I've had a great deal of experience dealing with scorpions thanks to idiot developers shipping in palm trees from Arizona, complete with the Striped Tail Scorpion
(Centruroides vittatus) and the Arizona Bark Scorpion (
Centruroides sculpturatus) attached.
In a place where scorpions are endemic, there are two things to start with outside the actual home. First, get rid of all the places adjacent to the home where they or their prey might hide. Second, obliterate the entire yard of their prey, I use Bayer
BioAdvanced 2-way Formula because it will also kill scorpions it gets on. Scorpions that cannot find anything to eat will leave your property eventually. Before they do, they will become much more evident at night as they try to find food. I'll get back to that point later.
Here's another key, most if not all of the persistent bug sprays don't work well on scorpions. It has to do with the way they interact with the environment. Roaches are continually tasting the ground, so they get poisoned. Scorpions don't do that. One thing that will slow down scorpions (eventually) is
diatomaceous earth. Spreading that around the foundation deals with almost everything with six or eight legs that crawls. It breaks down the coating that allows the bugs to retain water, and they die of dehydration...eventually.
When it comes to what is effective when you spray directly on one,
Raid Max Spider/Scorpion is the #1 tool for one shot stops. It is rare that even large scorpions getting a hit from it move more than three feet.
Terro scorpion killer also kills them (eventually, after a lot of walking backwards) and leaves behind some kind of gritty deposit that may discourage others.
Harris Scorpion Killer is supposed to be a persistent killer but I and others in Vegas have our doubts. If sprayed directly the Harris product takes its time killing compared to
Raid Max.
Ortho Home Defense sprayed directly on small scorpions appears to work well. I think it will eventually kill larger ones as it certainly causes a strong reaction, but I usually lose patience and apply another method to speed them on their way.
When it comes to getting the spray on them directly, going out at night with a powerful UV light is the only way. Don't forget your orange tinted goggles, UV light is bad for your eyes. Scorpions hide in cracks and under leaves with just the tips of their pincers showing, so watch out for those shining in the UV light. Sometimes they will sit in plain view on walls, warm rocks, and kerbstones. Those are easy kills. Finding a female carrying young is bizarre as the young ones do not fluoresce, so you see the adults pincers, legs and tail but nothing else. Drown the lot in Raid Max to knock off a complete generation.
Professional bug guys will come out at night and spray your yard, walls, and outside of the home with cedar oil. It drives the scorpions out of cover where they can be collected using long tongs. They shove all they can find in a big jar and kill them en masse when done. Watch out if your neighbor has this done, as the scorpions in the yard walls will often come through onto your side. This happened at my house, and I killed about nine on the common wall in one evening.
It is a measure of my success in controlling these buggers that we now hear crickets in the yard. When I first moved to this house, neither they nor the roaches had a chance because of the scorpions.
