Question
The leaves on my lilac bush are turning white or the surface of the leaves look white & anemic, what  is wrong?

Answer
Beverly:
Lilacs are susceptible to a fungus disease called powdery mildew. This may be what you are describing.  This fungus grows mostly superficial on the leaves of the host plants.  The disease on the leaves looks like white "fuzzy" patches or splotches on the leaves. You can use your computer and search for images of this disease on lilacs using "Google".

I am attaching a link to a bulletin that I prepared on this disease that can affect many ornamentals. (This file is a pdf, so you will need a small program (free) called Adobe Reader on your computer to read it).

http://www.uaex.edu/Other_Areas/publications/PDF/FSA-6113.pdf

It is one of the most easily recognizable plant diseases.

If after looking at some photos on the web and this bulletin your leaves look different, you can send me a closeup photo of a leaf or two and I will be happy to take a look.  Be sure to review your image on your computer first, before sending, to be sure it is in focus.

Regards
Steve