This summer I have been noticing these itsy bitsy little grey bugs on my window sills in the kitchen and bathroom. They are so light and tiny I have almost thought they were dust at times. Last week I diluted some bleach on a cloth and wiped down the sills. That seems to have helped. I’d still like to know what are they? How can I stop them? Will I need to see the wizard or can you help?
Bugged in the Boondocks
First of all I want to thank you for the evening I spent with phantom crawlies after wandering down the rabbit trail of mite and lice research. Blech. Second to calm down any entomologists -no, spellcheck I most certainly did not mean etymologist- out there, the term “bug” for zoologists and pedants applies only to the order hemiptera. I know you probably don’t care, I’m just preventing an email or two.
Since you noted that these were light in color and didn’t mention any jumping, my bet is they are booklice or a close relation. Booklice (book lice) are not true lice and are also called psocids. These little bugs feed on mold and fungi and require a humid environment. They tend to hang out in windows as well as in the books that give them their name. Since they feed on molds reducing the humidity that encourages mold growth is the simplest way to control these tiny harmless pests. Your wiping the sills with dilute bleach probably killed their food source and your problem may be solved.
They are harmless so try not to stress too much about it. They aren’t causing any damage and they fall into that category of creature that we just try to not think about too much. They aren’t destroying property (except in the most severe infestations), triggering allergies like dust mites, or biting like bed bugs. They are mostly just a barely visible nuisance.
I do want to note that occasionally booklice can find their way into pantries where they can infest grains. In that case, you toss the infested grains, air out the pantry and store grains in an airtight container.
Other possibilities for tiny creepy crawlies in window sills.
If you squash these mites and they leave a reddish stain, they are most likely clover mites a common, harmless but aggravating critter that tends to invade windows. To prevent stains on your woodwork, simply vacuum these and call it good. Just don’t forget to empty the vacuum or you end up with mites in other places as they can usually crawl back out. Clover mites aren’t going to damage anything, they are just wandering around in search of food.
Finally the last usual suspect would be springtails. These little, jumping arthropods feed on decaying leaf litter. If you use mulch near your house they could be wandering around looking for more food. These things are also harmless but can be a major annoyance if they move into your house. If you notice they congregate in a window be sure to check for water damage as they are attracted to organic decay.
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