| Disease |
Symptoms |
Pathogen/Cause |
Management |
| Cyclaneusma Needlecast |
Needles on Scots and Austrian pines yellow and
have dark-brown bands from September through December the year
after infection or April through June two years after infection.
The brown bars become filled with a tan fungal fruiting structure
which opens wide under very moist conditions. |
Cyclaneusma minus |
Space plants and control weeds for good air circulation.
Apply chlorothalonil or triadimefon + chlorothalonil first in
mid-March and again early May, mid-June, mid-August, and mid-October
to protect the needles since they can be attacked any time the
temperature is above 32 degrees F and water is on the needle. |
| Sphaeropsis Tip Blight |
Shoot tips are attacked in the spring and a canker
forms at the base of the new
shoot. Resin oozes from the canker. This often occurs on
scattered branches low on the tree at first. Close examination
of the dead and dying tips reveals that the tissue was killed
before the needles reached full size. Lower branches are
killed in succeeding
years. Old cones and dead needles persist on the tree and
have small dark
brown to black, pimple-like fruiting structures peppering
their surface. |
Sphaeropsis sapinae
(formerly Diplodia pinae) |
Do not plant young, healthy two- and three-needled
pines near older, infected pines. Remove infected twigs to reduce
the amount of fungus in the tree. Irrigate trees to prevent
drought stress. Do not use high nitrogen fertilizers on pines.
Apply azoxystrobin, thiophanate methyl or copper beginning as
the buds swell in the spring and repeat application until the
needles reach full size. Spraying at other times is not effective. |
| Ploioderma Needlecast |
March-May the year following infection, red-brown
spots develop on needles. Tips of needles girdled by spots die
while needle bases remain green and needle remains attached
to twig. Black fungal fruiting structures that look like lines
in the dead area of the needle form. Needles are cast in May-June
the year after infection. |
Ploioderma lethale (formerly
Hypoderma) |
Space plants and control weeds to insure good
air circulation around the tree. Apply chlorothalonil or mancozeb
three times at three-week intervals beginning in late May. |
| Lophodermium Needlecast |
March-May the year following infection, needles
on lower branches turn completely brown and fall. Black fungal
fruiting structures that look like lines form on the cast needles. |
Lophodermium |
Space plants and control weeds to insure good
air circulation around the tree. Apply azoxystrobin, chlorothalonil,
triadimefon + chlorothalonil, or mancozeb three times beginning
in mid-July and at three-week intervals. However, if early summer
is warm, begin in mid-June. |
| Needle Rust |
Two and three-needled pines develop small, cream-colored,
baglike pustules on the needles. These rupture and release orange
spores that blow to and infect goldenrod and asters where the
fungus overwinters. Pines are infected the following summer
by spores from aster and goldenrod. |
Coleosporium asterum |
Little damage occurs and no control measures
are recommended. If disease severe in a nursery situation, apply
myclobutanil in the late summer to protect the needles. |
| Pine-Pine Gall Rust |
Many round
galls form on the branches and enlarge up to several inches
in diameter. Approximately 15 months after infection, masses
of yellow spores erupt from the galls and infect new pine shoots. |
Endocronartium harknessii |
Inspect plants very carefully and prune all galls.
Inspect all newly purchased seedlings carefully for galls. Destroy
infected seedlings. |
| Pine-Oak Gall Rust |
A few galls, which may swell to 10 inches in
diameter, form on two- and three-needled pines. Masses of yellow-orange
spores erupt from the galls about a year after infection and
blow to red oaks. Small areas of yellow-orange spores develop
on the underside of oak leaves in the summer. These spores reinfect
oak. Small, brown, hair-like fungal structures, where the fungus
overwinters, develop on the underside of oak leaves late in
the growing season. |
Cronartium quercuum |
Inspect plants very carefully and prune all galls.
Do not establish a two- and three-needle pine nursery close
to or within a red oak stand. Inspect all newly purchased seedlings
carefully for galls. Destroy infected seedlings. |
| Root Rot |
Trees, particularly white pines, are stunted
before any other symptoms appear. Infected trees decline, yellow,
wilt, and die. Dead needles remain attached. Resin oozes from
a girdling canker at the soil line or several inches above the
soil. Wood beneath the bark where resin is oozing is chocolate
brown to black. |
Verticicladiella procera |
Trees most susceptible are ones growing on poor
sites for pines. Remove infected trees and do not replace them
with pine. |
| White Pine Blister Rust |
White pines develop swollen cankers on the trunk
or branches. Resin flows from the cankers. Powdery yellow to
cream-colored spores erupt from the cankers in May through July
two to three seasons after infection. Branches and entire trees
are girdled and die. Spores formed on the pine infect the leaves
of currants and gooseberries (Ribes).
Spores formed on currants and gooseberries infect pines through
the needle. The fungus then grows into twigs, branches, and
the main trunk. |
Cronartium ribicola |
Destroy currants and gooseberries in and around
nurseries. Purchase and plant only rust-free plants. Inspect
pines frequently and prune out any infected branches cutting
12 inches below the canker. |
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