My 20 foot arborvitae has brown tips, mostly low and on one side, similar to the symptoms described for fungus, although I cannot see any fruiting bodies. In addition, over the entire crown there are sap globs on twig tips. I see no sign of cotton structures associated with adelgids. The brown tips are starting to show up on the rest of the tree but very scattered. There is a cutter pipe next to tree but has a 10 foot pipe attached but some gutter overflow occurred this winter. Do I have a disease problem, an insect problem, or an environmental problem, or all? Thanks Dan.
Just based on your description, I would not suspect an infectious issue, but rather an environmental one. If possible, can you send a photo showing the entire plant with the brown area visible on that one side. Be sure the image is in focus by reviewing it on your computer before sending. Also try sending a closeup of the brown twig tips too. A couple of questions in the meantime---How long has the shrub been planted? Has anything been sprayed/applied on or around the shrub? Has the browning area gotten any larger or worse?
A picture may be useful to help solve this one.