My elderly relative has asked me to do a research on her cactus which has recently got these dark spots:
I poked them and they are dry and hard when you touch them. There is no liquid or mush. They are only present on the spots the needles come from. Otherwise the cactus is looking healthy and it’s constantly growing.
I don’t know what kind of cactus is this. I bought it for her at local grocery store 4 years ago.
Should I “amputate” these spots?