I'd also check for spider mites. When there's a really bad infestation, you
can see the fine webbing. Otherwise, as David Bockman said in a earlier
post, check the underside of the leaves for tiny black specks -- this also
can be a good indication of spider mites.

In any event, whether aphids or spider mites, an insecticical soap product
should knock them out. Follow the label recommendations and be sure to
treat the underside of the leaves.

Good luck,
Suzy O, Zone 5, Wisconsin

"Gofer" wrote in message
...
Dear members,
I live in Israel, in a penthouse, full of sunlight. I have many pots with
various plants: palm trees and citrus, seasonal flowers, like penies and
gotetia, and vines like passion frut. Some month or two ago, just between
the spring and the summer, many of my plants got discoloration on the
leaves: the smooth green leaves started to yellow, but not in a smooth
way,
but rather in an inhomogeneous way. I am attaching a photograph of a leaf.
If you know what might cause the change, and what is the cure, please
help.
Yours,
Y. Gofer