By Ifa
Italy 
my clementine tree has brown spots on the back of some Leaves..what is this and what can I do?
11 Apr, 2013
By Ifa
Italy
my clementine tree has brown spots on the back of some Leaves..what is this and what can I do?
11 Apr, 2013
You may just have an attack of alternaria (possibly A. alternarta). It is a fungal disease of plants.
It is not possible for me to say definitely without a photo. Can you post one?
If you want a really heavy scientific description of this go to http://www.phadia.com/ko/3/ImmunoCAP-Allergens/Molds-and-other-Microorganisms/Allergens/Alternaria-alternata-/
If you can't post a photo then I suggest you should spray with Bordeaux mixture (copper sulphate compound) and hope for the best.
Sorry to sound vague but it is very difficult from just a vague description.
11 Apr, 2013