Status of the brown marmorated stink bug
The brown marmorated stink bug (BMSB), Halymorpha halys, was detected in soybean fields in several counties of western Kentucky between August and September 2020. This insect is widely distributed and has been established in eastern Kentucky since 2013. However, single BMSB specimens were reported sporadically in several counties in western counties since 2014, which might have been the result of the “hitchhiking behavior” of this insect – carried in transportation vehicles or shipping packages. Just this weekend while I was returning from Lexington, I found a BMSB travelling with me. This specimen was well-hidden between the trunk-top and the weather strip of my automobile’s trunk (Figure 1).
Brown marmorated stink bug might had been present in soybean fields but in undetectable levels. Monitoring for stink bugs intensively in soybeans since 2016 produced no findings up until this year. Due to unknown conditions, this insect was not well-established, populations were low, and furthermore, they have not been noticed moving into human dwellings in western Kentucky.
Overwintering brown marmorated stink bugs and their management
In addition to the issues caused by the feeding of BMSB in vegetables and fruit (tomatoes, peppers, apples, peaches, sweet corn, etc.), and field crops (corn and soybeans); this species tends to aggregate in September/October and then move into human-build structures to overwinter (Figure 2). Personally, I have observed this behavior for the first time since living in Western Kentucky. I have been capturing 6 to 10 BMSB per day since last Tuesday (October 6,2020) in the screens of my home.
Most eastern Kentuckians are aware of BMSB’s overwinter behavior (as are people from many other states where this pest has been occurring for a couple of years); however, the population of western Kentucky needs to learn about some valuable safeguards to avoid an explosive invasion of this obnoxious and foul-smelling insect.
The first step is to seal or repair cracks and crevices in doors, windows or screens to prevent the entrance of BMSB. This should be completed during September or October, months when BMSB fly from fields or tree lines near houses looking for well-sheltered overwintering spots. This behavior is a response to decreasing day length and temperature. Buildings in poor condition with gaps, barns, and garages are preferred sites for infestation. Brown marmorated stink bugs may enter these types of units in great numbers (Figure 3). In nature, BMSB can overwinter on standing dead trees with loose, thick bark (such as oak and locust) or rocky ledges. This species does not overwinter in shrubs, mulch or leaf litter, which are generally too moist for their survival and where native stink bugs overwinter.
If heavy infestations occur, insecticides might be the best choice. However, householders may want to hire a professional pest control agent or check for valuable advice from a county Extension agent since the most effective insecticides require special certification for their use. Check ENTFACT-654 for broader information about how to manage this pest.
- Stink Bug Infestation of Dwellings ENTFACT-654
By Raul T. Villanueva, Entomology Extension Specialist