Beginner Gardening: Spots on the leaves of growing Salvia, 1 by pfcosta

pfcosta wrote:
Brown spots on the leaves of a young growing Salvia farinacea (cloned - cut from older plant). Plant has been growing very well. Image shows spots that developed in the past four days.
- spots are visible on either upper and lower surface
- a couple of young leaves now show necrosis at the tip
- neighbour pots with growing salvias appear to develop same symptoms, although at early stage

Fungus? Bacteria?
Thanks for help.

Pedro F Costa