DISPENSER FOR FORMIC ACID VAPOUR AND METHOD FOR MITE CONTROL IN BEEHIVES

Abstract

A dispenser is disclosed. In one example, the dispenser relates to the distribution of formic acid vapour in beehives to combat mites. The dispenser has an evaporation surface which is delimited by a thin, gas-permeable, highly porous membrane made from a hydrophobic material and comprises an evaporation container and a reservoir, for the treatment dose of a liquid formic acid preparation. The evaporation container can be placed in a narrow air space of the hive, for example a comb space. The evaporation surface is exposed in a comb space of the brood nest or an air flow path. In one embodiment, the dispenser is equipped with a stackable packaging, and the treatment dose of the formic acid preparation is located exclusively in the hermetically sealed reservoir. The dispenser allows a very high evaporation rate per unit area and can be used without spatially extending the hive.

Claims

1. A dispenser for receiving and evaporating a liquid formic acid preparation for combating varroa mites in a bee hive, comprising a gas-permeable liquid barrier in the form of a porous membrane impermeable to liquid mixtures of formic acid and water for dispensing formic acid vapour, further comprising: an evaporation container with dimensions suitable for insertion into an air-flowing honeycomb alley leading through the brood nest or for placing on upper beams of honeycomb frames of the brood nest without spatial extension of the hive by an empty frame, an additional empty frame or the like; a storage container connected to the evaporation container and sealed from the outside in a vapour-tight manner for storing the entire treatment dose of a liquid formic acid preparation until the time of formic acid treatment; a closable liquid-conducting connection between the storage container and the evaporation container for transferring the liquid formic acid preparation from the storage container to the evaporation container; and a gas-permeable, fine-pored membrane with a solids content of less than 70% and continuous, exclusively gas-filled pores with a width of between 10 nm and 1000 nm as part of the outer boundary of the evaporation container, which membrane is liquid-tight during the treatment period under the dynamic pressure of a liquid formic acid preparation and adjoins the space through which gas flows in one or more honeycomb alleys or a channel integrated in the evaporation container and leading through the honeycomb alleys.

2. The dispenser according to claim 1, comprising: an evaporation container for placing on a plurality of upper supports of the honeycomb frames in a hive; a closed film bag formed of polyethylene, polypropylene or other flexible, liquid-tight, weldable polymer resistant to formic acid; a sealing outer removable clamp separating the interior of the film bag into two formic acid preparation containers, the storage container and the evaporation container; and a liquid-impermeable and gas-permeable membrane forming the underside of the evaporation container or part thereof.

3. The dispenser according to claim 1, having an inner skeleton in the evaporation container for ensuring the flow of the liquid formic acid preparation onto the gas-permeable membrane.

4. The dispenser according to claim 1, comprising a stackable package and a sealed connection between the storage container and the evaporation container which opens when the evaporation container is removed from its package.

5. The dispenser according to claim 1, having an evaporation surface area of less than 30 cm.sup.2.

6. A method of treating a bee colony with formic acid vapour by means of the dispenser of claim 1, characterized by positioning the evaporation container in an air space of the hive without expanding it spatially and without using an empty honeycomb frame, comprising: bringing the evaporation container into close heat-conducting relationship with the brood nest combs; placing the evaporation surface under the dynamic pressure of the treatment dose of the liquid formic acid preparation; and exposing the membrane-limited evaporation surface is exposed in the air-flow space of one or more honeycomb alleys in the brood nest area.

7. The method according to claim 6, comprising placing the evaporation container in a honeycomb alley of the brood nest or in a space bounded by brood nest honeycombs.

8. The method according to claim 6, in which, prior to the construction of the brood combs, a space provided for receiving the evaporation container or the entire dispenser between the honeycomb frames is filled by a placeholder or hollow receiving body, or the evaporation container or the dispenser is already placed in the brood nest prior to the construction of the brood combs.

9. The method according to claim 6, comprising placing wherein a treatment dose reservoir connected to the evaporation container is placed outside the hive.

10. The method according to claim 6, comprising placing wherein a flatly spread storage container fitting under the lid of the hive or between two frames without spatial extension of the hive is placed on the honeycomb frames of the hive.

11. The method according to claim 10, wherein the evaporation container is placed on the honeycomb frames in such a way that the gas-permeable liquid barrier is exposed in several honeycomb alleys in the brood nest area.

12. The method according to claim 10, comprising covering the evaporation container is covered by a heat insulating layer.

Description

DESCRIPTION OF THE FIGURES

[0024] FIG. 1 schematically shows a dispenser whose evaporation container 1 (bottom) is connected to a storage container 2 (top). The evaporation container is located in the honeycomb alley 3 into which it exposes the evaporation surface 4 bounded by the gas-permeable liquid barrier. The evaporation container is connected to the storage container, a shallow container with a capacity of about 120 cm.sup.3 and a base area of about 200 cm.sup.2, by a connecting pipe 5. The entire treatment dose of the liquid formic acid preparation is in the gas-tight sealed storage container before treatment. To start the formic acid vapour treatment, the liquid formic acid preparation is fed into the evaporation container by opening the clamp 6.

[0025] FIG. 2 shows schematically an evaporation container which is placed on the honeycomb frames 11 and covered by a heat-insulating layer 7.

[0026] Top: Top view of the honeycomb frames, the honeycomb alleys and the evaporation container. The evaporation surface bounded by the gas-permeable liquid barrier rests on the upper beams 12 of the honeycomb frames and is exposed to the air space of the honeycomb alleys of the brood nest. Below: Section of a cross-section through the evaporation container perpendicular to the course of the honeycomb frames.

[0027] FIG. 3 shows a schematic view of a section through two honeycomb frames with evaporation containers with different positions of the evaporation surfaces, which are bordered by a gas-permeable liquid barrier. Top: The evaporation container has been placed in the honeycomb alley to treat the hive and exposes two evaporation surfaces to the honeycomb alley. Spacers 13 ensure a defined airflow path and good heat conduction and prevent the evaporation windows from contacting the combs. Centre: The evaporation container was placed in the space between the centre walls 14 of two honeycomb frames before the honeycombs were built. It adjoins the combs of both frames during the treatment period and encloses an airflow path 8 through the brood nest, separated from the honeycomb alley. Below: The evaporation container has an integrated air flow path, a flexible outer wall impermeable to formic acid vapour and a flexible inner wall in which the evaporation surface is integrated. In the position of the evaporation surface, the inner wall is formed by a gas-permeable liquid barrier. The evaporation container contains an elastic screen fabric 9 made of polystyrene to ensure the distance between the outer and inner walls and to guarantee elasticity.

[0028] FIG. 4 shows in schematic view a longitudinal section through a dispenser according to the invention with a clamping device which opens when the evaporation container is removed from the packaging 10. Top: For storage of the dispenser before use, the connecting pipe 5 between the storage container 2 and the evaporation container 1 is tightly clamped with a clamp 6. The liquid formic acid preparation is only in the storage container and the part of the connecting pipe that lies between the clamp and the storage container. The clamp prevents the formic acid preparation from being transferred to the evaporation container. Below: By pulling the evaporation container out of the packaging, the connecting line has been stretched and pulled out of the clamp. The formic acid preparation can be transferred into the evaporation container through the thus opened connecting pipe. This process can be supported by mechanical pressure on the flexible wall of the storage container.

[0029] FIG. 5 shows a schematic view of a dispenser according to the invention, in which the outer shell of the evaporation container and the storage container are formed by a liquid-tight, sealed foil bag 15. The dispenser is shown in view of the underside with the gas-permeable membrane inserted into a window in the outer shell, which forms the evaporation surface. The storage container 2 is separated from the evaporation container by the clamping device 16. It is filled with the liquid formic acid preparation before the dispenser is placed. In the evaporation container 1 there is an inner skeleton 17 in the form of a grid to ensure wetting of the gas-permeable membrane in the evaporation container spread flat until the liquid phase is almost completely evaporated.

LIST OF REFERENCE SIGNS

[0030] 1 Evaporation container [0031] 2 Storage container [0032] 3 Honeycomb alley [0033] 4 Evaporation surface [0034] 5 Connecting pipe [0035] 6 Clamp [0036] 7 Heat insulating layer [0037] 8 Air flow path [0038] 9 Elastic screen fabric [0039] 10 Packing [0040] 11 Honeycomb frame [0041] 12 Top beam [0042] 13 Spacer [0043] 14 Centre wall [0044] 15 Foil bag [0045] 16 Clamping device [0046] 17 Inner skeleton

LIST OF CITED NON-PATENT LITERATURE

[0047] Amrine J, Noel R (2006): Formic acid fumigator for controlling varroa mites in honey bee hives, International Journal of Acarology, DOI: 10.1080/01647950608684452. [0048] Aumeier P, von der Ohe W, Beinert P, Kirchner W (2011): Use MAQS® wisely! ADIZ Die Biene-Imkerfreund May 2015, p. 12-13 [0049] Charrière J-D (1998): Five formic acid dispensers compared, www.imkerverband-sgap.ch/up/files/DispenserVergleich_Agro-scope1998.pdf [0050] Daniels R S, Abdulkareem H, Roger R E L, MacKenzie K (1999): Membrane-barrier delivery of formic acid, a chemical used for mite control in honey bees (Apis mellifera). Journal of Apicultural Research 38, 63-69 [0051] Johnsen B K (1954): On the influence of salt additives on the phase equilibrium of aqueous formic acid, e-collection.library.ethz.ch/eserv/eth:32505/eth-32505-02.pdf. [0052] Liebig G: Einfach imkern—Leitfaden zum Bienenhalten, Verlag Dr. G. Liebig, Emscherstr. 3, Bochum, 3rd ed. Aichtal 2011