By now, you’ve probably become familiar with that strange smell – a little like coriander, a little like burnt rubber, and just overall pungent and off-putting. As soon as that smell wafts under your nose, you know what to look for: little shield-shaped, grayish brown insects with stripey antennae. Yes, it’s everyone’s favorite friend in the fall, the brown marmorated stink bug (BMSB).
BMSB is an invasive species introduced from east Asia, where it is an agricultural pest. Unsurprisingly, the bug has become an agricultural pest here in the Midwest as well. First seen in Pennsylvania around 1998, BMSB has spread throughout the US and Canada. It’s not to be confused with our native stink bug, but it seems like they’re not as commonly seen these days as the non-native one.
Stink bugs typically become active in late spring to mate and lay eggs. The nymphs that hatch from these eggs will cause agricultural damage as they feed (they will eat anything from tomatoes to soybeans). By the time fall rolls around, these nymphs will have reached adult stage and will start looking for a place to spend the winter.
BMSB seeks entry into structures and homes beginning in late September and early October. They might hitchhike on your shoulder or shirtsleeve before flying to a wall or resting on the carpet. They may also crawl in through window seals and doorframes, particularly if they aren’t well-sealed. Similar to the Asian lady beetle, these insects will congregate on hot surfaces (like brick on the south side of a home), sometimes making it difficult to enter the home without a swarm of bugs following you inside.
When disturbed, stink bugs will release that funky odor. It’s not the most offensive odor in the world, but it is certainly pungent and noticeable, especially indoors. That’s the bad news – they smell strange. The good news is that they will not cause structural damage and they will not bite. Stink bugs have special straw-like mouth parts used to puncture plant tissue and siphon liquid out, so they are not physically equipped to deliver a painful bite to other organisms.
So what can you do to minimize their malodorous impact on your home? The best defense against stink bugs is a well-defended perimeter. Before they get inside, you can take care to make sure window frames, door frames, soffits, utility exit points, and siding are in good condition and sealed properly. Window screens should also fit well and be free of holes and other damage. You may also choose to apply an insecticide around the perimeter of your home. Insecticides used to control stink bugs often contain neonicotinoids, so these may not be the best choice if you are concerned about honeybee populations in your area. Insecticides are best applied before the first major flights of stink bugs begin. At this stage in 2018, it is too late to apply insecticides that will have a noticeable impact on populations.
Once the bugs are inside, a soapy bucket of water might be your best treatment option. Simply manually removing the bugs from where they rest and dropping them in soapy water will kill them and subdue their odor. You may also use a vacuum cleaner to dispose of them. As you might imagine, a vacuum cleaner is quite the “disturbance,” so the bugs will likely emit their odor on the way into the machine. Best of luck on your stink bug crusade – they will likely be constant companions in the fall for years to come.