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Stink BugsHalyomorpha halys
Stink Bug Identification
Triangular or shield
Found in the eastern half of the U.S., as well as California, Oregon, Washington, Arizona, New Mexico and Texas
What Do Stink Bugs Look Like
Stink bugs are described in several different ways. They are characterized as both “large, oval-shaped insects” and “shield-shaped insects.” Adult stink bugs can reach almost 2 cm in length. They are nearly as wide as they are long. Their legs extend from the sides, so this makes the adult bugs appear even larger. The brown marmorated stink bug is a brownish stink bug. It has lighter bands on the antennae and darker bands on the wings.
Adult stink bugs are good fliers and fold their wings on top of their body when they land. Nymphs do not have fully developed wings. The wings appear when the nymph becomes an adult. Fully developed wings are a way to identify adult stink bugs.
Immature stink bugs, called nymphs, are very tiny when they hatch from their eggs. Nymphs of the brown marmorated stink bug are yellow and red. As they grow, the yellow fades to white. They have bright red eyes during the nymph stage of their life cycle. The nymphs molt or shed their skin five times. Each time a stink bug nymph molts, it becomes larger. By the last molt, the nymphs are almost as large as adult stink bugs.
Signs of an Infestation
Homeowners often find stink bugs inside during the late summer months and autumn when temperatures outside start to drop. Finding large numbers of live or dead stink bugs is a telltale sign of an infestation. Stink bugs will turn up on sunny sides of homes where they warm themselves. Growers often detect an infestation by the damage they cause to their crops.
If an infestation has developed inside the home or building, contact a licensed stink bug control professional to evaluate and assess the severity problem and help to identify the access points for this invasive species.
Stink Bug Photos
Stink Bug Infestation
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Stink Bug Odor
Stink bugs get their name from the unpleasant odor they produce when they are threatened. It is thought that this odor helps protect the bugs against predators. The stink bugs produce the smelly chemical in a gland on their abdomen. Some species can actually spray the chemical several inches. The smell has often been compared to strong herbs and spices like cilantro and coriander.
Interestingly, the composition of the odor is comprised of chemicals commonly used as food additives and is present in cilantro. This smell can linger for hours so, if possible, try to avoid stink bugs or carefully sweep or vacuum them up if they have entered your house.
Stink Bug Education
In general, adult stink bugs feed on fruits and nymphs feed on leaves, stems and fruit. The life cycle of brown marmorated stink bugs generally involves mating, reproducing and feeding from spring to late fall. Upon the onset of cold weather, stink bugs seek shelter to spend the winter in a dormant phase known as diapause.
Stink bugs search for overwintering sites in late fall before the weather conditions drastically change, leading them to seek out shelter in homes and other man-made buildings. They spend the winter hiding inside homes or buildings, usually in the walls, attic or crawl space. However, entering into diapause may not be the complete end to their season of activity. If the weather warms up for a long enough period of time, indoor overwintering stink bugs might be misled into thinking it is time to exit their diapause period and become active again. Stink bugs reemerge in early spring and become active. During warmer months, these pests can usually be found congregating on the sides of buildings.
Brown marmorated stink bugs mate and create up to 3 generations per year depending on their habitat. Cooler zones see one generation per year, while warmer areas are likely to see 2-3. Female stink bugs typically lay 20 to 30 eggs. Egg laying generally occurs from May through August. The eggs are light green, barrel-shaped, and are attached side-by-side on the underside of the host plant’s leaves in a mass. Eggs hatch four to five days later and the nymphs will begin to feed. They undergo a series of molts until they become adults by fall.
Native to Asia, stink bugs were accidentally introduced into the United States sometime during the late 1990s. As an invasive species, they do not have any natural predators and can therefore rapidly spread. Stink bugs have become established in many areas of the country, posing a particular threat to the agricultural industry as they destroy crops. Stink bugs can damage ornamental plants, fruit trees, and gardens, but they are more of a nuisance than a threat to people. They do not cause structural damage or spread disease.
The brown marmorated stink bug cannot sting and is not likely to bite, but care should be exercised when handling them to deter these pests from releasing their well-known and unpleasant odor. The stink bug’s mouthparts are grouped in the piercing/sucking category, but they do not use blood as a food source like mosquitoes, biting flies and bed bugs. Their mouths are not structured in a way that enables them to bite through human skin. Most species of stink bugs feed on plants. They suck the juice from leaves, stems and roots of plants. They attack everything from ornamental plants to weeds. The insects pierce the skin of the plant and extract the juice inside.