JoAnne Skelly: Invasion of the brown marmorated stink bug

Recently, I received a photo of a stink bug that I suspected was the invasive brown marmorated stink bug (BMSB). However, the insect seemed to be more charcoal gray than the typical brown color.

Insects can look very different not only at different stages of development but also when found in different areas.

Without being able to look at the critter under magnification for specific identifying features rather than at a photo, I wasn’t sure if it was BMSB. BMSB can be distinguished from other stink bugs by its speckled appearance, white stripe on the antennae and the black and white banding on its abdomen.

According to Rutgers University, the BMSB is a significant nuisance for homeowners and can be devastating for farmers. This invasive species was accidentally introduced to the U.S. from Asia in 1996 and found in Nevada in 2016. They have a "shield" shaped body that is characteristic of all stink bugs. The adults are approximately 5/8-inch-long with a mottled brownish grey color.

The next to last antennal segment has a white band and several of the abdominal segments protrude from beneath the wings and are alternatively banded with black and white. The underside is white, sometimes with gray or black markings, and the legs are brown with faint white banding.

Stink bugs emerge in the spring and early summer to feed on a number of fruits, vegetables and other plants. They can be found on house siding or inside a home. They do not sting or bite, but defend themselves with their characteristic “stink.”

The smell is not always evident. They usually only release the odor when they feel threatened and people's sensitivity to the smell varies. Adult BMSB tend to live between six to eight months.

Presently, there are no viable strategies for control of the BMSB. Insecticides are short-lived and the bugs rapidly develop resistance to the chemicals. Even where insecticide is effective, repopulation occurs through migration from non-treated areas.

Prevent them from entering your home as much as possible. Placement of screens over windows, doors and vents, removal of window air conditioners and caulking cracks in windows and doorframes will deter the adults from entering.

Removal of window air conditioners is important, as numerous BMSB will enter this way. If small numbers occur indoors, they can be removed either by hand or by using a shop-vacuum.

For information, go to: https://njaes.rutgers.edu/stink-bug/identify.php.

JoAnne Skelly is Associate Professor & Extension Educator Emerita, University of Nevada Cooperative Extension. skellyj@unce.unr.edu