Plant Health Initiative

Brown Marmorated Stink Bug (Halyomorpha halys) - a new invasive pest

From Brown Marmorated Stink Bug Found in Iowa and Illinois, by LeAnn Strother, Soybean Review, April 2011

The Brown Marmorated Stink bug is similar in shape and size to several native insects such as the brown stink bug, assassin bug, and squash bug. Click on image to view the Illinois Extension pest ID poster (pdf)

In February, Iowa State University Extension and state agricultural officials confirmed that a single dead specimen of the brown marmorated stink bug (BMSB) had been collected in the state. It was the first confirmation of this pest in Iowa. Because the BMSB travels readily in shipping containers and with people, it was not known whether the find indicated an established population or an isolated individual.

Originally from Asia, the BMSB was first found in Pennsylvania in 1998. Since then, it has been making its way across the United States. In Illinois, the presence of the brown marmorated stink bug has been confirmed in two counties.

Impact

There is concern that established populations of BMSB could become pests in crops, gardens, and landscapes in the midwest, as they have in eastern states. BMSB feeds on sap of host plants including field crops (particularly legumes, including soybeans), as well as many fruits, vegetables, shade trees and other woody ornamentals. The bug feeds by puncturing plant tissues, especially fruits and seed pods, and sucking out the plant juices with its mouthpart, similar to aphids or leafhoppers.

The brown marmorated stink bug, like all stink bugs, tend to aggregate at food sites. Click on image to view a larger version. Photo credit: G. Hamilton, Rutgers University

In addition to the damage they do to crops, BSMB adults annoyingly migrate into houses and other buildings in the fall to overwinter. In fact, homeowners are generally the first to notice the BSMB’s presence as it invades their homes. Homeowners on the East Coast describe the stink bugs as worse than box elder bugs and lady beetles combined. Fortunately, the stink bug will not reproduce inside structures or cause damages.

 

Identification
“Marmorated” describes the BMSB’s marble-like coloration on the body. Adults are approximately one-inch long, with the typical shield shape of a stink bug. The characteristics that set it apart from other stink bugs are the white banding on the antennae, the distinctive pattern on the edge of its wings, and its red eyes. BMSB have small, round, copper-colored or metallic blue depressions on the head.

Nymphs have a yellowish to off-white abdomen, and just before adulthood, their abdomens have reddish spots.

 

Brown marmorated stink bug - older nymph. Photo credit: Gary Bernon, USDA APHIS

Green and brown stink bugs
In spite of recent attention to the BSMB, farmers should also be aware of several other stink bugs that can be found in north central soybeans. Many producers are familiar with green stink bugs (Acrosternum hilare) and brown stink bugs (Euschistus servus) in fields. These bugs are attracted to soybean plants in the bloom to early pod-fill stages when they begin feeding on developing seed. Direct feeding can lead to reduced seed quality and secondary seed rot.

Beneficial stink bugs
Not all stink bugs found in soybean fields are pests. Some are beneficial. The spined soldier bug is a common stink bug species that preys on pest insects, especially larval forms of pest caterpillars and beetles. The spined soldier bug is found in soybeans after blooming and can be identified by very sharp pointed “shoulders” and dark wing tips.

The Brown marmorated stink bug (above) is not the same as the native brown stink bug (below), although they look very similar. Photo credit: D. Lance USDA APHIS .

Brown stink bug. Photo credit: Russ Ottens, University of Georgia.

Monitoring efforts

Though stink bugs are considered a major pest of soybeans in the southern parts of the country, they have not yet become a significant cause for concern among Midwestern farmers. However, David Wright, director of contract research at Iowa Soybean Association and NCSRP, warns, “As we experience climate changes, particularly due to milder winters, we can expect new challenges posed not just by stink bugs, but by other pests, as well.”

Because stink bugs are on the move, Illinois Extension entomologist Mike Gray says a survey will be conducted in Illinois this summer to research the presence of all the aforementioned species, as well as the red-banded and red-shouldered stink bugs, which have been observed in several southeastern states and cause significant management challenges.

Farmers and homeowners who observe insects similar to the BMSB are encouraged to submit a sample or send a digital photo to their state university diagnostic clinic or their state agricultural pest survey office.

 

Links

Brown Marmorated Stink Bug: Know This Invasive! University of Illinois, Extension

Stink Bugs and Similar-Appearing Insects in Iowa Iowa State University Plant and Insect Diagnostic Clinic

Stink Bugs on the Move Integrated Crop Management News, Iowa State University

Brown Marmorated Stink Bug: Ohio State University Extension Fact Sheet FS-3824-08 (printable pdf)