Troubled Opuntia Robusta

[Hobokin]

I’ve got an opuntia robusta that is suffering from some beige spots. It started out on just a few paddles but has spread quite a bit. It’s now at the point where removing all of the affected paddles would decimate the plant, which I am trying to avoid.

Interestingly, there is another robusta just a couple of yards away that is completely unaffected.

Is this a fungus? Any suggested causes and/or remedies?

Thanks in advance.

opuntia-robusta-small.jpg (131.25 KiB) Viewed 727 times

[mikethecactusguy]

scale..