For Release October 22, 2002

Annoying Autumnal Invading Insects

by Chuck Otte, Geary County Extension Agent

As the air begins to crispen and the leaves change colors and drop to the ground, we will invariably be treated to yet another round of annoying insects that are trying to gain entrance into our homes. While few of these pose a true threat, they can all be quite annoying. While there are a lot of critters trying to get into your house this fall, like crickets, spiders, boxelder bugs and rodents, Iím going to concentrate on two that seem to annoy many homeowners.

Both of these insects are usually referred to by homeowners as gnats. One truly is a gnat (fly) the other is not. One originates in the house and stays there to the annoyment of the residents, the other originates outside the home, but tries to get in, again to the annoyment of the residents.

There is a group of small flies, gnats, that are known as drain flies, fungus gnats or humpbacked flies. This group of insects has very diverse food requirements. Some will feed on decaying organic matter in house plants. Others will feed on the fungi feeding on the organic matter in the soil of houseplants. Still others will develop on the fungi feeding on the gunk that exists in the drains of our homes. These small flies are often overlooked, until they start flying about your head or landing in your morning juice. Since the gnats may be originating in your drains, they are often localized in bathrooms or kitchens.

Do not start dumping pesticides down your drains. Not only is this ineffective, it is technically illegal and very ill advised. Regular cleaning of your drains will help reduce the fungi that the gnats are developing on. It may take several treatments over several weeks or months to knock the problem down, but it does help. If you have brought in a lot of houseplants, you may need to apply an insecticidal drench to the potting soil to reduce the problem there. And hanging a no pest strip will help knock down the adults. These gnats can appear all winter long, so you might as well get to work on them now!

The other gnat like critter is called the hackberry psyllid or hackberry nipplegall maker. This small gnat like creature is closely related to the cicadas, whiteflies and treehoppers. As a larvae, this is the insect that is responsible for the hard little bumps on hackberry tree leaves. All during the summer, this insect, as an immature, is safe inside those little bumps feeding on the sap of the tree. But in the fall, the adults emerge, by the thousands, and are attracted to houses often massing on the screens and windows by the thousands.

While annoying, all the psyllids are trying to do is find a place to hibernate. But they can make it very difficult to enter the house without a few dozen coming along. You can spray areas where they congregate with a general garden insecticide, but be sure to wait until the time of day when there are a lot of them, because you need to spray them directly for optimal control. The hackberry psyllid problem usually lasts just a few weeks until all the adults emerge and find a place to hibernate or die from cold weather.

While both of these pests are annoying, it may be somewhat reassuring to know that they arenít life threatening or destructive. Remember that making sure your house is well sealed is always the first step in reducing invading insect problems, and that insecticides should be considered a secondary approach and then only after reading and following all the directions on the insecticide label!


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