Hi all. I have battled with a handful of Junipers (Sargent Junipers specifically) where the foliage starts to become discoloured, pale and then light brown and eventually dies back. It usually start on the lower branches (tips of the foliage first) and slowly moves up the tree. This started in spring and continued through summer. Suspecting tip blight, I treated with Mancozeb as well as other fungicides. This did not help so I cut off all the infected foliage but the issue just kept occurring as if it were an incurable cancer… with some trees, I eventually cut off so much that there was not enough foliage to support the tree. Some experts suggested that it might be spider mite, but I found no sign of mites. Here are some pics.
I’ve checked the roots and can see no issue there. They are all planted in a mix of Akadama and Pumice. Below is another picture of a different type of foliage attack, not the same as the trees above. Again on Sargent Juniper.
Any ideas as to what this could be and possible treatment?