The question of whether stink bugs pose a threat usually refers to the invasive Brown Marmorated Stink Bug (BMSB), Halyomorpha halys. Originating in Asia, this shield-shaped insect has spread widely across North America and is primarily a nuisance pest. While its presence in homes can be alarming, the bug is generally harmless to mammals, lacking the ability to bite or sting. Its potential for large-scale crop damage, however, is significant.
Assessing the Threat to Humans and Pets
The BMSB poses no direct health or safety risk to humans or pets. Stink bugs do not possess venom or toxins, and they are incapable of biting. Their mouthparts, known as a proboscis, are designed exclusively for piercing and sucking plant fluids.
Stink bugs are not known to transmit any diseases to humans or household animals. The defensive fluid they release is non-toxic, but it can sometimes cause mild allergic reactions, such as dermatitis or a runny nose, in sensitive individuals. If a pet accidentally ingests a stink bug, the strong, unpleasant taste will likely cause only minor stomach upset or excessive drooling, but not serious poisoning.
Understanding the Nuisance Factor
The most common interaction people have with the BMSB is experiencing its signature defense mechanism: the odor. When the bug is crushed, handled, or threatened, it releases a foul-smelling chemical from glands on its abdomen to deter predators. This odor is composed of several chemical compounds, sometimes described as smelling like cilantro or a fermenting apple.
The major domestic issue is the bug’s overwintering behavior, which involves searching for warm, sheltered locations. In early autumn, adult BMSBs congregate on the sunny exterior of homes and crawl inside through tiny cracks or openings to hibernate. They often hide behind baseboards, in attics, or within wall voids, emerging during warm spells in the winter or fully in the spring.
These pests do not reproduce inside the home, nor do they feed on or cause structural damage to wood or textiles. Their presence in large numbers is a significant psychological nuisance. Crushed insects can sometimes leave minor, difficult-to-remove stains on curtains, upholstery, or walls. Infestations can sometimes reach thousands of individuals in a single structure.
Agricultural and Economic Impact
While harmless to people, the Brown Marmorated Stink Bug is considered a serious threat to agriculture. As an invasive species, it feeds on over 170 host species, including many high-value fruit, vegetable, and field crops. Both adults and nymphs use their piercing-sucking mouthparts to inject digestive enzymes and extract fluids from fruit and seeds.
This feeding causes significant damage, such as pitting, scarring, and internal tissue breakdown, which renders produce unmarketable. Crops like apples, peaches, corn, soybeans, and tomatoes are particularly vulnerable to this type of injury, often resulting in cosmetic flaws referred to as “cat facing.” The economic cost of control and crop loss due to this pest has been substantial in affected regions.
The BMSB’s ability to fly long distances, sometimes up to 70 miles per day, allows it to rapidly expand its range and spread damage across agricultural landscapes. Managing this pest is challenging because it has few natural predators and chemical control options are often limited or ineffective.
Safe Removal and Exclusion Strategies
Since the BMSB is known for its home-invading behavior, prevention and safe removal are the most practical steps for homeowners. Exclusion is the most effective defense, focusing on sealing all potential entry points before the overwintering season begins in the fall. This includes using quality silicone caulk to seal cracks around window frames, door trim, utility pipes, and chimneys.
Damaged window screens and door sweeps should be repaired or replaced to eliminate easy access points. For indoor removal, vacuuming is an effective method. It is recommended to place a stocking inside the vacuum hose to capture the bugs before they enter the canister, which can otherwise acquire the unpleasant odor. The contents of the stocking should be immediately emptied into soapy water to drown the insects, as this solution overcomes their ability to float.
Physical removal into a container of water mixed with dish detergent is another non-toxic and highly recommended strategy. It is important to avoid squashing the bugs, as this triggers the release of the odor that can permeate the living space. Interior pesticide applications are generally not recommended. They are ineffective against bugs hiding in voids and introduce unnecessary chemicals into the home environment.