Entomology (Study of Bugs)/bathroom bugs
I have a new straw-bale house just outside of Trinidad, Colorado. Front range - 7000 feet altitude. In one of the bathrooms, I have these tiny, light brown bugs. I pick up literally hundreds daily. They are only on the counter. They seem to like the grout. The countertop was made from some old marble tiles, with grout in the joints and around the sides. I have sealed the entire countertop with sealer. It's a clean bathroom. We've stopped taking showers in that bathroom thinking maybe the humidity, but that hasn't helped after 5 days. I put containers of desiccant down. Not to mention alcohol spray, vinegar, soap and water, ant; spider & cockroach spray. What finally seems to kill them is permethrin spray that I spray nightly. But I'm still picking up hundreds per day. Mostly dead. And I've been spraying nightly for the past 10 days.
This has been going on for 1-1/2 months.
An acquaintance who is an exterminator said they are not psocids, but he doesn't know what they are. And even if they are psocids, how do I get rid of them? While building the house, we used a moisture meter for every single straw bale. Not one had over 14% moisture. Over the bales is concrete, sealer, then paint. We live in a dry climate. We're not taking showers in that bathroom anymore and we've put desiccant down. I'm at wit's end. I've picked up thousands of their nasty little corpses.
Those are psocids (booklice). These insects are always associated with dampness/moisture but it only takes a little to support the mold that these insects need. My guess is the straw has enough moisture (and organic material) to support the mold and psocids. In your climate I think the straw will eventually dry out enough so that it no longer supports mold but that could take awhile. Fortunately the psocids are harmless and can be swept up until then. Be sure to caulk any cracks to seal the walls. floor and ceiling. There's also a number of dust insecticides that will work and are not very toxid, see http://www.livingwithbugs.com/use_dust.html