Brown marmorated stink bug,
Halyomorpha halys
Order: Hemiptera
Family: Pentatomidae
Description
The brown marmorated stink bug (Halyomorpha halys) is native to Asia and an invasive species in North America. It is now found throughout the United States, although its relative impact on crops and its status as a house pest varies in different regions. Adults of brown marmorated stink bug are 14-17 mm (0.5-0.75 inches) long and have marbled gray, brown, and black bodies that camouflage well with the surrounding environment. The undersides of adults are light gray to off-white, and they have a pentagonal body shape. Key identifying features include two white bands on each of the antennae, dark bands on the tips of the forewings, and marbled brown legs with very faint white bands. Nymphs lack developed wings and range in size from 2.5-12 mm (0.1-0.5 inches). The nymphs change color as they develop, with different combinations of yellow, red, and black. They have red eyes and prominent white bands on their legs. Older nymphs more closely resemble adults than younger nymphs. The barrel-shaped eggs are white or pale green and measure 1.6 mm (1/16 inch) long. The black head of the developing nymph can be seen through the egg near hatching.
Quick Facts
- Brown marmorated stink bugs are pests of fruiting plants, vegetables, and field crops. They tend to migrate into agricultural crops from overwintering locations, and infestations in adjacent crops can also be a source after harvest. This pest is considered a nuisance when they aggregate indoors in large numbers.
- Brown marmorated stink bug is characterized by two white bands on each antenna. This morphological feature can be used to distinguish this species from native stink bug species inhabiting Colorado.
- The odorant released by stink bugs is stored in scent glands on the underside of the thorax and back of the abdomen. The odors are released and produce a concentrated cilantro-like smell when the stink bug is killed or disturbed.
- Monitoring is important for effective management, which primarily involves applications of insecticides.
Brown marmorated stink bug adult. Note the white bands on the antennae. Brown marmorated stink bugs are an invasive insect pest from Asia and are considered pests of fruit trees, row crops, and are often a nuisance pest invading homes in cooler months. Image credit: Susan Ellis, Bugwood.org
Egg mass of brown marmorated stink bug. Image credit: Susan Ellis, Bugwood.org
Newly hatched egg mass. Image credit: Gary Bernon, USDA APHIS, Bugwood.org
Different instars of brown marmorated stinkbug. The dark red nymph is the first instar. The light red nymph is a second instar that recently molted, and the remaining four nymphs are also second instars that have not recently molted. Image credit: Gary Bernon, USDA APHIS, Bugwood.org
Brown marmorated stink bugs on peach. Image credit: Gary Bernon, USDA APHIS, Bugwood.org
Astata occidentalis attacking a stink bug. Image credit: Howard Ensign Evans, Colorado State University, Bugwood.org
Life history and habits
Adults overwinter in buildings or under the bark of large trees. If diverse fruits are grown throughout the season, these insects can also overwinter within crevices of tree trunks and branches. Activity resumes the following spring as the adults begin feeding and mating. Adults are strong flyers that can readily disperse and colonize new areas. They tend to congregate on host plants and buildings, which is mediated by an aggregation pheromone. About two weeks later, eggs are laid on the underside of leaves in clusters of 20-30. Females will lay multiple clusters of eggs over an extended period, producing up to 400 eggs in a single growing season. When disturbed, this pest secretes a defensive compound that produces an unpleasant odor. Newly hatched nymphs feed on the remaining egg contents after emerging and are typically confined to the natal host plant since they cannot fly. The nymphs develop through five instars. In the late fall, adults migrate to overwintering sites.
This pest can feed on over 100 species of plants in North America. Some examples of susceptible fruits include pear (Pyrus spp.), cranberry (Vaccinium oxycoccos), blueberry (Vaccinium spp.), plum (Prunus domestica), apple (Malus spp.), chokecherry (Prunus virginiana) grape (Vitis vinifera), fig (Ficus carica), and citrus fruits (Citrus spp.). The tree of heaven (Ailanthus altissima) can host large numbers of brown marmorated stink bugs over the growing season and is a useful indicator when conducting visual inspections. The number of generations per year is temperature dependent, with one to three generations per year in states with variable climates.
Injury
All stink bugs have piercing-sucking mouthparts for extracting fluids from plant tissues, and it is not possible to distinguish the injuries inflicted by brown marmorated stink bug from that of other stink bugs. Both adults and nymphs inject enzymes into plant tissues when they feed. Feeding on fruit results in oozing sap and turns flesh under the skin hard and pithy. Feeding on younger fruits can cause discoloration, disfiguration, and pockmarks as the fruits grow. A single fruit can be under attack by multiple adults when brown marmorated stink bug densities are high. The release of noxious defensive compounds by brown marmorated stink bug can taint the juice and wine produced from the grapes of infested vineyards.
Early season damage is especially problematic on peaches and nectarines. However, in other fruit trees damage tends to be most severe on late-maturing fruit when stink bug densities are higher. This pest can also attack other parts of the plant such as buds, stems, leaves, branches, small tree trunks, and seed pods. Feeding on leaves causes stippling areas around feeding sites that are roughly 3 mm (1/8 inch) in diameter. These feeding wounds can also lead to secondary infection by plant diseases. In corn, the bugs feed on kernels and cause them to shrivel as fluids are extracted. A similar feeding behavior is observed in soybean, in which the stink bugs pierce bean pods and extract fluids from the seeds. Injured soybean plants stay green for longer and don’t senesce when other plants in the field do.
Monitoring
Traps, beat sheet sampling, and inspecting plants for adults, nymphs, egg masses, and fluids oozing out of damaged fruit can help determine whether the pest is present. There are several trap options available, such as 4-foot pyramid traps which contain an inverted plastic collection container with a conical entry opening at the top. Generally, capture rates of brown marmorated stink bug tend to be highest later in the summer. These traps are baited with lures that emit volatile compounds which attract insects within a radius of 30.5 meters (100 foot). Two different compounds, the aggregation pheromone and methyl decatrienoate, can be purchased in lures separately or in combination and can aid in early detection. In traps with a collection container, an insecticide strip should be included to kill the captured stink bugs, and the addition of an insecticide strip on the trap surface can improve control since stink bugs sometimes remain on the surface or general vicinity of traps without entering the collection container. To maintain efficacy, the insecticide strip should be replaced according to the manufacturer’s guidelines.
Beat sheet sampling is quicker than conducting visual inspections and involves beating the branches of a host plant over a beat sheet or tray to dislodge insects. Sampling should be done early in the morning since adults will readily fly away when disturbed during warmer weather. When inspecting plants, foliage and fruit should be examined for adults, nymphs, egg masses, and spots of exuding plant fluids. Trees on the periphery of orchards and nearby hosts such as the tree of heaven should be prioritized during visual inspections. Beat sheet sampling and visual inspections are especially important for early detection when this pest is found nearby in urban areas. When eggs or young nymphs are found, insecticides that target the vulnerable nymph stages can be effective.
Treatment thresholds have not yet been established for this pest, although experiments conducted on the East Coast suggest that a threshold of ten brown marmorated stink bugs per trap is a good treatment threshold in apple and peach orchards. For more information on traps, visit the University of California guidelines.
Cultural control
In commercial production systems, establishing a border of trap crops can help reduce the density of stink bugs in the cash crop. In eastern states where the brown marmorated stink bug is a significant agricultural pest, effective trap cropping has been demonstrated with sorghum (Sorghum spp.), millet (Pennisetum glaucum), buckwheat (Fagopyrum esculentum), and sunflower (Helianthus spp.).
Biological control
There are predatory arthropods that will feed on brown marmorated stink bug, including assassin bugs (Hemiptera: Reduviidae), praying mantises (Mantodea: Mantidae), spiders, and certain predatory wasps, namely Astata spp. (Hymenoptera: Astatidae). The samurai wasp, Trissolcus japonicus (Hymenoptera: Scelionidae), is a specialist parasitoid of the brown marmorated stink bug. Wild populations of the samurai wasp have recently been found in Maryland where this brown marmorated stink bug is a significant agricultural pest. However, the impact of the samurai wasp on the pest population and native stink bugs has not yet been described.
The entomopathogenic fungus Beauviera bassiana strain GHA is highly effective against immatures and adults of brown marmorated stink bug in greenhouse settings. Research suggests that potential management strategies using B. bassiana should target the immatures, which are more susceptible to infection than adults. However, more work is needed to determine whether formulations of B. bassiana can suppress populations of this pest in the field.
Chemical control
In regions where brown marmorated stink bug is problematic, alternate-row treatments on fruit trees are conducted from late May and continue through the growing season until harvest. Several chemicals are used, sometimes in combination. In some instances, applying insecticides to crop borders is effective and has been shown to reduce insecticide use by as much as 85%. It is worth noting that insecticides appear to vary in their toxicity toward brown marmorated stink bug at different times of the growing season. Generally, chemical control tends to be most effective when young nymphs are targeted, and the insecticide is applied directly to the insect. However, the residual activity of insecticides diminishes after several days as more adults migrate into the treated area. For this reason, weekly applications are made in the orchards of Mid-Atlantic states. For more information on chemical control of brown marmorated stink bug, visit the University of California and Utah State University guidelines.
CSU Extension Fact Sheet
Download or view the CSU Extension’s PDF fact sheet for your reference.
References
EPA. 2022. Brown Marmorated Stink Bug. United States Environmental Protection Agency. Available https://www.epa.gov/safepestcontrol/brown-marmorated-stink-bug#agriculture
Holthouse, M., D. Alston, L. Spears, and E. Petrizzo. 2017. Brown Marmorated Stink Bug. Utah State University – Extension. Available https://extension.usu.edu/pests/research/brown-marmorated-stink-bug
Ingels, C. 2017. Brown Marmorated Stink Bug Provisional Guidelines for Peach. University of California – Agriculture & Natural Resources. Available http://ipm.ucanr.edu/PMG/r602301711.html
LaForest, J. 2015. Halyomorpha halys. Wiki.Bugwood.Org. Available https://wiki.bugwood.org/Halyomorpha_halys
Mesa County. (n.d.). Brown Marmorated Stink Bug. Mesa County – Pest Alert. Available https://www.mesacounty.us/pest/ugvpcd/pest-alert/brown-marmorated-stink-bug/#:~:text=Brown%20marmorated%20stink%20bug%20is,which%20can%20become%20agricultural%20pests.
StopBSMB.org. 2021. State-by-State. United States Department of Agriculture. Available https://www.stopbmsb.org/where-is-bmsb/state-by-state/
University of Maryland. 2021. Brown Marmorated Stink Bug. University of Maryland – Extension. Available https://extension.umd.edu/resource/brown-marmorated-stink-bug
Parker, B., M. Skinner, S. Gouli, V. Gouli, and J. Kim. 2015. Virulence of BotaniGard® to Second Instar Brown Marmorated Stink Bug, Halyomorpha halys (Stål) (Heteroptera: Pentatomidae). Insects. 6: 319-324. Available https://mdpi-res.com/insects/insects-06-00319/article_deploy/insects-06-00319.pdf?version=1428569438