Know your honey bee colonies: non-destructive testing for varroa mites

Varroa mites (Varroa destructor) were accidentally introduced into the U.S. in 1987 and rapidly became a destructive pest of honeybees. Not only do varroa mites suck the blood (haemolymph) of the bees, they transmit disease through this feeding and generally weaken colonies (Rosenkranz et al. 2010).  Low infestations of varroa mites left without mitigation can develop into a serious problem for a hive. It is recommended you test your honey bees for varroa mites periodically throughout the season. Here in Minnesota, we test for varroa in spring (May), in late August or early September, and then after treatment has been on for the recommended time,…

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Oxalic Acid registered by EPA for use against Varroa mite on Honey bees

The varroa mite (Varroa destructor) has caused widespread devastation to honey bees through vampire-like feeding on larval and adult bees which decreases normal adult honey bee size, shortens their lifespan and can transfer viruses between bee hosts. (Rosenkrantz et al. 2010).                       Oxalic acid (CAS #144-62-7) has just been registered by the EPA for use on honey bee colonies here in the US. Oxalic acid has been legal to use on honeybees in Europe and Canada and is a naturally occurring chemical that can be found in a number of plants. It also occurs naturally…

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Varroa Mite Field Sample Processing Video

In our lab, we benefit from a diverse repertoire of individuals coming from varied backgrounds.  Working at a university includes the benefit of having motivated students with unique skills ready to use their talents.  Byron Mariani, a Sophomore Kinesiology Major, is one of these students who began working at the Bee Informed Partnership Lab at the beginning of the fall 2013 semester.  In addition to the help he provides in diagnosing colonies for Varroa, he has also proven himself invaluable with his video editing abilities.  With the help from our undergraduates, Anthony Nearman who provides a voice-over, and Kirsten Traynor who wrote the script, we…

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Spring in California 2014

The most opportune time for honey bee colonies in most areas of the U.S. is during spring build-up. The surplus of pollen and nectar that usually accompanies spring allows a growing colony to create a surplus of pollen and honey. It is also a time of year where the colony is trying to work through its kinks and get the colonies population dynamics under control as far as nurse bee to worker ratio. This ratio is crucial for hive ventilation and keeping moisture and bacteria from infiltrating the hive and causing problems. Some diseases that arise during this opportunistic time period are Chalkbrood, AFB, EFB…

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The Pygmy Shrew: A little mammal that is causing big problems in Canadian overwintering colonies

Typically when critter infestations come up into beekeeping conversation these common mammals come to mind: bears, skunks, mice, opossums and raccoons. Just like their size, pygmy shrews often fall under the radar. However, Fletcher Colpitts, Chief Apiary Inspector of New Brunswick, Canada, is working to make information about the pygmy shrew more available. He recently posted an info sheet about the pygmy shrew that every beekeeper should read: http://www.nbba.ca/wp-content/uploads/2014/03/shrew_screen.pdf The pygmy shrew is the smallest mammal native to North America. It can fit through a hole in a honey bee hive as little as 1 cm, and surprisingly only weighs an average of 3 grams.…

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Oxalic Acid Fogger Demostration

When it comes to Varroa control, beekeepers have always been concerned about mites' resistance to commercial treatments available on the market. It seems the arms race never ends, but changing up treatments throughout the year can help ensure that resistant mites don't get a foothold. There is a lot of interest in alternative mite control methods, and one that may be a useful addition to the beekeeper's toolbox is oxalic acid. Oxalic acid is an organic, naturally occurring compound which can be found in high concentrations in certain plants, notably spinach, rhubarb, and and the aptly named Oxalis. These plants use it as a deterrent…

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European Foulbrood (EFB)

EFB is often found when nectar flows are sporadic or there is an insufficient number of nurse bees to attend brood. How does EFB spread? European Foulbrood (Melissococcus plutonius) is transmitted when the bacteria become mixed with the bee bread, nectar or diluted honey, and then fed to young larvae. The bacteria then replicate in the larvae mid-gut, killing the larvae within 4-5 days. This causes the larvae to die before sealed in most cases. When the larvae dies it is left in a “stomach-ache” position making it look contorted or twisted in the cell. If the larvae are fed a small amount of the…

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BQCV (Black Queen Cell Virus)

So what is a virus? A virus is an infectious agent that parasitizes a host cell to replicate. Viruses can cause clinical symptoms, larvae death, or no symptoms at all. BQCV is caused by a virus in the family Dicistroviridae. BQCV is in the genus Cripavirus, which is different from other viruses like Acute Bee Paralysis Virus (ABPV), Israeli Acute Bee Paralysis (IAPV) and Kashmir Bee Virus (KBV) in the genus Aparavirus. Dicistroviruses infect many common insects like ants, bees, flies, leafhoppers, and aphids. The queen production industry is more likely to see this virus (hence its name) but it is still found in smaller…

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Chalkbrood

Chalkbrood (Ascosphaera apis) is typically observed during the spring but symptoms can be seen throughout the year. Chalkbrood contaminates larvae when the spores are mixed with brood food. The fungus will outcompete larvae for food and eventually turn the larvae into a “chalk-like” mummy. The color of chalkbrood ranges from white to grey then starts to turn black-this is when the fungus is producing fruiting bodies. This is the most infectious stage of chalkbrood. The black looking mummies are often what you see outside on the entrance board or in front of the hive. At this point these mummies can spread spores to other colonies…

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Sacbrood Virus (SBV)

SBV or Sacbrood Virus (Morator aetatulas) often appears during spring or colony buildup and causes larval death. The pupa fails to pupate and has a “shrunken head” appearance. When you see perforations in the sealed brood with the infected larvae inside, the perforation is usually choppy or jagged indicating a problem. If the SBV pupa is totally open, the capping has been completely removed by bees and the pupa is most likely greyish-yellow to brown and starting to dry out. When removed the pupa looks similar to a slipper or canoe. Infected adult bees will have decreased life spans. Symptoms: • Perforated sealed brood, pupa…

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