Q.Does My Crown Of Thorns Have Bacterial Leaf Spot?
After reading Mary Ellen Ellis’ post on bacterial leaf spot on crown of thorns, I’m, naturally, wondering if that’s the trouble with my plant. This plant was given to me by my mother about 24 years ago. It has always looked beautiful and bloomed wonderfully. About 8 years ago it was repotted with very well draining, somewhat sandy soil. It did just as well or better. I never watered it very much and always had it sit by a sunny window. Within the last 1-2 years, it gradually began to show yellowing of leaves and later brown spots but it still bloomed like crazy. I tried all suggestions I could find at the time including repotting, making sure it was not watered too much, and then a fungal treatment. Now, which is 4-6 months later, it is looking worse and has begun to limit blooming. It was only with your post that I looked at the spots more carefully for the angular shape. I see on a few leaves that the brown area seems to begin on the veins. I am attaching a picture to see if you can confirm. Is there anything that I can do to save it? Your help would be so much appreciated. It has some sentimental value to me or perhaps I would already have come to terms with it having lived a long, good life! Thank you (in advance).

Certified GKH Gardening Expert
It could be, but there are many look-a-like pathogens. The best thing to do is to contact the local extension department for a diagnosis by the pathology lab. Also ask them to recommend a fungicide.
https://www.gardeningknowhow.com/extension-search
https://extension.umd.edu/resource/bacterial-leaf-spots-indoor-plants