Beehives: Pests, Diseases and Other Problems
In The Beginner’s Guide to Beekeeping (Voyageur Press, 2013), veteran beekeepers and farming professionals Daniel and Samantha Johnson walk you through the dos and do-nots of raising a happy and healthy hive of honey bees.
The following excerpt from chapter 4 “Pests, Diseases, and Problems,” discusses issues such as parasites, animal pests and colony collapse as well as strategies to help save your bees from succumbing to these problems.
You can purchase this book from the Capper’s Farmer store: The Beginner’s Guide to Beekeeping.
We know you want to do the best job you can as a beekeeper, and part of that job includes being able to recognize the characteristics of a thriving, healthy hive in comparison to a hive that is suffering from disease or pest infestation. By educating yourself about the different issues that can affect your colonies, you may be able to spot a potential problem before it becomes harmful, giving you the chance to provide treatment if necessary.
On the other hand, don’t allow yourself to be overwhelmed with fear in regard to the safety of your colonies. Chances are good that your hives will thrive and that all will be well in honey bee land. We just want to provide you with a basic overview of pests and diseases so that you have knowledge of them and don’t freeze in horror when someone mentions the phrase “Varroa mites.”
There. Now—keep reading!
Parasites and Pests
Bees belong in your hives—small hive beetles don’t. These African-native pests were first discovered in the United States in the late 1990s, and these troublesome creatures can wreak havoc on a hive if left to multiply. If high numbers of beetles are present in the hive, the bees may simply abandon it. While you can treat the hive with pesticides, another option is to purchase beetle traps and add them to your hive. This can be an effective way to control the population of beetles in your hives. The number of traps you’ll need might depend on your location; for instance, beehives in southern regions will require significantly more traps to assist in controlling the problem. Remember, local beekeepers are the best source of advice when dealing with pest problems in your area.
Note: Small hive beetles are said to be particularly fond of pollen, so if you’re using a pollen trap, it’s quite possible that you’ll find small hive beetles in your trap with the pollen. A large number of beetles present in your pollen trap could indicate a high level of infestation in your hive.
The presence of Varroa mites in a hive is a potentially serious issue, but not a situation over which you need to immediately panic. The reason you need to be cautiously concerned over Varroa mites is because they can infect your bees with a virus that—simplistically speaking—affects wing development and leads to deformation of the bees’ wings. Because Varroa mites are so prevalent in the United States, you may occasionally discover that one or more of your hives has a few of these pests in residence. While we would all love to have 100 percent mite-free hives, a more practical goal is to maintain a low level of mites. You can accomplish this by monitoring your hives regularly for the presence of mites and then treating accordingly on an as-needed basis if the mites become too populous. There are many methods for tracking the number of mites in a hive—such as detector boards and visual inspections—as well as a variety of treatment methods—both organic and chemical-based— that you can utilize to minimize the mite population. Beekeepers in warmer climates tend to have more difficulty with Varroa mites than beekeepers in colder climates.
One easy (and noninvasive) way to monitor the number of Varroa mites within your hive is to place a sticky board under the screened bottom board of your hive. You can purchase this type of sticky board from a beekeeping supply company, or you can make your own by using a thin white plastic sheet, a sheet of white cardboard, or something similar. Make your board sticky by lightly covering it with cooking spray, Crisco, oil, petroleum jelly, or some other sticky substance. Slide the sheet into the hive, underneath the screened bottom board, and leave it there for twenty-four hours. After this time has elapsed, remove the board and count the mites that have fallen through.
If you’ve collected more than 50 in just one day, then it’s probably time to treat your hive to minimize the presence of Varroa mites. But if you’ve collected fewer than 50 in one day, then your infestation levels are probably acceptable and you can forego treatment for the time being. Keep an eye on the Varroa mites, however, and don’t let their presence get out of hand. These sticky boards can also be used to monitor the prevalence of small hive beetles in your hive.
Tracheal (acarine) mites are far less widespread than Varroa mites but can still prove to be problematic for beekeepers. Tracheal mites infect the trachea of the bee, hence the name. Again, it is the level of infestation that you must be most concerned with. Heavily infested hives can become quite weak due to loss of bees, and weak hives can be lost completely. Treatment can be accomplished with menthol pellets; requeening of the infected hive is another proven way to reduce the presence of tracheal mites.
We are all fond of butterflies and moths when they’re floating around in the air outdoors, looking pretty. But wax moths inside your beehives? That’s another story entirely. Wax moths are extremely destructive, and while strong hives will usually be able to withstand the attack of the wax moth, weaker hives sometimes cannot. The moths enter the hive, lay their eggs, and leave, but the young wax moth larvae cause great destruction to the hive and leave a sticky white web-like material throughout the hive. Prevention, by maintaining strong, healthy hives, is the best way to reduce the presence of wax moths in your hives. You can also help protect your hive’s entrance with a screen that will keep wax moths out while allowing bees to enter safely.
Another prevalent parasitic disease that strikes honey bees is Nosema. There are two varieties of this gut disease, Nosema apis and Nosema ceranae. Nosema apis often strikes during the winter months when bees tend to stay in the hive and don’t make enough cleansing flights. The troublesome parasite injects its pathogen into the gut of the bee where the spores reproduce and are expelled in the feces of the bee. The disease can spread quickly at that point. If you see dead bees outside around the entrance to their hive, you should definitely pay attention because this can be a sign of nosema. Another even more characteristic sign of nosema is the presence of streaks of brown or yellow bee feces on the outside of the hive.
Nosema ceranae is considered to be a more serious threat, often causing a bee colony to die quickly. Nosema ceranae is a year-round risk to all regions.
There are some potential treatment options (including some organic options); the antibiotic fumagillin can be used as a preventative measure. It is particularly important to maintain good beekeeping management practices in order to ensure that your hives remain healthy enough to combat or withstand these problems.
Now you get to meet a couple of acronyms: AFB and EFB. Rather than have you strain your brain in a gallant attempt to figure what those letters stand for, we’ll simply tell you: American foulbrood (AFB) and European foulbrood (EFB). Both of these conditions are bacterial diseases that afflict the young larvae (brood) in the hive, although AFB also affects the pupae. While there are a number of similarities between the two diseases, AFB is considerably more serious than EFB and can result in the complete loss of an entire colony or even your entire apiary.
It’s not always easy to spot a case of AFB unless you know exactly what you’re looking for, but discolored, punctured, or sunken caps are suspicious. You will likely notice an extremely foul odor inside hives infected with AFB or EFB, although the smell is stronger in cases of AFB.
Another effective way to determine the presence of AFB is to test for ropiness. Find a suspicious-looking punctured cell, take a small stick (a toothpick works well), and stir around inside the cell. Then pull the stick out of the cell. If there is a stringy, mucous-like substance between your stick and the cell (like a rope), then this is highly indicative of AFB infection.
Symptoms of EFB include uncapped larvae that are yellowed and twisted, rather than the usual healthy larvae that are pearly-white and C-shaped.
Some beekeepers choose to treat their colonies with the antibiotic Terramycin as a preventive measure, but others are leery of introducing antibiotics into their hives. If you have a colony that is infected by AFB, then you may need to eliminate the hive and burn the equipment to avoid spreading AFB to other bees. While you can attempt to treat colonies that are already infected with AFB, the disease never goes away, and it will come back after treatment ceases.
Thankfully, EFB is milder and less serious. You can treat EFB fairly successfully with Terramycin, and many cases resolve without treatment.
Here’s another disease that you won’t like reading about. Chalkbrood is the term used to describe a fungal disease that infects brood and causes it to become “mummified” (the term “chalkbrood” refers to the brood’s similarity in appearance to a piece of chalk). You’ll be relieved to know that chalkbrood is far less dangerous than some of the other diseases that can affect your hives, and sometimes the bees in the colony are successful in eradicating the disease by themselves without assistance. If you’d like to give them a helping hand, then requeen the affected hive; this is said to be an effective way to minimize or eliminate the fungus.
Exactly as its name implies, chilled brood can occur when the hive is too cold or when there are not enough adult bees in the hive to maintain a suitable level of warmth. The brood may perish from the cold temperatures. Spotty brood , on the other hand, does not refer to a problem with the brood itself, but rather refers to brood that has been laid in a random or disorganized fashion. This can sometimes signal the presence of a disease in the hive, but it can also occur if the queen is failing. In the latter case, requeening may be necessary.
Here’s another acronym that you’ll likely hear a lot about: CCD , which is short for Colony Collapse Disorder . It is a poorly understood phenomenon that has caused beekeepers plenty of concern in recent years, as incidences skyrocketed of bees disappearing from their hives. The Agricultural Research Service of the United States Department of Agriculture describes the symptoms of CCD as follows: “Very low or no adult honey bees present in the hive but with a live queen and no dead honey bee bodies present. Often there is still honey in the hive, and immature bees (brood) are present.” Some research has pointed to Varroa mites as a possible culprit in the CCD mystery, but researchers are still searching for answers to this apicultural conundrum.
As if beetles, mites, and moths weren’t enough to worry about, there are also animals that can cause trouble. Let’s take a quick look at some of these animal pests, and then we’ll look at some ways to prevent animal damage.
Meet the Animal Pests
It’s not a joke from a cartoon—bears really do like breaking into beehives and stealing honey. Bears seem to have a particular fondness for honey and larvae, and they have the strength and brawn to break into your hives and get them. A bear can easily tip over and destroy a hive, ruining months of effort by you and your bees. If you live in an urban location, you probably won’t have as much trouble with bears.
Raccoons have been known to climb up on top of a hive, remove the outer and inner covers, and even pull out a frame or two of honey to drag off and eat, upsetting the bees and ruining some of your crop.
Skunks aren’t particularly interested in your honey—they just want the bees! Skunks will creep up to the hive—usually at night—and begin scratching the outside. The scratching alerts the bees that are on guard, and they come out to investigate, only to unfortunately be snatched up by the skunk, who doesn’t seem to care much about getting stung.
Okay, so it’s clear that animals can cause big trouble for your bees—but what can you do about it?
If you know these animals are predictably and routinely traveling past your hives, your first step is to consider moving your hives to a new location. It isn’t really the animal’s fault if you’ve inadvertently set up near their traveling route, and your beehives don’t need to be an unnecessary temptation. However, if your hives are up in your yard or close to your buildings, it is likely that the animals are coming specifically to check out the hives, and this needs to be deterred. Bears, especially, need to be discouraged, because once they’ve stolen honey, they’ll keep coming back again and again for more.
A simple electric fence is usually the easiest way to deter predators. It doesn’t have to be elaborate—simple metal posts and insulators—along with a few strands of electric fence wire and a charger—are usually all that’s needed. You can find all of these components at farm or livestock supply stores or through catalogs. You probably won’t need a very strong power supply for your fence; you’re only enclosing a relatively small area, and all you’re really trying to achieve is a small pop of electricity to discourage the animals. If your hives are close to a power source, you can buy a power supply that simply plugs in, but if not, there are solar-powered fence chargers that do a fine job of powering a small fence. An electric fence is an excellent way of stopping all of the animal pests mentioned above.
In the case of raccoons, putting a heavy object on top of the outer cover (a rock or a brick, for example) is often enough to prevent the raccoon from prying off the lid.
One other note: be sure to tidy up your apiary after working in it. Don’t leave empty open hive boxes or frames lying about—or bits of comb or anything that might smell like honey. Leaving these things around is just inviting trouble.
Reprinted with permission from The Beginner’s Guide to Beekeeping by Daniel and Samantha Johnson and published by Voyageur Press, 2013. Buy this book from our store: The Beginner’s Guide to Beekeeping.
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