Brown marmorated stink bug (BMSB)
BMSB, or Halyomorpha halys, is an important exotic pest insect in Oregon. It first arrived from Asia to the Portland area around 2004.
Farmers are most adversely affected by the pest. BMSB causes feeding damages on a huge spectrum of crops, including high-value specialty crops such as vegetables, hazelnuts, tree fruits, and small fruits. This can sometimes lead to economic loss. In other areas of the country, management of BMSB in agriculture has been very challenging and costly. Current management programs are heavily reliant on insecticides, and this has disrupted Integrated Pest Management (IPM) Programs that took years to develop.
Homes and businesses
In and around the home BMSB is a problem when it aggregates on structures where it overwinters, and it can become a continual winter annoyance to residents. Businesses are also targeted by BMSB for overwintering. It also has a negative effect on urban agriculture, including backyard gardens where it damages fruits and vegetables, sometimes causing complete crop destruction. Businesses are also targeted by BMSB for overwintering. In the urban environment, populations of the pest build up primarily on ornamental trees.
Where in Oregon is the pest?
BMSB is present in most Oregon counties throughout Oregon, but is most prevalent in the Willamette Valley, where BMSB can be locally abundant in urban, rural, and natural areas. In eastern and southern Oregon, BMSB has been largely restricted to urban areas where the greatest concentration and diversity of deciduous trees are found. BMSB can be locally abundant in urban, rural and natural areas.
Oregon offers BMSB a comfortable environment with abundant habitat and less pressure from natural enemies than it has in its native range of China, Korea, and Japan. However, that may be changing as its chief natural enemy in Asia was discovered in 2015 along the Oregon border in Vancouver, WA and in 2016 in Portland. The beneficial natural enemy has recently been found in Salem and Beaverton, and we expect that it will continue to spread. This natural enemy is a minute wasp (1-2 mm) called Trissolcus japonicus. Female wasps seek out the egg masses of BMSB, and they lay their own eggs inside. Instead of the BMSB eggs hatching with BMSB nymphs, they instead produce a new set of wasps. They don’t sting people but Aa clear sign of their activity are BMSB egg masses that darken to a black color. They don’t sting people.BMSB is present in counties throughout Oregon, but are most prevalent in the Willamette Valley where BMSB can be locally abundant in urban, rural and natural areas. In eastern and southern Oregon, BMSB has been largely restricted to urban areas where the greatest concentration and diversity of deciduous trees are found.
Why report BMSB?
While BMSB is no longer a new invader in western Oregon, and many of us have become desensitized to its constant presence around our homes and farms, the information provided in the reports is still very useful for us. The invasion of BMSB is still occurring in the eastern and southern part of Oregon and the reports help us document the invasion in those areas. We can gain useful insights about the pest in terms of its environmental associations and the timing of your observations. We are also very interested in reports of the pest attacking agricultural commodities, so that we can better direct our research and Extension efforts.
Hover your cursor over the map below to view sightings reported by county.
Key characters for identifying adult BMSB and distinguishing them from similar species are the distinct light bands on the dark antennae, smooth "shoulders", and abdominal margins that have a distinct banding pattern.
The samurai wasp (Trissolcus japonicus) is a parasitoid that attacks the eggs of the brown marmorated stink bug (BMSB), making it a potential candidate for managing this significant threat to commercial agriculture and residential gardens. More info here.