Insect and Disease Fact Sheet Compliments of
New Century 
1-877-79TREES
Diplodia Tip Blight of Austrian, Red and Scotch
Pine
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Susceptible Pines This
disease is most commonly seen on Austrian pine and some of the other two and
three needle pines such as red pine, Mugho pine and Scots pine. It is found
more uncommonly on white pine, spruces and other evergreens. The fungus
commonly attacks mature trees that have been under stress from drought, root
restriction or other planting site problems. It can also be a problem in
young, rapidly growing nursery or Christmas tree plantings. Symptoms The
pathogen infects and kills current year's shoots. When the infected, current
season's needles are ½ to ¾ expanded, they turn yellow, then brown as
they die on individual branch tips. A close look at the bases of the dead
needles may reveal tiny black, fungal fruiting bodies emerging from the
needle surface. Repeated infection over several years causes the ends of
affected branches to have a proliferation of shoots. If left unchecked the
disease can eventually kill mature trees. Girdling cankers can be formed if
the pathogen infects wounds on the stem. Other
problems can cause similar dieback and tree decline. Winter drying; drought;
injury from weevils, pine-shoot moths or tip moths; and some needle cast
diseases caused by other fungi may cause damage similar to tip blight. |
This Scots pine shoot has been killed following
infection by the tip blight pathogen.
Tip blight on Austrian Pine. |
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The lower left portion of this pine is diseased with
tip blight. It often begins on lower
branches. |
Causal Fungus and Disease
Development Tip
blight is caused by the fungus, Sphaeropsis sapinea, once known as Diplodia
pinea.
Spores of the fungus develop in the black fruiting bodies located at
the base of infected needles and other affected plant parts from spring
through fall. They are spread about only during periods of rainfall. Pine
shoots are particularly susceptible to infection in early spring. Developing
cone scales are also commonly infected, although they are not damaged.
Wounds, such as those made by hail, shearing, or insects (weevil or
spittlebug feeding) also serve as entry points for the fungus. The fungus
survives over winter in the infected shoots, bark, cones or needle litter
beneath the tree. |
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Control 1.
Trees should be kept in good vigor with regular maintenance, deep watering
during droughts, fertilizing, control of insects and vertical mulching to
open up the soil in the root zone. Vertical mulching can be done to improve
landscape soils. Vertical mulching will lessen damage due to excessive water, preserve necessary aeration during wet
periods, allow sub-soil water penetration during dry periods, and promote the
formation of fine feeder roots. Drill one or two inch wide, 18" deep
holes in the soil on 12-20” centers under infected trees near the drip line
of the branches (where fine feeder roots are located). Fill holes with a
mixture of equal parts of peat and a coarse aggregate such as pumice or calcined clay particles. 2.
Remove previously blighted shoots. Since many spores are produced on cones,
removal of previously blighted shoots probably does not decrease spore
numbers appreciably. However, it does
serve to make the tree look better and may increase its vigor. 3.
Do not shear or prune infected trees during wet weather because spores
released at this time may be carried from tree to tree on pruning tools.
Close-up of pine needles with tip blight. |
Finding the tip blight fungal fruiting bodies at the base
of dead needles confirms its presence.
Fungal fruiting bodies on pine cones. 4.
This disease can be partially controlled with fungicides. Attention must be
given to protecting the new spring growth of the trees from bud swell to full
candle elongation. Make first application just prior to bud break and make
two |
or more additional applications at 10-day intervals. It is important to
get the first application on the trees before any bud sheaths have broken. If bud
sheaths have broken, spraying with fungicides is a waste of time and money.
Information obtained through the Ohio State Extension Factsheet HYG-3041-96
Insect and Disease Fact Sheet Compliments of
New Century
1-877-79TREES