The small hive beetle (SHB)-another opportunist
Some number of SHBs can be found in nearly every state in the union. If SHBs aren't already in your apiary, they probably will be, soon. Here in northern Michigan, we've been seeing some adult beetles in our hives since 2010. Prior to these sightings we were confident that we didn't have to deal with them, but they are here.
The SHB is viewed as anything from a minor annoyance to a pest that will wipe out your apiary in no time flat, depending on who you talk to. Since the adult beetles that we have found in our hives have only been in very small numbers and have only been found directly under the mosquito netting beneath the quilts, I tend to believe that they are going to be, typically, much like the wax moth. That is to say that I and many others believe that strong hives are likely to keep SHBs in check on their own, especially in areas where beetles are not very prevalent. States which seem to have the biggest problems with SHBs include GA, TN, FL, NC, SC and AL. In these areas, the SHB may be more difficult to control, and intervention by the beekeeper may be needed.
Adult beetles are dark brown to black and about 1/4" in length. They have clubbed antennae, although their heads, as well as their legs, are often recessed and not visible. Adult beetles may be present in the hive without being cause for alarm. Adults need to be able to move somewhat freely in the hive in order to find a suitable place to lay their eggs. Strong hives will often chase the beetles into hiding or even use propolis to imprison them so that they cannot carry out their mission. Even small amounts of successfully hatched larvae may not pose a significant threat since they are likely to be ejected from the hive by the bees. The real problems occur when weak colonies allow large numbers of larvae to hatch out in the hive. The SHB larvae tunnel through the combs, consuming honey, pollen and even brood. They defecate in the honey and cause it to ferment, ruining the honey and making a slimy mess out of the combs. The bees will then abandon heavily infested combs or even abscond from the hive completely if the beetle population is not brought under control quickly.
Our top-bar hives are more resistant to SHBs than are framed hives or Kenya top-bar hives. This is because they offer very few places for beetles to hide, especially if they are opened very infrequently by the beekeeper since any crevices where beetles may find shelter will quickly be filled with propolis. When frames are used in any hive, the number of SHB hiding places increases at least ten-fold. Even worse, when framed hives are inspected frequently or manipulated by the beekeeper, this makes the probability of an SHB infestation even greater. Breaking propolis seals and moving hive parts around often creates hiding places and/or releases beetles that have been imprisoned by the bees! KTBHs are likely the best environment for SHB to thrive, as the beetles can usually hide, breed and lays eggs between the top bars and the roof assembly. We have heard of entire apiaries of KTBHs being wiped out by beetles in no time flat because the beetles were able to do this.
All of our hives offer screened floor assemblies as a line of defense against the SHB. Many people know that screened bottoms are used for the monitoring and reduction of varroa mites, but what some may not know is that SHBs do not like light. Therefore, a very common area for beetles to get a foothold (the solid bottom board) is eliminated. When beetles are forced up into the hive to escape from the light, they are forced to live in much closer proximity to the bees. This allows the policing of hive beetles by the bees to be much more effective, greatly reducing the possibility of an infestation of larvae.
The beetle larvae must pupate to become beetles. They do this by leaving the hive and boring into the soil below or very near it. Once there, each larva spins a cocoon and emerges later as an adult beetle to re-enter the hive. If a liberal amount of hydrated lime diatomaceous earth is sprinkled on the ground under and around the hive (6 foot radius), the exoskeletons of the beetle larvae will be damaged as soon as they come into contact with it. The larvae will then dry out and die before successfully pupating. Use this instead of Guard Star, a commonly used chemical pesticide. Guard Star can be harmful to your bees and often doesn't work, since it is a petroleum based product that the beetle larvae can detect. Oftentimes, they simply pupate far enough away from the hive that they escape its effects. Also, for those of you who feel the need, either because you are planning to use a framed hive or because you live in one of those areas where SHB populations are well established, we have developed a means of installing SHB traps in the upper hive bodies of our hives. The first thing that you need is the Better Beetle Blaster, a disposable SHB trap that can be reused if desired. This trap cannot be installed if the quilt and mosquito netting is laying directly on the top bars (as it is normally), so the second thing that you need is a shim. The 1/2 inch space is absolutely needed if you are going to do this! The bees must also be able to enter the trap area so they can police what is going on up there! This combination should easily keep beetle populations under control and the traps will be very easy for you to install, monitor and replace (or empty and reuse), without creating the need for your excessive intrusion into the hive. Our friend John Seaborn (Wolf Creek Apiaries) has discovered that these SHB traps are easily reusable if hydrated lime is used in them rather than mineral oil, since the hydrated lime powder and dead beetles are quite easily shaken out, after which fresh lime can be added and the trap reinstalled in the hive. It's important to not overfill the traps with lime; only fill them to about 1/3 full. Otherwise, the beetles may be able to climb out of them. When installing Better Beetle Blasters in your hive, they should be installed in the upper hive body, between the two outer top bars on either side. Thumb tacks can be used to secure the trap in place, keeping it pressed down firmly against the top bars. Two traps can be installed if needed, one on each side of the box. The shim is then placed over the hive body, with the screened side up, before reinstalling the quilt and roof. Hydrated lime can be purchased at most any farm store and can be used outside the hive as well when combating SHBs.