Brown marmorated stink bug

Halyomorpha halys

85 host plants

Last updated

You will spot brown shield-shaped insects about 1/2 inch long on fruit, leaves, and stems during late summer and fall. These bugs pierce plant tissue with straw-like mouthparts and suck juices, causing dimpling, distortion, and decay in fruit or seeds. Look for them on serviceberry, hawthorn, mahonia in warm microclimates.

Remove and destroy infested fruit or seed heads before bugs disperse to overwintering sites. Knock bugs off plants early morning when sluggish into soapy water. Protect high-value crops with row covers before bugs appear. Encourage parasitoid wasps by reducing broad-spectrum insecticide use. Organic spinosad provides control; chemical treatment rarely justified for ornamentals.

Quick Reference

Order
Hemiptera
Type
sucking-insect
Host Plants
85
Peak Activity
Mid-June through September in western WA. Adults emerge April-May; egg laying...
Damage Severity
growth-reducing

Monitoring & Action

How to Monitor

Pheromone-baited traps using clear double-sided sticky panels with aggregation pheromone and MDT (methyl (2E,4E,6Z)-decatrienoate) synergist are the standard monitoring tool. Supplement with beating tray sampling (hold tray beneath branches, strike branch sharply) and visual searches for egg masses on leaf undersides. Scout early morning when bugs are less active. source: UC IPM, stopBMSB.org

What Damage Looks Like

Piercing-sucking mouthparts inject digestive enzymes into plant tissue and extract fluids. On pome fruits (apple, pear), feeding causes catfacing: sunken, dimpled areas on the fruit surface with corky, pithy or mealy tissue underneath that may not appear until cold storage. On stone fruits (peach, cherry, plum), damage appears as gumming, cat-facing, and sunken areas. On filberts, feeding produces empty shells or corky, damaged nutmeat. On blueberries, feeding creates sunken areas that may develop secondary rot. On tomatoes, pinprick-like pale spots appear on fruit surfaces, often followed by secondary rot organisms. On beans, damage appears as warty or pimple-like growths on pod surfaces, with whitish or brown spots inside pods and shrunken seeds. source: WSU HortSense

Cultural Controls

  • Hand-pick and destroy egg masses and groups of young nymphs WSU HortSense
  • Net-sweeping, plant vacuuming, or shaking infested plants over a drop cloth to collect adults and nymphs WSU HortSense
  • Apply floating row covers after pollination to exclude stink bugs WSU HortSense
  • Remove alternate hosts, especially tree of heaven (Ailanthus altissima) UC IPM
  • Seal structure entry points before fall dispersal WSU Extension FS079E
  • Maintain weed-free groundcover around crops; avoid mowing when bugs are present on ground-level hosts WSU HortSense

Host Plants (85)

Arbutus unedo Strawberry Tree, Killarney Strawberry Tree, Madroño Asimina triloba Common Pawpaw Custard Apple Berberis aquifolium Oregon Grape, Oregon Grape Holly, Tall Oregon Grape Berberis pinnata California Barberry, California Holly Grape Betula lenta Sweet Birch, Cherry Birch, Black Birch Ceratonia siliqua Carob St. John's Bread Locust, Bean Cornus capitata Evergreen Dogwood, Bentham's Cornel, Himalayan Strawberry Tree Corylus americana American Hazel, American Filbert Corylus avellana Common Filbert Dermatophyllum secundiflorum Mescal Bean Texas Mountain Laurel, Frijolito Eucalyptus cinerea Silver Dollar Eucalyptus, Silver Dollar Gum Argyle Apple Euonymus americanus American Euonymus, Hearts-a-Burstin', Strawberry Bush Fragaria chiloensis Beach Strawberry Sand Strawberry, Chilean Strawberry Magnolia acuminata Cucumber Magnolia, Cucumbertree Magnolia, Mountain Magnolia Malus 'Indian Magic' Indian Magic Crabapple Malus 'Prairifire' Prairifire Crabapple Malus 'Snowdrift' Snowdrift Crabapple Malus atrosanguinea Carmine Crabapple Malus brandywine Brandywine Crabapple Malus floribunda Japanese Flowering Crabapple Malus fusca Pacific Crabapple Malus hupehensis Tea Crabapple Malus pumila Apple Malus robusta Cherry, Crabapple Malus sargentii Sargent Crabapple, Pigmy Crabapple Malus transitoria Transitoria Crabapple Microcachrys tetragona Creeping Pine, Creeping Strawberry Pine Prunus americana Wild Plum American (Red) Plum August Plum, Goose Plum Prunus armeniaca Apricot Prunus avium Sweet Cherry Prunus besseyi Sand Cherry, Western Sand Cherry Prunus blireiana Blireiana Plum Prunus caroliniana Carolina Cherrylaurel American Cherrylaurel Prunus cascade Prunus cascade Prunus cerasifera Cherry, Plum Prunus cistena Purpleleaf Sandcherry Redleaf Sandcherry Cistena Sandcherry Cistena Plum Prunus dream Prunus dream Prunus emarginata Bitter Cherry, Wild Cherry, Quinine Cherry Prunus first Prunus first Prunus fruticosa Steppe Cherry, European Dwarf Ground Cherry, Mongolian Cherry Prunus glandulosa Dwarf Flowering Almond Prunus ilicifolia Hollyleaf Cherry, Holly-leaved Cherry Prunus laurocerasus Cherry, Laurel Prunus lusitanica Portugal Laurel Prunus maackii Amur Chokecherry Amur Cherry, Manchurian Cherry Prunus mume Japanese Flowering Apricot Prunus newport Newport Flowering Plum Prunus okame Okame Flowering Cherry Prunus padus European Birdcherry Common Birdcherry Prunus prostrata Rock Cherry, Mountain Cherry Prunus sargentii Sargent Cherry, Sargent's Cherry Prunus serotina Black Cherry, Rum Cherry Prunus serrula Birchbark Cherry, Paperbark Cherry, Tibetan Cherry Prunus serrulata Japanese Flowering Cherry Prunus snow Prunus snow Prunus subcordata Klamath Plum, Sierra Plum, Pacific Plum Prunus subhirtella Higan Cherry Prunus subhirtella var. autumnalis Autumn Flowering Higan Cherry Prunus tai Prunus tai Prunus virginiana Prunus virginiana Prunus virginiana var. demissa Western Chokecherry Prunus virginiana var. virginiana Common Chokecherry, Eastern Chokecherry Prunus yedoensis Yoshino Cherry, Somei-yoshino Cherry, Tokyo Cherry Pyrus communis Common Pear Pyrus fauriei Pyrus fauriei Pyrus salicifolia Pyrus salicifolia Rosa rugosa Rugosa Rose, Beach Tomato, Sea Tomato Rubus allegheniensis Allegheny Blackberry Rubus armeniacus Himalayan Blackberry Armenian Blackberry Rubus calycinoides Crinkle-leaf Creeper Creeping Raspberry Yü-shan raspberry Rubus dicolor Himalayan Blackberry Armenian Blackberry Rubus laciniatus Evergreen Blackberry Cutleaf Blackberry Rubus leucodermis Blackcap, Western Raspberry Rubus odoratus Flowering Raspberry Purple-flowering Raspberry Rubus tricolor Creeping Bramble Korean Raspberry Rubus ursinus Trailing Blackberry Western Blackberry California Blackberry Dewberry Sambucus nigra subsp. cerulea Blue Elderberry, Blueberry, Elder Sophora secundiflora Mescal Bean Texas Mountain Laurel, Frijolito Vaccinium angustifolium Lowbush Blueberry Vaccinium corymbosum Highbush Blueberry Vaccinium crassifolium Creeping Blueberry, Thick-leaved Whortlberry Vaccinium moupinense Himalayan Blueberry Vaccinium ovalifolium Oval-leaf Blueberry Vaccinium sikkimense Sikkim Blueberry Waldsteinia fragarioides Barren Strawberry

BMSB established and expanding across western Washington. Documented in 21+ counties, with the majority of detections along the I-5 corridor. Populations have been building significantly since approximately 2023. The maritime climate likely limits BMSB to one full generation per year in the Puget Sound lowlands, compared to two in warmer inland valleys. source: WA Invasive Species Council, WSU Extension

— Chris Welch, ISA Certified Arborist

Sources & References

Primary: WSU HortSense

Data Maturity
Structured Multiple sources. Expert review underway.