A METHOD AND DEVICE FOR PREVENTING THE ADVANCE OF INSECTS

Abstract: A method of preventing the advance of insects of the kind which move on the ground, on parts of biological plants, buildings or the like, wherein a mechanical barrier is placed in the path of the insects. The barrier has the form of a material composed of a large number of thin fibres. According to the invention, there is used flexible, thread-like fibres which are loosely placed together or loosely joined together to form a manageable material composition, such that when coming into contact with the material, an insect can experience the fibres as being the threads of a cobweb and be repelled thereby. The invention also relates to a device for use in carrying out the method.

Description: A Method and Device for Preventing the Advance of Insects The present invention relates to a method of preventing or deterring the advance of insects of the kind which move on the ground, on parts of biological plants, on buildings or the like, wherein a mechanical barrier in the form of a material composition which includes a large number of thin fibres or filaments is placed in the path of the insects. The invention also relates to a barrier device. There are many instances where it is necessary to prevent the advance of insects in certain places. For instance, the attack by insects on forest plants, particularly on small and newly planted plants, can cause considerable damage and inflict considerable costs. The same is true of the insect attack on garden plants and the like. Insects can cause damage, or cause discomfort, in other contexts, for instance the migra¬ tion of ants into the home. Those insects which cause the worst damage to forestry plants and trees often move along the ground and up along the plant. Some insects only remain in the plant during certain parts of the day and must climb back¬ wards and forwards along the stem of a plant several times each day. Pine weevil, in particular, are able to cause considerable damage to conifers. It has been found, in this regard, that forest plants have a far better chance of healthy growth if they are enclosed in a mechanical insect guard subsequent to being planted. This guard iε intended to physically prevent the pine weevil from reaching the plant. Hitherto, there has been used for this purpose, among other things, a guard which iε retailed under the name Vinetta-εtocking, which haε the form of a mono-filament stocking which fully encloεeε the plant. A εimilar guard, retailed under the name PUM, compriεeε plaεtic foil which is wrapped around the plant so aε to essen¬ tially encapsulate the same. Another guard iε one retailed under the name Tenokragen which conεistε of a funnel-shaped plastic guard, which surrounds the lower part of the plant and which has a collar extending around the upper edge of the funnel-shaped part. A common purpose of all the aforesaid guards is to prevent the pine weevil from reaching the vital parts of the plant, primarily the stem, even though the pine weevil is able to climb up the guardε. The aforeεaid guards have been used to a relatively wide extent in forestry work. Experience shows, how- ever, that the cost entailed by εuch guardε iε rela¬ tively high, due mainly to the relatively laboriouε work involved in placing the guardε on the plants. Consequently, strenuous efforts have been made to devise a rational method which will enable the guardε to be applied to the plantε before the plants leave the nursery. No purposeful and succeεεful technique haε hitherto been proposed. Accordingly, the prime object of the present invention iε to provide a technique which, when neceεεary, will εtop the advance of inεectε and which can be applied rationally and at low cost and which iε to be preferred to earlier known solutionε from the aεpect of environ¬ mental care and protection. The invention is based on the discovery that insects become frightened and flee when coming into contact with thin, flexible and thread-like fibres. This may be because the insects confuse such fibres with natural cobwebs. Tests have ben carried out in this regard particularly with pine weevil, which when coming into contact with a wool-like agglomeration of loose fibres immediately turn and move in another direction, if not becoming tangled in the fibres in the process, since the fibres tend to fasten to the hairs and hooked appendices on the legs, body and antennas of the insects. Studies have also shown that, among other insects, ants, green fly, and aphides react in the same way. A method of the kind described in the first paragraph of this document is characterized, in accordance with the invention, by the use of flexible, thread-like fibres, which are laid loosely together or are joined loosely together to form manageable material composi¬ tion such that an insect which comes into contact with the material can experience the fibres as the strands of a cobweb and be repelled thereby. Thus, when wishing to protect a forestry plant, fibres are placed around the plant, or the lower part of the plant is clad with a fibre material. A ring of fibre material may be placed around the trunk of a larger tree, in order to prevent insects climbing up the tree. Correspondingly, the advance of ants can be prevented or deterred, by placing a string of fibre material across the path travelled by the ants. The invention iε thus based primarily on the deterring effect that loose fibres have been found to have on insects. From the handling aspect, among other things, it iε preferred to place-out the fibres in the form of a readily handled wool-like or felt-like composition which comprises fibres that have been loosely placed together or loosely joined together. In order to protect biological plants against attack by insects, it is preferred to wrap at least the lower part of each plant with a fibre material in the nur- sery. This can be achieved by placing the plants in a respective tube intended herefor and introducing the fibre material through the tube wall while rotating the plants relative to said tube wall. According to one preferred embodiment, there is used a flexible tube, wherein that part of the tube in which a plant is located can be imparted a rotational swinging motion which will cause the plant to rotate relative to the tube wall. In this regard, in order to enable the plant to be inserted into the tube rationally and without injury to the plant, it is preferred to draw the plant up into the tube by suction while moving the lower end of the tube in a circuit path with the centre of said path lying essentially in the centre of the plant. The fibres used must be very thin, a suitable diameter being from 1 - 100 microns and preferably from 10 - 25 microns. Other characteristic features of the present invention are set forth in the following Claims. The invention will now be described in more detail with reference to the accompanying drawings. Figures 1-3 illustrate different usages of an inventive insect guard. Figure 4 illustrates schematically a device for apply¬ ing an inventive fibre guard to forest plants. Figures 5 and 6 illustrate parts of the device shown in Figure 4, in different working stages. Figure 1 illustrates a garden plant around which a layer of fibre material 2 has been laid subsequent to planting the plant. The fibre material 2 consists of very thin, strong and thread-like fibres or filaments, for instance polypropylene fibres. Other plastics may be used, however, such as polyethylene and PVC. The fibres shall be placed loosely together or loosely joined together so as to form a manageable wool-like or felt-like composition. The fibres shall also be flex¬ ible and are suitably cut into lengths of one or two centimetres and placed in a disordered array. The thickness of the fibres may vary in dependence on the type of insect to be guarded against, although the fibres will preferably have a thickness in the order of 1 - 100 microns. Good results have been achieved with tests in which the fibres used had a thickness of from 10 - 25 microns. The tests mentioned in the aforegoing showed that an insect which comes into contact with εuch fibre mate¬ rial is deterred and turns away. This is posεibly because when coming into contact with the separate fibres, which shall not be heavily woven together, the insect feels instinctively that the fibres present a danger, for instance can be taken for the filaments of a spider's web or cobweb. The inventive fibre material has also been found to ensnare the insects coming into contact therewith, since the thin fibres hook firmly onto the hairs and hooked appendices on the bodies of the insects, therewith causing the insects to be tangled in the fibre material and unable to free themselve . Plaεtic fibre material of the kind that can be used in accordance with the present invention is very inexpen- εive, since it can consist of material used, for in- εtance, to pad cuεhions and the like or the wool-like material uεed in liquid absorbent products, such as disposable diapers or the like. The inventive material also affords the additional advantage of degrading biologically in soil more rapidly, for instance, than the earlier used plastic material, due to the small thicknesε of the individual fibres. Figure 2 illustrates the application of a ring 3 of inventive fibre material around a tree trunk 4, with the intention of preventing insects from climbing up the trunk. Figure 3 illustrates a forest plant 5 which, prior to being planted and preferably in the nursery, haε been provided with a wrapping of fibre material 6 around at least the lower part of the plant. The fibre material 6 may have a thicknesε of from 0.1 to 3 cm and will preferably extend down to and slightly beneath the level of the soil, εince some inεectε will attack the bark on the rootε of the plantε. The advantageε afforded when winding or wrapping the plant with fibre material in order to protect the plant against insect attack, particularly pine weevil attack, also include the following advantageε, in addition to the aforesaid primary advantages. Because the wool-like fibre material 6 is white in colour, the plant can be readily discerned in its surroundings. This is highly important when planting forest plants in ground which has not been prepared, since the person planting the plants must be able to see where plants have earlier been planted. Due to the reflective ability of the fibre material, the flow of light to the bark and stem of the plant is reduced. This reduces the physiological re-adaptation which the plant must normally go through after being planted, since when the plant is newly planted it is exposed suddenly to a great deal of light in an exposed place after having been stored and transported in a relatively dark environment. This sudden exposure to light can promote stress in the process of photosyn¬ thesis, this stress thus being alleviated with the aid of the fibre material. The structure of the fibre material also reduces the movements of wind around the plant, which in turn reduces the extent to which the needles of such plants dry-out and therewith reduce the water stress which normally afflicts newly planted plants. Temperature flucuations around the plant are also reduced, there¬ with protecting the plant against night frosts, which can often be a serious problem in the case of newly planted plants. The inventive fibre material can also be applied so that the top εhootε and, to some extent, alεo εide shoots on the plant can develop despite the presence of the guard. Figure 4 illustrateε a device by meanε of which the plant shown in Figure 3 haε been wrapped in or wound with inventive fibre material. The device includes a long, flexible tube 7 which, is axially movable so as to enable the tube to be lowered down over a plant 8. The plants 8 are grown very close together in some appro¬ priate type of pot or container 9 included in large plant-growing cassettes. Mounted on the upper end of the tube is a connecting line 10 which connects with a suction source, and a connecting line 19 which connects with a source of compressed air. Both connections include a throttle valve or butterfly valve 11. The reference numeral 12 identifies an excentric mecha- nism which, when the bottom end of the tube iε held εtationary, functionε to cause the centre part of the flexible tube 7 to perform a rotational, swinging movement- The reference numeral 13 identifies a schema¬ tically illustrated sensor, for instance a mechanical connection breaking device or switch, a photodetector or the like, which detects when a plant 8 passes-by. The reference numeral 14 identifies an appropriate auxiliary device for introducing a support bottom 15 into the tube 7. The tube is also provided with a εlot- like opening 16 through which wool-like fibre material can be introduced into the tube. This fibre material iε introduced into the tube with the aid of a plate-like tool or the like whoεe area is slightly smaller than the area of the slot 16. The inventive device operates in the following manner. The tube 7 iε lowered down over a plant 8 and into abutment with the upper rim of the pot 9 while opening the connection 10 to the suction source and closing the compressed-air connection, see Figure 5A. When the tube has reached the rim of the pot 9, the plant 8 and its root ball is drawn by suction up into the tube 7, Figure 5B. This is facilitated by the fact that the bottom of the pot iε perforated so that air can enter the pot. When the plant pasεeε the εensor 13, Figure 5C, the sensor sends a signal to the auxiliary device 14 which in response thereto moves the support bottom 15 into the tube and also sends a signal to a means which controls the valve 11, so aε to switch-off the suction in the tube. When the suction has been removed, the plant together with its root ball 17 will fall down onto the support bottom 15. Wool-like fibre material 18 is then fed through the slot 16 in the tube wall until contact is made with the needles on the plant and the excentric mechanism 12 is activated. As a result, that part of the tube 7 where the plant is located will be caused to execute a rotating, εwinging movement as illustrated in Figures 5D and 5E. The centrifugal force created by this movement forces the plant and its root ball 17 against the tube wall, whereupon the plant and root ball will begin to rotate as a result of a rolling movement between the plant and the tube wall. Addition¬ al fibre material iε therewith drawn in through the εlot 16 and wound around the plant. The wool-like fibre material can be taken from a carding machine, in the form of rollε of thin, non-woven layerε of fibres, the layers being mutually separated on the rolls by webs of plastic foil. Preferably, no individual fibre will have a length sufficient to encircle the plant, since fibres of such lengths would later choke the plant. When sufficient material haε been wound around the plant, for instance two turns, the excentric mechanism 12 is εtopped and the εupport bottom 15 iε withdrawn while opening the connection 10 to the compressed-air source. The plant 8 will therewith be urged down into its aεεociated pot 9, εee Figure 5F. The tube 7 iε then raiεed, to expoεe the plant around which inventive material haε been wound, Figure 5G, -and the tube -7 jLε moved to a poεition above a εubεequent plant for a repeat of the aforedescribed procedure. When the plantε are grown very cloεe together in in¬ dividual growing plant cultivating caεεetteε, and when the diameter of the green part of the plant iε allow¬ ably larger than the diameter of the upper rim of the pot and conεequently haε perhapε grown into mutually adjacent plantε, it is normally not possible to simply move the tube 7 immediately over a εelected plant, without damaging εaid plant. This problem can be εolved, however, by moving the bottom end of the tube in a circuit path with the centre of the path located εubεtantially on the centre of the plant while lowering the tube 7 down towardε the pot with the εuction-εource connection line 11 being open at the same time. This method is illustrated in Figures 6A-F. Experiments with thiε technique, utilizing both a suction effect in the tube and rotational movement of the bottom end of said tube, have shown that it iε poεεible to lower the tube over a plant which iε εub¬ εtantially wider than the inner diameter of the tube, without injuring the plant. Thiε enableε plantε to bs provided with an inventive inεect guard by meanε of a fully automatic process, already in the nursery, which provides important advantages from the cost aspect, among other things. The invention has been described in the aforegoing with reference to the exemplifying embodiment illustrated in the accompanying drawingε. It will be understood, however, that this embodiment can be varied in several respects without departing from the inventive concept and while remaining within the scope of the Claims. For instance, an inventive inεect guard can be used in other contexts; for inεtance, inventive fibre material can be placed across the path of ants or over ant- infested areas for instance, in order to prevent the ants from advancing. The method and the device by means of which a protective fibre material is placed around a plant can be varied as desired. For instance, the method used may be a fully manual method or a se i- automatic method.

Claims: CLAIMS 1. A method of preventing the advance of insectε of the kind which move on the ground on partε of biologi- cal plantε, .buildingε or the like, wherein a mechanical barrier compriεing a material compoεed of a large number of thin fibres is placed in the path of the insectε, c h a r a c t e r i z e d by uεing flexible, thread-like fibres which are placed loosely together or are loosely joined together to form a manageable mate¬ rial, such that upon coming into contact with the material an insect can experience the fibres as being the threads of a cobweb and be repelled thereby. 2. A method according to Claim 1 intended for protect¬ ing biological plants against inεect attack, c h a r ¬ a c t e r i z e d by winding said fibre material around at least the lower part of each plant. 3. A method according to Claim 2, c h a r a c ¬ t e r i z e d by introducing the plants into a tube, and by feeding the fibre material through the tube wall while rotating respective plants relative to said tube wall. 4. A method according to Claim 3, c h a r a c ¬ t e r i z e d by using a flexible tube and by causing that part of the tube in which the plant is located to perform a rotational, swinging movement thereby causing the plant to rotate relative to the tube wall. 5. A method according to Claim 3 or 4, c h a r a c ¬ t e r i z e d by drawing the plants up into the tube by suction- while moving the bottom part of the tube in a circuit path with the centre of said path lying εubεtantially on - e centre of the plant. 6. A device for preventing the advance of insects of the kind which move on the ground, on parts of biologi- cal plants, buildings or the like with the aid of a mechanical barrier which iε compoεed of a large number of thin fibreε an≤ which iε intended to be placed in the path of the insectε, c h a r a c ¬ t e r i z e d in that the material (2; 6; 18) includeε flexible, thread-like fibreε which are loosely placed together or loosely joined together to form a manage¬ able material corpcsition, εuch that when coming into contact with the barrier an insect can experience the fibreε aε being the threadε of a cobweb and be repelled thereby. 7. A device according to Claim 6, c h a r a c ¬ t e r i z e d in that the fibreε have a thickness of from 1 - 100 microns, preferably from 10 - 25 microns. 8. A device according to Claim 6 or 7, c h a r a c ¬ t e r i z e d in that the fibres are made of a biode¬ gradable material. 9. A device according to any one of Claims 6-8, c h a r a c t e r i z e d in that the fibre material (6; 18) haε a structure such aε to enable the material to be wound around a biological plant (5; 8) so aε to protect said plant against inεect attack.

Inventors: CHRISTENSEN BENT, HAGNER MATS, CHRISTENSEN, BENT, HAGNER, MATS
Applicants: CHRISTENSEN BENT, HAGNER MATS, CHRISTENSEN, BENT, HAGNER, MATS
Application year: 1991
Main classification: A01G13
IPC codes: A01G13, A01M29