[Cynthia, Prescott, AZ]

You need to do surgery and do it now. Use a sterilized tool, and be sure to give at least a 1/2 in clearence of good tissue where you cut, then spray the cut area if you have some of the Phyton made up. then dust with the cinnamon or sulfur. The cut edge will turn brown for an 1/8 inch or so, and that is no problem. But if you see one or two spots where the discoloration is clearly starting down the leaf again, cut a second time with more tissue as a buffer. Hopefully this wont happen. But, you must stop this from progressing, even if you loose the entire new growth. Keep us informed how this goes.