Western boxelder bug

Western boxelder bugs are flat, dark gray to black, about one-half inch long, with distinctive red striping on the abdomen. Nymphs are reddish. You will see them clustering on boxelder trees, maples, and ash species in late summer and fall. Although adults and nymphs feed on developing seeds, damage to ornamental maples is minimal. Their primary concern is aggregating on house walls in fall.

Prune female boxelder trees in late spring to reduce seed production and lower insect numbers. For landscape trees, no chemical control is needed since damage to foliage and seeds is trivial. Do not use pesticides on ornamentals for boxelder bug management. If aggregations become a household nuisance, contact a pest management professional for building-perimeter control tactics.