Order: Hemiptera
Family: Rhopalidae
Boisea trivittata
Overview
The boxelder bug is not typically a damaging plant pest. The insect feeds primarily on the seeds of its host plants, but some feeding on leaves and twigs can occur. However, their behavior of gathering in large numbers or groups can make them a nuisance to some observers. As its name would suggest, the boxelder bug is associated with boxelder (Acer negundo) and can become a nuisance on outdoor structures by the fall. Homes and other buildings with these trees in close proximity should have all vents, attic louvers, screens or other potential openings in good repair to prevent entry of these insects in the building. While their presence may be annoying to some, the boxelder bug is not a structural pest and will not damage homes. Boisea trivittata is native to North America and can have multiple generations per year.
Host Plants
The main host for the boxelder bug, as the common name suggests, is the boxelder (Acer negundo). The insect can also be found on silver maple (Acer saccharinum) as well as the fruit of apple or plum, occasionally.
Identification/Life Cycle
This insect is known from eastern Canada throughout the eastern United States. It is mostly considered a pest when adults try to enter homes to overwinter. They will gather in groups on the south sides of trees, buildings, and rock faces exposed to the sun. After they gather in large amounts, they will fly together to homes or buildings, searching for a place to overwinter. When in the building, they do not cause structural damage. They do not bite or sting people. They are primarily viewed as a nuisance by those who do not want to share their living space with them.
In the spring, they leave their overwintering shelter and seek out expanding boxelder buds, where they will lay eggs between late-April and early-May in the cracks and crevices of boxelder bark or surrounding sheltered areas. Eggs change in color from yellow to red as they mature. Eggs may take 10-14 days to hatch. Nymphs are red when they emerge from hatched eggs and feed on fallen boxelder seeds. First instar nymphs are approx. 1.3 mm in length, with bright red abdomens and black wing pads, legs, and antennae. The color of the nymphs changes to a darker red as they mature and pass through 5 nymphal instars. Adults are dark brown to black in color, with three red lines (two on the sides, one down the center) of the thorax. They also have red lines on the margins of the hardened half of the hemelytra (wings). Adults are up to 12 mm (approx. ½ inch) long and appear flattened from the top. Up to two generations may occur per year, depending on local temperatures. The boxelder bug remains active throughout the growing season.
Damage
Boxelder bugs are often a nuisance household pest in the fall as adults seek shelter. (Boxelder bugs do not cause structural damage in buildings. They are also unable to complete their life cycle or reproduce within buildings.) Be sure all window screens fit snugly and close any gaps/openings that would allow entry into the home. Foliage and twigs of female boxelder (Acer negundo) may be impacted slightly. May cause foliar distortion, bronzing, or stippling as they feed with piercing-sucking mouthparts, especially on newly developing leaves. Generally not a threatening pest to boxelder. Feeds on seeds of female boxelder; remove female boxelder trees, if necessary, to reduce populations seeking overwintering shelters. Adults fly long distances, so removing trees may not be entirely effective as additional hosts on neighboring properties may be located close enough to provide a population looking to overwinter.
Management Strategies:
Management of the boxelder bug is not frequently necessary. Mechanical exclusion is the best method of preventing boxelder bugs from entering homes and buildings. Seal up openings from the outside to the inside of homes and buildings to prevent their entry. After boxelder bugs enter a building or home, chemical management is not recommended (inside homes). If numerous boxelder bugs are found indoors, locate the opening where the insects are entering and physically prevent them from entering (repair window screens, caulk cracks, etc.). For both live and dead boxelder bugs found in the home, they can be removed using a vacuum cleaner. Be sure to empty the bag or dustbin where the insects get trapped directly after using the vacuum. You may need to empty dustbins outdoors, or seal up bags inside a plastic trash bag.
Cultural/Mechanical Management:
Be sure all window screens fit snugly and close any gaps/openings that would allow entry into the home. Remove from indoor locations using a vacuum. Empty the vacuum after each use. Chemical management inside the home for boxelder bug is not recommended or necessary.
Biological Control/Natural Enemies:
Green anoles (Anolis carolinensis) are reported as would be predators of boxelder bugs in Alabama. However, when encountered, the anoles avoid predation of the insects. House cats have also been observed to spit them out. This is attributed to distasteful volatile chemicals present in boxelder bugs (defensive chemicals that help them avoid predation) (Palazzo and Setzer, 2009).
Additional research suggests that the boxelder bug is “exceptionally free of insect parasites”. McCulloch (1916) found that adult boxelder bugs intestinal tracts were full of parasitic flagellates, however that the insects were not harmed by this association. Birds such as robins, black birds, thrashers and sparrows are not observed to feed on boxelder bugs, again likely due to the defensive chemicals they possess. Only spiders were observed feeding on them. No fungal pathogens were observed either (Shepherd, 1932).
Chemical Management:
There are products available containing the following active ingredients labeled for use against boxelder bug on ornamental trees and shrubs (outdoors) in Massachusetts: acephate (NL), azadirachtin (NL), carbaryl (L), cyfluthrin (NL), cypermethrin (NL), deltamethrin (L), gamma-cyhalothrin (L), horticultural oil (L), lambda-cyhalothrin (L), permethrin (L), pyrethrins (L), tau-fluvalinate (NL) and zeta-cypermethrin (L).
Chemical management of boxelder bugs on host trees is not necessary to protect the overall health of the host plant, since this insect is often not very damaging to its host. It may be considered on landscape specimens that are attracting boxelder bugs, which in the fall may seek overwintering shelters in nearby homes, if that is a problem. However, chemical management of this insect is often not necessary.
Active ingredients that may be applied systemically include: acephate (injection) and azadirachtin (injection, soil drench).
Make insecticide applications after bloom to protect pollinators. Applications at times of the day and temperatures when pollinators are less likely to be active can also reduce the risk of impacting their populations.
Note: Beginning July 1, 2022, neonicotinoid insecticides are classified as state restricted use for use on tree and shrub insect pests in Massachusetts. For more information, visit the MA Department of Agricultural Resources Pesticide Program.
Read and follow all label instructions for safety and proper use. If this information contradicts language on the label, follow the most up-to-date instructions on the product label. Always confirm that the site you wish to treat and the pest you wish to manage are on the label before using any pesticide. Active ingredients labeled "L" indicate some products containing the active ingredient are labeled for landscape uses on trees or shrubs. Active ingredients labeled "N" indicate some products containing the active ingredient are labeled for use in nurseries. Always confirm allowable uses on product labels. This active ingredient list is based on what was registered for use in Massachusetts at the time of publication. This information changes rapidly and may not be up to date. If you are viewing this information from another state, check with your local Extension Service and State Pesticide Program for local uses and regulations. Active ingredient lists were last updated: September 27, 2024. To check current product registrations in Massachusetts, please visit the MA Department of Agricultural Resources Pesticide Product Registration page and click on "Search Pesticide Products Registered in Massachusetts - Kelly Solutions".
References
Palazzo, Maria C., and William N. Setzer. "Monoterpene hydrocarbons may serve as antipredation defensive compounds in Boisea
trivittata, the boxelder bug." Natural Product Communications 4.4 (2009): 1934578X0900400401.
PennState Extension: Boxelder Bug Fact Sheet
Shepherd, Byron Leroy. The life history and control of the boxelder bug (Leptocoris trivittatus)(Say)(Coreidae), with special
reference to Kansas. Diss. Kansas State University, 1933.
UMass Extension Insect Management Guide
Authors
Updated by Tawny Simisky.