PENNSYLVANIA (WHTM) — As temperatures start to drop and the weather becomes chillier, you may start to see more small insects trying to call your home their own.

One of these bugs is one of the smelliest: The dreaded stink bug. But are these pests invasive to the state of Pennsylvania?

Penn State said that they are absolutely invasive! They can even be a serious threat to fruit vegetables and other crops. The brown marmorated stink bug, commonly found in the Keystone State was accidentally introduced from East Asia into eastern parts of Pennsylvania. The bug was first collected in 1998 near Allentown and was probably introduced several years earlier.

Since 1998, Penn State said that the bug has spread through most of North America, with the bug predicted to be found continent-wide within a few years.

Erlich said that we see these pests mostly during the fall months since they are seeking shelter to survive the winter and that they are also trying to seek out a potential mate. A stink bug is also sometimes called a shield bug and is usually brown and grey in color.

The reason these bugs are called ‘stink bugs’ is due to their defense mechanism. When they are threatened or when they are squashed, they emit a very harsh odor. Usually, this is enough to deter predators, but it makes getting rid of stink bugs a headache, as you try to get them out without killing them. You could end up with a home that smells foul from trying to remove and kill them.

Erlich says that during the fall months, swarms of these bugs will appear in trees and the warm side of your home or apartment, and they will crawl into every crack they can to keep warm. the main thing to do is make sure your home is sealed and that screen doors and windows are repaired and holes are covered.