top of page

The Box Elder Beetle


The Box Elder Beetle

BOX ELDER BUG, A/K/A Pop Bug, Populist Bug, Grass Bug, Democrat Bug and Cottonstainer Originally Leptocoris trivittatus (eastern) (Say) and l. rubrolineatus (western) (Barber)


The eastern scientific name has been changed to Boisea trivittata (Say) and the western scientific name

to Boisea rubrolineata


Class - Insecta Order - Heteroptera Family - Rhopalidae


The conspicuous black-and-red box elder bugs are divided into two species. Box elder bugs undergo gradual/simple metamorphosis. The eastern species grows to be about 1/2” long; it is distributed as far west as Nevada, while the slightly smaller western species ranges in California and Oregon. These elongate-oval bugs lay eggs in the spring basically on female or pod-bearing box elder trees.


The young nymphs are bright red. Dark markings become more apparent on older nymphs. Eastern nymphs feed primarily on the female Box elder tree (Acer negundo, Linnaeus) foliage, tender twigs, and winged seed pods. The Western box elder bug primarily feeds on Acer macrophyllum (another box elder) other maples, almonds, apples and other fruit. In late summer, mature nymphs and adults crawl down the tree trunk by the hundreds and disperse. Adults also fly directly from the tree into houses. Like attic (cluster) flies, the bugs find spaces under siding, around window and door facings where they enter wall voids and rooms in houses.


Box elder bugs seek overwintering shelter outdoors in tree hollows, as well as in sheds, barns and houses.

Those that find harborage indoors move around and fly on warm winter days.


Habitat Alteration


The best management method is to find at least any/all female box elder trees and remove them. These “trashy” trees are seldom planted as ornamental shade trees; they seed themselves and grow as weed trees, and are not eliminated mainly because they are difficult to identify. Their branches break easily in storms, they have messy seeds and are short-lived. Their leaves, somewhat like maples, are variably shaped on the same tree. Seed pods are helpful in the identification of the female trees. It usually takes a large invasion before tree removal is practiced.


  • Caulk around entry points on the building foundation and door and window facings. At times it may be

necessary to caulk other points of entry indoors. Lightly dust with food-grade DE.


Intelligent Pest Management® Control


  • Seal all cracks and crevices, and/or dust with talcum powder or medicated body powder or food-grade DE.

  • Remove infested trees.

  • Vacuum or steam clean bugs inside.

  • Detergents have also been shown to kill these bugs. Use Safe Solutions, Inc. food-grade diatomaceous earth or spray them with Not Nice to Bugs® or Safe Solutions Enzyme Cleaners with Peppermint. They are especially vulnerable when they congregate on buildings. Vacuum them up or steam clean them.




Egg - Initially straw-yellow in color turning dark reddish-brown in color, normally deposited on female box elder leaves, stones, grass, bark, shrubs and trees in the spring. Turn red as the embryos develop and hatch in about two weeks.


Nymph - Resembles adult in appearance but smaller, first instars are wingless and bright red in color and sparsely covered with bristles; 5 instars; last stage dark red in color with slate black wing pads.

Treatment of Box Elder Beetles

Inside the building, vacuum up all invaders, make no other control to kill them inside. Lightly dust with talcum or medicated body powder or Safe Solutions, Inc. food-grade DE. Outside the building caulk or seal all openings with duct tape or steel wool all cracks, crevices, and other openings. Install weather-stripping and screening on all doors and windows, especially wherever you observe them gaining entrance. Remove and replace all elm trees with a more desirable species. If you must use a pesticide poison (as a last resort) inside, use a dust, e.g., boric acid or silica aerogel per label directions (treat like cockroaches). The pathogen bacterial Bacillus thuringiensis, var. San Diego will also destroy adult elm leaf beetles, as will the mini-wasp, parisitoid Tetrastichus galerucae, which lays its egg inside the egg stage of elm leaf beetles where it hatches and eats the embryo. Milky spore disease used on turf areas and neem sprayed on trees will also control this beetle.

bottom of page