Cyclamen

[abigri@iaw.com]

Any seasoned Cyclamen grower will probably know this, but still here's my
question:

What is causing very small purple spots along the smaller veins of Cyclamen
leaves. The spots are not necrotic, they are irregularly shaped and
slightly sunken into the top of the leaves. The spots appear mainly on the
older leaves of a plant. The spots are less than 1/10 of an inch wide, but
they are sometimes up to 1/5 of an inch long

I have been observing these spots on several crops now. They seem to be
worse on certain varieties, while other varieties do not show them at all
under identical cultural conditions. 

Any help would be appreciated.

Albert Grimm