Device and method for controlling mosquito larvae

Abstract

The present invention relates to a device for releasing an insecticide suitable for controlling mosquito larvae. The device comprises a reservoir containing a preparation of at least one insecticide having larvicidal properties, wherein the reservoir comprises an outlet for releasing the preparation of the at least one insecticide. The device further comprises a gas-generating cell configured to build up a pressure by means of gas generation, wherein the device is configured such that pressure built up by the gas-generating cell causes movement of the preparation of the at least one insecticide out of the outlet of the reservoir. The invention also relates to method for controlling mosquito larvae, in particular by releasing a preparation of at least one insecticide having larvicidal properties, using a device according to the present invention.

Description

TITLEDEVICE AND METHOD FOR CONTROLLING MOSQUITO LARVAEBACKGROUND

[0001] The Asian tiger mosquito (Aedes albopictus) is increasingly spreading in Europe and other regions of the world and is associated with numerous problems. There are various health risks because the tiger mosquito can act as a vector of various pathogens, including dengue, chikungunya, and Zika viruses. Although the risk of infection in Europe is currently still low, the likelihood of transmission is increasing due to the increasing number of infected travelers, higher summer temperatures, and the growing tiger mosquito population. The mosquito species has spread worldwide in the last 30 years. In Europe, it has been found mainly in Mediterranean countries since the 1990s but is also spreading northwards. In Germany, already established populations have been detected in several federal states. In Switzerland, too, populations have become firmly established, especially in Basel and Ticino.

[0002] The tiger mosquito is characterized by a high adaptability. Their eggs are resistant to desiccation, and the species can go into hibernation (diapause), which favors its spread in temperate climate zones. Tiger mosquitoes are known for their aggressive and persistent biting behavior. They also bite during the day and can cause severe skin reactions such as swelling and itchy, painful irritations. As an invasive species, the tiger mosquito can displace native species and disrupt the ecological balance. The fight against and control of the tiger mosquito as well as the treatment of possible diseases transmitted by it already require considerable financial expenditure. In order to counter these problems, preventive measures such as the elimination of breeding sites and the education of the population are of great importance. At the same time, continuous monitoring of the spread and possibledisease transmission is required. Even if suitable means are available for the environmentally friendly control of the mosquito - such as preparations of Bacillus thuringiensis israelensis (Bti) - the control itself is difficult and very labor-intensive. Currently, the relevant exposure sites - in particular drains, sludge collectors, gullies, rain barrels, cisterns, former (unused) slurry pits and other places with standing water - must be treated with larvicidal preparations at intervals of 7 to 14 days. The amount of work and the susceptibility to errors are considerable, as the number of exposure sites to be treated is very high. In a medium-sized city like Basel alone, the exposure sites in the public sector are already in the thousands, to which there are at least as many exposure sites in the private sector. The total number of exposure sites is expected to be in a range of at least 1 per 20 inhabitants, half of which are in the public sector.

[0003] Devices for automated release of insecticides have been described, for example in Stevenson J.C., et al. "Controlled release spatial repellent devices (CRDs) as novel tools against malaria transmission: a semi-field study in Macha, Zambia." Malaria Journal 17.1 (2018): 437, Bernier U et al. "Combined Experimental- Computational Approach for Spatial Protection Efficacy Assessment of Controlled Release Devices against Mosquitoes (Anopheles)", PLoS Negl Trop Dis. 2019 Mar. 11 ; 13(3), in Indian Patent No. 470910 (Application No. 4051 / DEL / 2014; ROTATE ANTI-LARVA DEVICE), or in French Patent No. 1 ,476,660 (Pulverisateur mobile pour liquides insecticides rendu entierement automatique par procede electronique). However, all these solutions can either not be operated independently of the power supply and / or are associated with high costs and high susceptibility to errors due to the use of electromechanical wear parts (e.g., motors). They are not suitable for wide area use with a high number of exposure sites without a power supply. Autonomous solutions suitable for broad-scale use with high reliability and moderate manufacturing and operating costs are currently not available.

[0004] The underlying problem of the invention is therefore the provision of a device and process suitable for broadscale use to control the tiger mosquito at moderate production and operating costs with high reliability and high operational and environmental safety. The present invention solves the existing problem by providing devices and methods that enable a reliable release of larvicidal insecticides.SUMMARY OF THE INVENTION

[0005] The invention relates to devices and methods in which an insecticide, preferably a biological larvicide, is released by pressure of a gas-generating cell, preferably a hydrogen-generating cell. Corresponding devices are familiar to the person skilled in the art from automatic lubrication devices, where they are used millions of times. The devices are cost-effective, can be produced in mass, and have a high degree of reliability due to the lack of mechanical wear parts. Due to the closed device structure (encapsulation), a high level of operational and environmental safety is ensured. The devices may be refillable and only need to be replaced every 1 to 2 years. In a preferred embodiment, the devices are equipped with a control system, in particular an electronic or a mechanical control system, that allows a defined amount of the insecticide to be released at a defined interval. In a preferred embodiment this interval corresponds to the propagation (life) cycle of the targeted mosquito. Preferred is a release every 5 to 30 days, in particular every 5 to 20 days, preferably every 7 to 14 days, more preferably every 10 to 14 days or every 7 to 10 days, for example every 7 or 8 days.

[0006] In particular, the invention may refer to a device for releasing an insecticide suitable for controlling mosquito larvae, wherein the device comprises: a reservoir containing a preparation of at least one insecticide having larvicidal properties, wherein the reservoir comprises an outlet for releasing the preparation of the at least one insecticide, and a gas-generating cell configured to build up a pressure, in particular within the device, by means of gas-generating (i.e. to generate gas to build up a pressure, in particular within the device), wherein the device is configured such that pressure built up by the gasgenerating cell causes movement of the preparation of the at least one insecticide out of the outlet of the reservoir.

[0007] Preferably, the device may comprise a barrel, in particular a substantially cylindrical barrel, and a piston arranged in the barrel in a sealing and slidable manner, i.e. sealingly and slidably, along a length axis of the barrel. The device is configured such that the piston is movable by pressure built up by the gas-generating cell so that the pressure-driven movement of the piston pushes the preparation of the at leastone insecticide out of the outlet of the reservoir. Advantageously, such a barrel-piston configuration, which is similar to a syringe-like fluid releasing devices, is particularly easy and cheap to manufacture, allowing an efficient pressure-driven push-out of the insecticide out of the outlet of the reservoir. As used herein with reference to the barrel, the term “substantially cylindrical” in particular refers to the shape of at least a portion of an inner volume of the barrel, in which the piston is arranged in a sealing and slidable arrangement, i.e. sealingly and slidably.

[0008] In order to realize a sealing and slidable arrangement of the piston in the barrel along its length axis, the piston may preferably comprise a sealing member, in particular an elastic sealing member, providing a seal between the piston and the barrel. Preferably, the sealing member is integrally formed with the rest of piston. For example, the sealing member of the piston may comprise or may be formed by one or more flexible or elastically deformable fins, or one or more elastically deformable contour ridges, extending around the outer circumference of the piston. Preferably, at least the surface of the outer circumference of the piston, in particular the entire surface of the piston or the entire piston itself, is made of a plastic, rubber, or another elastomer material. Likewise, the one or more flexible or elastically deformable fins, or the one or more elastically deformable contour ridges can be made of a plastic, rubber, or another elastomer material.

[0009] As such, the piston preferably divides at least a portion of an inner volume of the barrel into a preparation volume defining the reservoir (including the outlet) and a gas volume, in particular gas-tight gas volume, for receiving gas generatable by the gas-generating cell to build up pressure for moving the piston. During this pressure- driven movement of the piston, the gas volume increases while the preparation volume decreases, causing a pressure increase of the preparation in the preparation volume that pushes the preparation out of the outlet of the reservoir. At the same time, the gas pressure in the gas volume decreases as the gas volume increases (if the gas-generating rate cannot compensate the decreasing pressure).

[0010] Gas-generating cells offer the advantage that they are compact and can operate without an external gas or power supply. They generate the required pressure directly through the electrochemical reaction. For this reason, the gas-generating cells referred to herein may also be denoted as electrochemical gas-generating cellsCorresponding cells are known to the person skilled in the art and commercially available at low prices. Preferably, the device gas-generating cell may be a hydrogen generating cell, in particular an essentially mercury-free hydrogen generating cell. Further details and examples of such gas-generating cells are described further below.

[0011] The gas-generating cell may be configured to generate gas with an alternating or a constant gas-generating rate, wherein the alternating or the constant gas-generating rate preferably is adjustable. For example, the alternating or the constant gas-generating rate may be adjustable by an electrical control signal, in particular a control voltage applied to the gas-generating cell.

[0012] In general, the device may be configured to release the insecticide either continuously or discontinuously at defined, i.e. predetermined, (time) intervals, in particular intermittently, more particularly periodically.

[0013] For the discontinuous release, the device may comprise a control system that is configured to allow a defined amount of the insecticide to be released at defined (predetermined) intervals. The control system may be a mechanical control system or an electrical control system. Further details and examples of such mechanical and electrical control systems will be described further below.

[0014] As described in more detail below, the periods or intervals of the discontinuous release are preferably set so that they are shorter or equal to the reproduction cycle of the mosquito species to be controlled. Accordingly, the device, in particular the control system, may be configured to control discontinuous release, in particular intermittent release, more particularly periodic release, of the insecticide (in intervals of) every 5 to 30 days, in particular every 5 to 20 days, preferably every 7 to 14 days, more preferably every 10 to 14 days or every 7 to 10 days, for example every 7 or 8 days. Such values reflect typical reproduction cycles of mosquito species.

[0015] In case the device comprises an electrical control system for the release of the insecticide, the device, in particular the control system, may comprise a control unit for discontinuous release, in particular intermittent release, more particularly periodic release, of the insecticide, which may be or may comprise one of:(i) a timer that is configured to activate the gas-generating cell at predetermined time intervals, and(ii) a receiver for wirelessly transmitted signals by which the gas-generating cell is activated, in particular a receiver configured to receive wirelessly transmitted signals for activating the gas-generating cell.Additional details of such control units are described further below.

[0016] Mechanical, cost-effective solutions for discontinuous delivery at constant gas pressure, a mechanical control system as described herein, may include one of:(1 ) a mechanical tact valve (impact valve): A mechanical tact valve can be designed in such a way that it opens and closes periodically due to the gas pressure. This can be realized, for example, by a spring and a diaphragm or a piston that opens briefly when a certain pressure is reached and then closes again. The cycle repeats itself as long as the gas pressure is present.(2) a rotary valve or a camshaft: A rotary valve or camshaft moved by hand or by a simple mechanical drive (e.g. movement, weight, spring) can periodically open and close a passage for the gas. Such solutions have been known in technology for a long time and are very robust.(3) mechanical dropper: For liquids, a mechanical dropper can be used, which closes for a moment after each drop and then opens again by means of a float or a mechanical lock.(4) mechanical timer: A spring timer can open and close a valve at regular intervals. The mechanics are simple, durable and require no electronics.(5) diaphragm pump with check valve: A small, mechanically driven diaphragm pump (e.g. periodically operated by spring or weight) can pump material at intervals at constant gas pressure. The check valve ensures that the substance is only released in one direction.

[0017] In an especially preferred realization of a mechanical control system, the barrel may -in particular in or at an inner surface, more particularly in or at an innercircumferential surface, especially in or at an inner (circumferential) surface along which the piston is movable in a sliding and sealing manner - comprise a retarding structure that is configured to temporarily block or delay the pressure-driven movement of the piston in one or more (intermittent) retarding sections along the length axis of the barrel as long as the pressure built up by the gas-generating cell in the gas volume is below a pre-defined threshold range.

[0018] More specifically, the retarding structure may be configured such that it provides a profile of varying mechanical resistance to the movement of the piston along the length axis, in particular a sequence of (intermittent) retarding sections of increased mechanical resistance, wherein the mechanical resistance in the one or more retarding sections is chosen so as to temporarily block or delay the pressure- driven movement of the piston (in a respective retarding section) as long as the pressure built up by the gas-generating cell in the gas volume is below a pre-defined threshold range. In this configuration, no or essential no insecticide is pushed out of the outlet and thus released from the reservoir. Vice versa, when the pressure built up by the gas-generating cell in the gas volume is increased to reach or to be above the pre-defined threshold range, the pressure is able to exert an actuation force onto the piston that is sufficiently large to overcome the mechanical resistance in the respective retarding section, and thus to move the piston out of the retarding section further forward along the length axis of the barrel, thereby pushing insecticide out of the outlet of the reservoir. As described above, the forward movement of the piston causes an increase of the gas volume accompanied by a decrease of the pressure in the gas volume driving the forward movement of the piston. The gas-generating rate of the gas-generating cell, the distance between adjacent retarding sections (defining the increase of the gas volume) and the mechanical resistance in the retarding sections are preferably chosen such that when the piston reaches the next retarding section the decreasing pressure in the gas volume again is low enough so as to be unable to overcome the mechanical resistance provided by the next retarding section. As consequence, when reaching the next retarding section, the pressure-driven movement of the piston is again blocked or delayed until the pressure in the gas volume again increases (by additional gas being generated and released into the gas volume) so as to reach or exceed the pre-defined threshold range.

[0019] Accordingly, by providing a sequence of intermittent retarding sections of increased mechanical resistance, the retarding structure allows to realize discontinuous, in particular intermittent, more particularly periodic release of a defined amount of insecticide at defined, i.e. predetermined, (time) intervals, i.e. a bolus-like release of insecticide at defined (time) intervals. Thereby, the amount of insecticide of each bolus depends on and thus can be controlled by the distance between adjacent retarding sections, while the (time) intervals between subsequent bolus releases depends on and thus can be controlled by (inter alia) the gasgenerating rate of the gas-generating cell.

[0020] In particular, the retarding structure and the gas-generating rate of the gasgenerating cell may be configured so as to provide a discontinuous release, in particular intermittent release, more particularly periodic release, of the insecticide (in intervals of) every 5 to 30 days, in particular every 5 to 20 days, preferably every 7 to 14 days, more preferably every 10 to 14 days or every 7 to 10 days, for example every 7 or 8 days.

[0021] In particular, the retarding structure (as realization of a mechanical control system) allows to operate the gas-generating cell with a constant gas-generating rate and thus without the need for an active control of the gas-generating rate, especially without the need for an electronic control unit. Advantageously, this simplifies the construction and operation of the device significantly.

[0022] The mechanical control system, in particular, the function of the retarding structure, may be based - inter alia - on form-fit, more specifically a temporary form fit. For this, the retarding structure may comprise intermittent changes, in particular intermittent enlargements or intermittent diminutions, of an inner cross-section of the barrel along the length axis barrel in order to realize a sequence of intermittent retarding sections of increased mechanical resistance. That is, in the one or more retarding sections the retarding structure may comprises at least one enlargement and / or at least one diminution of the inner cross-section of the barrel. Such enlargements and / or diminutions of the inner cross-section of the barrel may be configured so as to provide a mechanical interreference or engagement structure which a corresponding interreference or engagement of the piston may temporally interfere or engage with and be retained by as long as the pressure built up by thegas-generating cell in the gas volume is below the pre-defined threshold range, and thus too low to overcome forces associated with the engagement. For example, such an interference or engagement structure may be provided by a recess or a protrusion, in particular a circumferential recess or a circumferential protrusion, such as a circumferential groove or a circumferential ridge at an inner surface of the barrel which an elastic protrusion at an outer circumference of the piston may temporarily interfere or engage with. The interference or engagement can be released if the pressure built up by the gas-generating cell in the gas volume reaches or exceeds the pre-defined threshold range so as to exert a motion-inducing force onto the piston that is sufficiently large to temporarily deform the elastic protrusion. This enables the protrusion to disengage from the recess or protrusion at an inner surface of the barrel, thus allowing the piston to further move forward.

[0023] Accordingly, the intermittent changes, in particular the intermittent enlargements or the intermittent diminutions of the inner cross-section of the barrel may be formed by a plurality of recesses or protrusions intermittently arranged along the length axis of the barrel at an inner surface of the barrel. Accordingly, in the one or more retarding sections the retarding structure may comprise at least one protrusion, in particular at least one circumferential protrusion, for example at least one ridge, in particular at least one circumferential ridge, arranged at an inner surface of the barrel so as to form a diminution of an inner cross-section of the barrel along its length axis. Likewise, the retarding structure may comprise in the one or more retarding sections at least one recess, in particular at least one circumferential recess, for example at least one groove, in particular at least one circumferential groove, arranged at an inner surface of the barrel so as to form an enlargement of an inner cross-section of the barrel along its length axis.

[0024] Preferably, a corresponding interreference or engagement structure of the piston which may temporally interfere or engage with the interreference or engagement structure of the barrel, such the above-described enlargements or diminutions of the inner cross-section of the barrel, may comprise or may be formed by one or more flexible or elastically deformable fins, or one or more elastically deformable contour ridges, extending around the outer circumference of the piston. Advantageously, the corresponding interreference or engagement structure of the piston least is formed by a sealing member of the piston, for example a sealingmember as described further above. That is, the sealing member may be configured to interact with the retarding structure in the one or more retarding sections to temporarily block or delay the pressure-driven movement of the piston.

[0025] Likewise, the mechanical control system, in particular the function of the retarding structure, may be based - inter alia - on friction. For this, the retarding structure may comprise intermittent changes in a material property of the inner surface of the barrel along its length axis, causing intermittent changes in friction between the barrel and the piston along the length axis of the barrel. Especially, a material property of the inner surface of the barrel in the one or more retarding sections may be chosen to provide increased friction between the barrel and the piston along the length axis of the barrel as compared to other sections along the length axis of the barrel. For example, the inner surface of the barrel in the one or more retarding sections may be roughened or may have an increased surface roughness, i.e. be rougher as compared to the inner surface at other sections along the length axis of the barrel. Likewise, the inner surface of the barrel in the one or more retarding sections may be formed by a different material than other sections along the length axis of the barrel which provides increased friction between the barrel and the piston.

[0026] The number of bolus releases may depend on and thus be determined by the number of retarding sections. Preferably, the retarding structure comprises at least 2, in particular at least 5, more particularly at least 10 retarding sections , wherein the retarding sections arranged intermittently, preferably at equal intervals, along the length axis of the barrel.

[0027] The retarding structure can be created in or at an inner surface of the barrel, in particular in or at an inner circumferential surface of the barrel, more particularly in or at an inner (circumferential) surface of the barrel along which the piston is movable in a sliding and sealing manner, during or after its manufacturing. For a creation during manufacturing, a thermoplastic polymer like polypropylene or polyethylene is melted and injected into molds to form the barrel, wherein the mold provides the form for the retarding structure. Alternatively, the retarding structure can be created after production of the barrel by using a lathe, rotating brush, or similardevices. In a preferred embodiment, the barrel is the barrel of a one-way medical syringe, or a variant thereof.

[0028] The device may further comprise an outlet valve, in particular an outlet check valve, at the outlet of the reservoir. Advantageously, this allows for preventing undesired release of insecticide from the reservoir, especially in cases where the insecticide is to be released discontinuously in intervals. Likewise, device may further comprise a spray nozzle and / or a deflection nozzle the outlet of the reservoir.

[0029] The release of insecticide of the insecticide may occur directly from the outlet of the reservoir into the environment of the device, e.g. to a specific exposure site. Alternatively, the insecticide may be first conveyed from the reservoir to a (remote) exposure site via a conveyor system, such as one or more tubings, supply lines or hoses, connected to the reservoir. For this, the device may a connector at the outlet of the reservoir, in particular a luer-lock connector or slip-tip connector. In addition, the device may further comprise a conveyor system, such as one or more tubings, supply lines or hoses, connected or connectable to the outlet of the reservoir for conveying the insecticide released from the reservoir to a (remote) exposure site.

[0030] The device may further comprise a moisture sensor configured to prevent release of the insecticide during rainfall. Advantageously, this helps to avoid premature leaching of the insecticide from the exposure sites due to prolonged rainfall. As soon as the rain stopped and the surface of the device has dried again, the dispensing continues. Preferably, the humidity sensor is mounted on a top side of the device.

[0031] The device may further comprise attachment means configured to attach the device at the underside of an object, in particular of a cover, such as covers of drains, sludge collectors, gullies, rain barrels, cisterns, former (unused) slurry pits and covers of other places with standing water. Such attachment means may comprise a hook, adhesive tape, a clamp, and / or a hook-and-loop fastener.

[0032] In order to ensure safe and reliable operation under wet conditions, the device may be splash water protected and / or rainwater protected, preferably waterproof. For example, the device may comprise a splash water protecting or rainwater protecting housing, in particular a waterproof housing.

[0033] The at least one insecticide having larvicidal properties contains at least one active substance, selected from the group consisting of:- toxins, spores or mixtures thereof of at least one Bacillus strain, preferably at least one Bacillus thuringiensis israelensis (Bti) strain,- pyrethrum or pyrethrum-like substances (also called pyrethroids);- essential oils, and- chemical insecticides.

[0034] Preferred essential oils are, for example, citronella, geraniol, lemongrass, peppermint, cedar oil, eugeno.

[0035] Preferred pyrethroids are, for example, metofluthrin, transfluthrin, allethrin, bifenthrin, cyhalothrin, lambda-cyhalothrin, cypermethrin, cyfluthrin, deltamethrin, etofenprox, fenvalerate, permethrin, phenothrin, prallethrin, resmethrin, tetramethrin, tralomethrin.

[0036] Preferred chemical insecticides are, for example, imidacloprid, heptachlor, methoxychlor, mirex, pentachlorphenol, organophosphate compounds like acephate, Azinphos-methyl, Bensulid, Chlorethoxyfos, Chlorpyrifos, Chlorpyriphos-methyl, Diazinon, Dichlorvos (DDVP), Dicrotophos, Dimethoat, Disulfoton, Ethoprop, Fenamiphos, Fenitrothion, Fenthion, Fosthiazat, Malathion, Methamidophos, Methidathion, Mevinphos, Monocrotophos, Naled, Omethoat, Oxydemeton-methyl, Parathion, Parathionmethyl, Phorat, Phosalone, Phosmet, Phostebupirim, Phoxim, Pirimiphosmethyl, Profenofos, Terbufos, Tetrachlorvinphos, Tributes, Trichlorfon; Carbamate wie wie Aldicarb, Bendiocarb, Carbofuran, Carbaryl, Dioxacarb, Fenobucarb, Fenoxycarb, Isoprocarb, Methomyl, 2-(1 - Methylpropyl)phenylmethylcarbamat; Neonicotinoide like Acetamiprid, Clothianidin, Imidacloprid, Nitenpyram, Nithiazin, Thiacloprid, Thiamethoxam .

[0037] Particularly advantageous are environmentally friendly biological agents Bacillus thuringiensis israelensis (Bti) strains, for example Bacillus thuringiensis israelensis (Bti) serotype H14 (preferably strain AM65-52). Bti strains produce toxins that are ingested by the mosquito larvae with their food and cause a specific, fatalintestinal disease. Bti is very specific against mosquito larvae. Phytotoxic effects are not known. The skilled person is familiar with how to determine the optimum amount of active substance in each case depending on the surface area and the water volume of the exposure site (Lai L et al. Bacillus thuringiensis Cyt Proteins as Enablers of Activity of Cry and Tpp Toxins against Aedes albopictus). Toxins (Basel). 2023 Mar 10; 15(3):211. doi: 10.3390 / toxinsl 5030211 ). According to Lai et al., the LC50 (median lethal concentration) is 178 ng / mL for Cry4Aa, 46 ng / mL for Cry4Ba, 228 ng / mL for Cry11Aa, and 171 ng / mL for CytlAa. These values indicate the concentration at which 50% of the larvae died.

[0038] For applications, it is best to follow the manufacturer's recommended dosage for commercial Bti products for tiger mosquito control. The form of application according to the invention does not require any special adjustments here. A target concentration of 10,000 ITU / I is usually sufficient.

[0039] Guidelines for adapting the dosage for the control of tiger mosquitos are well known to the person skilled in art and - among others - available from the German municipal action group to combat the mosquito plague («Kommunale Aktionsgemeinschaft zur Bekampfung der Schnakenplage e.V.»; at: https: / / www.kabsev.de / 1Z1_3 / 1_3_2 / 1_3_2_2 / index.php). Tiger mosquitoes but also the common house mosquito or northern house mosquito (Culex pipiens) belong to the family of Culucidae for which usually a dose of 0,2 ppm results in a 100% mortality rate.

[0040] In general, the preparation of the at least one insecticide to be released, in particular the insecticide, may be in the form of a powder, a paste, a pellet, a gel, a liquid or combination thereof.

[0041] In a preferred embodiment, the insecticide to be released is in the form of a powder, a paste, a pellet, a gel, a liquid or a combination thereof. Preferred are liquid or gel-like formulations (preparations). Suitable preparations are, for example, commercial Bti formulations such as VectoBac™ 12 AS (Valent BioSciences Corp.) or Aquabac™ XT (Andermatt Biocontrol Suisse AG, Stahlermatten 6,6146 Grossdietwil; Switzerland). Depending on the size of the application device and the area of exposure, the concentration of the active substance must be adjusted so that at least 30 doses (one dose per week for the period from April to October), preferably35 doses, can be released. When using the 125 ml Simalube™ unit, this would be doses of about 3.5 ml. The commercially available Bti preparations are usually diluted for this purpose. A pilot study for the respective forms of exposure (gully, dole, rain barrel) is useful in order to determine the most effective and economical concentrations for different scenarios.

[0042] The preparation of the at least one insecticide (herein also denoted as insecticidal preparation) may comprise one or more additives configured to enhance the stability, uniformity, and / or homogeneity of the preparation, such as one or more preservatives, emulgents, and / or dispersants (dispersing agents) etc..

[0043] As used herein, the term “stability” refers to the "half-life" of active ingredient. "Half-life" relates to the period of time which is needed to eliminate half of the activity, amount, or number of molecules. In the context of the present invention, the half-life of an active ingredient is indicative for the stability of said active ingredient. The half-life of an active ingredient is influenced by the presence of preservatives and stabilizers known to the person skilled in the art. As used herein, the terms “uniformity” and “homogeneity” refer to physical distribution or concentration of the active ingredient over the length of the barrel. Preferably, this distribution or concentration is essentially uniform and does not change over time, even if the active ingredient is not a solution but - for example - a dispersion.

[0044] Furthermore, the insecticidal preparation may comprise a surfactant, preferably an anionic surfactant, capable of lowering the surface tension of a liquid, e.g. water, in which the insecticidal preparation is to be released. As mosquito larvae have to adhere to the surface of the water reservoir to breathe, adding a surfactant reduces the surface tension and causes the larvae to sink to the bottom of the reservoir, where they cannot receive oxygen and die.

[0045] In a preferred embodiment, the device can be refilled with the preparation of the at least one insecticide at least once. Refilling is preferably done by a specialist.

[0046] According to another aspect of the invention, a method is provided for controlling mosquito larvae, in particular by releasing a preparation of at least one insecticide having larvicidal properties at one or more exposure sites, using a device according to the present invention and as described herein, wherein preferably aneffective, especially defined, amount of the at least one insecticide having larvicidal properties is released every 5 to 30 days, in particular every 5 to 20 days, more particularly every 7 to 14 days, especially every 10 to 14 days or every 7 to 10 days, for example every 7 or 8 days.

[0047] Preferably, the method is provided as a service to an area - preferably a city - covering at least 100, preferably at least 1000 exposure sites by fasten at least one device according to the invention to the majority, preferably all, of the exposure sites.

[0048] For this, the device preferably is attached to the underside of a cover, in particular a cover of a drain or a cover of a sludge collector, a cover of cistern or a cover of a rain barrel.

[0049] Preferably, the method is applied to an area with at least 100, preferably at least 1000 exposure sites.

[0050] Further features and advantages of the method have been described with respect to the device according to the present invention and as described herein, and equally apply.

[0051] According to yet another aspect, the present invention provides a system comprising at least 10, more preferred at least 100, most preferred at least 1000 exposure sites, wherein preferably at least 50%, more preferred at least 75%, most preferred at least 90% of the exposure sites are prepared with a device according to any one of claim 1 to 27.

[0052] According to a further aspect, the present invention relates to a barrel for use in a device according to the present invention and as described herein, wherein the barrel comprises at an inner surface a retarding structure in a plurality of retarding sections along a length axis of the barrel, wherein the retarding structure is configured to temporarily block or delay a pressure-driven movement of a piston at said retarding sections along the length axis of the barrel as long as the pressure is below a predefined threshold range.

[0053] The retarding structure may provide a profile of varying mechanical resistance to the movement of the piston along the length axis, wherein themechanical resistance in the one or more retarding sections is chosen to temporarily block or delay the pressure-driven movement of the piston as long as the pressure built up by the gas-generating cell in the gas volume is below a pre-defined threshold range.

[0054] In one or more retarding sections the retarding structure may comprise at least one enlargement and / or at least one diminution of an inner cross-section of the barrel.

[0055] In the one or more retarding sections the retarding structure may comprise at least one protrusion, in particular at least one circumferential protrusion, for example at least one ridge, in particular at least one circumferential ridge, arranged at an inner surface of the barrel, the at least one protrusion preferably creating a diminution of an inner cross-section of the barrel along its length axis.

[0056] In the one or more retarding sections the retarding structure comprises at least one recess, in particular at least one circumferential recess, for example at least one groove, in particular at least one circumferential groove, arranged at an inner surface of the barrel, the at least one recess preferably creating an enlargement of an inner cross-section of the barrel along its length axis.

[0057] In the one or more retarding sections a material property of the inner surface of the barrel is chosen to provide increased friction between the barrel and the piston along the length axis of the barrel as compared to other sections along the length axis of the barrel. In particular, the inner surface of the barrel in the one or more retarding sections may be roughened or may have an increased surface roughness (as compared to other sections along the length axis of the barrel) to provide increased friction between the barrel and the piston along the length axis of the barrel as compared to other sections along the length axis of the barrel.

[0058] The barrel may comprise at least 2, in particular at least 5, more particularly at least 10 retarding sections, wherein the retarding sections arranged intermittently, preferably at equal intervals, along the length axis of the barrel.

[0059] According to a further aspect, the present invention relates to a device comprising:- a barrel according to afore mentioned aspect of the present invention and as described herein,- a piston arranged in the barrel in a sealing and sliding manner, wherein the piston divides at least a portion of an inner volume of the barrel into a preparation volume and a gas volume, in particular gas-tight gas volume,- a gas-generating cell at a first end of the barrel which is configured to build up a pressure in the gas volume by means of gas generation,- an outlet from the preparation volume at a second end of the barrel, wherein the device is configured such that pressure built up by the gas-generating cell causes movement of the piston towards the outlet.

[0060] The piston may comprise a sealing member, in particular an elastic sealing member, providing a seal between the piston and the barrel.

[0061] The device may further comprise a treatment composition contained in the reservoir volume between the piston and the outlet, wherein the device is configured such that pressure built up by the gas-generating cell causes movement of the treatment preparation out of the outlet of the reservoir.

[0062] The treatment preparation may be a composition suitable for at least one application selected from the group consisting of:- pharmaceuticals and drug delivery use,- agriculture use, preferably fertilizer or crop protection use,- pest control use,- cosmetics use,- industrial and environmental applications, and- veterinary medicine and animal care.

[0063] Such barrels and devices are useful for all applications, where a periodic release of composition is required and where costs should be kept at a minimum i.e., without the need for electronic control. Applications that would benefit from periodic (or controlled) release of a composition or active ingredient are typically those where sustained efficacy, reduced side effects, or improved compliance are critical. Such applications may include (1 ) pharmaceuticals and drug delivery (e.g., to maintain thetherapeutic levels of a drug over time without frequent dosing), (2) agriculture (e.g., to reduce the need for repeated application of pesticides, fertilizers, or herbicides). A controlled release of fertilizers improves nutrient availability and reduces runoff. A gradual release of pesticides or insecticides can provide season-long protection. A periodic release of herbicides prevents regrowth without harming crops or needing reapplication. (3) Cosmetics, personal and home care (e.g., to enhance effectiveness and user convenience. For example, periodic release of fragrances to achieve long- lasting scent). (4) Industrial and environmental applications (e.g., to reduce maintenance, improve safety or efficiency). For examples: Corrosion inhibitors, water treatment chemicals (e.g., for pools or industrial systems). (5) Veterinary medicine and animal care (e.g., periodic release of nutrients, per control agents etc.).

[0064] The invention is defined in the claims. However, below there is provided a non-exhaustive list of non-limiting exemplary embodiments. Any one or more of the features of these embodiments may be combined with any one or more features of another example, embodiment, or aspect described herein.Embodiment 1 : Device for the release of an insecticide suitable for the control of mosquito larvae, comprising a container containing a preparation of at least one insecticide with larvicidal properties, wherein the insecticide with larvicidal properties is released by pressure from a gas-generating cell.Embodiment 2: The device according to Embodiment 1 , wherein the gasgenerating cell is a hydrogen generating cell, preferably an essentially mercury -free hydrogen generation cell.Embodiment 3. The device according to Embodiment 1 or 2, wherein the apparatus comprises a control unit for the periodic release of the insecticide, which is selected from the group consisting of:(i) a timer that activates the gas-generating cell at predetermined time intervals, and(ii) a receiver for wirelessly transmitted signals by which the guest winding cell is activated.Embodiment 4: The device according to Embodiment 3, wherein periodic release is every 7 to 14 days.Embodiment 5: The device according to any one of Embodiments 1 to 4, wherein the device comprises a moisture sensor which prevents the insecticide from being released during rainfall.Embodiment 6: The device according to any one of Embodiment s 1 to 5, wherein the device comprises attachment means which allows the device to be attached to the underside of covers.Embodiment ?: The device according to any one of Embodiment 1 to 6, wherein the device is at least protected against splash water and rainwater, preferably watertight.Embodiment 8: The device according to any one of Embodiments 1 to 7, wherein the device does not contain any electromechanical, functionally relevant elements.Embodiment 9: The device according to any one of Embodiments 1 to 8, wherein the insecticide having larvicidal properties contains at least one active substance, selected from the group consisting of(i) toxins, spores or mixtures thereof of at least one Bacillus strain, preferably at least one Bacillus thuringiensis israelensis (Bti) strain,(ii) pyrethrum or pyrethrum-like substances (called pyrethroids)(iii) chemical insecticides.Embodiment 10: The device according to any one of Embodiments 1 to 9, wherein the insecticide to be released is in the form of a powder, paste, pellet, gel, liquid or combination thereof.Embodiment 11 : Use of a gas-generating cell for releasing insecticides or pesticides, preferably for periodically releasing insecticides with larvicidal properties.Embodiment 12: Use according to Embodiment 11 , wherein the gas-generating cell is a hydrogen generating cell, prefers a substantially mercury-free hydrogen generating cell.Embodiment 13: Use of an automatic lubrication device having a gasgenerating cell for releasing at least one insecticide or pesticide, wherein the lubrication device is filled with at least one insecticide or pesticide, preferably an insecticide with larvicidal properties, instead of lubricating oil.Embodiment 14: A method of controlling mosquito larvae using a device according to any one of Embodiments 1 to 10, wherein an effective amount of at least one insecticide having larvicidal properties is released every 7 to 14 days.Embodiment 15: The method of Embodiment 14, wherein the device is attached to the underside of covers or covers of drains, sludge collectors, cisterns or rain barrels.DESCRIPTION OF THE ILLUSTRATIONS

[0065] Aspects, embodiments and features disclosed herein are evident from the following detailed description when viewed in conjunction with the attached drawings.

[0066] Figure 1 (Fig.1 ): Shown is a schematic representation of the releasing device with the following components:100: housing (preferably made of metal, especially preferably with coating on the inside.101 : control unit102: socket or thread (optional)103: gas-generation cell104: expandable chamber (gas volume) for receiving the gas105: movable piston106: reservoir with the insecticide (preparation volume)107: valve (optional)108: outlet

[0067] Figure 2 (Fig. 2): Shown is a graphic drawing of the releasing device. The assignments to Figure 1 apply.

[0068] Figure 3 (Fig. 3): Shown is an example for attaching the releasing device to the underside of a cover. The assignments to Figure 1 and the following assignments apply:109: cover (e.g. of sludge catcher, drain, gully or rain barrel)110: openings in the cover (optional; especially for sludge traps, drains or gullies)111 : attachment means (e.g. magnet, clip or adhesive tape)

[0069] Figure 4 (Fig. 4): Figure 4: Shown is a typical dole as used for rainwater runoff in Switzerland. The following assignments apply:400: cover of a drain (manhole cover)401 : inlet402: drain403: water404: drain pit405: soil406: device for releasing active substances (especially larvicides)

[0070] Figure 5 (Fig. 5): a. cross-sectional drawing of a sludge collector (drain I gully) according to the German system with sludge bucket b. illustration of the active substance distribution at two sources of exposure (exposure sites)500: Device for releasing active substances501 : Outlet / supply line (hose) to lower water reservoir502: Outlet / supply line (hose) to the upper water reservoir503: Lower water reservoir (base of drain)504: Upper water reservoir (sludge bucket)

[0071] Figure 6 (Fig. 6): Shown is another example for attaching the releasing device to the underside of a cover. The assignments to Figure 1 and 3 and the following assignments apply:112: humidity / rain gauge113: deflection nozzle

[0072] Figure 7 (Fig. 7): Photo of mosquito larvae after sampling.A: in a petri dishB: detail - solitary larva

[0073] Figure 8 (Fig. 8): Schematic representation of a gas-generating cell. The assignments to Figure 1 apply.

[0074] Figure 9 (Fig. 9):A: typical drain cover / gully cover to the underside of which the device is to be attachedB: sludge collector (public roads and paths), Swiss system without sludge bucket.

[0075] C: drain cover (private land, transition of roof drainage / rain pipe to public sewer), Swiss system without leaf collector. Figure 10 (Fig. 10): Schematic illustration of device having a mechanical control system for intermittent (periodic) release of a larvicidal insecticide:10-1 : piston with flexible plastic fins10-2: preparation volume defining reservoir containing preparation of at least one insecticide having larvicidal properties10-3: gas volume for receiving gas generatable by the gas-generating cell10-4: gas-generation cell10-5: retarding structure (grooves) providing mechanical resistance to the movement of the piston10-6: outlet10-7: barrel

[0076] Figure 11 (Fig. 11 ): Schematic illustration of a device having a mechanical control system for intermittent (periodic) release of a larvicidal insecticide:11 -1 : piston made of an elastomer (e.g., rubber)11 -2: preparation volume defining reservoir containing preparation of the at least one insecticide having larvicidal properties11 -3: gas volume for receiving gas generatable by the gas-generating cell11 -4: gas-generation cell11 -5: retarding structure (grooves) providing mechanical resistance to the movement of the piston11 -6: outlet11 -7: barrel

[0077] Figure 12 (Fig. 12): Schematic illustration of a device having a piston with an O-ring12-1 : piston12-2: preparation volume defining reservoir containing preparation of the at least one insecticide having larvicidal properties12-3: gas volume for receiving gas generatable by the gas-generating cell12-4: O-ring12-5: retarding structure (grooves) providing mechanical resistance to the movement of the piston due to interference with O-ring forming a deformable protrusion12-7: barrel

[0078] Figure 13 (Fig. 13): Schematic drawing of the releasing device:13-1 : piston with flexible plastic fins13-2: preparation volume defining reservoir containing preparation of at least one insecticide having larvicidal properties13-3: gas volume for receiving gas generatable by the gas-generating cell13-4: barrel13-5: retarding structure (surface sections with increased surface roughness) providing mechanical resistance to the movement of the piston

[0079] Figure 14 (Fig. 14): Example of a circuit diagram of an electronic microcontroller for discontinuous release of insecticides:14-1 : battery14-2: microcontroller14-3: MOSFET14-4: resistor (preferably variable resistor, potentiometer)14-5: gas-generating cell

[0080] Figure 15 (Fig. 15): Example for attaching the device according to the invention to an object using attachment means:A: Schematic drawing of attachment means15-1 : U-shaped attachment means made from spring steel15-2: cord15-3: folding wingsB: Schematic drawing of positioning the attachment means(I) cover for drain without device(II) cover for drain with device during positioning(III) cover for drain after positioning, preventing removal(IV) removal of device using a removing tool with a magnet for disengaging folding wings15-4: removing tool15-5: magnet

[0081] Figure 16 (Fig. 16): One-way syringe equipped with a gas-generating cell to provide a low-cost embodiment of the device according to the invention.800: barrel801 : control unit802: clamps803: gas-generation cell804: gas volume805: piston806: reparation volume

[0082] 807: outlet Figure 17 (Fig. 17): Schematic illustration of different embodiments for the barrel of a device having a mechanical control system for intermittent (periodic) release of an insecticide:Variant A: Barrel with intermittent enlargements of the inner cross-section of the barrel (formed by circumferential recesses, e.g. grooves in the inner surface of the barrel)17-1 : recesses (grooves)Variant B: Barrel with intermittent diminutions of the inner cross-section of the barrel (formed by circumferential ridges at the inner surface of the barrel)17-2: protrusions (ridges)Variant C: Barrel with of intermittent combination of recesses (grooves) and protrusions (ridges)17-3: combination of recesses (grooves) and protrusions (ridges)DEFINITIONS

[0083] Unless otherwise defined, all technical and scientific terms used herein shall have the same meaning as it is generally understood by a person having average skills in the field to which this invention belongs. The materials, methods and examples provided herein are for illustrative purposes only and are not to be construed in a restrictive manner.

[0084] The term "and / or" is to be understood as a specific disclosure of each of the two specified features or components, with or without the other. Therefore, the term "and / or" when used in a sentence such as "A and / or B" should include "A and B", "A or B", "A" (alone) and "B" (alone). Similarly, the term "and / or" when used in an expression such as "A, B and / or C" shall include any of the following embodiments: A, B and C; A, B or C; A or C; A or B; B or C; A and C; A and B; B and C; A (alone); B (alone); and C (alone).

[0085] The term "autonomous" means that a device can function independently of external sources of supply, such as a power supply.

[0086] The terms "comprising" and "including" mean that at least the features or components mentioned are present without excluding any additional unspecified features or components.

[0087] When a term is given in the singular, other embodiments described by the plural of that term are also provided. The term "a" or "an" is not to be interpreted as meaning that there is only a single element, but rather that at least one element is present.

[0088] "Anopheles" refers to the genus of mosquito species that transmits malaria, specifically the species Anopheles gambiae, Anopheles coluzzii and Anopheles stephensi.

[0089] The terms "about", "circa", "approximately" are used synonymously and, when referring to a measurable value such as a parameter, an amount, a duration of time and the like, mean any value with a variation of + / -10 % more or less, preferably + / -5 % more or less, more preferred + / - 1 % more or less and even more preferred + / - 0.1 % more or less of the specified value, provided that such variation appears reasonable to the skilled person in the context of the present invention. It is understood that the stated value to which the term "about", "circa" or "approximately" refers is itself specifically and preferably disclosed.

[0090] "Exposure site" means all places where mosquitoes, especially tiger mosquitoes, prefer to reproduce. These are usually places with standing water, preferably without direct sunlight. In the context of this invention, sludge collectors (gullies or drains) for surface water on roads and sidewalks or on rain pipes, as well as rain barrels and other rainwater collection containers such as cisterns and former (unused) slurry pits are preferred.

[0091] "Insecticide" or "insecticidal effect" are used interchangeably and mean to disrupt the harmful activity of an insect, including but not limited to killing the insect, inhibiting the growth or activity of the insect, inhibiting the insect's reproduction, changing the insect's behavior, or repelling the insect.

[0092] ITU (International Toxic Units) means the international measurement standard for bacterial larvicides (BL), mainly composed of Bacillus thuringiensis subsp. israelensis and Bacillus sphaericus products. The efficacy of a given bacterial larvicide (BL) product is determined per biopotency, comparing the mortality of mosquito larvae induced by the product being tested with the mortality induced by a corresponding reference standard (the results are reported as international toxic units (ITU) / mg product for products based on Bacillus thuringiensis subsp. israelensis (Bti) and the results as Bs ITU / mg for Bacillus based products sphaericus (Bs) according to WHOPES (WHO Pesticide Evaluation Scheme) guidelines.

[0093] "Larvicide", "larvicidal effect" and "larvicidal property" are used interchangeably and mean to interfere with the harmful activity of an insect at the developmental stage of the larva, including but not limited to killing the larva, inhibiting the growth or activity of the larva, changing the larva's behavior or repelling the larva.

[0094] "Mosquito" means all mosquitoes and mosquito species including but not limited to the common mosquito (Culex pipiens, one of the most common species in Germany and Switzerland), the grass mosquito (Culiseta annulata), the Asian tiger mosquito (Aedes albopictus), the flood mosquito (Aedes vexans), the black fly (Simuliidae), forest midges (e.g. Aedes cantans, A. punctor), midges (bearded gnats). There are about 3,500 different mosquito species worldwide, with about 100 species occurring in Europe. These mosquitoes can have different lifestyles and reproductive patterns, which affects their role as disease carriers.

[0095] "Tiger mosquito" means the species Aedes albopictus and all its subspecies.

[0096] “Release of / releasing the preparation of the at least one insecticide (having larvicidal properties)” and “release of / releasing the insecticide (having larvicidal properties)” are used interchangeably and mean to release the preparation of the at least one insecticide having larvicidal properties (in any form, such as in the form of a powder, a paste, a pellet, a gel, a liquid or a combination thereof) from the reservoir, in particular into the environment of the device, e.g. to a specific exposure site.

[0097] The term “enlargement” refers to an enlargement of the inner cross-section of the barrel, e.g. realized by a recess, in particular a groove, in the inner surface.Likewise, the term “diminution” refers to a diminution of the inner cross-section of the barrel, e.g. realized by a protrusion at the inner surface.DETAILED DESCRIPTION

[0098] A first aspect of the invention relates to a device for releasing an insecticide suitable for the control of mosquito larvae, comprising a container (reservoir) containing a preparation of at least one insecticide having larvicidal properties, wherein the insecticide is released by pressure from a gas-generating cell. The container (reservoir) for the insecticide with larvicidal properties is preferably replaceable or refillable.

[0099] The container (reservoir) for the insecticide has at least one outlet that allows it to be released to at least one exposure site. If the exposure area has more than one water reservoir, the device has a correspondingly higher number of outlets. For example, many drains and gullies have a sludge bucket for collecting leaves, etc., at the bottom of which a water reservoir can also form (see Figures 5a and 5b; https: / / de.wikipedia.org / wiki / Stra%C3%9Fenablauf). An additional reservoir is then located at the bottom of the drain or gully. In such a case, the outlet may be provided with one or more supply lines or hoses which ensure that the insecticidal active substance passes from the device of the invention to the exposure site.

[0100] The outlet can be equipped with other applications. For example, especially in liquid formulations, it is reasonable to provide a check valve that only opens under pressure and to prevent the active substance solution from seeping out between application intervals. Furthermore, the outlet may be equipped with a spray nozzle to allow for better distribution of the active substance in the exposure area. Likewise, the outlet may be equipped with a deflection nozzle as shown in Fig. 6.

[0101] The active substance is released by electrochemical gas-generating cells, which can be used to build up pressure. These are commercially available. Electrochemical gas-generating cells are used to build up pressure by means of gasgenerating and in this way to move the active substance in a self-actuating manner. In principle, any gas-generating cell can be used, with preference being given to hydrogen, oxygen or carbon dioxide-generating cells.

[0102] Gas-generating cells are known, for example, from the German disclosure DE 35 32 335 and the European patent application EP 1 396 899 A2. Other cells are described in GB 1178859, WO 99 / 63605, US 2008 / 226976, US 2004 / 229090, US 6 461 761 , US 4,948,684.

[0103] In a preferred embodiment, the gas-generating cell is a hydrogen generating cell, especially a substantially mercury-free hydrogen generating cell. In this process, hydrogen is produced in an electrochemical reaction, which builds up the pressure. In an electrochemical reaction at the anode, metallic zinc is oxidized in an alkaline electrolyte to a doubly positively charged zinc ion (Zn++) and the desired hydrogen gas is generated at the cathode by a reduction reaction from cations containing protons. These cells can be used in various areas where a controlled pressure build-up is required. Gas-generating cells offer the advantage that they are compact and can operate without an external gas supply. They generate the required pressure directly through the electrochemical reaction. Corresponding cells are known to the person skilled in the art and commercially available at low prices.

[0104] Mercury-free hydrogen-generating cells are preferred. Such cells are known to the person skilled in the art DE 502009009344 D1 describes, for example, a mercury-free hydrogen generating cell that has a metal anode, an electrolyte and a gas diffusion electrode, where the metal anode comprises zinc with additives of indium and bismuth as its main component and wherein the electrochemical gasgenerating cell, calculated on its total weight, contains less than 5 ppm for mercury, less than 20 ppm for cadmium and less than 40 ppm for lead. Other preferred cells are described, for example, in DE 202010016528 U1 , EP 2 337 124 B1 (electrochemical gas development cell, in particular mercury-free hydrogen development cell; SIMATEC AG), WO 2023227308 and DE 3532 335 C2. These cells are used in automatic lubrication devices for the continuous delivery of lubricants.

[0105] Other suitable hydrogen generating cells are available from VARTA Mikrobatterie. A single coin cell releases a total of 130 ml (more than 200 times the volume of the cell) of high-purity (99.99%, E949) H2 gas at a rate of up to 15 ml / h. The gas is generated by connecting a resistor to the cell, and the rate is proportional to the discharge current, inversely proportional to the resistance value. Varta's single cell (part #4690-101-501 ) has a wide operating temperature range and complies withEll Directive 2006 / 66 / EC. It measures 11 .55 mm in diameter x 5.45 mm and weighs only 1.85 g (see https: / / www.varta-ag.com / de / industrie / produktloesungen / gas for more information).

[0106] A further aspect of the invention therefore relates to the use of a gasgenerating cell for releasing, preferably for periodically releasing insecticides or (other) pesticides, preferably insecticides with larvicidal properties. The gasgenerating cell is preferably a hydrogen generating cell, preferably a hydrogen generating cell that is essentially mercury-free.

[0107] In a preferred embodiment, hydrogen pressure moves a movable piston (see e.g. piston 105 in Fig. 1 ) that is inserted into the container (reservoir) in a gastight manner. The movement of the piston pushes the insecticide out of the outlet. Corresponding devices are already being used for automatic lubrication (lubricant dispensers). In its particularly preferred embodiment, the device according to the invention is based on an empty lubricant dispenser (i.e. , provided without lubricant) operated with a hydrogen generating cell, preferably on a commercially available dispenser. Such devices are commercially available from various manufacturers. Examples include:(i) Simalube™ devices from Simatec AG(ii) The perma CLASSIC and perma FUTURA devices from perma-tec(iii)The SYSTEM 24 LAGD SKF from SKF(iv)The G-Mini lubrication system from GracoOther systems are available from Bijur Delimon (Pulsarlube) and Gruetzner GmbH (Lubricus series).

[0108] Automatic lubricator dispensers without lubricant filling, such as those available from Simatec (simatec AG, Stadthof 2, CH-3380 Wangen a. Aare, Switzerland; https: / / simatec.com / de / ) or SFF (SKF Sverige AB, from Utfallsgatan 2, Gothenburg, SE-415 50, Sweden; https: / / www.skf.com / ) may preferably be used as gas-generating cell controlled releasing devices. The automatic lubricators Simalube™ from simatec and SYSTEM 24™ from SKB are particularly suitable.These are developed for the lubrication of machines, but according to the invention they can be used for the present invention. The lubricators are available empty (without lubricant filling) in different sizes, which allows adaptation to different target applications according to the size of the areas to be treated.

[0109] Said hydrogen-powered lubrication devices have not yet been used in pest control preparedness. Therefore, a further aspect of the invention relates to the use of an automatic lubrication device with a gas-generating cell for releasing at least one insecticide or pesticide, wherein the lubricating device is filled with at least one insecticide or pesticide, preferably with an insecticide with larvicidal properties, instead of lubricating oil.

[0110] The insecticide can be released either continuously or, in a preferred embodiment, discontinuously at defined time intervals (periods). The periods are set so that it is shorter or equal to the reproduction cycle of the mosquito species to be controlled. While the invention is primarily suitable for controlling the tiger mosquito, other mosquito species - such as mosquitoes or Anopheles mosquitoes - can also be controlled. However, control of the tiger mosquito is preferred. Normally, the larvae of the tiger mosquito eclose from the eggs within five to ten days of egg laying, if the conditions are optimal, especially with water temperatures around 25 °C and sufficient food supply. These larvae then pass through several stages before growing into adult mosquitoes. The larvae of the tiger mosquito (Aedes albopictus) usually take between five and ten days to develop and eclose, depending on environmental conditions, especially water temperature. In optimal conditions, such as temperatures around 25 °C, this period can be shortened. Overall, the tiger mosquito goes through several stages of development: egg, larva, pupa and finally the adult mosquito. The entire development from egg to eclosing mosquito can vary between six and twenty days, depending on temperature and other factors. The insecticide with larvicidal properties should therefore ideally be released at (time) intervals of 5 to 30 days, preferably 5 to 20 days, more preferably 10 to 14 days or 7 - 10 days, especially preferably 7 or 8 days. The interval between the different releases can be equal of different. For example, the interval in spring and autumn, when temperatures are usually lower, can be longer than in summer. For example, the interval in spring and autumn can be about 20 days, while in summer it is about 10 days.

[0111] In another preferred embodiment, the insecticide with larvicidal properties is released, in the Northern hemisphere (such as Europe), in the months of April to October.

[0112] In the case of discontinuous dispensing, it is important that the gas pressure generated by the gas cell does not drop. For this purpose, a high gas tightness of the housing (see e.g. housing 100 in Fig 1 ) and a gas-tight fit of the movable piston (see e.g. piston 105 in Fig. 1 ) are important. Ideally, the container (reservoir) is made of a material that reduces the volatilization of hydrogen gas to a minimum. This can be, for example, glass, metal (e.g. aluminum) or a plastic with corresponding properties. Together with the movable piston (e.g. piston 105 in Fig. 1 ), the gas-generating cell (e.g. gas-generating cell 103 in Fig. 1 ), and optionally the enclosing socket or thread (see e.g. socket or thread 102 in Fig., 1 ), it forms an expandable chamber (gas volume) for receiving the gas (see e.g. chamber / gas volume 104 in Fig. 1 ). The container (reservoir) can be designed as a reusable container (reservoir) or as a recyclable disposable container (reservoir). While a good gas tightness can already be achieved with metallic containers, this can be improved by an inner coating, for example with polymers or two-component coatings. This is the case with the lubrication devices from Simatec, for which reason they are particularly preferred.

[0113] The device according to the invention offers a high level of operational and environmental safety, especially with the metallic embodiment. The active substance is encapsulated and, in case a check valve is present (see e.g. check valve 107 in Fig. 1 ), can only be released after activation of the gas cell (see e.g. gas-generating cell 103 in Fig. 1 ).

[0114] In a preferred embodiment, the device comprises a substantially cylindrical barrel (see e.g. the barrel-like cylindrical housing 100 in Fig., 1 ), in which the piston is arranged in a sealing and slidable manner along a length axis of the barrel (see e.g. piston 105 in Fig. 1 , piston 10-1 in Fig. 10, piston 11 -1 in Fig. 11 , piston 13-1 in Fig. 13). The piston divides at least a portion of an inner volume of the barrel into a preparation volume defining the reservoir for holding the insecticide with larvicidal properties (see e.g. reservoir / preparation volume 106 in Fig. 1 , reservoir / preparation volume 10-2 in Fig. 10, reservoir / preparation volume 11 -2 in Fig. 11 ,reservoir / preparation volume 12-2 in Fig. 12, or reservoir / preparation volume 13-2 in Fig. 13) as well as a gas-tight gas volume for receiving gas generatable by the gasgenerating cell (see e.g. gas volume 104 in Fig. 1 , gas volume 10-3 in Fig. 10, gas volume 11-3 in Fig. 11 , gas volume 12-3 in Fig. 12, or gas volume 13-3 in Fig. 13). The device is configured such that the piston is movable by pressure built up by the gas-generating cell in the gas volume so that the pressure-driven movement of the piston pushes the preparation of the at least one insecticide out of the outlet of the reservoir.

[0115] The piston as a movable component inside said barrel preferably creates suction to draw e.g. a fluid preparation of at least one insecticide in or push it out. A stopper made of rubber or another elastomer as a piston tip that creates a tight seal at the end of the piston for better leak prevention and smoother movement. At an outlet of the reservoir (see e.g. outlet 108 in Fig. 1 , outlet 10-6 in Fig. 10, or outlet 11 - 6 in Fig. 11 , the device comprises a connector, e.g. a luer lock-like connector or slip tip-like connector, that is capable to enable connection of additional attachments. In a preferred embodiment the device may be a barrel of a medical syringe.

[0116] In particularly preferred embodiments, as shown in Fig. 10, 11 and 13, the device is configured to release the insecticide discontinuously in defined time intervals (periods) while the gas release from the gas-generating cell is constant. In these embodiments, there is no need for an active control of the gas-generating rate, especially no need for an electronic control unit, such as a microcontroller. The constant gas generation rate of the gas-generating cell may be simply controlled by an electrical resistor, preferably a variable electrical resistor (potentiometer).

[0117] In the embodiments shown in Fig. 10, 11 , and 13, the discontinuous release of the insecticide is controlled by a mechanical control system. This is realized by a physical retarding structure that is configured to temporarily block or delay the pressure-driven movement of the piston in a plurality of retarding sections along the length axis of the barrel as long as the pressure built up by the gas-generating cell in the gas volume is below a pre-defined threshold range. In Fig. 10 and 11 , the retarding structure comprises a plurality of circumferential recesses formed in the inner surface of the barrel at equal intervals along the length axis of the barrel, one in each retarding section. The recesses provide a mainly form-fit based mechanicalresistance to the movement of the piston, e.g. in that a corresponding structure of the piston temporally interferes or engages with the recesses in form -fit manner. This mechanical resistance causes the piston to temporarily stop at a respective recess until the pressure created by the gas-generating cell increases again to reach or exceed a pre-defined threshold range, so that the piston is pushed over the recess (under deformation of the corresponding structure) and is moved to the next recess, thereby releasing a defined amount of insecticide that is determined by the volume between two adjacent recesses. The recesses and the amount of gas released by the gas-generating cell are configured so that the piston overcomes the mechanical resistance provided by the recesses after a predefined time interval or period as a consequence of the pressure increasing during the stop of the piston due to the continuous gas generation. Once the mechanical resistance is overcome by the increasing pressure, the piston is moved forward - also pressure-driven - to the subsequent recess, thereby releasing the next bolus, i.e. , defined amount, of the insecticide.

[0118] The recesses in the retarding sections at the inner surface of the barrel as shown in Fig. 11 and 12 may be formed as grooves, which can be formed in the inner surface of a barrel means of a lathe or similar machining device. Alternatively, the recesses in the retarding sections can already be made during the manufacturing of the barrel , e.g. by using during an injection molding process a correspondingly formed injection mold for the retarding structures.

[0119] Preferably, the retarding structure comprises at least 5 recesses or retarding sections, preferably at least 10 recesses or retarding sections. In Fig. 10 and 11 , the respective retarding structure comprises 6 recesses. The width and depth / height of the retarding sections determined the time interval between the different releases. For example, the recesses or the retarding sections can have a width of about 0.01 to 1 mm, preferably 0.2 to 0.2 mm, and a depth / height of between 0.01 and 1 mm, preferably 0.2 to 0.2 mm. The interval space / distance between two adjacent recesses or between two adjacent retarding sections is defined by the volume of the insecticide which should be released (per bolus) and may in a range between 2 mm and 30 mm, preferably 0.5 to 10 mm.

[0120] As described above, the piston comprises a corresponding structure designed in a way that it interferes with the recesses at the inner surface of the barrel to temporarily block or delay the pressure-driven movement of the piston until a predefined pressure threshold range is reached in the gas volume. Such a corresponding structure may comprise one or more flexible or elastically deformable fins, or one or more elastically deformable contour ridges, preferably extending around the outer circumference of the piston (see Fig. 10 - showing one deformable contour ridge [two or more deformable contour ridges are also possible]). Alternatively, the entire piston may be made out of an elastomer material such as rubber (Fig. 11 ). The person skilled in the art is aware that there are numerous ways to design the piston accordingly in terms of shape and material of the piston.

[0121] In a preferred embodiment, the corresponding structure is provided by a sealing member of the piston, e.g. as shown in Fig. 11 , where the piston comprises at least one elastically deformable fin as sealing member that is able to temporarily engage with the recesses forming the retarding structure. Alternatively, the corresponding structure may comprise an O-ring, e.g. made of flexible rubber material, that is arranged at the outer circumference and / or an end of the piston and may be used as cylindrical sealing member (see e.g. Fig. 12). Such O-rings are, for example, used in medical syringes. The material of the O-ring can expand to fit into the recesses in the inner surface of the barrel. It also increases the friction that has to be overcome to trigger the bolus release. Alternatively, the seal is provided in form of a plastic fin, preferably with a thin, flexible tip. The fin is spread by the pressure or counterpressure.

[0122] Fig. 13 shows a friction-based mechanical control system comprising a retarding structure 13-5 showing intermittent changes in the surface roughens of the inner surface of the barrel 13-4 along its length axis, causing intermittent changes in friction between the barrel 13-4 and the piston 13-1 along the length axis of the barrel. For example, the inner surface of the barrel in the one or more retarding sections may be roughened as compared to the inner surface at other sections along the length axis of the barrel. Alternatively, the inner surface of the barrel in the one or more retarding sections may be formed by a different material than other sections along the length axis of the barrel so as to provide increased friction between the barrel 13- 4 and the piston 13-1 .

[0123] The retarding structure and the amount of gas released from the gasgenerating cell are configured in a way that the time interval or period for the release of the larvicidal insecticide is in a range between 7 days and 30 days, preferably between 10 days and 14 days. The interval between the different releases can be equal of different. For example, the interval in spring and autumn when temperature is usually lower can be longer than in summer. For example, the interval in spring and autumn can be about 20 days, while in summer it is about 10 days.

[0124] For the purpose of controlled dispensing, the apparatus of the invention comprises in a preferred embodiment a control unit for the periodic release of the insecticide with larvae-killing properties. For the control unit, the person skilled in the art has various commonly known designs at his disposal.

[0125] The control unit is selected from the group consisting of (i) a timer, preferably an electronic timer that activates the gas-generating cell at specified time intervals, and (ii) a receiver for wirelessly transmitted signals - for example signals transmitted via Bluetooth - by which the guest winding cell is activated. Suitable circuits can be created, for example, using the microelectronic timer (timer; such as IC NE555). An example for a suitable circuit is provided in Fig. 14. There, a battery 14-1 powers a microcontroller 14-2, with its plus terminal being connected to the VCC terminal of the microcontroller (supply voltage) and the minus terminal being connected to the GND terminal of the microcontroller (mass). A program with a timer runs on the microcontroller, thereby causing a time clock to switch power to a pin terminal of the microcontroller. The pin terminal is connected to a MOSFET 14-3 to switch on the gas-generating cell. If there is power on the pin, the connection between the plus and minus is established and the gas cell 14-5 is switched on. A resistor 14- 4 is used to determine the gas generating rate. In a preferred embodiment, the resistor is a potentiometer (i.e. , a variable resistor).

[0126] The time intervals between the subsequent releases of the insecticide can be equal or different. For example, the time interval in spring and autumn, when temperatures are usually lower, can be longer than in summer. For example, the interval in spring and autumn can be about 20 days, while in summer it is about 10 days.

[0127] In an advantageous design of the present invention, the device can be extended with electronics and sensors for bidirectional data exchange, e.g. for the transmission of control and / or balancing data for gas generation. Furthermore, a combination with electronics, sensors, etc. is conceivable, for example, to enable communication with a mobile device (smartphone, etc.), to determ ine / transm it data or to allow a certain control or regulation. Corresponding devices and control software are available, for example, from Simatec (app "simatec world of maintenance"). They make it possible to record application locations, set the necessary parameters for the application and control and monitor all activities around the application. For example, the simalube™ IMPULSE connect, which is equipped with Bluetooth®, can be configured directly via the app.

[0128] In a preferred embodiment, premature leaching of the insecticide from the exposure sites due to prolonged rainfall is avoided in that the device comprises a moisture sensor that prevents the insecticide from being released during rainfall. This is especially preferred for a periodic release of the active ingredient. As soon as the rain stopped and the surface of the device has dried again, the dispensing continues. Preferably, the humidity sensor is mounted on the top side of the device.

[0129] Primary exposure sites, in particular for the tiger mosquito are cool, shady places with stagnant water, such as sludge collectors, drains, gullies or rain barrels. These are usually places with stagnant water, preferably without direct sunlight. Preference is given to sludge collectors (gullies or drains) for surface water on roads and pavements or on rain pipes, as well as rain barrels and other rainwater collection containers such as cisterns. In a preferred embodiment, the device according to the invention is attached to these places of exposure, preferably to the cover or to the ceiling. For this purpose, in a preferred embodiment, the device comprises an attachment means which allows for the attachment of the device to the underside of covers, preferably covers of sludge collectors, drains, gullies or rain barrel covers or ceilings of cisterns. The attachment means can be made by magnet, adhesive or by clamps. For metallic covers, attachment via magnets is preferred (see e.g. attachment means 111 in Fig. 3). In the case of non-metallic ceilings (plastic or concrete), a metal plate is first glued, to which the releasing device is then attached by the magnetic attachment means. Corresponding approaches are known from the attachment of smoke detectors. The attachment means is oriented in such a way that the outletopening for the insecticide preferentially points downwards towards the water surface (see e.g. Fig. 3). If a humidity sensor is used, the fastener is preferably oriented so that the humidity sensor points upwards and the outlet opening for the insecticide preferably downwards towards the water surface.

[0130] In a preferred embodiment the attachment means enables easy positioning while preventing easy (unauthorized) removal. Such attachment means can be easily and cheaply created using flexible spring steel as e.g. illustrated in Fig. 15, which schematically shows a U-shaped attachment means 15-1 made from spring steel: This attachment means can be introduced into a drain opening of a drain cover such that the releasing device - coupled to the lower end of the attachment means 15-1 via a cord 15-2 - is positioned below the drain cover. Angled wing ends of the U-arms securely hold the attachment means 15-1 in the drain opining, while elastic folding wings prevent unauthorized removal of the attachment means 15-1 from the drain cover. The attachment means 15-1 and the releasing device can only be removed using a removing tool 15-4 comprising a magnet for magnetically retracting and thus disengaging the folding wings.

[0131] In a preferred embodiment, the device according to the invention is at least protected against splash water and rain water, preferably it is waterproof. This is the case with the lubrication devices from Simatec. These are even suitable for underwater use.

[0132] In order to ensure a high level of reliability and freedom from maintenance, the device of the invention in a preferred embodiment does not include any functionally relevant, electromechanical elements such as motors, especially not those that could be subject to wear.

[0133] In case of mass distribution and if costs are a major constraint, one-way syringes with corresponding rubber pistons are also suitable, as illustrated in Fig. 16. There, a barrel 800 of a one-way syringe is used as barrel for a device according to the present embodiment. Inside the barrel 800, a rubber piston 805 is arranged in a sealing and slidable manner along a length axis of the barrel. The piston 805 divides at least a portion of an inner volume of the barrel 800 into a preparation volume 806 defining the reservoir for holding an insecticide preparation, and a gas volume 804 for receiving gas generatable by a gas-generating cell 803 (controlled by a controlunit 801 ) in order to build up pressure for moving the piston 805 towards an outlet 807. The gas-generating cells 803 and the control unit 801 can be easily fastened to the barrel 800 of the syringe by clamps 802 or other fastening devices.

[0134] In a preferred embodiment, the apparatus of the invention and the method of the invention comprises an insecticide with larvicidal properties, which contains at least one active substance, selected from the group consisting of(i) toxins, spores or mixtures thereof of at least one Bacillus strain, preferably of at least one Bacillus thuringiensis israelensis (Bti) strain, such as Bacillus thuringiensis israelensis (Bti) serotype H14 (preferably strain AM65-52)(ii) pyrethrum or pyrethrum-like substances (called pyrethroids)(iii) essential oils(iii) chemical insecticides.

[0135] Preferred essential oils are, for example, citronella, geraniol, lemongrass, peppermint, cedar oil, eugenol.

[0136] Preferred pyrethroids are, for example, metofluthrin, transfluthrin, allethrin, bifenthrin, cyhalothrin, lambda-cyhalothrin, cypermethrin, cyfluthrin, deltamethrin, etofenprox, fenvalerate, permethrin, phenothrin, prallethrin, resmethrin, tetramethrin, tralomethrin.

[0137] Preferred chemical insecticides are, for example, imidacloprid, heptachlor, methoxychlor, mirex, pentachlorphenol, organophosphate compounds like acephate, Azinphos-methyl, Bensulid, Chlorethoxyfos, Chlorpyrifos, Chlorpyriphos-methyl, Diazinon, Dichlorvos (DDVP), Dicrotophos, Dimethoat, Disulfoton, Ethoprop, Fenamiphos, Fenitrothion, Fenthion, Fosthiazat, Malathion, Methamidophos, Methidathion, Mevinphos, Monocrotophos, Naled, Omethoat, Oxydemeton-methyl, Parathion, Parathionmethyl, Phorat, Phosalone, Phosmet, Phostebupirim, Phoxim, Pirimiphosmethyl, Profenofos, Terbufos, Tetrachlorvinphos, Tributes, Trichlorfon; Carbamate wie wie Aldicarb, Bendiocarb, Carbofuran, Carbaryl, Dioxacarb, Fenobucarb, Fenoxycarb, Isoprocarb, Methomyl, 2-(1 -Methylpropyl)phenylmethylcarbamat; Neonicotinoide like Acetamiprid, Clothianidin, Imidacloprid, Nitenpyram, Nithiazin, Thiacloprid, Thiamethoxam .

[0138] Particularly advantageous are environmentally friendly biological agents Bacillus thuringiensis israelensis (Bti) strains, for example Bacillus thuringiensis israelensis (Bti) serotype H14 (preferably strain AM65-52). Bti strains produce toxins that are ingested by the mosquito larvae with their food and cause a specific, fatal intestinal disease. Bti is very specific against mosquito larvae. Phytotoxic effects are not known. The skilled person is familiar with how to determine the optimum amount of active substance in each case depending on the surface area and the water volume of the exposure area (Lai L et al. Bacillus thuringiensis Cyt Proteins as Enablers of Activity of Cry and Tpp Toxins against Aedes albopictus). Toxins (Basel). 2023 Mar 10; 15(3):211. doi: 10.3390 / toxinsl 5030211 ). According to Lai et al., the LC50 (median lethal concentration) is 178 ng / mL for Cry4Aa, 46 ng / mL for Cry4Ba, 228 ng / mL for Cry11Aa, and 171 ng / mL for CytlAa. These values indicate the concentration at which 50% of the larvae died.

[0139] For applications, it is best to follow the manufacturer's recommended dosage for commercial Bti products for tiger mosquito control. The form of application according to the invention does not require any special adjustments here. A target concentration of 10,000 ITU / I is usually sufficient.

[0140] The Bti preparation may comprise intact Bti cells which are intact and substantially in the proliferative form when treated, and / or spores. Also the application of Bti derived crystal proteins can be considered.

[0141] In a preferred embodiment, the insecticide to be released is in the form of a powder, a paste, a pellet, a gel, a liquid or a combination thereof. Preferred are liquid or gel-like formulations. Suitable preparations are, for example, commercial Bti formulations such as VectoBac™ 12 AS (Valent BioSciences Corp.) or Aquabac™ XT (Andermatt Biocontrol Suisse AG, Stahlermatten 6,6146 Grossdietwil; Switzerland). Depending on the size of the application device and the area of exposure, the concentration of the active substance must be adjusted so that at least 30 doses (one dose per week for the period from April to October), preferably 35 doses, can be released. When using the 125 ml Simalube™ unit, this would be doses of about 3.5 ml. The commercially available Bti preparations are usually diluted forthis purpose. A pilot study for the respective forms of exposure (gully, dole, rain barrel) is useful in order to determine the most effective and economical concentrations for different scenarios.

[0142] The insecticidal preparation may comprise one or more additives which enhance its stability, uniformity, and homogeneity such as preservatives, emulgents, dispersant (dispersing agents) etc. The formulations may include spreader-sticker adjuvants, stabilizing agents, other pesticidal additives, or surfactants. Liquid formulations may be aqueous-based or non-aqueous and employed as foams, gels, suspensions, emulsifiable concentrates, or the like. The ingredients may include rheological agents, surfactants, emulsifiers, dispersants, or polymers. Specific formulations for Bt preparation are known to the person skilled in the art and described for example in EP0448070B1 (Insecticidal composition based on Bacillus thuringiensis).

[0143] In a further preferred embodiment, the insecticidal preparation comprises a surfactant, preferably an anionic surfactant, capable of lowering the surface tension of a liquid, e.g. water, in which the insecticidal preparation is released. As mosquito larvae have to adhere to the surface of the water reservoir to breathe, adding a surfactant reduces the surface tension and causes the larvae to sink to the bottom of the reservoir where they cannot receive oxygen and die.

[0144] In a preferred embodiment, the device can be refilled with the insecticidal active substance at least once. Refilling is preferably done by a specialist.

[0145] In another preferred embodiment the methods of the invention are applied to multiple exposure sites in a larger area, such as a city. Here, the reliability and cost efficiency of the invention is especially useful. In such a situation, there are often hundreds or thousands if exposition sites which need to be managed. Here, the easy installation, removal, and / or exchange of the devices of the inventions (as shown for example in Fig. 15) is preferred. Thus, another embodiment of the invention relates to a system comprising at least 10, more preferred at least 100, most preferred at least 1000 exposition sites, wherein at least 50%, more preferred at least 75%, most preferred at least 90% of the exposition sites are prepared with a device of the invention.

[0146] As mentioned further above, a separate aspect of the invention relates to a barrel for use in a device according to the present invention and as described herein. Exemplary embodiments of such a barrel are shown in Fig. 17. The barrel comprises at an inner surface a retarding structure 17-1 , 17-2, 17-3 in a plurality of retarding sections along a length axis of the barrel, wherein the retarding structure is configured to temporarily block or delay a pressure-driven movement of a piston at said retarding sections along the length axis of the barrel as long as the pressure is below a pre-defined threshold range. Preferably, the barrel comprises at least 2, in particular at least 5, more particularly at least 10 retarding sections, wherein the retarding sections are arranged intermittently, preferably at equal intervals, along the length axis of the barrel. Preferably the retarding sections are configured as described above.

[0147] Fig. 17 shows three different embodiments A, B and C of the barrel. In embodiment A, the retarding structure of the barrel comprises intermittent enlargements of its inner cross-section which are formed by circumferential recesses 17-1 , e.g. grooves, in the inner surface. Vice versa, in embodiment B, the retarding structure of the barrel comprises intermittent enlargements intermittent diminutions of its inner cross-section formed by circumferential ridges at the inner surface of the barrel. Finally, in embodiment C, the retarding structure of the barrel comprises an intermittent combination of recesses (grooves) and protrusions (ridges).

[0148] In a preferred embodiment the barrel is part of a device comprising- a barrel as described above, forming a reservoir- a piston positioned in the barrel- a gas-generating cell configured to build up a pressure by means of gas generation, at a first end of the barrel,- an outlet at a second end of the barrel, wherein the device is configured such that pressure built up by the gas-generating cell causes movement of the piston towards the outlet of the reservoir.

[0149] Although this disclosure describes a limited number of embodiments, variations, modifications, and other applications of such embodiments are possible. The disclosure is to be understood as not being limited by the specific embodiments described herein, but only by the scope of the attached claims.Example 1 : Bioassay - Determination of viable larvae

[0150] A representative water sample is taken from different areas of the exposure source using small 10 ml scoop cups with style. The number of larvae in the samples is determined, the average for a single source of exposure is calculated and extrapolated to the total volume. Larvae that have already died sink to the ground and are ignored in the count. The count can be done either with the naked eye or an app.

[0151] Various tests for the counting and effectiveness determination of Bti against the tiger mosquito are known to the expert (Pluskota B et al. (2018) Studies on the effectiveness of monitoring and control measures for the development of a catalogue of measures for the integrated control of the Asian tiger mosquito in Baden- Wurttemberg. KLIMOPASS reports series. Project no.: 4500489832 / 23. Under: https: / / pudi.lubw.de / detailseite / -Zpublication / 35867- Untersuchungen_zur_Effektivit%C3%A4t_von_Monitoring- _und_Bek%C3%A4mpfungsma%C3%9Fnahmen_f%C3%BCr_die_Entwicklung_ein es_M.pdf)Example 2: Device Adjustment 1

[0152] Empty Simalube™ devices with a filling volume of 125 ml are modified to release 3.5ml within 1 to 10 hours in a defined interval of 5 to 25 days. The device can generate a pressure of up to 10 bar and is available with dispenser sizes of 60, 125 and 250 ml. For interval switching, the commercially available devices are equipped with a micro timer.Example 3: Device Adjustment 2

[0153] A 20 ml or 50 ml one-way syringe is prepared for release of a larvicidal insecticide as shown in Fig. 16. For periodic release a plurality of intermittent recesses is created by using a conventional lathe. The release of the gas-generating cell is adjusted to move the piston from one recess to a next every 7, 14, or 21 days.Example 4: Efficacy test

[0154] In particular, commercially available liquid Bti formulations were tested:(i) VectoBac™ outlet / supply line (hose) to the lower water reservoir 12AS: Active substance Bacillus thuringiensis, subsp. israelensis, strain AM65-52 (11.61 %). Effectiveness: 1200 International Toxic Units (ITU) per mg, equivalent to 1 .279 billion ITU per liter.(ii) Aquabac™ XT: Contains spores and toxins of Bacillus thuringiensis israelensis (B. t. i.). Content Bacillus thuringiensis var. Israelensis serotype H14, strain AM65-52, 8 percent. Potency: 1200 ITU / mg.Example 4: Efficacy test

[0155] The optimal concentration of the active substance can be calculated according to the surface area for shallow sources of exposure, and according to the volume for lower sources. For active substance preparations with an active substance concentration of 1200 ITU / mg, it is approx. 0.25 - 1 .00 ml / m2 (for surface applications in shallow waters) or 2.5 - 10 mg / l (3000 - 12000 ITU / I for applications in reservoirs such as rain barrels).

[0156] The effect of biological Bti preparations depends on various factors, such as the dose used, the water quality, the temperature and the mosquito species. Concentrations of 11 ,000 ITU / litre are sufficient to prevent the growth of third larvae for 15 days and for first larvae for 30 days in rain barrels without water circulation. Organically contaminated rain barrels required a dose of Bti. about twice as high for the same long-term effect. Based on the trials, a Bti. dose of 8,000 - 9,000 ITU / liter is recommended for the initial treatment of rain clay and other breeding sites of the Asian tiger mosquito. If the rain barrels are not completely emptied afterwards or washed through by heavy rainfall events, follow-up treatment in a 3-week rhythm with a reduced dose of 5,000 - 6,000 ITU / liter is sufficient. The concentration is adjusted in such a way that approx. 1 - 4 ml of active substance solution per exposure source is delivered by the apparatus according to the invention. For this purpose, the commercially available means are usually to be diluted 1 :3 to 1 :20.

[0157] For a gully (drain), a water reservoir of a maximum of 10 liters is assumed. Applications of 120,000 - 240,000 ITU (100 - 200 mg with an active substance centricity of 1200 ITU / mg) are usually effective for this purpose. For this purpose, the commercially available means are usually to be diluted. The concentration is adjustedin such a way that approx. 1 - 4 ml of active substance solution per exposure source is delivered by the apparatus according to the invention.

[0158] In some embodiments the effective dose is calculated based on the surface of the reservoir than its total volume. In these cases, usually a dose of 250 g to 500 g BTI per 10'000 m2(i.e., 0,025 g to 0,05 g per m2). With a usual effectiveness of 1200 International Toxic Units (ITU) per mg, this equals 30,000 to 60,000 ITU per square meter (m2) of treated surface.

[0159] Table 1 : Test results gully+++ = High concentration of viable larvae; ++ = Medium concentration of viable larvae; + = Low concentration of viable larvae; 0 = No viable larvae.

Claims

CLAIMS1 . A device for releasing an insecticide suitable for controlling mosquito larvae, the device comprising: a reservoir containing a preparation of at least one insecticide having larvicidal properties, wherein the reservoir comprises an outlet for releasing the preparation of the at least one insecticide, a gas-generating cell configured to build up a pressure by means of gas generation, wherein the device is configured such that pressure built up by the gasgenerating cell causes movement of the preparation of the at least one insecticide out of the outlet of the reservoir.

2. The device according to claim 1 , wherein the device comprises a barrel and a piston arranged in the barrel in a sealing and slidable manner along a length axis of the barrel, wherein the device is configured such that the piston is movable by pressure built up by the gas-generating cell so that the pressure-driven movement of the piston pushes the preparation of the at least one insecticide out of the outlet of the reservoir.

3. The device according to claim 2, wherein the piston divides at least a portion of an inner volume of the barrel into a preparation volume defining the reservoir and a gas volume, in particular gas-tight gas volume, for receiving gas generatable by the gasgenerating cell to build up pressure for moving the piston.

4. The device according any one of claims 1 to 3, wherein the gas-generating cell is a hydrogen generating cell, preferably an essentially mercury-free hydrogen generating cell.

5. The device according to any of claim 1 to 4, wherein the device is configured to release the insecticide continuously or discontinuously at defined intervals, in particular intermittently, more particularly periodically.

6. The device according any one of claims 1 to 5, further comprising a control system, in particular a mechanical control system or an electrical control system, configured to allow a defined amount of the insecticide to be released at defined intervals.

7. The device according to claim 5 or 6, wherein the device, in particular the control system, is configured to control intermittent release, in particular periodic release, of the insecticide every 5 to 30 days, in particular every 5 to 20 days, preferably every 7 to 14 days, more preferably every 10 to 14 days or every 7 to 10 days, for example every 7 or 8 days.

8. The device according to any one of claims 5 to 7, wherein the device, in particular the control system, comprises a control unit for intermittent release, in particular periodic release, of the insecticide, which is one of:(i) a timer configured to activate the gas-generating cell at predetermined time intervals, and(ii) a receiver for wirelessly transmitted signals by which the gas-generating cell is activated, in particular a receiver configured to receive wirelessly transmitted signals for activating the gas-generating cell.

9. The device according to claim 3 and optionally any one of claims 4 to 8 , wherein the barrel comprises a retarding structure configured to temporarily block or delay the pressure-driven movement of the piston in one or more retarding sections along the length axis of the barrel as long as the pressure built up by the gas-generating cell in the gas volume is below a pre-defined threshold range.

10. The device according to claim 9, wherein the retarding structure provides a profile of varying mechanical resistance to the movement of the piston along the length axis, wherein the mechanical resistance in the one or more retarding sections is chosen to temporarily block or delay the pressure-driven movement of the piston aslong as the pressure built up by the gas-generating cell in the gas volume is below a pre-defined threshold range.

11. The device according to any one of claim 9 or 10, wherein in the one or more retarding sections the retarding structure comprises at least one enlargement and / or at least one diminution of an inner cross-section of the barrel.

12. The device according to any one of claims 9 to 11 , wherein in the one or more retarding sections the retarding structure comprises at least one protrusion, in particular at least one circumferential protrusion, for example at least one ridge, in particular at least one circumferential ridge, arranged at an inner surface of the barrel, the at least one protrusion preferably creating a diminution of an inner crosssection of the barrel along its length axis.

13. The device according to any one of claims 9 to 12, wherein in the one or more retarding sections the retarding structure comprises at least one recess, in particular at least one circumferential recess, for example at least one groove, in particular at least one circumferential groove, arranged at an inner surface of the barrel, the at least one recess preferably creating an enlargement of an inner cross-section of the barrel along its length axis.

14. The device according to any one of claim 9 to 13, wherein in the one or more retarding sections a material property of the inner surface of the barrel is chosen to provide increased friction between the barrel and the piston along the length axis of the barrel as compared to other sections along the length axis of the barrel.

15. The device according to any one of claims 9 to 14, wherein the retarding structure comprises at least 2, in particular at least 5, more particularly at least 10 retarding sections, wherein the retarding sections arranged intermittently, preferably at equal intervals, along the length axis of the barrel.

16. The device according to any one of claims 2 to 15, wherein the piston comprises a sealing member, in particular an elastic sealing member, providing a seal between the piston and the barrel.

17. The device according to claim 16 and any of claims 9 to 15, wherein the sealing member is configured to interact with the retarding structure in the one or more retarding sections to temporarily block or delay the pressure-driven movement of the piston.

18. The device according any one of the preceding claims, wherein the gas-generating cell is configured to generate gas with an alternating or a constant gas generation rate, wherein the alternating or the constant gas generation rate preferably is adjustable.

19. The device according any one of the preceding claims, further comprising an outlet valve, in particular an outlet check valve, at the outlet of the reservoir.

20. The device according any one of the preceding claims, further comprising a connector at the outlet of the reservoir, in particular a luer-lock connector or slip-tip connector.21 . The device according any one of the preceding claims, wherein the gas-generating cell is a hydrogen generating cell, preferably an essentially mercury-free hydrogen generating cell.

22. The device according any one of the preceding claims, further comprising a moisture sensor configured to prevent release of the insecticide during rainfall.

23. The device according any one of the preceding claims, further comprising attachment means configured to attach the device at the underside of an object, in particular of a cover.

24. The device according any one of the preceding claims, wherein the device is splash water protected and / or rain water protected, preferably waterproof.

25. The device according any one of the preceding claims, wherein the preparation of the at least one insecticide to be released, in particular the insecticide, is in the form of a powder, paste, pellet, gel, liquid or combination thereof.

26. The device according any one of the preceding claims, wherein the at least one insecticide having larvicidal properties contains at least one active substance, selected from the group consisting of:- toxins, spores or mixtures thereof of at least one Bacillus strain, preferably at least one Bacillus thuringiensis israelensis (Bti) strain, more preferable Bacillus thuringiensis israelensis (Bti) serotype H14, most preferably strain AM65-52,- pyrethrum or pyrethrum-like substances;- essential oils; and- chemical insecticides.

27. The device according any one of the preceding claims, wherein the preparation of the at least one insecticide further contains one or more additives configured to enhance stability, uniformity, and homogeneity of the preparation, and / or a surfactant.

28. A method for controlling mosquito larvae, in particular by releasing a preparation of at least one insecticide having larvicidal properties at one or more exposure sites, using a device according to any one of claim 1 to 27, wherein preferably an effective, especially defined, amount of the at least one insecticide having larvicidal properties is released every 5 to 30 days, more particularly every 5 to 20 days, especially every 7 to 14 days, more preferably every 10 to 14 days or every 7 to 10 days, for example every 7 or 8 days.

29. The method of claim 28, wherein the device is attached to the underside of a cover, in particular a cover of a drain or a cover of a sludge collector, a cover of cistern or a cover of a rain barrel.

30. The method of claim 28 or 29, wherein the method is applied to an area with at least 10, in particular at least 100, preferably at least 1000 exposure sites.31 . A system comprising at least 10, more preferred at least 100, most preferred at least 1000 exposure sites, wherein preferably at least 50%, more preferred at least 75%, most preferred at least 90% of the exposure sites are prepared with a device according to any one of claim 1 to 27.

32. A barrel for use in a device according to any one of claims 1 to 27, comprising at an inner surface a retarding structure in a plurality of retarding sections along a length axis of the barrel, wherein the retarding structure is configured to temporarily block or delay a pressure-driven movement of a piston at said retarding sections along the length axis of the barrel as long as the pressure is below a pre-defined threshold range.

33. The barrel according to claim 32, wherein the retarding structure provides a profile of varying mechanical resistance to the movement of the piston along the length axis, wherein the mechanical resistance in the one or more retarding sections is chosen to temporarily block or delay the pressure-driven movement of the piston as long as the pressure built up by the gas-generating cell in the gas volume is below a pre-defined threshold range.

34. The barrel of according to any one of claim 32 or 33, wherein in the one or more retarding sections the retarding structure comprises at least one enlargement and / or at least one diminution of an inner cross-section of the barrel.

35. The barrel according to any one of claims 32 to 34, wherein in the one or more retarding sections the retarding structure comprises at least one protrusion, in particular at least one circumferential protrusion, for example at least one ridge, in particular at least one circumferential ridge, arranged at an inner surface of the barrel, the at least one protrusion preferably creating a diminution of an inner crosssection of the barrel along its length axis.

36. The barrel according to any one of claims 32 to 35, wherein in the one or more retarding sections the retarding structure comprises at least one recess, in particular at least one circumferential recess, for example at least one groove, in particular at least one circumferential groove, arranged at an inner surface of the barrel, the atleast one recess preferably creating an enlargement of an inner cross-section of the barrel along its length axis.

37. The barrel according to any one of claim 32 to 36, wherein in the one or more retarding sections a material property of the inner surface of the barrel is chosen to provide increased friction between the barrel and the piston along the length axis of the barrel as compared to other sections along the length axis of the barrel.

38. The barrel according to any one of claims 32 to 37, wherein the barrel comprises at least 2, in particular at least 5, more particularly at least 10 retarding sections, wherein the retarding sections arranged intermittently, preferably at equal intervals, along the length axis of the barrel.

39. A device comprising- a barrel according to any one of claims 32 to 38,- a piston arranged in the barrel in a sealing and sliding manner, wherein the piston divides at least a portion of an inner volume of the barrel into a preparation volume and a gas volume, in particular gas-tight gas volume,- a gas-generating cell at a first end of the barrel which is configured to build up a pressure in the gas volume by means of gas generation,- an outlet from the preparation volume at a second end of the barrel, wherein the device is configured such that pressure built up by the gas-generating cell causes movement of the piston towards the outlet.

0. The device according to claim 39, wherein the piston comprises a sealing member, in particular an elastic sealing member, providing a seal between the piston and the barrel. 1 . The device according to any one claim 39 or 40, wherein the device further comprises a treatment composition contained in the reservoir volume between the piston and the outlet, wherein the device is configured such that pressure built up by the gasgenerating cell causes movement of the treatment preparation out of the outlet of the reservoir.

2. The device according to any one of claim 39 to 41 , wherein the treatment preparation is a composition suitable for at least one application selected from the group consisting of:- pharmaceuticals and drug delivery use,- agriculture use, preferably fertilizer or crop protection use,- pest control use,- cosmetics use,- industrial and environmental applications, and- veterinary medicine and animal care.

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