Abstract:
An insect bait-and-switch liquid delivery apparatus for the control of flying insects, especially wasps. The apparatus includes a container for holding liquid bait, a feed station assembly mounted on the container for making the liquid bait available to an insect, and a cover enclosing the feed station assembly. The feed station assembly includes a tubular core which extends into the interior of the container for supporting a capsule containing liquid active toxic to the insect in an upright orientation so that it floats on the liquid bait. As the liquid bait is depleted due to the feeding action of insects, the capsule moves downwardly until it clears the lower end of the tubular core whereupon it tips and releases the liquid active to admix with the liquid bait. Thereafter, as the insects continue to feed they ingest a mixture of the liquid active and liquid bait. Thus, as the insects travel back and forth from the apparatus to their nest, the active is spread throughout all the insects in the colony resulting in irradication of the entire insect colony.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to the field of insect control, and more particularly to a bait-and-switch liquid delivery apparatus for the control of insects. 
     Various traps and other types of insecticide delivery systems have been developed in an attempt to control flying insects with varying degrees of success. Insecticide delivery systems are sometimes categorized as being either of the “quick kill” variety or of a “delayed kill” type. 
     Quick kill systems use pesticides that kill shortly after contact or ingestion. Quick kill pesticides are usually used in aerosol and spray insecticide systems. Unfortunately, quick kill pesticides are typically only effective on individual or very small groups of insects, and thus the entire colony of insects cannot be irradicated unless the entire colony is exposed to the quick kill pesticide. Such exposure can rarely be accomplished due to the limitations of dispensing such pesticides. 
     Pesticides which have a “delayed kill” action are most useful against social insects such as wasps and bees. If a “delayed kill” pesticide is ingested by wasps and bees, the active substance toxic to the insect will be carried back to the home colony where it will be shared by other members such as larvae, workers, and the queen. If sufficient toxicant is transported back into the home colony, it is possible to irradicate the entire colony. In order to assure that sufficient toxicant is carried back to the nest or home colony, the formulation containing the active toxicant must be palatable to the insect. 
     Wasps, which include such species as yellow jackets and hornets, are generally categorized as feeding source generalists. However, wasps are quite sensitive to the presence of adulterants in food. Thus, palatable toxicant formulations must be carefully prepared so that the levels of toxicants, surfactants and other substances are carefully blended to provide an attractive bait. However, degradation of the toxicant often times results in bait which, although initially attractive, ultimately becomes unpalatable. 
     An approach to getting wasps such as yellow jackets and hornets to ingest a toxicant that has been found very effective has been called the “bait-and-switch” technique. This technique essentially allows the wasps to become accustomed to a liquid food source containing no toxicants, i.e. a liquid formulated with bait only which is attractive to the insect during an initial feeding period. As a result, these insects are baited or trained to continue feeding from what they consider to be a palatable formulation even after a toxicant is added to the formulation. For such a method to be convenient and effective, a specialized delivery system needs to be employed. 
     SUMMARY OF THE INVENTION 
     The present invention provides an insect bait-and-switch liquid delivery apparatus for the control of flying insects, especially wasps. The apparatus provides an economical and easily manufactured insect bait station that can contain a liquid insect bait and a liquid insect active substance toxic to the insects in such a way as to provide a very effective bait-and-switch apparatus to kill targeted insects. In particular, the apparatus trains wasps to become accustomed to a liquid food source containing no toxicants, i.e. a bait only formulation, so that they subsequently continue feeding from the source after a toxicant is added to the formulation after an initial feeding period. The active ingredient is added automatically to the bait without any further specific positive action by the end user or consumer who purchases the apparatus. 
     The apparatus has a first reservoir containing a first liquid formulated with a bait attractive to an insect, a feeding station for making liquid from the reservoir available to an insect, a conveying means for conveying liquid from the reservoir to the feeding station, a second reservoir containing a second liquid formulated with an active substance toxic to the insect, the second reservoir floating on the bait-only liquid in the first reservoir, and means sequentially operable to initially prevent admixing of the second toxic liquid with the bait-only liquid during an initial feeding period, but after the initial feeding period, to subsequently enable admixing of the liquid active with the liquid bait to provide a bait-active mixture which is conveyed to the feeding station. In this manner, the insect is initially trained to become accustomed to a liquid food source, and thereafter to continue feeding from the source after a toxicant is added to the formulation. Thus, as the insects travel back and forth from the apparatus to their nest, the active toxin is spread throughout the entire nest to exterminate all members of the nest without the time consuming necessity of actually physically locating the nest or the relatively dangerous activity of directly spraying the nest with a quick kill insecticide. 
     In order to accomplish the above, the apparatus has three main components. An open top container forms the reservoir for containing the liquid bait, a feed station assembly mounted on the container, and a cover for enclosing the feed station and providing a means for hanging the apparatus in a location known to be frequented by the target insect. The feed station assembly includes a support for an absorbent pad which provides a substantially flat feeding surface, and which is connected to an absorbent wick which extends into the interior of the container so that its free end contacts the liquid within the container. This wick conveys liquid from the first reservoir within the container to the flat feeding surface of the absorbent pad. The feed station assembly also includes a series of access ports allowing the insects to reach and feed from the absorbent feeding pad. The feed assembly also includes a central tubular core which extends from the pad support into the interior of the container and terminates with an open bottom end at a desired spaced distance from the bottom surface of the container. 
     The second reservoir comprises a capsule containing the liquid formulated to be toxic to the insect. The capsule is comprised of a frangible glass ampoule containing the active liquid contained within a plastic deformable sleeve. The glass ampoule is mounted between a buoyant float at one end of the sleeve and a liquid permeable member at the other end of the sleeve. The capsule is mounted within the central core in an upright orientation so that it floats on the liquid bait in the reservoir with the permeable end of the capsule out of contact with the liquid. As the liquid bait is depleted due to the feeding action of insects on the absorbent pad, the capsule slowly moves downwardly toward the lower end of the central core. Eventually, as the level of the liquid in the container continues to decrease, the capsule clears the lower end of the central core. The float then ensures that the capsule tips sideways enabling the toxin to admix with the liquid bait through the permeable member. Thereafter, as the insects continue to feed, they ingest the liquid active and the liquid bait. Thus, as the insects travel back and forth from the apparatus to their nest, the active is spread throughout all the insects in the colony resulting in irradication of the entire insect colony. 
    
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
     In the drawings: 
     FIG. 1 is a perspective view of the bait-and-switch liquid delivery apparatus constructed in accordance with the present invention; 
     FIG. 2 is an exploded perspective view of the components of the bait-and-switch apparatus of FIG. 1; 
     FIG. 3 is a cross-sectional view taken along the line  3 — 3  in FIG. 1; 
     FIG. 4 is a cross-sectional view taken along the line  4 — 4  in FIG. 3; 
     FIG. 5 is an enlarged detailed view of the capsule containing the toxic liquid active; 
     FIG. 6A is a fragmentary cross-sectional view illustrating the initial set-up stage of the apparatus; 
     FIG. 6B is a fragmentary cross-sectional view illustrating the capsule about to clear the lower end of the central core; 
     FIG. 6C is a fragmentary cross-sectional view showing the capsule admixing the toxic liquid active with the liquid bait; 
     FIG. 7A is an exploded perspective view illustrating the manner of assembling the main components of the apparatus; 
     FIG. 7B is a fragmentary perspective view illustrating the activation of the apparatus; and 
     FIG. 7C is an exploded perspective view illustrating the final assembly of the components of the apparatus. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring now to the drawings, there is illustrated an insect bait-and-switch liquid delivery apparatus for the control of flying insects, preferably wasps such as yellowjackets and hornets. It should be noted, however, that although the specification specifically refers to wasps, the invention is applicable to all types of “social” insects such as ants, termites, wasps, yellowjackets, hornets and bees. Only minor modifications need be made to the basic concept of the present invention to provide an apparatus that is adapted for crawling social insects such as ants and termites rather than the flying social insects in which the present specification is specifically directed. Therefore, the following apparatus may be useful to control all types of insects that can easily assimilate food when it is in a liquid or liquifiable form. Likewise, although a specific liquid bait formulation and specific liquid active formulation may be described herein, these formulations can readily be modified and adapted to a particular target insect. Thus, the apparatus described herein may be useful with a myriad of different liquid formulations. 
     Referring now to FIGS. 1-3, there is illustrated an insect bait-and-switch liquid delivery apparatus generally designated by the numeral  1  which includes three main components, i.e. an open top container  2  defining an internal chamber or reservoir  3 , a feed station assembly generally designated by the number  4 , and a cover  5 . Referring first to container  2 , FIGS. 1-3 illustrate that it is preferably cylindrical in shape having a neck portion  6  at its upper end with external threads  7  integrally formed therein. Container  2  is preferably formed of a semi-transparent plastic material such as high density polyethylene which enables an end user to physically see the level of liquid contained within reservoir  3 . As illustrated, the depth of container  2  is substantially greater than its width which advantageously permits ready handling of the apparatus  1  by an end user. 
     Reservoir  3  initially contains a liquid bait formulated substantially free of any insect-toxic substances and of a composition that is attractive to the target insects. The optimal liquid bait preparation contains 10% to 20% corn syrup, 5% to 15% sucrose, 0.5% to 5% maltodextrine, 1% to 10% of a protein, and 0.001% to 0.20% of a preservative, with the balance of the composition being water. Although this liquid bait composition is preferred, it is clear that other compositions may be utilized, depending on the target insect. For example, liquids may be oils or water and oil emulsions. Food ingredients can include amino acids, vitamins, salts, and trace elements. 
     Feed assembly  4  is composed of numerous components with one of the primary components being circular shaped housing  8 . Housing  8  includes a base  9  integrally formed with a central hub  10  which defines a central opening  11  extending completely through assembly  4 . A plurality of upstanding walls or spokes  12  are circumferentially spaced apart from one another and extend radially outwardly from hub  10 . A circular ring  13  is mounted at the radially outer end of each spoke  12  such that the upper edge  14  of ring  13  and the upper edges  15  of spokes  12  are flush with one another and are located in a substantially planar relationship to one another to provide a support for an absorbent pad  46  hereinafter to be described. Ring  13  is supported by a plurality of upstanding walls  17  each extending between ring  13  and base  9 . Walls  17  provide rigidity and support for both ring  13  and spokes  12 . Preferably, housing  8  is molded in one piece from a plastic material to minimize costs. Central hub  10  of assembly  4  also includes an upper wall  18  which, as illustrated best in FIG. 3, is also planar with upper edges  14  and  15  to provide further support for pad  16 . 
     As also shown best in FIGS. 2 and 3, hub  10  receives the upper end of a central tubular-shaped core  19 . The upper end of core  19  includes a flange  20  having an outer circumferential surface  21  substantially matching the inner circumferential surface of hub  10 . Flange  20  also includes a cutout portion  22 , the purpose of which will hereinafter be described. The upper end of core  19  and flange  20  form a step  23  which cooperates with a flange  24  depending from the underside of hub  10  to properly locate core  19  in hub  10  with respect to housing  18 . As shown best in FIG. 3, core  19  terminates at a lower end  25  which is spaced a desired distance from bottom wall  26  of container  2 . The distance between the lower end  25  and bottom wall  26  must be greater than the length of capsule  57 , as will hereinafter be understood. 
     It should be noted that core  19  has a constant inner diameter defined by inner surface  27  throughout its length. However, referring to FIG. 4, there is illustrated a plurality of ribs  28  extending longitudinally along the entire length of core  19 . Ribs  28  also extend radially inwardly from inner surface  27  to provide a means for supporting capsule  57  in its upright orientation and for guiding capsule  57  within core  19  as it moves downwardly therein which will hereinafter be described. Thus, ribs  28  reduce the friction that normally would occur between inner surface  27  and capsule  29  as it travels downwardly through core  19 , and tends to prevent capsule  29  from “sticking” to the inner surface  27  of core  19 . 
     Assembly  4  further includes a lid  30  having a top wall  31  and a circular depending flange  32  having internal threads  33  integrally formed therein for threadedly engaging the external threads  7  of container  2 . Top wall  31  includes a central opening  34  formed therein which enables core  19  to pass therethrough so that lid  30  can be positioned in engagement with the underside of flange  20 , as best shown in FIG.  3 . Assembly  4  also includes a deformable plastic bulb  35  which receives capsule  57  therein. Bulb  35  has a closed upper end and an open lower end for receiving capsule  57 . A flange  36  projecting radially outwardly from the lower end of bulb  35  is used to mount bulb  35  on housing  8  as will hereinafter be described. 
     A means for clamping bulb  35 , core  19  and lid  30  to housing  18  completes feed assembly  4 . The clamping means comprises an upper clamping plate  37  and a lower clamping plate  38  which sandwiches flange  36 , upper wall  18 , flange  20  and top wall  31  therebetween. In order to accomplish this, plate  37  includes a pair of depending bosses  39  and a central opening  40  for receiving bulb  35 . Likewise, lower clamping plate  38  includes a pair of upstanding bosses  41 . Bosses  39  extend downwardly through a pair of matching openings  42  in flange  36  of bulb  35  and through a pair of aligned openings  43  in upper wall  18  of hub  10  into a pair of aligned openings  44  in flange  20 . Likewise, upstanding bosses  41  extend through aligned openings  45  in top wall  31  of lid  30  and into openings  44  in flange  20 . Bosses  39  and  41  are then sonically welded to provide the one piece feed assembly  4 . 
     An absorbent feeding pad  46 , preferably made of a cellulose material, is disc-shaped and provides a flat feeding surface  47 . In apparatus  1 , feeding surface  47  is actually the underside of pad  46 . The outer diameter of pad  46  substantially matches the diameter of ring  13  so that housing  8  provides adequate support thereof in a substantially planar manner. Pad  46  includes an integral wick  48  depending therefrom. Wick  48  is composed of the same cellulose material as pad  46 . As shown best in FIG. 3, wick  48  has a length which enables it to substantially extend downwardly into container  2  such that its free end  49  bears against bottom wall  26  of container  2 . This ensures that the liquid contained within reservoir  3  substantially impregnates wick  48 . Thus, liquid from reservoir  3  moves upwardly by capillary action and impregnates the feeding pad  46 . Pad  46  also includes a central cutout portion  50  which enables bulb  35  to pass therethrough and permit pad  46  to be supported by housing  8 . Thus, housing  8 , in combination with pad  46  forms a feeding station for flying insects such as wasps. As shown best in FIG. 1, base  9 , spokes  12 , ring  13  and upstanding walls  17  form a series of circumferentially spaced access ports  51  which allow insects to reach and feed from the underside surface  47  of absorbent feeding pad  46 . As the wasps feed on the liquid impregnated pad  46 , wick  48  continuously draws further liquid from reservoir  3  upwardly to replenish what is lost from this feeding as well as evaporation. Thus, as the wasps feed, the level of liquid within reservoir  3  slowly lowers. 
     The final component of apparatus  1  is cover  5 . Cover  5  is dome-shaped and includes a lower cylindrical lip  52  which is formed to snap fit over ring  13  and thereby enclose pad  46 . A central opening  53  in the top of cover  5  enables a string, wire, cable or the like  54  to extend therethrough. The lower end of string  54  includes a stop  55  to prevent the string  54  from passing completely through opening  53  while the upper end of string  54  includes a hanger  56  which is used to hang apparatus  1  in a location known to be frequented by wasps, which are the preferred target insects. The dome shape of cover  5  aids in keeping environmental elements such as rain from contacting absorbent pad  16 , and its snap fit with ring  13  aids in minimizing evaporation of liquid from pad  16 . 
     Referring now to FIG. 5, there is illustrated a second reservoir generally designated by the numeral  57  containing a liquid formulated with an active substance toxic to the insect, sometimes referred to herein as the “liquid active”. The preferred active or toxicant is an effective concentration of a hemisalt preparation of perfluoroalkane sulfonic acid. A sufficient amount of the active is used so that a concentration of 0.001% to 1.5% by weight, preferably 0.02% to 0.03%, by weight of the active is supplied when the active is admixed with the liquid bait, as will hereinafter be described. The hemisalt preparation, being a partially neutralized preparation of perfluoroalkane sulfonic acid, is not very acidic, has sufficient water solubility and produces a toxicant attractant formulation that is very attractive to wasps. The hemisalt preparation is also stable in carbohydrate solutions, the preferred insect attracting ingredient for such insects. The hemisalt of perfluoroalkane sulfonic acids can be made by mixing an aqueous solution of a base with an aqueous solution of the acid to prepare an aqueous formulation having a pH between 2.8 and 6.5, preferably a pH of 4.0 to 6.5, and most preferably a pH of 5.0 to 6.0 with an optimal pH of 5.5. The base used to neutralize the sulfonic acid is selected from the group consisting of hydroxides of sodium, potassium, lithium, calcium, magnesium, zinc, aluminum or zirconium; ammonium hydroxide; primary, secondary, or tertiary amines; primary, secondary or tertiary alkanolamines; or tetra alkylammonium hydroxides, wherein the alkyl is preferably methyl, ethyl, propyl, or butyl. Although the above hemisalt preparation is preferred, other toxicants such as sulfluramid, abamectin, and hydramethylnon may also be utilized. 
     The active or toxicant is provided within the reservoir or capsule  57 , and is contained within a frangible, glass ampoule  58 . The ampoule  58 , in turn, is contained within a plastic sleeve  59 . The sleeve  59  is closed at one end and open at its other end, and contains a float  60  attached at its closed end and a stopper  61  at its open end. Float  60  may comprise any material having a specific gravity less than  1  to ensure that capsule  57  floats in an upright orientation on the bait liquid in reservoir  3 , as will hereinafter be described. The float  60  may thus be comprised of any buoyant material, but preferably is composed of a closed cell urethane foam. Stopper  61  is composed of a liquid permeable or porous material and closes the mouth or upper end of sleeve  59 . The stopper  61  may be composed of any material which allows release of the liquid active within ampoule  58  into the liquid bait in reservoir  3  when desired, such as cotton or glass wool. A plastic collar  62  surrounds sleeve  59 , and as shown best in FIG. 5, collar  62  is slightly tapered from top to bottom. This taper minimizes friction between the external surface of collar  62  and ribs  28  of core  19  so that capsule  57  may readily progress downwardly within core  19  without sticking as the level of liquid bait drops in reservoir  3 . 
     Referring now to FIGS. 7A-7C. There is illustrated the sequential operation for use of the bait-and-switch apparatus  1 . When the apparatus  1  is unpackaged, capsule  57  is located within bulb  35 , and absorbent pad  46  and wick  48  are initially separate from container  2 , feed assembly  4  and cover  5 . A tab  63  initially blocks an access hole  64  in upper clamp plate  37 . As seen best in FIG. 2, access hole  64  is aligned with a similar hole  65  in flange  36  of bulb  35  which in turn is aligned with another similar hole  66  in top wall  18  of hub  10  as well as cutout portion  22  in flange  20  of core  19 . Cutout portion  22  in turn is aligned with a pie-shaped opening  67  in top wall  31  of lid  30  and cutout  68  of lower clamping plate  38 . As noted, tab  63  initially blocks access through all of openings  64 - 68 , but when an end user desires to begin using apparatus  1 , the end user removes tab  63  and inserts wick  48  down through the aligned openings  64 - 68  into the liquid bait contained within the liquid reservoir  3  so that the end of wick  48  touches bottom wall  26 , and pad  46  is supported on feed assembly  4  to provide the substantially planar feeding surface  47 , as best shown in FIG.  3 . Thereafter, the end user grasps bulb  35 , squeezes it and perhaps bending it slightly to one side, until glass ampoule  48  breaks to release the active into reservoir or capsule  57 . This is illustrated by the arrows  69  of FIG.  7 B. The end user then pushes directly downwardly on the top end of bulb  35 , as illustrated by the arrow  70  in FIG. 7C, forcing capsule  57  downwardly into the upright tube or core  19  wherein capsule  57  floats on the surface of the liquid bait, as best shown in FIG.  6 A. Finally, the end user snaps cover  5  in place on ring  13 , and then apparatus  1  is hung by means of hanger  56  a location known to be frequented by wasps, such as yellowjackets and/or hornets which are the preferred target insects. After positioning apparatus  1  at the location desired, there is no need for an end user to have any physical contact with the apparatus  1  again, until such time as the end user wishes to remove apparatus  1  to dispose of it. 
     Referring now to FIGS. 6A-6C, there is illustrated the operation of apparatus  1 . FIG. 6A illustrates the initial stage of apparatus  1  as it is hung in position at a desired location. Initially, liquid bait rises through wick  48  wetting pad  46 . The feeding surface  47  of pad  46  is thus exposed to wasps for feeding via the access ports  51 . As wasps feed on liquid bait, the level of liquid bait drops until eventually the level of liquid bait reaches the open bottom end of core  19 , as best shown in FIG.  6 B. At this time, capsule  57  will begin to try and tip away from its vertical, upright orientation due to the buoyancy of float  60 . Eventually, the level of liquid bait drops sufficiently below the end of core  19  so that capsule  57  escapes from the open lower end of core  19 . When this happens, capsule  57  tips to one side and releases the liquid active into the liquid bait, as shown best in FIG.  6 C. The liquid active is admixed with the liquid bait through various mechanisms, typically the active of wind causing apparatus  1  to gently swing back and forth until all of the active or toxicant is admixed with the liquid bait. Thereafter, the liquid bait and liquid active combination begins to rise via wick  48  to pad  46 . The wasps, having been trained to feed from pad  46  blindly continue to feed from the bait/toxicant formulation at the same location. The wasps, i.e. yellowjackets and hornets will carry the bait-toxicant formulation back to their home colony where it will be shared by larvae, workers, and the queen until sufficient toxicant is transported back into the nest whereby the entire colony is irradicated within a week or two.