spruce canker or borer?

V

venuti

I have old Colorado blue spruces in NJ. I have exudates on my trunks and on some branches. All trunk exudates are located above 8 feet from the ground. All exudates have dripped and dried to a blue-white powder. But some exudates form an almost waxy clump. (Sorry, I have no photos).

My trees have been inspected by two different certified arborists. One claims that it is cytospora canker, and the other claims that it is pitch mass borer and wants to tree it as such. Is there a way to differentiate cytospora canker from pitch mass borer by visual inspection? Thanks in advance.
 
The canker(fungus)chokes and kills branches where the borer will bore into the bark and sap wood.
One is a fungus the other is an insect.
Look for holes in and around the wounds that would indicate boring.

I'm not an arborist but I play one on the Buzz.

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Has the infection started in the lower branches and moved upward?

Cankers will form at the ends of small branches and progress down the limb. The cankers will girdle the branch and cause dieback of the branch from the point of infection out. The resins you will get from the cankers is a bluish white.

If it is a borer my guess would be that you would see sawdust or frass in the resin that is exuding from the tree. With the pitch mass borer you could also dig around in the pitch to find the borer. Pitch mass borer also tends to lay it's eggs near wounds or pruning cuts on the tree.
 
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