Disease or pest problem on potted mango

Hi everyone. I was wondering if anyone has ever seen this before. I have 2 potter Glenn Mangos I've had for a couple of years now. Only one has ever flowered and it only happened once, and died off so no fruit. And my stems are beautiful green when new and then begin to get covered in these little white waised bumps until they become so numerous they look almost like bark.  At first I thought that must just be how the new growth becomes woody, but now I think it must be a disease or pest of some kind.  Any help would be appreciated!