Question

The only beauty in finding a leaf problem with a plant is that it is quite mobile so you can just pull off one of the infected leaves and head down to your local gardening store to show it to one of their specialists.

Is it getting enough sun? Are you growing it in compost, or a Grow-Bag? Feed it Tomorite feed, water morning and evening, give it plenty of sun (har, good luck with that!) and check for under-leaf parasites.