrostis tenius Sibth.), velvet bentgrass (Agrostis canina L.) and redtop (Agrostis alba L); fescues (Festuca L), such as tall fescue (Festuca arundinacea Schreb.), meadow fescue (Festuca elatior L) and fine fescues such as creeping red fescue (Festuca rubra L), chewings fescue (Festuca rubra var. commutata Gaud.), sheep fescue (Festuca ovina L) and hard fescue (Festuca longifolia); and ryegrasses (Lolium L), such as perennial ryegrass (Lolium perenne L) and annual (Italian) ryegrass (Lolium multiflorum Lam.)) and warm-season turf grasses (for example, Bermudagrasses (Cynodon L. C. Rich), including hybrid and common Bermudagrass; Zoysiagrasses (Zoysia Wil Id .), St. Augustinegrass (Stenotaphrum secundatum (Walt.) Kuntze); and centipedegrass (Eremochloa ophiuroides (Munro.) Hack.)).

This invention comprises a novel plant activator seed treatment that strengthens grass plants, preferably cereal crop plants, such as wheat, oats, barley, rye, and rice, helping to suppress or at least significantly reduce insect-vectored viral infection in the grass plant, and greatly reducing stress and increasing yield.

While this invention is applicable to any of the cereal crops, the examples in this application show the efficacy for at least winter wheat and winter barley using these cereal grains as seeds as an embodiment.

Accordingly, it is a primary object of the present invention to provide a method for increasing the straw strength and root development of cereal crops while increasing the amount of yield. This and further objects and advantages will be apparent to those skilled in the art in connection with the detailed description of the preferred embodiments set forth below.

The compositions of the invention may be applied to plant propagation material prior to the sowing or seeding process, or, onto the propagation material while sowing. Accordingly, the present invention provides methods as described herein comprising the application of a combination of the invention to a plant propagation material.

In an additional aspect, the present invention provides a method of reducing insect-vectored -viral transmission amongst plants by application of a plant activator. In a further aspect, the present invention provides a method of reducing damage to a plant caused by one or more insect-vectored viral infections, by application of a plant activator-comprising seed treatment composition. In a further aspect, the present invention provides a method of improving the growth of a plant by application of a plant activator-comprising seed treatment composition. In a further aspect, the present invention provides a method of increasing the yield of a plant by application of a plant activator-comprising seed treatment composition. In yet a further aspect, the present invention provides a method of improving plant vigour by application of plant activator-comprising seed treatment composition. In yet a further aspect, the present invention provides a method of improving the tolerance of plants to abiotic stress by application of a plant activator-comprising seed treatment composition. In additional aspects, the present invention provides a composition for treatment of the plant propagation material, comprising a plant activator, for use in the methods of the present invention. In additional aspects, the present invention provides a synergistic combination of one or more of suitable active compounds and a plant activator in a seed treatment composition for use in the methods of the present invention. In further additional aspects, the present invention provides for the use of a combination of a plant activator comprising seed treatment composition in the methods of the present invention. In yet further additional aspects, the present invention provides a kit of parts suitable for use in the methods of the present invention, comprising a first component comprising at least one seed treatment component and a second component comprising a plant activator, for the simultaneous, separate or sequential application to plant propagation material.

Plant activators are typically substances that protect plants by activating their defence mechanisms against pests or diseases. Preferably, plant activators suitable for use in the methods of the present invention are functional analogues of salicylic acid, and more preferably those able to induce systemic acquired resistance in plants to Fungi. More preferably, these include, for example, acibenzolar, acibenzolar-S-methyl and probenazole. Mixtures of plant activators can also be used in the present invention. In preferred embodiments of the invention, the plant activator is acibenzolar-S-methyl. Without wishing to be bound to any particular theory, it is believed that salicylic acid and synthetic analogues can activate a systemic acquired resistance (SAR) in plants. However, thus far this was only known as to induce resistance against fungal and bacterial infections, and abiotic stress. Accordingly, previously described treatments including such compounds were only disclosed for insect-controlled viral infections in a combination with an insecticide. Applicants now have surprisingly found that the use of such plant activators in seed treatments, even in absence of insecticides, allows grass plants derived from the seeds to develop an induced resistance to the insect-vectored viral infections.

Particularly suitable plant activators for use in the methods of the present invention include, acibenzolar, acibenzolar-S-methyl and probenazole, and at least one agrochemically acceptable carrier or diluent. Accordingly, in a first preferred aspect, the present invention provides a method of reducing insect-vectored viral infection in a plant by application of a seed treatment composition comprising acibenzolar-S-methyl.

The term "increasing the yield" of a plant means that the yield of a product of the plant is increased by a measurable amount over the yield of the same product of the plant produced under the same conditions, but without the application of the combinations according to the present invention. It is preferred that the yield is increased by at least about 0.5%, preferably 1%, more preferably 2%, yet more preferably 4% or more. Even more preferred is an increase in yield of at least about 5%, 10%, 15% or 20% or more.

According to the present invention, 'crop enhancement' means an improvement in plant vigour, an improvement in plant quality and/or improved tolerance to stress factors.

According to the present invention, an 'improvement in plant vigour' means that certain traits are improved qualitatively or quantitatively when compared with the same trait in a control plant which has been grown under the same conditions in the absence of the method of the invention. Such traits include, but are not limited to, early and/or improved germination, improved emergence, the ability to use less seeds, increased root growth, a more developed root system, increased root nodulation, increased shoot growth, increased tillering, stronger tillers, more productive tillers, increased or improved plant stand, less plant verse (lodging), an increase and/or improvement in plant height, an increase in plant weight (fresh or dry), bigger leaf blades, greener leaf colour, increased pigment content, increased photosynthetic activity, earlier flowering, longer panicles, early grain maturity, increased seed, fruit or pod size, increased pod or ear number, increased seed number per pod or ear, increased seed mass, enhanced seed filling, less dead basal leaves, delay of senescence, improved vitality of the plant, increased levels of amino acids in storage tissues and/or less inputs needed (e.g. less fertiliser, water and/or labour needed). A plant with improved vigour may have an increase in any of the aforementioned traits or any combination or two or more of the aforementioned traits.

According to the present invention, an 'improvement in plant quality' means that certain traits are improved qualitatively or quantitatively when compared with the same trait in a control plant which has been grown under the same conditions in the absence of the method of the invention. Such traits include, but are not limited to, improved visual appearance of the plant, reduced ethylene (reduced production and/or inhibition of reception), improved quality of harvested material, e.g. seeds, fruits, leaves, vegetables (such improved quality may manifest as improved visual appearance of the harvested material), improved carbohydrate content (e.g. increased quantities of sugar and/or starch, improved sugar acid ratio, reduction of reducing sugars, increased rate of development of sugar), improved protein content, improved oil content and composition, improved nutritional value, reduction in anti- nutritional compounds, improved organoleptic properties (e.g. improved taste) and/or improved consumer health benefits (e.g. increased levels of vitamins and anti-oxidants)), improved post-harvest characteristics (e.g. enhanced shelf-life and/or storage stability, easier processability, easier extraction of compounds), more homogenous crop development (e.g. synchronised germination, flowering and/or fruiting of plants), and/or improved seed quality (e.g. for use in following seasons). A plant with improved quality may have an increase in any of the aforementioned traits or any combination or two or more of the aforementioned traits.

According to the present invention, an 'improved tolerance to stress factors' means that certain traits are improved qualitatively or quantitatively when compared with the same trait in a control plant which has been grown under the same conditions in the absence of the method of the invention. Such traits include, but are not limited to, an increased tolerance and/or resistance to abiotic stress factors which cause sub-optimal growing conditions such as drought (e.g. any stress which leads to a lack of water content in plants, a lack of water uptake potential or a reduction in the water supply to plants), cold exposure, heat exposure, osmotic stress, UV stress, flooding, increased salinity (e.g. in the soil), increased mineral exposure, ozone exposure, high light exposure and/or limited availability of nutrients (e.g. nitrogen and/or phosphorus nutrients). A plant with improved tolerance to stress factors may have an increase in any of the aforementioned traits or any combination or two or more of the aforementioned traits. In the case of drought and nutrient stress, such improved tolerances may be due to, for example, more efficient uptake, use or retention of water and nutrients.

International patent application WO 2008/020998 refers to the in-furrow use of an Acibenzolar-S- methyl (S-methyl benzo[l,2,3]thiadiazole-7-carbothioate) treatment for controlling fungi and bacteria fungicide application for reducing plant damage by control of insect-vectored viral infection. Also, in WO 2011/134876, various combinations of anthranilic bis-amide or an aminothiadiazole insecticides with Acibenzolar-S-methyl are disclosed to control the insect-vectored spread of tomato yellow leaf curl virus (TYLC) in tomatoes, using a foliar or a soil drench application once a tomatoe plant had emerged.

The methods and compositions according to the invention are particularly suited in inducing resistance into grass plants against Gemini viruses, in particular BYVD and WVD. Gemini viruses possess single- stranded circular DNA genomes, falling into three genera, i.e. the leafhopper-transmitted Mastreviruses, such as maize streak virus, MSV; and the whitefly-transmitted Begomoviruses, such as bean golden mosaic virus, BGMV.

Gemini viruses are highly dependent on the DNA replication and RNA transcription systems of host plant cells to complete their own replication and transcription processes. In the past decades the disease caused by the Gemini virus family have evolved from local to one of the most important plant virus diseases in the world, affecting important food grass crops such as corn, wheat, barley, and may other closely related crops. Accordingly, the present invention provides for a novel use of salicylic acid analogues plant activators for the induction of viral resistance to grass plants through seed treatment.

Any or all of the above crop enhancements may lead to an improved yield by improving e.g. plant physiology, plant growth and development and/or plant architecture of grass crops such as corn, wheat, barley, and may other closely related crops.

In the context of the present invention 'yield' includes, but is not limited to, (i) an increase in biomass production, grain yield, starch content, oil content and/or protein content, which may result from (a) an increase in the amount produced by the plant per se or (b) an improved ability to harvest plant matter, (ii) an improvement in the composition of the harvested material (e.g. improved sugar acid ratios, improved oil composition, increased nutritional value, reduction of anti-nutritional compounds, increased consumer health benefits) and/or (iii) an increased/facilitated ability to harvest the crop, improved processability of the crop and/or better storage stability/shelf life. Increased yield of an agricultural plant means that, where it is possible to take a quantitative measurement, the yield of a product of the respective plant is increased by a measurable amount over the yield of the same product of the plant produced under the same conditions, but without application of the present invention. According to the present invention, it is preferred that the yield be increased by at least 0.5%, more preferred at least 1%, even more preferred at least 2%, still more preferred at least 4% , preferably 5% or even more.

Any or all of the above crop enhancements may also lead to an improved utilisation of land, i.e. land which was previously unavailable or sub-optimal for cultivation may become available. For example, plants which show an increased ability to survive in drought conditions, may be able to be cultivated in areas of sub-optimal rainfall, e.g. perhaps on the fringe of a desert or even the desert itself.

The plant propagation material is usually treated with a composition of the invention before the material is sown or planted. Alternatively, the plant propagation material may be treated with a composition of the invention during sowing or planting. Additionally, the composition of the invention may be applied to the previously treated propagation material before or during its planting. The composition of the invention may be during the sowing of the seed. The composition may also be used to plant propagation material derived from plants grown in a green house and/or during transplantation.

In the seed treatment composition according to the invention, convenient rates of application range of from 10 mg to 1 g of active substance per kg of seeds.

In an additional aspect, the present invention provides an agrochemical composition comprising a plant activator, together with an agrochemically acceptable diluent or carrier. In a preferred aspect, other active ingredients may be combined with the plant activator, more preferably in a ratio of 1 to 50 parts of the plant activator, the second and further active ingredient, by weight, together with an agrochemically acceptable diluent or carrier. In a preferred embodiment, the present invention provides an agrochemical composition comprising one or more additional active ingredients, and acibenzolar, acibenzolar-S-methyl or probenazole, in a ratio of 10 to 40 parts to 1 to 10 parts plant activator, by weight, together with an agrochemically acceptable diluent or carrier. In a most preferred embodiment, the present invention provides an agrochemical composition comprising a combination of one or more active component and acibenzolar-S-methyl, in a ratio of 10 to 40 parts of the active component to 1 to 10 parts plant activator, by weight, together with an agrochemically acceptable diluent or carrier.

The term "plant propagation material" is understood to denote all the generative parts of the plant, such as seeds, which can be used for the multiplication of the latter including vegetative plant material such as cuttings. There may be mentioned, as plant propagation material, seeds (in the strict sense), roots, fruits, tubers, bulbs, rhizomes, parts of plants.

Further, the present invention is also applicable for use with a plant propagation material that has already undergone a treatment with a pesticide.

Even distribution of the combination of the invention and adherence thereof to the propagation material is desired during the treatment process, this is particularly preferable when the propagation material is a seed (e.g. a cereal seed). The treatment could vary from a thin film of the formulation containing the combination of the invention on a plant propagation material, such as a seed, where the original size and/or shape are recognizable to a thick film (such as a coating or pelleting with many layers of different materials (such as carriers, for example, clays; different formulations, such as of active ingredients; polymers; and colourants) where the original shape and/or size of the seed is no longer recognisable.

Accordingly, in one embodiment the combination of the invention is adhered to the propagation material, such as a seed. In an alternative embodiment, the combination of the invention is present on the seed in a pelleted form.

Although it is believed that the present method can be applied to a seed in any physiological state, it is preferred that the seed be in a sufficiently durable state that it incurs no damage during the treatment process. Typically, the seed would be a seed that had been harvested from the field; removed from the plant; and separated from any cob, stalk, outer husk, and surrounding pulp or other non-seed plant material. The seed would preferably also be biologically stable to the extent that the treatment would cause no biological damage to the seed. It is believed that the treatment can be applied to the seed at any time between harvest of the seed and sowing of the seed or during the sowing process (seed directed applications).

The seed treatment occurs to an unsown seed, and the term "unsown seed" is meant to include seed at any period between the harvest of the seed and the sowing of the seed in the ground for the purpose of germination and growth of the plant. Treatment to an unsown seed is not meant to include those practices in which the pesticide is applied to the soil but would include any application practice that would target the seed during the sowing/planting process.

The treated plant propagation material of the present invention can be treated in the same manner as conventional plant propagation material. The treated propagation material can be stored, handled, sowed and tilled in the same manner as any other pesticide treated material, such as seeds. Preferably, the treatment occurs before sowing of the seed so that the seed being sown or planted has been pre treated.

The compositions and methods of the present invention may particularly be used for the treatment of any cereals, such as wheat, barley, rye, oats, maize, the latter including field corn, pop corn and corn, rice, sorghum and related crops; sugar cane and turf grasses including, for example, cool-season turf grasses (for example, bluegrasses (Poa L), such as Kentucky bluegrass (Poa pratensis L), rough bluegrass (Poa trivialis L), Canada bluegrass (Poa compressa L.) and annual bluegrass (Poa annua L); bentgrasses (Agrostis L), such as creeping bentgrass (Agrostis palustris Huds.), colonial bentgrass (Agrostis tenius Sibth.), velvet bentgrass (Agrostis canina L) and redtop (Agrostis alba L); fescues (Festuca L), such as tall fescue (Festuca arundinacea Schreb.), meadow fescue (Festuca elatior L) and fine fescues such as creeping red fescue (Festuca rubra L), chewings fescue (Festuca rubra var. commutata Gaud.), sheep fescue (Festuca ovina L) and hard fescue (Festuca longifolia); and ryegrasses (Lolium L), such as perennial ryegrass (Lolium perenne L.) and annual (Italian) ryegrass (Lolium multiflorum Lam.)) and warm-season turf grasses (for example, Bermudagrasses (Cynodon L. C. Rich), including hybrid and common Bermudagrass; Zoysiagrasses (Zoysia Willd.), St. Augustinegrass (Stenotaphrum secundatum (Walt.) Kuntze); and centipedegrass (Eremochloa ophiuroides (Munro.) Hack.)).

Suitable plants may also include plants that have been rendered tolerant to herbicides like bromoxynil or classes of herbicides (such as HPPD inhibitors, ALS inhibitors; for example primisulfuron, prosulfuron and trifloxysulfuron, EPSPS (5-enol-pyrovyl-shikimate-3-phosphate-synthase) inhibitors, GS (glutamine synthetase) inhibitors or PPO (protoporphyrinogen-oxidase) inhibitors) as a result of conventional methods of breeding or genetic engineering. An example of a crop that has been rendered tolerant to imidazolinones (e.g. imazamox) by conventional methods of breeding (mutagenesis) is Clearfield^® summer rape (Canola). Examples of crops that have been rendered tolerant to herbicides or classes of herbicides by genetic engineering methods include glyphosate- and glufosinate-resistant maize varieties commercially available under the trade names RoundupReady^® , Herculex I^® and LibertyLink^®. Suitable plants also include plants which have been so transformed by the use of recombinant DNA techniques that they are capable of synthesising one or more selectively acting toxins, such as are known from toxin-producing bacteria, especially those of the genus Bacillus.

Suitable plants also include plants which have been so transformed by the use of recombinant DNA techniques that they are capable of synthesising antipathogenic substances having a selective action, such as the so-called "pathogenesis-related proteins" (PRPs, see e.g. European patent application EP 0,392,225). Examples of such antipathogenic substances and transgenic plants capable of synthesising such antipathogenic substances are known, for example, from European patent applications EP 0,392,225 and EP 0,353,191 and International patent application WO 95/33818. The methods of producing such transgenic plants are generally known to the person skilled in the art and are described, for example, in the publications mentioned above. Accordingly, in a preferred embodiment, the present invention provides a method of reducing insect- vectored viral infection in a cereal plant by application of a seed treatment composition comprising acibenzolar-S-methyl.

In an additional preferred embodiment, the present invention provides a method of reducing insect- vectored viral transmission to or amongst grass plants, by application of a seed treatment composition comprising acibenzolar-S-methyl.

In a further preferred embodiment, the present invention provides a method of reducing damage to a cereal plant caused by one or more insect-vectored viral infections, in a cereal plant by application of a seed treatment composition comprising acibenzolar-S-methyl.

In a further preferred embodiment, the present invention provides a method of improving the growth of a cereal plant by application of a seed treatment composition comprising acibenzolar-S-methyl.

In a further preferred embodiment, the present invention provides a method of increasing the yield of a cereal plant by application of a seed treatment composition comprising acibenzolar-S-methyl.

In a further preferred embodiment, the present invention provides a method of improving cereal plant vigour by application of a seed treatment composition comprising acibenzolar-S-methyl.

In a further preferred embodiment, the present invention provides a method of increasing the tolerance of cereal plant to abiotic stress by application of a seed treatment composition comprising acibenzolar- S-methyl.

In additional preferred embodiments, the present invention provides a seed treatment composition comprising acibenzolar-S-methyl, for use in the methods of the present invention, wherein the plant is a cereal plant. In further additional preferred embodiments, the present invention provides for the use of a seed treatment composition comprising acibenzolar-S-methyl, in the methods of the present invention, wherein the plant is a cereal plant.

In yet additional preferred embodiments, the present invention provides a kit of parts suitable for use in the methods of the present invention, comprising acibenzolar-S-methyl, for the simultaneous, separate or sequential application to grass, preferably cereal plant propagation material, such as seeds.

The present invention additionally provides for a plant or plant propagation material treated with a combination of the invention as defined herein.

More specifically, the present methods and seed treatment compositions according to the present invention is suitable for plants from the grass family, in particular cereal crops.

The compositions and methods of the present invention are particularly suitable for the treatment of plants which are susceptible to damage by insect-vectored viral infections transmitted by leafhoppers , aphids, thirps, planthoppers, whiteflies or other virus-transmitting pest vectors.

Accordingly, in a preferred embodiment, the present invention provides a method of reducing insect- vectored viral infection in a cereal plant by application of a seed treatment composition comprising acibenzolar-S-methyl, wherein the plant is susceptible to damage by viral infections transmitted by aphids or leafhoppers capable of transmitting BYDV or WDV, in particular Psammotettix alienus (leafhopper); Metopolophium dirhodum (METODR) (rose-grain aphid), Rhopalosiphum padi (RHOPPA) (bird cherry-oat aphid) and /or Sitobion avenae (MACSAV) (english grain aphid).

Wheat dwarf virus (WDV) is known to be transmitted by the leafhopper (Psammotettix alienus). There are other leafhopper species occurring in cereal fields which cannot easily differentiated from P. alienus. BYDV is known to be transmitted by aphid species capable of transmitting BYDV, e.g., Metopolophium dirhodum (METODR), Rhopalosiphum padi(RHOPPA) and Sitobion avenae (MACSAV). In an additional preferred embodiment, the present invention provides a method of reducing insect- vectored viral transmission amongst cereal plants by application of a seed treatment comprising acibenzolar-S-methyl, wherein the plant is susceptible to damage by Gemini viral infections transmitted by an aphid or a leafhopper, more specifically, a species selected from Psammotettix alienus; Metopolophium dirhodum (METODR), Rhopalosiphum padi(RHOPPA) and Sitobion avenae (MACSAV).

In a further preferred embodiment, the present invention provides a method of reducing damage to a plant caused by one or more viral infections transmitted by aphid or leafhopper, more specifically, a species selected from Psammotettix alienus; Metopolophium dirhodum (METODR), Rhopalosiphum padi (RHOPPA) and Sitobion avenae (MACSAV), by application of a seed treatment comprising acibenzolar-S- methyl.

In a further aspect, the present invention provides a method of reducing damage to grass plants caused by aphid or leafhopper, more specifically, a species selected from Psammotettix alienus; Metopolophium dirhodum (METODR), Rhopalosiphum padi (RHOPPA) and Sitobion avenae (MACSAV), by application of a seed treatment comprising a plant activator.

Normally, a grower in the management of his crop would use one or more other agronomic chemicals in addition to the combination of the present invention. Examples of agronomic chemicals include herbicides, pesticides, such as fungicides, herbicides, insecticides, bactericides, acaricides, nematicides, plant nutrients and plant fertilizers.

Accordingly, the present invention provides for the use of a composition according to the present invention comprising a plant activator together with one or more active ingredient, such as herbicides, fungicides, insecticides, nematicides, plant nutrients or plant fertilizers.

Suitable examples of plant nutrients or plant fertilizers are calcium sulfate CaS0 , calcium nitrate Ca(N0₃)₂.4H₂0, calcium carbonate CaC0₃, potassium nitrate KN0₃, magnesium sulfate MgS0₄, potassium hydrogen phosphate KH₂P0₄, manganese sulfate MnS0₄, copper sulfate CuS0₄, zinc sulfate ZnS0₄, nickel chloride NiCI₂, cobalt sulfate CoS0 , potassium hydroxide KOH, sodium chloride NaCI, boric acid H₃B0₃ and metal salts thereof, Na₂Mo04. The nutrients may be present in an amount of 5% to 50% by weight, preferably of 10% to 25% by weight or of 15% to 20% by weight each. Preferred additional nutrients are urea, melamine, potassium oxide, and inorganic nitrates. The most preferred additional plant nutrient is potassium oxide. Where the preferred additional nutrient is urea, it is present in an amount of generally 1% to 20% by weight, preferably 2% to 10% by weight or of 3% to 7% by weight.

Seed Treatment

In the treatments or applications of the invention the components of the invention are generally in the form of a formulation containing other customary formulation adjuvants because it allows, for example, less burdensome handling and application.

In an embodiment, the composition comprising the plant activator is a single composition that has been specifically formulated, the composition comprising at least one of the adjuvants customary in formulation technology, such as extenders, e.g., solvents or solid carriers, or surface-active compounds (surfactants).

Suitable formulation adjuvants are, for example, solid carriers, solvents, stabilisers, slow-release adjuvants, dyes and optionally surface-active substances (surfactants). Suitable carriers and adjuvants in this case include all substances customarily used in crop protection products, especially in products for controlling snails and slugs. Suitable adjuvants, such as solvents, solid carriers, surface-active compounds, non-ionic surfactants, cationic surfactants, anionic surfactants and further adjuvants in the compositions used in accordance with the invention are, for example, the same as those described in EP 0,736,252.

The compositions may comprise from 0.1 to 99 %, in particular 0.1 to 95 %, of the combination and from 1 to 99.9 %, in particular 5 to 99.9 %, of at least one solid or liquid auxiliary. The composition may additionally comprise from 0 to 25 %, in particular 0.1 to 20 %, of surfactants (% is in each case per cent by weight). While concentrated compositions are more preferred as commercial goods, the end user generally uses dilute compositions that comprise considerably lower concentrations of the combination. Compositions of the present invention may contain from about 0.001% to about 99% by weight active ingredients. Suitably, the composition contains from about 0.001% to about 50% by weight active ingredients. More suitably, the composition contains from about 0.001% to about 10% by weight active ingredients. More suitably, the composition contains from about 0.001 % to about 1% by weight active ingredients. If the formulation is in the form of a concentrate, requiring dilution with water before use, it will contain a higher amount of active ingredients than a composition that is ready to use without dilution.

The rate of application of the compounds of the present invention may vary within wide limits and depends upon the nature of the soil, the method of application, the target insect pest to be controlled, the prevailing climatic conditions, and other factors governed by the method of application and the time of application.

Loading active ingredients onto a seed is an imperfect process and varies based on the active ingredient selected. The amount of active ingredient contained on an individual seed varies according to the treatment process and type.

The loading process of the present invention comprises direct seed slurry treatments using a spin disc applicator (e.g., Hege treater), batch or continuous flow treaters, fluidized bed applicators, rotostatic applicators, film coaters, pan coaters, bag treaters, and any other seed treatment process known in the art. Accordingly, by the process of the present invention, it is possible to achieve a specific loading rate on a per seed basis. More particularly, a loading rate of active ingredient as defined above may be loaded onto each individual seed.

In another embodiment of the present invention, a method is provided for treating plants or plant propagation materials with a composition comprising at least one plant growth regulator and a plant activator. The method may further optionally comprise an additional pesticide, as defined above.

When unconcerned about the amount of active ingredient on a per seed basis, the formulation can be applied to the seeds using conventional treating techniques and machines, such as fluidized bed techniques, the roller mill method, rotostatic seed treaters, and drum coaters. Other methods, such as spouted beds may also be useful. The seeds may be presized before coating. After coating, the seeds are typically dried and then transferred to a sizing machine for sizing. Such procedures are known in the art and are set out in more detail below.

The compositions and methods of the present invention may be useful on primed and unprimed seeds. Priming is a water-based process known in the art that is performed on seeds to increase uniformity of germination and emergence from a growing medium or soil, thus enhancing plant stand establishment.

As with priming, incorporation of the compositions and methods of the present invention into the priming process also increases the rate of emergence, so the plant stand establishes itself faster, ensuring maximum cartons of crop per acre at harvest. Wide ranges in times of seedling emergence decrease the amount of harvestable plants per acre, an undesirable situation for the commercial grower.

Normally, a tank-mix formulation for seed treatment application comprises 0.25 to 80%, especially 1 to 75 %, active ingredient compounds, and 99.75 to 20 %, especially 99 to 25 %, of a solid or liquid auxiliaries (including, for example, a solvent such as water), where the auxiliaries can be a surfactant in an amount of 0 to 40 %, especially 0.5 to 30 %, based on the tank-mix formulation.

Typically, a pre-mix formulation for seed treatment application comprises 0.5 to 99.9 %, especially 1 to 95 %, active ingredient compounds, and 99.5 to 0.1 %, especially 99 to 5 %, of a solid or liquid adjuvant (including, for example, a solvent such as water), where the auxiliaries can be a surfactant in an amount of 0 to 50 %, especially 0.5 to 40 %, based on the pre-mix formulation.

Whereas commercial products will preferably be formulated as concentrates (e.g., pre-mix composition (formulation)), the end user will normally employ dilute formulations (e.g., tank mix composition).

Preferred seed treatment pre-mix formulations include aqueous suspension concentrates, which may advantageously be applied to the seeds using conventional treating techniques and machines, such as fluidized bed techniques, the roller mill method, rotostatic seed treaters, and drum coaters. Other methods, such as spouted beds may also be useful. The seeds may be presized before coating.

After coating, the seeds are typically dried and then transferred to a sizing machine for sizing. Such procedures are known in the art.

A seed weight increaser can be any compound or composition which will increase the weight or density of a seed. In terms of amounts, one strives to increase by a sufficient amount to cause rice comprising the weight increaser to promptly settle onto the soil surface when soil-surface rice planting is performed. It will be apparent to skilled persons that the amount will necessarily vary depending on the planting conditions, seed variety and moisture content, and properties of the weight increaser. Examples include iron oxide such as in powder form, iron powder, quartz sand, barium sulfate, calcium carbonate, and zinc oxide.

Water-insoluble binders are known in the art and any which are suitable for application to a seed can be used in practicing the present invention. Examples include polyacrylate adhesive, PVAcA eoVA polyacrylate, EVA, polyurethane, and PVAc. A specific example is Mowinyl-Powder DM2072P copolymer of VA, VeoVA, acrylate ester (Nippon Gohsei, Osaka, Japan).

Water soluble binders are known in the art and any which are suitable for application to a seed can be used in practicing the present invention. Examples include polyvinyl alcohol, CMC, HPMC and PVP. A specific example is PVA1 17S polyvinyl alcohol (Kuraray, Tokyo, Japan).

Compositions according to the invention are efficacious, offering improved emergence and prompt progression through growth stages. The composition provides good results for hardness, stability and adhesive properties in the treated seed. Handling properties during the coating process are sufficiently good to be used at a commercial scale.

The individual components of the composition are preferably mixed together. In addition to the active ingredients, weight increaser, water-insoluble binders and optional water-soluble binder, one or more agrochemicals such as those exemplified herein may optionally be provided. The seeds are preferably placed in a container and water is sprayed on the seeds to moisten the surface and be available to adhere the powdered composition. According to one method, a portion of the coating composition is added, and the seeds are stirred to distribute the composition and allow it to bind to the seeds. The water spraying/composition adding steps are then repeated until all the composition has been added to the seeds. The seeds are allowed to dry until the moisture level of the rice is back to the original state. A typical seed moisture level is about 15%. Although the method of alternating water spraying/composition adding steps can be suitable, another method for treating seeds with the inventive compositions uses a continuous or parallel process.

In such a process, once the water begins spraying on the seeds the dry composition is gradually but steadily introduced, and these inputs continue in parallel while stirring the seeds until the coating process is completed and the seeds are allowed to dry.

In addition to the possibility of adding one or more agrochemicals to the ingredients of the composition, it is also contemplated that seeds could first be treated with one or more agrochemicals before adding the inventive composition. It is also possible that one or more agrochemicals is added as a separate ingredient during the course of applying the inventive composition. Alternatively, after applying the inventive composition one or more agrochemicals may be added in a subsequent step.

Good results are usually achieved when only enough water is used to moisten the seeds and bind the composition to them. This is not to be regarded as a soaking step as the minimum water amounts used with the invention result in little, if any, water being taken up by the seed which would otherwise trigger germination or deteriorate seed quality. In fact an advantage the inventive process has over the prior art is that, when the composition uses iron oxide, the risk of explosion during the process is minimal. In prior art uses of finely ground iron powder, the risk of explosion during the coating process needs to be mitigated by mixing the iron with water, but that water has an undesired effect on the seed and can require additional energy inputs to dry the seed after treatment.

It has been observed that either dividing the materials to be applied into several aliquots and adding them at separate times or alternatively using a continuous application route can give a consistent outcome, especially where small batches of seeds are treated. Adding all of the coating composition in a single step may however form granules which do not necessarily all stick to the seed, and where they do adhere the coating may not be of a sufficiently high quality in terms of visual appearance and technical performance, or the size of the granule differ widely, which may result in issues during sowing. Although any appropriate mixing vessel or container could be sufficient, it is contemplated that a pan granulator or rotational-type mixer, such as that used in building trades to mix concrete, can provide good results in particular when seeds are treated at a commercial scale. A skilled person will appreciate how the method to apply the dry composition can be similar to the process of pelleting seeds. Equipment and techniques useful for pelleting may find use with the present invention. When using such equipment a continuous process can be preferred. The drying step may be at any suitable temperature and humidity. It is believed drying at room temperature or slightly heated temperature, e.g. 35°C, for about 1 day may provide good results with a minimum of energy inputs. A fluidized dryer can be used for the drying step; such machines may be an efficient means to provide warm air.

Agrochemicals and Active Ingredients Seeds treated with the composition of the invention may further include an agrochemical applied simultaneously or separately. Such agrochemicals can include fungicides, insecticides, bactericides, acaricides, nematicides and/or plant growth regulators. These agents may be provided as formulations comprising, inter alia, carriers, surfactants or application promoting adjuvants customarily employed in the art of formulation. The present invention is also suitable for use with other agrochemicals such as primers and safeners.

Examples of suitable agrochemicals include the following: Insecticides such as benzoylureas, carbamates, chloronicotinyls, diacylhydrazines, diamides, fiproles, macrolides, neonicotinoids, nitroimines, nitromethylenes, organochlorines, organophosphates, organosilicons, organotins, phenylpyrazoles, phosphoric esters, pyrethroids, spinosyns, tetramic acid derivatives and tetronic acid derivatives.

Specific examples of preferred insecticides include thiamethoxam, clothianidin, imidacloprid, acetamiprid, dinotefuran, nitenpyram, thiacloprid, thiodicarb, aldicarb, carbofuran, furadan, fenoxycarb, carbaryl, sevin, ethienocarb, fenobucarb, chlorantraniliprole, cyantraniliprole, flubendiamide, spinosad, spinetoram, lambda- cyhalothrin, gamma-cyhalothrin, tefluthrin, fipronil, and sulfoxaflor.

Fungicides such as acycloamino acid fungicides, aliphatic nitrogen fungicides, amide fungicides, anilide fungicides, antibiotic fungicides, aromatic fungicides, arsenical fungicides, aryl phenyl ketone fungicides, benzamide fungicides, benzanilide fungicides, benzimidazole fungicides, benzothiazole fungicides, botanical fungicides, bridged diphenyl fungicides, carbamate fungicides, carbanilate fungicides, conazole fungicides, copper fungicides, dicarboximide fungicides, dinitrophenol fungicides, dithiocarbamate fungicides, dithiolane fungicides, furamide fungicides, furanilide fungicides, hydrazide fungicides, imidazole fungicides, mercury fungicides, morpholine fungicides, organophosphorous fungicides, organotin fungicides, oxathiin fungicides, oxazole fungicides, phenylsulfamide fungicides, polysulfide fungicides, pyrazole fungicides, pyridine fungicides, pyrimidine fungicides, pyrrole fungicides, quaternary ammonium fungicides, quinoline fungicides, quinone fungicides, quinoxaline fungicides, strobilurin fungicides, sulfonanilide fungicides, thiadiazole fungicides, thiazole fungicides, thiazolidine fungicides, thiocarbamate fungicides, thiophene fungicides, triazine fungicides, triazole fungicides, triazolopyrimidine fungicides, urea fungicides, valinamide fungicides, and zinc fungicides.

Specific examples of preferred fungicides include azoxystrobin, trifloxystrobin, fluoxastrobin, cyproconazole, difenoconazole, prothioconazole, tebuconazole, triticonazole, fludioxonil, thiabendazole, ipconazole, cyprodinil, myclobutanil, metalaxyl, metalaxyl-M (also known as mefenoxam), sedaxane, and penflufen.

Nematicides such as antibiotic nematicides, avermectin nematicides, botanical nematicides, carbamate nematicides, oxime carbamate nematicides, and organophosphorus nematicides.

Specific examples of preferred nematicides include abamectin, aldicarb, thiadicarb, carbofuran, carbosulfan, oxamyl, aldoxycarb, ethoprop, methomyl, benomyl, alanycarb, iprodione, phenamiphos (fenamiphos), fensulfothion, terbufos, fosthiazate, dimethoate, phosphocarb, dichlofenthion, isamidofos, fosthietan, isazofos ethoprophos, cadusafos, terbufos, chlorpyrifos, dichlofenthion, heterophos, isamidofos, mecarphon, phorate, thionazin, triazophos, diamidafos, fosthietan, phosphamidon, imicyafos, captan, thiophanate- methyl and thiabendazole. Nematicidally active biological agents include any biological agent that has nematicidal activity and could be used with the present invention. The biological agent can be any type known in the art including bacteria and fungi. The wording "nematicidally active" refers to having an effect on, such as reduction in damage caused by, agricultural-related nematodes. Examples of nematicidally active biological agents include Bacillus firmus, B. cereus, B. subtilis, Pasteuria penetrans, P. nishizawae, P. ramosa, P. thornei, and P. usgae. A suitable Bacillus firmus strain is strain CNCM 1-1582 which is commercially available as BioNem™. A suitable Bacillus cereus strain is strain CNCM 1-1562. Of both Bacillus strains more details can be found in US 6,406,690.

Examples of primers and safeners include benoxacor, cloquintocet-mexyl, cyometrinil, fenclorim, fluxofenim, oxabetrinil and daimuron.

The seed treatment composition comprises at least acibenzolar-S-methyl. Preferably, it may comprise at least one, or more preferably at elast two active ingredient components in addition to the presence of the salicylic acid analogue, optionally together with one or more customary formulation auxiliaries, wherein component (I) may be one or more insecticide, herbicide, fungicide, and/or plant growth enhancer or plant activator; and component (II) maybe is one or more different insecticide, herbicide, fungicide, plant activator and/or plant growth enhancer one or more plant activator(s).

In one embodiment, the weight ratio of active ingredients to the salicylic acid analogue is 5:1. In a further embodiment, the active ingredients and salicylic acid analogue, preferably acibenzolar-S-methyl, are present in a synergistically effective amount.

A particularly preferred mixture according to the invention comprises the active compound metalaxyl-M in combination with acibenzolar-S-methyl. In such a mixture, the weight ratio of the two active compounds to one another is between 1000:1 and 1:100, preferably between 625:1 and 1:100, particularly preferably between 125:1 and 1:50 and very particularly preferably between 25:1 and 1:5, where in the ratios here and below Metalaxyl-M is in each case mentioned first. A further particularly preferred mixture according to the invention comprises the active compound Fludioxonil in combination with acibenzolar-S-methyl. In the mixture, the weight ratio of the two active compounds to one another is between 1000:1 and 1:100, preferably between 625:1 and 1:100, particularly preferably between 125:1 and 1:50 and very particularly preferably between 25:1 and 1:5, where in the ratios here and below Fludioxonil is in each case mentioned first.

A further particularly preferred mixture according to the invention comprises the active compound Thiamethoxam in combination with Acibenzolar-S-methyl. In the mixture, the weight ratio of the two active compounds to one another is between 1000:1 and 1:100, preferably between 625:1 and 1:100, particularly preferably between 125:1 and 1:50 and very particularly preferably between 25:1 and 1:5, where in the ratios here and below Thiamethoxam is in each case mentioned first.

A particularly preferred mixture according to the invention comprises the active compound oxathiapiprolin in combination with acibenzolar-S-methyl. In the mixture, the weight ratio of the two active compounds to one another is between 1000:1 and 1:100, preferably between 625:1 and 1:100, particularly preferably between 125:1 and 1:50 and very particularly preferably between 25:1 and 1:2, where in the ratios here and below Oxathiapiprolin is in each case mentioned first.

Where three components are present, the amounts may range from 50 - 100 - 150 % per component.

Preferred mixtures in the sense of the present invention also include combinations of compounds from the group consisting of metalaxyl-M, fludioxonil, thiamethoxam, difenoconazol, tebuconazole, triticonazole, tefluthrin, oxathiapiprolin, azoxystrobin and/or cyantraniliprole, with acibenzolar-S- methyl.

Preferred mixtures in the sense of the present invention also include combinations of compounds from the group consisting of sedaxane, fludioxonil, difenoconazol, tebuconazole, tefluthrin, and/or triticonazole, with acibenzolar-S-methyl.

More preferably, the combinations can be as follows:

- fludioxonil, difenoconazole, tebuconazole, and acibenzolar-S-methyl;

- sedaxane, fludioxonil, difenoconazol, and acibenzolar-S-methyl; - sedaxane, fludioxonil, tebuconazole, and acibenzolar-S-methyl;

- sedaxane, fludioxonil, difenoconazol, tebuconazole, and acibenzolar-S-methyl;

- sedaxane, fludioxonil, and acibenzolar-S-methyl;

- sedaxane, fludioxonil, triticonazole, and acibenzolar-S-methyl; - sedaxane, fludioxonil, difenoconazol, triticonazole, and acibenzolar-S-methyl; or

- fludioxonil, tefluthrin, and acibenzolar-S-methyl.

Accoridng to the present invention, preferred application rates of Acibenzolar-S-methyl (ASM) to cereal seeds can be selected as follows (1 dt = 100 kg):

- from 0.25 to 100 g ASM/dt seed;

- from 0.25 to 50 g ASM/dt seed;

- from 0.5 to 50 g ASM/dt seed;

- from 1 to 50 g ASM/dt seed;

- from 1 to 30 g ASM/dt seed;

- from 1 to 20 g ASM/dt seed;

- from 2 to 20 g ASM/dt seed;

- from 2.5 to 20 g ASM/dt seed;

- from 2.5 to 10 g ASM/dt seed;

- from 4 to 10 g ASM/dt seed;

- from 2.5 to 7.5 g ASM/dt seed; and

- from 4 to 6 g ASM/dt seed. Most preferred application rates of Acibenzolar-S-methyl (ASM) to cereal seeds can be selected as follows (1 dt = 100 kg):

- from 1 to 7.5 g ASM/dt seed;

- from 2.5 to 7.5 g ASM/dt seed; and

- from 4 to 6 g ASM/dt seed. The cereal seed in the above mentioned preferred and most preferred application rates of Acibenzolar- S-methyl (ASM) can be more particularly a wheat or barley seed.

As noted above the agrochemicals or active ingredients of the invention may be provided in the form of formulated products. There can be many purposes for doing so, and for each a different component might be added. For example, it might be desired to protect seed during storage and transport from any toxicity issues associated with close physical proximity to an agrochemical. Many other purposes and solutions will be apparent to the skilled person.

A set out before, other additives which are used with seeds may advantageously be provided in conjunction with the present invention. Such additives include, but are not limited to, uv- protectants, colorants, brighteners, pigments, dyes, extenders, dispersing agents, excipients, anti-freeze agents, herbicidal safeners, seed safeners, seed conditioners, micronutrients, fertilizers, surfactants, sequestering agents, plasticizers, polymers, emulsifiers, flow agents, coalescing agents, defoaming agents, humectants, thickeners, and waxes. Such additives are commercially available and known in the art. The present invention additionally includes methods of treatment of seeds with the inventive composition, when the composition is in powdered form.

The invention will now be illustrate with the following, non-limiting examples:

Example 1: Trial results of seed treatments comprising Azibenzolar-S-Methyl to Barley yellow dwarf virus (BYDV) Wheat dwarf virus in Cereals

Seed Treatment compositions comprising acibenzolar-S-methyl and a carrier were prepared and applied to seeds of virus-sensitive winter barley and winter wheat varieties with known sensitivities.

A trial location was chosen at a location where insect-vectored damage had been reported previously, whereby early-sown winter cereals were most likely to be infested with aphids, and the location was chosen adjacent to old pastures and/or to crops of maize or autumn-sown cereals, both of which carried aphid populations, or exposed to volunteer plants and grasses carrying aphids, thereby creating a "green bridge". Distances between the plots were at least 0.5 m to discourage interplot spread.

After treatment, and compared to a control without a pre-treatment and compositions not including azibenzolar-S-methyl, it was concluded that all applications comprising of from 1 to 10 gai/dt of azibenzolar-S-methyl in wheat trials were highly effective (especially from 1 to 7.5 gai/dt of azibenzolar- S-methyl to seeds), and more effective than the controls and comparative examples, while operating at much lower concentration per seed. The outcome was that there were no visible virus symptoms in all trials. Also, a significant positive yield effect was found. Also, additional foliar application of azibenzolar- S-methyl did not result in an increased yield. Example 2: Winter Barley Trials

Repeating example 1, it was found that for winter barley, in six different trials at two distinct locations, a reliable and significant virus suppression was achieved. Best results were obtained from 1 to 7.5 gai/dt of azibenzolar-S-methyl to seeds.

Another object according to the present invention is directed to methods of reducing insect-vectored viral infections and transmission in sunflower (Helianthus) plants, methods of reducing damage to plants caused by viral infection, methods of crop enhancement including methods for improving plant growth, vigour and yield, by application of a seed treatment comprising at least one plant activator, to compositions comprising the combinations and to plant propagation material treated therewith.

Said another object is described in more details below.

More particularly, this another object is related to a method of reducing insect-vectored viral infection in a Sunflower (Helianthus) plant, by contacting plant propagation material prior to or during sowing and planting with a seed treatment composition comprising a plant activator.

The Sunflower plant propagation material can comprise sunflower seeds.

The Sunflower can be Helianthus annuus L. or a Helianthus tuberosus L.

The plant activator can be a salicylic acid analogue, and more preferably the salicylic acid analogue can comprise acibenzolar, acibenzolar-S-methyl or probenazole, preferably acibenzolar-S-methyl. The plant can be susceptible to damage by viral infections transmitted by insect vectors selected from the group consisting of aphids, whiteflies, leaf hoppers, thrips, beetles, weevils, nematodes, and mites.

The virus can be Cucumber mosaic virus, Pelargonium zonate spot virus, Sunflower chlorotic mottle virus; Sunflower mild mosaic virus; Sunflower mosaic virus; Sunflower necrosis virus, Tobacco streak virus; Sunflower ringspot virus; and Tobacco ringspot virus.

The plant propagation material can be treated before its planting, and/or during its planting.

The composition according to said another object, comprising at least the plant activator, can be applied as a seed treatment composition comprising an agrochemically acceptable diluent or carrier.

Said another object is also related to a method of protecting a sunflower plant against insect-vectored viral diseases by treating the plant propagation material with effective amounts consisting essentially of a salicylic acid analogue, preferably acibenzolar-S-methyl, and an agrochemically acceptable diluent or carrier.

In said protecting method, the plant propagation material can be a sunflower seed, and the plant activor can be present in anamount of from from 1 to 10, preferably of from 2 to 5 ml / 150.000 seeds.

Said another object is also related to an agrochemical seed treatment composition comprising essentially of a binary or teriary mixture of an effective amount of at least one salicylic acid analogue, at least one plant activator, at least a second and/or a third active ingredient, and a carrier or diluent, or a premix for application of the seed treatment in a solid or liquid formulation.

Said salicylic acid analogue can comprise acibenzolar, acibenzolar-S-methyl or probenazole, preferably acibenzolar-S-methyl, preferably in an amount of from 1 to 10, preferably of from 2 to 5 ml / 150.000 seeds.

Said second active ingredient can be present in a ratio by weight of 1:5000 to 5000:1. The plant activator, the first and the second active ingredients can be present in a range of from 50 - 100 - 150 % per component.

The seed treatment composition can consist essentially of an effective amount of at acibenzolar-S- methyl, and a carrier or diluent, or a premix for application of the seed treatment in a solid or liquid form, wherein a second and third active ingredients can preferably be present in a range of ratios by weight of from 1:1 to 1:50.

In a particular embodiment, the seed treatment composition can comprise the acibenzolar-S-methyl, and the first and second active ingredient or a second and third active ingredients in an amount of from 1:1:1, to 1:50:150, to 150:50:1.

The seed treatment composition can comprise at least two active ingredient components optionally together with one or more customary formulation auxiliaries, wherein components (I) and (II) include one or more insecticides and one or more fungicides(s) selected from the group consisting of thiamethoxam, oxathiapiprolin, azoxystrobin, cyantraniliprole, ludioxonil, metalaxyl, metaxalyl-M, mefenoxam, azoxystrobin, difenoconazole and/or myclobutanil.

Said another object is also related to a plant propagation material which has been treated with said composition.

Said another object is also related to a kit of parts suitable for use in the above-mentioned methods, said kit comprising acibenzolar-S-methyl, and a diluent or carrier, or precursor thereof, for the simultaneous, separate or sequential application to plant propagation material.

Said another object is also related to a use of acibenzolar-S-methyl in a seed treatment composition, for inducing resistance against insect-vectored, preferably aphids or leafhooper-vecrored, viral infections in a sunflower plant. Said another object is also related to a kit of parts suitable for use in the above-mentioned methods, said kit comprising a plant activator, and a diluent or carrier precursor, for the simultaneous, separate or sequential application to plant propagation material. Said another object is also related to a use of a salicylic acid analogue in a seed treatment composition, preferably acibenzolar, acibenzolar-S-methyl or probenazole, more preferably acibenzolar-S-methyl, for inducing resistance against insect-vectored, preferably aphids or leafhooper-vecrored, viral infections in a sunflower plant. In the methods of said another object, the plant propagation material can be a sunflower seed, and the rate of acibenzolar-S-methyl applied to the plant propagation material can be from 0.25 to 100 g/dt sunflower seed, said sunflower seed being more preferably selected from Helianthus annuus L. or a Helianthus tuberosus L seeds. More preferably, said rate can be selected as follows (1 dt = 100 kg):

- from 0.25 to 50 g /dt sunflower seed;

- from 0.5 to 50 g /dt sunflower seed;

- from 1 to 50 g /dt sunflower seed;

- from 1 to 30 g /dt sunflower seed;

- from 1 to 20 g /dt sunflower seed;

- from 2 to 20 g /dt sunflower seed;

- from 2.5 to 20 g /dt sunflower seed;

- from 2.5 to 10 g /dt sunflower seed;

- from 4 to 10 g /dt sunflower seed;

- from 2.5 to 7.5 g /dt sunflower seed; and

- from 4 to 6 g /dt sunflower seed.

Claims

1. A method of reducing insect-vectored viral infection in a plant, by contacting plant propagation material prior to or during sowing and planting with a seed treatment composition comprising acibenzolar-S-methyl.

2. The method according to claim 1, wherein the plant is a plant from the Grass (Poaceae) family, and wherein the plant propagation material is a cereal crop propagation material.

3. The method according to claim 1 or claim 2, wherein the cereal is a warm season or a cold season cereal.

4. The method according to any one of claims 1 to 3, wherein the cereal crop is selected from the group consisting of millet, maize; corn, sorghum, barley, oats, rice, rye, spelt, teff, triticale, and/or wheat.

5. The method according to claim 4, wherein millet comprises finger millet, fonio, foxtail millet, Japanese millet, kodo millet, pearl millet, and/or proso millet.

6. The method according to any one of claims 1 to 5, wherein the plant is a crop plant selected from wheat, barley, rye, oats and/or rice.

7. The method according to any one of claims 1 to 6, wherein the plant is susceptible to damage by viral infections transmitted by aphid or leafhopper.

8. The method according to claim 7, wherein the virus is Barley yellow dwarf virus (BYDV), preferably transmitted by aphids Rhopalosiphum padi, Sitobion avenae and/or Metopolophium dirhodum.

9. The method according to claim 8, wherein the virus is Wheat dwarf virus (WDV) is transmitted by the leafhopper Psammotettix alienus.

10. The method according to any one of claims 1 to 9, wherein the plant propagation material is treated before its planting, and/or during its planting.

11. The method according to any one of claims 1 to 10, wherein the composition comprising at least acibenzolar-S-methyl is applied as a seed treatment composition, further comprising an agrochemically acceptable diluent or carrier.

12. The method according to claim 11, wherein the plant propagation material is a seed.

13. The method according to claim 12, wherein the seed is a seed of millet, maize, corn, sorghum, barley, oats, rice, rye, spelt, teff, triticale, and/or wheat.

14. A method of protecting a Grass plant against insect-vectored viral diseases by treating the plant propagation material with effective amounts consisting essentially of acibenzolar-S-methyl and an agrochemically acceptable diluent or carrier.

15. An agrochemical seed treatment composition consisting essentially of an effective amount of at acibenzolar-S-methyl, and a carrier or diluent, or a premix for application of the seed treatment in a solid or liquid form.

16. The seed treatment composition according to claim 15, wherein a second and third active ingredient are present in a range of ratios by weight of from 1:1 to 1:50.

17. The seed treatment composition according to claim 16, wherein the acibenzolar-S-methyl, and the first and second active ingredient or a second and third active ingredients are present in an amount of from 1: 1:1, to 1:50:150, to 150:50:1.

18. The seed treatment composition according to any one of claims 16 to 17, comprising at least two active ingredient components optionally together with one or more customary formulation auxiliaries, wherein components (I) and (II) include one or more insecticides and one or more fungicides(s) selected from the group consisting of thiamethoxam, oxathiapiprolin, azoxystrobin, cyantraniliprole, ludioxonil, metalaxyl, metaxalyl-M, mefenoxam, azoxystrobin, difenoconazole and/or myclobutanil.

19. Plant propagation material which has been treated with the composition according to any one of claims 16 to 18.

20. A kit of parts suitable for use in the methods of any one of claims 1 to 14, comprising acibenzolar-S- methyl, and a diluent or carrier, or precursor thereof, for the simultaneous, separate or sequential application to plant propagation material.

21. Use of acibenzolar-S-methyl in a seed treatment composition, for inducing resistance against insect- vectored, preferably aphids or leafhooper-vecrored, viral infections in a plant.

22. Use accoding to claim 21, wherein the plant is a Grass (Poaceae) plant.

23. The method of claim 1, wherein the plant propagation material is a cereal seed, and the rate of acibenzolar-S-methyl applied to the plant propagation material is from 0.25 to 100 g/dt cereal seed.

24. The method of claim 23, wherein the rate is selected from:

0.25 - 50 g /dt cereal seed;

0.5 - 50 g /dt cereal seed;

1 - 50 g /dt cereal seed;

1 - 30 g /dt cereal seed;

1 - 20 g /dt cereal seed;

2 - 20 g /dt cereal seed;

2.5 - 20 g /dt cereal seed;

2.5 - 10 g /dt cereal seed;

4 - 10 g /dt cereal seed;

2.5 - 7.5 g /dt cereal seed; and 4 - 6 g /dt cereal seed.

25. The method of claim 23, wherein the rate is selected from 1 to 20 g /dt cereal seed.

26. The method of claim 23, wherein the rate is selected from 2.5 to 10 g /dt cereal seed.

27. The method of any of claims 23-26, wherein the cereal seed is a wheat or barley seed.