Imagine fighting tons of small bugs every fall without exception, only the bugs are in the house, not out. This is the annual scenario of boxelder bugs who live off boxelder maple trees spring and summer, then do their darndest to get into your home to spend the winter. Wherever you find boxelder maple trees, you will find nuisance boxelder bugs.

Boxelder maple trees, also known as ashleaf maples, aren’t desirable trees in the first place. For whatever reason, the trees were initially planted as shade trees because of their rapid growth. In some cases, the tree grew to 40-50 feet tall, but more often than not it performed as a shrub of 10 to 15 feet tall. The foliage doesn’t resemble those of maple trees; foliage usually is comprised of coarsely toothed leaves, sometimes three to a cluster, but often five.

Boxelder maple is vulnerable to wind and storm damage. Young trees generally display green bark whereas mature trees are unattractive for its gray-brown bark and tree trunks that are often cracked. Snowstorms play havoc with the trees.

As for boxelder bugs, people climb the walls every autumn trying to defend their homes against the bugs. During spring and summer, bugs feed on boxelder blossoms, also tender twigs on the tree. Every fall, they fly to the nearest home away from the tree where they climb the exterior wall of the house in an effort to overwinter indoors. The sight of finding hundreds, maybe thousands, of boxelder bugs climbing the wall of the house is enough to make people want to move.

How you deal with boxelder bugs isn’t as difficult as it seems. In late spring when boxelder maples begin flowering, trees may be sprayed with “Cyfluthrin” to destroy young boxelder bugs. Liquid concentrate Cyfluthrin should be added to the jar of a hose-end sprayer, the dial turned to provide the proper spray as listed on the Cyfluthrin label, the deflector nozzle moved upwards at the nozzle, then a “fire stream” of Cyfluthrin sprayed on upper leaves as you walk around the tree. Plan on a second spray 7-10 days later.

Cyfluthrin is available as Bayer Advanced Spray for Insects. Shop for the liquid concentrate, not the ready-to-use product.

However, it is the army of boxelder bugs on the wall of homes in the fall that causes the greatest problems. At this time, forget pesticides and rely on citronella oil to destroy the bugs.

Fill the jar of the hose-end sprayer with citronella oil; don’t add any water to the jar. Turn the “dial spray” on the cover to apply the greatest amount of citronella. Move the deflector away from the nozzle. Turn on the hose and spray citronella oil as high up the wall of the house as possible. In most cases, the spray will reach 20 feet or so up the wall. Focus only on putting as much citronella oil on the top of the wall as possible. The idea is to let the citronella flow down the entire wall of the home. Spray only the one wall that is closest to the boxelder tree. Try to spray when no rain is forecast for at least 24 hours.

As for results, boxelder bugs cannot tolerate citronella oil. When you spray, the oil will flow down to coat the entire wall of the house. No matter where bugs congregate, they will fall to the ground when exposed to citronella oil. They will not climb the wall a second time. They will die after their first effort.

Pay special attention around windows since they are most vulnerable to attack by bugs. Spray liberally around windows to coat the area with citronella oil. If windows are screened, install storm windows first before spraying.