Tip blight of juniper is a common problem and is typically caused by one of two fungi: Phomopsis juniperivora and Kabatina juniperi. The usual symptom is browning of the scales/needles on the tips of branches. Tiny black fruiting bodies (spore structures) of the fungi form in a grayish area at the base of the browned section.
Recently (in late fall), scattered tip browning was noticed on this juniper growing in a home landscape near the road. Closer inspection revealed tiny black fruiting bodies in the needles, not just in the area at the base of the needles.
A microscopic look at the spores confirmed Sphaeropsis (Diplodia) tip blight. This is an important disease of two- and three-needled pines and is found on other host trees or shrubs when they are already stressed by other problems that could be environmental or other pests and diseases. In addition, there is usually an infected pine nearby that serves as a source of spores.
For juniper, control measures would include good cultural practices to minimize stress and avoidance of the use of de-icing salts nearby. Juniper has only a moderate tolerance for salt. If a heavily infected pine is nearby, that could be removed if it’s in bad shape. On pine, other options include pruning out dead and dying twigs, branches and cones during dry conditions, clean-up of fallen twigs needles and cones, good cultural practices and fungicide sprays when buds swell in spring, again when new ‘candles’ are about half elongated, and a third application as needles emerge from their sheaths. When using pesticides, always read and follow label instructions carefully and apply only to plants and problems listed on the label.
By J. Allen