Garden Pests and Diseases: What is this on my Christmas Cactus?, 1 by greenthumbnails

greenthumbnails wrote:
This past season I noticed this rusty colored thing on my Christmas Cactus that does not rub off. I believe it eventually eats through the plant leaves over time. I found some raised blistered areas elsewhere on the leaves and believe that these then turn to that rust color. Anyone know what this is and how to deal with it to save the plant? I recently mixed up some Safer Brand 3n1 pesticide and sprayed the leaves in the early morning. I have relocated the plant to the outdoors for now.