Book Lice

The name "book louse" dates back to old Europe, where psocids (pronounced "so-sids") would infest poorly heated libraries, feeding on the wheat paste used for book bindings. 

Until recently, psocids were thought to be just a nuisance. Today, they're considered a food pest because they love infesting grain products.

One reason for concern is that these insects reproduce very quickly under favorable conditions and can develop strong resistance to pesticides in just a few generations. They're tiny, only about 1mm long, wingless, and mostly translucent. Individual insects can live up to six months and lay about 100 eggs in their lifetime.

Psocids frequently feed on processed flour and are strongly attracted to humid conditions that support mildew. It doesn't take much extra moisture to support mildew, even in a modern home. Poor ventilation or not using exhaust fans when cooking and bathing can enhance these conditions. Add a little heat, and it takes just a few weeks for them to overrun the pantry.

Kitchens, laundry rooms, and bathrooms are common places for infestations, but if conditions are right, they can infest mulch outside and invade other rooms by moving through exterior walls. 

The best defense against psocids is prevention.

To avoid infestations in the kitchen, don't buy more processed grains than you can consume in a couple of months. Keep all processed grains in sealed containers away from heat (our ancestors called it cool, dry storage). Always use exhaust fans when cooking or running the dishwasher (all that steam has to go somewhere).

If you do get an infestation in the kitchen, don't panic. Throw away any infested materials. Sealed packages can be put in the freezer overnight to kill any psocids or eggs on the packaging. Wash the cabinet with soapy water and let it dry thoroughly. 

Try to figure out what caused the infestation. Remember, they need heat and humidity. Take away either of these and they can't proliferate.

For infestations elsewhere in the home, it's almost always moisture causing the problem, usually due to inadequate ventilation. 

Check if the exhaust fan works. Is it clogged, or too small? 

Did you cover your foundation vents last winter? 

Did you remember to uncover them before April? 

Is the vapor barrier under your home in good repair? If not, one square yard of exposed soil can release two quarts of water vapor a day.

Lastly, are you using bark mulch in the planting beds near your home's foundation? This material supports the mildew these insects evolved to consume. If populations get high, they can invade the house from outside.

If you can't determine the source of the infestation or if it persists, give us a call.