The term “black jack bug” informally refers to common dark-colored insect pests that can become a nuisance in gardens and homes. This guide clarifies what these bugs might be and provides strategies for their prevention and control.
Identifying the Black Jack Bug
What “Black Jack Bug” Might Mean
The informal term “black jack bug” typically refers to dark-colored insects that infest gardens and homes. Common culprits include the boxelder bug (Boisea trivittata) and various stink bug species, such as the brown marmorated stink bug (Halyomorpha halys) and rough stink bugs (Brochymena spp.).
Key Features for Identification
Boxelder bugs are about 1/2 inch long, black with distinctive orange or red markings, including three stripes behind their head and red wing edges forming an ‘X’ shape when at rest. Nymphs are initially bright red, gradually developing black markings. Brown marmorated stink bugs are shield-shaped, 1/2 to 5/8 inch long, mottled brown with lighter antennal bands and alternating dark and light bands along their abdomen. Rough stink bugs (Brochymena genus) are also shield-shaped, broad-bodied, mottled gray and black, and range from 10 to 22 mm.
Common Habitats
Boxelder bugs primarily inhabit boxelder, maple, and ash trees, feeding on seeds and leaves. They often congregate on sunny building surfaces in late summer and fall, seeking sheltered overwintering spots. Stink bugs are polyphagous, feeding on various fruit, vegetable, and ornamental plants. Both types seek sheltered locations, like home crevices, to survive colder temperatures.
Damage and Nuisance
Plant Damage
Boxelder bugs typically cause minor cosmetic damage to plants by feeding on seeds and leaves, leading to slight leaf curling, yellowing, or spots. While generally nuisance pests, large infestations can sometimes deform young fruits. Stink bugs inflict more significant damage. They extract plant sap, resulting in discolored spots, distorted growth, and pitting or scarring on fruits and vegetables, potentially rendering them unmarketable. On corn, feeding can cause shriveled kernels, stunted plants, or tillering.
Indoor Annoyances
When temperatures drop, these bugs often seek indoor refuge, becoming a nuisance. They congregate on walls, around windows, and in crevices. When disturbed or crushed, both release a foul odor, which can stain walls, curtains, and other fabrics. While they do not bite people or pets and cause no structural damage, their presence in large numbers can be bothersome.
Prevention Strategies
Outdoor Prevention
To minimize outdoor populations, remove female boxelder trees, a primary food source for boxelder bugs. Maintain garden hygiene by clearing leaf debris and overgrown vegetation around the home’s foundation to eliminate hiding places. Proper drainage and sealing foundation cracks also deter them from establishing populations near structures.
Indoor Prevention
Preventing indoor entry is an effective strategy. Seal cracks and crevices around windows, doors, utility pipes, and foundations. Repair damaged window or door screens and ensure proper weather stripping to block access. As these bugs are attracted to warm areas and light, turning off unnecessary outdoor lights can also reduce their attraction to your home.
Control Methods
Non-Chemical Approaches
For indoor infestations, physical removal is practical. Vacuuming bugs is effective; immediately dispose of the vacuum bag or empty the canister to prevent odors. For outdoor populations, a strong spray of soapy water (about 5 tablespoons dish soap per gallon) kills boxelder bugs on contact. For stink bugs, a solution of water and dish soap, or hot water, impairs their exoskeleton. Hand-picking bugs from plants into soapy water is also an option, especially when they are less active.
Chemical Options
For severe outdoor infestations or when non-chemical methods are insufficient, targeted insecticide applications may be considered. Perimeter treatments around the home in late summer or early fall can prevent entry. Products containing bifenthrin, cyfluthrin, deltamethrin, or permethrin are commonly used for boxelder bugs. For stink bugs, pyrethrin can be effective on contact, but may also affect beneficial insects. Always read and follow product label directions, ensuring suitability and safety; consulting a pest control professional is beneficial for persistent infestations.