Arborvitae Diseases

Informational table showing disease name, symptoms, pathogen/cause, and management of Arborvitae diseases.
Arborvitae Diseases - Articles

Updated: August 14, 2017

Arborvitae Diseases
DiseaseSymptomsPathogen/CauseManagement
BranchletThe oldest branchlets turn brown in autumn and fall off.Normal browning.Branchlets rather than scale leaves are shed in autumn as a normal part of the plant development.
Kabatina twig blightTips of one-year-old branches die and turn brown or ash gray. These remain on the shrub for many months. Larger branches can be invaded and girdled. On the dead tissue where it meets the still-living wood, small, black, pimple-like fungal fruiting structures form. Microscopic examination reveals oval, colorless spores. See Phomopsis below.Kabatina thujaePrune and destroy infected twigs and branches. Both Kabatina and Phomopsis twig blight can occur on the same plant. Apply a fungicide to protect plants.
Pestalotiopsis tip blight)Twig tips turn tan to brown in color and have black, pimple-like fungal fruiting structures dotting their surface.Pestalotiopsis funereaProtect plants from winter injury, drought, and other stresses. Apply a fungicide to protect plants.
Phomopsis twig blightTips of branches die and turn brown or ash-gray. These remain on the shrub for many months. Larger branches can be invaded and girdled. On the dead tissue where it meets the still-living wood, small, black, pimple-like fungal fruiting structures form. Microscopic examination reveals both oval and long, thread-like colorless spores. See Kabatina above.Phomopsis juniperovoraPrune and destroy infected twigs and branches. Both Kabatina and Phomopsis twig blight can occur on the same plant. Apply a fungicide to protect plants.

Prepared by Gary W. Moorman, Professor of Plant Pathology