Honeybee Diseases and Parasites

Your bees are a large investment and precious. If I may liken keeping bees to having children you are concerned with your health. It is important to keep your eyes peeled for disease and parasites to keep your bees healthy. It is not as easy as giving the hive a thermometer and seeing if they are running a fever, but I aim to arm you with the symptoms of major bee maladies to keep your apiary healthy. This is an important article to read and bookmark, because if you miss the outbreak of a major bee malady it could harm your apiary and all of you neighbors apiaries. There are 10 major bee maladies that can throw your hives off track lets cover them and their symptoms and potential treatments. Some of these diseases and parasites deserve their own follow up posts for proper management strategies.

    1. The first, and probably the worst of all bee maladies is American Foulbrood or AFB. If american foulbrood is found in your hive it is most likely a terminal diagnoses for your hive. If you diagnose your hive with american foulbrood or you suspect that you may have american foulbrood you should contact your state agriculture department and or your local beekeeping association. This is such a serious disease you will need to destroy your bees and quite possibly burn your hive. I know what you are thinking, “Scorched earth policy. this guy can not be serious”. Yes friends, sorry to say this but this is really a scorched earth policy disease, like the Russians when Napolean invaded. The bacterial spores can survive for 40 years in honey. Which leads me into my next point about American foulbrood is caused by a spore forming bacteria called Paenibacillus larvae. Larvae are infected by spores present in their food. There are multiple symptoms that point to the presence of American foulbrood, the first is the presence of a horrible smell from the smell of dead and decaying brood. The next thing you will notice is that there will be perforated cappings of capped brood. This is from a gas build up from the decay of the brood. Now just because you see perforated cappings that does not mean that there is American foulbrood this could be the sign of chilled brood from a cold snap or from the activities of hygenic varieties of bees pulling out brood that were potentially sick or infested with parasites like the varroa mite. If you see perforated cappings take a match stick or something similar and stick it into one of the affected cells and mix the contents of the affected cell, and pull it out. If the sticky mass, stretches out and snaps back like a rubber band you most likely have American foulbrood. You can have it tested by a lab to be sure, but this is not a bee disease to play with. There are some prophylactic treatments, and antibiotics, but the bacteria can easily become antibiotic resistant so often times this is not a viable path.
    2. European foulbrood or EFB is the next disease on our list to cover. Even though the name is closely related to AFB European foulbrood is no where near as dangerous. It is a bacterial infection but it is not spore forming like the American foulbrood is, but the half life of the bacteria is several months instead of seven years. The disease is passed to larva in a similar fashion as AFB through feeding infected food to young brood. The dead brood will be coiled in the cell, sometimes in the bellyache position with their belly up. As the bacteria progresses they will turn into a yellow brown color and eventually become a scale at the bottom of the cell. EFB is often present but it presents as a problem during a time when the colony is stressed. Luckily, European foulbrood is not necessarily a death sentence for your hive. It is suggested that you still contact your local agriculture department. There are many ways to treat European foulbrood in your hive. You can get powdered terramycin or oxytetracycline and dust your hives. I know those sound like big words, but oxytetracycline and terramycin are common antibiotics used in agriculture and can be purchased at your local tack and feed store. They may not have powdered varieties of the antibiotic, but they may be able to order it. The simplest and most common remedy for European foulbrood is called the shakedown method. Basically, you are taking your hive and making a shook swarm out of them. You want to have another fresh hive set up and with fresh foundation, and you want to shake all the adult bees out of the hive into the new hive. Be wary not to kill the queen here. The hive will build out the new hive like a newly installed package would and raise new brood that should not be affected by this malady. Any old comb and frames need to be destroyed. You can render the wax if that is something you do with the comb out of your apiary, but that is up to you.
    3. The next up on our list is the Varroa destructor mite, or the Varroa mite. If you have been around beekeeping for any amount of time you have most likely heard of the varroa mite. The varroa mite is probably one of the largest root causes for lost hives. The adult female varroa mite enters into the cell of a bee larva before it is capped and enters in to the pupal stage. The female varroa mite lays eggs inside the cell, typically multiple female eggs and one male egg. The young varroa mites mate with the male varroa mite and feed off the hemolymph (blood) of the baby bee. When the adult bee emerges the varroa mites leave with the bee, attaching to other bees (phoretic mites) or look for cells to reproduce in. The varroa mites can transmit RNA viruses to the adult bee like Deformed Wing Virus or DWV discussed later in the article. The bees can live with the mites during the busy part of the season, because the mites prefer drone brood due to the longer gestation of drones allowing more reproduction cycles to take place. It is when drone rearing quits in the fall and varroa mites take to the worker brood for their reproduction cycle. This also occurs at the same time that the bee population is declining to get ready for winter and to match the reduced nectar flow of the season. There are many ways to check mite loads on colonies and treat the mites if the mite load becomes to high. Thereare chemical and natural treatments that can be used, for instance Varroa Sensitive hygenic genes can be introduced (You can read about me requeening one of my hives with a VSH queen here). One simple treatment is apivar strips. In all reality though to overcome the varroa issue in beekeeeping today this doesn’t due justice to all the facets of varroa management. Check back for an article on integrated pest management and the varroa mite in the future.
    4. The next disease on our list is the Deformed Wing Virus or DWV. This is an RNA virus that presents itself with varroa mite infestations. The symptoms of DWV include damaged appendages, stubby useless wings, shorten abdomen, and potential paralysis of the legs and wings. Symptomatic bees may only have a 48 hour lifespan and are typically expelled from the hive. Deformed wing virus can be present in the absence of mites and is passed orally to other adult bees and to brood during feeding. The best medicine for DWV is a dose of prevention. That prevention is monitoring mite load and hive health. Before the mite load gets to infestation levels they should be treated, this will prevent the spread of DWV from getting to epidemic levels within the hive.
    5. Coming in at number 5 on our list of bee diseases is the Sacbrood virus. With the sacbrood virus the bees die prior to pupation. They may be in uncapped cells or partially capped cells where nurse bees have chewed the capping off of the cell. The larva will be typically be vertical in their cell since they were either just getting ready to enter pupation or already were in pupation The larva will have a shrunken head and the body will look like a sack filled with fluid, hence the name sacbrood.  Luckily the way to correct this issue is to requeen your hive, this is not a terminal disease for your bees. Read this article you need information about requeening your hive.
    6. Wax moths are coming in at number 6 on our list. Wax moth lay eggs in the bee hive, and the wax moth larva tunnel through the comb eating honey, beeswax, pollen, and in some cases honeybee brood. The tunneling activity is a defensive activity to prevent the honeybees from destroying them. Wax moth larva can quickly devastate a hive, leaving behind a web like filled with feces and debris. A strong hive can easily defend itself from wax moths because honeybees will attack adult moths before they can lay eggs in the hive. Weak hives are susceptible to wax moth infestations. If you notice signs of wax moths remove any affected comb. If it is destroyed then it is best just to clean out the foundation clean it and replace it with a fresh frame. If you catch a frame with just a little damage, freeze it overnight to kill any eggs and larva and it can be placed back into the hive. Another thing to look out for when considering wax moth damage is storing your equipment. If you are storing drawn comb through the winter wax moths may find their way into it and destroy that valuable drawn comb. One of the easiest ways to store your hives is to use PBD crystals commonly know as moth crystals. Just dust your equipment before storage and boom you are good for the off season.
    7. Another troublesome parasite that you will most likely see in your hive is the small hive beetle or SHB. In a large portion of the USA it is probably that you see small hive beetles in your hive. Luckily, other than general discomfort of knowing that you have a parasite in your hive, most of the time your hive will take care of hive beetles. The damage from hive beetle infestations are not caused by the beetles but the larva of the hive beetle. These larva tunnel through the comb eating honey and pollen. Their feces causes the honey to ferment giving off a smell. Does this sound similar? It should it is the same action taken by the wax moth larva. If the comb has already been destroyed, remove it from the hive and replace with a fresh frame. One of the biggest things that you can do to prevent small hive beetle infestations is to keep a strong hive. However, it has been discovered that nematodes introduced into the soil can be a great way to control small hive beetle numbers.
    8. Nosema comes in at number 8 on the list. Nosema comes with a list of non specific treatments or causes of onset. Nosema is a fungal parasite of the honeybee causing dysentery. This is identified by yellow streaking on the outside of your hive. This is typically seen after bad weather like when cleansing flights happen in the spring. Typically, nosema causes issues for the worker bees since the queens attendant bees are rarely affected by the spores. In saying that, if the queen contracts nosema she may be shortly superseded because it can affect her ovaries so she may not be able to lay eggs as well as she did before. There is a treatment available as a prophylactic to give to the bees in late fall and early spring, it is Fumagilin-B. This is added to your honeybees sugar syrup for their fall and spring feeding and reduces the amount of nosema spores in the hive, and bees.
    9. Tracheal Mites are an internal parasite to the honeybee, living and reproducing within the trachea of honeybees. This affects the bees ability to breathe, fly, and reduces life expectancy. The wings of the bees may be disjointed and you may see them outside your hive walking on the ground unable to fly. The tracheal mites are microscopic so it may be hard to diagnose, but barring any other observable maladies to your bees it may be due to tracheal mites. Tracheal mites will rarely kill a hive in the summer, it is when the infested hive goes into winter with a reduced life expectancy and not enough bees to replace the dying bees. Tracheal mites can be treated with menthol crystals. Use 2 ounces when the whether is above 80 degrees. Place them in a perforated package on your bottom board for 28 days. Make sure there is not a nectar flow going on if treating for tracheal mites due to the possibility of contaminating your honey.
    10. Chalkbrood and stonebrood round out our list for today both of these are fungal infections affecting honeybee brood. You may notice hard mummified brood on your landing board, these will be hardened. The spores of the fungus begin in the gut of the bee larvae eventually consuming the entire body of the bee. What you see when you find them on your landing board is the hygenic nature of the bees cleaning out the brood nest so that the queen can continue laying eggs. Hives can recover from chalkbrood and stonebrood if they are strong enough and have enough stores. Chalkbrood may be more common during wet springs so increased ventilation should help clear it up. I have read about adding bleach to your sugar syrup in small amounts but I would steer clear of this method. If chalkbrood is a consistent problem look into requeening your hive. Stonebrood has no chemical treatment, and if any comb is heavily infested with stonebrood it is advised that you remove it from the hive to prevent further infection.

    Hopefully, this guide will help you answer questions about any honeybee diseases you may encounter in the hive and to better prepare to take care of your bees. One of the things you should take away from this guide is that an ounce of prevention is better than a pound of cure. The biggest thing you can do to prevent this is to keep your hives strong and keep a sharp eye out for any honeybee diseases or parasites. If you have any feedback I would love to hear from you.


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