Plant Disease Management Handbook

See:

Fir, Douglas and True - Hypocotyl Rot and Root Rot

Sugar Pine seedlings with Fusarium cankers on stems and roots.

OSU Plant Clinic, 2022.

See:

Fir, True (Abies spp.) - Heterobasidion Root Disease

Heterobasidion irregulare basidiocarp fruiting on pine sample.

OSU Plant Clinic, 2020.

See

Fir, Douglas (Pseudotsuga menziesii) - Gray Mold

Greenhouse Plants, Ornamental - Gray Mold

Image related to Pine (Pinus spp.)-Gray Mold

Pinus sylvestris with Botrytis.

Melodie Putnam, 2010.

Cause The fungus Elytroderma deformans is a serious needle cast of ponderosa and Jeffrey pine. Hosts also include Coulter, knobcone, lodgepole, and pinyon pine. Spores disperse in spring or early summer, infecting current-season needles. After infecting, the fungus can become systemic, growing through the needle into twigs where it can survive unfavorable conditions. It is most damaging along creeks and lakeshores or in drainages with moist environmental conditions.

Image related to Pine (Pinus spp.)-Elytroderma Needle Cast

Notice the large broom on this ponderosa pine.

Photo by Everett Hansen.

Note the black fruiting bodies (hysterothecia) which form on all surfaces of the dead needles.

Photo by Everett Hansen, 1982.

By M. Agne

Note the swelling of this lodgepole pine branch and yellow mistletoe from that point.

Photo by Kathy Merrifield, 1989.

Image related to Pine (Pinus spp.)-Dwarf Mistletoe

Male and female plants on Jeffery pine.

Photo by Everett Hansen, 1982.

Lots of infections throughout this tree. Note the swellings with parasitic plants growing from that area.

Photo by Everett Hansen, 1999.

Lodgepole pine with moderate dwarf mistletoe infection. Witches’ brooms are found only in the tree’s lower crown, while the upper crown is full and uninfected.

Michelle Agne, 2013.

Lodgepole pine with severe dwarf mistletoe infection exhibiting symptoms of witches' brooms and top kill.

Michelle Agne, 2013.

Dwarf mistletoe plants on the bole of a whitebark pine.

Michelle Agne, 2013.

Cause Dothistroma septosporum (sexual: Mycosphaerella pini), a fungus reported in Oregon, Idaho and British Columbia. Dothistroma pini is found mostly in the North Central United States but has been reported from Idaho.

Image related to Pine (Pinus spp.)-Dothistroma Needle Blight (Red Band)

Spots gradually spread, turn red-brown, and girdle the needles, killing the distal end while the base stays green.

OSU Plant Clinic Image, 2014.

Spots gradually spread, turn red-brown, and girdle the needles. Affected trees may defoliate during the growing season. Symptoms shown here are on Pinus contorta.

OSU Plant Clinic Image, 2014.

Spots turn red-brown and girdle the needles, killing the distal end while the base stays green. Symptoms shown here are on knobcone x radiate.

Photo by Everett Hansen, 1987.

Ponderosa pine with typical symptoms.

Melodie Putnam, 2006.

See:

Fir, Douglas and True - Damping-off

Spruce (Picea spp.) - Cylindrocarpon Root Rot

Image related to Pine (Pinus spp.)-Damping-off

Fusarium stem canker on these sugar pine seedlings.

OSU Plant Clinic collection, 2012.

Fusarium root rot on these Ponderosa pine seedings.

OSU Plant Clinic Collection, 2016.

Cause A fungus, Cyclaneusma minus (formerly Naemacyclus minor). Hosts include Scots, Austrian, Virginia, lodgepole, mugo, and ponderosa pine. Spores are produced on both attached and fallen needles. Rain and wind disseminate spores any time of year when temperatures are above freezing. Spores infect needles through stomata any time from April through November.

Needles turn yellow with brown bars and may remain attached for several months.

OSU Extension Plant Pathology Collection.

Image related to Pine (Pinus spp.)-Cyclaneusma Needle Cast

Melodie Putnam, 2010.

Cause Phytophthora cinnamomi and Phytophthora tropicalis, fungus-like microorganisms. Other species may be involved as Phytophthora citricola and P. citrophthora have been reported in other regions and occur in the PNW. Poorly drained soil or media or flooding encourages disease development. It survives unfavorable periods in soil or media and infected plant debris.

Note the dead plant in left pot, the wilted plant in the center and the healthy plant on the right.

Photo by Jay W. Pscheidt, 1991.

Rhizoctonia and Pythium were recovered from the fine roots, and Phytophthora from the main root piece.

OSU Plant Clinic, 2021.

See:

Rhododendron - Ramorum Leaf Blight and Shoot Dieback

Image related to Pieris (Andromeda)-Ramorum Leaf Blight and Shoot Dieback

Young shoots and leaves turn dark brown and may dieback.

Photo by Nancy Osterbauer, 2003.

Infected leaves turn dark brown.

Photo by Nancy Osterbauer, 2003.