Archive for Wednesday, October 25, 2000

Boxelder bugs moving in

October 25, 2000

With the rains and sudden cooling of the temperature, boxelder bugs have begun to move into sheltered areas to overwinter. And the calls have started to come into the extension office about how to control these pesky insects.

These insects become household pests as they crowd into any cracks and crevices they can find. They often move toward structures, entering near the foundation and pushing into cracks. Eventually, some of them may make their way into wall voids where they can spend the winter with you in your nice warm house.

Boxelder bugs will not bite humans or damage buildings, furnishings, clothing or food. They can spot curtains and walls, and they may leave a stain if crushed. Boxelder bugs are mainly a nuisance pest because of their presence when crawling and flying about the house and accumulating in light fixtures.

In case you are not familiar with them, boxelder bugs are about one-half inch long and dark brown to black in color with red lines on their backs. Young ones, or nymphs, are wingless but generally similar in shape to the adults. Smaller nymphs are solid bright red, but as they get older, they will have some black markings.

In October and November, boxelder bugs will crawl under shingles and into cracks and crevices to gain access to inner wall spaces where they will hibernate during the winter. On warm days during winter and early spring, the bugs will become active and appear on the warm sunny outside of the house, or they may appear on the inside of the house.

Boxelder bugs are more common during dry summers, which explains why we are seeing so many more of them this year. Wet weather is a problem for the bugs as the small nymphs are easily drowned.

The insects breed during the summer. You don`t have to have boxelder trees to have boxelder bugs. Golden rain trees are also host trees and some maples (which are closely related to boxelder trees) also seem to attract boxelder bugs.

This is the time of year when the bugs congregate in clumps or masses on tree trunks or the sides of nearby buildings. To rid your home of them:

Insect-proof the house. Prevent points of entry. Caulk cracks and crevices, screen vents and everywhere the insects can get in.

Check your yard for clutter. Lumber, stored firewood and similar materials can serve as a source of overwinter shelter.

You may be able to pour or spray them with hot water (165 to 185 degrees Fahrenheit). Those you can reach with hot water can be quickly killed.

Insecticide sprays can be used, but don`t expect much help from any residual of the sprays. Insecticides sprayed directly on the insects will usually kill them, but not instantly. It will take some time for the spray to work. Direct the spray to hit the bugs as directly as possible. Don`t expect bugs crawling over the treated surfaces a day or two later to be killed.

-- By Sy Nyhart, county extension agent for agriculture.

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