BCBC would like to thank
Dr. Zachary Huang, Associate Professor of Entomology, Michigan State University for allowing us to republish his honeybee photos and photo descriptions here. Please visit his site at Beetography.com
Special thanks also to
Dr. David Tarpy, Assistant Professor of Entomology at NCSU for allowing us to republish information on bee pests and treatments. You can visit his site here. |
Cause(s):
The parasitic mite, Varroa destructor
Symptoms:
--- Presence of adult mites on adult bees, brood, or hive debris
--- Adults with shortened abdomens, misshapen wings, and deformed legs
--- Dramatic decline in adult population and brood area, with spotty brood pattern
Treatment:
Spring (prior to honey flow)
--- If varroa levels are equal to or more than 2-3 mites per 100 adult bees
(sugar shake, ether roll, or alcohol wash) or 40-80 mites per 24 hours per
sticky board, treatment is warranted.
--- The use of volatile treatments, such as thymol or formic acid, are not
recommended since they can result in decreased brood area. Use the
appropriate dosage of Apistan® or Checkmite+® as long the mites have
not previously developed a resistance.
Late spring/summer (during/immediately following honey flow)
--- Never use any chemical treatments while honey supers are on hives.
--- Employ one or more means of prevention, such as screened bottom boards
or mite-tolerant stock.
Autumn (preparing for winter)
--- Sample frequently for mites, preferably once a month.
--- If varroa levels are equal to or more than 5-6 mites per 100 adult bees
(sugar shake, ether roll, or alcohol wash) or 100-150 mites per 24 hours
per sticky board, treatment is warranted.
--- Rotate treatments as often as possible to minimize the prolonged exposure
of any one chemical for the mites. This will help ensure that the mites do
not develop a resistance to the available treatments.
 Varroa mites (Varroa destructor) on a drone pupa that was removed from its cell.
 No, this is NOT a staged picture! Last October some colonies were dying and being robbed. On close inspection they were having very severe cases of PMS (parasitic mite syndrome). Very few brood cells were left and when I opened these cells, some had more than 20 mites per cell! This one had like 12 mites just near the top. Most of the time the larvae were already dead inside cells (this one looks alive). MSU apiary. Oct 14, 2002.
 Another larva with 5 varroa mites on one side, I am sure a few ran away... You can tell that the larva was dead by its abnormal coloration. MSU apiary. Oct 14, 2002.
 A varroa mite (Varroa destructor) and a "lesser mite" (as is called in China), Tropilaelaps clarae, side by side. Tropilaelaps jumped host from A. dorsata to A. mellifera in Asia. Hopefully it will never make its way to North America because in southern China it is sometimes more serious than varroa.
 A varroa mite (Varroa destructor) on the back of a worker bee. The bee on the bottom has her wings unexpanded -- a sign of varroa damage during her pupal stage.
 Varroa mites (Varroa destructor) floating in alcohol under a dissecting scope.
 Stages of varroa (Varroa destructor) mites. Younger ones on left, all white mites will die when a bee emerges out. The 2nd one from right would be able to live. Her cuticle will become redder after 2-3 more days of hardening. Beijing China. May 15, 2001.
 A varroa mite (Varroa destructor) on the back of a worker bee (the one in the center).
 Various stages of mites. The two rounder mites on the lower right are males. They never become red like the female and die soon after a worker or drone cell is open, perhaps due to debydration. May 15, 2001.
 The white defecation of a varroa mother mite on a worker pupae (near the tip of abdomen). This is usually a sign that the mite did not reproduce. Reproducing mites defecate on cell walls, not on the developing bee.
 All these six mites did not reproduce and all had defecated on the Apis cerana workers. This is also true in Apis mellifera: if a mite has defecated on the pupae, she would have no daughters. If she has daughter mites, she would be defecating on the wall.
 Varroa mites (Varroa destructor) on a drone pupa. Mites can survive in a lab setting like this for a few days
 Two happy families...based on the number of young mites here, there must be at least two mother mites in this cell (all mites were resident -- i.e. not staged). There are ten mites here (one male is out of focus near the far right side). You can click on the photo to get a more detailed view. Photo by Zachary Huang, Oct 16, 2003.
 Female mites of various stages, all from the same cell of the previous photo. The lowest one could be a male, which when not mature yet can difficult to tell from females. Mature males are more round, has a brownish to reddish tint and can move very quickly. None of the female nymph stages (when white) can move fast, if movable at all. Oct 16, 2003 |
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