Twig Blight of Juniper List of files and visuals associated with this text. Twig blight of juniper is caused by Phomopsis juniperovora Hahn, Cercospora sequoiae var. Phomopsis twig blight also may cause a more rare dieback of branches of eastern red cedar, arborvitae, taxus, fir, Douglas fir, larch, cypress, jack pine, hemlock, true cedar and false cedar. Symptoms include the dieback of the tips of branches that are equal to or smaller in diameter than a pencil.
Infected foliage becomes pale, then reddish brown, then turns brown or ash-gray after death.
To confirm your diagnosis of Phomopsis as the cause of twig blight, scrape away the thin bark until you reach living wood. There should be a sharp line between discolored dead wood and healthy wood. Also, look at the base of the ash-gray scale needles for small, black fruiting bodies. The fruiting bodies form the spores that cause new infections. In wet weather, spores ooze from the fruiting bodies and splash onto new foliage.