Fixit: Fungus gnats are the culprits

A little Minnesota mystery has been solved.

A woman wrote recently to say she was being driven buggy by nearly invisible flying insects that came out of nowhere and wouldn't leave her alone. They got in her face, up her nose; they followed her into the bathroom and into bed.

I didn't have a name for her tormenters. Neither did my sources.

But readers did.

"They're fungus gnats," they cried in unison by mail, phone and e-mail.

They spoke from experience and provided some remedies, too.

Several readers blamed potted plants, especially any brought in from outdoors late last fall.

Don't overwater the plants, she added.

Marsha Tollefson of Longmont, Colo., suggested cutting a potato and putting it on the soil of a plant to attract the bugs.

"She can toss it after a day or so, and the bugs go with it," Tollefson explained.

Fungus gnats are water lovers, which explains why they might be found in a bathroom or buzz around moist nasal passages, but it's also a means for their demise, readers said. They suggested putting out small containers of liquid to attract the tiny flies, which then fall in and drown.

A few readers said you can stop the speeding pests midair and thereby examine them.

Examining them is a good idea. Not every tiny flying insect you see in the house is a fungus gnat. They could be:

• Fruit flies, which can be found near overripe fruits and vegetables, beverage bottles that are being saved for recycling and trash bins.

• Moth flies, which typically can be found in the gelatinous film in drains and sinks, or associated with sewers and sewage from sewer breaks.

• Phorid flies, which are commonly found in bathroom drains, food residue in trash containers, rotting food, dirty mops and dish rags, and sewage from broken sewer lines.

The solution to any of these flies is to identify them, locate where they are coming from and remove their food source.

Finding the source of the infestation can be challenging and often involves some detective work, he said. There are many instances of odd and unexpected sources that these flies have infested.

Despite how difficult it can be to find the food source, don't be tempted to use insecticide sprays. They won't work, Hahn said.

Get rid of the food source, and you'll be rid of the flies.