Heat treatment of the brood combs to control Varroa mites requires an expensive instrument and time.

The heat treatment method is not widely used and sufficient scientific studies are still lacking. However, various devices are already available on the market. Some heat treatments for Varroa control are carried out on the whole colony, while other systems treat individual brood combs.

The method is based on the different thermotolerance of honey bees and Varroa mites. The operculated brood can tolerate short-term heatings up to 44 °C, while the Varroa mite cannot tolerate temperature above 40 °C. There are two different options for heat treatment: either the brood combs can be removed and exposed to heat treatment, or sensors can be attached to the inside of the hives to treat individual colonies. In both cases, the temperature should be close to 44 °C and kept for a few hours to ensure that it warms up the Varroa mites possibly present in the brood cells over their thermotolerance limit. The possible negative effects on bees (e.g. life-span), have not yet been sufficiently investigated.

Warnings: May depend on the regulations in force in the given country.

Please check out the B-THENET Platform for the Best Beekeeping Practices tailored to each country, co-developed with practicing beekeepers in the National B-THENET Centres of those countries (Austria, Belgium, Croatia, Denmark, Germany, Greece, Hungary, Italy, Poland, Slovakia, Slovenia, Spain, Sweden). 

Queen caging is used to ensure an artificial brood block, both in summer and winter (when necessary).

Numerous queen caging devices are available on the market. The cant differ in size, materials used and relative cost. All such devices are equipped with a queen excluder net that prevents the queen from passing through, but ensures that the worker bees can take care of her.

On average, caging the queen takes longer than treating her with acaricides alone. There are cages made of different materials (e.g. bamboo or plastic) and with different space within the grid.

The two basic types of caging:

1. Caging separately from the frames (it does not allow ovideposition)
2. Caging on the frame (it allows ovideposition)

The duration of caging can be variable. The treatments (e.g. oxalic acid treatments) are carried out when all brood has either been removed and there is no receptive brood (in case of using cages that prevent the queen from oviposition) or all brood is removed but there is still receptive brood (in the case of using cages that allow the queen to oviposit).

Isolation with vertical queen excluders can also be mentioned, but the remaining brood must be removed.

Even in case of single-honeycomb caging, the single honeycomb also must be disposed due to the possibly high Varroa mite infestation level. In case of confinement on several combs, new nuclei can be established instead.

As an alternative to the honeycomb cage, a super frame can be used on which the queen excluder is mounted on both sides. The wax sheet can be left unbuilt, but it would be better to remove it completely to allow the bees to pass through and to ensure greater diffusion of the queen's pheromone.

With respect to the positioning of the cage on the frame in summer/winter, the geolocation is also important to be considered (e.g. in summer at high altitudes it might be better to place the cage higher up).

The queen can also be confined for a shorter period of time, restarting the egg-laying activity a few days earlier, allowing a faster recovery for the hive and less stress for the queen. The Varroa mite, in fact, enters the brood cells just before their closing, i.e. on day 9 after oviposition. Therefore, it is possible to release the queen 7 days earlier than the theoretical 24 days, i.e. on day 17. In fact, even assuming that as soon as the queen is released, it begins to lay eggs, the larvae will only be receptive for Varroa mite infestation after 8-9 days, however, in the meantime all the operculated cells present will be hatched. In this way, we can shorten the queen caging period by a week, allowing oviposition to resume earlier, resulting in a faster recovery of the hive. Even if the queen is freed on day 17, anti-varroa treatment must be carried out on day 21 or (in case drone brood is present) on day 24 from the onset of queen caging.

In case of winter caging, the cage containing the queen should remain inside the glomere at all times. In winter, the caging period can be even longer than 24 days and the queen can be released when environmental conditions are favourable for the development of the colony. One strategy for caging the queen during winter is to place the cage above the frames so that the bees can take care of the queen and keep her at a suitable temperature more easily (the heat developed by the hive is streaming upwards).

Conversely, in case of summer caging, the cage containing the queen should be placed on the lower part of the frame, preferably near the hive entrance to ensure optimal ventilation.

Caging on honeycombs can also be performed by placing the frame inside the hive cover.

As observed by beekeepers, the re-acceptance of queens on honeycomb, in summer is higher than that of caged queens. In some cases, honeycomb mortality is lower than cage mortality. Based on field experience, queens that die in cages are assumed to have a priori problems (e.g. low fertility, low pheromone production).

A new alternative to queen caging for brood blocking is the ringing of queens. This technique involves the use of plastic or silicone rings that are placed around the queen's abdomen. These rings prevent the queen from oviposition.

Warnings: May depend on the regulations in force in the given country.

Please check out the B-THENET Platform for the Best Beekeeping Practices tailored to each country, co-developed with practicing beekeepers in the National B-THENET Centres of those countries (Austria, Belgium, Croatia, Denmark, Germany, Greece, Hungary, Italy, Poland, Slovakia, Slovenia, Spain, Sweden). 

Brood removal is a beekeeping technique to remove the brood present to increase the effectiveness of acaricide treatments (e.g. oxalic acid) in the foretic phase.

Tools and materials needed:

The active ingredients that are considered to have a low environmental impact (e.g. thymol, menthol, camphor etc.) might vary among the countries.

Only veterinary medicinal products authorized in the given country should be applied.

Warnings: May depend on the regulations in force in the given country.

Please check out the B-THENET Platform for the Best Beekeeping Practices tailored to each country, co-developed with practicing beekeepers in the National B-THENET Centres of those countries (Austria, Belgium, Croatia, Denmark, Germany, Greece, Hungary, Italy, Poland, Slovakia, Slovenia, Spain, Sweden). 

Thymol is an active ingredient that is able to kill Varroa mites only outside the brood cells.

However, thymol-based veterinary medicinal products can also be used in the presence of brood, administering them at the times indicated in the package leaflets. Thymol is a natural active ingredient and permitted in organic beekeeping (please also check out the relevant national legislation).

Thymol spreads by evaporation and the rate of evaporation is influenced by the temperature outside the hive. In case of high ambiental temperature, the evaporation rate might be too fast, which can cause even serious damage to hives (absconding). If such temperature is too low, the evaporation speed may be too low thus hindering the efficacy of the treatment.

The instructions given in the information leaflet of the veterinary medicinal product must be followed carefully.

Thymol-based veterinary medical products are generally not suitable for winter treatment.

Since thymol acts by evaporation, it is more effective in densely populated hives having good ventilation and thus better diffusion of the active ingredient within the hive. Therefore, during the treatment with thymol, the mesh bottom of the hives as well as any gaps (e.g. the space between the coverlet and the nest) must be closed to prevent dispersion of the active ingredient, which could reduce the efficacy of the treatment.

To allow the bees to get used to the thymol treatment, it can be started the evening before by applyng a reduced dosage.

Warnings: May depend on the regulations in force in the given country.

Please check out the B-THENET Platform for the Best Beekeeping Practices tailored to each country, co-developed with practicing beekeepers in the National B-THENET Centres of those countries (Austria, Belgium, Croatia, Denmark, Germany, Greece, Hungary, Italy, Poland, Slovakia, Slovenia, Spain, Sweden). 

Formic acid is an active ingredient that can kill Varroa mites even within the brood.

Evaporation of formic acid is influenced by temperature. High temperatures may lead to an evaporation rate that is too fast, which may cause damage, even serious, to the hives (absconding, death of adult bees, brood, orphan colonies). Conversely, in case of low ambient temperature, the evaporation speed may be too low which can drastically reduce the effectiveness of the treatment.

The indications given in the information leaflet of the veterinary medicinal product applied must be followed carefully.

The colony strength can determine the success (or failure) of the treatment: in densely populated hives with good ventilation the diffusion of the active ingredient inside the hive is better.

Since formic acid is spread by evaporation, it is necessary to close the mesh bottom of the hives to prevent the dispersion of the active ingredient, which could reduce the effecicay of the treatment. However, removing the flight hatch to facilitate ventilation by the bees in case of high temperature might be advisable.

Some formic acid drugs require specific devices for administration.

Warnings: May depend on the regulations in force in the given country.

Please check out the B-THENET Platform for the Best Beekeeping Practices tailored to each country, co-developed with practicing beekeepers in the National B-THENET Centres of those countries (Austria, Belgium, Croatia, Denmark, Germany, Greece, Hungary, Italy, Poland, Slovakia, Slovenia, Spain, Sweden). 

Oxalic acid is an active ingredient that can only kill Varroa mites present outside the operculated cells. Therefore, the anti-varroa treatments carried out with products containing oxalic acid as active ingredient must be applied in the complete absence of operculated brood.

The factors to be considered in casse of oxalic acid treatments:

Anti-varroa treatments are necessary to ensure the survival of hives, their health, and productivity.

For the selection of the best time period for anti-varroa treatments the following aspects must be considered:

Knowing the level of Varroa infestation is fundamental for all beekeepers, both hobbyists and professionals, as Varroa mite is still the main cause of mortality of bees all over the world.

The main possible components of assessing the Varroa mite infestation level:

Theft of both hives and full supers is an increasingly frequent phenomenon that needs to be tackled.

The main type of tools and devices available commercially for preventing hive thefts:

Maintaining an adequate distance between apiaries is important for management and health issues.

Regarding the distances between apiaries, it is important to specify whether we are referring to the distances between the apiaries of the same beekeeper or the distances between the apiaries of different beekeepers.

For apiaries belonging to the same beekeeper, it is recommended to have a distance of at least 3 km among the apiaries. In this way, the bees of one apiary will not be in contact with those of other apiaries and also it is possible to move hives or nuclei between one apiary and another without the risk of the foragers returning to their initial position. Furthermore, in the event of diseases or cases of parasitic re-infestations it is possible to intervene or isolate only the apiaries affected, while if they were less than 3 km away it would be necessary to intervene or isolate all those within a 3 km radius of the apiary having health issues.

For the distances between apiaries of different beekeepers, the national legislation can provide a mandatory minimum distance.

Another aspect linked to the distance from other apiaries is productivity (based on the season, flowering, etc.). Maintaining active communication with the neighbouring beekeepers is always important. Abandoned apiaries or those not bearing the registration code can be reported (based on the national legislation). It is also important to consider the geographical qualities of the foraging territory (for example, a pasture between two slopes compared to one on the plain). The distance among small apiaries should also be considered (e.g. many small apiaries close to each other can still create a bigger problem compared to two large apiaries set-up at larger distances apart). Veterinary associations and official veterinary services can disseminate disease prevention and treatment protocols for apiaries, especially in areas with a high density of apiaries. To guarantee genetic isolation, greater distances (even greater than 10 km) between two apiaries could be advantageous.

Warnings: May depend on the regulations in force in the given country.

Please check out the B-THENET Platform for the Best Beekeeping Practices tailored to each country, co-developed with practicing beekeepers in the National B-THENET Centres of those countries (Austria, Belgium, Croatia, Denmark, Germany, Greece, Hungary, Italy, Poland, Slovakia, Slovenia, Spain, Sweden).

Areas exposed to humidity or excessive wind shoudl be avoided for the apiary.

Excessive humidity and wind are poorly tolerated by bees and can favor the onset or worsening of honey bee diseases such as nosemosis or mycosis. To avoid excess humidity, it is important to avoid extremely shaded areas and areas where fog persists. Excess wind can drastically reduce the flying and foraging activity of bees, as well as the productivity and well-being of the honey bees. Furthermore, strong wind can uncover or even overturn the hives or swarm carriers. To reduce the impact of the wind, the area should be well known and mapped, and advantage must be taken from the wood patches and tree-lined areas that can protect the hives from the stronger wind blow.

Placing the hives in areas with wood can be useful to reduce the effect of the wind, but in autumn and winter there should not be excessive humidity. It is important not to place the hives directly on the ground. This is both to prevent the wood from being damaged and to prevent humidity from entering the hive. It is important that the hives are of good quality and well maintained to avoid water infiltration (and ensure adequate thermal insulation). If possible, increase the roof covering to reduce the possibility of the external side walls of the hive getting wet. Avoid placing hives near watercourses and wetlands (e.g. lakes, ponds, etc.) and depression areas. It is important to make an on-site assessment to understand: the altitude of the terrain, any wind barriers present (or what kind of such barriers can be set up), the trend of the prevailing winds, and to reduce the exposure of the bees to the latter.

Warnings: May depend on the regulations in force in the given country.

Please check out the B-THENET Platform for the Best Beekeeping Practices tailored to each country, co-developed with practicing beekeepers in the National B-THENET Centres of those countries (Austria, Belgium, Croatia, Denmark, Germany, Greece, Hungary, Italy, Poland, Slovakia, Slovenia, Spain, Sweden).

Bees can collect nectars or pollen which can have allergenic or toxic effects on people.

In certain countries, this problem mainly concerns the collection and production of pollen. Pollen collected by bees can trigger allergic reactions in people sensitive to the given allergen if inhaled or ingested. In this case placing bees for pollen production in areas where plants that most frequently cause allergic reactions are present (such as parietaria, cypress, hornbeam, goldenrod, sunflower, etc.) should be avoided. However, there could also be accidental contamination. For pollen allergies, it is essential to inform the consumer that the intake of bee pollen can trigger allergic reactions in sensitive individuals. As regards toxic plants, the greatest risk is the presence of pyrrolizidine alkaloids in the pollen. Such alkaloids can be found in plants of botanical families such as: Boraginaceae, Asteraceae, Orchidaceae, and Leguminosae, less frequently in Convolvulaceae and Poaceae, and in at least one species of the Lamiaceae. Another toxic plant is the rhododendron. It is advisable to avoid areas with a high presence of these plants and to carry out laboratory analyzes to search for pyrrolizidine alkaloids in the final honey product.

Warnings: May depend on the regulations in force in the given country.

Please check out the B-THENET Platform for the Best Beekeeping Practices tailored to each country, co-developed with practicing beekeepers in the National B-THENET Centres of those countries (Austria, Belgium, Croatia, Denmark, Germany, Greece, Hungary, Italy, Poland, Slovakia, Slovenia, Spain, Sweden).

The accessibility of the apiary with vehicles is crucial for the efficiency of the beekeeper's work and to ensure timely intervention in the hives when needed.

All apiaries should be easily accessible with vehicles in all seasons of the year.

The advantages of the accessibility are numerous:

Avoiding exposure to pollutants is crucial both for the well-being and survival of the hives and for the quality of the bee products.

The main sources of contamination are undoubtedly the phytosanitary treatments carried out in agriculture. This is why it is essential to know the area around the apiary in order to assess whether there are crops that are likely or certain to need treatment, evaluating whether the apiary should be set up there and if so, whether there are times when it needs to be relocated. The most dangerous active ingredients in terms of toxicity to bees are insecticide and acaricide treatments, but fungicide and herbicide treatments can also have a detrimental effect on the hives.

To avoid industrial pollution, the apiaries should not be installed apiaries near industrial plants, incinerators and landfills.

Pollution caused by busy roads appears to be less impactful on the quality of bee products than other forms of pollution and contamination. However, it is advisable not to place bees near such roads to avoid the risks of collision with vehicles that might lead to a high mortality of foraging bees. It would be advisable, in such cases, to provide hedges or obstacles to avoid direct collision of bees with high-speed vehicles on particularly busy roads such as freeways/highways.

One of the main sources of the contamination and intoxication occurring in the apiaries is the use of pesticides. It is always necessary to be aware of the pesticides used in the vicinity of the apiary and the times when treatments are carried out on crops.

Fungicides and herbicides can also dangerous for the bees (chronic poisoning).

Assessing the area around the apiary (also by means of ortophotos available on the internet) is important for evaluating possible sources of pollution.

Please note that the responsibility for the quality and healthiness of hive products lies with the beekeeper.

In case of apiaries where the bees might come into contact with pesticides, a regular communication about the pesticide and other treatments should be established between the beekeepers and the farmers. When needed, appropriate actions such as closing or moving hives should be taken. However, the optimal solution is avoiding the vicinity of conventional agriculture when setting up an apiary.

When abnormal mortality of the bees occur, notify the official veterinary services of the local health authority.

Insecticide treatments carried out in residential, urban and peri-urban areas to control mosquitoes should also be considered. These treatments are linked to the local regulations.
It should be borne in mind that apartment blocks and private individuals also often use mosquito repellents.

Warnings: May depend on the regulations in force in the given country.

Please check out the B-THENET Platform for the Best Beekeeping Practices tailored to each country, co-developed with practicing beekeepers in the National B-THENET Centres of those countries (Austria, Belgium, Croatia, Denmark, Germany, Greece, Hungary, Italy, Poland, Slovakia, Slovenia, Spain, Sweden).

Maintaining an adequate number of hives is important for proper management of beekeeping activities and for high quality and efficiency of work.

The appropriate number of hives may vary from person to person and from farm to farm and must take into account

Maintaining a safe distance from houses and villages or to use devices that minimise risks to people is indispensable in beekeeping.

People should be prevented from passing or interfering with the flight paths of bees.

The national law might set a minimum distance between the hives and the from borders of any other properties.

These provisions also apply in the case of urban beekeeping. A hive can therefore hardly be placed on a balcony (because it is too close to other apartments or offices), whereas it might be placed on the roof -  all in accordance with the national legislation.

The national regulations might also set a minimum distance for hives from sugar refineries. For keeping that distance, the nectar flow around the apiary must be evaluated because if there is a shortage in nectars during the season, the bees might forage at greater distances and can reach the sugar refinery. Placing the apiary minimum 4-5 km away from the sugar refinery might decrease the possibility of bees foraging in the area of the industrial plant.

To guarantee adequate safety not only the minimal distances should be considered: the usual use of the surroundings of the apiary must also be assessed to avoid the risk of even accidental contact with flying bees.

In addition to the physical safety of people, other aspects of the vicinity of an apiary must be also taken into consideration:

Having adequate space (warehouses, canopies) for storage and working tools is necessary for efficient work.

The storage volume shoudl be calculated considering:

Trees can be valuable for the prevention of atmospheric stress on the bee hives.

In particular, they can:

-provide protection from prevailing winds, and

-provide shade in summer.

Forest patches, rows of trees or even hedges can be used for protection from prevailing wind, provided they are of a certain height (at least 3 metres). The presence of areas with wooded patches or strips makes it possible not only to directly protect the hives from the risk of overhanging or toppling over, but also to guarantee protected flying spaces even in case of strong wind.

Shading in summer can be very important for two goals: reducing the need for ventilation and thus saving work and honey consumption, and guaranteeing safer situations for antivarroa treatments with evaporating active ingredients such as thymol and formic acid. In summer, the shade of the trees is an advantage for both bees and beekeepers.

In any case, it is good to ensure that the presence of trees does not create conditions of excessive shade and humidity in winter and spring. For this reason, deciduous trees are preferable to evergreen ones in the case of stationary apiaries.

It is obviously important to be sure of the stability of these trees to prevent them from falling and causing damage to the hives or the people working under them.

Particular attention should be paid to breeding nuclei as such colonies have greater difficulty in thermoregulating.

In sedentary apiaries (maximum 50 hives), wood/iron structures could be built inexpensively (e.g. from bamboo fence panels).

Warnings: May depend on the regulations in force in the given country.

Please check out the B-THENET Platform for the Best Beekeeping Practices tailored to each country, co-developed with practicing beekeepers in the National B-THENET Centres of those countries (Austria, Belgium, Croatia, Denmark, Germany, Greece, Hungary, Italy, Poland, Slovakia, Slovenia, Spain, Sweden).

It is important to avoid obstacles that make it difficult or troublesome to fly for the bees.

The grass and vegetation around the hive should be cut short (always while using appropriate personal protection), so that it does not obstruct the hive opening and prevents or makes it difficult for foraging bees to enter and exit the hive.

Bees must avoid crossing busy roads or railways to avoid the risk of impact with vehicles. If necessary, it is important that the bees cross these areas at a flight height that ensures safety. This can be done by putting up a physical barrier (hedge, wall, cloth, etc.) that forces the bees to fly upwards and reach a safe height before flying over the road.

Avoid installing hives in very windy areas: strong wind prevents flight activity. If this is not possible, install 'green' barriers to protect the apiary from wind exposure.

Tall grass in front of the hive entrance can, however, bring several advantages: reduction of drift and looting, reduction of wasp attack, and partial protection from the wind. Reduce the strip of tall grass in front of the hives to a minimum (to avoid fires, etc.).

Warnings: May depend on the regulations in force in the given country.

Please check out the B-THENET Platform for the Best Beekeeping Practices tailored to each country, co-developed with practicing beekeepers in the National B-THENET Centres of those countries (Austria, Belgium, Croatia, Denmark, Germany, Greece, Hungary, Italy, Poland, Slovakia, Slovenia, Spain, Sweden).

The correct positioning of the hive is important for the activity and well-being of the bees and for the quality and efficiency of the beekeeper's work.

For the activity and well-being of bees, the hive must be positioned on an even and stable surface so as to avoid the risk of tipping, and the opening of the hives should face south, if possible.

For the safety of the beekeeper, the hives should be placed as high as it is comfortable for the beekeeper: hive management should be possible without bending over the hives and the lifting of the hives should be possible with the smallest possible movement.

On average, if the hive is placed 40-50 cm high, both moisture originatng from the ground and the entering of small reptiles, beetles, or mice can be prevented.

Iron, wood or concrete posts can be used for supports. Each material has its advantages and disadvantages:

ADVANTAGES
Iron: practical (single structure), light, cheap
Wood: sustainable, non-slip, lightweight
Cement: economical (vineyard poles), non-slip

DISADVANTAGES
Iron: possible slipping of hives, vibration, painting, thermal conductivity
Wood: cost, maintenance (deterioration)
Cement: heavy

The suitability of the materials used should be assessed on a case-by-case basis, taking into consideration also the total wight of the final structure.

Using a spirit level to adjust the base is important to prevent the hives from tipping over, especially when there are many honeycombs that can cause unbalance. If the hive is slightly tilted forwards, the condensation water can evaporate more easily. Position the hives so that the flight direction of the bees does not interfere with the passage of agricultural vehicles or people. The base of the supports must rest on stable, solid ground and/or should be sufficiently wide.

Warnings: May depend on the regulations in force in the given country.

Please check out the B-THENET Platform for the Best Beekeeping Practices tailored to each country, co-developed with practicing beekeepers in the National B-THENET Centres of those countries (Austria, Belgium, Croatia, Denmark, Germany, Greece, Hungary, Italy, Poland, Slovakia, Slovenia, Spain, Sweden).

Seasonal relocation of the apiary might be useful or necessary to achieve higher production, ensure better overwintering, guarantee better hive development, and avoid phytosanitary treatments.

For the relocation of the apiaries, the following factors must be considered:

1. Means of transport (trucks, vans, pick-ups, trailers)
2. Lifting equipment (forklifts, hydraulic platforms, cranes)
3. Hives with efficient closures and large ventilation areas

The new site should be chosen according to the various needs within the apiary. E.g., to obtain greater production, a site with an abundance of nectariferous and/or polleniferous blooms should be identified. For better wintering, the site should be sunny, with low humidity, possibly with minimum temperatures that are not excessively cold, and easily accessible in all weather conditions. For better hive or nucleus development, it is important to have a site rich in pollen and also nectar, having mild temperature in spring and not excessively hot and dry in summer. To avoid phytosanitary treatments, the new site should be far from agricultural crop fields, or else, those crops should not require such treatments at that time.

Preparation of hives for the relocation: the hives must be closed to prevent the bees from getting out, but, at the same time, should have large ventilation surfaces to ensure heat dispersion and the passage of air, therefore, removing the sheet metal at the bottom of the hive during hot periods might be advantageous. Hives must be closed when there is no flying activity, i.e. in dark or in case pf rainfalls.

Tips for closing the hives: turn the cover over, tape it shut, place the three-position disc in 'net' mode, do not place the cover, use jack straps and rope between the handles on the outside of the load.

Means of transfer: Trucks, pick-ups, and tow trucks can be used. Closed vehicles such as vans or tarpaulin trucks might also be used. Pallets, cranes, and moving walkways can be used to facilitate the loading and unloading of the hives. In the case of transport with a tarpaulin truck (well-closed), the hives can be kept open to avoid overheating.

Time and mode of travel: The transfer should be done as quickly as possible to reduce the stress for the hives. During th etransfer, breaks should be avoided, unless inevitable.

Warnings: May depend on the regulations in force in the given country.

Please check out the B-THENET Platform for the Best Beekeeping Practices tailored to each country, co-developed with practicing beekeepers in the National B-THENET Centres of those countries (Austria, Belgium, Croatia, Denmark, Germany, Greece, Hungary, Italy, Poland, Slovakia, Slovenia, Spain, Sweden).