Ever Wondered Why Your Windowsill Is Suddenly Covered With Black Bugs?

Our Texas insect expert answers common questions about bugs.

By Laura RiceOctober 16, 2017 9:30 am,

Have you ever been shocked by the sight of hundreds of black insects on your windowsill? Wizzie Brown, an insect specialist with the Texas A&M Agrilife Extension Office says these infestations are not a plague, or even particularly dangerous.

On what the bugs actually are:

Usually the call I get is ‘I have black gnats by the thousands, and I don’t know what to do with them.’ And it’s actually hackberry psyllids. They are an insect that feeds on hackberry trees.

On how to identify hackberry psyllids:

They will come to the house, usually around door and window areas. And they can crawl through screening, especially if you have any little holes in your screen. And they usually collect on the windowsill inside the house. And people get freaked out because there’s hundred of insects that weren’t there the previous day.

On whether psyllids are dangerous:

They can bite, because they do have a piercing, sucking mouth part. And if you’re sensitive, you may feel it. But most people just get creeped out by all the insects that show up magically overnight. Like a gift, Only the bad kind.

On how to deal with the bugs:

There’s not a whole lot you can necessarily do about them, short of cutting down all the hackberry trees. You can try putting smaller screening on your windows, and then putting some sort of pesticide treatment around your windows and doors to keep them outside.