What is this insect?

Asked June 5, 2018, 11:05 AM EDT

I seem to have a very sudden infestation of these insects in my house. A couple days ago I saw one in the kitchen and then yesterday there were several dozen swarming around. I'm not sure what they are or what's attracted them inside (and therefore I'm not sure how to combat them!). They are about a half inch long, they fly, and are very attracted to light. My house is in Portland in a pretty densely populated neighborhood. Any insight? Thank you!

Multnomah County Oregon

2 Responses

The insect is a fly. At this time, there’s little I can suggest other than it won’t be a problem for people, pets, or structures. As you’ve noticed, they’re attracted to light. The only thing you may need to do is to open one window and allow them to leave.

They appear to be fungus gnats. Such flies often breed in very moist to wet sites. So, you get to be the detective: After you locate the source, then dry it out. Running a fan for several consecutive days helps. Possibilities are numerous, among them a leaky roof, a rotting window frame or other wood object; a forgotten wet mop that never dried completely; and even leaking plumbing.

“Fungus Gnats” may provide some ideas where to investigate- http://ipm.ucanr.edu/PMG/PESTNOTES/pn7448.html.

Thank you very much! That is very helpful.