Question
I have the same problem as the question asked  on 5/3/2006/.
I also live in the same area(delaware). My hollies have a black leaf problem. The leaves do Not turn yellow and fall off. I.ve had this problem foe several years and have treated them with pesticides and fungicides, but have only had partial success. aphids? haven't seen any. Any help would be appreciated. Thanks in advance.

Answer
It sounds like either aphids or scale insects-both suck the plant juices and excrete honeydew and a black sooty mold grows on the leaves. Check and see if the leaves feels sticky if so then contol the insects and the black sooty will wash off over time. Scales are small and sometines overlooked as just "bumps" on the twigs.  Since the leaves are not turning and dropping I would lean toward the sooty mold just coating the leaves and not some disease getting into the leaf surface. The black itself is not a problem for the health of the tree and may take several rains to completely wash off and some may not all the way wash off. If the new growth is green you have solved the problem.