Knock on wood, but I have never seen a slug here in Colorado. Although I am sure there must be someplace here that is moist enough to allow them to survive.

Also, due to low humidity, our insect population in general is smaller. Little bugs have little protection from drying out and dying. Too low of humidity for dust mites to do well even.

But that doesn't necessarily mean that plants don't get infestations. If a plant comes into the seller infested, likely from out of state sources, then you can get bugs. In my 16 years living here, I have had only one house plant that had bugs, spider mites. A gardenia. My dedication to the plant was low so after trying Safers a couple of times, I decided to get rid of the plant rather than risk spreading to the rest in the house. I only had a couple of phals during this time.