The brown marmorated stink bug, Halyomorpha halys, has become a significant concern. This insect has emerged as a pervasive presence in many areas. Its widespread establishment has led to discussion regarding its impact on agricultural systems and residential environments.
Identifying the Brown Marmorated Stink Bug and Its Origins
The brown marmorated stink bug is distinguishable by its physical characteristics. Adults measure between 12 to 17 millimeters in length and 7 to 10 millimeters in width, possessing a “shield” shape. Their dorsal coloration is brownish and mottled, or “marmorated,” with dense punctation.
Identifying features include alternating light and dark bands on their antennae and along the edges of their abdomen. The underside of the insect is pale gray, with a triangular plate visible between its wings. Nymphs are initially reddish but turn almost black, then brown as they grow, and all instars have deep red eyes.
This insect is an invasive species, native to East Asia, including China, Japan, Korea, and Taiwan. Its introduction to new regions, particularly North America and Europe, occurred accidentally, often as stowaways in international trade. The first documented specimen in the United States was collected in Allentown, Pennsylvania, in September 1998. Since then, it has spread across many U.S. states and established populations in countries like Switzerland, France, Italy, Germany, Canada, and South America.
Agricultural and Household Impacts
The brown marmorated stink bug causes substantial economic damage across agricultural crops. Both nymphs and adults feed by piercing plant tissues and sucking out juices, leading to specific types of injury. This feeding can result in dimpling, discoloration, and necrotic spots on fruits and vegetables, often causing deformation and premature fruit drop.
The damage can render produce unmarketable as fresh products and, in severe cases, even unusable for processing. Crops particularly affected include apples, peaches, pears, cherries, corn, soybeans, tomatoes, and peppers. For instance, in 2010, the mid-Atlantic United States experienced significant losses, including an estimated $37 million in apple crops, with some stone fruit growers losing over 90% of their yield.
Beyond agriculture, Halyomorpha halys becomes a nuisance in homes, especially during cooler months when they seek shelter for overwintering. They aggregate on the outsides of buildings and can enter structures through cracks around windows, doors, or utility interfaces. Once inside, they do not cause structural damage or reproduce, but their presence can be distressing. When disturbed or crushed, they emit a strong, unpleasant odor from scent glands, a defense mechanism.
Managing Brown Marmorated Stink Bug Populations
Preventing brown marmorated stink bugs from entering homes involves exclusion methods. Inspecting and repairing damaged window and door screens is an important step. Sealing cracks and crevices around windows, doors, and utility entry points with silicone caulk or insulating foam sealant can block access.
For bugs already inside, removal methods should avoid pesticides for indoor use. Vacuuming them up and then emptying the contents into a sealed bag for disposal is an effective non-pesticide method. Another option is to collect them and submerge them in a bucket of soapy water, which will kill them.
In agricultural settings, managing brown marmorated stink bug populations involves integrated pest management (IPM) principles. This multi-faceted approach includes monitoring pest levels using traps and visual surveys to determine the need for intervention. Biological control agents, such as the samurai wasp (Trissolcus japonicus), a natural egg parasitoid, are being implemented to regulate populations. Targeted pesticide applications may be used by professionals when necessary, but research focuses on strategies that minimize impact on beneficial insects and complement biological control efforts.