disease is most commonly seen on Austrian and black pines 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.
pathogen infects and kills current year's shoots. When the infected
needles are l/2 to 3/4 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.
problems can cause similar dieback and tree decline. Winter drying,
drought, injury from weevils, pine-shoot moths or tip moths, as
well as some needlecast diseases caused by other fungi may cause
damage similar in appearance to tip blight.
courtesy of the Minnesota Department of Natural Resources Archive,
Minnesota Department of Natural Resources
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 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
during the winter in the infected shoots, bark, cones or needle
litter beneath the tree.
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 inch deep holes in the soil on 12-20 inch centers
under affected 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.
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.
Do not shear or prune infected trees during wet weather, as spores
released at this time may be carried from tree to tree on pruning
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.
from Stephen Nameth and Jim Chatfield, Ohio State University Extension,