All beekeepers have a need to deal with pests at some point. Generally, mites come to mind when beekeepers think of pests. But while mites are at the top of the list, there are a host of other pests with which we beekeepers must contend.
In general, pests can be defined, simplistically, as “something that bothers bees”. But it’s a long list and includes bears, skunks, mice, yellow jackets, wax moths and mites. And there’s one more “pest” – close to home – you may not have considered.
Let’s dive in….
Wax moths
Let’s start with a look at wax moths, which enter hives to lay their eggs and can create significant damage to comb. The larva tunnel through comb towards brood and shed their exoskeletons, which contain proteins essential to the larva’s development. The webbing wax moths deposit on comb is one of the first clues for the beekeeper regarding their presence. Looking more closely you will also notice cocoons and wax moth poop.
With a magnifying glass, look closely at the larva to determine if you have wax moth or small hive beetles. In the Pacific Northwest, where I’m located, we do not yet face the threat of small hive beetles. But all beekeepers should be able to discern the difference between these two pests. Under a magnifying glass, you will find that the small hive beetle has a long row of spines along its back, whereas the wax moth does not.
The best way to prevent an infestation of wax moths is an approach that has many other benefits, namely yo maintain a strong colony. In such a colony, bees will remove the moth larva and repair damage to the comb. By comparison, a weak colony be unable to combat the damage done to comb and loss of brood.
Beekeepers should also be careful to store equipment properly. Stacking boxes in a criss-cross fashion, to allow in light and air, is the good way to store them. Frames of honey frozen at 18 degrees or lower for at least 4 hours will destroy both wax moth eggs/larva in addition to mites. The frames should then be stored in sealed containers.
Skunks and bears
There are, of course, some bigger pests. Skunks are found in most areas and will often leave a calling cards of scat, in front of the hive. When the scat is filled with bee remains it may resemble cuds of chewing tobacco. You may also find scratches on the landing board, reduced bee numbers and defensive bees.
Many beekeepers choose not to poison or trap and, instead, will put a strip of carpet tacking (nail side up) on the landing board. When the skunks reach up to landing board to eat the bees they get an uncomfortable welcome! It also helps to have your hives at least 18 inches off the ground.
Most beekeepers (in fact, most laymen!) are aware that bears are very destructive once they get to a hive. Once they have found and reached your colonies, it is all but impossible to keep them out. They are a serious threat and extensive preventiative precautions must be taken if you keep hives in bear country.
Bears eat honey much like the “pooh bear” in the children’s bed time story, but more often than not they are after the brood and the associated protein. They will tear apart and destroy equipment to get to it.
Your best defense is to move your hives to a location that does not have bears. But if that is not possible you will likely need to install a sturdy electric fence. A typical fence will have 3 wires and to be effective it must remain electrified. Colonies will also need to be located an adequate distance from the fence.
Mice
Mice will enter hives in the fall or early winter when night time temperatures approach freezing. They cause extensive damage to both comb and wooden ware and can devastate a colony by feeding on bees, brood and honey stores. Mice can – and often do – totally destroy weak colonies. Their nests, urine and droppings are not simply an irritant to the bees but constitute a mess for the beekeeper to address in the spring.
The most effective ways to prevent a mouse infestation include the use of entrance reducers, mouse guards and/or closing the entrance with half-inch mesh. It also helps to keep weeds down and place the hive on a stand well off the ground.
The Unknown Pest
When taking up into beekeeping most of us don’t consider other humans to be a pest. But we are rapidly staking a claim to the number one pest of all!
Incredibly and very sadly, teenage vandalism of hives has been rising as well as the theft of colonies. As the value of bees and the associated equipment has risen there has been a related increase in the theft of hives.
The best advice for avoiding these problems are to keep your bee hives out of sight and, if possible, behind a locked gate.
Yellow Jackets
Late summer and early fall bring one of the more troublesome pests with which beekeepers must deal. Yellow jackets become bolder as the season progresses. By late summer they are often found picking up dead bees from the landing board on the ground in front of hives. They will then progress, entering the hive can killing weak colonies and seriously damaging strong colonies.
A sure sign yellow jackets are entering your hives is finding bee body parts, such as wings and legs, on a sticky board. Yellow jackets prefer the soft body parts.
Spring is the time to trap as many yellow jackets as possible because these are queens – each one eliminated is a complete yellow jacket nest a beekeeper won’t have to deal with. Eliminating nests is another solution to the problem. Beekeepers often hang yellow jacket traps, of which there are many variations, but while they help, they generally will not eliminate the problem.
By late summer you may want to consider reducing entrances and combining weak hives with strong ones.
Mites
Mites are arthropods. They have eight legs, are related to the tick and more than 50,000 species have been identified. Tracheal mites are one of two species of mites that are especially harmful to honeybees. The tracheal mite is microscopic and resides in the honey bee’s respiratory system. It is capable of infecting all bees in the colony including the queen.
Tracheal mites infest the thoracic tracheae of an adult honey bee. The mites enter the trachea by the spiracle openings on the side of the bee. They lay one egg per day and newly emerged young bees are most at risk because the mites seek them out first.
Symptoms of an infestation include bees crawling in front of the hive and crawling up stems of grass, because they are unable to fly. But these symptoms can also be confused with symptoms of other problems.
The best way to confirm tracheal mites is to send a sample the USDA Bee Research lab in Maryland.
Bee Disease Diagnosis, Bee Research Laboratory
Beltsville Agricultural Research center – East
10300 Baltimore Ave.
Bldg. 306 Room 316
Beltsville, MD 20705
Grease patties are the primary treatment and it is suggested that once tracheal mites are confirmed a grease patty should be in the hive on a year round basis. Four parts powdered sugar + 1 part Canola oil (you can use Crisco) and it should be firm, so as not to drip through the frames when placed upon the top bars above the brood nest.
Varroa Destructor
Varroa Destructor has been impacting honey bee health in the United States since 1987 and as a beekeeper it must be understood that you are also a mitekeeper.
Mites are in all hives and you will never get rid of them. The idea is to manage them, not attempt to eradicate them. Varroa are host-dependent and an understanding of varroa biology is essential. The more you educate yourself about the life cycle of the mite and how it interacts with Apis mellifera, the European honey bee, the more successful your beekeeping efforts will be.
Knowing the bees and varroa life cycle helps the beekeeper understand how to control this pest.
1. Worker bee cells are capped on or about day 8. Just prior to the cell being capped the female mite crawls into the cell and embeds in the brood food.
2. After the cell is capped, the mite parasitizes the prep-pupa
3. This foundress mite lays her first egg 60 hours after the cell is capped. The first egg is unfertilized and produces a male that matures in 5-6 days. Female eggs are then laid every 30 hours thereafter.
4. The male mates with one or two of his sisters before dying. He does not leave the cell. When the bee completes metamorphosis and emerges from the cell the mother and daughter mites emerge and soon begin the cycle over again. Typically one (occasionally two) mites are produced in a worker cell. One to three mites can be produced during the longer drone development cycle.
The foundress mite and her young will spend the next few days looking for new cells to invade. They will attach themselves to adult bees and are often carried to other colonies as well.
What are signs of Varroa in your hive?
1. Bees falling out of the hive and exhibiting the inability to fly. Not just a few but tens of bees. This can be symptomatic of other problems as well so look for other signs.
2. Check the capped brood. There is a stage in which the healthy capped brood has a hole in the center of the cap just prior to when the bees complete the capping process. These holes are directly in the center of the cell. Capped cells that have perforations off of center have varroa.
3. Spotty brood pattern is another sign of mites.
4. Bees that exhibit deformed wing virus and soon die are a clear indicator of mites.
5. Hold up a frame and look for white deposits of guanine on the top of the brood cells. Varroa defecate in the same place and these white deposits build up and are easy to see.
Sampling for mites
The gold standard for sampling for mites is the alcohol wash. The beekeeper collects 300 bees (½ a cup) in a jar with a mesh screen over the top and then pours in alcohol before screwing on the lid. The jar is vigorously shaken before removing the lid (screen remains on) and pouring the liquid out into a tub containing a white paper towel. The mites show up clearly against the white background making it easy for the beekeeper to take a count.
The drawback of course is that this method kills the bees. Another approach is the sugar shake. Collect 300 bees as before making sure not to get the queen but this time instead of alcohol use a couple tablespoons of powdered sugar pushed through the mesh over the top of the jar. Vigorously shake the jar for 30 seconds and then set it in the sun for a minute.
Then shake vigorously one more time for another 30 seconds and set the jar back in the sun for at least 30 seconds more. Then turn the jar upside down with the screen still on the jar and shake the powdered sugar onto a wet white paper towel. The wet towel will melt the powdered sugar and the mites will be easy to see. Done properly some bees will be killed or injured using this sampling method but most will survive.
There is a third way. Some people use a sticky board to collect a 24 hour mite drop. A faster version of this is to sift powdered sugar over the cluster of bees through a sieve (outer cover and inner covers are off of the hive obviously), brush it off the top bars and then close up the hive. After ten minutes you pull the sticky board and count the mites.
This approach is a quick way to get a rough picture of the mite situation within the hive. I like to use it in early spring when I don’t want to leave the hive open long enough to collect a sample of 300 bees. It will not give you a percentage of mites (discussed below) but experience has shown that early in the spring you will find you either have mites or you don’t. A count of 0 to 1 or maybe 2 mites shows little problem versus a count of eight, ten or more which is definitely a problem in early spring.
How many mites are too many?
When getting a mite count using the alcohol wash or sugar roll you divide the number of mites by 300 (number of bees). This gives you a percentage. In the spring a good count is 1 percent or less. In late summer a mite count of less than 3 percent is desirable. Numbers higher than those indicate that mites are a problem and should probably be treated.
Treatments vary by time of year and the type of treatment so the beekeeper should become knowledgeable of the various types of treatment and when they can each be used.
What happens if the mites are not controlled?
In many cases the colony will be destroyed by the mites if they are not dealt with. While each beekeeper makes their own decision with regards to treatment, there are some other considerations to factor in when making the decision to treat or not, that may not initially be obvious.
A colony destroyed by mites is often referred to as a mite bomb. The hive is literally exploding with mites. Some of the bees, possibly up to a third, will leave the hive before dying and carry mites to other colonies.
But the greatest impact will happen when other bees raid the dying colony for its honey and bring the mites back to healthy colonies. Numerous colonies are lost to mite bombs every year. So please be considerate of other beekeepers and the potential impact to feral colonies.
There is nothing more frustrating than caring for your colonies throughout the year only to watch them be destroyed by mites from neighboring colonies that were not properly cared for.
For those considering “treatment free” beekeeping, an excellent rule of thumb to use when deciding if to go treatment free or not is to answer a simple question. Am I in town where my bees would destroy other colonies or am I located in an isolated area where any mite bombs I create or allow will have little impact on other healthy colonies?
Summary
A beekeeper must be aware of and deal with many pests that will negatively impact their bees if given a chance.
Carefully dealt with, pests do not need to lead to the loss of your colonies and if proper attention is paid to the potential of each pest, you too can join the ranks of those who rarely lose colonies.
