Insect Update With Phil Pellitteri

Featured in this Show

• Late Summer Means Boxelder Bug Season

  While it feels like the middle of summer this week with high temperatures and humidity through much of the state, we’re actually at a big transition point weather-wise. And that means a lot of activity in the natural world, including by our insects.

  Phil Pellitteri is an entomologist and head of the UW-Madison Insect Diagnostic Lab. He says that one of the insects we’re likely to see a lot of soon is boxelder bugs. “Typically, what I predict is a very dry late-summer means lots of boxelder bugs. So I’m getting nervous. And of course last year was very dynamic because they even had an extra generation. So, we’ll wait and see. I’ve not had indications they’ve started yet, but it would not surprise me if in the next week or two they they’ll start those congregations and clustering on sunny sides of buildings.”

  Late summer is important for them because they are looking for good locations for hibernation. “They’re done feeding, done breeding. They’re a foul-tasting animal, so they cling together so there’s protection in numbers,” Pellitteri explains.

  The natural control of their population is actually a fungal disease. But as Pellitteri notes, fungus doesn’t thrive in hot, dry conditions, so that’s why that weather indicates a bumper crop of boxelders.

  Unlike some other insects that can be quite destructive, Pellitteri says that the boxelder bugs are really just a nuisance. But unfortunately, if they decide to hibernate in the walls of your home, “you’ll pay for it for the next six months, and there’s not a whole lot that can be done. That’s why in early September, if you’ve had a tradition of having trouble with them, that’s the time to try and stop them before they get in.

  A UW Extension Horticulture publication that Pellitteri authored along with Rebecca Hoffman offers these suggestions for control and exclusion. “Removing all boxelder trees in an area will prevent breeding. Caulking windows and doors, and repairing window and door screens will prevent bugs from entering a home. You can also vacuum the bugs up with a hose attachment (to avoid staining fabric), but if vacuuming, dispose of the vacuum contents immediately or bugs can crawl out. If you decide you would like to spray for control, one home remedy is to use a 3-4% mix of water and soap (by volume) that can be sprayed directly on the insects. Remember however that soaps only kill on contact. You can also have a professional apply insecticides to the sides of your home. Some insecticides are ineffective at cool temperatures, but insecticidal soap or sprays containing permethrin, cyfluthrin or esfenvalerate are effective.”