Beetles

BEETLES

I keep finding drugstore beetles in the light traps placed high above the floor in a food processing plant. The plant makes dried treats for pets. Can you explain this beetle and can you think of a source?
The Drugstore beetle, Stegobium paniceum (Linnaeus), most likely was named as such because it was commonly found infesting early pharmacies where dried herbs and other plants were used to compound medicines. Today, it is considered a stored product pest and, as you have noted, it can get into many areas since the adult does fly. You will find it in lights for two reasons. One possibility is that it was attracted to overhead lights or the light in the trap. The second reason is that the insect light trap tray might have a food source such as ingredient dust. These insects don’t feed on insects in the tray as readily as dermestids such as the warehouse beetle, but the tray can be attractive.

As far as sources, don’t expect that the beetles are infesting just the areas near the ceiling. In fact, that is probably not the case. Look for raw ingredient storage and seek out dried ingredients. Also, look for product spills and even food dust on the overhead areas. Don’t rule out minor ingredients such as spices. You can zoom in on an area by installing monitoring devices including pheromone traps. Then removal of the source can be done; if there is infestation on the outside of packaging but not inside, you can heat the material to at least 140° F for several hours. Don’t forget that animal food facilities must be maintained in the same fashion as plants that make human food, so any infestation must be addressed quickly.

I keep finding carpet adult carpet beetles near the windows at my client’s home.  She has no carpets in the house, mostly hardwood and tile floors throughout their home with area rugs in some rooms, but I can’t find any signs of damage.  Where they coming from and what are are they feeding on?

With the advent of synthetic carpet fibers, carpet beetles are rarely found feeding on carpets in modern homes.  The preferred food sources for carpet beetles are natural animal fibers like wool.  When carpet beetles earned their common name, many rugs and carpets were woven from wool, where the beetles were often found feeding on and damaging the fibers.  With the exception of antique or specialty rugs, natural animal fibers are rarely encountered today.

Carpet beetles, which are members of the family Dermestidae, will feed on other animal products in structures, which is probably what’s going on in your case.  Check the property for hunting trophies or animal hides, which may harbor an infestation.  In pet supply stores, natural dog bones are often infested, so carefully inspect any treats that you bring home for your pets. Along those same lines, pet hair can also be a good food source carpet beetles.  If your customer has pets, recommend that they perform a deep cleaning of the any areas where pet hair might have accumulated, like in the cracks and crevices around floor vents or baseboards.  Finally, if the structure has a history of infestation by overwintering pests like, multi-colored Asian lady beetles, brown marmorated stink bugs, cluster flies or other pests, carpet beetles may be feeding on dead insects in the wall voids.  It turns out that dead insects are a favorite food for carpet beetles, in fact, entomologists take care to keep them out of preserved insect collections where they can be extremely destructive.

I have a potential customer with a solid oak living room floor and it appears to have a powderpost beetle infestation. How can I tell if it is active and can I perform a topical treatment or do I have to ask them to strip the flooring?

It sounds like the floor has an infestation of Lyctid or Anobiid powderpost beetles. Lyctines prefer hardwoods while Anobiids will infest hardwoods or soft woods. The emergence holes look similar and if the frass and hole walls are light colored, that usually means that the wood particles have not oxidized into a darker color and thus would be considered fresh or active. You rarely see the actual insect. Pay careful attention, for if the holes appear to have any cross sections of galleries, that means that the damage was done by an insect prior to milling and then is not a concern. Some states do require determining if the infestation is active if this is a real estate transaction. If there is question or hesitance on the part of the homeowner, you can photo or mark the holes and return later in the season to see if there are new holes.

If you do decide to treat, most insecticides must penetrate the wood so the polyurethane must be removed for optimal effectiveness. Check the label and manufacturer’s information for more information on how to use specific products.