AU703522B2 - Compound and method for repelling browsing animals from plants - Google Patents

Description

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AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION STANDARD PATENT Applicant(s): RURAL INDUSTRIES RESEARCH AND DEVELOPMENT

CORPORATION

EGG INDUSTRY COOPERATIVE LTD A.C.N. 059 563 030 THE SECRETARY TO THE DEPARTMENT OF 4NERVATION NATURAL RESOURCES t E~ ronmek Invention Title: COMPOUND AND METHOD FOR REPELLING BROWSING ANIMALS FROM PLANTS The following statement is a full description of this invention, including the best method of performing it known to me/us: c 2 COMPOUND AND METHOD FOR REPELLING BROWSING ANIMALS FROM PLANTS This invention relates to methods and compounds for repelling browsing animals from plants, and in particular but not limited to a method and compound for repelling rabbits and/or wallabies from tree seedlings.

Damage caused by browsing animals to trees is a world-wide concern to the forest industry and land-holders attempting to propagate trees on private land for soil stabilisation, wind-breaks, stock shelter, salinity mitigation or land reforestation. Twenty percent of all plantation failures are directly attributed to the action of such "browsing mammals" in the US states of Oregon and Washington. In the Yarram area of Victoria, browsing animals have been implicated in plantation losses of up to 19%.

Where European rabbits (Or3rctolagus cuniculus) occur within or on the margins of plantations, they can severely damage both seedlings of eucalyptus and Pinus radiata by a process of defoliation of leaves, bark-stripping or partial or complete removal of woody tissue. In addition, they are known to damage larger seedlings and saplings by the 25 gnawing or stripping of bark. Seedling damage by rabbits will quite often result in the total removal of the i: seedling or its death. Such damage to Pinus radiata seedlings has been observed in New Zealand plantations.

Damage to Tasmanian timbers by rabbits has also been observed. Other Lagomorphs, such as the snowshoe hare (Lepus americanus) also impose high levels of browsing damage upon trees and shrubs which retard regrowth of coniferous forest.

35 Browsing animals in Victorian plantations were until recent years predominantly managed by the use of poison baiting ;\MEt~ROl\holFPS\vlCky\RBBp\liC~'l\bl.lW 2/09/97 9 C- 3with 1080 (fluoroacetic acid) treated carrots, delivered either by aerial baiting or trail baiting. Growing concern about the target specificity of such techniques prompted an investigation of alternative methods of browsing animal mitigation, which led to the current invention.

An effective repellent should ideally be non-toxic, easy to apply to seedlings and most importantly, the repellent effect should persist for a period of time which substantially reduces the vulnerability of the seedling to browsing animals.

Repellents containing an olfactory aversion agent are well known. In the case of rabbits, egg products such as powdered egg have been known to deter rabbits from eating plants. The egg product is mixed with an adherent such as paint or other synthetic products such as "Rhoplex" and applied to the plant by spraying, dipping or painting.

Controlled studies by the inventors of the current application confirm that repellents based solely on egg products offer some repellent effect against rabbits, but little if any repellent effect against wallabies. A further disadvantage of repellents based on an olfactory aversion agent is that the strength of the unpleasant smell or taste diminishes fairly rapidly so that the effective life of such repellents is limited, in the case of egg- 25 based repellents to about 10-30 days. The repellent effect is thought to originate in putrefaction of a constituent of the egg, either fatty acids or proteinaceous substances.

It is an object of the current invention to provide a repellent with improved repelling properties, particularly to rabbits and/or wallabies.

It is an alternative object of the current invention to stafky keepspbrowsing compt au 201295 4 provide a repellent with an improved persistence of repellent effect.

Therefore in accordance with a broad aspect of the invention there is provided a compound for repelling browsing animals from plants comprising: a masticatory aversive agent; and (ii) an adherent to promote adhesion of the compound to the plants.

In accordance with a further aspect of the invention there is provided a method of repelling browsing animals, the method comprising applying said compound to the foliage or stem of the plant.

Preferably, the adherent is applied to the plant in a first step and the masticatory aversive agent is then applied onto the adherent-coated plant, to produce the compound in situ.

The compound may also contain an olfactory signalling agent whereby the animals can learn by smell or taste to avoid suffering the masticatory aversion without chewing the o. plant. The olfactory agent may in addition be an olfactory aversive agent which directly repels the animals for at least an initial period after said application. Preferably the olfactory agent contains egg.

Preferably also, the masticatory aversion agent is a hard gritty substance. Preferably still, the hard gritty substance is particles of silicon carbide.

The adherent may be any suitable material with low phytotoxicity for the particular plant species intended to be protected. For example, the product available commercially under the name Primal AC-2235 (Rhoplex) has H:'pauad\Keep\pecL\brwxing. :cmplnau 4056:1-.doc been found to be suitable for application to Pinus radiata 'and to a number of Australian tree species.

In order that the invention can be more clearly ascertained, a non-limiting example of a preferred e:mbodiment will now be described with reference to the accompanying figures, where: Figure 1 is a plot of test results showing the repellent effect of a repellent made according to the preferred embodiment, code named WR-1, in relation to repelling wallabies from seedlings of Eucalyptus globulus; and Figure 2 is a plot of test results showing the effectiveness of WR-1 in deterring rabbits from damaging seedlings from Pinus radiata.

The preferred embodiment (WR-1) consists of a liquid component and two solid components. 100ml of the liquid component comprises 50ml of the adherent agent known as Primal AC-2235 (formally Primal AC-235M) or RhoplexT, which is sold commercially by Rohm and Haas, together with 50ml of water. Rhoplex contains acrylic polymers such as butyl acrylate and methyl methacrylate as active O:go constituents and its normal commercial application is as an additive to paint or floor polish to improve adherence to S: the surface which is coated.

The solid components of WR-1 are roughly equal quantities by weight of whole egg powder as an olfactory signalling 30 agent and silicon carbide grit as the masticatory aversive agent. The whole egg powder is mixed with the liquid component in the ratio of 20 grams for every 100 ml and the resultant product may be sprayed onto the plants. Painting or dipping is also effective. The silicon carbide grit is then sprinkled onto the coated plants to produce the compound in situ. The compound dries as a clear film onto the plant.

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6 The optimum grain size of the silicon carbide grit was found to be, in the case of wallabies, commercial ie. the grains will pass through a square mesh of 60 holes per inch. However grades of 20, 30 and 100 have also been observed to have beneficial effect.

The grit may alternatively be pre-mixed with the egg powder and liquid component, but if this is done spray application is not possible, and care must be taken to avoid settling of the grit to the bottom of the container from which the compound is taken.

Rhoplex and egg powder are already known, as discussed above, as a repellent for rabbits. Acrylic paint and egg powder is also a known rabbit repellent. Field test by the current inventors have confirmed that the major active repellent agent in egg and Rhoplex or egg and paint repellents is the egg component The components have been tested separately and Rhoplex has been found to have a very mild repellent effect, acrylic paint no significant effect and egg powder a fairly strong repellent effect.

Field trials were conducted by the current inventors to S: assess the effectiveness of WR-1 in comparison with known egg based repellents as exemplified by egg and paint.

Separate compounds for rabbits and wallabies were constructed. The rabbit compound was 2 hectares in size containing approximately 50 rabbits within the boundary.

The boundary was comprised of electric fencing and rabbitproof wire. The wallaby compound was a 5 hectare compound with 7 wallabies within its boundary. The fence surrounding the compound was comprised of an 8 foot high cyclone chain mesh. This colony of wallabies has been stable for approximately 12 months, with reproduction now occurring.

staffihky keepspecbowsing ccnil au 20 12 I P -Clll 1 7 The methodology for the experiments was the same for both rabbit and wallaby compounds. The rabbit compound contained Pinus radiata seedlings and the wallaby compound contained Eucalyptus globulus seedlings. In each compound, a rectangular area was planted with 192 seedlings. The 192 seedlings were treated according to four different methods, 48 seedlings for each method. The seedlings were planted in an alternating pattern according to method of treatment, thereby allowing seedlings treated according to each method to be spread throughout the rectangular area and offering animals a free choice of nearby seedlings treated by each method at every point in the rectangle. The four methods of treatment were: 1. No treatment (control) 2. Egg and acrylic paint 3. WR-1 containing 30-grade silicon carbide grit 60-grade was later found to be preferable) 4. with 30-grade silicon grit.

25 AD-3 is a substance which is the subject of a separate patent application. A batch of AD-3 may be made by mixing together 10 kg egg powder, 33 kg petroleum jelly, and 66 kg Canola oil. For each batch of AD-3, approximately 10 kg silicon carbide grit is used, sprinkled onto the plant in situ as with WR-1.

The experiment was arranged so that the target animals would be confronted with a free choice of treated or untreated seedlings. Each seedling was inspected 35 individually every second day and a damages score assigned to the seedling. The scoring system associated with each \\MELBO I\ e'\Vv-ky I I I. ar.i-on I, L 1 -ff 2 1(5'7 a I-- 8 seedling was as follows: SCORE DESCRIPTION OF DAMAGE 0 no damage 1 seedling leaf area defoliated, less than 30% of total leaf area 2 seedling leaf area defoliated, greater than of total leaf area 3 stem cut above the mid line, including apical bud removal 4 total removal of seedling In Figure 1, the results for the wallaby compound in relation to Eucalyptus globulus seedlings are shown. It can be seen that the performance of egg and paint, plotted as squares, was roughly comparable to that of the control S 25 plotted as diamonds. Accordingly, egg and paint was found to have no significant repellent effect for wallabies. AD- "3 and silicon carbide, plotted as crosses, had deleterious effects on the plant, due to the phytotoxicity of AD-3 to o. Eucalyptus globulus.

WR-1 plotted as triangles was very effective.

In Figure 2 the results for the rabbit compound in relation to Pinus radiata are shown. The control is plotted again 35 as solid diamonds, egg and paint as triangles, AD-3 as crosses and WR-1 as squares (both with silicon carbide).

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9 It can be seen that up to approximately 35 days after application, egg and paint, WR- and AD-3 are all producing a significant repellent effect when compared with the control. After this time, egg and paint apparently loses its effectiveness and the damage score increases roughly in line with the increase in damage score of the control.

This supports a hypothesis that the olfactory aversion produced by the egg and paint was exhausted after 35 days in the environment. By contrast, both AD-3 and WR-l maintain their repellent effect and the damage score increases at a much slower rate, if at all. Extended trials have verified that WR-l retains its repellent effect for up to 90 days.

In a separate study it has been found that AD-3 alone (without silicon carbide) is not an effective olfactory repellent for wallabies, for which the canola oil appears to be an attractant, but is effective as a wallaby repellent for Pinus radiata seedlings when used in conjunction with the silicon carbide.

While the theory of operation of the invention is not entirely understood, it is believed that the invention produces a long lasting repellent since the primary 25 aversion agent is a masticatory aversion which because it is textural in nature remains as long as the repellent .o adheres to the plant. While it is expected that a useful repellent is provided by a masticatory aversive agent and adherent alone, it is thought in respect of the preferred embodiment WR-I that the animal associates the olfactory signal produced by the olfactory signalling agent with past unpleasant experiences provided by the masticatory aversive agent, and learns to avoid such a plant before causing o significant damage. It is also believed that in the case of WR-1, the egg powder contained in it loses any olfactory repellent effect for rabbits after approximately 35 days, :\MELBOl\hr me;\vtc-ky\Rerp\speci\t ruw

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10 but the masticatory aversion remains and the remaining odour or taste emitted from the egg powder assists to provide an olfactory signalling agent to warn the rabbit of the presence of the masticatory aversion agent. In the case of wallabies the results with egg and paint confirm that the egg powder itself is not at all an olfactory aversive agent, and it is therefore believed that for wallabies the egg powder in WR-1 may act solely as an olfactory signalling agent to warn of the presence of the masticatory aversive agent.

Masticatory aversive agents other than silicon carbide have been tried by the current inventors, and it has been found that all such hard gritty substances produce a significant deterrent effect. Ordinary sand is effective, and provides *o 15 a cheap alternative to silicon carbide, but its effectiveness is not as great. This is believed to be due to the fact that sand is less hard than silicon carbide and therefore produces a less unpleasant experience for the animal when chewing. It may be anticipated that any 20 material which is hard and gritty, such as emery powder, o°°i would be effective as a masticatory aversive agent, and that different substances may be optimally effective as masticatory aversive agents for different browsing animals.

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Modifications may be made to the invention as would be 25 apparent to a person skilled in the art of repellent o design. For example, any suitable adherent may be provided which effectively results in the adhesion of the repellent to the leaves of a plant. It is not necessary that an adherent be an adhesive as such and may merely act as a surfactant to overcome the waxy repulsion of liquids provided by plants, thereby allowing a film to dry on the surface of the leaf. Further, any suitable agent may be contemplated and tested to provide the preferred feature of an olfactory signalling agent. These and other staff iky keep spec brwsig comro au 20 1295 11 modifications may be made without departing from the ambit of the invention, the nature of which is to ascertained from the foregoing description, the claims and the figures.

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Claims (18)

1. A compound for repelling browsing animals from plants comprising: a masticatory aversive agent; and (ii) an adherent to promote adhesion of the compound to the plants.

2. A compound as claimed in claim 1 further comprising an olfactory signalling agent whereby the animals can learn by smell or taste to avoid suffering the masticatory aversion without chewing the plant.

3. A compound as claimed in claim 2 wherein the olfactory signalling agent is an olfactory aversive agent which directly repels the animals for at least an initial period after said application. 15

4. A compound as claimed in claim 3 wherein the olfactory aversive agent contains egg or an extract of egg.

A compound as claimed in any one of the preceding claims wherein the olfactory aversive agent contains canola oil.

6. A compound as claimed in any one of the preceding claims 20 wherein the masticatory aversion agent is a hard gritty substance.

7. A compound as claimed in claim 6 wherein the hard gritty substance comprises particles of silicon carbide.

8. A compound as claimed in claim 7 wherein the particles can pass through a square mesh of 20 holes per inch.

9. A compound as claimed in claim 7 wherein the particles staff iky keepspecibrowsir' comp au 20 12 I 13 can pass through a square mesh of 30 holes per inch.

A compound as claimed in claim 7 wherein the particles can pass through a square mesh of 60 holes per inch.

11. A compound as claimed in claim 7 wherein the particles can pass through a square mesh of 100 holes per inch.

12. A compound as claimed in any one of the preceding claims wherein the adherent contains acrylic polymers.

13. A compound as claimed in any one of the preceding claims wherein the adherent contains petroleum jelly.

14. A compound as claimed in any one of the preceding claims, further comprising canola oil.

A method of repelling browsing animals, comprising applying a compound as set forth I \ny one of claims 1 to 14 to the foliage or stem of the plant.

16. A method as claimed in claim 15, where the compound is formed in situ on the plant by applying the masticatory aversive agent to the plant after applying the adherent to 25 the plant. e

17. A compound for repelling browsing animals substantially as hereinbefore described with reference to example 3. 9 e 9 I\ hc(II r-n Wwky',Fv:E l, I N! r bx' -S I i 'rJ. au l Z" I! q? 119111 14

18. A method of repelling browsing animals substantially as hereinbefore described with reference to example 3. Dated this 2nd day of September 1997 RURAL INDUSTRIES RESEARCH AND DEVELOPMENT CORPORATION EGG INDUSTRY COOPERATIVE LIMITED THE SECRETARY TO THE DEPARTMENT OF NATURAL RESOURCES AND ENVIRONMENT By their Patent Attorneys GRIFFITH HACK Fellows of the Institute of Patent Attorneys of Australia *e* e r o c i p? \\MELBOlilr-ro~ riwnlnp -i ir2i~ au. 1 1 L(i~ ABSTRACT A compound for repelling browsing animals from plants is described. The compound contains a masticatory aversive agent and an adherent to promote adhesion of the compound to the plants. The masticatory aversive agent may comprise a hard gritty substance such as particles of silicon carbide, and the adherent may comprise acrylic polymers such as butyl acrylate and methyl methacrylate. The compound may also contain whole egg powder as an olfactory signalling agent. The compound may be produced in situ on the plant by applying the particles of silicon carbide to the plant after application of the adherent to the plant. OOU049 S.. e* e* o e *o staftiky;keepspecabrowsng compiau 20 12