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Title:
RADIATION STERILISED SEED BAIT
Document Type and Number:
WIPO Patent Application WO/2002/032230
Kind Code:
A1
Abstract:
This invention relates to a method of preparing a bait comprising subjecting whole seeds to a source of gamma radiation to provide sterilised whole seeds and applying an active agent to said sterilised whole seeds.

Inventors:
STAPLES LINTON DREW (AU)
Application Number:
PCT/AU2001/001346
Publication Date:
April 25, 2002
Filing Date:
October 19, 2001
Export Citation:
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Assignee:
APPLIED BIOTECHNOLOGIES PTY LT (AU)
STAPLES LINTON DREW (AU)
International Classes:
A01N25/00; A23B9/04; A23L3/26; (IPC1-7): A23B9/04; A23B9/06; A23L3/26; A01N25/08; A01N65/00
Foreign References:
US4670274A1987-06-02
Other References:
YARDIN M.R. ET AL.: "Development of high quality carrier materials for field delivery of key microorganisms zsed as bio-fertilisers and bio-pesticides", RADIATION PHYSICS AND CHEMISTRY, vol. 57, March 2000 (2000-03-01), pages 565 - 568
LEITAO J. ET AL.: "Preventive measures for microflora and mycotoxin production in foodstuffs", ARCHIVES OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY, vol. 19, 1990, pages 437 - 446
DATABASE WPI Derwent World Patents Index; Class A01, AN 1993-141779
Attorney, Agent or Firm:
Caine, Michael J. (Victoria 3000, AU)
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Claims:
THE CLAIMS
1. A method of preparing a bait comprising subjecting whole seeds to a source of gamma radiation to provide sterilised whole seeds and applying an active agent to said sterilised whole seeds.
2. A method according to claim 1 wherein the whole seeds are cereal grains.
3. A method according to claim 2 wherein the cereal grains are oats or wheat.
4. A method according to claim 2 wherein the cereal grains are corn.
5. A method according to claim 4 wherein the corn is in the form of a corn cob.
6. A method according to any one of claims 1 to 5 wherein the active agent of the bait is selected from the group consisting of hormones, hormone antagonists, vaccines, metal phosphides, anticoagulants and toxic chemicals.
7. A method according to claim 6 wherein the active agent is zinc phosphide.
8. A method according to any one of claims 1 to 7 wherein the bait includes an attractant.
9. A method according to any one of claims 1 to 8 wherein the whole seeds are subjected to gamma radiation at a level of about 5 kilograys.
10. A method for delivering a bait to an area exposed to the environment which method comprises dispersing throughout said area a bait comprising sterilised whole seeds in association with an active agent, said whole seeds being sterilised by exposure to gamma radiation.
Description:
NOVEL BAIT This invention relates to baits, and in particular to baits which comprise a whole seed treated with an active agent.

The application of baits to areas exposed to environmental factors represents a substantial problem to agriculturalists, especially when large areas of land need to be treated with bait.

In order to apply a bait to larger areas it is often necessary to use seed spreaders or to apply the bait by hoppers mounted on aircraft. Due to problems with wind dispersal, such poisons are preferably contained within pellets or granules, rather than dusts. Since most target animals are attracted to baits which contain products derived from cereal grains, it would be particularly convenient to provide the poison in a form which is associated with such a grain carrier.

A problem with using whole grains as a carrier for active poisons is that the grains can germinate and cause contamination of crops of the type represented by the grains used for the bait. Moreover, the commercial supply of gran may contain low quantities of weed seed contaminants that could give rise to infestations of weeds in treated areas due to the transfer of viable weed seeds in the bait product. This problem has been addressed in the past by using cracked grain which is incapable of germinating but it remains possible in such preparations that small seeds of weed species contaminating the grain could escape crushing by the cracking process. Several problems are associated with the use of cracked grain. The particles containing the poison do not have a uniform size and include significant amounts of dust and husks which make it difficult to apply the poison at measurable rates. There is also a risk that some of the grain particles could remain intact and therefor germinate causing some contamination of the crop. It is an object of the present invention to overcome or at least alleviate one or more of the above-mentioned problems with the prior art.

Accordingly the present invention provides a method of preparing a bait comprising subjecting whole seeds to a source of gamma radiation to provide sterilised whole seeds

and applying an active agent to said sterilised whole seeds.

In another aspect the invention provides a method for delivering a bait to an area exposed to the environment which method comprises dispersing throughout said area a bait comprising sterilised whole seeds in association with an active agent, said whole seeds being sterilised by exposure to gamma radiation.

The term"bait"as used herein refers to a pest control agent which is palatable and at least partially edible by a target pest, and which is associated with an active agent which affects the physiology of the target pest. Generally the bait will comprise a palatable and edible carrier in association with an active agent. The active agent may be any suitable agent which affects the physiology of the target pest in a desired manner. For example the active agent may be a compound or composition capable of affecting reproductive performance of the target pest. For example the active agent may contain or consist of a hormone or hormone antagonist. The active agent may also be a vaccine. For example the active agent may be a vaccine against foot and mouth disease, which would be particularly useful in the case of wild pigs, or a vaccine against rabies in the case of wild dogs. The active agent may be a metal phosphide, such as zinc, magnesium or aluminium phosphides.

These phosphides, particularly zinc phosphide, are useful when the target pests are rodents.

The active agent may also be an anticoagulant which interferes with the blood clotting ability of the target pest. Examples of such anticoagulants include those of the coumerin class, such as warfrarin, coumatetralyl, bromadiolone and brodifacoum, and those of the indole class, such as pindone, chlorophacinone and diphacinone. Other active agents include toxic chemicals, such as fluoroacetic acid, also known as 1080 and strychnine.

The terms"active agent"and"poison"are used interchangeably throughout this specification. The active agent may be a mixture of two or more active agents. The bait may also contain the additives known to the art, such as colourants and attractants, such as flavourants or scents.

The palatable and edible carrier in respect of the bait of the present invention is a whole seed product, said whole seeds having been sterilised by exposure to gamma radiation.

Seeds may be any seed which, in the absence of sterilisation, would have the potential to germinate. The whole seeds may be cereal grains such as wheat, oats, barley or corn, legume seeds such as peas, grass seeds such as millet etc. or any other suitable seed product. The seeds may be loose seeds, aggregated seeds, or in the form of a seed head, such as an ear of wheat or a cob of corn. Corn cobs and pods of peas are particularly suitable for larger pests, such as wild pigs. The seeds are preferably cereal grains, such as oats or wheat.

The active agent may be associated with the whole seed in any manner known to the art.

For example, a water soluble active agent may be dissolved in water and sprayed on the seeds which are then subjected to a drying step. In the case of granules and pellets, the active agent may be incorporated in the composition prior to or during the granulation or pelletisation processes. The active ingredient may be a dry powder that is dispersed into a carrier or binding solution and then dispersed throughout or onto the outer surface of the palatable carrier by any appropriate mixing, tumbling or spraying technique common in the art.

The grains may be subjected to gamma radiation using any suitable radiation equipment, such as equipment used to treat materials by passing by or temporarily holding close to a radioactive isotope that releases gamma radiations such as 60Cobalt or equipment that exposes materials to sources of radiation such as an x-ray tube or particle accelerator.

Generally the amount of radiation will be in the range of 5 to 50 kilogray. It is especially preferred to subject the grains to gamma radiation in an amount of about 5 kilograys. The gamma rays are preferably derived from a 60Cobalt source.

The baited whole seeds of the present invention may be dispersed using any method known to the art. If in loose form they may be disposed using conventional seed spreaders, or alternatively can be applied from aircraft using aircraft hoppers. Since whole seeds/grains are used the amount of dust is negligible. In view of the uniform size of the seeds they can be conveniently applied to crops and other areas exposed to the environment at measurable rates using conventional seed spreaders or aircraft hoppers. It

is also possible to apply the bait by dispersing sachets containing the treated seeds to the target area.

The treated cereal grains according to the present invention are particularly useful in the control or eradication of pests such as mice, rats and rabbits.

The sterilisation of the seeds with gamma radiation also provides the added advantage of increasing the storage stability of baits with high moisture content, such as corn cobs or pods of peas.

The invention will now be described with reference to the following examples which illustrate a preferred embodiment of the invention. However it is to be understood that the following descriptions are not to supersede the generality of the preceding description of the invention.

Example 1 Quantities of oats and wheat were subjected to gamma radiation provided from a 60Cobalt source in an amount of 5 kilograys. This treatment rendered the grains sterile. Zinc phosphide was then applied to the grains by first dispersing the zinc phosphide in vegetable oils and then adding the slurry to sterilised grain in a tumbling mixer.

Example 2 25 grams of the grains prepared in accordance with Example 1 where placed in a sachet composed of cellulose film.

Example 3 Normal whole wheat grains were irradiated with gamma radiation from a 60Co source at a radiation dose of 5 kilogray. The wheat was then subjected to germination conditions to give the following germination results: Normal seedlings 0% Abnormal seedlings (unviable) 93% Dead seeds 7% Throughout this specification and the claims which follow, unless the context requires otherwise, the word"comprise", and variations such as"comprises"and"comprising", will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.

Those skilled in the art will appreciate that the invention described herein is susceptible to variations and modifications other than those specifically described. It is to be understood that the invention includes all such variations and modifications which fall within the spirit and scope. The invention also includes all of the steps, features, compositions and compounds referred to or indicated in this specification, individually or collectively, and any and all combinations of any two or more of said steps or features.