– Christine Gelley, OSU Extension Agriculture and Natural Resources Educator, Noble County, Ohio
Like many other creatures, ladybugs and this brown marmorated stink bug are responding to cooling temperatures, fewer hours of sunlight, and diminishing sources of food, and moving in doors.
The theme of the past week on my radar has been all about bugs. From programs about scouting for spotted lanternfly to the annoyance of multicolored Asian lady beetles (MALB) and brown marmorated stink bugs (BMSB) crawling and flying around my house, bugs have been on my mind. I bet they’ve been on yours too.
Every year in the fall there are complaints about uninvited six-legged home invaders trying to shack up with us for the winter. From ladybugs (which are most likely multicolored lady Asian beetles, not true ladybugs), to pine seed beetles (often called stink bugs), to brown marmorated stink bugs (stocky brown stink bugs with a shield shaped back), to various other pests, homeowners are often overwhelmed by the number of invaders. They commonly reach out wanting to know where they came from and how to get rid of them.
Let’s address the answers to those two questions for both MALB and BMSB.
Where did they come from?
The multicolored Asian lady beetle is part of the group of lady beetles that are considered beneficial predators in agricultural settings. The ladybug is the state insect of Ohio. The MALB is a lady beetle that is native to Asia and was likely accidently imported to North America through shipping ports and intentionally introduced in multiple states in the USA and Canada to help manage insect pests of trees. But in the early 1990s, MALB became recognized as a problem insect in North America and across the globe. The reason they become a problem to us is their winter preparation behavior. They seek out hibernation sites in clusters.
The brown marmorated stink bug a pest of a wide range of plants from which it feeds on plant sap. Its original native range is Japan, Korea, and China. It is believed to have been accidently imported into the USA and was first identified in 2001 in Pennsylvania. As of 2020, BMSB has spread to 46 states. It is an avid hitchhiker and can easily be transported through human travel and begin new reproductive populations. The bugs feed on over 175 different kinds of plants and are severe pests of fruits, vegetables, field crops, and even ornamental plants.
Like many other creatures, ladybugs and stink bugs are responding to cooling temperatures, fewer hours of sunlight each day, and diminishing sources of food. The best way to conserve their bodies’ energy until spring is to find a warm place to rest through the winter. As plants dry out, ladybugs and stink bugs tend to congregate in the afternoon sun on south facing surfaces (like your house). They seek shelter in cracks and crevices together, which can lead to many bugs sneaking in through windows, doors, soffits, essentially crack larger than an eighth of an inch. Neither ladybugs or stink bugs reproduce inside. They do not cause structural damage to homes, and they do not carry disease. They are annoying, smelly, and can leave discoloration on walls when disturbed.
How do I get rid of them?
Sealing cracks and crevices is the single best way to keep these bugs from entering your home in the fall. Scout your home for potential entry points in the spring and seal them before fall comes. Once in your home, ladybugs and stink bugs are primarily a nuisance. They do excrete a stinky smell and can stain surfaces, due to the secretion they exude when startled. Pets will often chase and startle the bugs leading to stains on walls, windows, and floors. People should avoid touching their eyes and nose after handling the bugs and their secretions due to the acidic nature of the liquid, which can irritate the nasal cavities.
Pesticides are generally ineffective once the insects are inside. There are treatments that you can apply safely to the exterior of the home, but they will not give you complete control. The safest, quickest, and most sanitary method for controlling ladybugs and stink bugs inside is to suck them up with a vacuum cleaner. This method of removal results in minimal surface staining. An easy way to collect them without them winding up in your vacuum cleaner bag is to attach pantyhose to your vacuum nozzle to create a filter inside the nozzle. Then you can bundle the bugs up in the panty hose, secure with a tie or rubber band, and dispose of them in the trash.
To continue learning about ladybugs consult the OSU fact sheet “Multicolored Asian Lady Beetle” by Joe Boggs and Susan Jones on Ohioline at https://ohioline.osu.edu/factsheet/ENT-44.
To continue learning about stink bugs consult the OSU fact sheet “Brown Marmorated Stink Bug” by Celeste Welty, Jim Jasinski, and Kelley Tilmon on Ohioline at https://ohioline.osu.edu/factsheet/ent-90.