Identify, get rid of those little flying insects

By Stephanie Hughes

OSU Ext. master gardener volunteer

I have a problem in my home – little flying insects that want to buzz around my face, crawl on my arms, and just be a nuisance. So I set out to identify the culprits and how to get rid of them.

I finally caught one in my bathroom and brought it in for identification. After close inspection under the microscope, I surmised it was a fruit fly. The characteristic red eyes and wing formation proved this. But I still had another type that wanted to be around me, attracted to the light from my Kindle. I got a couple of these, and with the same research I deduced these to be fungus gnats (Orfelia sp.). They can be introduced into the home from potted plants and flower boxes where they love to dine on humus-enriched soil, causing plants to be damaged and lose vigor. Root damage symptoms can include wilting, poor growth, yellowing, loss of foliage. It is these symptoms that indicate larvae feeding on living plant tissue, especially the root hairs — the plant’s uptake system for water and nutrients.

Gnats reproduce in moist, shaded areas on decaying matter (usually dead or dying leaves). The life cycle is about four weeks, with continuous reproduction in homes and greenhouses, where it is constantly warm. Adults live 7-10 days, depositing eggs, as females lay up to 100-300 eggs in 2-3 batches each. Eggs are all of the same gender, hatch in 4-6 days, and larvae begin to feed for 12-14 days. They pupate for 5-6 days, with generations overlapping. Prevention begins with examination of your plants for signs of infestation. Overwatering, water leaks and poor drainage cause activity. Allowing the plant medium to dry, without injuring the plants, is effective in killing maggots. Remove old plant material and debris. Practice good sanitation, using fly traps to attract and kill adults. You can also use potato slices to catch them. Use yellow sticky cards (traps) to detect gnats. Blow gently over your plants and see if a cloud or a few gnats take off – a sure sign.

Integrated pest management (IPM) should be used when controlling insects. There are organic options as well as sprays or aerosols labeled for “gnats” or “flying insects.” Always read and follow directions and instructions. House plants summered outdoors can become infected, and gnats are brought inside to infest the home over the winter.

To read more about these little bugs, go to:

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