CA1041950A - Dispenser for cockroach control - Google Patents

Abstract

ABSTRACT
Dispensers and methods are described for the control of insects, especially cockroaches, with prolonged residual effect, and the protection of the toxicants employed from deg-radation due to exposure to atmospheric conditions. The dis-pensers are specially constructed laminates of layers of solid polymeric materials , and may be provided in the form of ad-hesive strips, loops, shelters (harborage), traps, confetti or other suitable configurations. The laminates have a core layer preferably formed from a plastisol of a polymer, con-taining specially selected active agents from the group con-sisting of Chlorpyrifos*, Diazinon*, Chlordane*, Carbaryl*, Mala-thion*, Bioresmethrin*, and Fenchlorphos* which have been found to be active agents which not only are toxic to cockroaches but also are capable of migrating from the core layer to provide effective levels of toxicant on the surface of the dispenser and to control the release of additional toxicant to maintain a prolonged residual effect with minimum danger to the environment.

Description

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The present invention relates to dispensers for the control of insects, especially cockroaches, over extended pe-riods of time in a manner which allows a reduction in the concentration of toxicants in the atmosphere and also protects the toxicants from premature degradati~n due to exposure to atmospheric conditions.
Various species of insects, and especially cock-roaches, have been a target for eradication by man for centu-ries. Lately, pesticides have been developed which have high toxicity for cockroaches, but present environmental hazards when used in effective concentrations. Repeated low concen-tration application 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 systems, methods and products for the control-led release of cockroach 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 degradatibn.
According to the prior art, insect repellent tapes or strips have been provided comprising laminated materials at least one layer of which comp~ises an insecticide, alone or in combination with insect bait or attractants. Representative of this prior art are U. S. Patent 2,911,756 Geary and U. S.
Patent 3,295,246 Landsman et al, although the foregoing re-ferences 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 ;.~ . .. ., -;: - . . :

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and insect attracting composition. An intermediate layer may be provided between the insecticidal composition and the sub-strate layer, such as cellulose fibers, matted, felted or otherwise joined and bonded to the flexible sheet. When the insecticidal, insect attracting composition is applied over such an intermediate layer it is said that the composition is 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 the availabil-ity on the exposed surface of the main concentration of toxi-cant, lack of protection of the toxicant from atmospheric con-ditions which may result in rapid loss of efficiency, rela-tively low control over the rate at which the toxicant be-comes available to the environment, and lac~ of structural protection of the toxicant layer from abrasion or other mechan-ical attrition. ;
The structure disclosed in the Landsman et al patent remedies some of the foregoing deficiencies of Geary, by pro-viding 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 absorbent paper saturated with a residual insecticide. The tape is then coated with a light resinous solution of vinyl or polyethylene or nylon merely to form a surfacing t~ithout forming a sub :antial coating layer on the top face of the tape and absorbent mate-rial. Such structures, with their fra~ile outer facings, are subject to rupture with resultant rapid evaporation, volatil-ization and loss of the insecticide which is merely absorbed in the absorbent core layer of paper or other porous material.
I am also aware that the assi~nee of the present . . .
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applica.ion, llerculite Protecti~e Fabrics Corporation, has pioneered a new technology for impartiny active pro?erties to the surfaces of solid, non-porous ?olymeric substrate mate-rials by a technique ~7hich comprises appl,~ing to selected solid, non-porous polymeric substrate materials a solid, non-porous laier of a polymeric composition containing selected activatins agents capable of migrating from the layer into and throu~hout the substrate. The migrating agent is incor-porated 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,'kno~n in the industry as the HERCON process, to the production of pesticidally active polymeric materials is generallv described in U. S. Patent 3,705,938 issued December 12, 1972, and in U.S. Patent Nos. 3,857,934 and 3,864,468, which are divisional cases related to the just mentioned issued patent. Additionally, Herculite is the assignee of Canadian pending a~plication Serial No. 181,524 in the names of Henry von Kohorn and myself which relates to pesticide dispensers also ~asec upon the HERCON technology.
Accordingly, an object of the present invention is to provide dispensers, particularly effective against cock-roaches, ~-hich have prolonged residual effect, minimize envi-ronmental hazard, and prevent premature degradation or loss of the coc~roach toxicant.
The present invention relates to specific s~stems for controlling insects, and especially cra~ling insects such as the coc~roacll target species, in a particularly effective manner, es?ecially in terms of prolonged effect ~ith minimum hazard to the humall environment.
*Trade Mark In accordance with the present invention dispensers ef-fective in the control of cockroaches and other insects are pro-vided which comprise laminated articles having a first outer layer of a polymer selected from the group consisting of polyethylene, polypropylene or polyvinylchloride, a second interior or core layer comprising a polymer selected from the group consisting of poly-ethylene, polypropylene or polyvinylchloride. The core layer is preferably formed by being deposited from a plastisol composition.
The plastisol used to form the core layer comprises the polymer, a plasticizer for the polymer, and a cockroach toxicant selected from the group consisting of Chlorpyrifos*, Diazinon*, Chlordane*, Carbaryl*, Malathion*, Bioresmethrin*, Fenchlorphos* and Propoxur*
and mixtures thereof, which agent is capable of migrating from the core layer through the first layer to provide an effective amount of the toxicant on the exterior surface of the dispenser.
The toxicants must be employed in an amount of at least about 10~ by weight of the total weight of the laminate. The laminate further comprises one or more additional layers which sandwich the intermediate toxic~ntcontaining layer in the core of the laminate. The other layers may also permit migration of the toxicant to the exterior surface to provide additional surface area on which there is present an amount of toxicant effective --against cockroaches.
Preferably the applicant's dispenser comprises a co-extensive four-layered solid non-porous strip formed from the lamination of layers comprising, an outer layer, exposed on a first surface to the atmosphere, of a solid sheet of polyvinyl chloride through which the insecticidal agent is capable of migrat-ing by molecular migration to become available at the first sur-face; laminated at the second surface to at least one core layerof a solid non-porous layer of a solidified polyvinyl chloride plastisol containing an essentially non-volatile, contact-effective anti-cockroach agent selected ~om the group consisting of Chlor-*Trade Mark - see page 22 5 ~. . ~

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pyrifos*, Diazinon*, Chlordane*, Carbaryl*, Malathion*, Bioresmeth-rin*, Fenchlorphos*, Propoxur*, and mixtures thereof in an amount of at least 10~ by weight of the total weight of the laminate;
attached at the side opposite the outer layer to a solid sheet of a polymeric material which is a barrier to the molecular migration of the agent, attached at the side opposite the core layer to a layer of a pressure-sensitive adhesive to permit mounting of the strip on a surface compatible with the adhesive, the first surface of the outer layer being supplied continually with an effective level of agent from the core for a period of at least about 4 months from the time of deployment in the atmosphere.
In order to achieve a desired level of structural integrity, satisfactory migration, and still retain flexibility, the outer layer of the polymer through which the active agent migrates should preferably have a thickness on the order of from about 1 to about 10 mils, the polymeric core layer containing the active agent should preferably have a thickness on the order of *Trade Mark - see page 22 ` -5a-10~1950 from about 2 to about 20 mils, and the o~erall laminate should preferably have a total thickness of up to about 30 mils. It should be understood that thQ polymers and thicknesses may be selected so that a relatively stiff strip is obtained which is capable of being forced into cracks and crevices to reach areas in which insects would ordinarily be protected.
Where the other layer or layers do not permit mi-gration, but provide a bloc~in~ or barrier function, they ma~
be composed of polymers containing bloc~ing plasticizers or relatively migration resistant polymers, such as polyamides ' an~ polyesters, e.g., nylon and MY~R ~ The latter materials are not resistant to migration of all active materials as has been disclosed in the issued Herculite patent describing the basic HERCO~ technology, but they are sufficiently resistant to the present active agents largely to control and direct migration of the cockroach toxicants through the desired sur-- face layer.
The resulting dispensers are tough, flexible lami-nates of integrally bonded layers and are highly resistant to mechanical destruction which could result in accidental and rapid loss of the active a~ent to the en~ironmen_, The l~.mi-nate may be used in any configuration or as part of any struc-tural assembl~y suited to ma~imize efficacy against cocXroaches.
Forms such as adhesive bac~ed sheets of strips, and confetti are useful. The laminate may also be incorporated into loops, shelters, traps or the like. A particularly preferred embodi-ment of the invention ~omprises a strip of the laminated mate-rial provided ~ith a pressure-sensitive adhesi~e coatin~ on all ~r part of one surf~ce to facilitate locating the dis-penser in a manner to allow maximum effect n~ainst roaches.

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The stri2s ma~ also be formed of dark, light absor~ing, non-reflective materials, particularly attrac~ive to roaches and other insects ..hen depl.oyed as harborages.
More specific aspects of the invention will be appreciated in vie~ of the following specific Examples.
Example 1 A sheet of polyvinylchloride film having a thick-ness of .004 inch was coated with a plastisol coating pre-pared by dispersing 100 parts of polyvinylchloride resin in about 25 parts of dioctylphthalate and then dispersing 120 parts of Chlorp~rifos into the 125 parts of plastisol. The - plastisol thus prepared was mixed until uniform and the - coating was applied to the base sheet of polyvinylchloride in a thickness of about 0.02 inches. The coated polyvinyl-chloride film was then overlaid with a second sheet of poly-vinylchloride also having a thickness of 0.004 inches. The assembled layers ~ere then laminated under suitable conditions of heat and pressure until an integral firmly bonded product was obtained. ~he laminated structure thus produced contained approximately 30.8~ chlorpyrifos insecticide based on the total weight of the laminate.
.- Examples 2 - 8 Additional dispensers were prepared in accordance with the procedure described in Example 1 but replacing the active asent as follows:
Example 2 - ~lalathion - 5 Example 3 - ~lalathion - 33.7~
Examplc 4 - Chlorp~rifos - 5%
Example 5 - Chlordanc -. 5Q
E~ample 6 - Chlordane - 20.7 *~rade M~rk 10419S~

Example 7 - Diazinon - 21.2%
Example 8 - Carbaryl - 22.7g The t~sting was performed by the methods developed by J. M. Grayson and H. G. Townsend and described in Pest Co~trol, 30(6), page 14 (1962) and by J. M. Grayson in Pest Control, February (1970). l~o tempered masonite panels, held apart by staples, were placed in the bottom of a one gallon glass jar to provide a hiding place for the insects.
The polymeric dispenser was placed on the top of the bottom panel. A sample of 30 female cockroaches was placed in each jar and observations on mortality were then made. In the case of the low concentration (5%) dispensers, the mortality ~ ~ -(dead and moribund) was observed after six days; in the case of the high concentration dispensers, mortality was observed at the end or one day, three days and six days. The test with the high concentration dispensers was also repeated after 60 days and 150 days after the date of preparation of the dispensers. The results of this testing are shown in Table 1.

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~ 041950 After t~Yo days of aging and si~ days of e~posure to the di,penser, Diazinon killed all of the female German cockrozches in both strains. Malathior. also was effective in killing cockroaches in a normal strain, but not in the diazino-.-resistant strain. Chlorpyrifos ~7as the most effec-tive of the treatments, as it gave complete kill of cock-roaches in both strains at the end of one day of ex~osure.
Chlordan- was reasonably effective against the nor~al strain, but onl~ moderately effective against the diazinon-resistant ; lO strain. Carbaryl exhibited little activity against cocX-roaches in either strain.
The dispensers were then aged and retested. The results, as seen in Table l, after sixty (60) and one hun-dred and fifty (150) days of aging are generally better than those obtained after two (2) days of aging. This may be explained by the fact that it takes a period of time, some-times se~eral days or more, depending on the toxicant, and polymer la~inate system for the toxicant to migrate and allow th- dispenser to ~ecome fully functional. Thus, Dia-zinon, cilorpyrifos and chlordane gave complete kill of nor-mal and Diazinon-resistant coc~roaches after six days of ex-posure ~o the dispensers which had been aged for 60 days.
~lalathion gave co~plete kill of normal strain and better kill of diazinon-resistant cockroaches than was the case in the first test. Carbar~1 gave the poorest results ~n the dia-zinon-resistant strain, but produced comple~e ~ill of thc normal cockroaches after six days of exposure. The results after 150 days of aging do not show any signs of diminishing effectiveness.
Grayson, in his continuous study (Pest Control, ' , *Trade Mark ~-t - lO -~041950 February, 7 972) to find chemicals that will be effective as residual applications against resistant and susceptiblo strains of German roaches used chlorpyrifos, Diazinon, Chlor-dane and Malathion oil sprays as controls in his experiments.
The test method used was the same as described above and the deposit of insecticide on the masonite panels was approxi-mately 150 mg/ft.2 The results obtained by Grayson are shown in Ta~le 2. A comparison of the data in Tables l and 2 sho:s that present dispensers give superior results, especially after two months of aging.
Table 2 Percentage Mortalities at the end of one, three and six days Y following exposure of female German cockroaches to panels which had been treated with different insecticides and the deposits allowed to age for various periods of time.
(Testing done at Blacksburg, Virginia, 1971)

2/ Cockroach Age of Insecticide Deposits(Days) Insecticide- Strain3/ 2 Days 60 Da~s Malathion 3.0% diazinon-R48 92 100 4 18 56 oil-bzse Normal 97 99 100 44 90 99 Chlorpyrifos 0.5~ diazinon-R56 100 100 0 8 46 oil-base Normal99 100 100 59 97 99 Chlordane 3.0% diazinon-R52 74 92 14 56 82 - oil-b~se Normal100 100 100 29 100 100 Diazinon 1.0~ diazinon-R82 100 100 4 16 34 oil-base Normal100 100 100 82 100 100 :. ~ .
1/ Under each column the first figure is the percentage ~ortalit~ at the end of a l-day exposure period, the second is for a 3-da~ exposure period, and the third fiqure is for a 6-day exposure period.
2/ All m~terials were appli~d on a weiqht/volume basis. The ~ ~eposit of insecticide was approximately 150 mg~sq.ft. from 1.0~ formulations.

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3/ Tests with normal strain were reDlicated 4 times. ~upli-cate test~ were made -~tith strains resistant to Diazinon or Malathion, making a total of 4 replicates with resistant strains.
Exam~le 9 - A synthetic pyrethroid (d-trans resmethrin, also known as Bioresmethrin ~as incor~orated into a dispenser ; constructed in accordance with Example 1 at a concentrationof 12.5~ of the total weight and the dispenser was evaluated in sheet as well as 1/8" confetti form in tests against adult, male German cockroaches. Squares of active sheet dispenser were sealed to the upper surfaces of 3" x 3" glass plates, with opa~ue plates mounted 3/16" above these surfaces to give the insects a hiding place. These assemblies were then placed in containers with 20-100 adult, male German cock-roaches and ~noc~down and kill counts were made as shown in Table 3. The insects and the opaque covers were removed after 48 hours so the active dispenser was fully exposed to . . .
ambient laboratory lights (65 fc), temperature (80F), and humidity (50% ~) until the next test period. The dispenser was compared with the untreated PVC control and with filter paper surfaces treated with 3ioresmethrin (12.5~ of total wt.). The "confetti" form dispenser (2542 mg) was compared with an equal weight of No. 1 t~hatman filter paper containing 12.5% pyrethroid by continuous exposure of adult, German cockroaches to the treated materials in large crystallizing dishes.
The shect dispenser containing synthetic pyrethroid continued to show good kllockdown and kill of the insects after 34 da~-s in th~ laboratory, ~hile the trcated filter pap~r rapidl~ decreased in activit~ to a complete loss of *Trade Mark . . ",, ;: ' ' ~',' '` ` ~' ` ~'' '' ` , ~- ... _ _ , .

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effectiveness at the 15 day test. Similarly, the confetti gave high activity through the 15 day period, with loss of effectiveness at the 29.day reading, but the treated filter paper was active o,nly on the first test day (Table 3).
The sheet and confetti forms of the dispensers of this invention containing the Bioresmethrin dramatically extended the residual activity of this light degradable compound.

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~04~9S0 Exam~le 10 -The polymeric dispensers of this invention have the unique ability to protect active ingredients from degradation, thus prolonginq the effective life of the insecticide, ~ith-out increasing its persistence in the environment. This Example demonstrates the effective life of several dispensers containing ~lathion, Diazinon~ chlorpyrifos, Fenchlorophos, chlordane and carbaryl. All samples contained between 4~
and 11~ insecticide based on the total weight of the dispens-er.
According to the test procedure, American cock-roaches were added monthly to open top jars whose bottoms were covered with the ins~cticidal dis~ensers. The time it took to kill 100~ of the roaches placed in the jars was rey-istered and shown in Table 4 as a function of time from the day of preparation of the dispensers. Between tests the dispensers in the open top jars were exposed to the atmo-spheric conditions of the room (approximately 70F and 40 RH ) . , :
The results shown in ~able 4 indicate that all dis-pensers were capable of killing normal American cockroaches with undiminished strength after periods of as long as 15 months.

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10~9~0 Example 11 Three dispensers prepared in accordance with Ex-ample 1 and containing 31.5% chlorpyrifos, 22.4~ C arbaryl ald 40% Chlordane, respectively, were placed in a ~eatherometer to investigate the effect of adverse environmental conditions on the ability of the dispensers to kill non-resistant Ameri-. can cockroaches. The arc of the weatherometer was operatedat 60 amps and 50 volts and the apparatus was o~erated in such a wa~ that the samples ~ere exposed to successive cycles of 102 minutes of light without water spray and 18 minutes with spray at 80F. (Fed. Test Method Std. No. 191 ~lethod 5804).
Aft~r exposure for 250 hours, the three samples were tested for anticockroach activity as set forth in Ex-ample 10.
The dispensers containing chlorPYrifos and Carbaryl showed 100% kill within one day and the Chlordane sample after four days.
After 500 hours exposure in the weatherometer the three samples were tested again. The Chlorpyrifos and Car-baryl dispensers again showed 100~ kill within one day and the Chlordane sample produced 100~ kill after three days.
Example 12 Proper use of the polymeric dispensers indoors will require ~no~ledge of the amount of roach toxicant entering the surrounding environment. In Figure 1 the cumulative loss of toxicant as a function of time has been determined for the five dispensers of the type described in E~amples 1, 3, 6, 7 and 8 and containing the to~icants in th2 follo~ing amoullts:
Chlorp~rifos - 30.8~, Chlordane - 19.3~, Diazinon - 21.2~, .
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Malathion - 33.7~ and Carbaryl - 22.7~. The weighings were performed against controls, thus minimizing errors due to mQisture absorption. I~ is apparent that the loss due to evaporation of toxicant as it ~ecomes available on the sur-face of the dispensers is linear with time. In the case of Malathion, ho~ever, a parabolic curve ~ras obtained and it is believed that the initial high release rate was caused by volatile impurities in the technical grade Malathion. The cumùlative loss for any of the insecticides in this graph was less than 5% per month. Figures 2 and 3 show cumulative diffusion losses, as a function of insecticide concentration, for Malathion and chlordane. It is significant that the losses for the insecticides were not related to the vola-tilities of the pure materials, as shown below in Table 5, indicating that the control upon the rate of loss is the rate j of migration of the toxicant throug~ the polymeric matrix.
Table 5 Insecticide ~ or Pressure mm Hg Temp~rature C
Malathion4 x 10-5 30 Chlorpyrifos1.2 x 10-3 25 Fenchlorphos.8 x 10-4 25 Diazinon *2.8 x 10-4 30 Chlordane4 x 10-4 - 25 Carbaryl< S x 10-3 26 Examples 13 - 18 Dispensers prepared senerally in accor~ance with Example 1 were tested by the U. S. Department of ~griculture - Agricultural Research Service at Gainesville, Florida, with the results set forth in Table 7.

*Trade Mark 1(~419SV

Procedure For Residue Tests Compounds that produce 75% to 100~ knockdown and kill within 24 hours as a 2.0% contact spray are tested as residues on 6 x 6 inch panels of 1/4-inch plywood. Acetone solutions of the insecticides are sprayed on plywood panels at the rate of 100 mg of active ingredient per s~uare foot.
When warranted, water suspensions and emuLsions are substi-tuted for the acetone solutions. The treated panels are allo-~ed to dry for 2 hours, then 20 adult male cockroaches (two replicates of 10 each) are ex~osed to the residues for 30 minutes. Exposures to the treated surfaces are made under -- inverted plastic dishes coated on the inner surface with pyrophyllite, which prevents the coc~roaches from cra~ling up the sides. At the conclusion of the exposure period, the cockroaches are transferred to clean petri dishes. Observa-tions on knockdown and kill are made at this time and after 24 and 48 hours. The treated panels are then allowed to age and are tested at intervals of 1, 2 and 4 weeks, or longer if necessary, depending on the effectiveness of the residues.
All tests are conducted in duplicate in comparison to a chlordane standard.
~ able 6 Results of standard screening tests with insecti-cides applied to plywood panels and evaluated for residual effecti~eness against German cockroaches.

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Table 6 (cont'-d) Percent mortality on xesidues aged for indicated period Insecticid~ : 2 hr : 1 ~k : 2 wk : 4 wk : 8 wk Carbaryl 0 0 Chlordane 100 60 0 0 Chlorpyrifos100 100 100 65 0 Diazinon 100 90 0 0 Malathion 25 25 10 ~ Propoxur 100 9S 100 70 0 Check 0 0 0 0 0 _, .
Table 7 ` - ~ Residual evaluation of Herculite fa~ric dispensers .
on plywood against normal Blattella germanica. (Dispensers stapled on plywood for standard exposure method; 2 tests with 10 adul' maIes each; 30-min exposure mortality assessed after 48 h~).

Percent mortality on treated fabrics after indicated wee~
of testinga/
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Ex. No. Insecticide : (~) O~J : 1 : 2 : 4 : 8 Residues on Herculite Fabric * Dis~ensers 13 Carbaryl 22 0 0 14 Chlordane 40100 100 100 100 100 Chlorpyrifos 27100 100 100 100 100 16 Diazinon 21100 100 100 100 100 17 ~lalathion 25 0 0 0 0 18 Propo~ur* 23100 100 100 100 100 a/ No mortality in chec~s.
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From the foregoing it is apparent that this inven-tion will provide efficacy against German and American cock-roaches. The dispensers are particularly valuable for the application of light-sensitive agents or any agent ~hich deqrades upon exposure to atmospheric conditions. Further-more, insecticide losses are controlled to a predictable rate, consistent with prolonged effectiveness, ~7ithout increasing persistence in the environment.
While the efficacy of the products of the present invention has been demonstrated in this application primarily by evidence of efficacy against the cockroach species, ~hich is a particularly hard to kill insect, it will be understood that the products are also useful against other insects in-cluding bùt not limited to ants, eanYigs, flies, millipedes, mosquitoes, spiders, crickets, clover mites, fleas, scorpions, sowbugs, ticks, coaterbugs, saw-toothed grain beetles, silverfish, sod webworm, lawn chinch bugs, sand flies, bill-bugs, punkies, bollworms, grasshoppers, stink bugs, corn ean~orm, Japanese beetle, fowl mites, lice, tobacco flea beetle, and a ~ide variety of other agriculturally destruc-tive beetles, borers, slugs, suc~ers, aphids, moths, miners, . scales, worms, etc.
Throughout the specification the applicant has referred to certain insecticides by their trade name or trade mark for the purposes of simplifying the description and claiming of the applicant's invention. Nevertheless, a list of the chemical names for certain insecticides referred to in the C ~, specification follows:
Chlorpyrifos is O,O-Diethyl 0-(3, 5, 6- -Trichloro-2-Pyridyl) Phosphorothioate Diazinon is O,O-Diethyl 0-2-Islpropyl-4-Methyl - Pyrimidyl Thiophosphate *

Chlordane is 1, 2, 4, 5, 6, 7, 8, 8-Octachloro-3a, 4, 7, 7a - Tetrahydro- 4, 7 -Methanoindan Carbaryl is l-Nophthyl N-Methylcarbamate Malathion is S-(l, 2 - Dicarbethoxyethyl) -O,O-Dimethyl - Dithiophosphate Bioresmethrin is d-Trans resmethrin or (5-Benzyl-3- Furyl) Methyl- 2,2-Dimethyl -3 - (2-Methylpropenyl) Cyclopropanecarboxylate Fenchlorphos is O,O-Dimethyl - 0-(2, 4, 5-Trichlorophenyl) - f Phosphorothioate Propoxur is o-isopropoxyphenyl methylcarbamate : 20 : 30 ` * Trade Mark

Claims (14)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A dispenser for insecticidal agents contact-effective against cockroaches and other crawling insects comprising a co-extensive four-layered solid non-porous strip formed from the lamination of layers comprising:
an outer layer, exposed on a first surface to the atmosphere, of a solid sheet of polyvinyl chloride through which the insecticidal agent is capable of migrating by molecular migration to become available at said first surface;
laminated at the second surface to at least one core layer of a solid non-porous layer of a solidified polyvinyl chloride plastisol containing an essentially non-volatile, contact-effective anti-cockroach agent selected from the group consisting of Chlorpyrifos*, Diazinon*, Chlordane*, Carbaryl*, Malathion*, Bioresmethrin*, Fenchlorphos*, Propoxur*, and mixtures thereof in an amount of at least 10% by weight of the total weight of the laminate;
attached at the side opposite said outer layer to a solid sheet of a polymeric material which is a barrier to said molecular migration of the agent, attached at the side opposite said core layer to a layer of a pressure-sensitive adhesive to permit mounting of said strip on a surface compatible with said adhesive, said first surface of the outer layer being supplied continually with an effective level of agent from the core for a period of at least about 4 months from the time of deployment in the atmosphere.

2. The dispenser of Claim 1 wherein said barrier is a sheet of material selected from the group consisting of nylon and MYLARR.

*Trade Mark 23

3. The dispenser of Claim 1 or 2 wherein the thickness of said outer layer is from about 1 to about 10 mils, the thickness of said core layer is from about 2 to about 20 mils, and the total thickness of said laminated article is up to about 30 mils.

4. The dispenser of Claim 1 wherein said agent is Chlorpyrifos*.

The dispenser of Claim 1 wherein said agent is Diazinon*.

6. The dispenser of Claim 1 wherein said agent is Chlordane*.

7. The dispenser of Claim 1 wherein said agent is Carbaryl*.

8. The dispenser of Claim 1 wherein said agent is Malathion*.

9. The dispenser of Claim 1 wherein said agent is Bioresmethrin*.

10. The dispenser of Claim 1l wherein said agent is Fenchlorphos*.

11. The dispenser of Claim 1 wherein said agent is Propoxur*.

12. The dispenser of Claim 4, 5 or 6 wherein the thickness of said outer layer is from about l to about 10 mils, the thickness of said core layer is from about 2 to about 20 mils, and the total thickness of said laminated article is up to about 30 mils.

13. The dispenser of Claim 7, 8 or 9 wherein the thickness of said outer layer is from about 1 to about 10 mils, the thickness of said core layer is from about 2 to * Trade Mark 24

Claim 13 - cont'd ,..., about 20 mils, and the total thickness of said laminated article is up to about 30 mils.

14. The dispenser of Claim 10 or 11 wherein the thickness of said outer layer is from about 1 to about 10 mils, the thickness of said core layer is from about 2 to about 20 mils, and the total thickness of said laminated article is up to about 30 mils.