Process for controlling cockroaches and other crawling insects

Process for controlling cockroaches and other crawling insects comprising deploying strips of polymeric controlled release dispensers to insect crawl paths and harborages, the dispensers containing a low volatility toxicant for the insects which is made available on the surfaces of the dispensers and which, in a concentration of from 50 to 500 mg/sq.ft. of dispenser active surface area, is lethal to the insects after relatively brief periods of direct physical contact. Generally, strips aggregating from about 1/3 to about 3 sq.ft., of active dispenser surface area are adequate to achieve control of cockroaches and other crawling insects in an average size room having a floor area of about 100-150 sq.ft.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to a process for controlling cockroaches and 
other crawling insects by the deployment, in insect crawl and harborage 
areas in residential and commercial buildings, of polymeric controlled 
release dispensers containing selected toxicants found to have unusually 
effective knockdown (KD) and kill efficacy for crawling insects based upon 
fairly short periods of contact between the insect and the dispenser. 
2. Description of the Prior Art 
Various species of crawling insects, especially the hard-to-kill cockroach, 
have been a target for eradication by man for centuries. Lately, 
pesticides have been developed which have high toxicity for cockroaches, 
but such pesticides frequently present environmental hazards when used in 
effective concentrations. The repeated application of low concentrations 
of available chemical toxicants reduces the danger to the environment but 
is also less effective and relatively more expensive. Accordingly, 
attempts have been made to develop methods and products for the controlled 
release of crawling insect toxicants over extended periods of time in a 
manner which is relatively less dangerous to man's environment and also is 
effective to protect the toxicants from premature degradation. 
According to the prior art, insect repellent fabrics in the form of tapes 
or strips have previously been provided which comprise laminated materials 
at least one layer of which contains an insecticide, alone or in 
combination with insect baits or attractants. Representative of this prior 
art are U.S. Pat. No. 2,911,756--Geary and U.S. Pat. No. 
3,295,246--Landsman et al., although the foregoing references are by no 
means exhaustive of the prior disclosures concerned with toxicant carriers 
for pest control. In the Geary patent a flexible sheet or strip is 
provided with a pressure-sensitive adhesive on one side for mounting the 
strip on a surface. The other side is provided with an insecticidal and 
insect attracting composition. An intermediate layer may be provided 
between the insecticidal composition and the substrate layer, such as 
cellulose fibers, matted, felted or otherwise joined and bonded to the 
flexible sheet. When the insecticidal insect attracting compositions are 
applied to the intermediate layer, the composition is said to be absorbed 
and kept in close contact therewith. Such devices, of which the Geary 
structure is typical, have been generally objectionable for a number of 
reasons, including (1) the external availability on the exposed surface of 
the dispenser of the main concentration of toxicant, (2) the lack of 
protection of the toxicant from atmospheric conditions which may result in 
rapid loss of efficiency, (3) the relatively low control over the rate at 
which the toxicant becomes available to the environment, and (4) the lack 
of structural protection of the toxicant layer from abrasion or other 
mechanical attrition. 
The structure disclosed in the Landsman et al patent remedies some of the 
foregoing deficiencies of Geary by providing a protective surface coating 
on the laminated insect repellent tape. The essential feature of the 
Landsman et al structure is said to be the provision of an absorbent paper 
core layer saturated with a residual insecticide. The tape is then coated 
with a light (thin) resinous solution of vinyl or polyethylene or nylon 
merely to form a surfacing without forming a substantial layer on the 
exterior face of the tape. Such structures, with their fragile outer 
facings, are subject to rupture with the possible result of rapid loss of 
the insecticide which is merely absorbed in the absorbent core layer of 
paper or other porous material and the certain result of external 
availability of the toxicant. Further, such structures would appear to 
fail to adequately protect the toxicant from degradation due to 
atmospheric exposure, and to provide minimal control over rate of release 
of the toxicant. 
The assignee of the present application has also developed a new technology 
for imparting active properties to the surfaces of solid, non-porous 
polymeric substrate materials by a technique which comprises applying to 
selected solid, non-porous polymeric substrate materials a solid, 
non-porous layer of a polymeric composition containing selected activating 
agents capable of migrating from the layer into and throughout the 
substrate. The migrating agents are incorporated in the layer in an amount 
sufficient to produce an effective level of activity on the exterior 
surface of the substrate. The application of the Herculite technology, 
known in the industry as the HERCON process, to the production of 
pesticidally active polymeric materials is generally described in U.S. 
Pat. Nos. 3,705,938, 3,857,934 and 3,864,468. Additionally, the assignee 
of this application is also the assignee of pending Application Ser. No. 
535,658 in the names of Henry Von Kohorn and myself which relates to 
pesticide dispensers also based upon the HERCON technology. 
Applicant is also aware of polymeric controlled release dispensers 
commercially available from the Shell Corporation which have generally 
been employed to control flying insects. These dispensers comprise a 
volatile toxicant known as `dichlorvos` or DDVP, which is released into 
the surrounding atmosphere and which provides a fumigant action in the 
treated space. Where the space to be treated is unventilated, satisfactory 
control of crawling insects may be achieved with such fumigant-action 
dispensers, but in well ventilated rooms this method of control is less 
effective. Due to the high volatility of DDVP the dispensers tend to lose 
their efficacy fairly rapidly and the toxicant odors are bothersome to 
many people. 
The present most widely employed approaches for the control of crawling 
insects involve the use of sprays which are environmentally or 
aesthetically generally unacceptable for residential use due to persistant 
toxicity of materials dangerous to man or animals or unpleasant 
non-toxicity effects, such as unpleasant odors, staining of surfaces, etc. 
Additionally, where non-persistent toxicants are employed in sprays, the 
effective life is short, and therefore expensive and inconvenient 
reapplications are required to achieve even a minimally acceptable level 
of control. 
Accordingly, an object of the present invention is to provide an effective 
method for controlling cockroaches and other crawling insects which 
provides prolonged residual effect, minimizes environmental hazards and 
prevents premature degradation or loss of the toxicant. 
DETAILED DESCRIPTION OF THE INVENTION 
The process of this invention comprises controlling cockroaches and other 
crawling insects in buildings by deploying in the crawl paths and 
harborages of the cockroaches and other crawling insects polymeric 
controlled release dispensers containing a non-volatile toxicant in 
sufficient amount such that the toxicant is present on the surfaces of the 
dispensers in a concentration of from about 50 to 500 mg/sq.ft., and 
preferably from about 100 to 350 mg/sq.ft. of dispenser active surface 
area. A plurality of dispensers are preferably provided which have an 
aggregate active surface area of from about 1/3 to 3 sq.ft., per average 
sized room of 100 to 150 sq.ft. The non-volatile toxicant is one capable 
of killing roaches and other insects after the insects have had direct 
contact with a dispenser for only relatively short periods of time. 
In a preferred embodiment the dispensers are provided in the form of tapes 
about 1 inch wide and 4 inches long and having a pressure-sensitive 
adhesive backing. The tapes are deployed by adhesively applying them to 
known insect crawl paths and harborages and by stuffing the tapes into 
cracks, crevices, piping holes or other apertures which provide insect 
ingress or egress. 
While any suitable polymeric controlled release dispenser may be employed, 
a preferred dispenser for use in the process is described in copending 
Application Ser. No. 603,053, filed Aug. 8, 1975 in my name. Typically, 
the dispensers comprise a layer of barrier material, such as MYLAR or 
Nylon, having a pressure-sensitive adhesive on one side. On the other 
surface of the barrier layer there is applied a polymeric layer, e.g., a 
polyvinyl chloride plastisol layer containing a non-volatile toxicant. 
Over the plastisol layer there is applied a solid, non-porous polymeric 
layer e.g., a layer of polyvinyl chloride. The toxicant is present in an 
amount sufficient to provide a surface concentration, usually of about 50 
to 500 mg./sq.ft., which has been found to achieve effective levels of 
knockdown and kill even upon brief contact with roaches or other crawling 
insects. In the preferred dispensers, the barrier layer blocks the 
progress of the toxicant towards the adhesive coated surface of the tape, 
but molecular migration allows certain toxicants to pass through the outer 
polyvinyl chloride layer and reach the exposed surface of the tape, thus 
providing an active surface. During the active life of the dispensers, the 
amount of toxicant in the body of the tape will be adequate to replace the 
toxicant depleted from the surface and maintain the surface concentration 
in the effective desired range of 50 to 500 mg. for extended periods of 
time. 
Other less effective but satisfactory controlled release dispensers for use 
in this invention comprise strips, tapes and films (or other 
configurations) of solid, polymeric materials, usually thermoplastics, 
into which effective amounts of non-volatile toxicants may be blended by 
milling or other processes and from which the toxicant will be gradually 
released over an extended period of time. 
In practicing the invention with respect to single or multi-ply polymer 
sheet applications, there may be used as the sheet of polymer, any 
polymeric material which is capable of being formed into a self-supporting 
continuous sheet or film, having adequate mechanical properties to 
withstand normal handling, abrasion, etc. The polymeric material in sheet 
form must be substantially non-porous. Suitable materials include various 
hydrocarbon polymers, such as, rubber, and olefins, for example, 
polyethylene and polypropylene, imide, amide, ester, urethane, carbonate, 
cellulosic, halocarbon, ionomer, vinyl, such as polyvinyl chloride, 
polyvinylidene chloride, polyvinyl acetate, and other polymers, and their 
blends, interpolymers and copolymers. 
Non-volatile toxicants suitable for use in the foregoing dispensers 
include, but are not limited to, chlorpyrifos, diazinon, chlordane, 
carbaryl, malathion, resmethrin, bioresmethrin, propoxur, fenchlorphos, 
2-(1,2-dioxolan-2-yl)phenyl-n-methylcarbamate, 
2-2-dimethyl-1,3-benzodioxol-4-ol methylcarbamate and Velsicol's organo 
phosphate compound Vel-4283. 
The amount of active surface area of dispensers necessary to give effective 
control may, of course, be adjusted, depending on the size of the space, 
prevailing sanitary conditions, ease of insect access, etc. 
In addition to the use of a pressure-sensitive adhesive backing, which is 
preferred, the dispensers may be deployed in accordance with the invention 
by any practical means, such as by the use of staples or tacks, by means 
of clips for pipes, ridges or other non-planar surfaces, by the use of 
separate adhesive tape materials, etc. 
The amounts of toxicant (and attractants which optionally may be employed) 
are not critical, nor is the thickness of the polymeric layer or layers, 
in the case of the preferred multi-layer dispenser. Concentrations and 
material thicknesses will ordinarily be selected to achieve certain 
objectives in terms of useful life, flexibility, and other properties such 
as color, ability to create artificial harborages, etc. 
In the case of using multi-layer dispensers, as described above, which 
include a blocking or barrier function, the barrier layers may be composed 
of polymers containing blocking plasticizers or may be formed from 
relatively migration resistant polymers, such as, polyamides and 
polyesters, e.g., Nylon and MYLAR. The latter materials are not resistant 
to migration of all active materials as has been disclosed in the issued 
Herculite patent describing the basic HERCON technology, but they are 
sufficiently resistant to the preferred toxicants identified above largely 
to control and direct migration of the toxicants through the desired 
surface layer. 
The preferred multi-layer, polymeric dispensers are tough, flexible 
laminates of integrally bonded layers and are highly resistant to 
mechanical destruction which could result in accidental and rapid loss of 
the active agent to the environment. The multi-layer polymeric controlled 
release dispensers, as well as the homogeneous extruded polymeric 
dispensers, may be used in any configuration or as part of any structural 
assembly suited to maximize efficacy against crawling insects, such as 
cockroaches. Forms such as adhesive backed sheets or strips and confetti 
are useful. The material may also be incorporated into loops, shelters, 
traps or the like. A particularly preferred embodiment of the invention 
comprises a strip of the laminated material provided with a 
pressure-sensitive adhesive coating on all or part of one surface to 
facilitate locating the dispenser in a manner to allow maximum effect 
against crawling insects, such as cockroaches. 
The preferred multi-layer polymeric dispensers for use in the process of 
this invention have the unique ability to protect active ingredients from 
degradation, thus prolonging the effective life of the insecticide without 
increase its persistence in the environment.