Device for controlling varroa mites

Abstract

The invention relates to a device for preventing the development of varroa mites or for eliminating varroa mites present in a beehive, the device comprising: a) a plasma-generating unit, which has a plasma-discharge area of 1.0 cm2 to 6.0 cm2, preferably 2.5 cm2 to 3.5 cm2, wherein the plasma-generating unit has a plasma outlet so that plasma can be introduced into the beehive; b) a control device, which is connected to the plasma-generating unit, wherein the control device is designed such that the plasma power density of the discharge area can be adjusted at the plasma-generating unit, wherein the plasma power density of the discharge area is adjusted to 0.2 W / cm2 to 1.0 W / cm2, preferably 0.3 W / cm2 to 0.6 W / cm2.

Description

[0001] Device for controlling varroa mites

[0002] The present invention relates to a device for preventing the formation of Varroa mites or for eliminating existing Varroa mites in a beehive. Furthermore, the invention relates to a method for preventing the formation of Varroa mites or for eliminating existing Varroa mites in a beehive.

[0003] BACKGROUND OF THE INVENTION

[0004] For several years, the Varroa mite (Varroa destructor) has been causing significant damage to beehives and is considered the main cause of colony collapse. The Varroa mite is a parasite that infects both adult bees and their brood and feeds on the bees' hemolymph, reducing the bees' strength and life expectancy and potentially transmitting diseases. Because the Varroa mite reproduces very rapidly within a hive, early control is essential.

[0005] Various methods are currently used to combat Varroa mites in beehives. For chemical control of the Varroa mite, beekeepers have so far used formic acid, for example, which is applied to a sponge and placed in the hive to evaporate. However, it has been determined that this treatment is not yet effective enough to reduce mite infestations throughout the region. Lactic and oxalic acid are also used as agents against Varroa mites. Another form of chemical treatment involves the use of acaricides to reduce mite populations in beehives. All of these agents form residues in honey, and resistance among the mites is increasingly being observed, so these methods are declining. In biological treatment, beekeepers use predatory mites, which are natural enemies of Varroa mites. However, this method is laborious and slow.Mechanical control methods for the Varroa mite include the removal of infested brood or the use of drone traps to interrupt Varroa mite reproduction. However, this method is usually applied at a time when the hive is already heavily infested. Thermal treatment relies on heating hives to create a climate that is lethal to the mites but still tolerable for the bees. However, this approach places a high level of stress on the bees and their brood. Combinations of these methods, and of course, breeding measures through the selection of bees with increased resistance, are also used. Nevertheless, no method has yet been found that sufficiently rids hives of the Varroa mite.

[0006] KR 10-2142484 B 1 describes a hive cover that is attached to an open side of the hive and features a plasma generation unit. Plasma is blown into the hive using a fan. The device described in KR 10-2142484 B1 is technically complex and has the disadvantage of producing a large amount of ozone, which is blown into the hive along with the plasma, causing significant stress to the bees and the brood. The fan also induces the bees to seal the fan opening with propolis.

[0007] DESCRIPTION OF THE INVENTION

[0008] All previous approaches aim to rid the already infested hive of Varroa mites. The solution described in KR 10-2142484 Bl is also designed to be applied to a hive already infested with Varroa mites and treat the infested hive with plasma.

[0009] The object of the present invention is therefore to provide a device which, on the one hand, fundamentally prevents the entry of the Varroa mite into the beehive and does not intervene only after infestation, and, on the other hand, combats the Varroa mite in an infested beehive.

[0010] This object is achieved by a device for preventing the formation of Varroa mites or for eliminating existing Varroa mites in a beehive, comprising: a) a plasma generation unit having a plasma discharge area of ​​1.0 cm 2 up to 6.0 cm 2 , preferably 2.5 cm 2 up to 3.5 cm 2wherein the plasma generation unit has a plasma outlet so that the plasma can be introduced into the hive, b) a control device which is connected to the plasma generation unit, wherein the control device is designed such that the plasma power density of the discharge area on the plasma generation unit is adjustable, wherein the plasma power density of the discharge area is set to 0.2 W / cm 2 up to 1.0 W / cm 2 , preferably 0.3 W / cm 2 up to 0.6 W / cm 2 This task is also solved by a

[0011] A method for preventing the formation of Varroa mites or for eliminating existing Varroa mites in a beehive, comprising the steps of: a) introducing a plasma outlet for plasma of a plasma generation unit into a beehive; b) activating the plasma generation unit to generate a plasma with a plasma power density of the discharge area of ​​0.2 W / cm2 up to 1.0 W / cm 2 , preferably 0.3 W / cm 2 up to 0.6 W / cm 2 .

[0012] The discharge area of ​​a plasma source is understood to be, in particular, a plasma electrode area. This area can be detected by a typical plasma glow under atmospheric conditions—particularly in the form of surface microdischarges.

[0013] The plasma outlet of a plasma source is the unit through which the plasma is introduced into the hive. This can occur through convection, diffusion, or ventilation.

[0014] Different operating modes have proven advantageous for both the device and the method, in which preferably a pulsed plasma generation occurs on the one hand and a continuous plasma generation on the other.

[0015] Therefore, in one embodiment, the device provides that the control device is designed such that it is possible to select between a first operating mode and a second operating mode, wherein with the plasma generation unit in the first operating mode a plasma power density of the discharge area of ​​0.2 W / cm 2 up to 0.45 W / cm 2 , preferably 0.3 W / cm 2 up to 0.45 W / cm 2 and in the second operating mode a plasma power density of the discharge area of ​​0.45 W / cm 2 up to 0.7 W / cm 2 , preferably 0.45 W / cm 2 up to 0.6 W / cm 2 can be delivered. Preferably, the plasma delivery is pulsed in the first operating mode and continuous in the second operating mode.

[0016] In one embodiment, the method provides that the plasma generation unit in the first operating mode has a power of 0.2 W / cm 2 up to 0.45 W / cm 2 , preferably 0.3 W / cm 2 up to 0.45 W / cm2 and in the second operating mode a plasma power density of the discharge area of ​​0.45 W / cm 2 up to 0.7 W / cm 2 , preferably 0.45 W / cm 2 up to 0.6 W / cm 2 Preferably, the first operating mode comprises continuous plasma delivery and the second operating mode comprises pulsed plasma delivery.

[0017] The choice between the operating modes depends on the season, temperature, and bee activity. The second operating mode is advantageous in the fall, especially after the honey harvest, and the first operating mode is advantageous in winter, spring, and summer. It is also possible to choose an intermediate range between these operating modes.

[0018] Surprisingly, it was found that with a discharge area of ​​1.0 cm 2 up to 6.0 cm 2 , preferably at 2.5 cm 2 up to 3.5 cm 2When operating in both modes, RNS (reactive nitrogen species) were preferentially generated by the plasma generation unit at low ozone concentrations. RNS, especially nitrogen oxides such as N2O5 and NO, penetrate deep into the honeycomb. This results in a reduction in mite infestation throughout the entire region of a hive. It was further determined that when using a larger discharge area, at a plasma power density of the discharge area of ​​0.3 W / cm 2 up to 0.6 W / cm 2 , an increased concentration of ozone and RNA occurs and therefore damage to bees and hive material cannot be ruled out.

[0019] The present invention represents an innovative solution that enables effective control of Varroa mites in beehives by using a safe and controlled plasma that kills the mites without harming the bees or the environment. The device and method are adaptable and can be modified according to the specific needs and conditions of different beehives.

[0020] By using the plasma generation unit and by inserting the insertion element into the hive, a plasma can be generated preventively in the hive, so that, for example, a Varroa mite introduced by a bee is immediately killed. It has been found that a plasma power density of the discharge area of ​​0.2 W / cm 2 up to 0.45 W / cm 2 , preferably 0.3 W / cm 2 up to 0.45 W / cm 2(Operating mode 1) causes no harm to the bees or brood during continuous treatment, while killing the Varroa mites. Furthermore, it has been shown that a plasma density of 0.45 W / cm 2 up to 0.7 W / cm 2 , preferably 0.45 W / cm 2 up to 0.6 W / cm 2 (Operating mode 2) is suitable for a burst treatment over several days, whereas the Varroa mites are killed within a very short time. During a burst treatment (operating mode 2), the bees form clusters, but no damage to the bees has been observed over 72 hours. Therefore, an operating mode in mode 2 should be set for a maximum of 72 hours.

[0021] In one embodiment, the plasma outlet can be arranged on an inlet element. The inlet element can be inserted into the hive, where it distributes the plasma directly within the hive. In this embodiment, the plasma generation unit can remain outside the hive. The inlet element can then comprise, for example, a perforated tube to distribute the plasma evenly throughout the hive.

[0022] The plasma outlet can also be attached directly to the plasma generation unit. In this case, the entire device can be introduced into the hive. An internal power supply (e.g., a battery) can be provided for this purpose. Plasma generation units require very little space and can be mounted directly in honeycombs or on the floor of hives. In one design variant, positioning them in a drawer beneath the hive has proven advantageous. Positioned this way, the plasma rises and spreads throughout the hive.

[0023] The invention therefore also relates to a beehive with a drawer arranged on the underside, preferably a drawer, in which a device of the aforementioned type is arranged.

[0024] The device can further be characterized by a sensor for detecting the presence of Varroa mites in the beehive, wherein the sensor is connected to the control device and wherein the control device activates the plasma generation unit when Varroa mites are present. In this way, for example, when there is a low presence of Varroa mites, the plasma generation unit can be operated in a synchronized manner over certain periods of time in operating mode 1, but when a high presence is detected, operating mode 2 can be activated for 0.2 hours to 72 hours, preferably 0.3 hours to 2 hours. If no Varroa mites are detected, the plasma generation unit can be deactivated. The sensor for detecting the presence of Varroa mites can comprise a camera with an image analysis function and / or infrared sensors. The use of optical sensors and image analysis technology enables automatic detection of Varroa mites in a beehive.Infrared sensors can detect vibration detection patterns of the bees, and changes in the behavior or condition of the bees can be used to determine whether the changed vibration patterns indicate a mite infestation.

[0025] If Varroa mite presence is detected by the sensor, the control device can activate and regulate the plasma generation unit until the sensor can no longer detect Varroa mite presence.

[0026] The plasma generation unit can be activated for a predetermined duration to effectively kill the Varroa mites without harming the bees.

[0027] After a certain period of time, the plasma generation unit can be deactivated.

[0028] Regarding the type of plasma, it has been shown that Varroa mites can generally be effectively controlled with plasma, but the bees, and especially the brood, also react sensitively to the introduction of plasma. It can be observed that the bees react with stress at certain plasma power densities of the discharge area. The plasma details described in KR 10-2142484 Bl showed negative, stressed behavior in the bees. This was not observed with the claimed plasma power density of the discharge area in preferred operating mode 1.

[0029] The plasma generation unit is designed to use a dielectric barrier discharge (DBD) to generate plasma at room temperature and atmospheric pressure. A plasma generation unit that is particularly suitable according to the invention is described below. One such unit is described, for example, in DE 10 2021 203 211 B3.

[0030] The plasma generation unit is suitable for atmospheric dielectric barrier discharge and comprises a glass tube and an inner electrode made of bundled stainless steel fibers, wherein the bundled stainless steel fibers are arranged spirally inside the glass tube, with an outer electrode designed as a sieve cylinder being provided. The inner electrode is preferably made of bundled stainless steel fibers with a fiber diameter of approximately 1.0 to 1.2 μm, preferably approximately 1.0 μm, wherein the length of the fibers is approximately 3 to 6 cm. When installed, the fibers predominantly overlap. The sieve cylinder is preferably made of a metal wire mesh, wherein the wire diameter is preferably between approximately 0.18 and 0.36 mm and the spacing of the longitudinal wires is preferably between approximately 0.4 and 1.25 mm.

[0031] The glass tube forms a dielectric in conjunction with the sieve cylinder as the outer electrode. With a glass tube material thickness of 0.18 to 0.36 mm and a spacing of 0.4 to 1.25 mm between the longitudinal wires and the inner electrode, which consists of bundled stainless steel filaments with a thickness of 1.0 to 1.2 μm, a particularly homogeneous dielectric discharge occurs.

[0032] During operation of the device, the discharge tubes convert the oxygen in the air in the hive into hydroxyl radicals. This effect is best achieved by applying high-energy alternating voltage pulses with a frequency of preferably 25 to 44 kHz.

[0033] Plasma power densities of the discharge area of ​​0.2 W / cm 2 up to 0.7 W / cm 2 , preferably 0.3 W / cm 2 up to 0.6 W / cm 2, also prevent the formation of unwanted ozone. Further preferred embodiments for generating a non-thermal plasma can, for example, be flat electrode arrangements of the plasma source or electrode arrangements designed in the form of a hollow tube with an axially aligned inlet for introducing a carrier gas into the tube and an axially aligned plasma outlet for discharging the non-thermal plasma from the tube, so that the plasma is generated within the tube. Glass materials, ceramics, or polymers are preferably used as the dielectric barrier.

[0034] The device for preventing the formation of Varroa mites or eliminating existing Varroa mites in a beehive comprises a plasma generation unit configured to generate a plasma. The introduction element is designed to safely introduce the plasma of the plasma generation unit into the beehive without disturbing the bees or the structure of the beehive. The plasma generation unit can be located inside the beehive in the introduction element or it can be located outside the beehive.

[0035] A power supply unit is provided to provide the necessary energy for the plasma generation unit. The plasma generation unit is designed to use a dielectric barrier discharge (DBD) to generate plasma at room temperature and atmospheric pressure.

[0036] This description is for illustrative purposes and is not intended to limit the scope of the invention as defined by the claims.

Claims

CLAIMS 1. A device for preventing the formation of Varroa mites or for eliminating existing Varroa mites in a beehive, comprising: a) a plasma generating unit having a plasma discharge area of ​​1.0 cm 2 up to 6.0 cm 2 , preferably 2.5 cm 2 up to 3.5 cm 2 wherein the plasma generation unit has a plasma outlet so that the plasma can be introduced into the hive, b) a control device which is connected to the plasma generation unit, wherein the control device is designed such that the plasma power density of the discharge area on the plasma generation unit is adjustable, wherein the plasma power density of the discharge area is set to 0.2 W / cm 2 up to 1.0 W / cm 2 , preferably 0.3 W / cm 2 up to 0.6 W / cm 2 is set.

2. Device according to claim 1, characterized in that the control device is designed such that it is possible to select between a first operating mode and a second operating mode, wherein with the plasma generation unit in the first operating mode a plasma power density of the discharge area of ​​0.2 W / cm 2 up to 0.45 W / cm 2 , preferably 0.3 W / cm 2 up to 0.45 W / cm 2 and in the second operating mode a plasma power density of the discharge area of ​​0.45 W / cm 2 up to 0.7 W / cm 2 , preferably 0.45 W / cm 2 up to 0.6 W / cm 2 can be submitted.

3. Device according to claim 2, characterized in that in the first operating mode the plasma is emitted continuously and in the second operating mode the plasma is emitted in bursts.

4. Device according to one of claims 1 to 3, characterized by a sensor for detecting the presence of Varroa mites in the hive, wherein the sensor is connected to the control device and wherein the control device activates the plasma generation unit in the presence of Varroa mites.

5. Device according to claim 4, characterized in that the sensor for detecting the presence of Varroa mites comprises a camera with image analysis function and / or infrared sensors.

6. Device according to one of claims 1 to 5, characterized in that the control device is designed such that when the sensor detects a presence of Varroa mites, the plasma generation unit is activated and regulated until the sensor registers a presence of Varroa mites below a threshold value.

7. Device according to one of claims 1 to 6, characterized in that the plasma outlet is arranged on an introduction element which can be introduced into the beehive.

8. Beehive with a drawer arranged on the underside, preferably a drawer, in which a device according to one of claims 1 to 7 is arranged.

9. A method for preventing the formation of Varroa mites or for eliminating existing Varroa mites in a beehive, comprising the steps of: a) introducing a plasma outlet for plasma of a plasma generation unit into a beehive; b) activating the plasma generation unit to generate a plasma with a plasma power density of the discharge area of ​​0.2 W / cm 2 up to 1.0 W / cm 2 , preferably 0.3 W / cm 2 up to 0.6 W / cm 2 .

10. Method according to claim 9, characterized in that with the plasma generation unit in the first operating mode, a plasma power density of the discharge area of ​​0.2 W / cm 2 up to 0.45 W / cm 2 , preferably 0.3 W / cm 2 up to 0.45 W / cm 2 and in the second operating mode a plasma power density of the discharge area of ​​0.45 W / cm 2 up to 0.7 W / cm 2 , preferably 0.45 W / cm 2 up to 0.6 W / cm 2 is delivered, preferably the second operating mode comprises a burst-like plasma delivery and the first operating mode comprises a continuous plasma delivery.