I bought a yellow gallon container from Lowes or Home Depot that works against scorpions, spiders and mites and it's worked great for us. Use it indoor and outdoor.
HARRIS Scorpion Killer, Liquid Spray with Odorless and Non-Staining Formula (Gallon) https://www.amazon.com/dp/B00E8OY1TA/ref=cm_sw_r_apan_glt_fabc_H6762H91E3BVM0ZC0JR6?_encoding=UTF8&psc=1
Also I would purchase a blacklight or two.