Both wax moths and small hive beetles are considered secondary pests of a hive. Strong, queenright hives are generally able to control these pests on their own. There are management steps that the beekeeper can take to help the bees in their task.
Wax moths enter the hive to lay their eggs. They lay them in small nooks that the bees cannot reach. The eggs hatch into larvae that can reach up to an inch in length. They are fat, cream colored larvae with pointed ends and a brown head. The larvae spend the next stage of their live chewing through and destroying drawn comb. When the reach the pupa stage, they begin to draw massive amounts of sticky web that can cover entire frames.
Prevention is the key to controlling wax moths. Don’t give a hive more drawn comb than they can patrol and protect. If you find an infested frame, remove it from the hive and freeze it for two days before returning it for the bees to clean up. If you can’t freeze it, you have a few other options. Set it in a strong hive for the bees to take care of the problem for you. Expose the frames to strong sunlight, which drives the moths away. Spray with Bacillius thuringiensis (Bt), a natural product that is non toxic to bees, honey, and humans.
After harvesting your honey supers, place them back on strong hives, freeze, or store them in a cold, well lit area. Bt can be sprayed onto drawn comb before sealing it in plastic for storage. You can purchase Bt online or in garden centers.
ParaDichlorobenzene (PDB) is also approved for treating empty honey supers for wax moths. It is a suspected carcinogen though, and has been shown to be present in honey in small concentrations. (For more information on PDB, check out the NPIC Fact Sheet for PDB.) That doesn’t fit with our management style at Russell Honey, so this is not a product I choose to use. Commercially produced mothballs are generally made of naphthalene, which is not approved for contact with food surfaces.
Small Hive Beetles
It is a sick feeling to pull a frame out of a hive and see that it has been slimed by the small hive beetle (SHB). Just like the wax moth, the SHB is a secondary pest that will exploit weakness and take over a struggling hive. In my case, I lost several frames because I made a nuc with too much drawn comb, too few bees, and an excess of pollen patty. These three mistakes cost me a frame of honey, but I did catch it in time to save the hive.
SHBs are not as much of a pest in the northern US as compared to the south. It seems winter is on our side in helping keep the SHB population under control. A strong hive is your best defense, along with a few preventative measures. Kill any beetle you see by squishing it with your hive tool. The bees are unable to kill the adult SHB, so they corner them and hold them hostage. When you disturb the hive for inspections, you may see suddenly free beetles scurrying about. Squish as many as you can!
Give hives only as much space as they can defend. If you run a screened bottom board, a pan of oil placed under the hive will kill SHB larvae as they drop to the ground to pupate. Diatomaceous earth sprinkled under and around the hive will kill SHB in all life stages. It also kills bees, so don’t place it directly in the hive.
Place hives in full sun for lower SHB populations. The ground may be drier in a sunny location and less conducive to the pupa life stage. Pollen in pollen traps and supplements, as well as the protein in pollen substitutes, is a food source and breeding ground for the SHB. Feed colonies small amounts of patty only when they need it and clean pollen traps frequently.
Beetle traps are a more time intensive management strategy. They can be as simple as a piece of card stock taped to the underside of the hive lid. The bees will trap the beetles beneath the paper, and you know just where to start squishing during your inspection. You can also purchase pre-made beetle traps in a variety of styles. They all basically work the same way, by providing a dark place for beetles to run and hide. Once inside they are trapped in oil and drown. Some traps are disposable, others will need cleaned out and the oil refilled periodically. Most beekeeping supply companies carry beetle traps.
Adding nematodes to the soil under your hive may help. It is unclear if the nematodes are able to survive in all soil types and conditions, and adding them is just one step in a pest management strategy.
Unattended honey supers are choice targets for infestations of wax moths and SHBs. Supers above bee escapes or waiting for their turn in the extractor have no bees to defend the honey against these pests. Supers should have their honey processed out of the comb and be properly stored as soon as possible, definitely within 3 days. If you can’t complete harvest in 3 days, leave the supers on the bees until you are ready to process them.