Diplodia Tip Blight
Diplodia primarily affects Austrian pines. The disease causes new needle growth to die.
What Is It?
Previously known as Sphoeropsis Tip Blight, Diplodia Tip Blight is a commonly occurring fungal disease of stressed conifer (evergreen) trees.
Diplodia Tip Blight (DTB) can affect all species of pine trees. The disease has been seen in trees across the entire United States as well as across the world. There are no species of pine tree that are resistant to DTB and Austrian, Scots, and Red Pine trees are the most susceptible to the disease.
How To Identify:
The first sign of DTB is brown needles at the tip of the current year's growth. This usually occurs in the lower branches of the tree. The number of blighted needles will increase over time until the host branch is killed. Beyond the needles, DTB can cause disfiguration of twigs and, upon close examination, cankers can be found in these disfigured branches.
Sphaeropsis sapinea, the fungus which causes DTB, lives year round in dead needles, twigs, and cones located either on the infected tree or on the ground. Fruiting bodies mature during the spring out of which ooze spores that are scattered by wind, rain, animals, or humans. These spores land on new, young growth where they enter the tree causing the browning of needles to begin within only a few hours.
If Left Untreated:
Many species of evergreen needles will only live for 3 to 4 years before dying and falling off. Because DTB causes the new needle growth to blight and fall off, no new needles can form on a branch. Eventually the older needles die off along with the newer ones and you are left with a dead branch.
To treat for DTB, we treat the soil around the tree with a fertilization treatment, and the trunk of the tree is injected with a fungicide. This treatment will last for three years.