Diseases and Pests of Honeybees
Every beekeeper should keep abreast of pests and diseases that pose a threat in this area, and the latest in treatments and preventive measures. Below are some recent resources. Treatments and recommendations change often, so be cautious in using information that is more than a year or two old.
The top problems in our area include
- Varroa mites
- Tracheal mites
- Wax moths
- Foulbrood
NC State University maintains Beekeeping Notes -- see the entire list of available notes here
NCSU Beekeping Notes
A new note on Diseases was added in February of 2006. It is 12 pages and includes several color pictures, so the size is over 5 MB. It's like getting a free textbook.
NC State Beekeeping Note 2.01 Diseases of the Honey Bee (PDF, 5 MB)
Varroa Mites - (Varroa jacobsoni)
Varroa mite is the top problem for honeybees in our area today. Numerous treatments are available, and some beekeepers swear by techniques such as screened bottom boards or culling drone brood. Some say their bees are "resistant" to mites and do not treat their bees with medicine.
BUT -- every responsible beekeeper should AT A MINIMUM know how to test his/her bees for Varroa infestation. Here is the NCSU note on testing and treating for Varroa:
NC State Beekeeping Note 2.03 Managing Varroa Mites
If you do treat for mites, accepted practice is to rotate treatments, using different ones in spring and fall, to discourage resistent mites. All treatments must be used to the full extent according to the directions (often 7 weeks) and then be removed from the hive 2 weeks prior to installing the honey supers. So calendar management is important.
Here's a recent article from Bee Culture summarizing the latest treatments.
Mite Away 2 Treatment Video
Tracheal Mites - (Acarapis woodi)
Detecting Tracheal mites is pretty much impossible for the small beekeeper, and treating for tracheal mites is very easy. So consider treating your bees once or twice a year for this pest unless you believe your bees are resistent to this mite. Menthol is the preferred treatment, see the NC State notes or a beekeeping supply catalog. Using the methol crystals is easy, but there is another method involving shop towels and canola oil, or sugar and vegetable shortening. More on tracheal mite treatment
Wax Moths - (Galleria mellonella & Achroia grisella)
Wax moths are a nuisance and are kept in check by a strong hive, but can make a real mess of a weaker hive and ruin wax in a hive which has died. The first preventive is to check your hive often enough to know they are ok. The most common damage from wax moths is to frames which have been removed from the hive. When you have extra wax frames, from honey supers or extra brood frames, they should be stored in one of two ways to prevent damage from wax moths. First, store them outdoors in such a way that they are protected from weather but have plenty of fresh air and light to circulate around them. Use scrap wood as spacers to allow circulation between the boxes. Or, place moth crystals (NOT moth balls) on a paper plate, on top of a stack of 5 supers, and wrap the whole stack in plastic. The frames need to be aired out for a couple days before placing them in a hive. Any time you suspect an infestation of moths you can kill them by placing the frames (without the bees) in the freezer for 48 hours.
Small Hive Beetle - Nitidulid beetle: (Aethina tumida)
Small Hive Beetles have spread throughout our area and are another nuisance that the bees can often control on their own. You may see a few adult beetles now and then but they are not cause for concern. However if you see hive beetle larvae that may mean the bees are not keeping up with the problem, and you may have to help. There are few chemical controls for hive beetles and the available ones are extremely toxic. Study the catalogs and magazines, and ask for help from someone who has used them. In some cases a pesticide license may be required. The best defense is to keep strong hives -- weaker hives can be combined to help them avoid many of these problems. Keeping hives in the sun and more than 10" up off the ground also makes life difficult for hive beetles. Refer to the NC State Beekeeping Notes for more info.
Postscript on Small Hive Beetles: they have been known to ravage wax frames which have been stored out of doors (see Wax Moths, above) IF the frames had any brood or pollen left in them. These frames would be better off stored with moth crystals.
Nosema - Microsproidian: (Nosema apis)
Nosema is an infection comparable to dysentary, causing a type of "bee diarrhea." It is treated (or prevented) with a dose of Fumadil-B in sugar syrup, one or two doses in fall and spring.
American Foulbrood - Bacterium: (Paennibacillus larvae)
Foulbrood is a serious but thankfully uncommon disease of honeybees. It is a highly contagious disease spread through spores. It can be identified visually and also because the hive may smell like old nasty gym socks. A full-fledged case often requires the hives and equipment be burned. It is the responsibility of each beekeeper to ensure his/her hives are free of this disease and avoid spreading it to his/her neighbors. The state bee inspectors offer a service where they take infected equipment to Raleigh to be processed in a special chamber, but as the wax must be destroyed, it's not always worth the trouble. Until recently the accepted practice was to treat twice a year with antibiotic to prevent the foulbrood spores from blooming -- however the treatment does not kill the spores and failure to detect the presence of spores can lead to spreading the disease. The recommended practice now is to be vigilant about inspecting for the disease; for a light case, destroy the comb but save the bees and treat them with Terramycin; for a heavy case, destroy the equipment and bees. This means you must know how to recognize the disease early and call for help from the bee inspectors immediately.
European Foulbrood - Bacterium: (Mellisococcus pluton)
European foulbrood is somewhat less serious than the American version but still a problem for bees. Infected comb should be destroyed and the bees treated with Terramycin.
Sacbrood - (Virus)
Chalkbrood is often associated with hives under stress or when the brood has become chilled. The beekeeper should resolve the underlying problem and possibly requeen the hive.
Chalkbrood - Fungus: (Ascosphaera apis)
Chalkbrood is often associated with hives under stress or when the brood has become chilled. The beekeeper should resolve the underlying problem and possibly requeen the hive.