Suddenly my old wonderful cactus had new growth dying. I cut off the first bad part and it seemed to heal and do fine. Then all the other new growth has turned gray and is dying. Doesn't seem like over watering. Can cactus get aphids or other critters that would cause this? I was getting ready to repot, but decided to ask all you experts first. It's in a clay breathing pot and hasn't been repotted for several years. They have small roots don't they? Thanks for any help. While unnamed, it does feel like member of the family.