:Craft: [Science] Common Bee Pests and Disease

I'm a big fan of visual media, so I always prefer to highlight video, where I can find it.

This time of year, after the packages and nucs are all installed, I begin to get questions from NewBees about what to watch for now.  Well, that's a big question with many answers.  It's pretty simple to show them in a week or two what eggs, larva, and even pupae look like.  It's a little harder to go into the details, without actually having ever seen them with your own eyes, what things like Varroa, Nosema, and Deformed Wing looks like etc.  It's a little more complicated since first year bees, on new frames, are in full build up mode and don't usually express many, or any, signs of the common sicknesses or pest problems.  It's usually late in the Fall or the next Spring before many of them start to show up.  Varroa is almost never a problem the first year, as there just isn't as much brood and as much comb to hide in yet.  The bees haven't been cooped up much so Nosema hasn't spread and settled in yet.

In this post I've gathered up some of the best resources I've come across for diagnosing and treating them the most common bee illnesses, disease and pests.


Dr. Jamie Ellis, University of Florida Extension, has compiled an EXCELLENT set of videos for diagnosing and treating common bee pests and illnesses.  The videos are very comprehensive.  The main site can be found here:  http://entnemdept.ifas.ufl.edu/afbee/resources/beekeepers.shtml

Small Hive Beetle: http://entnemdept.ifas.ufl.edu/afbee/resources/SmallHiveBeetle.shtml
Nosema: http://entnemdept.ifas.ufl.edu/afbee/resources/Nosema.shtml
Tracheal Mites: http://entnemdept.ifas.ufl.edu/afbee/resources/Trachaelmites.shtml
Varroa: http://entnemdept.ifas.ufl.edu/afbee/resources/varroavideo.shtml

Another video, which can be found in my post for NewBees is one by, by Dr. Keith DeLaplane of University of Georgia, which goes into some of these common bee health issues.  Chalkbrood is the main one I would have you see here.  http://www.youtube.com/watch?v=Lqq4W3WfKK0

A scary disease called American Foul Brood (AFB) is one to be aware of too.  You can spot the symptoms by checking capped brood cells.  AFB will kill and eat pupating (capped) bees.  This leads to a shrinking in of the tightly sealed cell.  The capping will collapse inwards, sinking or depressing it, and even cracking it open.  Inside you'll see a brown goopy mess, that was a developing bee.  If you push a stick or match inside, swirl it around a bit, then pull it back out, you'll see it's pretty sticky - "ropey" is the common description used.  Notice in this video that many of the cells are depressed inwards, many are cracked open, and the "ropey" or "stringy" nature of the destroyed pupae.  http://www.youtube.com/watch?v=Koi9aKBOFMA  Another demonstration of the "ropiness" of the pupae can be seen here: http://vimeo.com/5371036

There are some medications, Terramycin being the most common, and "best practices" for dealing with AFB.  My personal treatment is to get fresh new equipment (top, bottom, supers and frames).  Set the old equipment off to the side and put the fresh equipment in it's position.  Then shake the bees off their old frames, in front of the new equipment.  They head back inside and I treat them as if they were a new package of bees, just arrived.  Feed them and check for new eggs and larva.  I burn the old equipment and monitor the new for a return of the AFB.  This usually works, but on occasion I have had it return.  If AFB does return, I sadly destroy the whole colony - bees and all.

Another Foul Brood infection to watch for is European Foul Brood (AFB).  It's not nearly as dangerous as AFB, but does surface from time to time.  It usually clears itself up as the colony builds in strength and the weather dries out (as with so many of the other disease problems).  It can be spotted in the larva (before they are capped over, signaling their change to a pupae state).  The larva will "curl" upwards in the cell.  The giveaway though is that their tracheal tube (throat tube) is very visible in the larva worm.

EFB can be treated with Terramycin, same as AFB, but it usually doesn't need treatment unless the colony just isn't going to make it on it's own and collapse.  It's worth noting too that Terramycin cannot be given to bees while honey supers are on the hive or for six weeks prior to collecting honey intended for human consumption.

Another infection of keen interest these days is Deformed Wing Virus (DWV).  DWV causes all kinds of problems for bees, besides just deforming wings that prohibit some bees from ever flying.  Here's a good video by TheOhioCountryBoy showing a bee with classic, visible, DWV symptoms: http://www.youtube.com/watch?v=tyxvHNzlplU

DWV seems to prefer reproducing in the bee's brain, which can lead to erratic behavior (bee rabies?) and functional control, including being able to fly or find their way home.  I recently read in an April 2011 article of The American Bee Journal, by Randy Oliver, of some additional research by Deborah A. Delaney, Jennifer J. Keller, Joel R. Caren and David R. Tarpy (2010) that seems to indicate that DWV may be affecting sperm production in drones and/or the ability of queens to store sperm.  I haven't been able to get my hands on that publication just yet, but I hope to find it and digest it for myself sometime soon.  For now I'm just taking Oliver's word (and it's pretty solid) for it.

The main problem with DWV is that it's an RNA virus.  RNA viruses are especially tough because they morph and transform so quickly.  Unlike DNA based viruses, that are VERY GOOD at making copies of themselves, RNA viruses are very sloppy at it.  The good and bad news in that is, they make lots of bad mistakes.  But every once in a while, since there are billions and trillions of them out there in the millions of colonies around the world, they make a mistake that can have lethal results; allowing them to do great harm and ravage a colony, apiary or worse.

Of all these bee diseases and pests, Varroa is the greatest of all problems.  Varroa by itself can be dangerous but adding to those troubles, it allows opportunities for many other diseases to gain an upper hand they might not otherwise be able to gain, throwing the balance out of things.  Varroa attaches and secretes an immune system inhibitor in the bee.  This means the bee's immune system is suppressed and not as effective at fighting back diseases as it normally would be.  Already the bee is now more susceptible to these other disease invasions in it's body, just from the bite.  The wound will now stay open for a very long time, in bee years, allowing an opportunity for other pathogens to enter.  But even more dangerous than entering in an open wound, they can travel with the mite and enter the bee when Varroa mite sinks it's Destructor fangs into the bee.  As the host fades and dies the mite transfers to a new victim and infects it as well.  Therefore fighting Varroa should be priority number one.

The best thing that can be done to fight Varroa, is to start with good hygenic stock.  There is a strong movement out there among queen growers to do just that.  There are several selection criteria for determining "hygenic" traits.  You'll hear much about Minnesota Hygenic, Varroa Sensitive Hygenic (VSH), Russians etc.  But also you'll hear it in less technical terms.  Everytime you hear a "natural" beekeeper talking about not using any chemicals and letting the bees do their thing, they are allowing Darwin's natural selection to take place and letting bees that have a natural ability to fight Varroa, pass those traits on, or die from their inability to do so.  (this is the same process that happened over a hundred or more years, naturally, leading to the now famed Russian strain of bees we hear so much about)

That having been said, I personally tend to tell NewBees to go ahead and treat their bees the first two years, if they need to, with formic acid (present naturally in honey) for mites and Fumigilin for Nosema.  (Nosema is the second deadliest thing to watch for, after mites)  The reason I tell them that has little to do with the bees themselves and everything to do with building a NewBees success and confidence.  I want them to be successful and not frustrated in that critical first year, which includes a successful overwintering and second Spring.  If you can get them over that critical hump, their interest in the bees seems to grow by many orders of magnitude.  At this point if they have some set-backs or failures, they have some confidence to be able to build back up.

I personally don't use any treatments, except an occasional Spring dose of Fumigilin for Nosema.  I can accept some losses, where some can not.  I rely heavily on hygenic stock.  I made a personal decision to use Minnesota Hygenics a while back and I've stuck with it every year since then.  You will find that hygenic stock also seems to reduce the amount of AFB, chalkbrood and a few other disease and infestation issues as well.  Hygenics seem to care to the hive and brood much more actively and selecting for those traits and successes, generation after generation, will improve the bee's future.  In nature the selection process would happen on it's own and the bees have been successful at it for millions of years without a beekeepers.  But there's no reason you can't be smart about it and help your own stock along in the process.


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