The Homeowners Column

The Homeowners Column

Nuisance Insects That Make Their Way Indoors in the Fall Are Now Trying to Get Back Out

Photo of Sandra Mason

Sandra Mason
Extension Educator, Horticulture
slmason@illinois.edu

I wrote an article recently about the benefits of ladybugs. In the garden, ladybugs eat lots of bad bugs including aphids and scale. I promptly got a note from a gentleman who begged to disagree with me. He had buckets of ladybugs inside his home and found them far from useful except as an exercise in futility. Somehow ladybugs quickly lose their glamour when they saunter across the kitchen counter. Even though ladybugs are beneficial, they have some habits we may not appreciate.

This time of year all the critters that made their way into your home last fall are now trying to find their way back outside. Elm leaf beetles and boxelder bugs are common winter residents indoors. Over the past couple of years a different critter has found our homes particularly appealing. You may be noticing the Asian multicolored lady beetle inside your home right now. The Asian lady beetles are one fourth inch long and are the VW bug dome shape. They usually have orange wingcovers with 19 black spots. No need to count the spots. Their multicolored name comes from the variety of color possibilities ranging from tan to red and the spots may be very small to absent, to large and obvious.

In their native areas in Japan the ladybugs spend the winter in cracks and crevices of cliffs. Cliffs are tough to find in central Illinois so what is the next best upright thing around–our homes of course. In the fall they enter through cracks and crevices usually around windows or they may fly through doors as people go in and out. Other types of ladybugs may have been brought indoors in houseplants that have spent the summer outdoors. Particularly on warm sunny days in the fall insects may be seen crawling or flying around windows. In the spring they attempt to return to the outside to lay eggs.

Remember ladybugs are actually good bugs outside. Repeat this over and over to yourself as you are scooping them up from your windowsills. Both the young larva and the adults feed on a wide range of soft bodied and slow moving insects such as aphids and young caterpillars. According to Phil Nixon, U of I entomologist, they also feed heavily on soft scale insects which is why they were imported into this county from Japan. The larvae are quite science fiction looking. They look like tiny black alligators with an orange stripe. In the aphid-size world they probably seem just as fierce.

The good news is elm leaf beetles, boxelder bugs and lady bugs don't reproduce or feed while they are indoors, but are a nuisance with their presence. Often ladybeetles wander around for awhile and die indoors. Controlling these insects indoors consists of vacuuming or your best scoop and toss outside method. Soon they will all have gone outside.

According to Phil Nixon, insecticide sprays are likely to have little effect on hard-shelled insects that are not feeding. Caulking cracks and crevices around windows, along the foundation and around doors will help reduce the numbers that can make their way indoors in the fall.

Our perceptions certainly color our ideas of the usefulness of wildlife. It reminds me of a conversation I had with one gentleman who said snakes around here were harmful. I quickly pointed out to him we have no poisonous snakes in our area except for the very rare massasauga rattlesnake. He explained that snakes were indeed harmful since he had a heart attack every time he saw one. One person's parsley worm is devouring their favorite herb while the same insect is another person's swallowtail caterpillar awaiting to emerge as a beautiful butterfly.

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