| DISEASE |
|
SYMPTOMS |
MANAGEMENT |
| Brown
spot, Mycosphaerella dearnessi |
Fungi
|
Most
pine, esp. Scots and ponderosa. Spots
that enlarge to bands and encircle
the needle develop in late July and
August. Diseased needles often have
dead tips. Killed needles drop late
in the fall. |
Nurseries
should use seedlings from resistant
trees; allow for adequate spacing and
avoid shearing and other operations
when foliage is wet.
CHEMICAL: Mancozeb. |
Dothistroma
needle blight
(also called red band), Mycosphaerella
pini |
Fungi
|
Two-and
three-needled pines are affected but
most common on Austrian pine. Chlorotic
spots appear on infected needles in
fall and winter. Spots spread, turn
red/brown and girdle needles causing
the distal end to die. Black fruiting
bodies break through lesion surface
in spring. Defoliation can be severe. |
Remove
the lowest whorl of branches on young
trees. Clean out debris and weeds in
and around trees. Space plants for
good air circulation. Avoid planting
in low-lying areas with poor drainage.
Growers should shear trees during dry
weather.
CHEMICAL: Bordeaux (8-8-100). Can be
toxic to new needles. |
| Needlecast,
Lophodermium seditiosum |
Fungi
|
Two-and
three-needled pines, esp. Austrian
red and Scots pine. Current season
foliage develops yellow spots which
turn brown with yellow margins in late
fall and spring. Black, elliptical
fruit bodies mature in or just beneath
the epidermis in late summer. Needles
brown and drop. Twigs die back. Spores
are released during late summer/early
fall rains with most infection occurring
in August and September. |
Improve
air circulation with thinning and pruning:
cool moist environments favor infection.
CHEMICAL: Nurseries should apply mancozeb
plus a spreader sticker or chlorothalonil.
Make 3-4 applications starting July
1. |
| Pine
needle rust, Coleosporium sp. |
Fungi
|
Two-and
three-needle pines develop light-colored
blisters which burst open to release
yellow/orange spores in early summer.
These spores infect the alternate hosts
aster and goldenrod and NOT pine. |
Damage
is seldom detrimental. Remove or mow
goldenrod and aster plants in the immediate
vicinity.
CHEMICAL: None recommended. |
| Pine-oak
gall rust or eastern gall rust, Cronartium
quercuum |
Fungi
|
Two-and
three-needled pines are susceptible.
The alternate host is red oak. Globose
swellings up to 10 inches in diameter
form on pine branches. Yellow/orange
powdery-appearing spores form on the
gall surface in early summer. |
Remove
galls on pine branches preferably before
spring.
CHEMICAL: None recommended. However,
if the situation warrants, mancozeb
may be applied when yellow pustules
form on pine galls. |
| Pine-pine
gall rust or western gall rust, Endocronartium
(Peridermium) harknessii |
Fungi
|
Two-needled
pines, especially mugho, ponderosa,
red and Austrian pine. There is no
alternate host. Rough, globose galls
appear on branches and trunk. Yellow/
orange powdery spores form on the gall
surface in early summer. |
Remove
galls on infected trees. Remove all
trees with galls for a distance of
300 yards around nurseries and cull
infected seedlings.
CHEMICAL: Mancozeb when yellow spores
are present on galls. |
| Shoot
(Diplodia) blight, Sphaeropsis sapinea |
Fungi
|
New
shoots are invaded and killed in the
spring, usually before needle expansion
is complete. Needles turn brown; resin
soaking is common. Dieback may progress
into main stem. Fruiting bodies form
at the base of infected needles, on
twigs and on second year cones. Austrian
pine is extremely susceptible after
reaching cone-bearing age. |
Keep
landscape trees well watered and stress
free. Thin forest stands. Avoid shearing
during wet weather or high humidity.
Plant less susceptible pine species.
CHEMICAL: Benomyl, thiophanate-methyl.
Begin when new growth starts. Use a
spreader sticker. Also Bordeaux. |
| White
pine blister rust, Cronartium ribicola |
Fungi
|
Five-needled
pines are susceptible (eg. eastern
white pine, limber pine). Elongate
cankers with abundant pitch flow develop
on trunks and branches causing branch
dieback or ãflagging.ä White blisters
containing yellow/orange spores break
through the cankered areas in the spring.
Spores produced on pine infect the
alternate host, Ribes species. |
Minimize
use of white pine on sites with high
blister, rust hazard ratings. Avoid
planting currants and gooseberries
in the vicinity of white pine. Remove
the lower branches on large trees.
Scout trees annually for ãflaggingä
suggestive of early infection and remove
infected branches.
CHEMICAL: Triadimefon. |
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