GB2168680A

GB2168680A - Distribution of living arthropods or the like

Info

Publication number: GB2168680A
Application number: GB08432375A
Authority: GB
Inventors: Stephen Eric Bunting; Benjamin John Bunting
Original assignee: BUNTING PEGGY CATHERINE; BUNTING PETER ERIC
Current assignee: BUNTING PEGGY CATHERINE; BUNTING PETER ERIC
Priority date: 1984-12-21
Filing date: 1984-12-21
Publication date: 1986-06-25
Also published as: GB2168680B; NL8503528A; GB8432375D0

Abstract

Living arthropods (or similar predators) are inserted in an envelope 10 of a micro-perforated plastics material along with sufficient food material to enable the arthropods to be sustained. The margins 12 of the envelope 10 are sealed together, to contain the arthropods within the envelope, the sealed margins 12 defining a central hole 13, a cut 14 extending to the hole and a diagonal corner cut 16. The arthropods are distributed at a site of infestation to be controlled thereby, by tearing off the corner portion of the envelope adjacent cut 16, so distorting the envelope material and preventing the open corner region self-closing, and then hanging the envelope on a plant stalk or branch, by means of hole 13. <IMAGE>

Description

SPECIFICATION Distribution of living arthropods or the like This invention relates to a method and means for the distribution of living arthropods or the like, such as small living predators and parasites.

In order to ensure high produce yields from various kinds of plants, it is most important to ensure that infestations of pests which are liable to damage the plant or produce are controlled, if not altogether eliminated. For many years, use has been made of synthetic pesticides which may be fairly specific, or which may be lethal to a very wide range of pests such as insects, mites and nematodes. However, the use of such pesticides must be undertaken with great care, since they may be environmentally damaging and lethal to harmless animals. Also, they may taint the produce or reduce the yield, and more importantly one must ensure that there is no risk of consumers being poisoned by the toxins in the pesticides, especially when the pesticide is used shortly before harvesting.

Particularly in the case of closed, controlled environments, such as are to be found in glasshouses, there has been a tendency in recent years to move away from synthetic pesticides for controlling crop-damaging pests, towards "natural" biological control methods, using predatory or parasitic arthropods or the like (hereinafter referred to as "predators or parasites") which are harmless to the plants and produce but which attack the infestation by pests. For example, a Trialeurodes vaporariorum (whitefly) infestation may be controlled or substantially eliminated using the parasitic wasp Encarsia formosa. Also, considerable use is now being made of Phytoseiulus persimilis to control infestations of Tetranychus urticae (glasshouse red spider mite).Biological control methods also have the advantage that they can be used to control pests which have developed resistance to synthetic pesticides.

In general, a grower cannot with ease himself rear the predators or parasites to control infestations of pests: rearing such control agents requires specialised skills. It is usual for a grower to purchase the predators or parasites developed to some particular stage and then to distribute them around the infested area. However, as will readily be appreciated, the transport and uniform distribution of predators or parasites is most difficult successfully to accomplish. Some insects-such as the parasitic wasp Encarsia formosa-with convenience can be distributed whilst in the pupal stage of their life cycles, and various techniques are being used to enable the distribution of such pupae.Other arthropods such as Phytoseiulus persimilis, in general have to be transported and distributed in an active and mobile state and this requirement has proved to be difficult successfully to achieve. Originally, the leaves of a plant infested with the living mites were harvested, placed en masse in a suitable container and sent to a grower whilst being kept as cool as possible to reduce the rate of leaf deterioration and to reduce the mite activity. The grower then distributed the leaves on the plants infested with pests, but any given leaf might well have been free of mites. Also the leaves could transfer disease infections to the plants, and the site of introduction of the mites could not easily be discerned.

As a result, more recently the living mites have been placed in a mass of lightweight granular material (such as sawdust or bran) within a vessel closed except for an air-permeable or porous membrane. On receipt of the vessel, the grower opens it and sprinkles the contents over the infested plants. Such a distribution method is not particularly satisfactory, in that the mixture of the living mites and light granular material is unlikely to be uniform within the vessel and so on sprinkling the mixture around plants, some may have an excess of mites in their immediate vicinity, whereas others may have virtually none. In addition, experience has shown that materials such as sawdust or bran tend to have an abrasive effect on the mites and can cause considerable damage thereto. Also, the shelf life of such a mixture is relatively short.

It is a principal object of this invention to provided a method and means for distributing living predators and parasites, which at least mitigate some or all of the various disadvantages outlined above of the currently-used systems.

According to one aspect of this invention, there is therefore provided a method of distributing living arthropods or the like, in which a quantity of the living arthropods or the like are inserted along with at least material suitable for the arthropods or the like to continue their life cycle in an envelope formed vfrom an airpermeable material, the envelope also having two sealable margins around the envelope opening which margins when sealed together define a hole lying wholly within the extent of the margins and also a cut lying within the margins and leading from an adjacent edge of the envelope to a side portion of the hole, whereafter the two margins of the envelope are sealed together so containing the arthropods or the like but permitting them to continue their life cycle, and then when the arthropods or the like are to be released the envelope is opened and is hung from a suitable stalk, branch or the like by passing the stalk, branch or the like along the cut to enter the hole in the sealed margins.

It will be appreciated that in the distribution method of this invention, the living arthropods or the like are given a closed environment in which to continue their life cycle until such time as they are to be used to control an infestation. Then, a grower may release the arthropods or the like very close to the site of infestation, knowing that infested plants will receive an appropriate number of the arthropods or the like. Thus, infestations may more surely and reliably be controlled with the method of this invention, with little probability of any disease infection transfer to the plants.

Also a grower may easily see where distribution has taken place. A further advantage is that the envelope affords an environment protecting the arthropods or the like against spraying of water or chemicals for the initial period following opening of the envelopes and the distribution thereof on plants.

Opening of the envelope is advantageously performed merely by tearing a corner portion of the envelope in the region of the sealed margins. Using an envelope for example of polyethylene, it has been found that tearing of the envelope in this way stretches and otherwise distorts the plastics material in the region of the tear, so preventing the torn edges moving close together after tearing and thus ensuring that there is a sufficient aperture through which the living and active arthropods or the like may leave the envelope.

The material inserted in the envelope, in order to be suitable for the arthropods or the like to continue their life cycle, such serve as or carry food for the arthropods or the like.

For instance, in the case of Phytoseiulus persimilis, the inserted material may be a bean leaf carrying red spider mites.

According to a second aspect of this invention, there is provided an envelope for the transport and distribution of living arthropods or the like, which envelope is formed from an air-permeable material, the two major areas of the envelope around the opening each defining a margin which may be sealed to the other margin to enclose the envelope contents, the margins when sealed together defining a hole lying wholly within the extent of the sealed margins and also defining a cut leading from the adjacent edge of the envelope into the hole.

As discussed above, the envelope of this invention may be used for the distribution of living arthropods or the like by inserting into the envelope at least a piece of some material suitable for the arthropods or the like to continue their life cycle as well as the living arthropods or the like, whereafter the two margins of the envelope are sealed together to form a closed environment in which the living arthropods or the like may continue their life cycle.

The envelope may be made of materials such as plastics (for example polyethylene or polypropylene) or paper. In the case of materials which do not exhibit significant air permeability, such as plastics materials, the materials may be micro-perforated. Also, when organic material such as pieces of leaf are inserted along with the living arthropods or the like, it may be advantageous to ensure the envelope material also is water vapour permeable.

The envelope material preferably is inherently suitable for, or has been treated to render it suitable for, heat sealing so that the margins may be sealed together by a heatsealing technique. However, for certain materials. It may be preferable to use an adhesive to effect the seal between the two margins.

The margins, when sealed, advantageously define a perforated line or further cut, extending across a corner region of the margin, from the top thereof towards but stopping short of the major envelope area contiguous with the margins. This perforated line or further cut preferably extends diagonally across a corner region of the envelope. Then, on order to open the envelope, the envelope margins to each side of the perforated line or further cut may be firmly gripped and pulled apart, so tearing away a corner area of the mjor envelope areas and thus opening the envelope.

This tearing action will distort the envelope so ensuring that when torn there is a clear aperture through which living arthropods or the like contained within the envelope may leave.

Preferably, the margins of the envelope are sufficiently broad to permit the gripping thereof between a thumb and forefinger. In this way, the margins only may be gripped by the fingers of two hands when the envelope is to be opened and consequently the risk of damage to the living arthropod or the like within the envelope, by crushing between the major areas thereof, is virtually eliminated.

The hole through the top margin preferably is centrally positioned, but may be off-centre, for example to coincide with a seam in the envelope, so as to impart greater strength to the margin in the region of the hole. For a case where the envelope material is relatively strong, the cut leading to the hole may extend perpendicularly to the adjacent envelope edge into the top of the hole, but preferably the cut extends at an acute angle to the adjacent envelope edge to a point on the hole on the side or lower part thereof. In this way, the envelope will not readily be dislodged once positioned on a leaf stalk or branch.

The hole through the top margin as well as the two cuts (or one cut and perforated line) in that margin may be formed either before the two margins are sealed together, during the sealing operation, or after sealing, whichever is more convenient for the manufacturing process. For example, in the case of a heat sealing operation, it may be advantageous to provide a heat sealing machine with appropriate tools in the plattens thereof, such that as the heat sealing is effected the tools cut the envelope material to provide the through hole and two cuts.

By way of example only, one specific embodiment of envelope arranged in accordance with this invention and intended for the distribution of Phytoseiulus persimilis will now be described with reference to the accompanying drawing, which is a perspective view of such an envelope ready to contain living Phytoseleius persimilis mites.

The envelope 10 illustrated in the drawing is manufactured from so-called medical grade 60 gm paper so as to have overall dimensions of approximately 100 mmX120 mm. Such medical grade paper is permeable both to air and water vapour, and has a heat-sealing lacquer applied on one face (the internal face for the case of the envelope) in a grid pattern.

Each side sheet 11 of the envelope adjacent one end thereof (the open end of the envelope, before sealing) defines a margin 12 which is sealed to the opposed margin, by a heat sealing technique. Wholly within the confines of each margin but centrally thereof is a through-hole 13, and a cut 14 leads from top edge 15 of the envelope to a side of that through-hole, this cut thus extending at an acute angle to the top edge of the envelope.

There is moreover a further cut 16 in each margin, these cuts 16 extending in a corner region of the envelope and again extending at an acute angle to the top edge. These further cuts 16 stop short of the lower edges of the margins 12 and so do not interfere with the sealing of the envelope.

To use the envelope, a leaf-for example of dwarf french bean infested with red spider mites-and carrying perhaps 25 Phytoseleius persimilis mites is inserted in the envelope and the two margins 12 are heat-sealed together. In this closed environment, the mites may live for perhaps 28 days, depending upon the ambient temperature, and humidity as well as a continuance of the red spider mite food supply. Many such envelopes may be arranged side by side in a box, so permitting easy transport of a relatively large number of envelopes each containing living mites.

When the mites are to be distributed around an infested growing area, the grower decides on or is advised of the appropriate number of mites to be distributed on any given plant or area, depending upon the state of infestation, and then tears open the appropriate number of envelopes, hanging each envelope for example on the leaf stalks of the infested plants. Each envelope is opened by grasping the margins 12 to each side of the further cut 16 with the thumb and forefinger of both hands, and then sharply tearing off the corner of the envelope. This distorts the envelope material in the region of the torn corner, so ensuring that a clear opening is left for the mites to leave the envelope. Then, the envelope is hung on a leaf stalk by passing the stalk along the cut until the stalk is located within the hole, whereupon the envelope is released to hang.

Claims

1. A method of distributing living arthropods or the like, in which method a quantity of the living arthropods or the like are inserted along with at least some material suitable for the arthropods or the like to continue their life cycle in an envelope formed from an air-permeable material, the envelope also having two sealable margins around the envelope opening which margins when sealed together define a hole lying wholly within the extent of the margins and also a cut lying within the margins and leading from an adjacent edge of the envelope to a side portion of the hole, whereafter the two margins of the envelope are sealed together so containing the arthropods or the like but permitting them to continue their life cycle, and then when the arthropods or the like are to be released the envelope is opened and is hung from a suitable stalk, branch or the like by passing the stalk, branch or the like along the cut to enter the hole in the sealed margins.

2. A method according to claim 1, in which opening of the envelope is performed by tearing a corner portion of the envelope in the region of the sealed margins in such manner that the tearing stretches and otherwise distorts the material of the envelope in the region of the tear, so ensuring that there is a sufficient aperture through which the living and active arthropods or the like may leave the envelope.

3. A method according to claim 1 or claim 2, in which the material inserted in the envelope serves as or carries food for the arthropods or the like.

4. A method of distributing living arthropods or the like substantially as hereinbefore described with reference ti the accompanying drawings.

5. An envelope for the transport and distribution of living arthropods or the like, which envelope is formed from an air-permeable material, the two major areas of the envelope around the envelope opening each defining a margin which may be sealed to the other margin to enclose the envelope contents, the margins when sealed together defining a hole lying wholly within the extent of the sealed margins and also defining a cut leading from the adjacent edge of the envelope into the hole.

6. An envelope according to claim 5, wherein the envelope is made of a micro-perforated plastics material or a paper material rendered substantially water-impermeable, but water-vapour permeable.

7. An envelope according to claim 5 or claim 6, wherein the material from which the envelope is made is inherently suitable for, or has been treated to render it suitable for, heat sealing whereby the margins may be sealed together by a heat-sealing process.

8. An envelope according to claim 5 or claim 6, wherein an adhesive coating is provided on at least one of the margins to permit adhesive bonding between the two margins.

9. An envelope according to any of claims 5 to 8, wherein the margins, when sealed, define a perforated line or further cut extending across a corner region of the sealed margins, from the top edge thereof towards but stopping short of the major envelope area contiguous with the margins.

10. An envelope according to any of claims 5 to 9, wherein the margins of the envelope are sufficiently broad to permit the gripping thereof between a thumb and forefinger.

11. An envelope according to any of claims 5 to 10, wherein the hole through the sealed margins is centrally positioned in the margins.

12. An envelope according to claim 11, wherein said cut extends at an acute angle to the adjacent envelope edge to a point on the hole on the side or lower part thereof nearer the major areas of the envelope.

13. An envelope according to claim 5 and substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.