GB2261167A - Insect control - Google Patents

Abstract

A persistent insect barrier is produced by distributing a substance or mixture of substances, harmful to the insect throughout a three-dimensional perforate matrix which can be pumped or blown or otherwise introduced into voids or spaces actually or potentially infested by insects. The substance is e.g. bentonite. silica gel, boric acid or borax and the matrix may be made up of fibres.

Description

INSECT CONTROL This invention relates to methods of insect control, and in particular, but not exclusively, to the control of insects such as cockroaches, litter beetles and many others.

In this Specification the term "insect control substance" is used to include substances compositions or mixtures which control an insect, by killing it, deterring it or otherwise modifying the behaviour of the insect, and the term "insect control material" should be construed likewise.

Insect eradication techniques largely rely on spraying or dusting with synthetic organic insecticides. However, the use of these presents several problems; their toxicity to man, the difficulty in reaching insects that have sought refuge in generally inaccessible places such as wall cavities, voids, ducts, crevices etc., and the relatively short period for which they remain toxic to insects. For these reasons, there is a considerable need for insecticides which are non-toxic to man, persistent, and which can be incorporated into building structures such as cavities, voids etc.

Many years ago, before the widespread adoption of powerful organic insecticides, it was proposed to use socalled "sorptive" dusts to cause the death of certain species of insect by drawing out the wax from the insect's back (the cuticle) whereafter the insect can no longer retain body moisture and so it literally "dries" to death.

Interest in such materials tended to tail off with the discovery of the organic insecticides. Furthermore, sorptive dusts were difficult to apply in an effective way.

Using the usual method of dusting onto a surface it was difficult to ensure complete coverage, particularly where there were winds or air movements which might later blow away the dust, or where the interior of, say, a timber-frame wall needed to be treated where access is 'blind'.

Also, research has shown that insects will take great care to avoid traversing a treated area, or will make tracks across areas where the dust is very thinly coated, thereby avoiding contact with the cuticle.

We have found a way in which substances noxious to insects can be introduced into areas of limited access to provide a three-dimensional persistent distribution of the noxious substance, thus greatly enhancing the efficiency thereof.

Accordingly, in one aspect this invention provides an insect control material comprising a distribution of an insect control substance in a three dimensional perforate matrix.

The insect control material may be used to fill a hidden space, such as by injection of the material into a hollow partition wall. A complete fill is preferred to ensure that the space is filled in three dimensions with the insect control material. This makes it extremely difficult, if not impossible, for the insect to traverse or live in the space without making intimate and severely damaging, if not fatal, contact with the sorptive substance.

The insect control substance preferably comprises a sorptive or oleophilic substance. Sorptive dusts are suitable for this purpose, for example bentonite and silica gel, although there are many others which are oleophilic and hence effective in this respect. Many sorptive or olephilic powders have the great advantage of being non-hazardous and non-toxic to humans and animals, thus eliminating some of the undesirable side effects of many organic insecticides.

They are also chemically stable and may remain effective for an indefinite period. Other sorptive dusts include aerogels, activated carbon, Fuller's earth (including olancha clay, and attapulgite clay), pyrophyllite, barytes, molecular sieves, carborundum and montmorillonite.

Furthermore, the insect control substance may be or include one or more boron compounds, for example borax or boric acid which are believed to be poisonous to the insects and are ingested by the insect when cleaning itself.

The three-dimensional perforate matrix may be in many different forms; it may be a collection of elements together making up a matrix or it may be a single integral matrix.

In either case the matrix serves to distribute the insect control material over a large volume, preferably defining narrow passages through which the insect cannot pass without making contact with the insect control substance.

The matrix may comprise a matrix of fibres. A suitable matrix of cellulose fibre may be made from milled paper which is capable of carrying the coating of insecticidal or insect-deterrent substance or composition in sufficient concentration without allowing it to settle out. However, any fibrous medium may be used such as mineral wool, organic fibres, synthetic textile fibres, and other naturally occurring fibres such as cotton, jute or sheepswool.

Other forms of non-fibrous matrix may be suitable, provided that they can hold the insecticidal or insectdeterrent substance or composition in a dispersion and provide passageways which the insect may use and in the process of which will make contact with dust.

Furthermore, sorptive substances or dusts could be used in products not intended to contain pathways but into which the insect may tunnel. In this way the sorptive dust may be used not primarily to eradicate insect infestation but rather to provide preventative protection from damage by insects.

In another aspect, this invention provides a method of eradicating insects in a space or volume, or rendering a space or volume resistant to insects, which method comprises at least partially filling said space or volume with a three-dimensional perforate matrix incorporating therein an insect control material as herein before defined.

In this aspect, an insecticidal or insect resistant barrier may be provided around an item to be protected.

In a further aspect, this invention extends to a method of rendering a three-dimensional perforate material resistant to penetration by insects, which method comprises introducing into said perforate material an oleophilic substance.

This invention also extends to any inventive combination of features set out above or in the following example.

Example Recycled paper was fibrised by shredding it and then passing it through a series of hammermills so that the fibrisation occurred in stages. At the final hammermill boric acid borax and silica gel were accurately metered in so that the final composition consisted of cellulose fibres typically of density;20-60kg/m3, with the additive materials finely distributed in powder form through the fibres in the following proportions: Fibre 66-85% Boric Acid 8-16% Borax 5-10% Silica Gel 2-8% The fibrous material so produced on exit from the mill was weighed, packed into bags for storage, transport and use. The material was found to have significant lethal and deterrent effects on cockroaches. Furthermore, it was found also to reduce the mobility of such insects. Thus, in addition to killing the insects it also exhibited a valuable effect in modifying the behaviour patterns of the insect, thus providing a management strategy for their control.

A significant advantage of the material is the ease with which it may be introduced into voids and spaces with only very limited access, using a blowing technique. In this technique the material is fed into a machine which has agitator blades which break up or separate the fibres which are then blown along a delivery tube.

Claims (17)

1. An insect control material comprising a distribution of an insect control substance in a three-dimensional perforate matrix.

2. An insect control material, according to Claim 1, wherein said insect control substance comprises a sorptive or absorbent substance which draws out wax or oil from the insect on contact therewith.

3. An insect control material according to Claim 2, wherein said sorptive substance comprises bentonite, or silica gel.

4. An insect control material according to any preceding claim wherein said insect control substance comprises a substance toxic to the insect.

5. An insect control material according to Claim 4, wherein the toxic substance comprises a boron compound selected from boric acid and borax.

6. An insect control material according to any preceding claim, wherein the three-dimensional matrix is a collection or agglomeration of elements together making up a matrix.

7. An insect control material according to Claim 6, wherein said matrix is made up of fibres.

8. An insect control material according to Claim 7, wherein the fibres are cellulose fibres.

9. An insect control material according to Claim 8, wherein said fibres are obtained by recycling paper.

10. An insect control material according to Claim 7, wherein the fibres are mineral or organic fibres.

11. An insect control material according to Claim 7, wherein the fibres are synthetic textile fibres.

12. An insect control material according to Claim 7, wherein the fibres are of animal or vegetable origin.

13. An insect control material according to Claim 6, or any claim dependent thereon, comprising by weight 0%-20% sorptive material, 0%-40% boron compounds, at least one of said sorptive material and said boron compounds being present, with the balance being made up of fibrous material.

14. A method of controlling insects in a space or volume, which method comprises at least partially filling said space or volume with an insect control material according to any of the preceding Claims.

15. A method according to Claim 14, wherein said insect control is introduced into said space or volume by entraining said material in a stream of air and directing said stream of air and entrained material into said space or volume.

16. An insect control material substantially as hereinbefore described with reference to the Example.

17. A method of controlling insects, substantially as hereinbefore described with reference to the Example.