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  1. Pollinating Highbush Blueberries

    Investment in this critical component of blueberry production is essential for profitable yields

    Pollinating Highbush Blueberries

    Investment in this critical component of blueberry production is essential for profitable yields

    Rufus Isaacs, Jason Gibbs, Emily May
    Department of Entomology, Michigan State University

    Eric Hanson and Jim Hancock
    Department of Horticulture, Michigan State University

     

    Northern highbush blueberries (Vaccinium corymbosum) are common throughout the northern U.S. states and Canada, and are native to eastern North America. They require pollination to ensure that flowers present at bloom turn into large, harvestable berries later in the season. Pollination is achieved by the movement of pollen by bees.

    By planning ahead for how fields will be pollinated, growers can help ensure they receive the maximum return on their investments in land, bushes, and other management inputs. Given the high per-acre input costs of blueberry production, spending money to ensure high levels of pollination makes sound business sense. Other things being equal, well-pollinated fields have larger berries, higher yields, and more even ripening than fields with sub-optimal pollination.

    Across Michigan’s blueberry industry, most pollination is by managed honey bees that are brought to fields in hives. Many of these colonies have been overwintered in warmer states, and they arrive back in Michigan as fruit crops start blooming in southwest Michigan. Bumble bee colonies can also be purchased for placement in fields, and there are many other wild bee species that nest in and around crop fields. By combining these pollinators into an Integrated Crop Pollination strategy, the risk of poor pollination may be minimized.

    Pollen is moved by bees

    For pollination to occur, sufficient compatible blueberry pollen must be moved from the male part of flowers (anthers) to the female part (stigma) while the flowers are receptive. Bees are responsible for this movement of pollen, so blueberry pollination depends on having enough bees active in the field during bloom to deliver pollen. Each flower must be visited once by a bumble bee or most native bees, or three times by honey bees to get enough pollen so that berries will grow to maximum size. There can be 10 million flowers per acre, so there is a lot of work for bees to do!

    The pollen produced by blueberry flowers is relatively heavy and doesn’t waft on the wind. It is held inside the flower by salt shaker-like structures called anthers until bees visit. They may release the pollen by jiggling the flower with their legs, as is the case for honey bees. Bumble bees and some other native bees are better adapted to release the pollen using a vibration behavior known as “buzz pollination”. When the bees shake the anthers the pollen collects on their bodies. As the bees move from flower to flower, pollen grains are transferred to the stigma. Flowers are receptive to pollen immediately on opening, and their chance of turning into a berry declines after 3 days, with flowers unlikely to turn in to fruit after 5-6 days. Once compatible pollen is deposited on the stigma, the pollen germinates and fertilizes the ovules which produce the tiny seeds. Fertilized seeds release hormones that stimulate berry growth, leading to larger berries.

    Figure 1. Comparison of blueberries picked on the same day in July from clusters that had either been bagged to exclude pollinators (left) or were uncovered during bloom (right) allowing bees to visit. Both sets had the same number of blooms during flowering in May. Credit: Rufus Isaacs

    Things to know before planting

    Northern highbush blueberry bushes can produce berries even when there is no or limited pollen deposition by bees. This means that some proportion of the flowers can turn into berries, even if there are poor pollination conditions or low bee activity during bloom. However, these berries will be small, slow to ripen, may drop off early, and most would not be considered marketable (Figure 1, left). To reach maximum potential yield, it is important that the flowers are visited by bees during bloom to transfer sufficient pollen to the stigma while the flower is still viable so that fertilization can occur, leading to seed set, berry expansion, and larger berries (Figure 1, right). If designing a blueberry field of any appreciable size (over a few acres), make sure there will be space for a beekeeper to drop hives on pallets near the field.

    Table 1. Variation among highbush blueberry cultivars in the need for a pollinizing cultivar to provide cross-compatible pollen during bloom.

    Dependence on a pollinizing cultivar

    Cultivar

    Low: no pollinizer needed

    Duke, Draper, Bluejay, Nelson, and Rubel

    Intermediate: pollinizer beneficial

    Bluecrop, Legacy, Jersey, Liberty, Elliott, and Aurora

    High: pollinizer needed

    Brigitta, Spartan, Chippewa, Polaris, and Toro

    For some cultivars it is not sufficient just to get high rates of pollen transfer from bees, because the type of pollen can be important. Some cultivars benefit from the transfer of cross-compatible pollen, meaning that the field should be designed to have a combination of cultivars that bloom around the same time and that are compatible. For cultivars dependent on having cross-pollination for full yields, this can provide a 10-20% increase in yield from the improved fruit set and berry size. Table 1 provides a guide to cultivars and their level of dependence on this cross pollination for full yields. However, many popular northern highbush blueberry cultivars are self-fruitful, meaning they can be fertilized by pollen from the same cultivar (High group in the table), and this is one reason why solid blocks of some cultivars can be highly productive. Other cultivars are intermediate, meaning that a benefit can be gained by interplanting with another cultivar, but for many commercial settings growers might consider the increased complications in management outweigh the benefits.

    In a third group, cross-pollination is needed, and this is achieved by bees moving pollen between cultivars as they fly from row to row. In this situation, planting fields with alternating blocks of co-blooming and compatible cultivars ensures cross-pollination. While alternate rows of two compatible cultivars would be the best for pollination, it would also cause difficulties with harvesting and spraying. Alternating blocks of up to eight rows allows pollen exchange and is easier to manage. Alternating blocks of larger sizes will result in too few exchanges between cultivars that need cross pollination. Before purchasing blueberry plants, check with your nursery to determine the need for planting fields with alternating cultivars.

    Using honey bees for blueberry pollination

    Wait until bloom has started to bring in bees. Flowers of blueberries are generally less attractive to honey bees than other flowers due to the relatively low nectar reward. Because of this, it is best to bring in bees once the crop has started to bloom so that bees forage more on blueberries than other flowers (Figure 2). If brought in too early, bees may learn to forage elsewhere reducing their focus on your crop fields. Move bees into blueberry fields after 5% bloom but before 25% percent of full bloom. Placement near to the blueberry field can also help to keep them focused on the crop. Still, some cultivars (notably Jersey) have low attractiveness, and bees may still fly over this cultivar to reach another. 

    Figure 2. A honey bee drinking nectar from a blueberry flower. This is the workhorse of blueberry pollination, and to achieve high yields the fields must be stocked with sufficient numbers of healthy colonies during bloom to ensure there are enough bees for sufficient transfer of pollen between flowers. Credit: Jason Gibbs

    Renting healthy colonies. If you are renting honey bee hives, you should expect to receive healthy and vigorous bees. A healthy colony contains around 30,000 worker honey bees and will have six frames of brood. Having weak hives will affect how much pollination the fields receive, so it is worth taking time to ensure you have strong hives. If you suspect weak colonies, talk to your beekeeper about getting additional hives or replacing them. One strong hive of 30,000 bees will provide better pollination than two 15,000 bee hives because there will be more worker bees that fly to visit flowers. One way for growers to ensure they receive strong colonies is to establish a pollination agreement that lays out the grower’s expectations. This can include the strength of the colonies and how quickly the colonies will be taken out of the field after bloom. Example pollination contracts are available online.

    Honey bee stocking densities. There have been many changes in blueberry production and in bees over the past few decades, and yet many people still refer to bee stocking recommendations published in 1992. We consider those to be suitable for fields with lower bloom density, such as in a field affected by frost or when it is still establishing, and these can also be used in small fields surrounded by natural lands that will have higher populations of wild bees. However, if fields have a high flower density as some of the newer cultivars and intensive production systems provide or if field sizes are large without wild habitat nearby, then these recommendations are too low. The last few decades have also seen the loss of feral honey bee colonies due to the parasitic Varrroa mite, so those colonies are no longer contributing to blueberry pollination. All of these factors can make fruit production more dependent than ever on managed bees, so it is important to stock fields with sufficient bees to supply enough visits to flowers while they are most viable (i.e. in the first three days after opening). A final point to make here is that if the weather is hot during bloom and flowers open quickly, this increases the chance that they will not get visited before they lose viability. Higher stocking densities can counteract this potential limiting factor.

    Table 2. Recommended stocking density of honey bees for highbush blueberry pollination. Cultivars have varying rates of need for honey bees, and within each group we show a range of hives per acre to stock at, ranging from low rates for use in young, frost-damaged, or small fields to high rates for use in mature, healthy, or large fields. Adapted from Pritts & Hancock, 1992.

     

    Cultivar

    Honey bee hives/acre

    Low rate

    High rate

    Rubel, Rancocas

    0.5

    1

    Weymouth, Bluetta, Blueray

    1

    2

    Bluecrop

    1.5

    3

    Elliot, Coville, Berkeley, Stanley

    2

    4

    Jersey, Earliblue

    2.5

    5

    Research and experience in blueberries has shown variation across northern highbush cultivars in their needs for bee pollination (Table 2), due to the relative attractiveness of different cultivars and their degree of self-compatibility. The table below shows a range of stocking densities from the lower rates recommended two decades ago to the updated double rate that we consider the required stocking density for fully productive modern fields. This shows 5 hives per acre for Jersey and Earliblue, but some growers are using up to 8 colonies per acre to ensure good pollination if spring weather is cool and there are only a few good days for honey bee activity. These higher stocking densities can also be considered a form of pollination insurance, to make sure that whatever the spring brings there will be the best chance of good pollination.

    A rule of thumb is that you'll need 4 to 8 honey bees per bush in the warmest part of the day during bloom to get blueberries pollinated. Also, if you see flowers turning brown and discolored on the bush, pollination was not sufficient – in well-pollinated fields the corollas fall off when they are still bright white. Check your fields this season, and if needed you can try to get additional hives from a beekeeper, or plan on increased stocking next spring.

    Hive placement. If possible, place the colonies in sheltered locations with the entrances facing east or south. This will encourage earlier activity as the hive warms in the morning sun. Hives should be spread out around the farm to maximize floral visitation, with a maximum of 300 yards between hives. Placement in an open area slightly away from the edge of the fields also reduces the risk of pesticide drifting onto colonies of the colonies being disturbed by a tractor.

    Using bumble bee colonies

    Bumble bees are very efficient at pollinating blueberry, with activity at lower temperatures than honey bees, faster visits to flowers, and higher rates of pollen transfer per flower visit. A single visit of a bumble bee to a blueberry flower can deposit sufficient pollen to get full pollination, whereas three visits are needed by honey bees.

    Figure 3. Bumble bees are efficient pollinators of blueberry, so they should be encouraged on the farm. They can also be purchased from commercial suppliers and their colony boxes placed near fields to provide crop pollination. Credit: Jason Gibbs

    The common Eastern bumble bee, Bombus impatiens (Figure 3), has been reared for use as a crop pollinator. These insects are available commercially and can be shipped directly to the farm in eastern US states and Canada. Koppert is one supplier based in Michigan that provides the bees in Quads, each containing four colonies housed within a weather-proof box. Our evaluations with this species in commercial Jersey fields found they provided comparable yield and fruit set to honey bees, when tested in small fields at the recommended stocking density of 3 colonies per acre. Growers may also purchase bumble bees to integrate with honey bees, thereby diversifying pollination sources. This approach should help ensure movement of pollen between flowers during conditions that are unsuitable for honey bees. Rearing bumble bees takes time so orders should be made 14-16 weeks in advance to guarantee delivery. Place Quads through the farm and well away from honey bee hives. A door on the box of the Quads can be used to collect the bees and move them before spraying.      

    Wild bee pollinators

    While ants, butterflies, and hover flies will visit blueberry flowers to gather nectar, bees are the most effective at moving pollen. Over 150 wild bee species have been found in Michigan blueberry fields, and about ten of these were sufficiently abundant during bloom and carried enough pollen to be considered valuable crop pollinators. These bees do best in farms with flowers for them to visit outside the crop bloom period and in farms where there are some undisturbed areas for nesting (Figure 4), and farms can be managed to enhance their abundance.

    Wild bees fall into several major categories, including: bumble bees, miner bees, sweat bees, mason bees, and carpenter bees. Bumble bees and some sweat bees form social colonies later in the summer, but in spring during blueberry bloom these are bees are in a solitary phase. Miner bees, mason bees and carpenter bees are solitary: each nest is built by a single female. Miner bees are abundant during the spring, and some species, such as Andrena carolina, are specialists on blueberries.

    Figure 4. Many wild bee species require flowers to visit when the crop is not in bloom and areas of undistubed soil for nesting. Top, a miner bee gathering pollen from an early spring flower; bottom, a sweat bee searching for a place to nest in the soil. Credit: Jason Gibbs

    Wild bees nest in different areas in and around blueberry fields. Miner bees and most sweat bees make underground nests. A female bee tunnels into the soil, preparing brood cells for her young on side branches from the main tunnel. Pollen and nectar is collected and shaped into a ball placed in a each cell. A single egg is laid on each pollen ball which provides food for the developing larva. These bees need untilled soil and have been seen nesting underneath blueberry bushes in the weed-free strip. Thick layers of mulch can prevent ground nesting bees from digging tunnels. Some bees also nest in the undisturbed soil in nearby woods. Bumble bees also need undisturbed soil to nest in abandoned rodent burrows or grass tussocks, but they will also use old mattresses, compost piles, and other protected sites with small entrances. Finally some wild bees, such as carpenter bees, and some sweat bees, and mason bees prefer to nest in twigs, dead wood, or pre-existing cavities. Brambles, logs, and tree stumps in adjacent habitat and fence rows can be useful nesting sites for these bees.

    In small blueberry fields surrounded by natural habitat, wild bees can provide the majority of pollination. However, as blueberry farm size and intensity increase, the high abundance of flowers and the small amount of natural area results in too few native bees for full pollination, and so growers rent honey bees. Still, by creating bee habitat that includes a mix of plants that bloom before and after blueberries growers can help support native bees as part of an Integrated Crop Pollination strategy. For more on native plants to support pollinators in the Great Lakes region, visit www.nativeplants.msu.edu. Every little bit of habitat will help, so consider this a long-term process of building bee habitat back into the farm landscape. The Natural Resources Conservation Service can provide cost share for growers interested in establishing pollinator habitat in their farms. See your local NRCS office for details of programs that can support this.

    Pest management during pollination

    Most insecticides have some level of toxicity to bees, and so there are restrictions on their use during bloom. Not spraying while honey bees are in the field is the most effective way to avoid any risk of poisoning, so monitoring for pest problems carefully before and during bloom can help minimize the need for pest control at this time of the season. However, insect outbreaks do occur and this time of the season is an important one for control of mummyberry, so if a pesticide application is necessary during bloom the compounds that are least toxic to bees should be used, with careful observation of the pollinator restrictions on the label. Two insecticides that can be applied during bloom for control of moth larvae in blueberry are products containing Bacillus thuringensis (Bt) (e.g. Dipel, Javelin), and the insect growth regulators Intrepid and Confirm.

    The U.S. Environmental Protection Agency (EPA) has developed new pesticide labeling guidelines for certain insecticides, which limit their use where honey bees are present. This information is gradually being added to the labels of some insecticides, including neonicotinoids and the new product Exirel. Since these pesticides have never been labeled for use during bloom in blueberry, this is not a significant change but it provides more information. The EPA’s infographic can be downloaded from: www.epa.gov/pesticides/ecosystem/pollinator/bee-label-info-graphic.pdf.

    If spraying during the bloom period, one of the most important things growers can do to minimize effects on bees is to apply when the bees are not foraging. Late evening is the best time to apply sprays during bloom, because the compounds have time to be absorbed and for the residues to dry before bees are active the following morning. Dust formulations must be avoided because particles can be picked up easily by the bees’ hairy bodies.

    Recent research has also found that certain fungicides have effects on bees, harming their gut microbes and making them more susceptible to parasite infections. This can in turn result in reduced colony health and increased mortality. Follow the same basic principles of spraying only when necessary and when bees are not foraging to reduce the potential for harming bees during bloom.

    More information and a list of pesticides with their toxicity to bees is available from a recently-updated extension bulletin from Oregon State University at http://bit.ly/OSU_ReduceBeePoisoning. This document also contains a list of insecticides and fungicides ranked by their relative risk to bees, and plenty of other good information on how to prevent bee poisoning. Another important aspect of reducing the chance for pesticide incidents during bloom is to have good communication with your beekeeper. This should start in the winter with a discussion about how many hives you plan to rent, where they should be put, and when they should be delivered and removed. A recent MSU article on how to minimize pesticide exposure to bees is posted here: http://msue.anr.msu.edu/news/minimizing_pesticide_exposure_to_bees_in_fruit_crops

    Summary

    Pollination is an essential component of growing blueberries. To attain high levels of fruit set with large evenly-ripening berries requires bees to deposit enough pollen on stigmas during bloom. This can be done by honey bees, other managed bees, and wild bees. As with pest management, reliance on one strategy may not be the most sustainable approach, so diversifying pollination sources can spread risk to ensure consistent pollination and profitable yields every year. Whichever bees are visiting flowers during bloom, ensuring the health and safety of these insects is an important part of maintaining good pollination. Follow label restrictions and practice good pollinator stewardship so they can provide the all-important transfer of pollen that will lead to large berries and high yields. 

    This article was first published by Michigan State University Extension. Development of the article was supported by MSU’s AgBioResearch, Project GREEEN, and the USDA-SCRI Integrated
    Crop Pollination project (
    www.projecticp.org)
     

  2. Managing Small Hive Beetles

    What you can do to prevent or limit their damage

    Author: Jon Zawislak, University of Arkansas, Division of Agriculture

    Update: To view and print a PDF of Small Hive Beetle Management in Mississippi by Audrey Sheridan, Harry Fulton, and Jon Zawislak,  Click Here

    The small hive beetle Aethina tumida (SHB) is an invasive pest of bee hives, originally from sub-Saharan Africa.  These beetles inhabit almost all honey bee colonies in their native range, but they do little damage there and are rarely considered a serious hive pest. 

    It is unknown how this pest found its way into the U.S., but was first discovered to be damaging honey bee colonies in Florida in the late 1990s.  It has since spread to more than 30 states, being particularly prevalent in the southeast.  The beetles have likely been transported with package bees and by migratory beekeepers, but the adult beetles are strong fliers and are capable of traveling several miles at a time on their own. 

    In the United States these beetles are usually considered to be a secondary or opportunistic pest, only causing excessive damage after bee colonies have already become stressed or weakened by other factors.  Infestations of beetles can put significant stress on bee colonies, which can be compounded by the stress of varroa mites and other conditions.  If large populations of beetles are allowed to build up, even strong colonies can be overwhelmed in a short time. 

    Honey bee colonies appear able to contend with fairly large populations of adult beetles with little effect.  However, high beetle populations are able to lay enormous numbers of eggs.  These eggs develop quickly and result in rapid destruction of unprotected combs in a short time.  There is no established threshold number for small hive beetles, as their ability to devastate a bee colony is related to many factors of colony strength and overall health.  By maintaining strong bee colonies, and keeping adult beetle populations low, beekeepers can suppress the beetles’ reproductive potential.


    Fig. 1.  SHB adults are often observed in the hive with their head and antennae tucked down beneath the thorax.  They are oblong in shape, around 6 mm long, and with variable coloration that ranges from tan to reddish-brown, dark brown or black.

    Fig. 2.  SHB larvae will grow to about 1/2" in length.  They possess 3 pairs of well-developed legs, and have rows of short spines projecting from their bodies.

    Description

    Adult SHB are 5-7 mm (1/4”) in length, oblong or oval in shape, tan to reddish brown, dark brown or black in color, and covered in fine hairs, but their size and appearance can be highly variable within a population.  The adults are usually observed in the hive with their heads tucked down beneath the thorax, so that antennae and legs are often not apparent (Fig. 1).  The larvae are elongated, cream-colored to slightly golden grubs, growing to 10-12 mm (1/2”).  They may be mistaken for young larvae of the greater wax moth (Galleria mellonella).  The two types of larvae can be differentiated by their appearance.  Beetle larvae (Fig. 2) have three pairs of well-developed legs near the anterior end, while wax moth larvae have three pairs of legs near the anterior and four pairs of less-developed prolegs toward the posterior.  SHB larvae also have numerous dorsal spines, which wax moth larvae are lacking.  Both pests can be found simultaneously in the same hive, however.

    Honey bees are not able to efficiently remove adult beetles from the hive, and their hard shells resist stinging.  Rather, the bees are observed to pursue adult beetles across the combs.  Beetles will seek cracks and crevices in which to escape from the bees, who in turn will imprison the beetles in these cracks, preventing them from escaping.  The beetles have developed the ability to stimulate the mouth parts of worker bees with their antennae, similar to drones begging for food, and are able to trick their guards into feeding them.  This behavior allows the beetles to survive in confinement for extended periods. Opening hives for inspections may free the beetles from their confinement. 

    Sometimes the SHB population becomes too large for the worker bees to protect against, and the beetle population can increase rapidly.  This may happen due to weakening colony health or declining bee population, or due to beekeeper action.  When swarming occurs, the number of bees available to patrol the interior of the hive is reduced, which may allow the beetle population to surge.  When colonies are split, or nucs are created, the number of bees in the new colonies may be insufficient to protect against the beetle population.  Mating nucs used in queen rearing may be particularly susceptible to SHB.  Over-supering hives provides the beetles with excessive space in which to move and hide and provides additional oviposition sites, while increasing the area that the worker bees must patrol. 

    The use of grease patties for tracheal mite control, or the addition of protein supplement patties for spring build-up, may increase SHB infestations.  Both adult and larval beetles are attracted to these patties as a food source.  If patties are found to be infested with larvae, they should be removed immediately, and disposed of by wrapping them in several layers of plastic bags to prevent SHB from escaping.

    The adult female beetles will lay egg masses in cracks and crevices around the hive, or directly on pollen and brood combs.  Beetles may puncture the capping or wall of a brood cell and deposit eggs inside of it.  A single female beetle can produce over 1000 eggs in her lifetime.  Beetle eggs are similar in shape to those of honey bees, but approximately 2/3 the size.  Eggs generally hatch in 2-4 days, and the larvae immediately begin to feed on pollen, honey, and bee brood.  In 7-10 days, beetles complete their larval development and will exit the hive to pupate in the soil.  The majority of larvae remain within about 180 cm (6’) of the hive they exit, but can crawl much longer distances if needed.  Larvae will burrow up to 10 cm (4”) into the soil, where they remain 3-6 weeks to complete pupation.  Within 1-2 days of emerging from the soil, adult beetles will seek out a host bee colony, which they locate by odors (Fig. 3).

    The adults are strong fliers, and can disperse to other beehives easily.  Beetles are also thought to travel with honey bee swarms.  Individual beetles can live up to 6 months or more, and several overlapping generations of beetles can mature within in a colony in a single season.  Beetle reproduction ceases during the winter, when adult beetles are able to overwinter within the bee cluster.

    Fig. 3.  Life Cycle of the Small Hive Beetle.

    Damage

    Economic damage from SHB occurs when the bee population is insufficient to protect the honey combs from the scavenging beetle larvae.  When adult beetles first invade a colony, they may go unnoticed until their populations increase through reproduction or immigration.  Both adult and larval beetles will prey upon honey bee eggs and brood.

    When large numbers of beetle eggs hatch in weak colonies, the combs of honey can become “wormy” and take on a glistening, slimy appearance (Fig. 4).  Unlike wax moths, these beetle larvae do not necessarily damage the combs themselves, and do not produce extensive webbing.  Ruined honey can be washed from the combs, which may then be frozen for 24 hours to kill any beetles or eggs on them, and placed back onto a strong hive to be cleaned and repaired by the bees. 

    When large numbers of adult beetles defecate in the honey, they introduce yeasts, causing the honey to ferment and run out of the cells.  In this case, the queen bee may cease laying, and the entire colony may abscond. Weak colonies are particularly vulnerable to attack, but even strong colonies can be overwhelmed by large populations of beetles.  Nucleus colonies used for queen production or colony splits can be especially vulnerable to beetle attacks.

    Beetles can create sudden problems if bee escapes are used prior to harvesting, and supers of honey are left virtually undefended by bees.  If honey is removed from the hive, but not immediately extracted, beetles can invade the honey house and quickly ruin a large portion of a honey harvest.  Wet cappings from recently extracted honey are also extremely attractive and vulnerable to beetle infestation.  Honey contaminated by small hive beetles will be rejected by bees, is entirely unfit for human consumption, and should never be bottled or mixed with other honey for packing.


    Fig. 4.   Honeycombs infested with SHB larvae take on a glistening or "slimey" appearance.  Honey contaminated by beetle larvae is unfit for consumption by either bees or humans.

    Detection

    Beetles are easily detected by visual inspection of colonies.  When a hive is opened, adult beetles may be observed running across the underside of the outer cover, on either side of the inner cover, and on the top bars of frames.  Also, beetles may be seen running across the surfaces of combs (Fig. 5).  To detect beetles in the top hive body, open the hive and place the outer cover on the ground in a sunny spot, and place the top hive body into the cover (Fig. 6).  Conduct normal colony inspection activities on the rest of the hive.  If present in the top super, adult beetles will retreat from the sunlight, and after about 10 minutes you may lift the hive body and look for beetles in the cover.  Beetles in the lower hive body will similarly retreat to the bottom board as the colony is disturbed.

    Strips of corrugated cardboard, with the paper removed from one side, or pieces of corrugated plastic (obtained as scraps from a sign shop) can be placed on the bottom board at the rear of the hive.  Adult beetles, fleeing from bees, may seek shelter in the small spaces of the corrugations, and can be easily seen.  Bees may chew up and remove cardboard strips left in a hive for extended periods.

    Varroa sticky boards are usually ineffective in detecting small hive beetles.  Adult beetles prefer dark conditions, and will migrate toward the tops of hives that have screen bottoms, and may be more easily detected by placing corrugated strips on the top bars of the upper super or above the inner cover

    Small hive beetle larvae are often found clustered together in corners of a hive or on frames.  This behavior also differentiates them from wax moth larvae, which are found scattered throughout a hive.  Older beetle larvae orient toward light sources, and in the honey house, a single fluorescent light near the floor may attract beetle larvae, which exit the hives when seeking a place to pupate.  These larvae can be swept up and drowned in soapy water.

    Surfaces of combs that appear slimy, or fermented honey bubbling from the combs, are positive signs of beetle activity.  Fermented honey has an odor described as decaying oranges.

    If you suspect the presence of hive beetles, you may contact your state apiary inspector to arrange a visit, or you may bring a specimen in alcohol to your local Cooperative Extension office for positive identification.


    Fig. 5.  Adult beetles may be seen running across the combs, often pursued by honey bees.

    Fig. 6.  To detect SHB in the top super of a hive, place it on the hive lid in a sunny spot for abotu 10 minutes.  The bright light will drive the beetles down to the bottom.  If present, adult beetles should be visible on the lid when the super is lifted.

    Control

    Prevention is the most effective tactic of small hive beetle control.  Chemical controls are available, but are of limited use.  Good beekeeping management practices in the bee yard and in the honey house are sufficient to contain hive beetle problems in most cases.  A combination of cultural and mechanical controls will usually help to maintain beetle infestations within a manageable range. 

    Keep bee colonies healthy and strong.  Reduce stresses from diseases, mite parasitism, and other factors.  Maintain and propagate bee stocks with hygienic traits that are better able to detect and remove pests and diseased brood.  Eliminate, requeen, or strengthen weak colonies.

    Use caution when combining colonies or exchanging combs and hive bodies, because beetles and their eggs can be introduced into other colonies, which can be overwhelmed.  Making splits from heavily infested hives can cause a serious outbreak if insufficient numbers of bees remain to protect the hive.  Avoid over-supering hives, which increases the area that the bees must patrol.

    Maintain a clean apiary and honey house to reduce attraction to beetles.  Avoid tossing burr comb onto the ground around hives, which may attract pests.  Adult beetles tend to prefer shady locations.  If possible, place hives where they receive direct sunlight at least part of the day.  Keep hives and frames in good condition.  Warped, cracked and rotten hive bodies provide beetles with many places to hide, and make them more difficult to detect by bees or beekeepers.  When debris is left to accumulate on a bottom board, beetle larvae can complete pupation inside the hive.  Regular cleaning or use of screen bottom boards can prevent this build-up of debris.

    Honey that is removed from a colony should be extracted within 1-2 days.  Wax cappings are an attractive food for beetles, and should be processed quickly or stored in sealed containers.  Honey supers can be removed from weak colonies to lessen the territory of combs that the bees must patrol.  If not ready for extraction, these supers can be placed on strong colonies, in a manner similar to protecting them from wax moth infestations.  However, if small hive beetles or their eggs are present on the combs, the addition of these beetles can be sufficient to cause the strong colony to collapse.  Honey supers can be frozen at -12°C (10°F) for 24 hours to kill all stages of beetles before transferring supers to a strong colony.  Store empty supers under conditions of good air circulation and less than 50% humidity.

    Pollen traps should not be left on heavily infested hives for extended periods.  The unprotected pollen can serve as a substantial protein source for beetles, as well as a protected breeding site.

    Utilize mechanical traps in the hive to reduce the number of adult beetles that can produce eggs, while also reducing the need for pesticides.

    Mechanical Traps for eliminating Small Hive Beetles


    Numerous mechanical trap designs are available for use in the hive to control the adult SHB population.  Most traps kill beetles by drowning them in vegetable oil or mineral oil.  The traps have small openings that allow beetles to enter, but restrict the larger honey bees.  Some traps utilize a fermenting bait to attract the beetles into the trap, but beetles will enter non-baited traps to escape from the bees.  By maintaining a manageable adult beetle population in the hive, beekeepers can often prevent a major infestation of beetle larvae, which cause the the most destruction.

    The West Trap is placed on the bottom board, and requires a wooden shim to maintain proper space beneath the frames. It contains a shallow pool of oil, and is covered by a slatted screen that excludes bees. Adult beetles enter the trap from above, to escape from bees, and fall into the oil and drown.  Hives must be kept extremely level for these traps to be effective. These traps preclude the use of screen bottom boards for ventilation. 

    The Hood Trap attaches to a standard bee hive frame. It has a compartment filled with apple cider vinegar as an attractant, and compartments filled with mineral oil, which drown the beetles as they enter.  A potential drawback of this design is the empty space around the trap, which bees will often fill with drone comb, increasing a problem with varroa if left unattended. This area of drone comb, however, can be regularly removed and disposed of when about 50% of the drone cells are capped, which can effectively trap and remove a portion of reproducing varroa mites before they can emerge.

    The Freeman Beetle Trap is similar to the West Trap in function. It replaces the bottom board with a 3 mm (1/8”) screen mesh, as used for varroa control. An oil-filled tray is inserted into a compartment below the screen. Adult beetles enter the trap to escape from bees, and fall into the oil and drown.  Wandering beetle larvae may also fall into the trap as they attempt to exit the hive to pupate.  These traps can passively eliminate some varroa mites as well. Hives must be kept level for these traps to work.

    A variety of beetle traps, such as AJ’s Beetle Eater and Beetle Jail Jr., consist of shallow oil-filled troughs with slotted lids. These traps are suspended between frames of brood or honey. Adult beetles enter the traps to hide from bees, and are drowned in the oil.  These types of traps are inexpensive and easy to use, but may need to be emptied and refilled regularly.  Over time the bees may tend to propolize over some of the openings.  Some manufacturers suggests placing a small sheet of vinyl across the top of the trap to prevent propolizing, but this may provide the beetles with sufficient cover without entering the trap.  Similar in design and function, Cutt’s Beetle Blasters are disposable, and can be discarded when full of beetles.

    Beetlejail traps are designed to prevent hive beetles from invading a bee hive, by trapping them as they seek to enter, and drowning them in oil.

    Sonny-Mel traps are homemade, consisting of a small plastic sandwich box, with 3mm (1/8”) holes.  The bottom of the trap contains a shallow layer or layer of mineral oil, and a smaller container (usually a small plastic jar lid or bottle cap) of liquid bait.  To make a bait, combine 1 cup water, 1/2 cup apple cider vinegar, 1/4 cup sugar, and the peel of 1 ripe banana (chopped in small pieces); allow to ferment for 1-2 days.  These traps are placed on the top bars of the upper super, and require the addition of a wooden frame to provide space for the trap.

    This summary is provided as a convenience for the reader. The mention of any brand name or commercial product does not constitute or imply any endorsement, nor discrimination against similar products not mentioned.

    Soil Treatment

    The pupal stage is a vulnerable time in the beetle life cycle.  Slightly moist, loose, sandy soil is optimal for their development.  Locating colonies on hard clay or rocky soil, rather than light sandy soil, can reduce the number of beetle larvae that successfully pupate.  If numerous larvae are discovered in the hive, the soil around the colony can be treated with a permethrin drench to prevent the larvae from pupating, killing them in the soil.    Use with caution, as permethrin is highly toxic to bees!

    Prepare the site by removing fresh water sources and feeding stations.  Mow vegetation around the hives to be treated, to allow the solution to directly contact the soil.  Mix 5 ml (1 teaspoon) GardStar® 40% EC into 1 gallon of water (enough to treat 6 hives).  To avoid contaminating the bee hive surface with pesticide drift, do not use a sprayer.  Apply the solution using a sprinkler can.  Thoroughly drench the area in front of the hive (and beneath it, if screen bottom boards are used), wetting an area 18-24 inches around the hive, ensuring that wandering beetle larvae will contact treated soil.

    Application should be made late in the evening when few bees are flying.  Do not contact any surface of the bee hive or landing board with insecticide.  USDA testing indicates that permethrin binds to the soil and remains active for 30-90 days, depending on soil type, pH, and moisture content.  Reapply as needed. 

    Permethrin is corrosive and can cause irreversible eye damage.  Avoid contact with eyes, and wear proper eye protection during application.  Read and follow all label instructions for the legal and appropriate use of any pesticide.

    Studies have indicated that soil-dwelling entomopathogenic nematodes have potential to provide some control of pupating SHB.  Some species of these nematodes are commercially available from biological suppliers for use in the soil under and around bee hives.  It is not yet evident whether these nematodes are effective in all soil types, or if they can persist through drought or overwintering conditions in all areas, however, they may be useful as part of an overall integrated pest management plan.

    Because of insufficient scientific evidence on the efficacy of this control method, specific recommendations for the use of nematodes cannot be made at this time.

    Chemical Treatment in the Hive

    The chemical coumaphos (sold as Checkmite+ for varroa control) is the only pesticide registered for in-hive treatment of small hive beetles.  Consult your local Cooperative Extension office or Department of Agriculture for specific recommendations in your state.

    • Use 1 strip of Checkmite+ per hive.
    • Treatments should not be applied while surplus honey is being collected.
    • Do not place honey supers on a hive until 14 days after Checkmite+ strip has been removed, or treat hives after honey has been harvested.
    • Prepare a 4x4” piece of corrugated cardboard by removing the paper surface from one side, and cover the smooth side with duct tape or shipping tape to prevent the bees from tearing up or removing it.
    • Cut a single strip of Checkmite+ in half and staple both pieces to the corrugated side of the cardboard.
    • Chemical resistant gloves must be worn while handling strips – do not use leather bee gloves when handling this product!
    • Insert the cardboard square, strip side down, onto the center of the bottom board, or above the inner cover if screen bottom board is used.
    • Beetles will seek shelter in the corrugations and contact the strip.  Bees should not be able contact the pesticide.
    • Leave treatment strips in place for a minimum of 42 days, but no more than 45 days.
    • Dispose of strips according to label directions. 
    • Do not treat the same colony with coumaphos more than 2 times in one year. 

    These instructions are a presented as a general guideline.  Users are responsible for reading and following all label instructions for the legal and appropriate use of any pesticide. 

     

    Selected References

    • Cabanillas, H. E. & P. J. Elzen.  2006.  Infectivity of entomopathogenic nematodes (Steinernematidae and Heterorhabditidae) against the small hive beetle Aethina tumida (Coleoptera: Nitidulidae).  Journal of Apicultural Research 45: 49-50.
    • Ellis, J.D., C.W.W. Pirk, H.R. Hepburn, G. Kastberger & P.J. Elzen.  2002.  Small hive beetles survive in honeybee prisons by behavioral mimicry.  Naturwissenschaften 89: 326-328.
    • Ellis, J.D., S. Spiewok, K.S. Delaplane, S. Buchholz, P. Neumann, & W.L. Tedders.  2010.  Susceptibility of Aethina tumida (Coleoptera: Nitidulidae) larvae and pupae to entomopathogenic nematodes.  Journal of Economic Entomology 103: 1-9.
    • Hood, W.M.  2004.  The small hive beetle, Aethina tumida: a review.  Bee World 85: 51-59.
    • Sanford, M.T.  2003.  Small Hive Beetle.  University of Florida IFAS Extension publication ENY-133. 
    • Skinner, J.A.  2002.  The Small Hive Beetle: a New Pest of Honey Bees.  University of Tennessee Agricultural Extension Service publication SP 594.
    • Torto, B., R.T. Arbogast, D. Van Engelsdorp, S.D. Willms, D. Purcell, D. Boucias, J.H. Tumlinson & P.E. Teal.  2007.  Trapping of Aethina tumida Murray (Coleoptera: Nitidulidae) from Apis mellifera L. (Hymenoptera: Apidae) colonies with an in-hive baited trap.  Environmental Entomology 36:1018-1024.

     

    Image Credits

    • Fig 1.   (left) Division of Plant Industry Archive, Florida Department of Agriculture and Consumer Services, bugwood.org; (right) Natasha Wright, Florida Department of Agriculture and Consumer Services, bugwood.org.
    • Fig 2.   James D. Ellis, University of Florida, bugwood.org.
    • Fig 3.   Jon Zawislak, University of Arkansas Division of Agriculture, Cooperative Extension Service, www.uaex.edu.
    • Fig 4.   James D. Ellis, University of Florida, bugwood.org.
    • Fig 5.   James D. Ellis, University of Florida, bugwood.org.
    • Fig 6.   Chris Bryan.

    Download a printable
    fact sheet  from the
    University of Arkansas
    Division of Agriculture

     

     

  3. USDA-ARS Bee Labs
     

    The USDA-ARS sponsors five bee research labs at

    • Baton Rouge, Louisiana
    • Beltsville, Maryland
    • Logan, Utah
    • Tucsan, Arizona.
    • Weslaco, Texas

    Honey Bee Breeding, Genetics and Physiology Research Unit

    Baton Rouge, Louisiana bee lab

    Mission:
    The mission of the Honey Bee Breeding, Genetics and Physiology Research Unit is directly related to improving honey bee stock and honey bee management. This broad mission includes components related to problems caused by varroa mites, tracheal mites and Africanized honey bees. The devastating problems caused by varroa mites and the serious problems caused by tracheal mites are targeted as the most critical. Scientists are engaged in breeding and testing honey bees for resistance to mites, evaluating mite-bee interactions to better describe breeding criteria, and evaluate stock production processes to explore and solve stock problems caused by mites.


    Bee Research Laboratory in Beltsville

    Beltsville, Maryland bee lab

    Mission:
    The mission of the Bee Research Laboratory in Beltsville is to conduct research on the biology and control of honey bee parasites, diseases, and pests to ensure an adequate supply of bees for pollination and honey production. Using biological, molecular, chemical and non-chemical approaches, scientists are developing new, cost-effective strategies for controlling parasitic mites like Varroa destructor, bacterial diseases like American foulbrood, and emergent pests like the small hive beetle. Additional research focuses on virus transmission, and the impact of pests and pathogens on longevity and colony survival. Bee Research Laboratory staff also provides authoritative diagnosis of bee diseases and pests for Federal and State regulatory agencies and beekeepers on a worldwide basis.


    Pollinating Insects - Biology, Management and Systematics Research Unit

    Logan, Utah bee lab

    Mission:
    The mission of the Pollinating Insect-Biology, Management, Systematics Research is the development of non-Apis bees, for example the alfalfa leafcutting bee and the blue orchard bee, as crop pollinators. Research emphasis areas include the development and improvement of management systems for bee populations, biological studies of bees, plant-pollination systems, and bee biosystematics. Cross-pollinated crops not effectively pollinated by honey bees have been targeted for improved pollination management, and the candidacy of selected pollinator species continues to be evaluated. Current research on established species, like the alfalfa leafcutting bee and the blue orchard bee, is directed toward developing control programs for pests and diseases, improving management that will result in better bee health and demonstrating pollination efficacy and increased producer profitability on "new" crops.


    Carl Hayden Bee Research Center

    Tucsan, Arizona bee lab

    Mission:
    The mission of the Carl Hayden Bee Research Center (CHBRC) is to conduct research to optimize the health of honey bee colonies, through improved nutrition and control of Varroa mites, in order to maximize production of honey bee pollinated crops.


     

    Honey Bee Research Unit (HBRU) at Kika de la Garza Subtropical Agricultural Research Center

    Mission: The mission of the Honey Bee Research Unit (HBRU) is to develop technology for managing honey bees in the presence of africanized honey bees, parasitic mites, stress and diseases. This lab was shut down in 2012. Many of the researchers migrated to the Carl Hayden Bee Lab in Tucson Arizona.

  4. All Bugs Good and Bad Webinar Series Draws to a Close

    The 2014 All Bugs Good and Bad Webinar Series concludes November 7, with the presentation of a webinar on pollinators by University of Tennessee Professor of Entomology, Dr. John Skinner. This webinar will be moderated by Sallie Lee, an Urban Regional Extension Agent with the Alabama Cooperative Extension System.

    Skinner's webinar is titled “Where Have All the Honeybees Gone? Hope for the Future." He is a repeat presenter in the webinar series. Skinner presented the first webinar of 2014 discussing pollinators, “If Flowers are Restaurants to Bees, What are Bees to Flowers?

    Alabama Extension Entomologist Dr. Kathy Flanders said the webinar series-opener, presented by Skinner, had the highest recorded attendance of any webinar during the series. His first webinar presentation had more than 250 attendees. 

    “I am pleased at the interest in the All Bugs Food and Bad Webinar series. We have had excellent speakers, and great viewer participation,” Flanders said. “To date, more than 700 people attended the live webinars, and nearly 6,000 watched the recording. We are looking forward to Dr. Skinner’s webinar, because there is so much misinformation about honeybee health. Dr. Skinner will provide unbiased, science-based information on this topic.”

    Bees and other pollinators are responsible for the pollination of more than two-thirds of the world’s food crops. More than flowers and back yard gardens are in need of bees. Cotton and alfalfa are two crops that have major impacts on the agricultural industry and need bees for pollination.

    The All Bugs Good and Bad Webinar Series has featured many insects that affect both homeowners and producers. Termites, ticks, mosquitoes, spiders and fire ants are among insects featured in the webinar series.

    More information about the series can be found on the All Bugs Good and Bad Webinar page. Links to archived webinars can be found on that page as well.

    The webinars were sponsored by eXtension and the Alabama Cooperative Extension System.  They are coordinated by the Imported Fire Ant eXtension Community of Practice, Urban IPM, Bee Health, Invasive Species, Gardens, Lawns and Landscapes, & Disasters

    Photo courtesy of David Cappaert, Michigan State University, bugwood.org.

  5. Has research been done on honey bees comparing 5.4 mm comb cell size with 4.9 mm? I have heard that small cell (4.9 mm) beekeeping can control varroa mites.

    Below is a listing of research into European honey bees on small cell combs. Three of the articles (1, 2, and 5) deal with small cell and varroa mites. All three conclude that small cell does not help the bees deal with varroa mites, or otherwise reduce varroa mite numbers. Article #3 shows that small cell combs do not reduce tracheal mites. Study #4 is unrelated to small cell's effect on parasitic mites and shows that smaller combs do result in smaller bees, when measuring specific morphological characters.

    references

    1. Berry, J. A., Owens, W. B., and Delaplane, K. S. (2010). Small-cell comb foundation does not impede Varroa mite population growth in honey bee colonies. Apidologie 41: 40-44.
    2. Ellis, A. M., Hayes, G. W., and Ellis, J. D. (2009). The efficacy of small cell foundation as a varroa mite (Varroa destructor) control. Experimental and Applied Acarology 47(4): 311-316.
    3. McMullan, J. B., Brown, M. J. F. (2006). Brood-cell size does not influence the susceptibility of honey bees (Apis mellifera) to infestation by tracheal mites (Acarapis woodi). Experimental and Applied Acarology 39: 273-280.
    4. McMullan, J. B., Brown, M. J. F. (2006). The influence of small-cell brood combs on the morphometry of honeybees (Apis mellifera). Apidologie 37: 665-672.
    5. Taylor, M. A., Goodwin, R. M., McBrydie, H. M., and Cox, H. M. (2008). The effect of honey bee worker brood cell size on Varroa destructor infestation and reproduction. Journal of Apicultural Research 47(4): 239-242.
  6. Frequently Asked Questions
    Two "expert" bee researchers ponder a quandary: "well, what do you think?" Credit: Zach Huang



     

          Beekeepers are almost by definition curious individuals. The nature of beekeeping, as with any environmental relationship, is complex. Even some of the most experienced beekeepers are confounded by the mysteries of a bee hive. That is what makes honey bee research a rewarding and never-ending journey.
          Below is a list of commonly asked questions and links to the best answer at the time it was asked. As more information becomes available, perceptions shift, and may render a formerly correct answer invalid. The following list is only a starting point and one should always seek a second opinion on any difficult or important subject. Local knowledge is especially important as geographical variables cannot be resolved in this universal forum. If your question is not listed below, consider using the Ask an Expert function.

     

  7. Honey Bee Lab and Organization Links
    Male Melissodes bees apparently sleeping in a sunflower. Credit: Zach Huang

          Many government agencies, private interest groups, and universities in the US and around the world work to better understand and protect honey bees and other pollinators. Many of these groups offer diagnostic or other services in honey bee health, while others feature informative resources for beekeepers, growers, gardeners, and other stakeholders.
          Below is a selection of websites that offer compelling and trustworthy information or services in the areas of honey bee and pollinator health. 

  8. Honey Bee Viruses, the Deadly Varroa Mite Associates

    If your bees have Varroa, your bees have viruses. 

    Authors: Philip A. Moore, Michael E. Wilson, and John A. Skinner
    Department of Entomology and Plant Pathology, the University of Tennessee, Knoxville TN
    Date: August 21, 2014

    Introduction

    Varroa mites (Varroa spp.) are a ubiquitous parasite of honey bee (Apis spp.) colonies. They are common nearly everywhere honey bees are found, and every beekeeper should assume they have a Varroa infestation, if they are in a geographic area that has Varroa (Varroa mites are not established in Australia as of spring 2014). Varroa mites were first introduced to the western honey bee (Apis mellifera) about 70 years ago after bringing A. mellifera to the native range of the eastern honey bee (Apis cerana). Varroa mites (Varroa jacobsoni) in eastern honey bee colonies cause little damage. But after switching hosts and being dispersed across the world through natural and commercial transportation of honey bee colonies, Varroa has became a major western honey bee pest since the 1980’s. Varroa mites (Varroa destructor) are now the most serious pest of western honey bee colonies and one of the primary causes of honey bee decline (Dietemann et al. 2012). A western honey bee colony with Varroa, that is not treated to kill the pest, will likely die within one to three years (Korpela et al. 1993; Fries et al. 2006).

    Varroa Life History

    Varroa mites attack honey bee colonies as an external parasite of adult and developing bees, by feeding on hemolymph (fluid of the circulatory system similar to blood), spreading disease, and reducing their lifespan. Evidence suggests that Varroa and their vectored viruses affect the immune response of honey bees, making them more susceptible to disease agents (Yang and Cox-Foster 2005). For more information on this topic see: https://www.extension.org/pages/64997/lessons-learned-by-the-managed-pollinator-cap:-impacts-of-Varroa-parasitism-on-honey-bee-health#.U-T-bONdU7k. Mature female Varroa mites survive on immature and adult honey bees (worker, drone, and rarely queen), are reddish brown, and about the size of a pin head. Male mites are a smaller size and tan color, do not feed on bees, and are only found inside brood cells (Rosenkranz et al. 2010).

    Varroa have two life stages, phoretic and reproductive. The phoretic stage is when a mature Varroa mite is attached to an adult bee and survives on the bee’s hemolymph. During this stage the mite may change hosts often transmitting viruses by picking up the virus on one individual and injecting it to another during feeding. Phoretic mites may fall off the host, sometimes being bitten when bees groom each other, or it may die of old age. Mites found on the bottom board of the hive or that fall though a screen bottom board are called the “natural mite drop”. But these mites that fall off of bees represent a small portion of the total mite population because the reproductive mites are hidden under cell cappings.

    Image 1: Reproductive Varroa mite on a developing pupa (reddish oval) and two immature Varroa (opaque ovals). Credit: Abdullah Ibrahim (arrows added for emphasis)

    The reproductive life stage of Varroa begins when an adult female mite is ready to lay eggs and moves from an adult bee into the cell of a developing larval bee. After the brood cell is capped and the larva begins pupating, the mite begins to feed. After about three days from capping, the mite lays its eggs, one unfertilized egg (male) and four to six fertilized (female) eggs (Rosenkranz et al. 2010). After the eggs hatch, the female mites feed on the pupa, mate with the male mite and the surviving sexually mature female mites stay attached to the host bee when it emerges as an adult. It takes six to seven days for a female mite to mature from egg to adult and it can live two to three months in the summer and five to eight months in the fall. Only mature female mites can survive outside of a brood cell (the phoretic stage), and on average a mite will produce 1.2 viable mature female offspring per worker cell invaded (Schulz 1984; Fuchs & Langenbach 1989). However, since the development time is longer for drone brood, the average viable offspring for a mite in a drone cell increases to 2.2 per cell invaded (Schulz 1984; Fuchs & Langenbach 1989). For more on Varroa life history see: https://www.extension.org/pages/65450/Varroa-mite-reproductive-biology#.U-Jn-eNdU7k

    Viruses

    One of the serious problems caused by Varroa is the transmission of viruses to honey bees which cause deadly diseases. Viruses found in honey bees have been known to scientists for 50 years and were generally considered harmless until the 1980’s when Varroa became a widespread problem. Since then, nearly twenty honey bee viruses have been discovered and the majority of them have an association with Varroa mites, which act as a physical and or biological vector (Kevan et al. 2006). Therefore controlling Varroa populations in a hive will often control the associated viruses and finding symptoms of the viral diseases is indicative of a Varroa epidemic in the colony. Viruses are however, the least understood of honey bee diseases. Emerging information of honey bee viruses continue to alter our understanding of the role viruses play in honey bee colonies (Genersch and Aubert 2010).

    Viral Life History

    Viruses are microscopic organisms that consist of genetic material (RNA or DNA) contained in a protein coat. Viruses do not acquire their own nutrients or live independently, and can only multiply within living cells of a host. An individual virus unit is called a virus particle or virion and the abundance of these particles in a host is called the virus titer. A virus particle injects itself in to a host cell and uses the cells’ organelles to make copies of itself. This process will continue without obvious change to the cell, until the host cell becomes damaged or dies, releasing large amounts of infective virus particles. All forms of life are attacked by viruses and most are host specific.

    Honey Bee Viruses

    Viruses of the honey bee typically infect the larval or pupa stage, but the symptoms are often most obvious in adult bees. Many of these viruses are consumed in pollen or the jelly produced by nurse bees that are fed to developing bees. Many viruses are also transmitted by Varroa. Varroa, when feeding on the hemolymph transfer the viruses directly into the open circulatory system, which reaches every cell in the insect body.

    Honey bee viruses are not limited to honey bees. Honey bee viruses have been found in other non-Apis bee species, other colony inhabitants like small hive beetle, and in pollen and nectar (Andersen 1991; Bailey and Gibbs 1964; Genersch et al. 2006; Singh et al 2010). For more on honey bee pathogens found in native bees see: https://www.extension.org/pages/30998/wild-bee-status-and-evidence-for-pathogen-spillover-with-honey-bees#.U-UAJONdU7k. Transfer of honey bee viruses from infected colonies to non-infected individuals or colonies can occur during foraging on common flowers or through robbing of weak or collapsed colonies (Singh et al 2010). 

    Identification of a virus is difficult due to the small size of particles. Expensive and often uncommon laboratory equipment is required for accurate diagnosis. However, symptoms of some viral diseases are more visible, especially with overt infection. A lack of symptoms does not rule out the presence of a virus. Viruses can remain in a latent form within the host, acting as a reservoir of infection, complicating diagnosis and control, and only becoming an outbreak when conditions are right.

    Viral Prevalence in the United States

    The USDA-APHIS National Honey Bee Pests and Diseases Survey has taken samples from honey bee colonies in over 27 states since the year 2009. Data from these surveys and other data are complied into a database with the Bee Informed Partnership and used to determine baseline disease level, determine the absence of exotic honey bee pests that have not yet been found in America, and to gauge the overall health of U.S. honey bee colonies. Results of virus presence from the 2013 survey are below (Figure 1). Deformed wing virus (DWV) and Black queen cell virus (BQCV) were present in over 80% of sampled colonies. Other viruses were much less common, but still present in 10-20 percent of colonies sampled. Of the viruses tested for presence, only slow bee paralysis virus (SBPV) was not found in the U.S

    Figure 1: 2013 USDA-APHIS National Honey Bee Pests and Diseases Survey, Virus Prevalence Results (Virus abbreviations: BQCV=Black queen cell virus; DWV= Deformed wing virus; LSV2= Lake Sinai virus 2; ABPV= Acute bee paralysis virus; KBV= Kashmir bee virus; IAPV= Israel acute paralysis virus; CBPV= Chronic bee paralysis virus; SBPV= Slow bee paralysis virus)

    Sacbrood

    Sacbrood, a disease cause by a virus, was the first honey bee virus to be discovered in the early 20th century and now has a recognized widespread distribution. It is perhaps the most common honey bee viruses (Shen et al. 2005). This disease has been found in adult, queen, egg, and larval bees, in all forms of food, and in Varroa mites, suggesting a wide range of transmission routes. Although it is commonly found without serious outbreak, sacbrood is more likely to cause disease when the division of labor is less defined, in the early parts of the year before the nectar flow, or during prolong dearth (Bailey 1981). It often goes unnoticed since it usually infects only a small portion of brood, and adult bees will usually detect and remove infected larvae.

    Image 2: Sacbrood infected pupa. Credit: Michael E. Wilson

    The disease causes larvae to fail to shed their final skin prior to pupation, after the larva has spun its cocoon. Infected larvae remain on their back with their head towards the cell capping. Fluid accumulates in the body and the color will change from pearly white to pale yellow, with the head changing color first. Then, after the larva dies, it becomes dark brown with the head black (Image 2). Larvae that have ingested sufficient quantities of sacbrood in their food die after being sealed in their comb.

    Sacbrood multiplies in several body tissues of young larvae but these larvae appear normal until cell capping. Each larva that dies from sacbrood contains enough virus particles to infect every larva in 1000 colonies (Bailey 1981). But in most instances, diseased larvae are quickly removed in the early stages of the disease by nurse bees. The cell cappings are first punctured to detect the disease, which a good sign of infection for the beekeeper look for (Image 6). Then, young worker bees remove the diseased larvae from the colony. Adult bees, although not susceptible to infection, become a harbor as the virus collects in the bee’s hypopharyngeal glands, which are used to produce larval jelly (Bailey 1981). These infected adult bees, however, cease to eat pollen and soon stop tending larvae. They will become foragers more quickly in life than usual and tend to collect nectar instead of pollen (Bailey 1981).  Nectar that contains the virus becomes diluted in the colony when mixed with nectar from other foragers. Whereas pollen, is collected and compacted into the “pollen basket” and deposited intact into a cell. Dilute virus containing nectar is less likely to cause infection than when the virus is concentrated in a pollen pellet. Therefore use caution when transferring frames with pollen among colonies. Little is known of the other transmission routes: through Varroa mites, between workers, from bee feces or through transovarial transmission (from queen to egg). Sacbrood usually subsides in late spring when the honey flow begins, but if symptoms persist, requeening with hygienic stock is recommended (Frazier et al. 2011).

    Deformed Wing Virus (DWV)

    Deformed wing virus is common, widely distributed, and closely associated with Varroa mites. Both the virus titers and prevalence of the virus in colonies are directly linked to Varroa infestations (Bowens-Walker et al. 1999). In heavily Varroa infested colonies, nearly 100 percent of adult workers may be infected with DWV and have high virus titers even without showing symptoms (de Miranda et al. 2012). DWV is strongly associated with winter colony mortality (Highfield et al 2009; Genersch et al 2010). Control of DWV is usually achieved by treatment against Varroa,  After treatment a gradual decrease in virus titers occurs as infected bees are replaced by healthy ones (Martin et al 2010). DWV can be found in all castes and life stages of honey bees and will persist in adults without obvious symptoms. DWV is also transmitted through food, feces, from queen to egg, and from drone to queen (de Miranda et al. 2012).

    Image 3: Adult bees with deformed wings resulting from DWV. Credit: Katherine Aronstein

    Acute infections of DWV are typically linked to high Varroa infestation levels (Martin et al 2010). Covert infections (a detectable level of virus without damaging symptoms) can occur through transovarial transmission (Chen et al. 2004), and through larval food (Chen et al. 2006). Symptoms noted in acute infections include early death of pupae, deformed wings, shortened abdomen, and cuticle discoloration in adult bees, which die within 3 days causing the colony to eventually collapse. Not all mite infested pupae develop these symptoms, but all adult honey bees with symptoms develop from parasitized pupae. Bees infected as adults can have high virus titers but do not develop symptoms. DWV may also affect aggression (Fujiyuki et al. 2004) and learning behaviors of adult bees (Iqbal and Muller 2007). DWV appears to replicate in Varroa, making it a biological as well as physical vector. Infection of pupae may be dependent on DWV replication in Varroa prior to transmission. Winter colony mortality is strongly associated with DWV presence, irrespective of Varroa infestation. This suggests that Varroa infection should be reduced in a colony far in advance of producing overwintering bees, to ensure reduction in DWV titers. DWV is closely related to Kakugo Virus and Varroa destructor Virus 1, which together form the Deformed Wing Virus Complex (de Miranda et al. 2012).

    Black Queen Cell Virus (BQCV)

    Black queen cell virus is a widespread and common virus that persists as asymptomatic infections of worker bees and brood. Although generally understood as being asymptomatic in adult bees, Shutler et al. (2014) found BQCV to be associated with the symptom K-wing, where the wing pair is disjointed and more perpendicular to one another. Queen pupae with symptoms display a pale yellow sac-like skin similar to sacbrood. The pupae rapidly darken after death and turn the wall of the queen cell dark brown to black. Symptomatic drone pupae have also been observed. Unlike other viruses that are associated with Varroa, BQCV is strongly associated with Nosema apis and little evidence supports its co-occurrence with Varroa, although, BQCV has been isolated from Varroa (Ribière et al. 2008). Nosema disease affects a bee’s mid gut, increasing susceptibility of the alimentary tract to infection by BQCV. BQCV can be orally transmitted to adults only when Nosema has co-infected (Ribière et al. 2008). It can also be transmitted by injection to pupae. BQCV has a seasonal relationship similar to Nosema, with a strong peak in spring. Because of the seasonal occurrence with Nosema, queen rearing operations who produce queens in the spring are susceptible to BQCV (Ribière et al. 2008).

    Image 4: Dysentery on the front of a hive is a symptom but not indicative of Nosema disease. Credit: Michael E. Wilson

    Chronic Bee Paralysis Virus (CBPV)

    Chronic bee paralysis virus was one of the first honey bee viruses to be isolated. It is unique among honey bee viruses in that it has a distinct particle size and genome composition. It is also the only common honey bee virus to have both visual behavior and physiological modifications resulting from infection. Symptoms of the disease are observed in adult bees displaying one of two sets of symptoms called syndromes (Genersch & Aubert 2010). Type 1 symptoms include trembling motion of the wings and bodies of adult bees, who are unable to fly, and crawl along the ground or up plant stems, often clustering together. The bees may also have a bloated abdomen, causing dysentery and will die within a few days after displaying symptoms.

    Type 2 symptoms are greasy, hairless, black adult bees that can fly, but within a few days, become flightless, trembling, and soon die (Image 5). Both of these syndromes can occur within the same colony. Severely affected colonies, often the strongest in an apiary (Ribiere at al. 2010), quickly lose adult workers, causing collapse and often leaving few adult bees with the queen on unattended comb (Bailey & Ball 1991). These symptoms, however, are similar and often confused with other honey bee maladies including Nosema apis, colony collapse disorder (CCD), tracheal mites, chemical toxicity, and other viruses.

    Image 5: Bees with CBPV type 2 symptoms: greasy and hairless. Credit: The Food and Environment Research Agency (Fera), Crown Copyright

    Transmission of the virus primarily occurs through direct body contact, although oral transmission also occurs but is much less virulent. Direct body transmission happens when bees are either crowded or confined within the hive for a long period of time (due to poor weather or during long-distance transportation) or when too many colonies are foraging within a limited area, such as a monoculture of sunflower with high honey bee colony density (Genersch & Aubert 2010). In both instances, small cuts from broken hairs on an adult bee’s cuticle and direct contact with infected adult bees spreads the virus through their exposed pores; if this occurs rapidly and enough adult bees are infected, an outbreak with colony mortality will occur. Feces from infected bees within a colony can also spread the disease, and other transmission routes are still being investigated, including possible Varroa transmission. The virus is widespread and an outbreak can occur at any time of year. Spring and summer are the most common seasons for mortality from the virus, but it will persist in a colony year-round without displaying any overt symptoms (de Miranda et al. 2012).

    Two new viruses related to CBPV with no yet described symptoms are Lake Sinai virus 1 (LSV1) and Lake Sinai virus 2 (LSV2) (Runckel et al. 2011). New molecular tools have allowed researchers to identify the presence of these and other new viruses and their seasonality in test colonies. Little else is know of the Lake Sinai viruses, including its pathogenic or epidemiological significance. Other described honey bee viruses that were discovered before the advent of molecular techniques have no genomic data to reference; therefore newly discovered viruses may in fact be the already discovered viruses of the past such as Bee virus X and Y, Arkansas Bee Virus or Berkeley Bee Virus (Runckel et al. 2011).

    Acute Bee Paralysis Virus Complex

    Acute bee paralysis virus (ABPV), Kashmir bee virus (KBV), and Israel acute paralysis virus (IAPV) are a complex of associated viruses with similar transmission routes and affect similar life stages. These viruses are widespread at low titers and can quickly develop high titers due to extremely virulent pathology. Frequently associated with colony loss, this virus complex is especially deadly when colonies are heavily infested with Varroa mites. (Ball 1989; Genersch 2010, Genersh et al. 2010).  These viruses have not been shown to cause symptoms in larval life stages, but show quick mortality in pupae and adult bees.

    Acute Bee Paralysis Virus (ABPV)

    Acute bee paralysis virus was accidentally discovered when CBPV was first isolated. ABPV displays similar symptoms as CBPV however the acute adjective describes a bees’ more rapid mortality compared to CBPV. Unlike CBPV, ABPV virulence is directly related to Varroa infestation. APBV is transmitted in larval jelly from asymptomatic infected adult bees to developing larva or when vectored by Varroa mites to larvae and pupae. ABPV is common and typically cause covert infections (no obvious symptoms) when transmitted orally from adult to developing bee. It takes about one billion viral particles to cause death via ingestion, but when vectored by Varroa and directly injected into the developing bee’s hemolymph, only 100 virus particles will cause death (Genersch & Aubert 2010). When the virus is picked up by Varroa, the transmission rate to pupae is between 50 and 90 percent. The longer the feeding period of Varroa, the greater the transmission rate will become. (Genersch & Aubert 2010). Pupae infected with ABPV die before emerging, making the appearance of paralysis symptoms less obvious. The decline in emerging bees causes a colony to dwindle towards collapse. A colony infected with an ABPV epidemic will die within one season (Sumpter and Martin 2004). 

    Kashmir Bee Virus (KBV)

    Kashmir bee virus has widespread distribution and is considered the most virulent of honey bee viruses under laboratory condition (Allen and Ball 1996). When KBV is injected in to adult bee hemolymph, death occurs in just 3 days (de Miranda et al. 2012). KBV does not cause infection when fed to developing bees, but does persist in adult and developing bees without any obvious symptoms. When Varroa mites transmit the virus, it becomes deadly to all forms of the bee lifecycle but displays no clearly defined symptoms. Even with moderate levels of mite infestation, KBV, like ABPV, can kill colonies (Todd et al. 2007). Control of Varroa mites is necessary to prevent colony losses from KBV.

    Israeli Acute Paralysis Virus (IAPV)

    Symptoms of IAPV are similar to ABPV and CBPV including: shivering wings, darkened hairless abdomens and thoraxes, progressing into paralysis and death. IAPV is found in all life stages and castes of bees. IAPV and other viruses were found to be strongly associated with colony collapse disorder (CCD) in the United States, but no direct relationship between the viruses and CCD has yet been shown (Cox-Foster et al. 2007).  IAPV is extremely virulent at high titers, as when vectored by Varroa and is covert at low titers.

    Slow Bee Paralysis Virus

    In contrast to ABPV, which produces symptoms in a few days after infection, SBPV induces paralysis after 12 days, and only on the two fore (anterior) legs. SBPV persists as a covert infection and is transmitted by Varroa to adults and pupae. The disease will kill adult bees and eventually the entire colony (de Miranda et al. 2012). Prevalence of the virus is limited. It has not been found in the U.S., but has been found in England, Switzerland, Fiji and Western Samoa and only in Britain has SBPV been associated with colony deaths (Carreck et al. 2010).

    Summary

    Most pathogens invade the digestive system through oral ingestion of inoculated food. These pathogens infect the mid gut epithelial cells, which are constantly being replaced and are protected by membranes and filters which confine the pathogen to gut tissues. Parasites that infect gut tissue like Nosema apis and Nosema cerana can create lesions in the epithelium that allow a virus like BQCV to pass into the hemolymph and infect other cells in the body. In contrast the external parasite Varroa destructor feeds directly on bee hemolymph providing an opening in the cuticle for viruses to enter. Most virus infections rarely cause infection when ingested orally, but only a few virus particles are necessary to cause infection when injected directly into the hemolymph. Many viruses can be directly transmitted by Varroa mites, such as: DWV, those in the acute bee paralysis virus complex, and slow bee paralysis virus. Other viruses, like sacbrood, have been detected in Varroa mites but Varroa has not been shown to directly transmit the virus. Some viruses, like DWV, have been shown to directly multiply in Varroa mites, however in most cases we don’t know the exact relationship of Varroa mites to viruses or enough about how transmission occurs from mites to bees. Knowledge about the presence, role, and transmitting routes of these viruses in native bees, and other potential non-Varroa transmission routes is also lacking in detail, complicating recommendations for control. Research does show viruses clearly affect honey bee health and warrant attention from the beekeeper and researcher alike.

    Control

    Viruses persist in normal, healthy colonies, only to explode during times of stress. Many viruses are only damaging when in combination with another stressor like Varroa or Nosema. Active, integrated management of Varroa and other stressors is essential to minimizing virus titers. To learn more about reducing stressors with best management practices see: https://www.extension.org/mediawiki/files/8/8a/BMPs_with_CAP.pdf   

    Routinely inspect your colonies for possible disease. Have a thorough knowledge of symptoms and identify when colonies are slow to build up or have sporadic brood patterns, indicating brood has been pulled out and removed (Image 6). If you suspect you have a disease, take a sample and send it to be identified. For more information on submitting a sample for diagnosis see: http://www.ars.usda.gov/Main/docs.htm?docid=7472.

    Image 6: Punctured cell cappings that indicate adult bees have detected a brood disease (note DWV infected adult bee). Credit:  The Food and Environment Research Agency (Fera), Crown Copyright (Arrows added for emphasis)

    Other future avenues of control include breeding hygienic bee strains that detect brood diseases and remove infected individuals from colonies or breeding of resistance to Varroa infestation. Specific resistance to viruses are not yet considered in most breeding programs. There is evidence of specific viral resistance in honey bees, and there has been at least some attempt to breed resistance to IAPV. For more on this topic see: https://www.extension.org/pages/61384/an-update-on-bee-breeding-efforts-in-indiana:-breeding-for-resistance-to-israeli-acute-paralysis-vir#.U-UAX-NdU7k .

    Another promising research area for controlling honey bee viruses in the use of gene silencing called RNAi. The private bee research company Beeologics, as well as public and private university researchers are developing this method and a consumer product may be available in the near future as RNAi technology continues to become more efficient and inexpensive. For more on this topic see: https://www.extension.org/pages/70965/managed-pollinator-cap-update:-rnai-for-treating-honey-bee-diseases#.U-UAs-NdU7k

    References  

    1. Allen, M. and B.V. Ball. 1996. The incidence and world distribution of the honey bee viruses. Bee World 77: 141-162.
    2. Anderson DL (1991) Kashmir bee virus - a relatively harmless virus of honeybee colonies. Am. Bee J. 131: 767–770.
    3. Bailey, L. 1981. Honey bee pathology. Academic Press. London. 9-25.
    4. Bailey, L. and B. V. Ball. 1991. Honey bee pathology (2nd ed.). Academic Press. London
    5. Bailey L, Gibbs AJ (1964) Acute infection of bees with paralysis virus. J. Insect Pathol. 6: 395–407.
    6. Ball, B. V. 1989. Varroa jacobsoni as a virus vector. In Present Status of Varroatosis in Europe and Progress in the Varra Mite Control. Proc. Meeting, Undine, Italy, 1988. Cavalloro, E. (Ed.) EC-Experts Group, Luxembourg. pp. 241-244.
    7. Bowen-Walker, P. L., S. J. Martin, & A. Gunn. 1999. The Transmission of Deformed Wing Virus between Honeybees (Apis mellifera L.) by the Ectoparasitic Mite Varroa jacobsoni Oud. Journal of invertebrate pathology 73(1), 101-106.
    8. Carreck, N. L., D. V. Ball, & S. J. Martin. 2010. Honey bee colony collapse and changes in viral prevalence associated with Varroa destructor. J. Apic. Res. 49(1), 93-94.
    9. Chen, Y. P., J. S. Pettis, A. Collins, & M. F. Feldlaufer. 2006. Prevalence and transmission of honeybee viruses. Applied and environmental microbiology 72(1), 606-611.
    10. Chen, Y., J. S. Pettis, J. D Evans, M. Kramer, & M. F. Feldlaufer. 2004. Transmission of Kashmir bee virus by the ectoparasitic mite Varroa destructor. Apidologie 35(4), 441-448.
    11. Cox-Foster, D. L., S. Conlan, E. C. Holmes, G. Palacios, J. D. Evans, N. A. Moran, P. Quan, T. Briese, M. Hornig, D. M. Geiser, V. Martinson, D. vanEngelsdorp, A. L. Kalkstein, A. Drysdale, J. Hui, J. Zhai, L. Cui, S. K. Hutchinson, J. F. Simons, M. Egholm, , J. S. Pettis, W. I. Lipkin. 2007. A metagenomic survey of microbes in honey bee colony collapse disorder.  Science 318(5848), 283-287.
    12. Dietemann, V., J. Pflugfelder, D. Anderson, J. D. Charrière, N. Chejanovsky, B. Dainat, J. de Miranda, K. Delaplane, F. Diller, S. Fuch, P. Gallman, L. Gauthier, A. Imdorf, N. Koeniger, J. Kralj, W. Meikle, J. Pettis, P. Rosenkranz, D. Sammataro, D. Smith, O. Yañez, P. Neumann. 2012. Varroa destructor: research avenues towards sustainable control. Journal of Apicultural Research 51(1): 125-132
    13. Evans, J. D., & R. S. Schwarz. 2011. Bees brought to their knees: microbes affecting honey bee health. Trends in microbiology 19(12), 614-620.
    14. Francis, R. M., S. L. Nielsen, & p. Kryger. 2013. Varroa-virus interaction in collapsing honey bee colonies. PloS one 8(3).
    15. Fujiyuki, T., H. Takeuchi, M. Ono, S. Ohka, T. Sasaki, A. Nomoto, & T. Kubo, 2004. Novel insect picorna-like virus identified in the brains of aggressive worker honeybees. Journal of virology 78(3), 1093-1100.
    16. Fraxier, M., C. Dewey, & D. vanEngelsdorp. 2011. A field guide to honey bees and their maladies. Ag Communications and Marketing # AGRS-116. The Pennsylvania State University.
    17. Fries, I, A. Imdorf,P.  Rosenkranz. 2006. Survival of mite infested (Varroa destructor) honey bee (Apis mellifera) colonies in a Nordic climate. Apidologie 37: 564-570
    18. Fuchs, S. & K. Langenback. 1989. Multiple infestation of Apis mellifera L. brood cells and reproduction of in Varroa jacobsoni Oud. Apidologie, 20, 257–266.
    19. Genersch, E. 2010 Honey bee pathology: Current threats to honey bees and beekeeping. Appl. Microbiol. Biotechnol. 87, 87-97.
    20. Genersch, E., W. von der Ohe, H. Kaatz, A. Schroeder, C. Otten,R. Büchler ... & P. Rosenkranz. 2010. The German bee monitoring project: a long term study to understand periodically high winter losses of honey bee colonies. Apidologie 41(3), 332-352.
    21. Genersch, E., & M. Aubert. 2010. Emerging and re-emerging viruses of the honey bee (Apis mellifera L.). Veterinary research 41(6), 54.
    22. Genersch, E., C. Yue, I. Fries, & J. R. de Miranda. 2006. Detection of Deformed wing virus a honey bee viral pathogen, in bumble bees ( Bombus terrestris and Bombus pascuorum) with wing deformities.Journal of invertebrate pathology 91(1), 61-63.
    23. Gochnauer, T. A. 1978. Viruses. In Morse, R. A., & Nowogrodzki, R. (Eds.) Honey bee pests, predators, and diseases, (2nd ed). Cornell University Press.
    24. Highfield, A. C., A., El Nagar, L. C. Mackinde, M. L. N. Laure, M. J. Hall, S. J. Martin, & D. C. Schroeder. 2009. Deformed wing virus implicated in overwintering honeybee colony losses. Applied and environmental microbiology 75(22), 7212-7220.
    25. Iqbal, J., & U. Mueller. 2007. Virus infection causes specific learning deficits in honeybee foragers. Proceedings of the Royal Society B: Biological Sciences 274(1617), 1517-1521.
    26. Kevan, P. G., M. A. Hannan, N. Ostiguy, & E. Guzman-Novoa. 2006. A summary of the Varroa-virus disease complex in honey bees. Am. Bee J. 146 (8), 694-697.
    27. Korpela, S. A. Aarhus, I. Fries, H. Hansen. 1992. Varroa jacobsoni Oud. in cold climates: population growth, winter mortality and influence on the survival of honey bee colonies. Journal of Apicultural Research 31: 157-164.
    28. Martin, S. J.,  B. V. Ball, & N. L. Carreck. 2010. Prevalence and persistence of deformed wing virus (DWV) in untreated or acaricide-treated Varroa destructor infested honey bee (Apis mellifera) colonies. Journal of Apicultural Research 49(1), 72-79.
    29. de Miranda, J. R., B.Dainat,  B. Locke, G.Cordoni,  H. Berthoud, L. Gauthier,... & D. B.Stoltz. 2010. Genetic characterization of slow bee paralysis virus of the honeybee (Apis mellifera L.). Journal of General Virology 91(10), 2524-2530.
    30. de Miranda, J. R., L. Gauthier, M. Ribiere, and Y. P. Chen.  2012. Honey bee viruses and their effect on bee and colony health. In D. Sammataro & J. Yoder (Eds.) Honey bee colony health: challenges and sustainable solutions. CRC Press. Boca Raton. 71-102.
    31. Ribière, M., B. Ball, & M. Aubert. 2008. Natural history and geographical distribution of honey bee viruses. In M. Aubert (Ed.) Virology and the honey bee. European Communities, Luxembourg, 15-84.
    32. Ribière, M., V. Olivier, & P. Blanchard. 2010. Chronic bee paralysis: A disease and a virus like no other? Journal of invertebrate pathology 103, 120-131.
    33. Rosenkranz, P., P. Aumeier, & B. Ziegelmann. 2010. Biology and control of Varroa destructorJournal of invertebrate pathology 103, 96-119.
    34. Runckel, C., M. L. Flenniken, J. C. Engel, J. G. Ruby, D. Ganem, R. Andino & J. L. DeRisi. 2011. Temporal analysis of the honey bee microbiome reveals four novel viruses and seasonal prevalence of known viruses, Nosema, and CrithidiaPloS one 6(6).
    35. Schulz, A. 1984. Reproduktion und Populationsentwicklung der parasitischen Milbe Varroa jacobsoni Oud. in Abhänkgigkeit vom Brutzyklus ihres Wirtes Apis mellifera L. Apidologie 15, 401–420.
    36. Shen, M., L. Cui, N. Ostiguy, & D. Cox-Foster. 2005. Intricate transmission routes and interactions between picorna-like viruses (Kashmir bee virus and sacbrood virus) with the honeybee host and the parasitic Varroa mite. Journal of General Virology 86(8), 2281-2289.
    37. Shutler, D., Head, K., Burgher-MacLellan, K. L., Colwell, M. J., Levitt, A. L., Ostiguy, N., & Williams, G. R. (2014). Honey Bee Apis mellifera Parasites in the Absence of Nosema ceranae Fungi and Varroa destructor Mites. PloS one,9(6), e98599.
    38. Singh R, Levitt AL, Rajotte EG, Holmes EC, Ostiguy N, et al. (2010) RNA Viruses in Hymenopteran Pollinators: Evidence of Inter-Taxa Virus Transmission via Pollen and Potential Impact on Non-Apis Hymenopteran Species. PLoS ONE 5(12).
    39. Sumpter, D. J., & S. J. Martin 2004. The dynamics of virus epidemics in Varroa‐infested honey bee colonies. Journal of Animal Ecology73(1), 51-63.
    40. Todd, J. H. J. R. de Miranda, and B. V. Ball. 2007. Incidence and molecular characterization of viruses found in dying New Zealand honey bee (Apis mellifera) colonies infested with Varroa destructor. Apidologie 38: 354-367.
    41. Yang, X. and D.L. Cox-Foster. 2005. Impact of an ectoparasite on the immunity and pathology of an invertebrate: Evidence for host immunosuppression and viral amplification. Proceedings of the National Academy of Sciences of the United States of America 102 (21): 7470-7475.
    Thank you to Jay Evans (USDA-ARS) for review of this article
  9. Honey Bees Disease and Pest Resources

    Download a diagnostic manual for all honey bee ailments

    Many diseases, parasites, predators, and conditions affect honey bee colonies.

    In addition to pages on eXtension.org, the following resources can guide you in the identification and treatment of these issues.

    Diagnosis of Honey Bee Diseases; Shimanuki, H. and Knox, D. A.; USDA-ARS Agriculture Handbook Number 690; Download a .pdf of Diagnosis of Honey Bee Diseases


    Additional websites for honey bee health information:


    A family of varroa mites found at the bottom of a honey bee brood cell. Photo by Scott Bauer, USDA-ARS.

     

  10. Bee Health Contents
  11. Native Bees
    Metallic sweat bee (Augochlora pura). Photo by Philip Moore. Credit: Sam Droege

     

          Honey bees (Apis mellifera) are but one species among thousands of different bees within the superfamily Apoidea. Honey bees are unique in their societal life cycle and storage of large food reserves; most bees are solitary, nest individually, and do not store surplus food. Honey bees are not native to America and were imported from Europe early on during colonization. Native bees have evolved with the existing flora and some have established intricate relationships with particular flowers. Conserving populations of native bees is important because they are valuable pollinators of many plant species, often performing pollination more effectively than honey bees.
          Understanding some of the characteristics of native bees will help foster a positive environment for all bees. Below are a few articles that will help explain a bit about native bees.

  12. Dance Language of the Honey Bee

    Social behavior in bees has a number of advantages. One of the most important of these is the ability to quickly mobilize a large number of foragers to gather floral resources that may only be available for a short period of time. The ability to communicate location with such precision is one of the most interesting behaviors of a very interesting insect.

    The recruitment of foragers from a hive begins when a scout bee returns to the hive engorged with nectar from a newly found nectar source. She begins by spending 30-45 seconds regurgitating and distributing nectar to bees waiting in the hive. Once her generosity has garnered an audience, the dancing begins. There are 2 types of bee dances: the round dance and the tail-wagging or waggle dance, with a transitional form known as the sickle dance.

    In all cases the quality and quantity of the food source determines the liveliness of the dances. If the nectar source is of excellent quality, nearly all foragers will dance enthusiastically and at length each time they return from foraging. Food sources of lower quality will produce fewer, shorter, and less vigorous dances; recruiting fewer new foragers.

    The Round Dance

    Photo: Bill Tietjen, Bellarmine University

    The round dance is used for food sources 25-100 meters away from the hive or closer. After distributing some of her new-found nectar to waiting bees the scout will begin running in a small circle, switching direction every so often. After the dance ends food is again distributed at this or some other place on the comb and the dance may be repeated three or (rarely) more times.

    The round dance does not give directional information. Bees elicited into foraging after a round dance fly out of the hive in all directions searching for the food source they know must be there. Odor helps recruited bees find the new flowers in two ways. Bees watching the dance detect fragrance of the flower left on the dancing bee. Additionally, the scout bee leaves odor from its scent gland on the flower that helps guide the recruits.

    The Waggle Dance

    As the food source becomes more distant the round dance is replaced by the waggle dance. There is a gradual transition between the round and waggle dance, taking place through either a figure eight or sickle shaped pattern.

     

    Shown here is a dancing bee on a swarm. The marked bee has returned from a sugar water feeder. She is seen here being unloaded by a number of bees, and then begins to dance, which communicates the source of sugar water related to the current sun azimuth. This recording was produced at the University of California, Riverside by Kirk Visscher.


    The waggle dance includes information about the direction and energy required to fly to the goal. Energy expenditure (or distance) is indicated by the length of time it takes to make one circuit. For example a bee may dance 8-9 circuits in 15 seconds for a food source 200 meters away, 4-5 for a food source 1000 meters away, and 3 circuits in 15 seconds for a food source 2000 meters away.

    Photo: Bill Tietjen, Bellarmine University

     

     

     

     

     

    Direction of the food source is indicated by the direction the dancer faces during the straight portion of the dance when the bee is waggling. If she waggles while facing straight upward, than the food source may be found in the direction of the sun.

    Photo: Bill Tietjen, Bellarmine University

     

     

     

     

     

     

     

     

     

     

    If she waggles at an angle 60 degrees to the left of upward the food source may be found 60 degrees to the left of the sun.

    Photo: Bill Tietjen, Bellarmine University

     

     

     

     

     

     

     

     

     

     

     

    Similarly, if the dancer waggles 120 degrees to the right of upward, the food source may be found 210 degrees to the right of the sun. The dancer emits sounds during the waggle run that help the recruits determine direction in the darkness of the hive.

     

     


    Source: The information in this article was taken from "The Dance Language and Orientation of Bees" by Karl von Frisch

  13. Beekeeping Equipment

    A productive apiary with standard bee hive equipment on hive stands. Credit: The Food and Environment Research Agency (Fera), Crown Copyright
     

         The modern bee hive was invented by the Reverend L. L. Langstroth, patented in 1852, after his monumental discovery of "bee space". Bee space describes the phenomenon that if a space less than 1/4 inch is left the bees fill it with propolis (a glue like substance produced from tree sap) and, when a space larger than 3/8 inch is left the bees fill it with comb. The majority of bee hives used today are still based on Langstroth's design.
          Given the narrow range of tolerance with bee space, hive components must fit together tightly to limit excess or too little open space. Each manufacturer may produce bee hives slightly differently and combining components from different companies can cause problems. Careful research and experience with each company's components is important before investing in hive equipment. Below are articles to explain a few of the necessary hive equipment. 

  14. Collecting and Identifying Bees

    Collecting and identifying bees can be a fun and educational activity for all ages. It can also be an effective way to monitor ecological change and effects on bee diversity. Honey bees found in the United States (Apis mellifera) only represent one species out of over 3,500 US bee species.

     

     

     


    Bees, which are in the superfamily Apoidea, come in an amazing diversity of size, shape, color, and surface textures. Collecting bees brings a greater appreciation and understanding for this important facet of nature to both the collector and audience the collection is shared with.

     

     

    A collection of bees mounted in a Cornell insect drawer. Insect drawers offer protection and viewing through a glass cover. Insects in these drawers should be protected from dermestid beetles with and insecticide, in this case a red fumigant strip. Dermestid beetles find, then slowly eat and destroy unprotected insect collections.

     

    Resources available to help you develop a bee collection.


     

    Sam Droege, USGS Patuxent Wildlife Research Center, Beltsville, MD has several instructional videos on collecting bees. See his YouTube channel at: youtube.com/swdroege

     

    To identify bees to genus or species, special 'Keys' are used. Keys can be thought of as a flow chart of characters found on a bee that eventually lead you to the species name. Probably the most up to date key to identify bees in the USA, particularly east of Mississippi river, is an interactive key at:

    Help with identifying bees through photography in a public user website:

    Videos on collecting insects

    Characters used in Identifying Bees

     

    This bee has a character used in identification that we would describe as "Metallic race car green". To identify bees, you will need to look for specific characters that are used in keys. For examples, see: Characters used in Identifying Bees.

     

    Acknowledgments:

  15. Honey Bees and Beekeeping: Things are Buzzing

    Menu


    Part I

    1. Introduction

    • A Brief History
    • Building Supers and Frames
    • Preparing Food Supplements and Medications

    2. In the Beginning

    • Bee Biology and Equipment
    • Receiving and Installing Bees
    • Releasing Queens

    3. Things are Buzzing

    • Things are Buzzin
    • The Brood Nest
    • Our Growing Hives
    • Migrating our Hives

    4. A Mid-season Break

    • Requeening
    • Queen Rearing
    • Package Production, Beekeeping Associations, Books and Periodicals 

    Part II

    5. Diseases and Pests

    • Diseases and Pests
    • Chalbrood, Sacbrood, Moths, Tracheal Mites
    • Varroa Mites and Queenlessness

    6. It's Harvest Time

    • It's Harvest Time
    • Extracting Honey
    • Packaging and Selling Honey
    • Commercial Honey Processing

    7. Rounding Out the Year

    • Overwintering Hives
    • Overwintering and One Story Hives
    • Second Season Management
    • Fall Management

    Things are Buzzing

    • Things are Buzzin
    • The Brood Nest
    • Our Growing Hives
    • Migrating our Hives

    Things are Buzzing: Section 3.1: Things are buzzin

    Presented with permission of the University of Georgia Center for Continuing Education. To purchase the complete "Honey Bees and Beekeeping" television series on DVD or accompanying book, please call 1-800-359-4040.

    Things are Buzzing: Section 3.2: The brood nest

    Presented with permission of the University of Georgia Center for Continuing Education. To purchase the complete "Honey Bees and Beekeeping" television series on DVD or accompanying book, please call 1-800-359-4040.

    Things are Buzzing: Section 3.3: Our Growing Hives

    Presented with permission of the University of Georgia Center for Continuing Education. To purchase the complete "Honey Bees and Beekeeping" television series on DVD or accompanying book, please call 1-800-359-4040.

    Things are Buzzing: Section 3.4: Migrating our Hhives

    Presented with permission of the University of Georgia Center for Continuing Education. To purchase the complete "Honey Bees and Beekeeping" television series on DVD or accompanying book, please call 1-800-359-4040.

  16. Honey Bees and Beekeeping: A Year in the Life of an Apiary
    This online video walks you through one year of managing honey bee colonies.

    Menu


    Part I

    1. Introduction

    • A Brief History
    • Building Supers and Frames
    • Preparing Food Supplements and Medications

    2. In the Beginning

    • Bee Biology and Equipment
    • Receiving and Installing Bees
    • Releasing Queens

    3. Things are Buzzing

    • Things are Buzzin
    • The Brood Nest
    • Our Growing Hives
    • Migrating our Hives

    4. A Mid-season Break

    • Requeening
    • Queen Rearing
    • Package Production, Beekeeping Associations, Books and Periodicals 

    Part II

    5. Diseases and Pests

    • Diseases and Pests
    • Chalbrood, Sacbrood, Moths, Tracheal Mites
    • Varroa Mites and Quenlessness

    6. It's Harvest Time

    • It's Harvest Time
    • Extracting Honey
    • Packaging and Selling Honey
    • Commercial Honey Processing

    7. Rounding Out the Year

    • Overwintering Hives
    • Overwintering and One Story Hives
    • Second Season Management
    • Fall Management
     

    Introduction

    • A Brief History
    • Building Supers and Frames
    • Preparing Food Supplements and Medications

    Introduction: Section 1.1: A Brief History

    Presented with permission of the University of Georgia Center for Continuing Education. To purchase the complete "Honey Bees and Beekeeping" television series on DVD or accompanying book, please call 1-800-359-4040

    Introduction: Section 1.2: Building Supers and Frames

    Presented with permission of the University of Georgia Center for Continuing Education. To purchase the complete "Honey Bees and Beekeeping" television series on DVD or accompanying book, please call 1-800-359-4040

    Introduction: Section 1.3: Preparing Food Supplements and Medications

    Presented with permission of the University of Georgia Center for Continuing Education. To purchase the complete "Honey Bees and Beekeeping" television series on DVD or accompanying book, please call 1-800-359-4040

     

  17. Honey Bees and Beekeeping: In the Beginning

    Menu


    Part I

    1. Introduction

    • A Brief History
    • Building Supers and Frames
    • Preparing Food Supplements and Medications

    2. In the Beginning

    • Bee Biology and Equipment
    • Receiving and Installing Bees
    • Releasing Queens

    3. Things are Buzzing

    • Things are Buzzin
    • The Brood Nest
    • Our Growing Hives
    • Migrating our Hives

    4. A Mid-season Break

    • Requeening
    • Queen Rearing
    • Package Production, Beekeeping Associations, Books and Periodicals 

    Part II

    5. Diseases and Pests

    • Diseases and Pests
    • Chalbrood, Sacbrood, Moths, Tracheal Mites
    • Varroa Mites and Queenlessness

    6. It's Harvest Time

    • It's Harvest Time
    • Extracting Honey
    • Packaging and Selling Honey
    • Commercial Honey Processing

    7. Rounding Out the Year

    • Overwintering Hives
    • Overwintering and One Story Hives
    • Second Season Management
    • Fall Management

    In the Beginning

    • Bee Biology and Equipment
    • Receiving and Installing Bees
    • Releasing Queens

    In the Beginning: Section 2.1: Bee Biology and Equipment

    Presented with permission of the University of Georgia Center for Continuing Education. To purchase the complete "Honey Bees and Beekeeping" television series on DVD or accompanying book, please call 1-800-359-4040.

    In the Beginning: Section 2.2: Receiving and Installing Bees

    Presented with permission of the University of Georgia Center for Continuing Education. To purchase the complete "Honey Bees and Beekeeping" television series on DVD or accompanying book, please call 1-800-359-4040.

    In the Beginning: Section 2.3: Releasing Queens

    Presented with permission of the University of Georgia Center for Continuing Education. To purchase the complete "Honey Bees and Beekeeping" television series on DVD or accompanying book, please call 1-800-359-4040.

     

  18. Honey Bees and Beekeeping: Rounding Out the Year

    Menu


    Part I

    1. Introduction

    • A Brief History
    • Building Supers and Frames
    • Preparing Food Supplements and Medications

    2. In the Beginning

    • Receiving and Installing Bees
    • Medication
    • Releasing Queens

    3. Things are Buzzing

    • Things are Buzzin
    • The Brood Nest
    • Our Growing Hives
    • Migrating our Hives

    4. A Mid-season Break

    • Some Housekeeping
    • Packaged Bees and Queens
    • Bee Associations
    • Books and Periodicals

    Part II

    5. Diseases and Pests

    • Diseases and Pests
    • Chalbrood, Sacbrood, Moths, Tracheal Mites
    • Varroa Mites and Queenlessness

    6. It's Harvest Time

    • It's Harvest Time
    • Extracting Honey
    • Packaging and Selling Honey
    • Commercial Honey Processing

    7. Rounding Out the Year

    • Overwintering Hives
    • Overwintering and One Story Hives
    • Second Season Management
    • Fall Management

    Rounding Out the Year

    • Overwintering Hives
    • Overwintering and One Story Hives
    • Second Season Management
    • Fall Management

    Rounding Out the Year: Section 7.1: Overwintering Hives

    Presented with permission of the University of Georgia Center for Continuing Education. To purchase the complete "Honey Bees and Beekeeping" television series on DVD or accompanying book, please call 1-800-359-4040.

    Rounding Out the Year: Section 7.2: Overwintering and One Story Hives

    Presented with permission of the University of Georgia Center for Continuing Education. To purchase the complete "Honey Bees and Beekeeping" television series on DVD or accompanying book, please call 1-800-359-4040.

    Rounding Out the Year: Section 7.3: Second Season Management

    Presented with permission of the University of Georgia Center for Continuing Education. To purchase the complete "Honey Bees and Beekeeping" television series on DVD or accompanying book, please call 1-800-359-4040.

    Rounding Out the Year: Section 7.4: Fall Management

    Presented with permission of the University of Georgia Center for Continuing Education. To purchase the complete "Honey Bees and Beekeeping" television series on DVD or accompanying book, please call 1-800-359-4040.

  19. Honey Bees and Beekeeping: A Mid-season Break

    Menu


    Part I

    1. Introduction

    • A Brief History
    • Building Supers and Frames
    • Preparing Food Supplements and Medications

    2. In the Beginning

    • Receiving and Installing Bees
    • Medication
    • Releasing Queens

    3. Things are Buzzing

    • Things are Buzzin
    • The Brood Nest
    • Our Growing Hives
    • Migrating our Hives

    4. A Mid-season Break

    • Requeening
    • Queen Rearing
    • Package Production, Beekeeping Associations, Books and Periodicals 

    Part II

    5. Diseases and Pests

    • Diseases and Pests
    • Chalbrood, Sacbrood, Moths, Tracheal Mites
    • Varroa Mites and Queenlessness

    6. It's Harvest Time

    • It's Harvest Time
    • Extracting Honey
    • Packaging and Selling Honey
    • Commercial Honey Processing

    7. Rounding Out the Year

    • Overwintering Hives
    • Overwintering and One Story Hives
    • Second Season Management
    • Fall Management

    A Mid-season Break

    • Requeening
    • Queen Rearing
    • Package Production, Beekeeping Associations, Books and Periodicals 

    A Mid-season Break: Section 4.1: Requeening

    Presented with permission of the University of Georgia Center for Continuing Education. To purchase the complete "Honey Bees and Beekeeping" television series on DVD or accompanying book, please call 1-800-359-4040.

    A Mid-season Break: Section 4.2: Queen Rearing

    Presented with permission of the University of Georgia Center for Continuing Education. To purchase the complete "Honey Bees and Beekeeping" television series on DVD or accompanying book, please call 1-800-359-4040.

    A Mid-season Break: Section 4.3: Package Production, Beekeeping Associations, Books and Periodicals 

    Presented with permission of the University of Georgia Center for Continuing Education. To purchase the complete "Honey Bees and Beekeeping" television series on DVD or accompanying book, please call 1-800-359-4040.

  20. Honey Bees and Beekeeping: Diseases and Pests

    Menu


    Part I

    1. Introduction

    • A Brief History
    • Building Supers and Frames
    • Preparing Food Supplements and Medications

    2. In the Beginning

    • Receiving and Installing Bees
    • Medication
    • Releasing Queens

    3. Things are Buzzing

    • Things are Buzzin
    • The Brood Nest
    • Our Growing Hives
    • Migrating our Hives

    4. A Mid-season Break

    • Requeening
    • Queen Rearing
    • Package Production, Beekeeping Associations, Books and Periodicals 

    Part II

    5. Diseases and Pests

    • Diseases and Pests
    • Chalbrood, Sacbrood, Moths, Tracheal Mites
    • Varroa Mites and Queenlessness

    6. It's Harvest Time

    • It's Harvest Time
    • Extracting Honey
    • Packaging and Selling Honey
    • Commercial Honey Processing

    7. Rounding Out the Year

    • Overwintering Hives
    • Overwintering and One Story Hives
    • Second Season Management
    • Fall Management

    Diseases and Pests

    • Diseases and pests
    • Chalbrood, sacbrood, moths, tracheal mites
    • Varroa mites and quenlessness

    Diseases and Pests: Section 5.1: Diseases and Pests

    Presented with permission of the University of Georgia Center for Continuing Education. To purchase the complete "Honey Bees and Beekeeping" television series on DVD or accompanying book, please call 1-800-359-4040.

    Diseases and Pests: Section 5.2: Chalkbrood, Sacbrood, Moths, Tracheal Mites

    Presented with permission of the University of Georgia Center for Continuing Education. To purchase the complete "Honey Bees and Beekeeping" television series on DVD or accompanying book, please call 1-800-359-4040.

    Diseases and Pests: Section 5.3: Varroa Mites and Queenlessness

    Presented with permission of the University of Georgia Center for Continuing Education. To purchase the complete "Honey Bees and Beekeeping" television series on DVD or accompanying book, please call 1-800-359-4040.

  21. Honey Bees and Beekeeping: Its Harvest Time

    Menu


    Part I

    1. Introduction

    • A Brief History
    • Building Supers and Frames
    • Preparing Food Supplements and Medications

    2. In the Beginning

    • Receiving and Installing Bees
    • Medication
    • Releasing Queens

    3. Things are Buzzing

    • Things are Buzzin
    • The Brood Nest
    • Our Growing Hives
    • Migrating our Hives

    4. A Mid-season Break

    • Requeening
    • Queen Rearing
    • Package Production, Beekeeping Associations, Books and Periodicals 

    Part II

    5. Diseases and Pests

    • Diseases and Pests
    • Chalbrood, Sacbrood, Moths, Tracheal Mites
    • Varroa Mites and Queenlessness

    6. It's Harvest Time

    • It's Harvest Time
    • Extracting Honey
    • Packaging and Selling Honey
    • Commercial Honey Processing

    7. Rounding Out the Year

    • Overwintering Hives
    • Overwintering and One Story Hives
    • Second Season Management
    • Fall Management

    It's Harvest Time

    • It's Harvest Time
    • Extracting honey
    • Packaging and selling honey
    • Commercial honey processing

    It's Harvest Time: Section 6.1: It's Harvest Time

    Presented with permission of the University of Georgia Center for Continuing Education. To purchase the complete "Honey Bees and Beekeeping" television series on DVD or accompanying book, please call 1-800-359-4040.

    It's Harvest Time: Section 6.2: Extracting Honey

    Presented with permission of the University of Georgia Center for Continuing Education. To purchase the complete "Honey Bees and Beekeeping" television series on DVD or accompanying book, please call 1-800-359-4040.

    It's Harvest Time: Section 6.3: Packaging and Selling Honey

    Presented with permission of the University of Georgia Center for Continuing Education. To purchase the complete "Honey Bees and Beekeeping" television series on DVD or accompanying book, please call 1-800-359-4040.

    It's Harvest Time: Section 6.4: Commercial Honey Processing Presented with permission of the University of Georgia Center for Continuing Education. To purchase the complete "Honey Bees and Beekeeping" television series on DVD or accompanying book, please call 1-800-359-4040.

  22. Nosema apis and Nosema ceranae

    Nosema apis spores magnified 400X on a hemocytomer slide used for counting spores. Photo by Yuchuan Qin. Credit: Zach Huang

     

          Nosema apis and Nosema ceranae are single celled parasites of the honey bee midgut that can weaken individual bees and entire colonies, making them more susceptible to other pests and diseases, as well as affect digestion, metabolism, hormone production, queen egg laying, homing and learning. Millions of spores can be found within an individual bee and spores will persist on beekeeping equipment. Nosema apis has been well known to the beekeeping community for the last century, while Nosema ceranae, which was formerly primarily found in Apis ceranae, has recently become widespread in western honey bee colonies.

          Although knowledge is limited on N. ceranae much of the characteristics of N. apis is shared. Differentiation between the two pathogens is only possible through laboratory techniques, but the life history, transmission, and treatment is much the same. Below are articles that will describe those characteristics. 

  23. Varroa Mites
    Varroa mites as seen under a microscope. Credit: Zach Huang

          Varroa mites (Varroa destructor) are the foremost pest of western honey bee colonies. They inhabit nearly every honey bee colony in most of the world, transmit deadly viruses, shorten bee lifespan, limit productivity, and cause severe economic damage every year. Maintaining Varroa populations in the hive below the economic threshold is a primary activity of beekeepers and eradication of the pest is unlikely any time soon.

          Below are articles that detail the life cycle and biology of varroa, monitoring and treatment options, selecting for resistant stock, and impact of varroacides in the hive. 

  24. Webinars and Seminars
    A presentation at a honey bee conference. Credit:Zach Huang

          Researchers and other knowledgeable individuals commonly give presentations on their area of expertise, either at conferences or other smaller meetings. We try to record these seminars whenever possible to allow the widest audience for the presentation. Overtime some of the links to a seminar may be broken and unrecoverable, we will attempt to maintain an up-to-date list of our video content. Webinars and seminars that are recorded, archived online, and available for free can be found below. Other videos can be found on our YouTube channel.

  25. Advanced Field and Lab Techniques
    Artificial Insemination of a Honey Bee Queen. Credit: Courtesy The Food and Environment Research Agency (Fera), Crown Copyright

          For the intrepid beekeeper, especially those with access to a microscope or laboratory, many diagnostic techniques are available. Investing in a decent quality microscope, particularly when shared by a beekeeping club, is a worthwhile endeavor.
          Below are methods for a few advanced techniques that may be appropriate for experienced beekeepers, while others should only be attempted by those with significant training. If these techniques are of interest but beyond the skill set of a beekeeper, training classes are available from many universities and beekeeping organizations.