| Cross-Contamination of Colonies
Honeybee colonies are subject to infestation and/or infection by a range of pests and diseases and, being social insects, colonies grouped together in an apiary are at risk of epidemics transferring from hive to hive.
Threats to the colonies and apiary as a whole include invasion by insects and mites, such as Varroa destructor, and the establishment of fungi, viruses, and bacteria, such as the microbes that cause American and European foulbrood (AFB and EFB).
A key factor in preventing the spread of infection and parasitic invasion is good housekeeping and hygiene applied across all apiary activities, including as a matter of regular routine decontamination and sterilisation of the hives, honeycomb frames and tools, including-
Sterilisation with Disinfectants
Timber brood boxes, supers and other beekeeping hardware can be effectively sterilised using disinfectants containing sodium hypochlorite that is present at a concentration of about 3% in household bleach.
Immersion for around twenty minutes in a solution of 0.5% sodium hypochlorite kills AFB spores and other bacteria - this concentration is a solution of one part household bleach to five parts water. It is essential that the spores are in contact with the solution, so any items immersed must be thoroughly cleaned before immersion.
Varroa Destructor Treatment with Oxalic Acid
Colonies infested with V. destructor may be treated with oxalic acid by Trickling, Spraying, and Sublimation.
Trickling and spraying the OA is applied in solution with both techniques requiring the hive to be opened.
For sublimation, the ambient temperature should be low (<5oC) with the bees tightly clustering within the hive are dosed with OA (as a dihydrate C2H2O4·2H2O). Particularly important is that this technique is applied when the Queen has stopped laying so the V. destructor mites are hosting externally on the bees (ie in the ectoparasite phase or phoretic state).
The OA crystals (in the form of pre-prepared tablets) are vaporised on a heated poker platen that is inserted into the hive entrance. The OA crystals sublimate (turn directly from solid to gas) and then condense on the bee cluster, with the outer layer of bees carrying the OA into the depths of the cluster thus exposing the mites.
Before starting the process, scrape out any dead bees on the hive floor using and appropriately fashioned wire coat hanger or similar. Then, to apply vaporisation, you need the applicator poker; a vehicle 12v battery to power the applicator; 2 OA dihydrate tablets); plastic foam or cloth to temporarily seal the hive entrance around the applicator; and the base monitoring board inserted to further seal the hive.
One advantage of sublimation over, particularly, trickling OA is that the droplet size is very small so as it condenses on the bee's exoskeleton there is less potential for damage to the carapace - in cold weather when the bees are clustered within the hive, the perpetual rotation of the bees on the outer cluster to within disperses and dilutes the OA effect thereby lessening the damge to the bees.
Sterilisation with Acetic Acid
Combs and hive timber components can be sterilised to destroy the spores of chalkbrood, wax moth eggs, and Nosema by using the evaporation fumes from acetic acid, although this treatment is not believed to be effective against AFB or EFB.
Finally, seal the assembly and acetic acid bath in a polythene sheeted wrap with a roof on top, and leave for about one week with a HazChem notice warning of the acetic acid fumes.
When the acetic acid sterilisation is over, air the frames and brood/super boxes for a couple of days before use - since acetic acid is corrosive check any metal fasteners and rails before returning the equipment to service. Do not include the V. destructor gauze bases in the acetic acid sterilisation stack.
Sterilisation using washing Soda crystals
Beekeeping tools and equipment (eg smokers and hive tools) can be cleaned using a solution of Sodium Carbonate (washing soda crystals).
The appropriate solution strength is 1 kg of washing soda to 5 liters of warm water with a dash of washing up liquid to help clean off propolis. Immerse the equipment in the solution, while using a wired brush, or similar tool to scrub off residues until the tools are clean.
Between hives and apiary working sessions, tool and glove surfaces can be sterilised by using 1:5 bleach-water solution sprayed on and wiped dry before use.
De-Infestation by Freezing
Wax moth infestation (eggs, larvae and pupae) can be purged by placing the hive chambers and honeycomb frames in a domestic chest freezer at -20oC for 48 hours.
This means of de-infestation should be carried out before the equipment goes into overwinter storage and again before going back on the hives for the foraging season. To inhibit re-infestation whilst in storage the brood and super boxes containing honeycomb frames should be sealed in a breathable fleece to avoid mould growth.
Scorching with a Blow torch
Sterilise timber components and hive parts (but not honeycomb frames, polystyrene hives, etc) by passing a blow torch flame over the surface and, particularly, along seams and cracks in the timberwork.
Note that because of the risk of cross-contamination issues secondhand and/or used equipment is not permitted in the Apiary - if you keep or access bees elsewhere other than at the Oxleas Wood Apiary, then you must use fresh tools, bee suit, etc., when working in the Oxleas Wood Apiary.
Similarly, bee colonies and Queens must be sourced from approved suppliers and collected swarms are not permitted into the Apiary without the express approval of the Oxleas Wood Apiary apiarist.