I don't vote for viruses, it's not coherent, as old leaves and brand new a affected but not those in the midle.
Also, the fact spots can be seen only on one side is mort a sign of a fungus.
(It doesn't mean there's no virus, but we can't prove it this way, very little signs can hint an effective presence).
Check if there's nothing sucking you leaves, it may be one of the causes. And I'd go for a fungicide.
If you see the affected leaves turning bad, don't be afraid to cut those. (sterilize tool, dispose immediatly of the leaf and clean you hands before and after, put cinnamon powder on the cut.)
|