Brown Marmorated Stink Bug in Soybean
Crop Damage
The brown marmorated stink bug (Halyomorpha halys) is an invasive pest found throughout much of the United States and in five Canadian provinces. It causes significant damage to fruit and vegetable crops and is also a nuisance pest when it overwinters in homes and other buildings. Although the brown marmorated stink bug can be an important pest of soybeans, it typically accounts for less than 25% of the stink bug population in soybean fields in many states. Both nymphs and adults use their piercing-sucking mouthparts to feed on soybean leaves, stems, flowers, pods, and seeds. Brown marmorated stink bugs cause the greatest damage when they feed on pods and seeds, which can result in shriveled seeds and reduced seed size.
Pest Description
Young nymphs have brown heads with distinct orange and brown patterning on the abdomen. Older nymphs have gray bodies, spines on the edges of the shoulders (pronotum) near the head, and distinct white bands on the legs. Adults are approximately 5/8 inches long with brown-gray marbled colored bodies. Characteristic features include alternating black and white bands on the outer edges of the abdomen and antennae.
Brown marmorated stink bug nymph.
Adam Sisson, Iowa State University
Brown marmorated stink bug adult.
Adam Sisson, Iowa State University
Scouting and Management
There are no established scouting or management guidelines for stink bugs in the vegetative stages, as they rarely cause economic damage. States with a history of brown marmorated stink bugs may be at higher risk for spring soybean infestations as this species can overwinter in a variety of locations. In the spring, adults can move into nearby soybean fields. Spot treatments may be warranted if stink bugs are killing young soybean seedlings.
In general, most states recommend using a sweep net to monitor stink bug populations. Take 25 sweeps in 4 locations within the field. Larger fields may require additional sampling locations to obtain an accurate estimate of brown marmorated stink bug populations. Count the number of older nymphs and adults. Common insecticide treatment thresholds for stink bugs when using a sweep net are 9 stink bugs per 25 sweeps (40 stink bugs per 100 sweeps) for grain production fields and 5 stink bugs per 25 sweeps (20 stink bugs per 100 sweeps) in seed production fields.
Timing of scouting and treatment thresholds vary by state, so check with your local or state extension specialists on current scouting guidelines and thresholds. If other stink bugs are present, assess their impact before making management decisions. If treatment is warranted, it is important to consider the pre-harvest interval (PHI) when selecting the insecticide in late season applications.
Developed and reviewed by Carol Pilcher, Iowa State University and Robert Wright, University of Nebraska-Lincoln, with support from the United Soybean Board.
Brown marmorated stink bug nymph. Adam Sisson, Iowa State University.
Brown marmorated stink bug adult. Adam Sisson, Iowa State University.
Young brown marmorated stink bug nymphs. Note distinct orange and brown pattern on abdomens. David R Lance, USDA APHIS PPQ, Bugwood.org.
Brown marmorated stink bug nymph. The blue arrow indicates spines on the pronotum. The yellow arrow indicates the white bands on legs. David R Lance, USDA APHIS PPQ, Bugwood.org.
Brown marmorated stink bug adult. The black arrow indicates bands on edges of the abdomen. The blue arrow indicates bands on the antennae. Kristie Graham, USDA ARS, Bugwood.org.
Gallery images courtesy or Adam Sisson, Iowa State University; David R Lance, USDA APHIS PPQ, Bugwood.org; and Kristie Graham, USDA ARS, Bugwood.org.
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