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The Ultimate Guide to Rodent Control
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The boxelder bug life cycle drives when and how these nuisance pest invade homes. As a registered technician with four years in the field and part of a third generation family business in the DMV for over 50 years, I’ve seen them swarm siding every fall. This guide explains each stage and what that means for your control plan.
The boxelder bug is a nuisance pest known for gathering on warm building exteriors. You’ll see boxelder bugs clustering around windows and doors on sunny days. They live on warm surfaces as they search for a place to spend winter.
These insects (Boisea trivittata), sometimes called the box elder bug, belong to family Rhopalidae and order Hemiptera. They’re true bugs about half an inch long with bold red markings and three red lines behind the head. They use piercing and sucking mouthparts to feed on sap and seedpods.
Out west, you may spot the western boxelder bug (Boisea rubrolineata), a close relative with similar habits.
In fall, boxelder bugs swarm south- or west-facing walls before they invade homes. They can travel as far as two miles to find a warm spot. A single infestation can grow rapidly, and the number of boxelder bugs inside can climb from a few to hundreds.
You can prevent them from entering your home by sealing vent gaps, screens, and small openings around doors.
Understanding the life cycle helps you time treatments for each stage. Bugs start emerging in early spring as adults fly to nearby trees. Eggs hatch into nymphs, nymphs develop into adults, and a second wave may occur in late summer.
In early spring, adult boxelder bugs lay clusters of eggs in bark crevices. Bugs lay eggs on the underside of leaves and seedpods. Eggs are laid in early spring and hatch in 7 to 14 days, according to the UNH Extension.
After 7 to 14 days, nymphs emerge bright red and wingless. These nymphs develop through five instars, and as they molt they gain black patches. Nymphs develop into adults over about eight to twelve weeks, roughly 50–78 days in warm weather.
You can treat clusters of young bugs with insecticidal soap or a simple soapy water spray to reduce numbers early.
During the summer, adults feed on maple or ash seeds and foliage. As cooler weather arrives, they gather on tree trunks and warm siding to prepare to overwinter. By fall, these adults invade homes through cracks and crevices.
In warm years, a second generation emerges by August and September, extending the bug life span and boosting populations. Boxelder bugs can fly long distances and may fly miles to find an overwintering wall.
In spring (April–May), overwintered adults fly to box elder and maple trees in your yard to feed and mate. Nymphs feed in June and July on leaves and seedpods. By September, adults seek shelter and hibernate in walls, attics, or under bark until spring returns.
In fall, adults invade homes and other buildings through small gaps around windows and doors. Seal cracks around the foundation and use caulk on crevices. They hide in wall voids and the attic until warm days lure them back outside.
Female box elder trees and seedpods are the main source of food for these bugs. Consider removing boxelder trees closest to your house to significantly reduce the number of boxelder bugs near your home. Boxelder bugs cause little damage but can harm young plants under heavy pressure.
Buildings with unsealed vents, gaps under siding, or damaged screens invite boxelder bugs. Fill cracks and crevices around windows and doors. Use caulk on gaps and install weather stripping on doors to block common entry points.
Time treatments to each stage: target nymphs in early summer when they feed openly, and focus on adults in early fall before they hibernate. Reserve pesticide treatments for heavy outbreaks and try non-chemical methods first.
Seal cracks around the foundation.
Fix or replace torn screens on vents.
Apply weather stripping on exterior doors.
Trim back shrubs so they don’t touch siding.
Indoors, skip sprays and sweep or vacuum stray bugs with a hose attachment or broom. A quick pass with a vacuum saves on mess and stain. Outdoors, you can use a soapy water spray or insecticide barrier if clusters are heavy. For large problems, professional pest removal can include a targeted perimeter spray.
Consider removing boxelder trees closest to your house. Removing boxelder trees cuts egg-laying sites and removes seedpods. It can significantly reduce the number of boxelder bugs you see. However, these bugs cause little damage, and removal may not suit every yard.
Boxelder bugs may also scavenge dead insects but do very little harm to plants. Unlike a milkweed bug, they rarely hit flower gardens. Broad sprays risk killing pollinators and beneficial insects. Non-chemical methods help protect the local ecosystem.
Boxelder bugs do not breed indoors. They hover in wall voids to hibernate, but will not lay eggs inside. Boxelder bugs become active only on warm days in winter, and boxelder bugs are found only near host trees or on warm exterior surfaces—not in pantries or fabrics.
Call Better Termite & Pest Control today for professional pest control service at 703-683-2000 or email [email protected]. Our licensed technicians are ready to help with questions or an estimate.
A boxelder bug typically lives for several months. Adults can survive through winter and live into early summer of the next year, making the bug life span close to one year in mild climates.
You’ll see boxelder bugs cluster on your home mainly from September through November and again briefly in spring when they leave their overwintering sites.
To control them, seal cracks and entry points, remove nearby seedpods, and vacuum or sweep bugs indoors. A soapy water spray outdoors can knock down clusters on siding.
They swarm when they’re clustering around sunny walls preparing to hibernate. On warm fall afternoons, they gather in large numbers before invading your home.
No. Boxelder bugs breed only on trees. While they hide indoors for winter, they won’t lay eggs or form a breeding colony inside your home.
With five years of hands-on experience in the pest control industry, George Schulz is a registered technician with the Virginia Pest Management Association and a proud third-generation professional in a family business that’s been protecting homes for over 57 years. He manages and trains a team of service pros while also leading internal research efforts—recently spearheading a deep-dive review of thousands of documents on pest control materials to hand-pick the most kid and pet friendly, most effective solutions tailored specifically for homes in the DC metro area. Read his bio.
