Brown marmorated stink bug,
Adults of brown marmorated stink bug are 14-17 mm (0.5-0.75 inches) long. 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 range in size from 2.5-12 mm (0.1-0.5 inches) and develop through five instar stages. Young nymphs are yellow, red, and black with strong white bands on their legs. Older nymphs more closely resemble adults.
Brown marmorated stink bugs lay white or pale green eggs on the underside of leaves in clusters of 20-30, and adults will lay multiple clusters of eggs over an extended period.
- The brown marmorated stink bug is an invasive insect introduced from Asia. It is now found throughout the United States.
- Brown marmorated stink bug should not be confused with many species of native stink bug in Colorado. The presence of two white bands on each antenna can be used to distinguish brown marmorated stink bug from other members of this family.
- Brown marmorated stink bugs are pests of fruit trees, vegetables, and field crops. They tend to migrate into agricultural crops from overwintering locations. Infestations in adjacent crops can also be a source after the area containing the infestation is harvested.
- 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.
Brown marmorated stink bug adult. 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
Life history and habits
First instars feed on the remaining egg contents after emerging. The number of generations per year is temperature dependent, with one to three generations per year in states with variable climates.
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.
A single fruit can be under attack by multiple adults when brown marmorated stink bug densities are high. Both adults and nymphs inject enzymes into plant tissues when they feed. Feeding on fruit results in oozing wounds and turns flesh under the skin hard and pithy. Feeding on younger fruits can cause discoloration, disfiguration, and pockmarks as the fruits grow.
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.
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.
Trap catches tend to be highest later in the summer. Treatment thresholds have not yet been established for this pest. There are several trap options available, and in some cases the addition of an insecticide strip on the trap surface can improve control since the stink bugs do not always enter traps. For more information on traps, consult the University of California guidelines.
There are predatory arthropods that will feed on brown marmorated stink bug, including assassin bugs, praying mantises, spiders, and certain predatory wasps. However, these natural enemies do not provide adequate control in commercial crops.
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, effective control is accomplished by spraying only the edges of orchards. Generally, chemical control tends to be most effective when younger instars are targeted. For more information on chemical control of brown marmorated stink bug, consult the University of California guidelines.
EPA. 2022. Brown Marmorated Stink Bug. United States Environmental Protection Agency. Available https://www.epa.gov/safepestcontrol/brown-marmorated-stink-bug#agriculture
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
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.
University of Maryland. 2021. Brown Marmorated Stink Bug. University of Maryland – Extension. Available https://extension.umd.edu/resource/brown-marmorated-stink-bug