As the growing season winds down insects, arachnids, and other arthropods have usually reached the height of their populations but are also starting to run out of time. With food on the decline and temperatures dropping, these animals will start to look for somewhere to hide and one of their top choices will be inside of your home, garage, or shed. There are lots of different creatures you may encounter but some are more frequent visitors than others and it is helpful to be able to recognize these.
Boxelder bugs - Adult boxelder bugs are black with orange/red marks and are about 1/2 in. long. Their wings lay in such a way that they form a red “X” on the back and they also have 3 red stripes behind their head. When smaller they are all red with a yellow dot on their back. Boxelder bugs live in boxelder/maple trees in the summer but in autumn they move out of trees to find winter hiding spots. They often end up on/in homes with large western and southern facing exposures. They are inactive in the winter, save for warm days where they may start crawling around.
Millipedes - Small, tube-shaped arthropods with many legs. They range from black to a grey-brown color and range from .5 an inch to 1 inch long. We often find them in basements, garages, or by washing machines as they tend to like humid/wet areas. They feed on decomposing material like dead leaves or fungi. Millipedes normally perish soon after coming inside due to the dryness of indoor air.
Wolf spiders - There are many types of spiders you may find indoors but wolf spiders are probably the most common in the fall. Including their legs, wolf spiders can be between an inch wide up to 3 inches in width. They are usually dark brown with strips of yellow-brown down their back. Wolf spiders usually live in lawns and landscapes but will follow their prey and seek warmth inside as autumn arrives. They pose no medical hazard to people and don’t survive long inside.
Multicolored Asian Ladybeetle - An invasive insect from Asia that becomes an indoor pest in the fall as it tries to overwinter in your home or underneath your siding. They can be light or dark orange, and can have many spots or none at all. Positively identify them by looking for the solid or broken “M” on thorax. Multicolored Asian ladybeetles can bite when handled and create a musty odor when disturbed.
Managing fall invaders
Fall invaders are mostly an annoyance posing little threat to our health or structures. However, you can take proactive steps to ensure you deal with as few as possible in your home. Physical exclusion from the home is the most surefire way to not deal with fall invaders. Check and seal up holes in caulking around the house, ensure all screens are in place, and ensure doors seal properly. One organic control option is using traps, such as glue boards, to snare invaders. These traps should be placed near doors or windows to maximize effectiveness. Finally, you can use perimeter sprays of products like bifenthrin around the exterior of your home. Most of these would be applied in a three foot band around the home.