The brown marmorated stink bug (BMSB), Halyomorpha halys is becoming more well-known as it appears in more and more counties around the state and in more and more homes in the counties where it was previously reported.
BMSB was first reported in Iowa in 2011 and since has been reported in 23 counties. We continue to document reports of BMSB in counties where it has not been previously reported. See the map below and please let us know if you find BMSB in an unmarked county.
BMSB is a sap feeding insect that feeds on sap from green, growing plants during the summer and then wanders indoors by accident in the fall. It is an accidental invader similar to the boxelder bugs and the multicolored Asian lady beetles.
Recently, The New Yorker magazine had an article that documented the misery when this dime-sized insect wanders indoors in the fall of the year. ("When Twenty-Six Thousand Stinkbugs Invade Your Home" in the March 12, 2018 issue of The New Yorker)
The article mentions thousands or tens-of-thousands of BMSB found indoors in eastern states. Fortunately, the experience in Iowa has been many, many fewer. Iowans we have talked to report "one," "a few," or "several" stink bugs in their homes. We have had reports of "dozens" on the south side of the house in October, but, so far, no one in Iowa has mentioned hundreds, let alone thousands or tens-of-thousands. Whew.
Late Winter Appearance
Every stink bug, boxelder bug, or lady beetle you find indoors in winter, regardless of when, crawled indoors through a crack or gap in October. It is typical for individual stink bugs to stagger into view at various intervals. Though they have been in the house for approximately 5 months some manage to stay hidden inside the walls or attic voids for varying amounts of time. Ones that remained hidden earlier may come out and crawl into view at any time. They are not “new” insects; they are "old" insects that remained out of sight longer than some others. The random appearance may continue most of the winter. Accidental invaders cannot reproduce indoors; they cannot lay eggs in the walls or attic voids.
The suggested control for stink bugs inside the house is to sweep or vacuum up and discard. Sprays are of little to no benefit.
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