WO1998034477A2

WO1998034477A2 - Encapsulated pest control pellets and/or delivery devices for pest control

Info

Publication number: WO1998034477A2
Application number: PCT/NZ1998/000013
Authority: WO
Inventors: Jeremy Hamish Kerr; Andrew George Lavrent
Original assignee: Feral I.P. Limited
Priority date: 1997-02-11
Filing date: 1998-02-10
Publication date: 1998-08-13
Also published as: AU6007298A; WO1998034477A3

Abstract

A pest killing pellet having a fragmentable core having a lethal poison content and a composite (layered) coating adapted to render the poison undetectable until too late yet preferably to assist in poison distribution upon its being breached by pressure. Related baiting procedures and apparatus is disclosed as well as preparative procedures.

Description

"ENCAPSULATED PEST CONTROL PELLETS AND/OR DELIVERY DEVICES FOR PEST CONTROL"

TECHNICAL FIELD

The present invention relates to pellets each of which is capable of delivering into the target animal a lethal dose of a poisonous or toxic substance, the presence of the poisonous or toxic substance not being discernible by the target animal until too late. The invention relates to methods and manufacturing such pellets, the pellets themselves, the use of such pellets and related bait practices and pellet delivery and/or dispensing apparatus. BACKGROUND ART

The Possum problem in New Zealand is well known. Possums tend to have what is known as bait shyness or bait aversion. Many pests throughout the world become increasingly shy of a baited poison over a period of time owing to an association of the smell and/or flavour of a poisonous substance with non fatal previous tasting. With most feral animals the primary aversion usually result through smell and taste and this is particularly the case with a toxic poison such as cyanide.

Other pests abound in New Zealand. Those which do not masticate their food (as do possums) are better targeted using pellets adapted to be swallowed into the stomach or the like of the animal. Such pellets should be capable of being swallowed without providing any indication of the presence of the poison until the delivery into the zone of activity, ie; the stomach and intestines. DISCLOSURE OF INVENTION

In its various modes therefore the present invention relates to pellets and the use of pellets including ancillary equipment and methods capable of targeting specifically one or more of several target species such as, for example, possums, rabbits, hares, stoats, ferrets, cats, birds, pigs, deer, goats, etc.

Many birds tend to grind food in a gizzard or crop using stones. Other species may not masticate fully but if the pellet is disintegratable in a stomach or the like as a result of partial mastication and/or dissolution in gastric juices its use is enhanced by the non discernability of the poison or toxic substance until a target animal is committed. The word "animal" takes an appropriate meaning so as to encompass all appropriate target species.

Accordingly an object of the present invention in one form is to provide an pellet (preferably orally masticable, swallowable and/or disintegratable internally of the target species) as well as mixes involving any such pellet, delivery methods and related ancillary means.

It is an object in some embodiments of the present invention to provide pellets and related means and methods whereby a pellet targeted to an animal is provided with more than sufficient toxic content to deliver a lethal dose to the animal once crushed in an animal's mouth or swallowed whole, yet at the same time encapsulating the smell and taste of the toxic substance until after it is too late, ie; it has been delivered into the mouth or stomach of the animal (as the case may be).

Such a pellet scenario targetable to animals which take a pellet in to their mouth and are likely to crush or swallow or disintegrate the same will be effective provided an appropriate toxic content is encapsulated in pellets for the particular targets species.

Cyanide is particularly suited for the possum since bait shyness does not appear to be associated with the proximity of dead carcasses of animals of the same species previously poisoned.

It is a further object to provide an enteric or disintegratable tablet capable of being taken into the stomach of an animal without rejection owing to the omission of an indication of the toxic content of the pellet prior to swallowing. In such forms of the present invention while it is preferable that there be a toxic dose delivered from a single pellet this need not necessarily be the case.

As used herein the term "pellet" refers to any encapulatable form tablet or the like capable of being taken into the mouth of a target pest species and being chewed or swallowed. Its size is only limited by the target species and the lethal dose of the carried poison required for such an animal.

As used herein the term "poison" includes any appropriate toxin, chemical or biological. Preferred chemical poisons particularly for the target species are cyanide (for example, potassium cyanide), 1080, Norbormide, Warfarin, brodifacoum, chlorophacinone, Vitamins D3 and K, Coumatetrayl, ANTU, Dipacinone and Bromadiolone. Biological poisons can include bacteria, viruses, or the like.

Accordingly, in a first aspect the present invention consists in a pellet capable of delivering a poison (undetected) into an animal (until too late), said pellet comprising a shaped core at least substantially free of water containing a lethal dose of a poison, toxic substance or the like (hereafter "poison") for the animal and an appropriate carrier (if any) to enable a shaping of the core prior to coating thereof, said core being such as to be crushable under the chewing action and/or to be degradable once swallowed, and at least one coating over said core that alone or together with any other coatings is a) substantially impervious to the issuance of vapours from the poison of the coated core and b)(i) is sufficiently strong as to ensure delivery undamaged into the mouth of the animal for chewing whereupon it is sufficiently brittle to enable the rapid disposition of the poison of the fragmentable core into the oral cavity upon crushing, or B)(ii) is sufficiently strong as to ensure oral delivery into the stomach of the animal whereupon it is sufficiently degradable and/or disintegratable to enable the rapid disposition of the poison. Preferably the core has a crush strength less than 1.0 Kg measured on a refractometer.

Preferably the pellet has a crush strength less than 8.0 Kg. In a first aspect the pellet is of a kind for delivery of the poison upon chewing, ie; delivery is via the oral cavity.

In other forms it is adapted to be swallowed and thereafter to disintegrate. Preferably said core includes a carrier and preferably that comprises a plurality of different substances, eg; carriers frequently used to deliver active ingredients in a tablet form.

Preferably said core has an average weight in the range 30 to 450 mg (most preferably 100 - 450mg).

Preferably said core is pressed to a size of about 3 to 10 mm (preferably 3 to 6 mm (preferably 5 to 6 mm for possums) diameter barrel with hemispherical ends (preferably weighing 40 to 150 mg - preferably 100 to 150 mg). Preferably the pellet in accordance with the present invention has a sequence of three coatings over the core. Preferably in the case of the enteric pellet the first coating is typically from 0.5 mm thick, the second coating is typically from 1.0 to 1.5 mm thick, and the outer coating up to 3 mm thick (maximum).

In the case of the masticable pellet the inner layer is typically from to 0.02 to 0.5 mm, the second layer is typically from 1.00 to 1.5 mm thick and the outer layer up to 3 mm thick.

In still a further aspect the present invention consists in a pellet capable of delivering a poison into an animal when the pellet is chewed by or disintegrated in the animal, said pellet comprising a core of a lethal dose of a poison or which includes a lethal dose of a poison and which is capable of breaking from its shape to better distribute the poison during chewing or after some other action leading to its disintegration, said core being at least substantially free of water, and a gas impermeable brittle coating about said core capable of being broken by chewing or by some other action within the animal yet, until it is chewed or is otherwise breached or eroded, prevents the issuance of any detectable amount of gases from the poison, said coating being of a sequence of layers.

In some animals the pellet is chewed and delivery into the bloodstream from the mouth is all that is required (eg; possums).

In others it may be into one or all of the mouth, threat, crop, gizzard, stomach, intestine and colon.

Preferably less than 0.01 μg of the poison issues from an unbreached pellet. Preferably said pellet is a pellet as previously defined having preferably three layers, the characteristics of which are preferably as hereinafter characterised.

In still a further aspect the invention consists in a pellet to orally deliver a poison entericly into the animal, said pellet comprising a core shaped with a poison and at least one excipient to be capable of disintegration under the action of the gastric liquids of the target animal so as to distribute the poison entericly, and a gas impermeable yet gastric liquid disintegratable coating about said core capable of preventing the issuance of any gases from the poison prior to swallowing, said coating being of a sequence of layers.

Preferably said pellet is of a kind hereinbefore and/or hereinafter described with more particularity to any aspects thereof and/or the production thereof.

In still a further aspect the present invention consists in a pellet capable of delivering a lethal dose of poison into a target animal (e.g. into the oral cavity of an animal and to be there masticated at least in part by the animal so as to deliver a 100% lethal dose and/or of delivering a 100% lethal dose of the poison elsewhere within an animal after oral ingestion and subsequent disintegration of the pellet), said pellet comprising a shaped core containing a lethal dose of a poison for the animal and an appropriate carrier (if any) to enable the shaping of a core prior to coating thereof, said core being such as to be readily crushable and a sequence of coatings over said core such that as a composite coating (composite in the sense of being a plurality of coatings) the coating cure provides a barrier to the issuance of vapours from the poison of the core prior to intake by a target animal and is sufficiently strong to ensure delivery undamaged into the mouth of the animal for chewing whereupon it is sufficiently brittle or disintegratable to enable the rapid disposition of the poison of the fragmentable core into the oral cavity once the coating(s) are breached.

Preferably said pellet includes in its core (i) a poison [preferably cyanide (for example, potassium cyanide) and (ii) at least one excipient which acts as a disintegrate and/or lubricant and which in conjunction with the poison allows the shaping of the core for coating purposes.

Preferably said excipients include at least one lubricant and at least one disintegrate.

Preferably a suitable lubricant is a suitable stearate.

Preferably a suitable disintegrate is selected from the group consisting of hydroxy propyl cellulose, hydroxy propyl methyl cellulose and povidone or polyvinylpyrrolidone.

Preferably the poison is potassium cyanide and it accounts for at least 85% w/w of the core.

Preferably the coating is a sequence of three coats, ie; a first sealing coat, a second coat which is radiation curable and an outer coat which is a flavour coat. Preferably said sealing coat comprises one or more of a coating of a cellulose material, a shellac material or an acrylic polymer.

Preferably said second coat is a radiation cured material selected from the group comprising alkyds, acrylics, epoxides, phenolics, polyesters and vinyls.

Preferably cured using a photo initiator or photo initiators. Suitable photo initiators include alpha hydroxy ketones, benzyl dimethyl ketone, benzophenones or similar reactive amines.

Preferably the outer coating which is a flavour coat is of a ground feed meal preferably the coating is applied with a cyanoacrylate. In other forms however the outer coating can instead or as well include gelatine and gums. Acacia gums have been found to be particularly advantageous.

The brittleness of the composite coating arises from the brittleness of the second layer which is capable of explosive disintegration carrying with it the breaking open of the sealing layer.

Preferably the outer layer does not substantially resist any such tendency to disintegrate.

In still a further aspect the present invention consists in a pellet capable of delivering a poison into the stomach and/or intestines of an animal, said pellet comprising a shaped core containing a poison for the animal and an appropriate carrier to enable a shaping of the core prior to the coating thereof, said core being such as to be degradable once swallowed, and a composite coating over said core that is sufficiently strong to ensure delivery into the animal whilst substantially impervious to the issuance of vapours from the poison yet which upon reaching the site of action is capable of rapid disintegration in the presence of gastric juices.

Preferably said core is of a poison selected from a cyanide (particularly potassium cyanide), 1080, Norbormide, Warfarin, brodifacoum, chlorophacinone, Vitamins D3 and K, Coumatetrayl, ANTU, Dipacinone and Bromadiolone and the appropriate carrier is an excipient or excipients preferably selected from disintegrates and lubricants. A preferred lubricant is by way of example a suitable stearate and a suitable disintegrate is one selected from one or more of hydroxy propyl cellulose, hydroxy propyl methyl cellulose and polyvinylpyrrolidone.

Preferably the composite layer is applied in three layers.

Preferably the first layer is a core stabilising coat of a cellulose material, a shellac material or an acrylate polymer so as to be hard but gastric soluble, ie; it is to disintegrate beyond the mouth. It need not be as brittle as that "coating" for oral cavity disintegration. Preferably the second coat is of a cellulose acetate phthalate (CAP), a polyurethane, an acrylic copoiymer, a sugar, or a gelatine coat or a mixture or any one or more thereof. Preferably said second coat is applied to the dry or substantially dry core after the application of said first coating and the second layer can be cured by rations but not necessarily not cured by radiation being applied through a liquid carrier whereas preferably in the case of the oral cavity deliverable forms the second coating thereof is eradicated whilst being borne in a liquid such as water, clycol or other suitable organic material or mixtures thereof to achieve the desired polymeric form.

Preferably the third coating is a flavour coating preferably including fibres, fats and flavours appropriate for the target species. Cinnamon oil as a flavour has been found particularly suitable but other well known flavours can be used, for example, aniseed. Where a ground feed meal including one or more of fibres, fats and flavours is preferably being applied preferably it is applied in the presence of a Cyanoacrylate. In other forms however gelatine and/or gums can be used instead or in addition. Acacia gums have been found to be particularly useful.

Preferably where the tablet is for gastric liquid disintegration a moving bed of the core (coated or otherwise) is provided so that hot or warm air can be used to evaporate solvents during the coating process or processes. This is unlike that desired for the oral cavity disintegratable form where preferably a liquid carrier borne pellet core with the first coating is carried in a liquid such as water, glycol, other suitable organic material or mixtures thereof where it can be appropriately radiated.

In yet a further aspect the present invention consists in a pellet or plurality thereof as previously defined (of either kind) in combination with (preferably mixed with) a substantially similar pellet insofar as appearance and/or smell is concerned which is non toxic and is a feed pellet.

In still a further aspect the present invention consists in a bait delivering device such as hereinafter described.

In yet a further aspect the present invention consists in a pellet feeder. These can be for pellet feed or for paste baked in peanut butter.

In still a further aspect the present invention consists in a method of controlling a feral pest which comprises providing at a bait station in a manner accessible to a feral pest to be controlled at least one pellet capable of delivering a poison as previously set forth and substantially similar tablets (feed pellets) insofar as appearance and/or smell are concerned which are non toxic and are capable of being eaten by mastication. Preferably said bait station is one as hereinafter described. Preferably there is at least one feed pellet or a feed paste for every toxic pellet. In a most preferred form of the present invention about five feed pellets or an equivalent quantity of a non toxic feed paste for every toxic pellet.

The present invention also consists in a bait station that has been baited by the use of masticatable toxic pellets and feed pellets.

In yet a further aspect the present invention consists in a method of controlling possums which comprises the use of pellets in accordance with the present invention, preferably in a bait station in accordance with the present invention and the placement in said or a bait station of a plurality of pellets in accordance with the present invention, the bait station being left (and preferably fixed) at a suitable locus of activity of the possums or possum to be controlled.

In yet a further aspect the present invention consists in a method of forming a pellet which contains an active ingredient, said method comprising forming as a shaped core the active ingredient with optional carrier materials to a shape, protecting the shape whether by a preliminary coating or careful handling or a mixture of both, applying to the core (coated or otherwise) a photo initializable composition capable of curing to a brittle and substantially vapour impervious coating (with respect to vapours being issued by the active ingredient) and photo initiating the polymerisation of that coating composition while the composition covered core is in water and/or another suitable liquid, and thereafter harvesting the pellet.

Preferably the method includes an additional step of applying a cover coating which preferably includes baiting compounds, ie; luring and/or enticement substances.

Preferably said core preparation involves the use of pressure and substances capable of being formed to a soft tablet or pellet form in addition to the active ingredient. Preferably the active ingredient is a poison.

Preferably the poison is KCN or another suitable delivery source for cyanide. Preferably therefore the photo initiated barrier coding is substantially impervious to hydrogen cyanide.

In a further aspect the present invention consists in apparatus for providing a pellet having a core of a pellet encased in a polymerised material comprising means to substantially serially provide a discharge of core pellets each coated (optionally after a precoating) with a polymerisable liquid composition capable of having its cured photo initiated, means to

(i) receive said composition coated cores into a liquid compatible with said composition and which liquid is transparent to light of the photo initiating wavelength(s) (ii) transport said coated cores through a zone where said liquid and said coated cores are exposed to cure initiating light, and

(iii) discharge the cores with their cure coating, means to collect the discharged pellets and means to provide said cure initiating light. Preferably said means to receive transport and discharge the coated cores allows the coated cores to move primarily under the influence of gravity.

Preferably said means to receive transport and discharge is largely in the form of a vertically extending duct having over the zone where said liquid and said coated cores are exposed to cure initiating light formed of a light transparent material, eg; quartz. Preferably means is provided to recirculate at least some of the liquid. Preferably a refrigeration unit is provided to chill the recirculating liquid. Preferably said chilling is to a temperature range of from about 5 °C to about 20 °C (e.g. about 5°C to about 10 °C). Preferably said cores are cores as previously set forth and preferably said coating is that coating previously set forth.

Preferably said means to discharge the cores are each coated with a polymerisable liquid composition capable of having its set photo initiated is a bath of such a polymerisable liquid composition including means capable of lifting the coated cores so that they fall into said liquid of said means to receive transport and discharge.

Preferably said polymerisable liquid has a viscosity range of from 300 to 900 Cpi at 18°C to l9°C.

Preferably said liquid is water.

Preferably the apparatus is substantially as hereinafter described.

In a further aspect the present invention consists in a method of providing a pellet having a core encased in a polymerised material (preferably a core as previously set forth and preferably a vapour proof brittle coating as previously set forth), said method comprising serially providing a discharge of cores of pellets each coated (optionally after a precoating) with a polymerisable liquid composition capable of having its cure photo initiated, receiving said composition coated cores into a liquid compatible with said composition, which liquid is transparent to light of the photo initiating wavelength(s), transporting said coated cores through a zone where said liquid and said coated cores are exposed to cure initiating light sufficient to ensure a rapid cure, and thereafter discharging the cores from said liquid, the coating having cured.

Preferably the curing occurs in less than 10 seconds.

Preferably the transportation in said liquid is longer than the period of any such set.

Preferably said liquid is water.

Preferably water is chilled to from about 5 °C to about 20 °C preferably during recycle.

In a further aspect the present invention consists in apparatus for hardening a photo initiated coating on a core (irrespective of whether or not the core is pre-coated,) (such as for a pellet as previously set forth), said apparatus comprising means to confine a UV light transparent liquid compatible with the core and the coating, means to generate UV light into the liquid and onto any photo initializable coating composition therein, and means whereby, by movement of the liquid or otherwise (eg; gravity), coated cores (the coating being of a photo initializable composition) can be serially or substantially serially passed through the UV light while confined within said liquid.

Preferably said UV light is applied at 300 W per square inch at 12-14 mm focus.

Preferably said liquid is a column of a liquid (such as water) confined in a glass tube of any cross-sectional shape (or other UV transparent material), there being an inlet for the cores and coating composition at or adjacent the top and an outlet or collection zone therefor at or adjacent to the bottom or leading from the bottom.

In a further aspect the invention is a pellet feeder formed from an assembly or assemblage of components to define a main body which defines a reservoir for pellets and a dispensing zone from which an animal can access pellets that have moved under gravity from said hopper to said zone, means to close the hopper after the filling thereof, means to cover the dispensing zone, and means which enables the device as a whole to fix by penetrative means into a support structure.

Preferably said last two means are one and the same means, the same component in one mode being capable of acting as a said closure and, in another mode, when affixed differently, of acting as the penetrative member.

Preferably a pivotal cover in addition is provided for said dispensing zone.

In some forms of the present invention, the devices are adapted to dispense a feed paste in conjunction with the pellets. Preferably the feeding is of the paste (eg; based on peanut butter) and the pellets together.

In other forms of the present invention a separate feed from its own reservoir of the paste to that of the pellets occurs.

In yet a further aspect the present invention consists in, in combination a feed paste (eg; based on peanut butter) and at least a plurality of pellets (masticatable or enteric) in accordance with the present invention.

Preferably all of said pellets are either of the masticable form or the enteric form. In yet a further aspect the present invention consists in a use of a pellet feeder device as previously set forth and/or substantially as hereinafter described preferably with reference to any one or more of the accompanying drawings.

The pellets of the present invention in preferred forms present toxins in pellets to feral animals in such a way they can not detect the toxic inclusion when mixed with now toxic feeds palatable and acceptable to the animal. The encapsulation process prevents any detection of odour or taste, with gas emission less than 0.001 μg from any toxic substance within the core of the pellet.

The encapsulated toxic pellet is prepared in such a way that it can deliver a 100% lethal dose and be presented to resemble other non toxic feeds within a bait.

The UV curing of a substantially 100% polymerisable liquid provides a dense chemical matrix bonding to prevent such emissions whilst being hard, brittle, odourless, tasteless and have the ability to slowly dissolve in soils if left exposed in the environment for more than 2-6 weeks. BRIEF DESCRIPTION OF DRAWINGS:

Preferred forms of the present invention will now be described with reference to the accompanying drawings in which;

Figure 1 shows a preferred pellet encased capable of photo initialising the set of the polymerisable material while in a liquid such as water,

Figures 2A to 2B are views of a bait station for pellets of two types (feed plus poisoned),

Figures 3 A and 3B are views of a bait station for a feed paste and pellets.

Figure 4 is a view of one form of pellet in accordance with the present invention being barrel shaped and with arcuate ends or in another preferred form a hemispherical end, and

Figure 5 is a cross sectional view of the pellet of Figure 3 showing the multiple coatings thereof.

In the accompanying drawings the core 1 includes a thin pre coating 2 the brittle photo initializable coating 3 and a lure or bait containing coating 4. ORAL CAVITY DISINTEGRABLE PELLETS FOR POSSUMS:

The pellet technology and its use consist of four parts:- a) core b) three coats - 1st - a stabilising coat,

- 2nd - an encapsulating coat, and

- 3rd - a functional coat (e.g. a bait). c) Bait station delivery device to target and lure animals to the pallet. d) The preferably identical or similar appearing and swelling feed pellets to encourage at the bait station faster and more confident mastication.

A) THE PELLET CORE

Average weight 30 to 600 mg (100 to 450

Pressed size

mm. dia. barrel shaped with 180° round ends. Average Contents: (by weight)

KCN 95%

Avicel 3.5%

Talc and/or 0.5%

Magnesium Stearate 1%

The chemicals are stored, dried and blended at approximately 25°c with relative humidity of 10 - 20% maximum.

The mixture is then processed into pellets using tablet press equipment. The pellet is pressed to the lowest limit of compression before it is given the first coat.

Keys to Pellet Core Construction: 1) The core should be dry. 2) The core for oral cavity disintegration preferably should contain enough of the toxic substances to kill the target species. Generally twice times the L.D. is required in the pellet, allowing for the toxic material that falls from the mouth or remains on the coating as the pellet disintegrates in the mount.

Bl. THE FIRST COAT: (Stabilising or Bracing Coat)

A solution of ETHYL CELLULOSE (eg ΕTHYCELL STANDARD 7 Dow) is mixed 10 - 15% by weight with Acetone/Alcohol mixture to form a spray coat solution. This is applied to the pellets very lightly preferably to a maximum thickness of 0.5 mm. Features:

- braces the brittle soft pellet core preventing any disintegration or chipping when handling. The solution is inert and has no reaction with the core. It is also tasteless and odourless.

- protects the core from contamination from the second coat before it cures.

- the ethylcell coat is thin, brittle under pressure and does not bind or stick to the core.

- the solution is sprayed onto the pellets in a tablet coating bowl.

B2. SECOND COAT: (Total encapsulating coat)

The trade name of this product before modification is 'FIP 02' produced by Whitehall and Innovative Groups. It is a mixture of urethanes and Epoxides. It is 100% solids and is cured with 'Photo initiators', e.g. radiation curing. To this is added: - approximately 3.5% Acrylate Copoiymer w/w, and/or 3 - 5% of silica dioxide (eg; SYLOID 72) by weight (thickens with the SYLOID also acting as a surface roughener) This solution is mixed 2 hours before application to prevent any separation. This product is kept at room temperature (i.e. 18°C to 19°C).

The acrylate copoiymer is added to increase the viscosity and provide water resistant properties to the solution. The SYLOID is added to give the cured surface a rough texture for the third coat to attach to. The pellets with the first coat on are then briefly immersed in this second coat solution then dropped vertically through water for 4 - 6 seconds in a 360° defused tunnel of U.V. radiation of 200-3 OOw/sq' at 5 - 7cm focus from light source. The light source or U.V. should provide absorption peaks of between 220-400nm. The water the pellet is falling through should be kept in the 5 - 20°C range to prevent thermal shock causing cracks in the coating as it cures. The total time to cure is 4 - 6 seconds. Features: (To curing the encasing coat solution) the solution should cure quickly, totally encasing the pellet, the cured coat will prevent any gas-odour emission from the core: be able to withstand temperature changes in the natural environment between -20°C to +45°C without cracking or degrading immediately. It is best that the curing is quick (eg; 4 to 6 seconds) and the heat from the exothermic reaction is dispersed as quickly as possible away from the pellet core, the finished coat should be hard but brittle, curing to a thickness of approximately 1.0 mm. When suitable mouth-jaw pressure is applied to the = coating it must crack and disintegrate with the core contents around the animal's mouth. the cured coat should be odourless and tasteless. the pellets fall through the water is to slow down the rate of fall increasing the time available to get a full cure in approximately 4 - 6 seconds. The free falling allows the coating solution to fully encase the pellet. See Figure 1 which shows a preferred pellet encased where:

1) container of coating solution and pellets. The pellets enter the fusion tower from the opening at the top.

2) alloy diffuser 360°C. -

3) refrigeration unit providing filtered, chilled water 5° - 20° range, circulating up slowly through the glass tube.

4) light source with cooling blower focussed at 5 - 7 cm from the centre of the glass tube.

5) exhaust for air flow from the heat generated by the light air entering via the lights blower. 6) fusion tower holding the water - the pellets fall from the top.

7) exit of encased pellets.

Dimension:

Length of tower lm tube size 40 mm x 200 mm.

Distance of UV focus from the bulb in the tube 5 - 7 cm.

UV 200-400 w/sq in at 220 - 400 NM

Pellet fall 4 - 6 seconds

B.3 THIRD COAT: (Functional Coating)

This coat is designed to lure and entice the animal to first smell, then lick, then transfer the pellet to its mouth, chewing it and releasing the core contents.

The feed bases used will vary with each species depending on the natural preferences. Possum pre-feed grain - sweet based feeds, ie. sugars and meal based grain feeds and some fats. These are mixed together and coated to the second coat with adhesives or similar binding coats preventing the coating from being removed easily, thus enticing the animal to chew its way to the flavour. Features: the feed base should bond firmly to the pellet. the feed base should have flavours and odours consistent with those used in the pellet core and other pre-feed bases used to lure the animal independent of the toxic pellets. the feed base texture for possums is a firm hard feed not easily swallowed without chewing. unless regulations require, the colour is left natural.

THE SWALLOWABLE TABLET FOR FERAL ANIMALS

A THE PELLET CORE: Average weight 50 to 600 mg (100 to 450 mg for several of the species)

Pressed size rats x 2 mm rabbits = 4.2 mm possums ^ 4.8 mm stoats ~ 4.2 mm cats s: 4.2 mm goats Si 10 mm deer ~ 10 mm wallabies ~ 10 mm pigs ~ 10 mm

mm. dia. barrel shaped with 180° round ends. Average Contents: (by weight)

KCN 95%

Disintegrant 3.5%

Talc and/or 0.5%

Magnesium Stearate 1%

Keys to Pellet Core Construction:

1) The core should be dry.

2) The core for oral cavity disintegration preferably should contain enough of the toxic substances to kill the target species. Generally twice times the L.D. is required in the pellet, allowing for the toxic material that falls from the mouth or remains on the coating as the pellet disintegrates in the mount.

Bl. THE FIRST COAT: (Stabilising Coat)

A solution of a pH dependent coating material (eg; derived from Hydroxypropyl Methyl Cellulose Phthalate or Polyvinylacetate Phthalate (P.V.P.A) [10 - 15% by weight] and solvent [such as Alcohol/ Acetone/Methylene Choride etc.] was applied to a maximum thickness of about 0.50 mm. Features:

- protects the core from contamination from the second coat before it cures.

- the coat is thin, brittle under pressure and does not bind or stick to the core.

- this is an enteric coat.

- the solution is sprayable onto the pellets in a tablet coating bowl.

B2. SECOND COAT: (encapsulation)

The trade name of this product before modification is 'FIP 06' produced by us (Innovative/Feral I.P.). It is in a mixture of Resins, Plasticisers and Carriers. It is 100% solids and can be cured in two ways:

A) radiation used with photo initiators.

B) modified immersion tube coating pan process - whereby the tablet coating process ensures there is the application of a coating composition by spray or atomizing into a rotating coating pan with the concurrent use of heated air and/or radiation to facilitate evaporation of the carrier solvent and/or curing of the photo active coating material.

To this is added:- approximately 3.5% Acrylate Copoiymer w/w, and/or 3 - 5% of silica dioxide (eg; SYLOID 72) by weight (thickens with the SYLOID also acting as a surface roughener) This solution is mixed 2 hours before application to prevent any separation. This product is kept at room temperature.

The acrylate copoiymer is added to increase the viscosity and provide water resistant properties to the solution. The SYLOID is added to give the cured surface a rough texture for the third coat to attach to.

The pellets with the first coat on are then briefly immersed in this second coat solution then dropped vertically through water for 4 - 6 seconds in a 360° defused tunnel of U.V. radiation of 200-300 watts/square inch at 5 - 7cm focus from light source. The light source or U.V. should provide absorption peaks of between 220-400nm. The water the pellet is falling through should be kept in the 5 - 10°C range to prevent thermal shock causing cracks in the coating as it cures. The total time to cure is 4 - 6 seconds. Features: (To curing the encasing coat solution)

- the solution should cure quickly, totally encasing the pellet.

- the cured coat will prevent any gas-odour emission from the core: be able to withstand temperature changes in the natural environment between -20°C to

+45°C without cracking or degrading. It is best that the curing is quick (eg; 4 to 6 seconds) and the heat from the exothermic reaction is dispersed as quickly as possible away from the pellet core.

- the finished coat should be hard but brittle, curing to a thickness of approximately 0.3mm. When suitable mouth-jaw pressure is applied to the coating it must crack and disintegrate with the core contents around the animal's mouth.

- the cured coat should be odourless and tasteless.

- the pellets fall through the water is to slow down the rate of fall increasing the time available to get a full cure in approximately 4 - 6 seconds. The free falling allows the coating solution to fully encase the pellet.

See Figure 1 which shows a preferred pellet encased where:

2) alloy diffuser 360°C. -

3) refrigeration unit providing filtered, chilled water 5° - 10° range, circulating up slowly through the glass tube.

5) exhaust for air flow from the heat generated by the light air entering via the lights blower.

6) fusion tower holding the water - the pellets fall from the top.

7) exit of encased pellets . Dimension:

Length of tower lm tube size 40 mm x 200 mm.

Distance of UV focus from the bulb in the tube 5 - 7 cm.

UV 200-400 w/sq in at 220 - 400 NM

Pellet fall 4 - 6 seconds

B.3 THIRD COAT: (Functional Coating)

The feed bases used will vary with each species depending on the natural preferences. Possum pre-feed grain - sweet based feeds, ie. sugars and meal based grain feeds. These are mixed together and coated to the second coat with adhesives or similar binding coats preventing the coating from being removed easily, thus enticing the animal to chew its way to the flavour. Features:

- the feed base should bond firmly to the pellet.

- the feed base should have flavours and odours consistent with those used in the pellet core and other pre-feed bases used to lure the animal independent of the toxic pellets.

- mode of action; enteric, where the active is released within the intestine or stomach.

- unless regulations require, the colour is left natural.

In Figures 2 A and 2B there are two views of a pellet feeder for use with the pellets of the present invention. Such a device can be used firstly to feed animals to be targeted with the poisons and then subsequently to be loaded with the poisoned pellets of the present invention. In the case of possums preferably the masticable form thereof.

As can be seen there is a hopper region 1 having an outlet 2 for the pellets this outlet is coverable by a cover 3 which preferably can be uplifted about a pivot by the animal being targeted. During carriage however preferably the tree or post engaging penetrative member 4 is disengaged from the condition shown in Figures 2A and 2B and is instead engaged with its spike region 5 inside the receiving opening 6 and with its other penetrative members 6 about the skirt 7 of the outlet 2.

By such means there is less likelihood for already loaded pellets within the hopper to be discharged during such carriage.

The means by which the member 4 is disengaged from its carrying condition is simply by opening of the cover 3 and the pulling of the same free and then the engagement thereof back into the device as shown, preferably using some spline or some other like fitment if necessary a screw or the like means 8 can be provided to ensure the integrity of the assembly.

The bait station variant shown in Figures 3A and Figure 3B is similar to that of Figures 2A and 2B but is adapted to allow the dispensing of a feed paste prior to or with the pellets. In this respect the device would be loaded so as not to interfere with the hopper feed of the pellets to the outlet thereof and openings allow access to such a feed as well as to the pellets in the same way previously described in relation to Figures 2 A and 2B.

The device preferably also is closeable and preferably has the disengagable penetrative member also.

Other variations are bound.

THE USE OF THE FIGURE 2A AND 2B DEVICES

The possum noses himself as close as possible to the bait through the exposed opening with enough forward force to lift the lid which gets lighter in weight as it moves up.

The possum inspects the bait, removes a pellet then retires back. The lid closes with its own weight.

It is most preferred the device is attached (eg; by screw hole (12)) between 8 - 12cm off level ground.

Rats and birds have no leverage on the lid at this height.

The Bait Station Unit is designed to present the pellets to the possum in its environment in such a way that it gives maximum exposure to the possum without any exposure to other species, exposure to other species, especially rats. Features: - Only possums gain access.

- Keeps the pellet and feed pellets protected against the weather.

- Prevents non target species i.e. birds, etc. accidentally accessing the unit.

- Light and easy to handle for the operator.

- Can be used for the pre-feed function.

- Is safe and effective way of handling and storing the pellets.

- Easy to locate in the environment.

- Can have the attracting lure-odours, incorporated into the unit.

Claims

CLAIMS:

1. A pellet capable of delivering a poison (undetected) into a target species animal (until too late), said pellet comprising

(II) a shaped fragmentable core at least substantially free of water containing (i) a lethal dose of a poison, toxic substance or the like (herein "poison") for the target species animal and (ii) an appropriate carrier (if any) to enable a shaping of the core prior to coating thereof, and

(II) at least one coating over said core that alone or together with any other coatings is a) substantially impervious to the issuance of vapours from the poison of the coated core and b)(i) is sufficiently strong as to ensure delivery undamaged into the mouth of the target species animal for chewing whereupon it is sufficiently brittle to enable the rapid disposition of the poison of the fragmentable core into the oral cavity upon crushing, or

B)(ii) is sufficiently strong as to ensure oral delivery into the target species animal whereupon it is sufficiently degradable and/or disintegratable once swallowed to enable the rapid disposition of the poison of the fragmentable core.

2. A pellet of claim 1 to be masticated by a target species animal.

3. A pellet of claim 1 to be swallowed by a target species animal without any substantial chewing prior to swallowing.

4. A pellet of any one of the preceding claims wherein the core has a crush strength less than 1.0 Kg measured on a refractometer.

5. A pellet of any one of the preceding claims wherein the pellet has a crush strength less than 8.0 Kg measured on a refractometer.

6. A pellet of any one of the preceding claims wherein said core is pressed to a maximum size of about 2 to about 10 mm.

7. A pellet of any one of the preceding claims wherein said core has an average weight in the range 30 to 600 mg.

8. A pellet of any one of the preceding claims wherein said core has an average weight in the range 100 - 450 mg.

9. A pellet of any one of the preceding claims wherein said at least one coating is a sequence of three coatings over the core.

10. A pellet of claim 9 wherein, in the case of the swallowable pellet, the first coating is typically up to 0.5 mm thick, the second coating is typically from 1.0 to 1.5 mm thick, and the outer coating up to 3 mm thick.

11. A pellet of claim 10 wherein, in the case of the masticable pellet, the inner layer is typically from to 0.02 to 0.5 mm, the second layer is typically from 1.0 to 1.5 mm thick and the outer layer up to 3 mm thick.

12. A pellet of any one of the preceding claims wherein the poison is selected from the group comprising a cyanide, 1080, Norbormide, Warfarin, brodifacoum, chlorophacinone, Vitamins D3 and K, Coumatetrayl, ANTU, Dipacinone and Bromadiolone.

13. A pellet of claim 14 wherein the poison is potassium cyanide.

14. A pellet of any one of the preceding claims wherein less than 0.01 μg of the poison issues from an unbreached pellet.

15. A pellet of any one of the preceding claims wherein, in its core there is (i) a poison and (ii) at least one excipient which acts as a disintegrant and/or lubricant and which in conjunction with the poison allows the shaping of the core for coating purposes.

16. A pellet of claim 17 wherein said excipients include at least one lubricant and at least one disintegrant.

17. A pellet of claim 17 or 18 wherein said lubricant is a suitable stearate.

18. A pellet of any one of claims 17 to 19 wherein disintegrant is selected from the group consisting of hydroxy propyl cellulose, hydroxy propyl methyl cellulose and povidone or polyvinylpyrrolidone.

19. A pellet of any one of the preceding claims wherein the poison is potassium cyanide and it accounts for at least 85% w/w of the core.

20. A pellet of any one of the preceding claims wherein the coating is a sequence of three coats, a first core stabilising coat, a second coat which is radiation curable and an outer coat which is a flavour coat.

21. A pellet of claim 22 wherein said sealing coat comprises one or more of a coating selected from any of a cellulose material, a shellac material and an acrylic polymer.

22. A pellet of claim 22 or 23 wherein said second coat is a radiation cured material selected from the group comprising alkyds, acrylics, epoxides, phenolics, polyesters and vinyls.

23. A pellet of claim 20, 21 or 22 wherein the second coat has been cured using a photo initiator or photo initiators.

24. A pellet of claim 23 wherein the photo initiator(s) is (are) selected from alpha hydroxy ketones, benzyl dimethyl ketone, benzophenones or similar reactive amines.

25. A pellet of any one of claims 20 to 26 wherein the outer coating which is a flavour coat is of a ground feed meal or pollards.

26. A pellet of any one of claims 20 to 27 wherein the outer coating is applied with a cyanoacrylate.

27. A pellet of any one of the preceding claims wherein the outer coating includes gelatine and/or a gum or gums.

28. A pellet of claim 29 wherein the outer coating includes an Acacia gums.

29. A pellet of any one of claims 20 to 28 wherein the brittleness of the coating arises from the brittleness of the second layer which is capable of explosive disintegration carrying with it the breaking open of the core stabilising layer.

30. A pellet as claimed in any one of the preceding claims wherein at least one coating of the pellet has been cured using radiation applied to the uncured coating in a liquid environment.

31. A pellet as claimed in claim 30 wherein the liquid environment is of water.

32. In combination at least one pellet as claimed in any one of the preceding claims and one or more of -

1. a liquid or paste like feed baiting composition,

2. non toxic feed pellets of a similar appearance and size to the toxic pellets as claimed in any one of claims 1 to 30, and

3. a bait station as claimed in any one of claims 51 to 53.

33. A method of forming a pellet as claimed in any one of claims 1 to 31 when performed by a procedure which first compacts the core and during the coating or at least one coating procedure cures the uncured exposed coating using radiation whilst it is in a liquid environment.

34. A method as claimed in claim 33 wherein said liquid environment is water.

35. A method of controlling a feral pest which comprises providing at a bait station in a manner accessible to a feral pest to be controlled at least one pellet as claimed in any one of claims 1 to 31 simultaneously with or subsequent to the similar provision of substantially similar tablets (feed pellets) insofar as appearance and/or smell are concerned, which substantially similar tablets are non toxic and are capable of being eaten by mastication.

36. A method of controlling possums which comprises the use of pellets in any one of claims 1 to 31 preferably in a bait station as claimed in any one of claims 51 to 53 and the placement in said bait station of a plurality of pellets as claimed in any one of claims 1 to 3 (optionally after or with baiting) the bait station being left (and preferably fixed) at a suitable locus of activity of the possums or possum to be controlled.

37. A method of forming a pellet which contains an active ingredient, said method comprising; forming as a shaped core the active ingredient with optional carrier materials to a shape, protecting the shape whether by a preliminary coating or careful handling or a mixture of both, applying to the core (coated or otherwise) a photo initializable composition capable of curing to a brittle and substantially vapour impervious coating (with respect to vapours being issued by the active ingredient) and photo initiating the polymerisation of that coating composition while the composition covered core is in water and/or another suitable liquid, and thereafter harvesting the pellet, the resultant pellet being a pellet capable of delivering a poison (undetected) into a target species animal (until too late), said pellet comprising

(I) a shaped fragmentable core at least substantially free of water containing (i) a lethal dose of a poison, toxic substance or the like (herein "poison") for the target species animal and (ii) an appropriate carrier (if any) to enable a shaping of the core prior to coating thereof, and

38. A method of forming a pellet which contains cyanide, said method comprising ; forming as a shaped core the cyanide with optional carrier materials to a shape, coating the shape with first coating substantially impervious to cyanide emissions, applying to the core (coated or otherwise) a photo initializable composition capable of curing to a brittle coating and polymerisation of that coating composition with radiation, and thereafter harvesting the pellet, the resultant pellet being a pellet capable of delivering a poison (undetected) into a target species animal (until too late), said pellet comprising

(I) a shaped fragmentable core at least substantially free of water containing (i) a lethal dose of a cyanide for the target species animal and (ii) an appropriate carrier (if any) to enable a shaping of the core prior to coating thereof, and

(II) a composite coating over said core being a) substantially impervious to the issuance of cyanide vapours to a target animal and b)(i) is sufficiently strong as to ensure delivery undamaged into the mouth of the target species animal for chewing whereupon the photo polymerised coating is sufficiently brittle to enable the rapid disposition of the cyanide of the fragmentable core and rupturable first into the oral cavity upon crushing, or

B)(ii) is sufficiently strong as to ensure oral delivery into the target species animal whereupon it is sufficiently degradable and or disintegratable once swallowed to enable the rapid disposition of the cyanide of the fragmentable core.

39. A method of forming a pellet which contains a toxic ingredient, said method comprising ; forming as a shaped core the active ingredient with optional carrier materials to a shape, protecting the shape whether by a preliminary coating or careful handling or a mixture of both, applying to the core (coated or otherwise) a photo initializable composition capable of curing to a brittle and substantially vapour impervious coating (with respect to vapours being issued by the active ingredient) and photo initiating the polymerisation of that coating composition while the composition covered core is in water and/or another suitable liquid, and thereafter harvesting the pellet, the resultant pellet being a pellet capable of delivering the toxic ingredient (undetected) into a target species animal (until too late), said pellet comprising

(I) a shaped fragmentable core at least substantially free of water containing (i) a lethal dose of the toxic ingredient for the target species animal and (ii) an appropriate carrier (if any) to enable a shaping of the core prior to coating thereof, and

(II) at least one coating over said core that alone or together with any other coatings is a) substantially impervious to the issuance of vapours from the toxic ingredient of the coated core and b)(i) is sufficiently strong as to ensure delivery undamaged into the mouth of the target species animal for chewing whereupon it is sufficiently brittle to enable the rapid disposition of the toxic ingredient of the fragmentable core into the oral cavity upon crushing, or

40. Apparatus for providing a pellet having a core of a pellet encased in a polymerised material comprising; means to substantially serially provide a discharge of core pellets each coated (optionally after a precoating) with a polymerisable liquid composition capable of having its cure photo initiated, means to

(i) receive said composition coated cores into a liquid compatible with said composition and which liquid is transparent to light of the photo initiating wavelength(s)

(ii) transport said coated cores through a zone where said liquid and said coated cores are exposed to cure initiating radiation, and

(iii) discharge the cores with their cured coating, means to collect the discharged pellets, and means to provide said cure initiating light.

41. Apparatus of claim 40 wherein said means to receive, transport and discharge the coated cores allows the coated cores to move primarily under the influence of gravity.

42. Apparatus of claim 40 or 41 wherein said means to receive transport and discharge is largely in the form of a vertically extending duct which at least in part over the zone where said liquid and said coated cores are exposed to cure initiating light is formed of a UV light transparent material, eg; quartz.

43. Apparatus of any one of claims 40 to 42 wherein means is provided to recirculate at least some of the liquid.

44. Apparatus of any one of claims 40 to 43 adapted to provide said liquid in a temperature range of from about 5°C to about 20 °C.

45. A method of providing a pellet of any one of claims 1 to 31 , said method comprising serially providing a discharge of cores of such pellets each coated (optionally after a pre-coating) with a polymerisable liquid composition capable of having its cure at least photo initiated, receiving said composition coated cores into a liquid compatible with said composition, which liquid is transparent to light of the photo initiating wavelength(s), transporting said coated cores through a zone where said liquid and said coated cores are exposed to cure initiating radiation sufficient to ensure a rapid cure, and thereafter discharging the coated cores from said liquid, the coating having cured.

46. A method of claim 45 wherein the curing occurs in less than 10 seconds.

47. A method of claim 45 or 46 wherein said polymerisable liquid composition has a viscosity range of from 300 to 900 Cpi at 18°C to 19°C.

48. A method of claim 44, 45 or 46 wherein the compatible liquid is water at from about 5°C to about 20°C.

49. Apparatus for hardening a photo initiated coating on a core (irrespective of whether or not the core is pre-coated), said apparatus comprising means to confine a UV light transparent liquid compatible with the core and the coating, means to generate UV light into the liquid and onto any photo initializable coating composition therein, and means whereby, by movement of the liquid or otherwise (eg; gravity), coated cores (the coating being of a photo initializable composition) can be serially or substantially serially passed through the UV light whilst confined within said liquid.

50. Apparatus of claim 49 wherein said UV light is applied at 300 W per square inch at 12-14 mm focus.

51. Baiting station apparatus comprising or having an assembly or assemblage of components to define a main body which defines a reservoir for pellets and a dispensing zone from which an animal can access pellets that have moved under gravity from said reservoir to said zone, means to close the reservoir after the filling thereof, means to cover the dispensing zone, and means which enables the device as a whole to be fixed by penetrative means into a support structure.

52. Apparatus of claim 51 wherein said last two means are one and the same means, the same component in one mode being capable of acting as a said closure and, in another mode, when affixed differently, of acting as the penetrative member.

53. Apparatus of claim 50 or 52 wherein a target animal liftable pivotal cover is provided for said dispensing zone.