They're brownish gray, shaped like a shield and smell like cilantro. Or rotting fruit. Or pine sap. Depends on who you ask.

Brown marmorated stink bugs were found last month at the residence of a couple who had moved to Nampa from Maryland. The upper East Coast has been inundated with stink bugs in recent years. The bugs arrived in Pennsylvania in the 1990s and spread to 34 states, including Idaho's neighbors to the west.

But Idaho isn't infested yet. The adult bugs in Nampa are the only ones to appear in Idaho so far, said state entomologist Jodie Ellis.

The discovery is an "opportunity for people to become aware of the potential problem," she said.

The bugs are a nuisance in the home. They hide in windows, sheds, attics or outside in wheel wells. "Back in their native range [in Asia], they overwinter in caves," Ellis said. "Anything that resembles a cave is fair game."

They also hang out in groups. The social bugs emit "aggregation pheromones" to attract friends and mates, especially when they find something tasty to eat, Ellis said.

Infestations can be a serious problem for farmers with crops or trees. The bugs eat anything with skin, Ellis said. Peaches, apples, corn, tomatoes, grapes, peppers and even soybeans are in danger of being devoured.

So far, the insects have just one native predator in the U.S. That predator is humans.

But Ellis doesn't want Idahoans to kill the bugs if they see them. Instead, anyone who sees a shield-shaped bug with a brown or brownish gray mottled color should snap a picture or capture the specimen for experts to look at.

Ellis also recommends not using pesticides to prevent a home infestation. The easiest way to deal with the bugs is to keep them from entering homes, especially by sealing up cracks and other openings to the outdoors and using weather stripping on windows and doors.

"This is an interesting insect in that the public can really have a nice role in detecting where it is," Ellis said.

Report possible stink bugs by emailing a picture to Jodie.Ellis@agri.idaho.gov or calling 332-8627.