Leyland cypress is a tree that shouldn't be sold in most parts of the west coast. It is susceptible to Siridium (spp) a wind blown fungal disease that will eventually kill the cypress, there are no effective fungicides. You can try pruning off the infected branches, however even if you remove the infection it will be back. Save yourself some heartache, get rid of the tree and replant with deodar cedar, incense cedar, Italian stone pine or Arizona cypress.
