Centipedes, pillbugs, millipedes, stink bugs, and a handful of other pests show up in Arizona homes throughout the year without necessarily fitting a category of their own. None of them are usually a major infestation risk on their own, but they’re common enough that most East Valley homeowners run into at least one of them eventually. The good news is they’re all handled the same way, through a perimeter that keeps pests out generally rather than needing a different plan for each one.

What are occasional invaders?

Occasional invaders is a general term for pests that wander into a home from outside without actually wanting to live there. They’re usually looking for moisture, shelter, or just passing through, and once inside a house they tend to dry out or run out of food fairly quickly rather than establishing an ongoing population. That’s different from a pest like German roaches or bed bugs, which specifically want to live and breed indoors.

Centipedes are fast moving, many legged, and usually a yellowish brown color in this region. They’re drawn to damp, dark areas like bathrooms, garages, and basements, and while a bite is possible if one is handled directly, it’s uncommon and typically no worse than a bee sting.

Pillbugs, sometimes called roly polies, are small, gray, and roll into a ball when disturbed. They’re harmless and feed on decaying plant matter, usually found under pots, mulch, or landscaping rocks rather than actually inside a home.

Millipedes are similar in appearance to centipedes but move slower and have two pairs of legs per body segment instead of one. They’re also drawn to moisture and decaying organic matter and, like pillbugs, are more of an outdoor nuisance that occasionally wanders inside.

Stink bugs are shield shaped and, true to the name, release an odor when disturbed or crushed. They’re mostly a seasonal issue, showing up in larger numbers as the weather cools and they look for a warm place to spend the winter.

Signs you have occasional invaders

• Finding one or two unfamiliar bugs inside, especially near doors, windows, or damp areas like bathrooms and garages
• Increased sightings after rain or as the seasons change, since moisture and temperature shifts are what drive most of these pests to move
• Pillbugs or millipedes clustered under pots, mulch, or landscaping rocks when they’re moved
• A sudden smell if a stink bug is disturbed or crushed indoors

A single occasional invader inside the house usually isn’t something to worry about. Regular sightings, especially in the same spot, point to an entry point nearby that’s worth sealing up.

Are occasional invaders dangerous?

No, not in any meaningful way. None of these pests are aggressive, none carry disease, and none pose a real risk to people or pets. Centipede bites are the closest thing to a concern here, and even those are uncommon and mild for most people. These are nuisance pests, not health or safety issues.

Why do these pests keep showing up?

Nearly all of them are chasing the same thing, moisture, and Arizona’s dry climate makes any consistently damp spot around a home unusually attractive to them. Over watered landscaping, mulch beds, irrigation leaks, and gaps around doors and windows are the most common paths in. Seasonal shifts play a role too, since cooling temperatures in fall push a lot of these pests to look for a warmer, more sheltered spot, which is often the outside wall of a house before it’s the inside.

How Trellis handles occasional invaders

This is where a real perimeter barrier does its job. Rather than treating for each individual pest on this page separately, our Triple Lock Protection System addresses the yard, fenceline, and perimeter of the home as a whole, which reduces entry points and general pest pressure for all of these pests at once, not just the ones on a checklist. It’s a broader approach because these are broader pests, there’s no single treatment aimed at just centipedes or just stink bugs, the goal is a home that’s harder for all of them to get into in the first place.

Occasional invader coverage is included in every general pest membership at no extra charge, and it’s covered under your regular bi-monthly service.

How much does this cost?

Coverage for occasional invaders is included in our general pest service, no separate specialty charge. Pricing is based on home size, the same as the rest of general pest coverage, and it’s handled during the same bi-monthly visits as everything else.

Can I handle these myself?

Reducing moisture around the home, fixing irrigation leaks, thinning out heavy mulch, and sealing obvious gaps around doors and windows all help reduce how many occasional invaders make it inside. It won’t stop every single one, since some level of activity is normal in this climate, but it does cut down on how often they show up.