Scientific name: Halyomorpha halys Stål
Native range: Asia
In Minnesota, brown marmorated stink bug has only been detected in a few spots spread throughout the state. One small overwintering population has been detected, but the insect is not yet considered to be established. It takes about 5–10 years for it to go from a household nuisance to significant plant pest.
Across North America, brown marmorated stink bug has been found in 42 states and two Canadian provinces (Ontario and Quebec). It is causing severe agriculture problems in six states and nuisance problems in 19 others.
Adult brown marmorated stink bugs are ½ -inch-long shield-shaped insects from the true bug order (Hemiptera). They have long piercing-sucking mouthparts held under the body between the legs, and often release an odor when disturbed or crushed. The name 'brown marmorated stink bug' describes their appearance: they are brown with a marmorated (marble-patterned) exterior. Nymphs (young) are more colorful, with red and orange markings.
Other key features to look for when identifying adult brown marmorated stink bugs are the rounded 'shoulders', the alternating dark-and-light pattern along the edges of the abdomen, the dark-colored antennae with light-colored bands, and the green and gold flecks on the underside of their 'shoulders'.
Brown marmorated stink bug completes one generation per year in Minnesota and overwinters as adults in a hibernation-like state in woodlots, households, sheds and garages. Adults emerge in March and April and produce offspring in June. Females deposit eggs in clusters of approximately 25. Nymphs are present and active during the summer months. There are approximately five nymphal stages. Adults feed until September and October, when populations typically peak, and then seek overwintering sites. It takes approximately 538 degree days for eggs to develop into adults.
There are many stink bugs in Minnesota, most of which can be easily confused with brown marmorated stink bug. Native brown stink bugs (Euschistus spp.) are especially similar to brown marmorated stink bug. Other species commonly mistaken for brown marmorated stink bug that are not in the stink bug family (Pentatomidae) include: the western conifer seed bug (Leptoglossus occidentalis), the squash bug (Anasa tristis), and the box elder bug (Boisea trivittata).
Host plants - Brown marmorated stink bug has a wide range of host plants. Over 300 plant species in agricultural, horticultural, and natural settings are susceptible to attack. It has been observed on hundreds of tree species in the mid-Atlantic states but it is unclear what species will be preferred in Minnesota. Brown marmorated stink bug tends to congregate on tall plants and trees rather than plants lower to the ground. After emerging in spring, adults are found on almost any plant exposed to the sun. Plants located near overwintering sites are a common place to find adult insects early in the season. Plants with fruits, buds, and pods; in places such as orchards; tend to attract this insect more often than plants without those reproductive structures.
Possible target crops in Minnesota include: apple, grape, soybean and other vegetables commonly grown in private and community gardens.
Impact - Brown marmorated stink bug prefers fruits as a food-source, but will feed on nearly all plant parts. Injury caused by feeding produces small necrotic areas on the outer surface of fruits and leaves. In apples, feeding by this insect creates cork-like dead spots that can become sunken and render the fruit unsuitable for market. All damage done is superficial and the fruit is safe to eat, however not preferred by consumers. Most damaged fruit is sent off for processing. Significant injury caused by brown marmorated stink bug in orchards can result in large economic losses. In 2010, the apple industry alone estimated losses of about $37 million because of brown marmorated stink bug damage in the mid-Atlantic region.
Due to unpleasant odor, large size, and sheer numbers, brown marmorated stink bug can be a nasty home invader as well. Large numbers will congregate and invade buildings in search of overwintering sites.
Brown marmorated stink bug has only been detected in Minnesota and is not a plant pest. Therefore, the best way to prevent invasion is to detect where the insects are, and determine if populations are establishing. If you observe an insect that looks like brown marmorated stink bug please take a picture or sample and contact the MDA’s Arrest the Pest.
Although brown marmorated stink bug is slowly spreading in affected states by flying from crop-to-crop, it is also a hitchhiker, and individuals can quickly be transported into new states on vehicles, trailers, RV’s, or by moving infested materials (e.g. woodsheds). To slow this spread, please inspect your vehicles and any accompanying equipment, and remove any suspect insects, before leaving heavily infested states, such as Pennsylvania, Virginia, Maryland, Delaware, New Jersey, or West Virginia.
In mid-Atlantic states, where brown marmorated stink bug is a severe problem, an integrated pest management approach is being employed that uses a combination of monitoring, insecticide use, and other natural means. Research is ongoing on the development of biocontrol throughout the country.
If you think you have an infestation of brown marmorated stink bug, please visit our Arrest the Pest page to report the finding to the MDA.
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The Minnesota Department of Agriculture (MDA) has a joint project with the University of Minnesota (U of M) that seeks to install a framework for monitoring brown marmorated stink bug within Minnesota, identify developing problem areas and research potential biocontrol. The MDA conducted a statewide survey for brown marmorated stink bug in 2014 using ground pyramid traps baited with an aggregate pheromone for this insect. This survey will be repeated with some modifications in 2015. The survey yielded a single adult brown marmorated stink bug catch, although nymphs and adults were observed at a known site throughout the season. The U of M is evaluating a wasp that parasitizes brown marmorated stink bug in its native range for cold hardiness, to see if it can survive Minnesota’s cold winters.
Minnesota Department of Agriculture (MDA), 625 Robert Street N, St. Paul, MN 55155-2538, firstname.lastname@example.org