NZ522468A - Use of long-life polymer baits as lures for kill traps - Google Patents

Abstract

A long life bait, attractive to mammalian vertebrate pests, which includes: a) lure ingredients, such as for example vanilla flavouring, bacon, bacon flavouring, fish oil and garlic; b) palatable ingredients, includes for example cereal based ingredients such as syrup, maize, sugar, linseed oil. Additionally, it may include protein ingredients such as fish and chicken meal for example. The bait is characterized in that it also includes at least one polymer compound selected from a plastic, an elastomer, a resin, or a combination of the above. The polymer may include ethyl vinyl acetate.

Description

New Zealand Paient Spedficaiion for Paient Number 522468 1 PATENTS FORM NO. 5 PATENTS ACT 1953 COMPLETE SPECIFICATION After Provisional No: 522468 Dated: 7 November 2002 James & Wells Ref: 42288/29 InteHectual Property Office of NZ JUN 2003 received Bait Composition We, Pest-Tech Ltd., a New Zealand company, of Level 10, 137 Armagh Street, Christchurch, New Zealand, hereby declare the invention for which we pray that a patent may be granted to us, and the method by which it is to be performed to be particularly described in and by the following statement: 2 BAIT COMPOSITION TECHNICAL FIELD The invention is related to bait compositions. More specifically, the invention 5 relates to bait compositions that have an increased stability (retain their attractiveness) to the pest over a time of weeks.

BACKGROUND ART A variety of baits have been considered in the prior art for attracting animals, 10 particularly for trap applications. Most baits are simple, such as cereal pellets, carrots, apple, and pastes. However these baits are not durable and have mixed effectiveness. In particular, because these fresh foods are short lived, they only remain attractive to a pest for a few days and are only useful for short-term applications e.g. traps checked daily.

Non-toxic techniques for controlling vertebrate pests are mainly reliant on use of live-capture, leg-hold, or kill traps, using fresh foods (e.g., fruit, meat, cheese) to lure the pest into the trap.

There is a legal requirement to inspect live-capture and leg-hold traps daily (Animal Welfare Act 1999), and consequently fresh foods can be replaced during 20 each visit to traps. However, traps that kill vertebrate pests humanely (i.e., render captured animals irrecoverably unconscious within 3 min) can be checked infrequently (e.g., every 1-8 weeks) provided the lure in the trap remains attractive to the target species for several weeks. 3 The problem then becomes how to develop a bait that remains attractive to the pest over long periods of time (1-8 weeks). Various environmental factors influence stability (attractiveness) of the bait.

One method of extending the life of bait is that described in WO 00/02447 which 5 uses bait made of carrageenan and/or sodium alginate as a gelling agent in combination with a pesticide. The pesticide is incorporated within the gel matrix. A main aim of this bait is to have an improved water resistance and also to release the pesticide in a control manner.

NZ Patent No. 212030 also describes a gel based slow release material.

NZ Patent No. 122692 also notes the problem of water resistance and attempts to resolve this problem by use of dehydrating agents including anhydrous salts, salts of polybasic acids and oxides such as silica gel.

NZ Patent No. 126351 attempts to address the problem of stability by use of polyalkylene glycol.

NZ Patent No. 136485 attempts to address the problem of stability by use of orthophosphoric acid ester, a dispersant or emulsifier, and silicic acid.

NZ Patent No. 234226 uses neem seeds to increase stability of a pesticidal agent mixed with the seed.

NZ Patent No. 281802 uses lignan and sugar alcohol to increase the stability of the 20 mixture against degradation from UV light.

The above methods address some of the factors associated with stability of attractiveness to the pest. Most however use materials that in themselves are expensive.

It is an object of the present invention to provide an alternative bait composition that is stable for longer durations or at least to provide the public with a useful choice.

All references, including any patents or patent applications cited in this specification are hereby incorporated by reference. No admission is made that any reference constitutes prior art. The discussion of the references states what their authors assert, and the applicants reserve the right to challenge the accuracy and pertinency of the cited documents. It will be clearly understood that, although a number of prior art publications are referred to herein, this reference does not constitute an admission that any of these documents form part of the common general knowledge in the art, in New Zealand or in any other country.

It is acknowledged that the term 'comprise' may, under varying jurisdictions, be attributed with either an exclusive or an inclusive meaning. For the purpose of this specification, and unless otherwise noted, the term 'comprise' shall have an inclusive meaning - i.e. that it will be taken to mean an inclusion of not only the listed components it directly references, but also other non-specified components or elements. This rationale will also be used when the term 'comprised' or 'comprising' is used in relation to one or more steps in a method or process.

Further aspects and advantages of the present invention will become apparent from the ensuing description which is given by way of example only.

DISCLOSURE OF INVENTION According to one aspect of the present invention there is provided a long life bait, attractive to mammalian vertebrate pests, which includes: lure ingredients; Intellectual Property Office of KZ 0 9 JUL 2003 palatable ingredients; and is characterised in that the bait also includes at least one polymer compound selected from the group consisting of: a plastic; an elastomer; a resin; and combinations thereof.

According to a further aspect of the present invention there is provided a long life bait, attractive to vertebrate pests, substantially as described above wherein the at least one polymer compound is capable of binding the bait ingredients together.

According to a further aspect of the present invention there is provided a long life bait, attractive to vertebrate pests, substantially as described above wherein the at least one polymer compound also increases the water resistant properties of the bait.

In preferred embodiments, the polymer compound is ethyl vinyl acetate. It will be appreciated by those skilled in the art that other polymers capable of achieving the same binding properties can also be used.

It is understood by the applicant that the polymer compound binds the bait ingredients and prevents baits from absorbing moisture and thus making the bait water resistant. This is an important property for long life bait compositions as the bait is typically in remote locations that are open to the environment including rain and humidity. By being water resistant, the bait will retain its structure and attraction for a longer period of time than would otherwise be the case.

According to a further aspect of the present invention there is provided a long life bait, attractive to vertebrate pests, substantially as described above wherein the bait remains attractive to the pest for at least one week. Most preferably, the bait remains attractive for at least one month. 6 Preferably, the bait is stable enough to last for at least one month and still be attractive to the pest. As kill traps are often left in remote locations for at least a week, the bait must be capable of retaining its structure and attractiveness during this period of time.

Preferably the bait is used in a kill trap. Preferably, the pest is attracted into the kill trap. Optionally, the bait can also be used in live-capture and leg hold traps as well as kill traps. The bait may also be used as a vehicle for a pesticide.

It will be appreciated by those skilled in the art that different bait compositions are used for different vertebrate species.

Preferably pests are selected from the group consisting of: mice, rats, stoats, ferrets, cats, possums, and combinations thereof.

Preferably, the lure compounds used are flavours or essences liked by the pest to be attracted. Such compounds include those selected from the group consisting of: orange flavouring, raspberry flavouring, aniseed flavouring, peppermint 15 flavouring, apple flavouring, cherry flavouring, plum flavouring, cinnamon flavouring, vanilla flavouring, bacon, bacon flavouring, garlic, garlic flavouring, fish oil, fish oil flavouring, natural extract 'digests', and combinations thereof.

Most preferably, for possum baits, the lure compounds are selected from the group consisting of: orange flavouring, raspberry flavouring, aniseed flavouring, 20 peppermint flavouring, apple flavouring, cherry flavouring, plum flavouring, cinnamon flavouring, and combinations thereof.

Most preferably, for rat applications, the lure compounds are selected from the group consisting of: vanilla flavouring, bacon, bacon flavouring, fish flavouring, and combinations thereof.

Intellectual Property Office of NZ 0 9 JUL 2003 Oiii&a Or fog 0 9 JUL 2003 Most preferably, for ferret applications, the lure compounds are selected from the group consisting of: fish oil, fish oil flavouring, bacon, bacon flavouring, natural extract digests, and combinations thereof.

Most preferably, for carnivorous pest applications, the lure compound is a natural 5 extract digest from the prey of that pest. By way of example, the applicant has found that rabbit 'digest' and/or chicken 'digest' is particularly advantageous for use in attracting stoats and ferrets.

Preferably, the palatable ingredients used are dependent on the pest to be attracted. For herbivore or omnivore pests, a cereal base is preferred. Most preferably, this cereal base includes main ingredients selected from the group consisting of: wheat, triticalli, golden syrup, treacle, maize, sugar, invert sugar, linseed meal, vegetable oil, and combinations thereof.

For carnivorous pests, a protein base of palatable ingredients is preferred. Most preferably, this protein base includes ingredients selected from the group IS consisting of: fish meal, cheese powder, chicken meal, meat meal, dried blood, egg powder and combinations thereof.

Preferably the bait also includes antioxidant compounds. The inclusion of such compounds avoids the bait becoming rancid. Typical bait formulations include natural or added fats, lipids and/or oils which oxidise and become rancid over 20 time. By inclusion of antioxidant materials, the stability is further increased. Most preferably, the antioxidant materials included are selected from the group consisting of: butylated hydroxyanisole (BHA), tert-butyl paracreosol (BHT), mono-tertiary-butyl-hydroquinone (TBHQ), propyl gallate, ethoxyquin, santoquin, and combinations thereof.

Preferably also, anti-microbial compounds are also included in the bait. Such compounds prevent mould and microbial growth generally on or within the bait. 8 Microbial growth can inhibit the attraction of the bait to the pest hence, particularly where the bait develops a water content over 12wt%, it has been found by the applicant to be advantageous to include such anti-microbial compounds.

In further embodiments of the present invention other attractant compounds are included, selected from the group consisting of: colourings such as blue dye or ultra-violet brightener; oils such as vegetable oils and fish oils; salts; preservatives; and combinations thereof.

Preservatives include the anti-oxidant compounds discussed above. Most preferably, additional preservative compounds that inhibit mould and bacterial growth are selected from the group consisting of: propionic acid, luprosil, bronopol, myacide, paraben (methyl, ethyl, propyl, or butyl), potassium sorbate, sodium benzoate, Suttocide®, Glydant®, Delvocoid®, Suttocide®, Solbrol-M, sodium metabisuphite, and combinations thereof.

In alternative embodiments, the bait also contains a pesticidal agent.

According to a further aspect of the present invention there is provided a method of manufacture of a long life bait composition including the steps of: (a) selecting at least one polymer compound selected from the group consisting of: a plastic; an elastomer; a resin; and combinations thereof; (b) mixing the polymer of step (a) with bait ingredients substantially as described above; (c) (d) heating the mixture of step (b); forming a pellet from the heated mixture of step (c). 9 Preferably, the polymer, when added to bait ingredients in step (b), is finely ground.

Preferably the temperature to which the mixture is heated in step (c) is greater than the melting point of the polymer selected. Heating is carried out to melt the 5 polymer compound.

Preferably the pellet is formed by either extrusion or injection moulding.

Preferably, if an extruder is used in step (d), it is of a single or twin screw type.

Most preferably, the pellet is in the shape of a cylindrical block with a hole in the centre. A hole enables the trapper to thread the bait onto a trip wire or similar 10 trigger device. It will be appreciated by those skilled in the art that other structures of bait are also possible are dependent on the preferred means of trapping e.g. square blocks.

According to a further aspect of the invention there is provided the use of a long life bait composition substantially as described above in pesticidal applications.

The use of long-life polymer baits in kill traps provides a very cost-effective means of controlling pests. For example, to achieve an 80% kill of ferrets with leg-hold traps is likely to require 11 man-days continuous trapping at a cost of $2750/10 km2; compared to 3 man-days trapping with kill traps during a 2-week period at a cost of $750/10 km2. Infrequent visits to kill traps is also likely to 20 confer other advantages on the control of predators; such as less human scent (that deters some carnivores) in the vicinity of traps, and less disturbance and/or displacement of pests from trap lines.

It will be appreciated from the above description that there is provided a long life bait composition that is capable of remaining attractive to a vertebrate for at least one month. Such a composition is of considerable value in reducing the cost of trapping operations as such long life baits require less labour time from trappers.

BEST MODES FOR CARRYING OUT THE INVENTION The above description will now be further described by the examples described below.

Example 1 -Bait Manufacture A possum bait composition found by the applicant to be particularly useful in the present invention includes the following ingredients: Ingredient Amount (wt %) Finely ground wheat 45wt% Flour 5wt% Maize 26.9wt% Polymer (ethyl vinyl acetate) 12wt% Soya bean oil 5wt% Golden syrup 5wt% Raspberry flavouring 0.75wt% Blue dye 0.15wt% Antimicrobial agent (Myacide or 2- bromo-2-nitropropane-l,3-diol, bronopol) 0.03wt% Propyl gallate 0.008wt% Propylene glycol 0.1 wt% Salt 0.1% Total: -100% 11 The above ingredients are thoroughly mixed and heated to above the melting point of the polymer (approximately 92°C). Once the mixture is thoroughly heated and mixed, the mixture is then extruded through a single or twin screw extruder into cylindrical blocks.

It will be appreciated that a wide variety of different amounts of each compound can be used. By way of example the main components (macro ingredients) of the possum bait include: Possum Bait Macro Ingredients Ingredient Amount (wt%) Wheat 0-88% Treacle 0-20% Golden Syrup 0-20% Maize 0-60% Sugar 0-30% Vegetable Oil 0-10% By way of further example the main components (macro ingredients) of rat and/or mice bait includes: Rat and Mice Bait Macro Ingredients Ingredient Amount (wt%) Wheat 0-93% Golden Syrup or Treacle 0-20% Maize 0-60% Sugar 0-30% Linseed meal 0-20% Invert Sugar 0-20% Animal Fats 0-15% Vegetable Oil 0-10% 12 By way of further example the main components (macro ingredients) of a ferret, stoat and/or cat bait includes: Ferret Stoat Cat Bait Macro Ingredients Ingredient Amount (wt%) Fish Meal 0-88% Chicken Meal 0-60% Egg powder 0-10% Cheese Powder 0-60% Meat Meal 0-30% Animal Fat 0-10% 'Digest' 0-20% Dried Blood 0-10% Fish Oil 0-10% Example 2 - Palatability Highly palatable bait ingredients are used to formulate baits.

The palatability of bait ingredients was measured by presenting 20 individually-caged animals with paired trays containing test ingredient(s) and control bait 10 (selected as an industry standard).

Palatability is determined as the weight of test bait eaten relative to total bait consumption (i.e., test + control). If the palatability index is >50% then more test bait is eaten than control, and ingredients are likely to increase palatability. However, if palatability is <40% then the ingredient(s) are likely to reduce 15 palatability. 13 Palatability of different protein additives in ferret baits Protein meal assessed Palatability (%) Egg powder 62.6 Chicken-meal 64.5 Cheese powder 74.0 Rabbit 'digest' 78.5 Meatmeal 50.6 Milkpowder 48.0 Casein powder 44.0 As can be seen from the results shown in the table above, various ingredients have been demonstrated to make baits highly palatable to different pests (e.g., cheese powder is known to be highly palatable to ferrets).

Example 3 - Lure Compounds The effectiveness of olfactory lures at attracting a pest species is determined by measuring the frequency that traps catch possums baited with different types of lure. Lures that are sensed quickly by a pest and then investigated are those that are typically included in baits.

The results as shown in the table below show that in a forest location, aniseed and raspberry were more effective lures than apple and orange. 14 The number of possums caught in 'Set-n-Forget' traps using different types of lure, and the percentage trap-catch per night Type of Lure No. of possums caught Number of trap nights Catch per trap-night (%) Aniseed 37 150 24.7 Raspberry 36 146 24.7 Apple 24 150 16.0 Orange 146 13.7 In a further trial the capture efficiency of conventional leg-hold traps (lured with flour) and kill traps (lured with polymer baits) were compared during a weeks trapping of a low-density possum population. The capture efficiency of traps containing polymer baits was significantly higher than the capture efficiency of leg-hold traps lured with flour as shown in the table below.

Frequency of capture of leg-hold traps lured with flour and kill traps lured with polymer baits in a low-density possum population Type of trap Type of lure Percentage of traps catching (%) Leg-hold Flour 12 Kill trap Polymer bait 24 In a further trial, the capture efficiency of a blue visual lure was compared with the capture efficiency of white bait. Results showed that significantly more possums were caught with the blue lure.

Frequency of capture of kill traps with lures colored blue or white.

Type of trap Colour of lure Percentage of traps catching (%) Kill trap Blue 32 Kill trap White 22 Example 4 - Stability The stability (attractiveness) of different baits containing different lures was checked using captured pests. The results shown in the table below show that palatability of bait stored in a humid field situation is maintained for as long as 3 weeks.

The palatability of polymer baits before and after 3 weeks storage in the field Type of lure Time in open (weeks) Palatability (%) Aniseed 0 58.2 Raspberry 0 50.0 Aniseed 3 47.2 Raspberry 3 46.8 Aniseed 13 55.0 16 Aspects of the present invention have been described by way of example only and it should be appreciated that modifications and additions may be made thereto without departing from the scope thereof as defined in the appended claims.

Sntsffectiiaf r".r- . - 'l" 0 9 JUL 2003 rscsivsd 1. A long life bait, attractive to mammalian vertebrate pests, which includes: lure ingredients; palatable ingredients; and characterised in that the bait also includes at least one polymer compound selected from the group consisting of: a plastic; an elastomer; a resin; and combinations thereof. 2. A long life bait, as claimed in claim 1, wherein the polymer is capable of binding the bait ingredients together. 3. A long life bait as claimed in claim 1 or claim 2 wherein the polymer chosen increases water resistant properties of the bait. 4. A long life bait as claimed in any one of the above claims wherein the polymer is ethyl vinyl acetate.

. A long life bait as claimed in any one of the above claims wherein the bait remains attractive to the pest for at least one week. 6. A long life bait as claimed in any one of the above claims wherein the bait remains attractive to the pest for at least one month. 7. A long life bait as claimed in any one of the above claims wherein the bait is used in kill trap applications. 8. A long life bait as claimed in any one of claims 1 to 6 wherein the bait is used in live-capture and leg hold traps. 17

Claims (1)

1. WHAT WE CLAIM IS: 18 10. A long life bait as claimed in any one of the above claims wherein the pests are selected from the group consisting of: mice, rats, stoats, ferrets, cats, possums, and combinations thereof. A long life bait as claimed in any one of the above claims wherein the lure compounds include those selected from the group consisting of: orange flavouring, raspberry flavouring, aniseed flavouring, peppermint flavouring, apple flavouring, cherry flavouring, plum flavouring, cinnamon flavouring, vanilla flavouring, bacon, bacon flavouring, garlic, garlic flavouring, fish oil, fish oil flavouring, natural extract 'digests', and combinations thereof. A long life bait as claimed in any one of the above claims wherein, for luring possums, the lure compounds are selected from the group consisting of: orange flavouring, raspberry flavouring, aniseed flavouring, peppermint flavouring, apple flavouring, cherry flavouring, plum flavouring, cinnamon flavouring, and combinations thereof. A long life bait as claimed in any one of the above claims wherein, for luring rats, the lure compounds are selected from the group consisting of: vanilla flavouring, bacon, bacon flavouring, fish flavouring, and combinations thereof. A long life bait as claimed in any one of the above claims wherein, for luring ferrets, the lure compounds are selected from the group consisting of: fish oil, fish oil flavouring, bacon, bacon flavouring, natural extract 'digests', and combinations thereof. Intellectual Property Office of NZ 0 9 JUL 2003 19 A long life bait as claimed in any one of the above claims wherein, for luring carnivorous pests, the lure compound is a natural extract digest from the prey of that pest. A long life bait as claimed in any one of the above claims wherein, for herbivore or omnivore pests, the palatable ingredients include cereal based ingredients. A long life bait as claimed in claim 15 wherein the cereal base includes ingredients selected from the group consisting of: wheat, triticalli, golden syrup, treacle, maize, sugar, invert sugar, linseed oil, vegetable oil, and combinations thereof. A long life bait as claimed in any one of claims 1 to 14 wherein for carnivorous pests the palatable ingredients include protein based ingredients. A long life bait as claimed in claim 17 wherein the protein based ingredients includes ingredients selected from the group consisting of: fish meal, cheese powder, chicken meal, meat meal, dried blood, egg powder, and combinations thereof. A long life bait as claimed in any one of the above claims wherein the bait also includes at least one antioxidant compound. A long life bait as claimed in claim 19 wherein the antioxidant compound included is selected from the group consisting of: butylated hydroxyanisole (BHA), tert-butyl paracreosol (BHT), mono-tertiary-butyl-hydroquinone (TBHQ), propyl gallate, ethoxyquin, santoquin, and combinations thereof. Intellectual Propertv Office of NZ C 9 JUL 2003 20 21. A long life bait as claimed in any one of the above claims wherein the bait also includes at least one anti-microbial compound. 22. A long life bait as claimed in any one of the above claims wherein farther compounds are included which are selected from the group consisting of: blue dyes, ultraviolet brightener; vegetable oils, fish oils, salts, preservatives, and combinations thereof. 23. A long life bait as claimed in claim 22 wherein the preservative compounds are selected from the group consisting of: propionic acid, luprosil, bronopol, myacide, paraben (methyl, ethyl, propyl, or butyl), potassium sorbate, sodium benzoate, sodium hydroxymethylglycinate, dimethylol dimethyl hydantoin, methyl para-hydroxybenzoate, sodium metabisuphite, and combinations thereof. 24. A long life bait as claimed in any one of the above claims wherein the bait also contains a pesticidal agent. 25. A method of manufacture of a long life bait composition including the steps of: (a) selecting at least one polymer compound from the group consisting of: a plastic; an elastomer; a resin; and combinations thereof; (b) mixing the polymer of step (a) with the lure and palatable ingredients as claimed in any one of claims 1 to 24; (c) heating the mixture of step (b); (d) forming a pellet from the heated mixture of step (c). Office <* H 3 0o 2$3 ^ cSz ^ii V- 21 26. A method of manufacture of a long life bait composition as claimed in claim 25 wherein the polymer, when added to bait ingredients in step (b), is finely ground. 27. A method of manufacture of a long life bait composition as claimed in claim 25 or claim 26 wherein the temperature to which the mixture is heated in step (c) is above the melting point of the polymer selected. 28. A method of manufacture of a long life bait composition as claimed in any one of claims 25 to 27 wherein the pellet is of a cylindrical block shape with a hole in the centre. 29. A method of manufacture of a long life bait composition as claimed in any one of claims 25 to 28 wherein the pellet is formed by a process or extrusion or injection moulding. 30. The use of a bait as claimed in any one of claims 1 to 24. 31. A bait substantially as hereinbefore described and with reference to Examples 1 to 4. 32. A method of manufacture of a bait substantially as hereinbefore described and with reference to Examples 1 to 4. 33. The use of a bait substantially as hereinbefore described and with reference to Examples 1 to 4. PEST-TECH LIMITED Intellectual Property by their authorised agents Office of KZ JAMES & WELLS 0 9 JUL 2503 'Wsttion