This looks very suspicious for Pseudomonas.
I would cut the leaf off leaving about 1-2 inches of healthy tissue. Anytime disease is isolated I perform surgery preferable over using chemicals.
This is much easier on the plant and more effective in getting rid of the problem than hitting it with physan or fungicide as the rest of the plant looks healthy
Another reason to cut: Pythium can look just like pseudomonas...and that HAS to be cut.
My only other thought is sunburn which is not my #1 "choice".
Hybrid Mode
