Tiny bugs on roof tiles

Asked May 10, 2015, 11:21 PM EDT

I was checking the roof tiles for cracks and saw a ton of these tiny bugs running around, maybe 1mm or max 2mm in length. It's a 2-story home with composite/concrete tiles.

Does anyone know what they are and if I need to do something about them?

Thank you!

Contra Costa County California

3 Responses

To whom it may concern,

These images are of insects in the large order Psocodea, or chewing lice. They may be barklice, feeding on molds and lichen on the roof tiles, but, perhaps just as likely, they are bird lice, feeding on dander and feathers of a bird colony. Do you have nests of swallows, swifts, sparrows, or some other bird species on / in this structure? If so, then removal of the nests will be the proper management of these insects. Most birds are protected during nesting season, so you may have to wait until the fall to remove nests and take preventive measures to exclude the birds from nesting next year. You can submit specimens of your insects to your county's UCCE Master Gardener program for positive ID: http://ccmg.ucanr.edu/Ask_Us/

You can also try to ID these critters yourself, though it may be hard within this particular order: http://bugguide.net/node/view/67



I hope this info helps. Best,


Thank you Andrew for the reply. We have no birds on our house but the tiles do have a good amount of lichen growing.

Do you know if they present a risk to the house, and what is the best way to get rid of them? I'm sure we can work on treating the lichen, but should we spray the roof tiles with anything for the bugs?

Thank you!

It sounds as if these are barklice then, based on the absence of birds and the presence of lichen. They do not damage structures and are not usually managed as pests. There is no need to do anything about these insects, but abundant lichen may indicate excess moisture on / in the structure. This is also likely a seasonal phenomenon since dry and hot weather (on its way) will knock back the lichen growth and cause a population crash of the barklice. For more info: http://extension.usu.edu/files/publications/factsheet/booklice.pdf