Michigan State University Extension
Ornamental Plants plus Version 3.0 - 00001123
11/12/99
PINUS DISEASE PROBLEMS
Armillaria Root Rot kills trees by girdling them at the soil
line. Infected trees will show yellowing then death of the
needles. Other symptoms include patches of resin on the bark
at the root/trunk junction. White fungus patches form under
the bark in the infected area. Stressed trees will be more
susceptible.
Pine wood nematode causes the needles on entire tree to turn
brown. Wound on tree infected with the nematode will not
exude resin. Scotch pine is particularly susceptible. There
is no control and infested trees should be burned or
chipped.
Tip blight caused by Sphaeropsis sapinea (Vis. 1) is common
on Austrian Pine. The new growth turns brown and the branch
is stunted. Black fruiting bodies may be found on the dead
needles. The fungus may attack the branches and form
cankers. When the canker girdles the stem, the portion of
the stem above the canker will die.
Needle blight caused by Dothistroma pini infects Austrian
Pine. Dark, slightly swollen bands form on one year old
needles in late summer. The part of the needles beyond
the band dies. Severely infected trees look thin. Black
fruitbodies will form in the dead tissue.
White pine blister rust attacks White Pine and uses
currant or gooseberry as an alternate host. The first
symptom is usually a patch of brown bark surrounded by a
yellow border. Blister appear in the infected bark and
release spores. Eventually, the portion of the tree above
the canker dies. The disease is favored by cool, moist
weather in August and September.
The needles droop if the roots can not supply adequate
amounts of water.
White and other pines may be injured by salt if growing
near roads. Austrian Pine is the most salt tolerant pine.
Pines with roots growing in drain fields receiving
softened water may be injured.
Lophodermium needlecast causes browning of needles,
especially on Scotch pine. The fungus causes brown spots on
the needles which then eventually die. The brown needles
should occur first on the bottom of the tree. These will
fall off and the tree may try to send out new growth giving
it a tufted appearance.
Related information.
Pesticide Recommendations
Pine Needle Rust
White Pine Blister Rust
Cankers
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This file was generated from data base ZZ on 01/19/00.
Data base ZZ was last revised on 11/12/99.
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