"Paul E. Lehmann" wrote in message
. ..

I have six Arborvitae planted in a row with about
10 feet betteen trees (Central Maryland). They
are about 5 years old and are doing well except
for one tree that developed dried needles on one
side of the tree and rolled up needles similar in
shape and appearance to a cacoon made by
butterflies. There does not appear to be
anything inside, however.

I started spraying the tree with the same thing I
am spraying my vineyard (Dithane, Sulphur,
Penncop, and Seven). The condition has not
gotten worse and possibly it is showing some
signs of recovery.

Any idea on what this condition is due to?

Sounds like bagworms...
http://tinyurl.com/yr39m8