Written by Adrian Marshall, USDA Agricultural Research Service, 16 June 2026. Edited by Tianna DuPont.
Western box elder bugs and stink bugs feed on the protein packed seed pods of plants in the uncultivated shrub-steppe and riparian habitats surrounding most eastern Washington orchards. As the summer progresses some of these plants begin to senesce and tree fruit begins to mature. Adults and large nymphs will move from the surrounding habitat into the orchards to feed on the fruit causing dimpling and corking damage making it unmarketable.
Many species of stink bug, primarily in the genera Chlorochroa, Thyanta, and Euschistus, have been found in eastern Washington tree fruit orchards and will feed on a wide variety of plants including but not limited to mullein, lupins, bitterbrush, Oregon grape, and currants. The western box elder bug primarily feeds on boxelder trees, but will also feed on other trees such as maple, ash, and fruit trees. Both stink bugs and box elder bugs have piercing-sucking mouthparts and cause nearly identical damage to fruit.
Management Strategies
Stink Bugs
Studies conducted at WSU tree fruit research center found that stink bugs will move between the natural vegetation and the orchard beginning in June and then continue throughout the summer, so timing treatments earlier in the summer can help improve protection. They also showed that a physical barrier such as a netted fence can prevent stink bugs from flying into the orchard (Marshall and Beers 2024). Insecticide formulations and timings for stink bug management can be found at the WSU crop protection guide.
Box Elder Bug
The western boxelder bug has historically been a minor and sporadic pest; however, in recent years there have been many reports of pear growers experiencing economically significant damage from boxelder bug. Insecticide efficacy data is lacking and the primary recommendation is alternate host removal such as removing female boxelder, maple and ash trees from the surrounding landscape.
Contact
Adrian Marshall
USDA-ARS Temperate Tree Fruit and Vegetable Research Unit
adrian.marshall@usda.gov
509-860-6752
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