Diseases of Spruce trees

To the left is a Spruce tree infected with Rhizosphaera.

This fungus usually preceeds Cytospora Canker by weakening the tree and making it an easy target for the deadly Canker.

Needles become infected one year and the next year they turn a purplish-brown.

First spray should be applied when new needles are half grown and again when fully grown.

Rhizosphaera is easily controlled in 2 seasons unless the tree has become heavily infected.


Above is Sirococcus Shoot Blight.

You will see new needles die and fall off and other shoots will curl and become hooked shaped. This fungus can kill seedlings but generally won't cause severe damage to older trees.

This 30 year old spruce tree started showing signs of Cytospora Canker this year.

There are areas of dead branches throughout the tree.

We used to think that a big part of the fungal problem was caused by trees and rows too close together.
This causes less air movement and when the trees started touching each other the fungus spread more quickly.
Some of this is true but I can find single specimens with no other similar conifer near-by and they are becoming infected at an alarming rate this year.

This is a picture of the same tree above but one year later (June of 2000).
As you can see the top 4 feet of the tree has now died.

This 10 year old spruce showed signs of Rhizosphaera & Cytospora a few years ago.

As you can see 50 % of the branches are infected or dead now.

Once the spruce tree gets Canker it will probably die.

These spruce trees are around 50 years old.

Once they were infected with Cytospora Canker it took less than 5 years to kill 80% of the tree branches.

There is presently no labeled fungicide for control of this disease.

If you decide to remove infected branches or dying trees don't take them to a recycling center!

After removing fungus infected branches and/or dying trees burn them if at all possible and ASAP.
I realize there may be burning restrictions but if these branches are taken to a wood chip/recycling center and then someone takes wood chips & needles from these infected branches you will only help to spread these diseases.

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