Depending on the size of the tree, repeated blasting of the foliage with a
water jet will work wonders.

Dave

"peter" wrote in message
...
Is there anything I can buy from home depot that can get rid of spider
mites
and is safe to use on arborvitae?

Last time I picked up a bottle of spider mite chemical, I later found the
instructions said not to use it on arborvitae.