BOXELDER BUG Integrated Pest Management for Home Gardeners and Landscape Professionals The western boxelder bug (Boisea rubrolineata) is often a nuisance pest around and in homes. Boxelder bugs usually feed on the leaves, flowers, and seedpods of the female or seedbearing box elder tree (Acer negundo), although they may also subsist on male box elder trees and occasionally occur on maple and ash trees. They may feed on the fruits of almond, apple, cherry, peach, Figure 1. Boxelder bug adult and nymphs. Figure 2. Young nymph of western box- pear, and plum trees, and on grapes, (J. K. Clark) elder bug, Boisea rubrolineata. where their feeding punctures cause (J. K. Clark) the fruit to become deformed. Large numbers of the bug usually occur only on female box elder trees. IDENTIFICATION When full grown, the boxelder bug is about 1/2 inch long and one-third as wide. Adults are mostly black and have three red lines on the pronotum of the thorax (one down the middle and on each margin) and several fine Figure 3. Boxelder bug eggs on leaf. Figure 4. Adult squash bug. red lines on each wing (Figure 1). The (J. K. Clark) (J. K. Clark) wings lie flat on the bug’s back when it is at rest. The abdomen is red. The young nymphs are bright red (Figure 2) and when approaching adulthood, become marked with black and begin to develop black wing pads. Eggs are yellow when first laid but become red as nymphs develop inside (Figure 3). Boxelder bugs are true bugs (Order: Hemiptera) in the family Rhopalidae. Figure 5. Adult bordered plant bug, Figure 6. Small milkweed bug, Lygaeus They are sometimes confused with Largus sp. (J. Gross, UC Berkeley) kalmii. (Jon Yuschock, Bugwood.org) other true bugs including squash bugs (Anasa spp., family Coreidae) (Figure 4); the bordered plant bug (Largus cinc- tus, family Largidae) (Figure 5); small milkweed bug (Lygaeus kalmii, family Lygaeidae) (Figure 6); leaffooted bugs (Leptoglossus spp., family Coreidae) (Fig- ure 7); and the red-shoulder bug (Jadera haematoloma, family Rhopalidae) (Fig- ure 8). The three lengthwise red lines on the pronotum distinguish boxelder Figure 7. Adult leaffooted bug. Figure 8. Red-shouldered bug, Jadera bugs from these other species. (J. K. Clark) haemalotoma. (J. Gross, UC Berkeley) PEST NOTES Publication 74114 Statewide Integrated Pest Management Program July 2014 July 2014 Boxelder Bug LIFE CYCLE vigilance may be required during fall walls or tree trunks with a forceful migration. Outdoors, eliminate hiding stream of water. In spring, the overwintered female places and debris and consider remov- bugs lay eggs in the cracks and crev- ing female box elder trees. Insecticide ices of the box elder tree’s bark, and Chemical Control use is rarely justified. the nymphs hatch in a few days. The Insecticide sprays are generally not nymphs grow larger and develop into recommended for boxelder bug man- adults during the summer. They then Elimination of Host Trees agement. They are often no more effec- mate and lay eggs that hatch into the Since the box elder tree is the main tive than vacuuming and hosing, and nymphs of a second generation. Adults source of food for the boxelder bug, repeated applications may be required. and nymphs periodically migrate removing the trees, especially the fe- Insecticidal soap applied in a forceful in large groups, often covering tree male or pod-bearing trees, is the most spray of water may reduce populations trunks, the ground, fences, and the effective way of controlling the pest. Be on tree trunks. Pyrethroid insecticides sides of houses. careful not to plant or allow the estab- are available for treating foundation lishment of new box elder trees in your walls around the perimeter of build- Most of the nymphs of the second gen- yard. ings. If required, these applications are eration grow to full size in August and best done by a professional. Special September. In fall, the adults seek over- However, elimination of trees on your care must be taken to avoid runoff of wintering places in dry, sheltered hol- property won’t always completely pesticides from walls and foundations low tree trunks; under rocks, boards resolve the problem. Winged adults into storm drains, because they lead and other debris; in cracks and crevices can fly for distances of several blocks, directly into creeks and rivers. Do not in walls; in door and window casings; so boxelder bugs may also migrate in use sprays for boxelder bugs inside the around building foundations; and from a neighbor’s tree. house. inside houses. They become a nuisance outdoors on patios or indoors when If removal of trees is not an option, REFERENCES they invade in significant numbers. On clear fallen seeds from beneath and Davis, C. S., and J. J. Joos. 1975. Box El- warm days during winter and early near trees. Use a broom or shop vacu- der Bug. Oakland: Univ. Calif. Div. Ag- spring, boxelder bugs sometimes ap- um on hard surfaces such as patios and ric. Nat. Res. Leaflet 2790. (out of print) pear on light painted surfaces outdoors driveways. A shop vacuum will also on the south and west sides of the remove most seeds from grassy areas. house, resting in the sun. Dreistadt, S. H. 2004. Pests of Landscape Exclusion and Sanitation Trees and Shrubs. 2nd ed. Oakland: Univ. Calif Agric. Nat. Res. Pub 3359. DAMAGE Repair torn screens and close up places The bugs do little damage to orna- where the bugs can enter the house, Ebeling, W. 1975. Urban Entomology. mental trees. They may occasionally such as cracks around doors and win- Oakland: Univ. Calif. Div. Agric. Nat. cause puckering or distortion of fruit dows and attic or basement vents. Use Res. in commercial orchards such as pear caulk, weatherstripping, fine-mesh or kiwi, but this is rarely a significant screen, steel wool, or expandable foam problem. They do not injure people or as appropriate. Boxelder bugs that enter pets; but when they come indoors, they the home may be controlled by hand- can be annoying and may spot curtains, collecting or vacuuming. Repeat as furnishings, and clothing with their needed. excrement. When crushed, they give off an offensive odor. They do not breed Eliminate hiding places such as piles of indoors. If trapped in basements or rocks, boards, leaves, and general de- houses, they will eventually die. bris close to houses. Boxelder bugs hide during the day or overwinter in these MANAGEMENT sites. Rake leaves and remove weeds Boxelder bugs do not cause signifi- and grass from a 6- to 10-feet wide strip cant damage to landscape plants, and around the foundation, particularly on management need only be directed at the south and west sides of the house. keeping them out of homes, where they Keep box elder tree seeds swept up. may become a nuisance. If boxelder A weed and debris-free area tends to bugs frequently invade homes, seal up reduce the congregation of bugs near entry points such as cracks and screen the foundation. windows and doors. Sanitation prac- tices such as vacuuming can be used Boxelder bugs are susceptible to to reduce population numbers, but drowning, so wash boxelder bugs off ◆ 2 of 3 ◆ July 2014 Boxelder Bug . AUTHORS: E. J. Perry, UC Cooperative To simplify information, trade names of products Extension emeritus, Stanislaus Co.; have been used. No endorsement of named K. Windbiel-Rojas, UC Statewide IPM products is intended, nor is criticism implied of Program. similar products that are not mentioned. This material is partially based upon work TECHNICAL EDITOR: M. L. Flint supported by the Extension Service, U.S. EDITOR: K. Beverlin Department of Agriculture, under special project Section 3(d), Integrated Pest Management. This and other Pest Notes are available at Produced by: www.ipm.ucanr.edu. Statewide Integrated Pest Management Program University of California For more information, contact the University of 2801 Second St. California Cooperative Extension office in your Davis, CA 95618-7774 county. See your telephone directory for addresses and phone numbers, or visit http://ucanr.edu/ County_Offices/. University of California scientists and other qualified professionals have anonymously peer reviewed this publication for technical accuracy. The ANR Associate Editor for Pest Management managed this process. WARNING ON THE USE OF CHEMICALS Pesticides are poisonous. Always read and carefully follow all precautions and safety recommendations given on the container label. Store all chemicals in the original, labeled containers in a locked cabinet or shed, away from food or feeds, and out of the reach of children, unauthorized persons, pets, and livestock. Pesticides applied in your home and landscape can move and contaminate creeks, rivers, and oceans. Confine chemicals to the property being treated. Avoid drift onto neighboring properties, especially gardens containing fruits or vegetables ready to be picked. Do not place containers containing pesticide in the trash or pour pesticides down the sink or toilet. Either use the pesticide according to the label, or take unwanted pesticides to a Household Hazardous Waste Collection site. Contact your county agricultural commissioner for additional information on safe container disposal and for the location of the Household Hazardous Waste Collection site nearest you. Dispose of empty containers by following label directions. Never reuse or burn the containers or dispose of them in such a manner that they may contaminate water supplies or natural waterways. ANR NONDISCRIMINATION AND AFFIRMATIVE ACTION POLICY STATEMENT It is the policy of the University of California (UC) and the UC Division of Agriculture & Natural Resources not to engage in discrimination against or harassment of any person in any of its programs or activities (Complete nondiscrimination policy statement can be found at http://ucanr.edu/ sites/anrstaff/files/183099.pdf).