Mealy bugs can secrete themselves in cracks and crevices and exist in a dormant state for a very long time. Here’s a snippet from the AzaMax website that explains it well:AzaMax is an all-natural, OMRI certified broad spectrum pest control product that can be applied systemically or as a foliar spray. After dumping the infested plants, I thoroughly cleaned the terracotta bowl, filled it fresh soil, placed some rocks I brought home from our recent trip to the Oregon coast , and finally added seven sempervivum babies I had growing. They like to eat the honeydew produced by the scale insects and leave behind a sooty substance instead. Learn a simple way to get rid of them that is safe for the succulents!