AU2012350104B2

AU2012350104B2 - Apparatus and method for reducing populations of mosquitoes and the like

Info

Publication number: AU2012350104B2
Application number: AU2012350104A
Authority: AU
Inventors: Kristian J. K. Holland; Ashwani Kapur; Tim Mackay; Gerardo Ulibarri; Kailash C. Vasudeva
Original assignee: MAXTECH MOSQUITO CONTROL Inc
Current assignee: MAXTECH MOSQUITO CONTROL Inc
Priority date: 2011-12-06
Filing date: 2012-12-06
Publication date: 2018-05-10
Anticipated expiration: 2032-12-06
Also published as: GB2515406B; CA2760919A1; CA2760919C; AU2012350104A1; GB201411626D0; GB2515406A; ZA201404582B; WO2013082700A1

Abstract

The apparatus has a drainable basin (2) for retaining a liquid, typically water, preferably augmented by insect attractant(s). The basin has a drain (6) at a lower portion thereof, with a valve (7) to open or close the drain. The drain leads to a filter (8) which removes eggs and larvae from the liquid when the basin is drained by opening the valve. The liquid passing through the filter is collected in a reservoir (3), from which the filtered liquid may be pumped back up to refill the basin. The apparatus preferably may use a variety of standard containers, the container (4) then acting as the reservoir. Preferably, one or more insect attractant means are employed, including various chemical attractants and light, as well as natural attractants. Vents (30) from the reservoir release attractants concentrated in the reservoir, into the area of the basin. Two or more units may have their reservoirs connected to each other, or may share a common reservoir. In operation, the basin is filled with liquid, preferably with one or more attractants being employed, and the liquid remains in the basin for a period of time for eggs and larvae to accumulate, but not long enough to mature. The basin is then drained through the filter into the reservoir. The basin is then refilled from the reservoir and the cycle begins again. Optionally, the apparatus may be automated, and the method may be carried out automatically with only periodic maintenance.

Description

FIELD OF THE INVENTION

This invention relates to an insect population reduction apparatus and method. In particular, the invention relates to an apparatus and method for reducing maturation of aquatically hatched insects, including but not limited to mosquitoes.

BACKGROUND OF THE INVENTION

It is well documented that biting insects, specifically Culicidae (mosquitoes), are vectors for many diseases throughout the world. In an effort to eliminate insect-borne diseases, such as malaria, dengue fever, West Nile disease, etc., extensive efforts have been carried out worldwide to diminish or eliminate these insects from areas inhabited by humans.

The use of pesticides, such as larvicides, adulticides, Dichloro-Diphenyl-Trichloroethane (DDT) and malathion, to control insects over large areas and the problems associated therewith are well documented. Serious long lasting consequences to both the environment and human health have resulted from the use of such pesticides. The use of pesticides is not desired for environmental reasons, and some of these chemicals are known to repel insects, thereby decreasing the effectiveness of these methods. Furthermore, there is evidence that some species of insects are beginning to become resistant to these chemicals.

To control insects in more localized areas, such as backyards, various traps have been developed. These traps include bug “zappers” and devices that release various gases to attract the insects. The primary purpose of these traps is to immediately eliminate the insects. However, these techniques do not prevent the population from growing from eggs and larvae that exist in the breeding ground of these insects.

In addition to the preceding methods, attempts have been made to provide artificial breeding pools that trap the hatching insects. For example, US Patent No. 5,896,697 discloses an artificial breeding pool where the eggs are trapped behind a screen that prevents the newly

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2012350104 26 Apr 2018 hatched mosquitoes from escaping into the environment. US PatentNo. 3,997,999 discloses an apparatus that traps newly hatched mosquitoes in a separate column from where the eggs were laid.

Artificial breeding pools that eliminate the newly laid eggs or larvae have also been 5 contemplated. For example, US Patent No. 6,708,443 discloses an apparatus where the artificial breeding pool contains a filter that traps the eggs and larvae and then exposes the captured biomass to air causing the biomass to dry and thus be eliminated. US Patent No.

6,990,768 discloses a similar apparatus with the exception that the filter is provided in the form of a belt that captures the biomass and then passes it through a crushing mechanism to eliminate the eggs and larvae.

Although standing water will naturally attract most insects that rely on water to lay their eggs, it is known that chemical attractants can be added to the water to increase the attractiveness of the pool to the pregnant insect. For example, US Patent Publication No. 2008/0003197 discloses a controlled release attractant for use in an artificial breeding pool.

Research has shown that after eggs are laid, a chemical cue is released that signals to other mosquitoes that the location is a successful breeding site, which in turn attracts other mosquitoes to lay their eggs. Most of this chemical cue is thought to be released after hatching. The natural chemical cue is a very effective attractant, and acts synergistically with any attractant already in solution. Accordingly, if this natural chemical cue could be preserved and concentrated over time, the trap would be more effective in attracting mosquitoes from a larger area.

SUMMARY OF THE INVENTION

Embodiments of the invention provide an apparatus and method for reducing populations of aquatically hatched insects that addresses limitations of the prior art.

In a first aspect the present invention provides a system for reducing populations of aquatically hatched mosquitoes, the system comprising:

a plurality of trap assemblies each comprising a basin for selectively retaining a liquid, the basin having a drain opening and a valve below said drain opening for selectively opening and closing said drain opening;

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2A

2012350104 26 Apr 2018 a filter connected to receive liquid from each said basin via respective drain opening or a filter securable to each basin to receive liquid from each basin via said drain opening;

said filter having openings sized sufficiently small to collect eggs and larvae of the 5 mosquitoes and permit the passage of said liquid;

a reservoir to collect liquid passing through said filter, the filtered liquid from each of said basin mixed in the reservoir; and a pump to return liquid from said reservoir to each said basin.

In a second aspect the present invention provides a method for reducing populations of 10 aquatically hatched mosquitoes, the method comprising the steps of:

a. providing a system according to the first aspect;

b. filling the basins with liquid;

c. leaving the liquid in the basins for a period of time sufficient for eggs and larvae of the insects to accumulate, but not long enough to mature;

d. then operating said valves to drain the basins and to pass the liquid thence through said filters into said reservoirs;

e. then closing said valves and operating said pumps to refill said basins; and

f. repeating the preceding from step c.

According to one aspect of the invention the apparatus has a drainable basin for retaining a 20 liquid, typically water, preferably augmented by insect attractant(s). The basin has a drain at a lower portion thereof, with a valve or the like to open or close the drain. The drain leads to a filter which removes eggs and larvae from the liquid when the basin is drained by opening the

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PCT/CA2012/001119 valve. The liquid passing through the filter is collected in a reservoir, from which filtered liquid may be returned to the basin by a pump, to refill the basin.

As will be described in greater detail below, the apparatus preferably is configured so that it may be positioned on a variety of standard containers, such as a typical 5-gallon bucket, for example. The container then acts as the reservoir. This ability to use readily available containers greatly enhances portability of the apparatus, and facilitates shipping for use in remote locations, since it may not be necessary to ship a container if standard containers are available at the destination.

Preferably, one or more attractant means are employed, as described in greater detail below. These may include, for example, various chemical attractants and light, as well as natural attractants, including the natural chemical cues released in the hatching process.

As part of the process of filtering and cycling filtered liquid back to the basin, the natural attractants and any added chemical attractants will gradually concentrate in the reservoir. It is an advantage of a particularly preferred embodiment that these attractants may be released from the reservoir, for example by vents near an upper portion of the basin, preferably in a controlled manner by being able to open or close the vents as desired, and preferably but not necessarily augmented by a fan to draw or blow air from the reservoir.

Preferably, the pump is integrated with the basin and drain as a unitary trap assembly, with a replaceable filter securable below the drain. Optionally, two or more units may have their reservoirs connected to each other, or may share a common reservoir. This has certain advantages as explained in greater detail below.

According to the method of the invention, the basin is filled with liquid, preferably with one or more attractant means being employed, and the liquid remains in the basin for a period of time for eggs and larvae to accumulate, but not long enough to mature. The basin is then drained through the filter into the reservoir. The basin is then refilled from the reservoir and the cycle begins again.

Optionally, the apparatus may be automated, and the method may be carried out automatically with only periodic maintenance.

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Further features of the invention will be described or will become apparent in the course of the following detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features, aspects and advantages of the invention will become better 5 understood with regard to the following description and accompanying drawings wherein:

Fig. 1 is an upper perspective view of the trap assembly, showing a container and cover in dotted lines;

Fig. 2 is a lower perspective view of the trap assembly;

Fig. 3 is a cut-away perspective view of the trap assembly and a container;

Fig. 4 is a cross-sectional view of the trap assembly and container;

Figs. 5A-5D are top views of the basin of the trap assembly, showing some rinsing variations;

Fig. 6 is a lower perspective view of the trap assembly, showing a filter aligned for installation;

Fig. 7 is a cross-sectional view of the trap assembly, showing the filter locked in position;

Fig. 8 is a cut-away perspective view of a ring which permits different-sized containers to be used;

Fig. 9 is a lower perspective view, showing a slider which can be used to close vents;

Fig. 10 is a perspective view of a custom container, showing a swing-open door to access the filter for maintenance or replacement;

Fig. 11 is a perspective view showing two units with their reservoirs shared;

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Figs. 12A-12C are various view showing an alternative trap assembly and container combination;

Fig. 13 is a flowchart showing an example of the control logic for an automated version of the system; and

Fig. 14 is a schematic illustration of a system with multiple units and a common filter, reservoir and pump.

DETAILED DESCRIPTION

The following description is of preferred and alternative embodiments by way of example only. Many variations on the specific structures and methods described below may be realized by those knowledgeable in the field of the invention, without departing from the scope of the invention and the claims which define the invention, regardless of whether or not such variations are expressly described.

For convenience and clarity, the invention will be described with reference to mosquitoes, but it should be understood that the apparatus and method will be suitable for many other insects that lay their eggs in aquatic locations, including for example blackflies, dragonflies and water scorpions, naming only a few.

Referring first to Figs. 1 to 7, a preferred embodiment of the apparatus 1 includes a trap assembly 1 having a drainable basin 2 positionable over a reservoir 3, the reservoir preferably being provided by a container 4. At the bottom of the basin is a drain assembly 5, having a drain opening 6 (see Fig. 3) and suitable means for opening and closing the drain opening, such as a gate or “knife” valve 7 (see Fig. 4). From the drain opening, water in the basin can be drained into and through a filter 8 and thence into the reservoir, by opening the gate valve, for example by an operating handle 9 connected to the gate valve by a cable 10, or by any other suitable means, the actual means by which the valve is operated not being critical. The filter captures any unwanted debris and targeted insect eggs and larvae from the water and allows the water and artificial or natural attractants in the water to pass into the reservoir.

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Although any suitable valve could be used, a gate valve is especially advantageous due to its self-cleaning nature, i.e. any debris or algae buildup is scraped off the gate each time the gate slides open.

Above the basin 2 is a cover 11 (see Fig. 2) to provide protection against excessive debris as 5 well as from wind, rain and sun. The cover has large lateral openings for mosquitoes to enter from the side.

The water level in the reservoir 3 is maintained below the height of the filter, so that the filter can dry out between times when the basin 2 is drained. Although the environment will be very humid, it will be sufficiently dry that the larvae cannot survive.

The specific filter to be used may vary widely, and could be as simple as the pleated type commonly used with swimming pools for example. The filter must allow water to pass freely into the reservoir, but must have pore sizes sufficiently small to trap the insect eggs and larvae while allowing passage of the water and any natural or synthetic attractant present in the water. The filter design preferably does not permit pooling of water at the bottom of the filter housing, so that maturation of the larvae cannot occur there. The filter may be secured by any number of conventional means, such as by positioning it against the drain assembly and rotating it so that the tongue 80 engages studs 81 (see Figs. 6 and 7).

The basin 2 can accommodate any suitable liquid that will attract gravid insects to lay their eggs in the liquid. In almost all cases, the liquid will be water, preferably supplemented with a chemical attractant or natural chemical cues that attract gravid insects. For convenience and clarity, the word “water” is used above and will be used below, but it should be understood that this includes water supplemented with attractants, as well as any other suitable liquids, unless the context indicates otherwise. Juices and other extracts or certain water-based solutions could conceivably be used, for example.

The inner surface of the basin 2 is typically concave in shape. However, the shape of the basin may be varied widely, according to design preference, though its inner surface of the basin should slope towards the drain assembly 5 to facilitate complete draining of the basin when the gate valve 7 is opened. Preferably, the inner surface should also be as smooth as

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PCT/CA2012/001119 possible so that eggs and debris do not adhere to it and so that the basin will drain as thoroughly as possible.

If desired, the apparatus may be supplied with a customized container to act as the reservoir 3. However, advantageously, the trap assembly 1 may be dimensioned to fit over a standard container 4, such as a typical 5-gallon bucket or pail. This avoids the need for a customized container and facilitates portability and shipment of the apparatus. It is then sufficient to supply the trap assembly without a container, as long as the purchaser or user has access to a 5-gallon pail or other suitable standardized container to act as the reservoir. In some situations, it may not even be necessary to provide a container. For example, in some situations the reservoir could be in the form of a suitably sized hole in the ground, lined with plastic to prevent leakage, though this may be far from an ideal configuration. In other situations, the reservoir function could be provided by a container which is not beneath the basin 2, but instead is merely connected by suitable tubing. It is also possible that a container or containment device could be made by local artisans using locally available materials such as brick or stone, mortar, etc..

In one embodiment, as best seen in Fig. 3, a ring 12 as shown in Fig. 8 can be provided around the upper periphery of the trap assembly 1 or basin 2, the ring having several concentric channels 13 of various diameters, to accommodate a variety of different container sizes. The ring may be formed integrally with the trap assembly or basin, or it may be provided as a separate item which may or may not be permanently secured in place. If desired, the ring may be provided with an optional gasket (not illustrated) to create an airtight seal between the trap assembly and the container, and/or there could also be a mechanical latch, tab, or other mechanism to create an airtight seal if desired, such as the latch 70 seen in Fig. 10. In some instances, the ring or a modified version thereof could be placed over a hole or pit dug in the ground or a projection raised from the ground and the trap assembly could then be positioned over the ring. This arrangement is suited to remote installations where containers may not be readily accessible.

For convenience, the trap assembly may be provided with a lifting handle 14 (see Fig. 1) to facilitate lifting the trap assembly 1 from the reservoir 3.

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The shape, size and colour of the basin 2 may be chosen to assist in attracting an insect to the pool to lay its eggs. For example, it is believed that mosquitoes prefer dark environments to lay their eggs. Accordingly, it may be preferable that the basin be produced in a dark and opaque colour. A dark colour basin would also retain heat, which has also been shown to be an attractant for mosquitoes and other flying insects. If the basin is opaque it may be beneficial to provide a transparent strip down the side of the basin, so that the water level in the reservoir 3 can be visually monitored. Alternatively, or in addition, it may be desirable to provide a translucent or transparent viewport 16 in any customized container 4, as a means of checking the water level.

The trap assembly also includes a pump 20 which extends down below the level of the filter (which is kept dry as much as possible) into the reservoir 3 to draw water therefrom. The pump may be of any desired form, manual or powered. For example, it can be of the common manual bilge pump variety as illustrated, operated by a pump handle 21, to pump water from the reservoir into the basin 2, or if powered, it could be a submersible 9-volt DC pump, for example. The pump has at least one outlet 22, which may be on the body of the pump itself, but preferably it is plumbed to several outlets 22 so that the inner surface of the basin can be thoroughly rinsed via swirling action. The several outlets 22 can be in any desired location or configuration to effectively rinse the basin, various examples being shown in Figs. 5A to 5D. As an alternative to a pump, a compressor or the like could conceivably be used in order to convey the water via differential air pressure within the container. In operation, the basin 2 is filled with water to a suitable level, which may be varied as desired according to the different breeding habits and preferences of the various insects that may use the basin as an artificial breeding pool to lay their eggs. Periodically, the gate valve 7 is opened to drain the basin through the filter 8, thereby capturing any eggs which have been laid on the water surface in the basin. The pump 20 is then operated to rinse the basin thoroughly, to wash any eggs or other debris from the basin down into the filter. After this rinsing has taken place, the gate valve 7 is operated to close the drain, and the pump is operated to refill the basin to the desired level.

With no attractants, some mosquitoes may choose the water in the basin as their breeding location. However, the performance of the apparatus is very significantly enhanced by employing means to specifically attract the mosquitoes. Several means may be used to attract the mosquitoes, either separately or preferably in combination.

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For example, the water in the basin 2 and/or in the reservoir 3 may be spiked with a liquid chemical attractant, such as those described in US Patent Publication No. 2008/0003197, which acts as chemical cue for gravid insects to lay their eggs in the water.

Another alternative uses a floating assembly 25 in the basin, as seen in Figs. 1, 3 and 4. As best seen in Fig. 3 this assembly includes a lower compartment filled with Styrofoam™ or the like (or air) sufficient for the assembly to float on the surface of the water. The assembly also has an upper compartment, with a hinged lid. The assembly is connected to a track 26 via a U-bar 27, which can slide up and down in the track according to the water level in the basin. A replaceable puck of attractant material can be placed in the upper compartment, to gradually exude attractants over an extended period of time from openings which could be along the top as shown in Fig. 3, or partially along the top, or from open ports near opposite ends of the assembly. Alternatively, or in addition, a slow-dissolving attractant composition could be deposited in the water in puck form, or in a tea-bag-like dispenser, whether in the basin 2 or in the reservoir 3.

A particularly advantageous attraction involves chemical cues which are released from the floating assembly into the water of the reservoir, in combination with natural chemical cues, such as pheromones naturally released by the mosquitoes when they breed successfully. These volatile natural chemical cues accumulate in the reservoir when the water is drained from the basin, since they form part of the aqueous phase within the container. Periodically releasing these pheromones from the reservoir can act as powerful mosquito attractants.

To facilitate this release, the upper edge of the basin 2 is preferably provided with a number of vents 30, as best seen in Figs. 1, 3, 6 and 9, which are open into the reservoir. The reservoir otherwise is preferably sealed, so that air can escape only via the vents. Preferably the vents are openable and closable, so that they may be opened only at peak hours, rather than “wasting” the pheromones in daytime or windy conditions. As shown in Fig. 9, for example, a shutter mechanism such as a slider 31 may be positioned behind the vents 30, configured such that moving the slider blocks or uncovers the vents. As one alternative, the slider could have apertures which either align with the vents, or block them, depending on the position of the slider. The slider could be manually operated, or for automated versions, a small motor 32 may be used to operate it, powered by the battery pack 33.

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Each successive cycle of draining the basin through the filter and then replenishing from the reservoir increases the concentration of attractants in the water, both natural and synthetic. More water may need to be added from time to time if the concentration of attractants becomes excessive, or if the water level drops due to evaporation.

As best seen in Figs. 3 and 9, a small fan 35 may be provided, preferably but not necessarily mounted to the trap assembly 1 rather than the container, and preferably but not necessarily near the vents 30, to assist in forcing the gas through the vents 30. This fan will also assist in the drying of the filter after the water has been passed through, to increase the efficiency of the system. Preferably the fan should be timed to operate only when peak attraction is desired, rather than continuously, since continuous operation would significantly reduce the attractant effect, as well as potentially producing excessive evaporation of the water in the reservoir 3 and draining the battery if battery powered.

Alternatively, in order to facilitate the release of the accumulated gas from the container, the container may be slightly pressurized prior to the opening of the vents 30, using a compressor or other means, provided that the container is airtight or relatively so.

To prevent the release of any mosquitoes that may have escaped filtration and hatched from the medium collected in the container, a screen may be provided above the waterline of the container with a mesh size capable of preventing the passage of mosquitoes. However, in general it will be difficult or impossible for such mosquitoes to escape from the container in any event.

Another attracting means is to use light emitting and/or light reflecting sources in the vicinity of the basin, such as light from a light or light pack 34 (see Figs. 1 and 4). These light sources may be in a single or multiple frequency arrangements, in accordance with known criteria for the target insect. Yet another attracting means is to place a filter in front of the light source, so as to create polarized light. In order to minimize the energy requirements of the apparatus, light emitting diodes (FEDs) are preferred as the light emitting source due to their low power consumption. However, any type of light emitting source shown to attract gravid insects will work with the apparatus. Similarly, any number of light reflecting sources can be used with the apparatus, including, but not limited to, reflective foils and the like, in order to reflect

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PCT/CA2012/001119 both ambient light sources, such as the moon or sky, or internal sources. Fig. 3 shows the use of reflective strips 32, for example.

Power for the fan and/or LEDs may be supplied from a battery pack 33 (see Fig. 9), preferably rechargeable, from plugging into a power source if available, or ideally from a battery pack recharged by a small solar panel suitably positioned outside the apparatus, whether secured thereto or as a separate component.

Another possible variation, to further enhance the effectiveness of the apparatus in attracting gravid insects which prefer not to lay their eggs directly on a water surface, is to provide an upper portion of the basin 2, and/or at least a portion of the upper surface of the floating unit 25, with an egg laying medium, such as germination paper 36 (see Fig. 3) or any other porous material that can hold humidity. Preferably the germination paper is positioned so as to have a portion which contacts the water in the basin, so that water wicks to keep the germination paper moist. The germination paper may be rinsed thoroughly by water from the outlets 22 from the pump 20, or may be suitably disposed of from time to time, weekly for example, or destroyed, for example by burning.

To assist in the evaporation of the water in the container, it may be desirable to construct the container from a material with a low albedo value, which will more rapidly heat up the water compared to light coloured material. This may be especially desirable in cooler locations, to create a warmer, moist environment to appeal to the mosquitoes.

To clean or replace the filter 8, it is advantageous to provide a customized container 4 with an access door, for example a swing-out door 40 as shown in Fig. 10. The filter may rest on a platform 41 extending inwardly from the door, such that swinging the door inwardly moves the filter into its proper operating position against a flange below the drain assembly 5 and drain opening 6.

Another possible variation is to connect multiple units to each other. It has been found that in installation with multiple spaced-apart units, some of the units become more effective at attracting gravid insects than other units, likely due to varying attractant levels in the water of the respective basins 2 and reservoirs 3. However, if the containers are interconnected so that the filtered water from each of the units can mix together, the overall effectiveness of all the

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PCT/CA2012/001119 units in the area at attracting gravid insects improves. Therefore, a system of interconnected units can be provided to enhance the ability restrict the maturation of aquatically hatched insects over a geographic area. This is illustrated in Fig. 11, showing just two units as an example. The reservoirs are connected via a hose 50 attached to connectors 51. A pump (not shown) can be connected to circulate the water between the multiple reservoirs periodically, either by manual operation, or under electronic control.

If several of the units are connected in an area, the system may be easier to monitor and maintain, and the attractant solution can be kept homogeneous among all the units, thus enhancing performance across the system.

It should be understood that many units could be connected together, and distributed over a wide area. Such arrangements have been found to be effective in reducing mosquito populations over a wide area. Each unit could have its own reservoir, with a pumping system circulating the water through the various connected units, or as shown in Fig. 14 there could be one or more central reservoirs 3 to which water from the various basins 2 is routed after passing through the valve assemblies 5 and their valves. The filtration could take place at each unit, or as shown in Fig. 14, there could be a centralized filter 8 instead.

Also, in regions where fresh water is difficult to obtain, one container placed in a cool area will most certainly augment the value of the use of this system, i.e. there can be a common reservoir in a cool area for a number of units, not associated with any one unit in particular but interconnected with all of the units.

Figs. 12A to 12C show an alternative configuration for the apparatus, in this embodiment, a container 4 provides the reservoir, and the basin 3 is defined by a depression in an upper piece which mates with the container. As can be seen from Fig. 12C, this configuration can be nested to a fair degree to facilitate shipping and/or end of season storage. Of course for shipping, the filter 8 would normally be removed as well. This configuration also does not required a container that is as deep, since the basin does not sit down in the container as in the other embodiments. This reduced container size reduces mold costs, and in general is easier to handle.

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The various embodiments described above can be operated entirely manually. However, in some embodiments of this invention, it may be desirable to automate the process, by using electrically actuated components (pump, valve, fan, vents, etc.), an electronic controller and timer, and various sensors. In such embodiments, a user may set the trap once, and the electronic controller will actuate the system on a pre-programmed sequence, only requiring periodic maintenance to add water and/or attractant, and to clean or replace the filter.

The electronic control unit may be located anywhere, whether as part of the unit, or as a separate component connected to the unit, whether adjacent the unit or remote from it. As an example, Fig. 12A shows an electronic control unit 60 which is operatively connected to the various components, and which may be powered as mentioned previously, i.e. from a battery pack 33 (preferably solar rechargeable) or from a connected power source if available.

Fig. 13 shows details of one possible control logic. The main process, namely a daily cycle, is shown at the bottom of Fig. 13. A suitably mounted light sensor detects a low light level signalling dusk, whereupon the apertured slider 31 is actuated to open the vents 30, and the fan 35 is turned on, so that attractants from the container 4 are released. Once still lower light levels are detected, signalling night-time, then the vents are closed and the fan is turned off. This cycle repeats daily. As shown at the bottom right of the drawing, alternatively a 24-hour timer could be used instead of using light levels. The timer could be a manually or electronically programmable timer to account for seasonal or geographical variations, such as in the extreme north where mosquitoes may be very abundant but it may not get sufficiently dark in summer.

A weekly cycle is also shown in Fig. 13 immediately above the daily cycle. In the weekly cycle, the gate valve 7 is first opened, to drain the basin 2 into the filter 8. After allowing sufficient time for the basin to drain, the pump 20 is operated to flush the inner surface of the basin, to ensure that larvae and eggs are washed down into the filter. The pump may then stop to allow full drainage before the gate valve is operated to close the drain, or it could continue to pump as the gate valve is closed. With the gate valve closed, the pump is operated to refill the basin to the desired level, either as detected by another sensor, or as determined by time if the pump operates at a fixed volumetric rate.

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Preferably, as shown in Fig. 13, a water level sensor in the reservoir 3 detects if the water level has become too low due to evaporation, and if so, illuminates an FED indicating that maintenance is required, whereupon an operator can add water to the system. Of course this could be automated as well, so that the water level is automatically maintained at a desirable level.

Many additional variations may be apparent to those who are knowledgeable in the field of the invention. The invention is therefore not limited to the specific embodiments described above, but instead is defined by the claims which follow.

Throughout this specification and the claims which follow, unless the context requires otherwise, the word comprise, and variations such as comprises or comprising, will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.

The reference in this specification to any prior publication (or information derived from it), or to any matter which is known, is not, and should not be taken as an acknowledgment or admission or any form of suggestion that that prior publication (or information derived from it) or known matter forms part of the common general knowledge in the field of endeavour to which this specification relates.

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Claims

THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS:

1. A system for reducing populations of aquatically hatched mosquitoes, the system comprising:

a plurality of trap assemblies each comprising a basin for selectively retaining a liquid, the basin having a drain opening and a valve below said drain opening for selectively opening and closing said drain opening;

a filter connected to receive liquid from each said basin via respective drain opening or a filter securable to each basin to receive liquid from each basin via said drain opening;

said filter having openings sized sufficiently small to collect eggs and larvae of the mosquitoes and permit the passage of said liquid;

a reservoir to collect liquid passing through said filter, the filtered liquid from each of said basin mixed in the reservoir; and a pump to return liquid from said reservoir to each said basin.
2. A system according to claim 1, wherein said valves and said pump are controlled electronically, for automated operation of the system.
3. A system according to claim 1, wherein said pump is a manual pump, and said valves are gate valves.
4. A system according to any one of claims 1 to 3, wherein said filter has openings sized sufficiently small to collect debris and algae.
5. A system according to any one of claims 1 to 4, wherein each basin has a germination paper positioned in an upper portion.
6. A method for reducing populations of aquatically hatched mosquitoes, the method comprising the steps of:

a. providing a system according to any one of claims 1 to 5;

b. filling the basins with liquid;

c. leaving the liquid in the basins for a period of time sufficient for eggs and larvae of the insects to accumulate, but not long enough to mature;

d. then operating said valves to drain the basins and to pass the liquid thence through said filters into said reservoirs;

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e. then closing said valves and operating said pumps to refill said basins; and

f. repeating the preceding from step c.
7. A method according to claim 6, comprising the additional step of operating said pump to rinse said basins after step d. and before step e..
8. A method according to claim 6 or 7, wherein said valves and said pump are all controlled electronically, for automated operation.

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FIGURE 5a FIGURE 5b

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FIGURE 12a FIGURE 12b FIGURE 12c

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Z>

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FIGURE 14