When should I treat for boxelder bugs in Davenport?
Book in September or early October, when you first see boxelder bugs gathering on sunny walls but before cold nights drive them into the siding. In many Davenport years that window opens around mid-September. Once the bugs are tucked inside wall voids and attics, outdoor treatments can no longer reach them.
Watch the south and west walls on the first warm afternoons after a cool night. Call when you see a few dozen; by the time there are thousands, many have already found a way in.
The Quad Cities pest calendar shows how this window lines up with mice moving in and the other fall invaders, so you can plan one visit instead of three.
- Early September: watch the sunny walls for the first small groups
- Mid-September to early October: book the perimeter treatment and sealing
- After hard freezes set in: outdoor treatment does little, so vacuum what gets inside
- March and April: survivors head back out, so note where they appear
Are boxelder bugs harmful?
Boxelder bugs are a nuisance, not a danger. They do not sting, rarely bite, do not reproduce indoors and do not damage the house or what is in it. Their droppings and crushed bodies can stain fabric and paint, and large numbers on windows and walls are unpleasant, but they cause no structural harm.
Outdoors they do little damage to plants, mostly feeding on boxelder seeds. Some people find the mild odor of crushed bugs unpleasant, which is one more reason to vacuum instead of swatting.
Stains are the real cost. Boxelder bug droppings are reddish-orange and set into light fabric, so keep the bugs off drapes and bedding and blot spots promptly rather than rubbing them deeper.
Does cutting down a boxelder tree get rid of the bugs?
It can reduce them, but rarely ends the problem. Boxelder bugs feed mostly on seed-bearing female trees, and removing one next to the house takes away a nearby food source. The bugs can fly in from trees several lots away, though, so the sunny walls of your house stay attractive every fall.
Male boxelders do not produce seeds, so they support far fewer bugs. If you are planting, ask a nursery about other shade trees instead.
Before cutting anything, check whether the tree is yours, a neighbor's or in the city right-of-way along the alley.
If you do take one down, grind the stump. Boxelders sprout back fast from cut stumps and roots, and a thicket of new shoots near the house is the opposite of what you wanted.
Why do boxelder bugs show up inside on warm winter days?
Bugs hiding in the walls warm up when sun heats the siding during a January or February thaw, and some crawl toward the warmth of the living space instead of back outside. They are not a new infestation. They are the same bugs that moved in last fall, and they cannot reproduce indoors.
They usually turn up on south-facing windows, around light fixtures and near outlets on exterior walls. A few at a time is normal for a house that was not sealed before fall.
How do I get rid of boxelder bugs already in the house?
Vacuum them with a shop vac or a vacuum you can empty outside right away, then seal the bag. Do not crush them on curtains, carpet or walls, because they stain. Indoor spraying does little, since most of the bugs are hidden in wall voids. Sealing their entry gaps before next fall is the long-term fix.
Check where they are coming from: a light fixture, a window frame, an outlet or attic hatch. Those spots tell the technician which exterior gaps to close.
