Have you recently noticed an increase in the number of ladybugs in your home? You are not alone.
These probably aren’t actually the ladybugs you’re thinking of. There’s a good chance you’ll see an increase in what’s called the Asian ladybug.
Even though they can be a nuisance, how worried should you be?
Here’s an overview of what you need to know:
What are Asian ladybugs?
According to the University of Minnesota, multi-colored beetles look similar to other ladybugs, but are usually slightly larger. They are often seen in colors like orange or yellow, but can be seen in red or black, although the latter is rare.
The beetles typically have 19 black dots, although some may have fewer or none at all, and they have a “clear black ‘M’-shaped mark behind the head, the university notes.
Other names for the beetle include the Halloween ladybug and the Japanese ladybug.
Why are there so many at the moment?
People most often notice insects in their homes in the fall, according to Peggy Anesi, a natural resources, environment and energy educator at the University of Illinois who specializes in wildlife management.
“Like many insects, the ladybug begins to seek out small crevices to gather in large numbers and begin diapause, the name for insect hibernation,” she wrote in a blog post for the university. “They often inadvertently crawl into basements through cracks in the foundation.”
She noted that the large numbers of these beetles can be alarming to some.
“The Asian ladybug’s self-invitation has my phone ringing as early as Halloween. Most people, not exactly naturalists, won’t tolerate even a single insect in the house, so imagine the call when someone locates an entire yard full of ladybugs in the corner of their basement,” Anesi said.
Similarly, the University of Minnesota stated that “once ladybugs move into wall voids in the fall, there is no way to prevent them from emerging later in winter or spring.” .
Are they harmful?
The University of Minnesota notes that beetles “can be a nuisance when they occur in large numbers inside homes,” but overall they are not harmful to humans or pets.
They do not damage property and cannot sting, but they can bite if seeking moisture or food and can secrete a “strong-smelling yellowish liquid” that can stain some light-colored surfaces.
“If you disturb a ladybug, you will be amazed at how much foul odor from yellow discharge it can admit through the joints of its legs,” Anesi said. “It’s their defense mechanism that stops other animals from trying to catch them.”
Although beetles are common in woodland areas and gardens, they can be beneficial because they feed on garden pests such as aphids. But if they run out of aphids to eat, they may start looking for other food sources and land on fall fruits like grapes or apples, infesting those with wounds or holes.
Can you prevent these beetles from infesting your home in the fall?
Experts recommend eliminating spaces where these beetles can enter your home, although this can be difficult because these insects can fit through openings as small as 1/8 inch.
The timeline for plugging the openings would be before the end of September, according to the University of Minnesota.
Here are some of their recommendations:
- Check the exterior of your home for gaps and cracks that could allow insects to easily enter.
- Ladybugs can fit through openings as small as 1/8 inch.
- Make necessary repairs before the end of September.
- Seal cracks and gaps around doors, windows and fascia boards. Check for gaps and cracks where different materials meet, such as brick and wood siding. Seal cracks with caulk, such as silicone, elastomeric latex, or silicone/acrylic.
- Seal areas where cable television wires, telephone lines and other utility wires and pipes, exterior veneers, dryer vents and similar objects enter buildings.
- Seal with caulk or, for larger gaps, use polyurethane expanding spray foam, steel wool, copper mesh or other suitable sealant.
- Repair or replace damaged window and door screens.
- Repair or replace damaged screens in roof and soffit vents, as well as bathroom and kitchen fans.
- Install door sweeps or thresholds on all exterior entry doors. Install a rubber seal at the bottom of garage doors.
You can also use a pesticide outside to prevent entry into your home, some experts say. Others say pesticide spraying is “unnecessary.”
What can you do if they are already at your house?
Once inside your home, spraying pesticides against these beetles is largely ineffective.
However, experts are divided as to the preferred method for eliminating Asian ladybugs.
Anesia suggests sweeping the beetles out of your house “because if you vacuum up a bunch of them in the winter, the smell will make you change the vacuum cleaner bag before it’s full.”
The University of Minnesota, however, said vacuuming is a viable option, but it also notes that “ladybugs are not automatically killed when vacuumed up,” so changing the bag frequently is recommended to minimize odors.
“You can use a knee-length nylon stocking that has been inserted into the extension hose and secured with an elastic band. When vacuuming, ladybugs are captured in the stocking,” the university suggests. “Remove the stocking after vacuuming so any captured beetles don’t escape.”
