I have 16 blue tip Juipers all are about 8 feet tall and are 8 years old. I noticed this week that on 9 plants the needles were turning brown. So far it\'s the interior that is turning brown. The outside of plant is fine. I water them on a drip system. Any help would be deeply appreciated
Sorry you haven't gotten any help for this. I use to work the helpline at the Rutgers Extension Center here in NJ and it was usually very difficult to diagnose evergreen problems since with most issues the needles just turn brown without many other hints such as say wilting or scorching or spotting like you would see with deciduous plants. Many things cause needles to brown and often it could just be lack of sunlight. Many evergreens lose their inside needles naturally or on a side where they face a wall or another plant.
I see you have large rocks on the ground and I would check the environment below that, making sure the roots don't get too hot, too wet or too dry as drought and overwatering cause problems.
Have you seen UC's web page on Juniper? Look at the list on the right side of the page and click on the issues that should be possible issues in your local.
http://www.ipm.ucdavis.edu/PMG/GARDEN/PLANTS/juniper.html
Then read through this Fact Sheet put out by Clemson Cooperative Extension even though it is North Carolina. It goes through quite a few issues that affect Junipers in a little more detail compared to UC's Juniper page.
http://www.clemson.edu/extension/hgic/pests/plant_pests/shrubs/hgic2056.html
You could bring in a sample to the extension center. Make sure the sample includes the problem area transitioning to a healthy area. They should have a microscope to see things that you might not be able to such as mites. They might not be able to be specific about blights and such unless the disease has unique clue about it.
Sorry I can't be of more help but hopefully this gives you something to work with.
