Thanks for your question.  It has been assigned to me.  I assume this is a potted plant.  If so, do you keep it outside during the summer season and then bring it in once temperatures cool?

I would like to receive a picture of the entire potted plant.  If it is in a container, what kind of drainage exists.  Also please tell me some more information about it.  How long have you had it?  What kind of watering schedule do you follow?  How much direct sunlight does it get each day?  Are you seeing this leaf browning for the first time, or has it appeared at various times in the past?

Put a couple pieces of white paper under the plant.  Give the plant a couple of good shakes.  Are there any small insects that fall down onto the paper?  If so, try to take a picture or two of what you see and send to us.

Many thanks for doing this.  I'll look forward to working with you to solve this problem.