With a return to warm weather this week, stink bugs made their presence known around homes and offices as they accumulated on windowsills, walls, and doors and busily buzzed about indoor lights at night. Why all the activity at this time of year? The answer lies in the age-old pattern of life crafted by the stink bug to survive the ravages of winter and emerge just in time to take advantage of bountiful leaves and fruit found on plants each spring. Millions of folks in the middle-Atlantic region were treated to invasions of stink bugs last autumn as the horde sought refuge in homes, schools, and office buildings. Many people mistakenly believe that stink bugs enter buildings in winter to “get warm’ but this is not the case.
Why are they found in homes
In the natural realm where stink bugs evolved over millions of years, stink bugs sought winter refuge in sheltered spots like rocky crags, fallen trees, or tangles of brush in the forest. Here, protected from the onslaught of winter, stink bugs chilled out and entered a season of inactivity akin to hibernation awaiting the return of favorable temperatures and springtime food. Lengthening days of spring warmed the cliffs and forests and signaled the return of leaves, flowers, and fruit. With the return of food sources, stink bugs answered Mother Nature’s wake up call and moved from their refuges to the greening landscape. During March, consistently warm temperatures and the vernal explosion of flowers, fruit, and leaves are still several weeks away. But inside attics or beneath the siding on a home, an unusually warm day in late March convinces stink bugs that spring has arrived and that it is time to return to the wild to seek food and pursue the biological imperative of finding mates and laying eggs. As our average daily temperatures rise and chilly days that are the norm are punctuated by summerlike days here and there, stink bugs will be on the move in homes and buildings. For some this winter, there was no respite from stink bugs. They were active all winter long.
Laying eggs in homes
A colleague who lives in a rural Maryland home has collected more than 15,000 stink bugs since January 1, 2011. Yikes! For most of us, the tide of stink bugs that rolled in this autumn is about to roll out over the next two months. Here are some things to consider. Recently, as I spoke with folks, one question that often came up was “do stink bugs breed in my home?” The answer to this question to the best of our knowledge is no. In the normal course of events, stink bugs move from winter refuges to plants outdoors where they feed for several weeks before they become competent to lay eggs. In your attic or an unused bedroom there is simply no food to provide the sustenance needed by stink bugs to produce eggs. Even if a stink bug laid eggs indoors on a windowsill or wall, there would be nothing to sustain the young bugs which require plant food for growth and development.
Having made this claim, I might back-peddle just a little, as we are receiving reports of stink bugs feeding on house plants such as orchids and potted ponytail palms. Will they lay eggs on houseplants indoors? In theory they might, if they feed for prolonged periods of time and if the plant is suitable for reproduction, but only time will answer this question. Another question that always comes up is “what should I do about stink bugs that appear in my home this spring?” Sweeping, vacuuming, or simply picking them up and disposing them is still our recommendation for control indoors. Because they will be active for a relatively long period of time and to reduce exposure of homeowners and their children and pets, we are not recommending the application of insecticides indoors to control stink bugs as they appear. Will stink bugs be as problematic this year as last? The answer is likely yes. As stink bugs spread and our region continues to become infested, more people will witness stink bugs on their vegetables, and fruit trees, and landscape plants outdoors to be followed by domestic invasions of stink bugs in autumn. But the news on stink bugs is not all bad. In some areas that have been infested for several years such as my landscape in central Maryland, 2010 really was no different than 2009 with respect to the stinkers and I anticipate little if any increase in numbers in 2011. What can be done about stink bugs in the long term? More than 50 scientists throughout the region and across the nation have banded together in a major research effort to thwart the continued depredations of this nefarious bug. We will explore all possible methods of controlling stink bugs including the use of traps and trap crops, release of natural enemies, development of natural, synthetic, and microbial insecticides, genetic manipulation to kill the bug, modification the bug’s habitat, methods to exclude and remove pests from homes, and the use of stink bug resistant plant materials. Stay tuned.
References:
To learn more about the brown marmorated stink bug, please visit the following web sites.
http://pestthreats.umd.edu/content/documents/BMSBBulletin1_10-2010_000.pdf
http://www.hgic.umd.edu/content/brownstinkbug.cfm
http://ento.psu.edu/extension/factsheets/brown-marmorated-stink-bug