AU2019232818A1

AU2019232818A1 - Granular insecticide composition and method for preparation

Info

Publication number: AU2019232818A1
Application number: AU2019232818A
Authority: AU
Inventors: Mathew NEMARIC; Philip Edward Pentland
Original assignee: Farmalinx Pty Ltd
Current assignee: Farmalinx Pty Ltd
Priority date: 2019-09-18
Filing date: 2019-09-18
Publication date: 2021-04-01

Abstract

A broadcast granule composition comprising a core and coatings about the core the coatings comprising (i) a powder coating layer about the core comprising thiamethoxam in the form of a powder in admixture with a powder of a carrier; and (ii) a coating of sticking agent about the powder coating layer.

Description

Granular Insecticide Composition and Method for Preparation Field

This invention relates to a granular composition of the pesticide thiamethoxam, to preparation of the composition and use of the composition to control insect infestations in turf. In particular the invention relates to a broadcast granule composition of thiamethoxam insecticide, that is a granule composition to be applied to soil and/or vegetation by directly spreading the insecticide granule composition onto the soil and/or vegetation.

Background

Thiamethoxam is a broad-spectrum systemic insecticide that acts by interfering with nicotinic acetylcholine receptors in the central nervous system of insects, leading to paralysis and death. The IUPAC name is 3-[(2-Chloro-1,3-thiazol-5-yl)methyl]-5-methyl N-nitro-1,3,5-oxadiazinan-4-imine. Thiamethoxam is an effective group 4a neonicotinoid insecticide that can be used to manage pests such as billbug and African black beetle in lawns and turf.

In conventional practice thiamethoxam may be applied to turf after diluting a concentrate of the insecticide in spray water. Thiamethoxam formulation concentrates may be in the form of water-dispersible granules or aqueous suspension concentrates. These concentrates can be added to spray water and the diluted material can be applied using a boom spray.

The product Meridian (sold by Syngenta for the season-long control of grubs in turf) is a water-dispersible granule containing 250 g/kg of thiamethoxam. The product Columbus Insecticide (sold by Turf Culture) is an aqueous suspension concentrate containing 250g/L of thiamethoxam.

Neonicotinoids such as thiamethoxam are known to be toxic to some beneficial organisms such as some bee species, and the spray application of thiamethoxam may be problematic because of the ease with which bees can contact the neonicotinoid.

The present inventors have sought to develop a broadcast granule composition of the insecticide thiamethoxam but efficient preparation of such granules often requires the use of solvents to dissolve the active agent and allow adsorption onto an inert carrier. The solvent needs to then be removed by heat drying involving removal of organic solvents. Other granulation methods involve application of a coating such as an adhesive or sticker about a carrier onto which the insecticide is applied. The coating often also requires the use of solvents and can lead to handling problems arising from the use of adhesives or viscous materials in granulation equipment.

Thiamethoxam is active at low concentrations which creates particular problems for delivery from a broadcast granule composition. At low concentrations the uniformity of distribution of active between granules of a sample composition becomes important. Ineffective granule formulation with such actives can lead to localised overdosing or under-dosing of the active.

There is a need for broadcast granules of the insecticide thiamethoxam which can readily be prepared and provide effective control of insects, for example in turf management.

Summary of Invention

There is provided a broadcast granule composition comprising a core and coatings about the core, the coatings comprising

(i) a powder coating layer about the core comprising thiamethoxam in the form of a powder in admixture with a carrier powder; and (ii) a coating of sticking agent about the powder coating layer.

In a further embodiment there is provided a process for the preparation of broadcast granules comprising thiamethoxam the process comprising

* providing a dry granule core; * agitating the core in the presence of a powder mixture comprising thiamethoxam powder in admixture with a powder carrier to dry-coat the core with the powder mixture; and blending the dry-coated core with a sticking agent to provide an adhered coating of sticking agent about the powder coated core.

It is preferred that the concentration of thiamethoxam in the total granule composition is in the range 100-20,000 ppm, preferably 300-3000 ppm.

The concentration of thiamethoxam powder in the powder coating admixture is preferably in the range 3 % w/w to 30 % w/w.

The process allows a higher loading of powder mixture to be uniformly immobilised on the surface of the core and a uniform distribution of thiamethoxam between cores of a sample. This can not readily be achieved by methods which involve (i) a first step of adding a sticking agent to the core, and then (ii) adding a powder mixture to the sticky core.

Detailed Description

Throughout the description and the claims of this specification the word "comprise" and variations of the word, such as "comprising" and "comprises" is not intended to exclude other additives, components, integers or steps.

The granular insecticide is suitable to be applied to soil and/or vegetation by directly spreading the insecticide granule composition onto the soil and/or vegetation at a suitable dosage rate. The dry granule composition can generally be applied with a dry spreader or by hand to a target area, such as an area of turf and when exposed to water by way of, for example, rain or irrigation, the pesticide material may migrate away from the carrier.

The flash points reported herein are the Cleveland open cup (COC) flashpoints referred to in ASTM D 92.

Billbugs (Spenophorus brunnipennis) are small beetles that feed on and lay eggs in turfgrass. The larvae do the most damage as they feed on the grass blades and eventually the roots. Billbugs are also called snout beetles and are hard sided beetles which are dark or black in colour. Larvae are white and legless, with darker heads.

Larvae can be found in the crown layer of the turf, and also below the thatch layer. Indications of billbug infestation include leaves that pull out easily, and the presence of hollow stems.

African black beetle (Heteronychus arator) is sometimes called black lawn beetle. It is native to Africa and has been introduced to Australia and the north island of New Zealand. It is a shiny black oval-shaped beetle about 12 -15 mm long.

Grass used in a landscape customarily is referred to as a "lawn" while grass used on a baseball field or golf course is referred to as "turf."

By definition, a lawn is a piece of residential, commercial or industrial land on which grass grows. Turf is the term used by horticulturists referring to grass that is mowed and maintained with the same uses as a lawn.

The terms turf and lawn are used herein to be essentially equivalent and interchangeable.

Common types of grasses used in lawns around Australia include Kikuyu grass, Buffalo grass, Couch grass, Zoysia grass and Tall Fescue.

The granule composition of the invention comprises a core that may comprise fertiliser and a surrounding layer of powder mixture comprising thiamethoxam. The method may be carried out in a rotatable mixing vessel such as a drum, pan or the like or a mixing vessel with an agitator such as a rotating screw, and includes an initial step of adding the core to the mixing vessel; adding to the core a powder mixture that comprises thiamethoxam powder in admixture with carrier powder under agitation to form a primary dry blend, and adding a sticker to the primary dry blend under further agitation.

We have found that the process of the invention comprising blending the dry-coated core with a sticking agent to provide an adhered coating of sticking agent about the powder coated core provides a significant improvement when compared with a corresponding process of first adding sticker to the core and then adding the powder mixture to the sticky core. Without wishing to be bound by theory, it is believed that the formation of the primary blend in the instant invention may involve an electrostatic affinity between the surface of the granule core and the surface of the carrier powder that includes thiamethoxam powder, leading to a substantially uniform dry-coated layer of carrier powder around the core. The electrostatic forces provide a relatively uniform layer of powder mixture including the thiamethoxam powder which becomes locked in place on application of the sticking agent.

Without wishing to be bound by theory, it is further believed that when the core of the invention are dry-coated with powder mixture including thiamethoxam powder, the interstitial spaces between the powder particles of the dry coating have capillary character which efficiently soaks up post-added sticking agent into the region proximal to the surface of the core. This efficient deposition of sticking agent does not occur when the sticking agent is applied to the core before the carrier powder is added.

The process is particularly effective when the core is a fertiliser.

In a further aspect there is provided a method of controlling insects such as billbug and African black beetle in turf, the method comprising applying the granule composition to an area of turf.

Lawn management activities are considerably improved by the formulations of the invention. The core may be chosen so that it provides a benefit for turf management (e.g. soil amendment, soil fertiliser) and the association between the core and the insecticide thiamethoxam enables a double benefit to be obtained in a single product application. Broadcast granules rely on a water through rain or watering-in by spraying of water using a hand held spray or irrigation. Where a watering-in step is used for fertiliser and also for insecticide, the formulation of the invention enables a single watering-in step (rather than multiple such steps) to be used, with savings in water utilisation and fuel. Furthermore irrigation programming is simplified.

The handling and application of a granule composition comprising the coating of a low concentration of thiamethoxam insecticide is also easier and safer than the handling and application of a concentrated formulation of thiamethoxam fertiliser.

Compared with the tank-mixed spray application of fertiliser and insecticide, more fertiliser can be applied using a formulation of the invention wherein the core is a fertiliser. This means that the fertilisation benefit is more sustained. Furthermore the use of granule composition (as distinct from tank mixes) leads to reduced off-target damage (e.g. no spray drift), and the problem of poor tank-mix compatibility does not arise.

In one embodiment of the invention the core comprises inert carrier materials e.g. clay or mineral materials. The core may be prepared by crushing, attrition or other comminution methods, or by agglomeration of smaller particles.

In one embodiment of the invention the core comprises a fertiliser that may comprise a single nutrient or a composite of various nutrients. Nutrients that may be used in the invention include ammonium nitrate, ammonium sulfate, ammoniated superphosphate, ammonium chloride, monoammonium phosphate, diammonium phosphate, calcium cyanamide, calcium nitrate, urea guanidine, guanidine nitrate, nitro guanidine, superphosphate, triple superphosphate, potassium nitrate, potash, potassium chloride, potassium sulfate, potassium metaphosphate, urea, urea phosphate and mixtures or combinations thereof. Those of skill in the art will appreciate that other fertilisers may be used in the methods and systems described herein.

In another particular aspect, the core comprises fertiliser that has at least one of nitrogen (N), phosphorous (P), potassium (K), NPK, NP, NK and PK. These elements may be combined in different ratios. For example in one aspect the NPK ratios may be 13-13-13 , or 27-0-0, or 12-50-0, or 0-0-50, or 21-7-14, or 15-15-15, 10-11-18, or 16-6-8. Other ratios of NPK will be evident to those of skill in the art.

Suitable fertiliser materials for use as a core in the invention include NPK-type fertilisers which may include methylene urea nitrogen sources, phosphorous sources, single superphosphates, triple superphosphates, calcium phosphates, nitro phosphates, potassium phosphates, ammonium phosphates, ammoniated superphosphates and the like and mixtures thereof. Further fertiliser granules suitable for use in the methods of the invention include potassium sources such as muriate of potash, potassium sulfates, potassium phosphates, potassium hydroxides, potassium nitrates, potassium carbonates, potassium bicarbonates, potassium magnesium sulfates and the like and mixtures thereof.

In another particular aspect, the fertiliser core may contain secondary nutrients such as sulfur, magnesium, and calcium and/or micronutrients such as iron, manganese, zinc, copper, molybdenum, boron and cobalt.

Additional fertiliser granules suitable for use as core component of granule composition of the invention include secondary nutrient sources such as elemental sulfur, calcium and magnesium salts including phosphates, oxides, sulfates, carbonates, chlorides, nitrates and the like and mixtures thereof. Still further fertiliser granules suitable for use in the methods of the invention include micronutrient sources such as iron, manganese, copper, boron, zinc and molybdenum salts such as phosphates, oxides, sulfates, carbonates, chlorides, nitrates, borates, molybdates and the like and mixtures thereof as well as chelates of micronutrients such as EDTA, amine polycarboxylates, glucuronates and the like.

Representative materials that may be used as dry micronutrient substrates in the core of the present invention include calcium nitrate, magnesium sulfate, magnesium nitrate, ferrous sulfate, ferrous nitrate, manganese sulfate, manganese nitrate, copper sulfate, copper nitrate, boric acid, borates, sodium borate, zinc sulfate, zinc nitrate, sodium molybdate, ammonium molybdate and the like.

The core may contain further active pesticides such as selected from the group of fungicides, insecticides and herbicides.

The fertiliser granule that may be used as the core component of the granule composition can be a coated fertiliser granule or an uncoated fertiliser granule. The coated or uncoated fertiliser core may be coated with thiamethoxam powder mixture in accordance with the invention.

The fertiliser granule that may be used as the core component of the granule composition of the invention may be of a controlled release type known in the industry. In a further embodiment the core used in the composition and process of the invention may comprise a mixture of coated and uncoated fertiliser granules.

The fertiliser granule that may be used to form the core of the granule composition may provide for the controlled release of fertiliser, in which case said core fertiliser granule will typically have a controlled release coating around the granule. The coating may be a partial coating, but it is preferred that the core fertiliser granule will have a complete coating providing controlled release. The fertiliser granule coating may contain a mixture of impervious and porous or water-soluble materials. The fertiliser granule coating may be a suitable controlled release coating material such as a sulfur coating, a polymer coating such as a thermosetting or thermoplastic polymer or other suitable coating for providing controlled release of the fertiliser.

The sticking agent may be a range of materials. Preferred sticking agents are viscous materials and thermoplastic polymers. It is a particular advantage of preferred aspects of the invention that the sticking agent can be used without the need for volatile solvents or aqueous carrier to bind the carrier powder to the core.

Examples of suitable thermoplastic and high viscosity materials include stearamide; polyolefins such as polyethylene, oxidized polyethylene, polypropylene, polyisobutylene, styrene-based polymer; polyolefin (block) copolymers; polyesters; polyesters (block) copolymers; polyethers, such as polyethylene oxide, polypropylene oxide; polyether (block) copolymer; vinyl resin such as polyvinyl acetate, polyvinyl alcohol, polyvinyl chloride, polyvinylidene chloride, polyvinyl pyrrolidone, polyvinyl acetal, polyvinyl methyl acetamide; acrylic polymers; cellulose derivatives such as cellulose acetate; polyamides; polyamines; polyimides; polycarbonates; polysulfones; polysulfides; polysaccharides and blends of two or more thereof.

Preferred are polyolefins, such as polyethylene, polypropylene, polybutene and the like, polystyrene, polyvinyl acetate, polyvinyl chloride, polyvinylidene chloride, polyacrylate, polymethyl (meth)acrylate, polyacrylonitrile, a polyvinyl ether, a polyvinyl ketone, a diene polymer, a copolymer of selected monomers, or a mixture of these polymers.

Representative examples of diene polymer include a butadiene polymer, an isoprene polymer, a chloroprene polymer, a butadiene-styrene copolymer, an ethylene-propylene diene copolymer, styrene-isoprene copolymer and the like.

Representative examples of olefin copolymers include ethylene-propylene copolymer, butene-ethylene copolymer, butene-propylene copolymer, ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer, ethylene-acrylate-copolymer include, ethylene-methacrylic acid copolymer, ethylene-meth acrylate copolymer, ethylene-vinyl acetate-carbon monoxide copolymer and the like.

Representative examples of copolymers of vinyl chlorides include vinyl chloride-vinyl acetate copolymer and vinylidene chloride-vinyl chloride copolymer.

In addition to the above-mentioned vinyl resins, one or more kinds of other coating materials can be used including polyesters such as polycaprolactone, waxes, natural resins, fats and oils, and modified products of these. Representative examples of waxes include beeswax, Japan wax, paraffin and the like. Examples of natural resins include natural rubber, rosin and the like. Representative examples of fats and oils and modified products of these include hydrogenated oils, solid or semi-solid fatty acids, metal salts thereof, or the like.

Thermoplastic resins may be chosen from polyamide (PA or nylon), polyesters such as polybutylene terephthalate (PBT) and polyethylene terephthalate (PET), polycarbonate (PC), polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC), or combinations.

In a preferred embodiment the sticking agent is a high viscosity material, preferably having a Kinematic viscosity of at least 200 (and preferably at least 300, more preferably at least 400) centistokes (cSt) at 40 0C such as from 400 cSt to 250,000 cSt. The highly viscous material will have a reduced viscosity at higher temperature such as a viscosity of no more than 10,000 cSt at 1000 C preferably no more than 5,000 cSt at 1000 C such as 10 cSt to 10,000 cSt or 10 to 5,000 cSt.

The more preferred sticking agent is polybutene and in particular polybutene of molecular weight (Mn) from 400 to 3000. Examples of specific grades of polybutene and their physical properties are provided in Table 1.

Table 1

Item Unit PB450 PB680 PB950 PB1300 PB1400 PB2400

Molecular weight Mn 450 680 950 1300 1400 2450

Kinematic Viscosity 400 C cSt 190 1,700 7,200 22,000 27,000 206,000

1000 C cSt 14 80 230 645 810 4,700

Flash Point (COC) °C 160 175 210 220 230 260

Pour Point °C -31 -14 0 3 5 17 Density @250 C g/cm3 0.854 0.874 0.890 0.896 0.899 0.906

Color APHA 15 15 15 15 15 15 Density @250 C wt% 0.7 0.64 0.18 0.11 0.10 0.05

Loss on Heating mgKOH/g 0.01 0.01 0.01 0.01 0.01 0.01 Water Content Ppm 30 30 30 30 30 30

The most preferred sticking agent is polybutene of molecular weight (Mn) 400 to 1400, particularly polybutene of molecular weight (Mn) 1300.

In one embodiment of the invention, the process of the invention involves heating the thermoplastic polymer or viscous material to reduce the viscosity on contact of the sticking agent with the mixture of carrier powder and thiamethoxam powder that dry coats the core. The temperature to which the sticking agent is heated will depend on the specific sticking agent and the properties optimal for providing a coating of the sticking agent on the mixture of carrier powder and thiamethoxam powder that dry-coats the core. In one embodiment the sticking agent is heated to a temperature in the range of

40 0C to 130 0C such as 400 C to 800 C or 500 C to 800 C. The sticking agent may be heated to a temperature sufficient to provide a Kinematic viscosity of no more 30,000 cSt such as from 1 cSt to 30,000 cSt or from 1 cSt to 10,000 cSt such as 1 cSt to 5000 cSt or 1 cSt to 2000 cSt.

The carrier powder may comprise material selected from the group consisting of relatively water-insoluble materials such as silicon dioxide, gums, insoluble metal oxides, minerals, bentonite, perlite, talc, kaolin, aluminum silicate, diatomaceous earth, attapulgite, barium sulfate, mica, calcium carbonate, precipitated silicates, aluminum silicate, zeolites and mixtures thereof. In one embodiment the ratio of thiamethoxam powder to carrier powder is at least 1:40, preferably at least 1:20, more preferably about 1:10. In one embodiment the ratio of thiamethoxam powder to carrier powder is no greater than 2:1, preferably no greater than 1:2, more preferably no greater than 1:3.

The carrier powder of the invention may comprise powdered porous carriers such as porous silica or diatomaceous earth or other powder porous materials, and at least some of these porous materials may be loaded with bioactive materials such as herbicides or fungicides.

The carrier powder of the invention may comprise herbicides such as one or more selected from the group consisting of foramsulfuron, halosulfuron-methyl, iodosulfuron methyl-sodium, rimsulfuron, trifloxrsulfuron sodium, prosulfuron, dicamba, bromoxynil, MCPA, dithiopyr, oryzalin, pendimethalin, prodiamine, propyzamide, diflufenican, clopyralid, oxadiazon, dicamab, quinclorac, endothal, ethofumesate, disodium methylarsonate, isoxaben, monosodium methylarsonate, bentazone, glufosinate ammonium, MSMA, mecoprop, 2,4-D, bispyribac, metolachlor, endothal, propyzamide, oxadiazon, halosulfuron, carfentrazone-ethyl, clopyralid, diflufenican, indaziflam and glyphosate.

In one preferred embodiment the carrier powder comprises oxadiazon.

In one embodiment the carrier powder comprises oxadiazon, and the ratio of thiamethoxam powder to oxadiazon powder is at least 1:40, preferably at least 1:30, more preferably at least 1:20. In one embodiment the carrier powder of the invention comprises oxadiazon, and the ratio of thiamethoxam powder to oxadiazon powder is no more than 1:2, preferably no more than 1:4.

In the case where a herbicide such as oxadiazon is used as part or all of the carrier powder, the advantages of using a formulation of the invention for turf management are more pronounced. In addition to providing a benefit associated with the core, and a benefit associated with the insecticide thiamethoxam, there is a further benefit associated with weed control that can be achieved with the herbicide such as oxadiazon. It is known that in spring and autumn, weed germination and insect pressure can occur at similar times. Key turf grasses that get a lot of billbug activity (e.g. kikuyu) can derive particular benefit from a formulation that provides deterrence and/or control of weeds and insects. The savings in application costs and watering-in costs are particularly pronounced for formulations that include fertilizer, insecticide and herbicide components.

The core of the granule composition may be a granule such as a fertilizer granule of size from 0.5mm to 10mm, such as 1mm to 5mm. The specific dimensions of the granule are not narrowly specific and may depend on the method by which granules are formed, such as by prill formation, pan granulation, extrusion, tableting and so forth. Granules formed by extrusion may be given a tumbling treatment, for example in a spheroniser.

The mixing of thiamethoxam powder and carrier powder may be carried out using any method of powder blending known to the art such as mixing in a high-speed or low speed mixer. The weight ratio of thiamethoxam powder to carrier powder may be at least 3%, preferably at least 5%, more preferably at least 8%. The weight ratio of thiamethoxam powder to carrier powder may be no more than 50%, preferably no more than 30%, more preferably no more than 15% w/w.

The thiamethoxam powder may have an average diameter of no more than 150 microns, such as no more than 100 microns, such as 1 to 100 microns. In one embodiment the D(v,0.9) value of the thiamethoxam powder particle size distribution is less than 50 microns, preferably less than 30 microns, more preferably less than 20 microns. D(v,0.9) is that particle diameter such that the cumulative volume (or mass) of those powder particles in the distribution with a lower diameter than D is 90% of the sample.

The carrier powder may have an average diameter of no more than 150 microns, such as no more than 100 microns, such as 1 to 100 microns. In one preference the D(v,0.9) value of the carrier powder particle size distribution is less than 50 microns, preferably less than 30 microns, more preferably less than 20 microns.

The weight proportion of carrier powder plus thiamethoxam powder in the final granule may be at least 0.3%, preferably at least 0.5%, more preferably at least 0.8%.

The weight proportion of carrier powder plus thiamethoxam powder in the final granule is no more than 5%, preferably no more than 3%, more preferably no more than 2%.

The method of the invention may generally be conducted in a single mixing vessel such as a rotating drum or pan mixing vessel or a mixing vessel with an agitator such as a rotating screw despite the use of viscous or thermoplastic sticking agent. In single vessel processing, there is a higher tendency for the viscous material to generate clumps or balls of coated materials, and to deposit on the walls of the vessel. The method of the invention significantly reduces these problems allowing the process to be conducted in a single vessel if desired. Single vessel operation was previously regarded as unsuitable for highly viscous materials such as used in the preferred embodiment of the method of the invention. It is thus a particular advantage of the invention that it allows the use of viscous materials without volatile solvents. Volatile solvents often required in previous methods of coating granules are more hazardous to handle and transport and require additional infrastructure and expense to meet regulations for handling such materials.

The present inventors have found that the core component of the invention can be (i) dry-coated with carrier powder mixed with thiamethoxam powder and then (ii) blended with viscous coating materials, preferably without the use of volatile solvents. The inventors have also found that non-viscous stickers such as mineral oil are problematic in making the granules of the invention because fine particles from the powder coating tend to become dislodged during granule handling and storage. Without wishing to be bound by theory, it is believed that granule handling leads to the creation of new capillary spaces, and that low-viscosity stickers such as mineral oil may be drawn into these freshly created spaces, and are so become less effective in sticking powder to the underlying core.

The sticking agent in the form of a viscous material and/or thermoplastic polymer may have a flash point of at least 160C, preferably at least 2000 C and no significant content of volatiles is required.

The viscous material and/or thermoplastic polymer may have a flash point of at least 160 0C, preferably at least 2000 C, and no volatile component is required.

As previously mentioned, the process allows the use of volatile aqueous carriers such as latex or emulsion compositions to be avoided. Generally speaking, the sticking agent will comprise no more than 5% w/w water such as no more than 3% w/w water.

In one embodiment the sticking agent may be applied at elevated temperature to a room temperature dry-coated core.

Suitable sizes of components and proportions may be chosen having regard to the composition and method described without undue experimentation.

The fertiliser core may, for example have an average diameter 1mm to 5mm.

The carrier powder may, for example, have an average diameter no more than100 microns.

The thiamethoxam powder may, for example, have an average diameter of no more than 100 microns.

The amount of carrier powder plus thiamethoxam powder may, for example be about 3g/kg to 80g/kg, preferably 6g/kg to 20 g/kg, of the granule composition.

The amount of volatile material in the formulation is preferably no more than 4% and preferably no more than 2% w/w of the granule composition.

The amount of sticking agent in the formulation may, for example, be about 1 g/kg to about 10 g/kg, preferably 1.5g/kg to 6g/kg, of the granule composition.

The weight ratio of thiamethoxam powder to carrier powder may be 1:30 to 2:1, preferably in the range 1:15 to 1:2, more preferably in the range 1:15 to 1:5, such as about 1:10.

In one embodiment the weight ratio of carrier powder plus thiamethoxam powder to viscous sticking agent is greater than 1:2, preferably greater than 1:1, more preferably greater than 2:1, even more preferably greater than 3:1.

In one embodiment the weight ratio of carrier powder plus thiamethoxam powder to viscous sticking agent is no more than 30:1, preferably no more than 20:1, more preferably no more than 10:1, even more preferably no more than 6:1.

The granules are prepared by a process in which the mixture of carrier powder and thiamethoxam powder is contacted with the core granules to coat the core granules with the powder. The core granules may be tumbled in a rotating vessel such as a drum or pan or a mixing vessel with an agitator such as a rotating screw, to provide intimate contact of the core granules with the mixture of carrier powder and thiamethoxam powder and take advantage of the generated electrostatic forces which are believed to be at least partly responsible for efficiency of this process. The mixture of carrier powder and thiamethoxam powder is generally combined with the fertiliser granules over a period of time to provide a gradual build-up of the powder on the granules. For example the powder may be added to the granules over a period of from 5 minutes to two hours such as from 5 minutes to one hour, five minutes to 30 minutes or the like. Alternatively the powder can be added in small discrete portions over time, such as 2, 3, 4, 5, or greater number of portions.

The sticking agent is heated to reduce the viscosity of the sticking agent to a suitable temperature at which the viscosity is reduced to a Kinematic viscosity such as no more than 30,000 cSt, no than 10,000 cSt or from 1 cSt to 10,000 cSt such as 1 cSt to 5000 cSt or 1 cSt to 2000 cSt. The temperature may, for example be in the range of 400 C to 130 0C such as 40 0C to 80 0C or 50 0C to 80 0C. The hot sticking agent is added to the dry coated core over a period of time to build a coating about the mixture of carrier powder and thiamethoxam powder which coat the core of the granules. For example the hot sticking agent may be added to the powder coated core granules of fertiliser over a period of from 5 minutes to two hours, such as from 5 minutes to one hour, five minutes to 30 minutes or the like.

On cooling the sticking agent forms a more viscous semi-solid or solid coating allowing the granules to flow and separate in the rotating vessel or a mixing vessel with an agitator such as a rotating screw.

The core fertiliser may comprise a sustained release fertiliser such as an encapsulated granule.

In a further embodiment the core may have an NPK ratio preferably around 16-6-8. For example the product "Turf Supreme" 16-6-8 sold by Simplot.

The sticker is preferably chosen from low-volatile resins, such as viscous low-volatile resins, preferably polybutenes, more preferably polybutene PB1300 (<0.2% volatile), PB450, PB 680, PB950 or mixtures of two or more thereof.

The process preferably includes heating of the sticker before addition to the mixing vessel, preferably to a temperature in the range 40 to 700 C.

In a particularly preferred set of embodiments:

the fertiliser cores have an average diameter between 3mm and 4mm;

the carrier powder substantially comprises oxadiazon powder and has an average diameter 20 microns;

the thiamethoxam powder has an average diameter no more than 20 microns;

the amount of oxadiazon plus thiamethoxam powder on a weight/weight basis in the formation is between about 5g/kg and 80g/kg and preferably between 6g/kg and 20 g/kg;

the amount of volatile material in the formulation is less than 4% and preferably less than 2%;

the sticking agent comprises polybutene in an amount of from about 1 g/kg to about 5 g/kg; and the ratio of thiamethoxam powder to oxadiazon powder is in the range from 1:20 to 1:4, such as about 1:10.

In a preferred embodiment the method of the invention comprises:

• mixing the core with a powder comprising thiamethoxam powder and carrier powder for a period of at least 1 minute, preferably at least 5 minutes such as at least 10 minutes or about 15 minutes to coat granules with a composition which includes thiamethoxam powder and carrier powder that optionally includes a further active, particularly oxadiazon. Care may be taken to avoid loss of active as dust. • adding heated sticker gradually over a period of at least 1 minute, preferably at least 5 minutes, such as at least 10 minuted or about 15 minutes; and • blending the sticker and powder coated core, preferably for at least 10 minutes, preferably at least 20 minutes such as 30 minutes.

In one embodiment, the carrier powder comprises a herbicide, which may be a turf herbicide, such as oxadiazon. Oxadiazon may comprise at least 50wt% of the carrier powder such as at least 70wt%, at least 80 wt% or substantially all of the carrier powder.

Lawn management activities are particularly improved by the formulations of the invention when the core is a fertiliser granule, and when the powder carrier for the thiamethoxam is substantially oxadiazon herbicide.

Such formulations provide a triple benefit of soil nutrition, control of insects and control of emerging weeds, to be obtained in a single product application. Where a watering-in step is required for fertiliser and also for herbicide and insecticide, the formulation of the invention enables a single watering-in step (rather than multiple such steps) to be used, with savings in water utilisation and fuel. Furthermore irrigation programming is considerably simplified.

The handling and application of a granule that has been coated with a low level of thiamethoxam insecticide is easier and safer than the handling and application of a concentrated formulation of thiamethoxam fertiliser.

Compared with the tank-mixed spray application of fertiliser and insecticide, more fertiliser can be applied using a formulation of the invention wherein the core is a fertiliser. This means that the fertilisation benefit is more sustained. Furthermore the use of granules (as distinct from tank mixes) leads to reduced off-target damage (e.g. no spray drift), and the problem of poor tank mix compatibility does not arise.

The invention will now be described with reference to the following examples. It is to be understood that the examples are provided by way of illustration of the invention and that they are in no way limiting to the scope of the invention.

Examples

The following compositions of granules of the invention were made:

Examples 1 and 2 (El, E2,): Compositions based on a core component comprising soil amendment agent calcium carbonate (El) and the fertiliser granule Turf Supreme 16-6-8 (E2). Fertiliser granule is sold by Simplot Partners and has the following minimum analysis:

Total nitrogen (16%, as ammoniacal nitrogen), available phosphate acid (P, 6%), soluble potash (K 20, 8%), sulfur (S, 16%), Iron (Fe, 1.5%), Manganese (Mn, 0.2%).

El: Fertiliser granule with 1g/kg of thiamethoxam

Component CAS number Grams per kg

Carrier (kaolin) 10.5

Thiamethoxam (98%) 153719-23-24 1.02

Carrier + thiamethoxam (fine- (11.52) powder coating)

Polybutene PB 1300 9003-27-4 2.9

Calgrit prills (core) Contain >95% calcium carbonate, 986.165 sold by Ixom Australia.

E2: Fertiliser Granule with 1g/kg of thiamethoxam

Component CAS number Grams per kg

Carrier oxadiazon (95%) 19666-30-9 10.5

Thiamethoxam (98%) 153719-23-4 1.02

Carrier + thiamethoxam (fine- (11.52)

powder coating)

Polybutene PB 1300 903-27-4 2.9

Turf Supreme granules with Sold by Simplot Partners 985.855 NPK 16-6-8 (core)

1000

Formulation E2 was used in field trials for insecticide activity (see below).

Example 3: Process example (for formulation E2)

Equipment

• Vrieco Nauta Mixer NX Type (conical screw) • Stainless steel collection trays

Formulation process

A typical manufacturing batch size is 1,000kg.

Step 1. Fill the Nauta mixer with all the required Turf Supreme granules. Turn the mixer on at a medium speed.

Step 2. Blend the carrier (oxadiazon) and thiamethoxam powders to achieve a uniform mixture.

Note: Ensure the oxadiazon and thiamethoxam technical (mixture) has a particle size distribution of D(v,0.9) <20pm.

Step 3. Gradually add oxadiazon/thiamethoxam to the mixing vessel and mix for at least 10 minutes or until all granules are uniformly coated.

Note 1. Heat the polybutene until a pourable consistency is achieved to aid with addition and coating.

Step 4. Very gradually add the hot Polybutene PB1300 to the granules while mixing. Mix for at least 1 hour or until all granules are evenly coated and no lumps remain. The product can then be emptied into stainless steel collection trays and be packed off.

Note 2. Limit contact of granules with multiple surfaces after removal from Nauta mixer as the granules are slightly tacky and active material can be removed.

Example 4: Bioefficacy

Two Insect field trials FT1, and FT2 were established to assess insecticide control of billbug (Spenophorus brunnipennis) and African black beetle (Heteronychus arator) respectively. The objective of the study was to assess the efficacy and safety of insecticide formulations of the invention for controlling billbug and African black beetle on couch grass (Cynodon dactylon) and kikuyu (Pennisetum clandestinum).

The treatments applied in the trial were as follows:

TO: Untreated T1: Commercial WDG of thiamethoxam at 200g active / ha. (800g/ha of formulation) T2: Commercial WDG of thiamethoxam at 300g active / ha. (1200 g/ha of formulation) T3: Formulation E2 of the invention applied at a rate of 200g active/ha (200kg/ha of formulation) T4: Formulation E2 of the invention applied at a rate of 300g active/ha (300 kg/ha of formulation.

The commercial WDG of thiamethoxam was a 250g/kg WDG (water dispersible granule, trade name Meridian 25, sold by Syngenta), and formulation E2 of the invention was as described in experiment 1 above (1g thiamethoxam/kg coated granule).

Soil Description:

FT1 FT2

Location fairway rough sporting oval

Soil Type Sandy Clay Loam Clay Loam

pH 6.6 6.1

OM(Walkley Black 1.2% 1.8%

Method)

Moisture - Soil Dry Adequate profile

Fertility Low Moderate

Drainage Average Average

Turf Species Couch (Cynodon dactylon) Couch (Cynodon dactylon) and Kikuyu (Pennisetum clandestinum).

Trial Design Plot Width 2m

Plot Length 2m

Area of each plot 4m 2

Buffers 0.5m

Replication 4

Plot Design Randomised Complete Block (RCB)

Target Pest

Location Common Name Scientific Name Population Turf Types

Billbug Spenophorus High Couch Grass FT1 brunnipennis (Cynodon dactylon)

FT2 Couch Grass African Black (Cynodon dactylon) +

Heteronychus arator Moderate Beetle Kikuyu (Pennisetum

clandestinum)

Treatment Method

Type Hand held pressurised boom spray

Nozzle size XR11004

Nozzle spacing's 50cm

Droplet size Medium

Swath Im

Pressure 200kpa

Speed im/sec or 3.6 km/h

Water Volume 430L/Ha

Boom Height 50cm above ground level at a spray angle of 110°

Application Details

Treatment Details FT1 FT2

Season summer summer

Time 4:30pm 7:00am

Air Temp 22.6°C 26.2°C

Soil Temp 24.4°C 24.7°C

Relative Humidity 63% 82%

Cloud Cover 40% 40%

Wind Speed 10km/h SE 4km/h N

Rainfall 1.4mm Omm

*All treatments irrigated with 12mm of water post application.

Assessment Techniques

Assessment Timi Method

ng

Phytotoxicity Weekly for the first 4 Visual rating scale of 0- 10, 0 being no phyto observed & 10

weeks. being total death of turf. Provide photographs of key

results.

Efficacy Monthly for 4 months Insect counts per plot via destructive sampling. Use a post treatment. minimum of 4 x 100mm plugs per plot.

FT1: Billbug Larvae Percentage Change

TREATMENT RC 1MAT RC 2MAT RC 3MAT RC 4MAT

UNTREATED 41.67 29.17 75.00b 68.75b

E2 @200KG/HA -8.13 -30.42 -45.00a -51.67a

E2 @300KG/HA -9.72 -34.72 -40.28a -68.06a

MERIDIAN @800G/HA -31.04 -39.17 -55.83a -72.29a

MERIDIAN @1.2KG/HA -39.88 -54.17 -85.71a -85.71a

LSD(p<0.05) ns ns 57.78 59.85

Index

* Letters indicate level of significance. Treatments with differing letter designations indicate a difference in relative change on the parameter in question. * ns = no significant difference at a 95% Confidence Interval. • MAT = months after treatment.

FT1: Phytotoxicity and Crop Tolerance

TREATMENT 4/01/2 11/01/2 18/01/2 25/01/2 1/02/2 018 018 018 018 018 UNTREATED 10.00 10.00 10.00 10.00 10.00

E3 @200KG/HA 10.00 10.00 10.00 10.00 10.00 E3 @300KG/HA 10.00 10.00 10.00 10.00 10.00

MERIDIAN @800G/HA 10.00 10.00 10.00 10.00 10.00 MERIDIAN @1.2KG/HA 10.00 10.00 10.00 10.00 10.00 LSD (p<0.05) ns ns ns ns ns

FT2: African Black Beetle Larvae Presence African Black Beetle Larvae Percentage Change

TREATMENT RC 1MAT RC 2MAT RC 3MAT RC 4MAT UNTREATED 16.67 112.50c 91.67c 116.67b

E2 @200KG/HA -19.58 -48.33ab -56.67ab -69.17a E2 @300KG/HA -22.14 -69.29a -82.86ab -82.86a

MERIDIAN @800G/HA -6.25 -53.75ab -61.25ab -78.75a MERIDIAN @1.2KG/HA -17.50 -65.00a -90.00a -95.00a LSD (p<0.05) ns 69.59 58.09 61.04

Index * Letters indicate level of significance. Treatments with differing letter designations indicate a difference in relative change on the parameter in question.

ns = no significant difference at a 95% Confidence Interval.

FT2: Phytotoxicity and Crop Tolerance.

TREATMENT 19/12/2 26/12/2 2/01/2 9/01/2 16/01/2 017 017 018 018 018 UNTREATED 10.00 10.00 10.00 10.00 10.00

INS-ADA-011 @200KG/HA 10.00 10.00 10.00 10.00 10.00

INS-ADA-011 @300KG/HA 10.00 10.00 10.00 10.00 10.00

MERIDIAN @800G/HA 10.00 10.00 10.00 10.00 10.00

MERIDIAN @1.2KG/HA 10.00 10.00 10.00 10.00 10.00

LSD (p<0.05) ns ns ns ns ns

Index 0 ns = no significant difference at a 95% Confidence Interval.

Summary of Results from FT 1 and FT 2:

At trial completion of FT1, Billbug larvae percentage control was equal between E2 and Meridian 25, and both formulations were superior to the untreated control.

At trial completion of FT2, African black beetle larvae percentage control was equal between E2 and Meridian 25, and both formulations were superior to the untreated control.

Claims

The claims defining the invention are as follows:

1. A broadcast granule composition comprising a core and coatings about the core the coatings comprising

(i) a powder coating layer about the core comprising thiamethoxam in the form of a powder in admixture with a powder of a carrier; and (ii) a coating of sticking agent about the powder coating layer.

2. The broadcast granule composition of claim 1, wherein the concentration of thiamethoxam in the total granule composition is in the range 100-20,000 ppm, preferably 300-3000 ppm

3. The broadcast granule composition of any one of the previous claims, wherein concentration of thiamethoxam powder in the powder coating admixture is in the range 3% w/w to 30 % w/w.

4. The broadcast granule composition of any one of the previous claims, wherein the core is a fertiliser.

5. The broadcast granule composition of any one of the previous claims, wherein the core is a controlled release fertiliser, having a controlled release coating around the core.

6. The broadcast granule composition of any one of the previous claims, wherein the coating of sticking agent comprises at least one sticking agent selected from the group consisting of stearamide; polyolefins such as polyethylene, oxidized polyethylene, polypropylene, polyisobutylene, styrene-based polymer; polyolefin (block) copolymers; polyesters; polyesters (block) copolymers; polyethers, such as polyethylene oxide, polypropylene oxide; polyether (block) copolymer; vinyl resin such as polyvinyl acetate, polyvinyl alcohol, polyvinyl chloride, polyvinylidene chloride, polyvinyl pyrrolidone, polyvinyl acetal, polyvinyl methyl acetamide; acrylic polymers; cellulose derivatives such as cellulose acetate; polyamides; polyamines; polyimides; polycarbonates; polysulfones; polysulfides; polysaccharides and blends of two or more thereof.

7. The broadcast granule composition of any one of the previous claims, wherein the coating of sticking agent comprises at least one sticking agent selected from the group consisting of polyolefins, such as polyethylene, polypropylene, polybutene and the like, polystyrene, polyvinyl acetate, polyvinyl chloride, polyvinylidene chloride, polyacrylate, polymethyl (meth)acrylate, polyacrylonitrile, a polyvinyl ether, a polyvinyl ketone, a diene polymer, a copolymer of selected monomers, or a mixture of these polymers.

8. The broadcast granule composition of any one of the previous claims, wherein the coating of sticking agent comprises polybutene having a Kinematic viscosity of at least 200 centistokes (cSt) at 400 C.

9. The broadcast granule composition of any one of the previous claims, wherein the coating of sticking agent comprises polybutene having and a Kinematic viscosity of at least 300, centistokes (cSt) at 400 C

10. The broadcast granule composition of any one of the previous claims, wherein the coating of sticking agent comprises polybutene having and Kinematic viscosity of 400 cSt to 250,000 cSt at 1000 C.

11. The broadcast granule composition of any one of the previous claims, wherein the coating of sticking agent comprises polybutene having no more than 10,000 cSt at 1000 C preferably no more than 5,000 cSt at 100°C

12. The broadcast granule composition of any one of the previous claims, wherein the coating of sticking agent comprises polybutene of molecular weight (Mn) from 400 to 3000.

13. The broadcast granule composition of any one of the previous claims, wherein the the carrier powder of the invention comprises one or more materials selected from the group consisting of silicon dioxide, gums, insoluble metal oxides, minerals, bentonite, perlite, talc, kaolin, aluminum silicate, diatomaceous earth, attapulgite, barium sulfate, mica, calcium carbonate, precipitated silicates, aluminum silicate and zeolites.

14. The broadcast granule composition of any one of the previous claims, wherein the ratio of thiamethoxam powder to carrier powder is no less than 1:40.

15. The broadcast granule composition of any one of the previous claims, wherein the ratio of thiamethoxam powder to carrier powder is no less than 1:20.

16. The broadcast granule composition of any one of the previous claims, wherein the ratio of thiamethoxam powder to carrier powder is no greater than 1:3.

17. The broadcast granule composition of any one of the previous claims, wherein the carrier powder comprises one or more herbicides selected from the group consisting of foramsulfuron, halosulfuron-methyl, iodosulfuron-methyl-sodium, rimsulfuron, trifloxrsulfuron sodium, prosulfuron, dicamba, bromoxynil, MCPA, dithiopyr, oryzalin, pendimethalin, prodiamine, propyzamide, diflufenican, clopyralid, oxadiazon, dicamab, quinclorac, endothal, ethofumesate, disodium methylarsonate, isoxaben, monosodium methylarsonate, bentazone, glufosinate-ammonium, MSMA, mecoprop, 2,4-D, bispyribac, metolachlor, endothal, propyzamide, oxadiazon, halosulfuron, carfentrazone ethyl, clopyralid, diflufenican, indaziflam foramsulfuron and glyphosate.

18. The broadcast granule composition of any one of the previous claims, wherein the carrier powder comprises oxadiazon.

19. The broadcast granule composition of any one of the previous claims, wherein the carrier powder of the invention comprises oxadiazon, and the ratio of thiamethoxam powder to oxadiazon powder is greater than 1:40 and less than 1:4.

20. The broadcast granule composition of any one of the previous claims, wherein

the fertiliser core has an average diameter 1mm to 5mm;

the carrier powder has an average diameter no more than 100 microns; and

the thiamethoxam powder has an average diameter of no more than 100 microns.

21. The broadcast granule composition of any one of the previous claims, wherein

the amount of carrier powder plus thiamethoxam powder is about 3g/kg to about g/kg of the granule composition;

the amount of volatile material in the formulation is no more than 4% w/w of the granule composition; and

the amount of sticking agent in the formulation is about 1 g/kg to about 10 g/kg of the granule composition.

22. A method for the preparation of broadcast granules comprising thiamethoxam the process comprising

* providing a dry granule core; • agitating the core in the presence of a powder mixture to dry-coat the core with the powder mixture comprising thiamethoxam powder in admixture with a powder carrier, * blending the dry-coated core with a sticking agent to provide an adhered coating of sticking agent that overlays the powder coated core.

23. The method for the preparation of broadcast granules according to claim 22 wherein agitating the core in the presence of a powder mixture to dry-coat the core is conducted in a rotating mixing vessel selected from a drum or pan or a mixing vessel with an agitator such as a rotating screw.

24. The method for the preparation of broadcast granules according to claim 22 or 23, wherein and include an initial step of adding the core to the mixing vessel; gradually adding to the core a fine-powder mixture that comprises thiamethoxam powder and a carrier powder under agitation to form a dry blend, and slowly adding the sticker to the dry blend under further agitation to provide a coating of sticker about the dry blend.

25. The method for the preparation of broadcast granules according to any one of claims 22 to 24, wherein the sticking agent is selected from the group consisting of polybutene having and a Kinematic viscosity of at least 300 centistokes (cSt) at 400 C and is added to the dry coated core at a temperature of 400 C to 130°C.

26. The method for the preparation of broadcast granules according to any one of claims 22 to 25, wherein the powder mixture is added to the core over a period of 5 minutes to two hours and the sticker at a temperature of 400 C to 130 0C is added to the powder coated core over a period of from 5 minutes to two hours.

27. The method for the preparation of broadcast granules according to any one of claims 22 to 26, wherein the method comprises:

• agitating the core with the powder mixture for a period of at least 10 minute to dry coat granules with the composition • adding heated sticker gradually over a period of at least 10 minute; and • blending the sticker and powder coated core, preferably for at least 10 minutes.

28. A method of controlling insects in turf, the method comprising applying the granules according to any one of claims 1 to 21 to an area of turf.