Firs, pines, Douglas fir: on branches of the upper crown the youngest needles turn red (brown) in early spring, the lower parts of the crown remaining green. Douglas fir: in addition to the needle discoloration oval bark necroses on twigs and branches caused by the microfungus Potebniamyces coniferarum, mostly close to the nodia; the parts distal from the necroses die. Commonly Douglas fir needle casts are present as well.
Affected tree species
Douglas fir; Fir; Spruce;
Needle; Stem; Shoot/Twig/Branch;
During the past years damage to Douglas firs were a common phenomenon following winters, when warm periods had activated the photosynthetic activity of the trees, which, as a consequence of the still frozen soil caused water deficiency of the upper crown parts and the drying out of branches. Bark necroses by the Potebniamyces coniferarum and attacks of bark beetles are of secondary nature.
Curative measures No curative measures possible; dead trees or dead parts of trees should be removed to avoid secondary damaging agents.
Sooty needle cast of Douglas fir
Bark beetle attacks on Douglas firs weakened by frost drought
Phomopsis-disease of Douglas fir (Potebniamyces coniferarum), commonly following frost damage