Bee a boss: How to banish small hive beetles from your hives

Inside: Find out how to control small hive beetles in your apiary. Learn how to prevent infestations and protect both your bee colonies and honey crops. Above: Small hive beetle adult. Photo by Jesse Rorabaugh/iNaturalist

Charlene, a beekeeper in Georgia, described the nightmare she discovered in her only hive. After a summer trip to Nashville, she returned to find foul-smelling honey reminiscent of acetone pooling on the varroa drawer. From there it had sluiced off the edges in viscous globs that rolled in the dirt and settled atop the soil like cocoa-dusted bonbons. Inside the hive, honey frames, slimy and smelly, glinted white with larvae slithering into piles that mounded and flattened like waves on a beach.

Although Charlene purchased used equipment, she had cleaned and scorched every piece to prevent foulbrood. Still, the boxes and frames contained cracks and crevices common in older equipment. In addition, her county was a hotbed of small hive beetles (SHB) and her hive occupied a shady sanctum beneath two leafy peach trees. She thought the site was heavenly, and so did the beetles.

Bands of beetles nudging north

For a while, the small hive beetle (Aethina tumida), an accidental import from sub-Saharan Africa, stayed in the southern states. But as warming trends spread, so did the fortunes of this honey bee pest. A 2019 paper in the journal Global Change Biology¹ warned, “Future scenarios of global warming project a vehement increase in climatic suitability for SHB and corresponding potential for invasion, especially in the temperate regions of the Northern hemisphere.” Not pleasant news for beekeepers.

A combination of soil temperature and soil moisture regulates the spread of hive beetles. That’s because, after 13 days of munching on your honeycombs, the larvae leave the hive in great gallivanting groups to pupate in the soil. During this “wandering phase,” the larvae spill over the hive entrance like lemmings and drop onto the soil to search for the perfect spot to mature into adults.

Although the larvae can travel remarkable distances, suitable soil close to the hive is safest because extensive travel for soft, worm-like creatures is always risky. Toasty yet moist soil, not too compact, is the perfect place to dig.

Soil moisture is critical to pupation because it prevents desiccation of the soft-bodied life forms.² And because warmer soil can shorten the pupation period from about 33 days to roughly 15, beetle populations in steamy soil can expand quickly. As climate fluctuations bring both warmer and wetter summers to many areas, small hive beetles are moving to fresh territory. So what can you do to protect your hives?

Hive beetles exploit the weak and ambush the strong

Beekeepers often compare hive beetles to wax moths because they appear to take advantage of weak colonies with compromised defenses. But others say the beetles can overwhelm even a populous, vivacious colony unless the beekeeper controls their populations. If you plan to establish an apiary in beetle territory, it pays to evaluate your soil type and hive placement.

Other than maintaining strong colonies, beekeepers recommend a suite of control measures, including chemical, mechanical, and biological protocols. In addition, sunlight passed through red acrylic has provided intriguing results in limited tests. Like many other colony threats, including varroa, a program of integrated pest management featuring multiple control measures is most likely to succeed in the long run.

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I sometimes hear beekeepers express their indifference to minor infestations: “I don’t worry about small hive beetles because I don’t have many and my bees keep them corralled and helpless.” That sounds nice, but as tame and contained as those beetles may appear, life is bubbling within their shiny brownish-black bodies. Eggs form, spermatocytes divide, and future generations bide their time in the protected warmth of the hive. Ignore them at your own risk.

The landscape of sun and shade

We know that bright sunlight repels adult beetles, so they choose shaded hives instead. Their preference for shade may relate to reproduction because a beetle’s offspring has a better chance of survival in moist soil, something more common in shady areas.

However, beekeepers report that all-day sun is unnecessary for reasonable beetle control. A few hours of shade is okay as long as the hives receive enough direct sun to keep the surrounding soil dry. As a beekeeper, you must heed the health of your colonies even as you fight the beetles, so never keep your colonies so hot that honeycombs melt and bees flee the heat.

As with other pests and predators, try to find their weak spots and attack them when they are most vulnerable.

Pupation: the weak link in the beetle life cycle

So far, the wandering stage of beetle life has been the primary window for control measures. Because the beetles travel away from the colony for pupation, they are vulnerable to beekeeper intervention.

Beekeepers have treated the soil below their hives with pesticides, spread beetle-eating nematodes, and even paved the ground with concrete or covered it with crushed rock to discourage the beetles. Let’s look at some methods for turning their pupation grounds into the enemy.

Soil turned assassin

We can make the soil beneath a hive hostile in several ways. For example, some beekeepers incorporate salt or diatomaceous earth into the ground. Salt will kill the larval and pupal stages of beetles by desiccation, rapidly drawing moisture from their bodies. Salt will also kill most plants, so if you have something you’re trying to nurture, salt may not be your best choice.

Diatomaceous earth sprinkled under a hive will also kill most small creatures that live there. Made of the fossilized skeletons of little sea creatures called diatoms, the tiny fossils are razor sharp and cut into the larvae as they wiggle through the soil, resulting in death by a thousand cuts. Diatomaceous earth is inexpensive, readily available, and works well, but don’t sprinkle it around anything valuable, such as ground-nesting bees.

Roundworms to the rescue

Entomopathogenic (causing disease to insects) nematodes are another popular below-the-hive treatment for small hive beetles. These tiny roundworms infect wandering beetles in their larval or pupal stages by simply crawling through a natural opening, such as the mouth, anus, or respiratory spiracles.

Two main genera of nematodes are popular for combating small hive beetles, Heterorhabditis and Steinernema. These two groups have different methods of “hunting” for small hive beetles, so sometimes one works better than another, depending on soil conditions. The two most commonly used species of Heterorhabditis crawl through the soil and search for their prey, while the two common species of Steinernema stay in one place, lying in wait to ambush their target.³

In all cases, once the nematodes enter the beetle’s body, they release a symbiotic bacterium from their body cavities into the body cavities of the hive beetles. Although harmless to the nematodes, these bacteria wreak havoc on the small hive beetles, releasing a toxin that kills them in 24 to 48 hours. Each species of nematode harbors a unique species of bacteria, so the rate and mode of killing varies with each symbiotic pair.

The best soil for nematodes is sand or moist, loose loam in full or partial shade. Simply mix the worms with water and apply them to the soil with a watering can or sprayer. It’s best to wait until after sundown so the soft-bodied creatures can dig below the surface before they dehydrate. Applying the worms just before a gentle rain can also help soak them into the ground.

A package of five million nematodes (about $40) can treat up to ten hives. (Where else can you get 1250 items for a penny?) Because nematodes attack many species of insects besides small hive beetles, think carefully before applying them to your soil. Avoid congregations of ground-nesting bees or other beneficial insects if you can.

Commercial insecticides

The EPA has registered only one pesticide for control of small hive beetles inside a bee colony. Coumaphos (an organophosphate) in the form of CheckMite+ is the same miticide labeled for use with varroa mites. The beekeeper can staple strips of the product to corrugated cardboard squares and place the squares on the bottom board of each infected hive. You can find complete directions and restrictions on the EPA Pesticide Product Label available online.

Permethrin products, such as GuardStar, are often deployed as soil drenches beneath colonies in much the same way as salt or diatomaceous earth. Permethrin, a synthetic pyrethroid, is a broad-spectrum insecticide that’s also highly toxic to aquatic organisms, so it should not be used beneath hives where runoff could merge with ponds, creeks, and wetlands.

Because Permethrin is also highly toxic to honey bees, applications should be made in the evening after your bees are in for the night. Near hives, sprinkling cans are safer than sprayers because they minimize the number of misty droplets that can float in the air for long distances and remain suspended for hours.

If you can’t treat it, bury it

Alternatives to treating soil include smothering it with concrete, asphalt, or plastic mulch. But the problem with all soil treatments, including solid surfaces, is their limited area of influence. Adult hive beetles can fly into a new hive from long distances guided by their sense of smell, and beetle larvae can traverse long distances, too. Measurements have shown that larvae can travel for days in search of suitable soil. And if they find it, the offspring can easily fly back to your hive once they reach adulthood.

Although all the soil treatment methods work to some extent, the travel diaries of wayfaring larvae reveal some have spent 48 days and navigated over 220 meters in search of the right soil. And once the beetles reach adulthood, their problems are solved. Adult beetles can fly for miles in search of the delicious scent of a honey bee hive regardless of what’s in the soil below it. (For details on their life cycle, see “The slippery life of the small hive beetle.”)

One alternative to treating the soil beneath the hive is poultry. Some beekeepers keep chickens or other birds fenced within the apiary. Birds have an insatiable appetite for soil-borne insects and do an excellent job of controlling small hive beetles and anything else that lives there.

In-hive mechanical controls

You can buy a panoply of magical mousetraps for small hive beetles, and variations have proliferated almost as fast as the beetles themselves. Most are inexpensive, but their efficacy varies from place to place and hive to hive.

Most of these inventions trap the beetles‌. Many use mineral oil or vegetable oil to drown them once they walk into the trap. The weak point of traps seems to be maintenance. If the traps don’t get emptied and refilled frequently, they will fill up and become useless. I recommend people try an assortment of these traps to see which type works best.

One reliable mechanical control is Swiffer dusting pads or an equivalent product. Beekeepers cut these pads into smaller pieces and place them atop the frames of the uppermost box, just below the lid where beetles like to congregate. The bees dislike these sheets in their hives, so they try to remove them, which shreds the fibers and makes the sheets puffy. Small hive beetles become entangled in the puffiness, unable to free themselves.

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As with the other traps, you must remove and replace these sheets frequently because, once full, they lose their effectiveness. Nearly everyone who recommends Swiffer pads warns against using scented ones. However, two beekeepers I know prefer the scented ones because their bees seem especially eager to remove them from the hive, meaning they get puffy sooner. You could try both and see which works best for you.

The bees’ red-light district

Although not as common as some other controls, red light is a viable management tool for SHB. Since I began providing information on do-it-yourself red-light districts, I’ve heard many enthusiastic success stories.

A beekeeper in east Texas, Joe Caracausa, has been using red light to manage beetles for years. Joe had heard about experiments conducted by Michael Richardson of Superior Hive Solutions. Quite by accident, Richardson discovered that small hive beetles were sensitive to light, especially red light, and they rigorously avoided it. Based on his findings, he designed a hive cover made of red acrylic, called the Beetle Banisher, that emitted only red light into the top of the hive.

Until that time, Joe had been using things like beetle traps and Swiffer pads without much success. So when he read about the red light research, he considered the commercially made red plexiglass telescoping covers for his beehives. The lids were expensive, but knowing he had to act, Joe ordered two.

The red lids came with a clear plastic inner cover with an opaque foil/paper layered on it. “You were supposed to remove three to four inches of the opaque paper from the outside edges of the inner cover, then put the red lid on top of the hive like any other telescoping cover.” The inner cover required support with shims to give the bees enough crawlspace below the inner cover and above the frames. Without appropriate bee space, the bees would likely propolize the inner cover to the top bars of the frames.

“We put them on our two most infested hives and within a week or two, there were no more beetles to be seen. We ordered more lids whenever we had the [money] but never got enough to cover all our hives.”

When the red lids disappeared

Although these lids worked, Joe’s source soon dried up. “I tried to get more but never was able to reach the company. I emailed their website and after about eight months got a reply saying they had abandoned the product. They said they couldn’t sell enough to bring the price down to a reasonable level where people would order them consistently.”

Undeterred, Joe decided to make his own using several plastic telescoping lids that he had on hand. “What I came up with was an estimate that the red window opening would be approximately 12 by 12 inches. So I ordered translucent red plexiglass on Amazon, then cut an 11×11-inch hole in the lids.

“I started using the homemade red lids on some hives where we were seeing high concentrations of beetles. In 2 to 3 weeks [the beetles] pretty much disappeared.” Once Joe ran out of the plastic lids he used a similar design on a wooden lid with an aluminum top cover, a variation that also worked.

After posting Joe’s instructions on my website several years ago, many wrote to say, “Thank you! No more beetles!” Joe says he’s sorry the company that made the original lids is no longer around, but he’s grateful for an idea that really works.

Beetles cause a sea change in hive management

Detailed oversight of small hive beetles requires a major shift away from conventional hive management. To illustrate, I’ve assembled a list of “normal” management activities that don’t work well in beetle territory.

• Flying beetles quickly detect the scent of alarm pheromones, so long inspections can attract beetles from afar. Work fast and efficiently whenever the hive is open.

• Grease patties for controlling tracheal mites may attract small hive beetles instead. Because bees do not patrol the patties regularly, leaving grease patties in a hive long-term can be risky.

• Pollen patties used as a protein supplement also draw beetles.

• Porter bee escapes and triangle escape boards siphon bees out of the supers, leaving beetles free to gorge on unguarded honeycombs.

• Pollen traps contain pollen balls that lure beetles but cannot be patrolled by the bees.

• Because recently swarmed colonies may be too small and weak to control adult beetles, swarm control is paramount.

• Nucleus colonies, too, may have trouble defending against adult beetles. If you use nucs, monitor them closely for pests. The same applies to mating nucs.

• Small hive beetles are attracted to the scent of hive debris, including wax, propolis, and bottom-board scrapings. Instead of leaving these in the bee yard, haul them away for disposal.

• Hives and frames in prime condition without crevices for beetles to hide are best in beetle country.

• Because beetles prefer damp soil, make sure the hives get plenty of sun with only brief periods of shade.

• Honey in removed supers smells wonderful to beetles, so extract or freeze them as soon as possible to protect them.

You must keep up with the pests

People have various results with treatments and control measures. This is true regardless of the pest: Varroa mites, wax moths, tracheal mites, or small hive beetles can be a minor annoyance for some and a major disaster for others.

Staying on schedule is key to successful control, regardless of which system you choose. We are all busy, but if you apply the next treatment a few days late because you procrastinated, worked late, met up with friends, or went shopping, you are giving the pests an advantage over your bees.

Most of these creatures reproduce at a furious pace, so being late makes it difficult or impossible to keep up with them. In addition, allowing a new batch to mature while chemical residues are in the hive favors those with resistance to any system you use.

Time gets away from us, and although we may think we just completed a task, the days have ticked by. No matter what pest you are battling and regardless of the treatment, I suggest scheduling your next steps on a calendar and including a day-in-advance reminder. From observing beekeepers for many years, I believe a rigorous schedule is more important than the specific treatment you choose.

Back in Georgia

Charlene was so repulsed by the slime and filth in her hive that she burned it. The following spring, she re-tooled with new bees and new equipment and is now doing great. She studied everything she could about the beetles and now teaches other beekeepers about their biology and lifestyle.

“It’s a war,” she said. “I watch them, second-guess them, and make plans with multiple strategies. The hardest part is integrating beetle controls with controls for mites and waxworms and wasps. I don’t win every battle, but I’m doing okay. It’s a process.”

Rusty Burlew
Honey Bee Suite

References

1.Cornelissen, B., Neumann, P., & Schweiger, O. (2019). Global warming promotes biological invasion of a honey bee pest. Global Change Biology, 25(11), 3642-3655. https://doi.org/10.1111/gcb.14791

2. Ellis, JD & Hepburn, Randall & Luckman, B & Elzen, PJ. (2004). Effects of soil type, moisture, and density on pupation success of Aethina tumida (Coleoptera: Nitidulidae). Environmental Entomology. 33. 794-798.

3. Shapiro-Ilan, D. I., Gouge, D. H. and Koppenhöfer, A. M.. 2002. “Factors affecting commercial success: case study in cotton, turf, and citrus”, In Gaugler, R. (Ed.), Entomopathogenic nematology, CABI Publishing, New York, pp. 333–355.

About Me

I backed my love of bee science with a bachelor’s degree in Agronomic Crops and a master’s in Environmental Studies. I write extensively about bees, including a current column in American Bee Journal and past columns in Two Million Blossoms and Bee Craft. I’ve endured multiple courses in melittology and made extensive identifications of North American bees for iNaturalist and other organizations. My master beekeeper certificate issued from U Montana. I’m also an English nerd. More here.