At a glance
- The Arizona bark scorpion is the species most often found inside Phoenix-area homes, and its sting is the only scorpion sting in the United States considered medically significant.
- Bark scorpions can go weeks or months without eating and spend the day in block walls, landscape rock and wall voids, which makes them harder to reach than most household pests.
- Scorpion activity in the Phoenix area rises as spring nights warm up, stays high through summer and monsoon season, and drops off in late fall.
- Platinum Pest Management pairs regular exterior treatment with sealing gaps, because sprays alone rarely keep scorpions out of Arizona homes.
- Bark scorpions glow blue-green under ultraviolet light, so a blacklight check after dark shows where they are active around a house.
On this page
Where new scorpions come from after a treatment
A first treatment kills many of the scorpions living around a house, but new ones keep arriving from washes and neighboring yards. That steady supply is why scorpion control in Arizona works best as regular maintenance. Homes that back onto preserve land or open desert see the most new arrivals, including many streets in Ahwatukee, Apache Junction and northeast Mesa.
How Arizona bark scorpions live around homes
The Arizona bark scorpion is the species behind most indoor scorpion calls in the Valley. Adults are light tan and about 2 to 3 inches long, with slender pincers and a thin tail. Its sting is the only scorpion sting in the United States considered medically significant. In healthy adults it usually causes intense pain and tingling, while symptoms tend to be more serious in young children and older adults.
Bark scorpions are nocturnal and spend the day wedged into tight spaces. Around a typical East Valley house, that means block wall gaps, the space behind the weep screed, landscape rock, woodpiles and dead palm fronds. They climb stucco and tree trunks easily, which is how they reach roofs and attics and why they turn up on ceilings indoors. A scorpion can also flatten its body enough to slip under a door with a worn sweep.
In the cooler months, bark scorpions often shelter in groups, so one sighting can mean others are close by. A female carries her newborn young on her back for their first couple of weeks.
If someone is stung, Poison Control at 1-800-222-1222 can advise on what to do. Get medical care right away if a young child is stung or if anyone has trouble breathing or unusual eye movements.
What bark scorpions eat and how long they go without food
Bark scorpions eat live insects and other small arthropods, mainly crickets, cockroaches, silverfish and spiders around homes, and sometimes other scorpions. A bark scorpion mostly hunts by waiting in one spot and grabbing whatever walks past, so it does not have to travel far to eat.
Scorpions have a low metabolic rate and can go weeks, often months, without eating. Much of their water comes from their prey. That slow metabolism is a big reason they are hard to control, since a scorpion can stay tucked in a wall void for weeks without coming out to hunt.
Fewer insects around the house give scorpions less reason to stay. Outdoor lights draw crickets and other insects after dark, and yellow or warm-colored bulbs attract fewer of them than bright white ones. Our cricket control and cockroach control services reduce the insects that keep scorpions fed.
When scorpions are most active in the Phoenix area
Scorpion activity in the Phoenix area follows nighttime temperatures. Bark scorpions start moving in spring as nights warm up, and activity stays high through the summer. Monsoon storms, most of which fall between July and September, flood their hiding spots and bring out the insects they eat. Many homes see more scorpions in late summer, which our article on monsoon season pests covers in more detail.
Activity drops off in late fall. Through the winter, bark scorpions mostly stay put in sheltered spots, though a few turn up indoors where walls and attics stay warm. Winter is a good time to replace door sweeps and clear out woodpiles before the next season starts.
Why sprays alone fall short against scorpions
Bark scorpions are not immune to pesticides. The products used in professional pest control kill them, but a scorpion has to contact enough product first, and its habits work against that. It spends the day in cracks a spray does not reach and stands high on its legs, so little of its body touches a treated surface. Baits do not help either, because a scorpion only eats live prey.
Arizona weather adds to the problem. Heat and sunlight break down exterior treatments faster here than in milder climates, so they need renewing on a regular schedule. Spraying baseboards indoors only reaches scorpions that have already come inside, while the ones living in the block wall and rock beds stay untouched.
Our technicians treat the places scorpions shelter: the hollow cells of block walls, gaps under cap blocks, the weep screed line, and cracks along the foundation. Regular visits keep that treatment fresh through the warm months, and the scorpion control page explains each step of the service.
How sealing and yard cleanup keep scorpions out
Sealing keeps scorpions outside once treatment has brought their numbers down. The gaps we find most often are worn door sweeps, garage door seals that no longer meet the slab, openings around pipes and torn window screens. Hiding spots near the house matter as much as the gaps, since every pile of rock or lumber gives scorpions a place to spend the day a few feet from a door.
Much of this work is within reach for a homeowner:
- Replace door sweeps and weatherstripping wherever daylight shows around a closed door.
- Swap out the garage door's bottom seal once it cracks or stops touching the floor.
- Caulk gaps around pipes and air conditioning lines where they enter the wall.
- Repair torn window screens and damaged attic vent screens.
- Store firewood and spare pavers off the ground and away from the walls.
- Have dead fronds trimmed from palm trees, and cut back branches that touch the roof.
How to check for scorpions with a blacklight
Scorpions glow blue-green under ultraviolet light, which makes a blacklight the easiest way to see how many are around a house. Compounds in the outer layer of the exoskeleton cause the glow, and researchers still debate what purpose it serves.
A handheld UV flashlight is enough. About an hour after dark on a warm night, walk the base of the house, the block walls, the edges of rock beds and the pool equipment. Wear closed-toe shoes and keep hands away from anything that glows. Several scorpions on one stretch of wall point to where they are living, which is useful for your technician to know.
What regular scorpion control in Arizona looks like
Our usual recommendation for a house with steady scorpion activity is monthly or bi-monthly service, and the night inspection decides which. Most homes notice fewer scorpions within a few weeks, and sightings are usually still falling two or three months in. A house next to open desert may still see the occasional scorpion after that. Between visits, our re-service guarantee applies, so if covered pests come back before the next scheduled service, we return and re-treat at no extra charge.
Platinum Pest Management offers a free inspection and a free written quote, and the pest control plans page lays out each schedule we offer.
Frequently asked questions
Are Arizona bark scorpions immune to pesticides?
Bark scorpions are not immune to pesticides, and the products we apply do kill them. They are harder to control than most pests because they spend the day in cracks and wall voids, can go weeks without eating and do not take baits. Sealing gaps and clearing out hiding spots help treatment work better.
How often should an Arizona home be treated for scorpions?
For homes with active scorpion problems, Platinum Pest Management usually recommends monthly or bi-monthly service, at least through the warm months. The right schedule depends on the lot, especially how near it sits to open desert, and on the number of scorpions a night inspection finds. Our pest control plans page explains each option.
Why do scorpions end up in the bathtub?
Bark scorpions climb walls and ceilings and sometimes drop into tubs and sinks. The smooth sides are too slick for them to climb back out, so they stay there until someone finds them. In most cases the scorpion fell in from the wall or ceiling and did not come up through the drain.
Can I do a blacklight check for scorpions myself?
Yes. Any handheld UV flashlight will work. About an hour after dark on a warm night, check the base of the house, block walls, rock beds and tree trunks, and wear closed-toe shoes. If several scorpions turn up in one area, tell your technician so treatment and sealing can focus there.
Will scorpions ever be completely gone from my yard?
Probably not, if the house sits near open desert, washes or preserve land. New scorpions keep arriving from outside the yard, so the realistic goal is low activity outdoors and few or none inside. Regular exterior treatment and sealing get most homes there, and our re-service guarantee applies to covered pests that return between visits.