# Green Spruce Blues



## treeseer (May 8, 2009)

Colleagues,

I am not a spruce expert so I am looking for help. I was deadwooding this tree, which looked fine from below. About 40' up, the trunk looked like the attached. No foliar symptoms. Blister rust? Canker? Any potential treatments? The tree is a relative's so we are open to experimental applications.


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## S Mc (May 8, 2009)

Guy, I'm not sure what is going on there with your spruce. What species is it? You said green spruce, but that is a common name, although not very common, for _Picea pungens_. The needles look like a Norway spruce, _Picea abies_, but as the trunk is invisible due to the resin...I'm not sure. You said you couldn't see any injury, insect activity, foliar symptoms, etc. (Just confirming)

If a Norway, the following link had some interesting and potentially relevant facts on how _Cytospora_ canker exhibits on this species. 

http://ag.udel.edu/extension/horticulture/pdf/pp/pp-09.pdf

Particularly interesting to me is the fact that this disease can start at the top (although much more common to start at the bottom with visible foliar dieback) and the cankers are not always visible (on Norways) with the comment about "bluish-white resin" being significant. Fresh resin from an active infection is an amber color. 

It would be interesting to see from where the resin originates on your tree. 

David's carefully formulated WAG was this may denote a possible stress fracture from a wind event. We have seen that on spruces here. Of course, then this opens an infection court...

Keep us posted on other findings.

Sylvia


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## treeseer (May 9, 2009)

thanks syl

Cannot open link now but first I've heard of it starting high up

Davids theory interesting

Will check it out when I reclimb it in a month

Cytospora has been treated with cambistat and phosphite

Mixed results


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## Urban Forester (May 9, 2009)

Considering it's 40 ft. up, that is consistent w/Pitch Mass Borer, however that much resin flow is not. I would lean towards Sylivia's 'wind' possibilty. Does that resin loss seem to be affecting the branches in the general area?


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## S Mc (May 9, 2009)

I was considering pitch mass borer also, UF. But the pitch masses are really quite prominent with this insect. The bluish-white resin is considered diagnostic on cytospora. But it is curious, that there are no foliar symptoms...

And now we will have to wait a month for Det. Dendro to perform a followup...

Sylvia


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## RUBE (May 10, 2009)

Im going to take a shot with the 'ol sap sucker damage. Hard to tell without more pics from up higher. 
If the tree is weakened enough from birds, bugs or planting site than Cytospora canker can move in. If it has the canker I hope you sterilized your pruning tool between cuts as this is a way to help it spread throughout the tree much faster especially if pruned at the wrong time, weather wise.


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## treeseer (May 10, 2009)

there is root stres sthat is being worked on w mulch and water.

no bird or bug signs at all, or foliar issues.


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## hokiewheeler (May 27, 2009)

That grayish ooze (yeah, I know, not the proper terminology) is what we see here in northern Ohio on canker infested spruces as well. Our remedy is pruning to low stump. What do you know about Cambistat treatment for canker and how is this effective?


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## Urban Forester (May 28, 2009)

hokiewheeler said:


> What do you know about Cambistat treatment for canker and how is this effective?



Disease control by using growth regulators is overrated at best and an utter failure at worst. Not to put down Cambistat, it does have it's uses, however the "disease control aspect" is a no go. We've been using cambistat for about 6 years now and don't even mention the possibilty of reduced disease activity. Cytospora "control" to me has always been about reducing ambient stress levels in the tree. Chemical control has always been like taking a shower w/a raincoat on...


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## hokiewheeler (May 28, 2009)

That's what I was thinking. However, if you want to talk about Cambistat as a growth regulator, I can tell you stories of a particular silver maple that had quarter sized leaves on it. Not to digress from the original topic.


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## D Mc (May 28, 2009)

I think it is interesting to note that Cambistat's AI is Paclobutrazol, which also is a triazole fungicide. Amongst its other claims, there have been reports of higher resistance against fungi and bacteria. Which makes sense. 

So its benefits could be more than just slowing elongation of growth in this instance. 

"Paclobutrazol, PBZ (chemical name (2RS, 3RS)-1-(4-Chlorophenyl)-4,4-dimethyl-2-(1H-1,2,4-triazol-1-yl)pentan-3-ol) is a plant growth retardant and triazole fungicide....Among those are improved resistance to drought stress, darker green leaves, higher resistance against fungi and bacteria, and enhanced development of roots. [3] Cambial growth as well as shoot growth has been shown to be reduced in some tree species.[4]" Wikipedia

Dave


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