Minute Problems (AKA: Munching on molds)

If you’ve recently opened a newly constructed building or moved into a brand-new home, you might have noticed some tiny, dark specks crawling near the baseboards. Before you call the movers or file a massive insurance claim, let's talk about the beetles in the family Latridiidae, commonly known as plaster beetles or minute brown scavenger beetles.

These beetles are the ultimate "I’m here because it’s damp" indicators. In fact, they have a history that goes back to the days when walls were made of actual plaster—hence the name. Like many of our stored product beetles, these will develop in about 30 days. They are that typical redish brown color and are about half the size of a flour beetle.

I often get frantic calls saying, "Chelle, the building is brand new! How can I have bugs already?" The answer is in the construction process itself. During building, the "envelope" is open. Rain gets on the wood studs, and concrete holds moisture as it cures. Once the building is sealed and the HVAC kicks on, that trapped moisture migrates out, growing microscopic layers of mold—the absolute favorite food of the plaster beetle.

In the food industry, plaster beetles are more than just a nuisance; they are a major audit risk. If I’m in a food processing plant and see these beetles, my "troubleshooter" brain goes into overdrive. There is moisture somewhere, moldy product, leaks, or something going on that is creating the conditions for these to thrive. And since these are small, they can get into lots of hidden and hard to reach areas.

They don't eat the flour or grain, they feast on the fungus growing there. Also, they are small enough to get into packaging. To an auditor, an insect is an insect, and a "minute brown beetle" in a finished product looks just as bad as a cockroach or fly. Sometimes they arrive at your facility on "green" wooden pallets that are still holding moisture. If you bring those into a humid warehouse, you’ve just invited a population explosion.

Chelle’s Soapbox: My biggest pet peeve with plaster beetles is the "spray first, ask questions later" approach. It doesn't work. Why? Because as long as the moisture is there, more beetles will find the mold. You aren't "solving" the pest problem; you’re prolonging it and probably not even killing many adults.

For homeowners out there, don't panic. They aren't bed bugs, and they don't bite. In a new house, these beetles are usually "temporary roommates." As the wood and drywall finish drying out over the first year or two, the mold disappears and the beetles starve. However, if you see them in an older structure, they are your early warning system for a leak. Check your windowsills, under the bathroom sink, or behind the washing machine. They are essentially a "Check Engine" light for your plumbing. Even drying out the environment a little with fans or dehumidifiers can really reduce the populations of these beetles.

The Bottom Line: Plaster beetles are telling you a story about your facility's environment. If you listen to what they’re saying about the moisture, the puzzle gets a lot easier to solve. If you have a pest puzzle that's been puzzling you, let us help!