Brown Marmorated Stink Bugs
By: Jess King, Entomologist
The last few days of September there were signs of adult brown marmorated stink bugs in parts of Northern Delaware. October 1st the brown marmorated stink bugs began their assault on homes. It's October 4th today and it seems like there is heavy activity around all structures in N. Delaware. The activity may seem like an "assault" on a home but these insects do not bite other animals and do not destroy homes. They may damage tomato plants or other garden favorites. It's encouraged to pick your tomatoes towards the beginning of September to avoid this fruit damage caused by the brown marmorated stink bugs.
The brown marmorated stink bugs are attempting to survive the upcoming winter by finding suitable locations to prepare for the freezing temperatures. Man made structures are ideal for their overwintering behavior. brown marmorated stink bugs are able to enter structures through small cracks and crevices around homes. The soffet of roofs, unscreened attic vents, chimneys, damaged facias, under siding, around unsealed exterior window frames, loose fitting window screens, under doors in need if a door sweep, open windows and doors without screens, basement/crawlspace windows and vents on plants or materials brought indoors for the winter are some ways these insects get into the structure.
Insects respond to clues including increases and decreases in day length (longer in the summer and shorter in winter) and temperature to successfully overwinter. The insects find a suitable location inside the structure, pump an insects version of anti-freeze through their bodies and shut down for the winter. This doesn't always happen perfectly for insects. When the brown marmorated stink bugs enter the living space of the home they find it warm and light inside and continue with their activity. Some will overwinter for a while in a secluded wall void or other place and get attracted to light or warm temperatures when the heater comes on in the winter and come out in the middle of winter. Because of the continued activity throughout the winter, inside a home, the misconception can be that the brown marmorated stink bugs are reproducing in a home, but they are not. The insect reproduces in the summer, outside, laying eggs under leaves. The brown marmorated stink bugs just don't know the difference between inside a home and outside a home and just come out if an overwintering spot when the cues present themselves.
The insect doesn't last long in the home, without the ability to locate food or water inside a home the insect usually desiccates and expires in the home. It's important to clean up the carcasses as they will quickly become food for the scavenging carpet beetles. When the carpet beetles find the brown marmorated stink bugs you will find them hollow with little holes where the beetle larvae got inside to eat. This is also why it's critical to not use pesticides inside a home to kill the brown marmorated stink bugs in wall voids or other inaccessible areas. This can lead to a severe carpet beetle infestation.
So here is the plan to reduce the amount of brown marmorated stink bugs that enter your home. Do it now! If you wait 2 more weeks it may be too late depending on the level of activity in your geographical area. Caulk up cracks and crevices around the outside of the home and exclude them mechanically from their known entry points if at all possible. Make sure you have tight fitting screens in the windows. It may be helpful to have small fires in the fireplace to drive them out of a chimney and be sure to keep the flue shut when the fireplace is not in use.
Get exterior preventative insecticide treatments now to reduce the amount that successfully make it inside a home. Brown marmorated stink bugs are attracted to light. Install a commercial insect light trap in the attic or rooms where the most activity occurs, if no attics spaces are in the home. The insect light trap will need to be serviced frequently as they will quickly fill up with brown marmorated stink bugs and other overwintering insects. This harvests the insects that made it through the exterior applications to the home.
The brown marmorated stink bugs activity mayincrease inside a home in the spring. The insect is attempting to leave its overwintering site. Again, this insect does not know the difference between the inside and outside of a home, it's just emerging from its overwintering location. It's intention is not to be in your home but to be outside feeding and reproducing. It can be helpful to caulk any interior cracks and crevices and mechanically exclude the bmsb's from the living space of a home if they are known to emerge from the inaccessible areas into the living space. The best thing to do in the spring is let them leave and get prepared for next fall when they are likely to come back.
Be proactive and provide mechanical exclusion along with exterior preventative treatments before you see the adult activity next year. The ideal time for this work is around the beginning to middle of September as the temperatures begin to noticeably decrease along with the decreasing day length. If you really pay attention you can identify the younger stages of the bmsb's around August to determine if you will have adult activity coming.
Call Royal Pest at 800-ROYAL-PEST (800-769-2573) or visit http://www.royalpest.com/index.php/active-pests/stink-bugs