This is one of the "cement" cacti I first posted about. I believe it is a notocactus, not positive. Was doing great after I re-potted it, but now there are black, oozing spots on it! First appeared two weeks ago, not brown, do not spread, and seem to be perfectly circular! any ideas what ails it and what to do about it??
Too thin for a Notocactus, looks more like one of those columnar cacti that I know nothing about. The one at the right edge in picture 2 is a Notocactus (claviceps? leninghausii? something else?). If you are lucky, the black spots might heal by themselves, but it looks like one of these bacterial/fungal infections that kills the plant. I would have isolated it from other plants until I saw how it developed (this is one reason why I never put more than 1 plant in the same pot). If it spreads, throw away the plant. Or cut off the top and re-root.
Something else you might want to consider. You can cut the black spots out with a very sharp sterilzed knife to help keep any bacteria from spreading, then apply a household bleach solution (10 % bleach) to each area you cut for the same reason.
thank you both so much. i will isolate and cut spots out as well. if anybody has any other ideas, I would be appreciative to hear them.
