Brown marmorated stink bug spring update 2014

Sightings in Michigan homes on the rise.

Brown Marmorated Stink Bug sightings.
Brown Marmorated Stink Bug sightings.

Spring has arrived and we’re measuring the effects of the hard winter a little at a time. The pavement and grass has reappeared from underneath the snow and ice. One insect in particular seems to be on people’s minds – the brown marmorated stink bug (BMSB). Beginning about three weeks ago, there was a dramatic increase in sightings of this pest inside Michigan homes. The longer days and periodic warmer temperatures are causing BMSB adults to become active in their overwintering locations, moving about in the warmth of homes, always ready to find their way outdoors when temperatures become warmer.

USDA researchers have discovered that dead, standing trees in woodlots are another favorite overwintering location for this insect. A recent study by Virginia Tech researchers, led by entomologist Thomas Kuhar, suggests that the long extreme cold periods this winter may have severely impacted BMSB overwintering outdoors. A 95 percent kill rate was recorded for adult bugs held in insulated buckets and placed outdoors during the January polar vortex. Kuhar admits that his intention was to point out the unusually high death rate in his buckets, rather than infer that stinkbugs in their natural overwintering sites suffered the same fate. Indeed, other experts expect to find no more than 50 percent mortality for stinkbugs overwintering under bark and in homes. Still, winter mortality is expected to be above the typical level of 25 percent. We anticipate that the severe cold had an impact on BMSB overwintering outdoors in Michigan, but in the warmth of your attic or under siding, not so much. The bottom line is that whether or not the cold winter has proved beneficial with respect to BMSB activity this summer is unknown.

IPM Diagnostic Services at Michigan State University reports that BMSB has now been collected in 18 Michigan counties (see map), the last several specimens collected during the winter from homes. Homeowner complaints were the highest they’ve been for this insect last year. If the scenario plays out here as it has in other states, reports from homeowners of BMSB being a nuisance as it finds places to overwinter, will rise sharply before it becomes an agriculturally important pest.

At the end of last summer, when soybeans were still green and apples were ripening, a localized infestation occurred in soybeans bordering apple orchards in the Stevensville, Mich. area. In this instance, they never moved into the orchards and damaged the apples. Our trapping network, begun in 2011, the year after the first BMSB was found in the state, captured a large number last year in both the Stevensville and Lansing areas.

You can find up-to-date information on BMSB through the Michigan State University Extension fruit and nut topic page throughout the season, including new sightings and current knowledge from research conducted throughout North America. Information on managing this pest can be found in the recent edition of the Michigan Fruit Management Guide (E154). Meanwhile, if you are looking for a good place to go for information about this invasive pest you can find it at, a website maintained by the Northeastern IPM Center.

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