Diplodia Tip Blight of Pine
Tom Creswell, P&PDL Director, Plant Disease Diagnostician
Austrian pine is frequently attacked by Diplodia
(Spaeropsis) tip blight, although the disease can also be found on
Scots, mugo and red pine. Diplodia tip blight on Austrian pines
in the landscape typically produces symptoms on trees after cone-bearing
age. Stressful site and environmental growing conditions
such as drought predispose 2-needled pines to infection by Diplodia.
The first symptoms on Austrian pine arise in late
April through early May. Needles and shoots are stunted and killed
very quickly and shoot tips are often quite resinous.
Infections year after year can lead to the death of older needles
as well as branch dieback and ultimately tree death. Branch
cankers are often coated with exuded resin, which dries and leaves
white patches and droplets on the bark.
Avoid using Austrian Pine in drought prone situations
and make sure existing trees get adequate water during dry summer
periods. Prune out and destroy dead and dying branches promptly.
The best prevention for this disease is to keep the trees growing
as vigorously as possible. Invigorate the root system, as recommended
in the publication (HO-140) available for download at http://www.hort.purdue.edu/ext/HO-140.pdf
The lack of effective control measures on large Austrian pines
infected with Diplodia and other fungal needle blights have caused
many to forgo using Austrian pine in the landscape in favor of
For more information on ID and control of Diplodia tip blight go to:
Figures 3, 4 courtesy of Christine
Engelbrecht, Department of Plant Pathology, Iowa State University
Click image to enlarge
Figure 1. Mature Austrian pine trees
with dead lower branches
due to Sphaeropsis tip blight.
Figure 2. An elongating shoot which
was killed by Sphaeropsis tip blight
(Note stunted dead needles).
Figure 3. Diplodia tip blight on an Austrian pine branch.
Figure 4. Black reproductive structures of the Diplodia fungus on