It was first confirmed in the Midtown and downtown areas of Sacramento earlier this year.
Now it has spread to Yuba City, about 50 miles to the north, according to an Extension newsletter.
Because the California Department of Food and Agriculture classifies it as a B pest, no eradication is planned.
It is estimated the stink bug may have been in the Sacramento area for two to three years, possibly longer.
They are strong fliers and can cover up to 1/2 mile. Because of this, University of California Extension farm advisers recommend growers and pest control adviers be on the lookout for these true bugs.
Several pheromone traps are available, but most are not effective at catching the bug until populations are high.
Control of BMSB is challenging, since few products are effective. Using pyrethroids, organophosphates and neonicotinoids may distrupt integrated pest management programs, too.
Even if you treat a field, they can quickly migrate in from nearby areas.
They feed on a wide variety of crops, ranging from pome and stone fruit to peppers, tomatoes and even corn.
For more information, including identification tips and photos, visit UC IPM.