When a once healthy, thriving blue spruce (or other evergreen) begins to turn brown and drop it’s needles, the evergreen is letting you know it’s in trouble. Cytospora canker is a damaging disease caused by a fungus which attacks older or weakened blue spruce trees and unless it is dealt with promptly, cytospora canker will kill the evergreen.
Cytospora Canker Symptoms on Blue Spruce
Cytospora canker attacks blue spruce and other evergreen trees in the late fall or early spring. The cytospora canker disease first attacks the lower limbs of a blue spruce and gradually works it’s way upward to the top of the evergreen. The needles of the blue spruce will turn a reddish brown, die, then drop off, leaving behind bare branches on the blue spruce. A careful inspection of the blue spruce infected with cytospora canker will reveal resinous pitch oozing from the affected areas of the tree’s limbs and trunk.
Treatment for Blue Spruce Infected with Cytospora Canker
Swift and severe pruning of the blue spruce is the only way to stop the progression of the cytospora canker fungus. Prune away every diseased limb on the evergreen flush to the tree’s trunk.
Pruning the blue spruce can cause the fungus to spread within the evergreen or to surrounding evergreens, unless done properly. Cytospora fungus is much more active just after a rain and the blue spruce is damp, so wait until the foliage and the trunk are extremely dry before pruning the diseased evergreen.
Have a small bucket of household bleach nearby and dip the cutting end of the pruning shears into the bleach between each cut. This will kill all fungus spores that may be on the pruning shears to prevent spreading the disease.
Remove all the limbs pruned from the blue spruce and seal them in a plastic bag before discarding. Burning the cytospora canker infected limbs will not spread the disease, but burn the diseased limbs as far away from evergreens as possible.
The weakened condition of a blue spruce is what caused the evergreen to become susceptible to the damaging fungus. Discover why the blue spruce was stressed (drought, flooding, etc.) and remedy the problem to prevent re-infestation of cytospora canker fungus.
Cytospora Canker Infects Other Trees
Blue spruce or other evergreens are not the only trees susceptible to cytospora canker. Fruits trees and poplar trees can also be infected with the damaging fungus. Severe pruning to remove the diseased limbs and de-stressing the trees (evergreen, fruit or deciduous) is the treatment.