The invasive pest spotlight focuses on emerging or potential invasive pests in California. In this issue we are covering the brown marmorated stink bug (BMSB). 

Brown marmorated stink bug facts 

BMSB can cause severe crop and garden losses and become a nuisance in and around homes and other buildings. They can get into buildings as they congregate in late summer and early fall when seeking safe overwintering sites. Once inside buildings BMSB may become a nuisance and emit an offensive odor if disturbed or crushed. In the spring, adults move from overwintering sites to host plants.  

Brown marmorated stink bugs are not harmful to people, houses, or pets. They do not bite, sting, suck blood, or spread mammalian diseases. They do not eat or bore into wood structures. Building occupants may become alarmed when the bugs enter the building and noisily fly about when lights are on. The ability of BMSB to hitchhike in vehicles and planes has allowed it to spread rapidly to new areas.  

The adult BMSB is a shield-shaped stink bug, about 5/8 inch long, and marbled brown. It can be distinguished from other similar stink bugs by the characteristics shown in Figure 1. 

What can you do? 

If you find a stink bug that you suspect might be a BMSB, place the bug in a container and carefully note where and when you collected it. Take the sealed container to your county agricultural commissioner or local UC Cooperative Extension office.  

For more information, read the BMSB Pest Alert on the UC IPM website ipm.ucanr.edu/pestalert/pabrownmarmorated.html.