# Target cankers on Sugar Maple



## tree MDS (Mar 16, 2008)

This has been bothering me: years ago I was trimming what should have been a beutiful big sugar maple, but all the branches were loaded with target cankers. I did some research but could'nt find any difinative answers, I was thinking nectria canker? Is there any thing you can do for this that would actually help?


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## D Mc (Mar 16, 2008)

Out here we have seen these large target cankers (_Nectria galligena)_in old Silver maples (_Acer saccharinum_). Even the old well-developed cankers don't appear to cause the tree too much trouble and haven't appeared to girdle the limbs. We will be interested if there is a treatment of this fungus as we haven't heard of any. 

They enter through lesions and wounds, the most prominent causes (that we have seen) have been oriented to crossover limbs. So one might presume that anything that would reduce bark lesions would also reduce the spread of the canker. We also understand this is more of an issue back east than here in the west. 

D and S Mc


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## tree MDS (Mar 16, 2008)

D Mc, yeah, that looks like it, this poor tree was loaded, pretty much all limbs. I think I read somewhere that you're supposed to prune infected branches-obviously not possible here unless maybe a basal prune. Now this was a long time ago, but I suppose I should have disinfected my pruning tools before I pruned the other maples nearby right?


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## Urban Forester (Mar 16, 2008)

According to the USFS: "Cankering may be minimized in high value areas by avoiding wounds and pruning out branch cankers. Sterilize pruning tools before moving to an uninfected tree and conduct pruning operations during dry periods when spores are less abundant."


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## tree MDS (Jun 2, 2009)

So I did a search and found I already asked about this... hmm.

The client called me back yesterday to look at some more treework, and of course we get to this tree again and its looking really rough now. Poor tree, I actually feel bad for it, now its showing major dieback to the cankers, there is alot of dead tips all over.

It would be a major job to trim all those dead tips, even with the bucket there would still be alot of climbing as the tree is pretty good sized. Here is my question(s): the customer asked me if we should cut it down to avoid the disease spreading to the other Maples (they are all in a row along the street), is this the way to go? Or, should I just charge her to deadwood it as best I can going with the theory of gimping it along so at least she can enjoy the tree for a while longer? I think it would be close to the same price to just remove it.. I dont want to waste her money if its just going to die slowly anyways. Pruning all the cankers out would leave no tree.

I'm supposed to do some research and call her back this morning. I'm just curious what some of you more experienced arborists would do in this scenario?? 

BTW, I've never seen so many cankers on a Sugar Maple before - and we have alot of em here. The trees are subject to drought and as I mentioned located roughly 15' from the street, there was alot of dead tips in the other trees last time I pruned them as well, but they seem to be doing pretty good just at a quick look. My thoughts were that the combination of drought and salt damage (it is a long straight away and very smooth road, I know the plow trucks must fly past those trees at like 50 splashing salt all over thier root systems) may have predisposed the tree?? Sorry no pictures, but I will take some and someday figure out how to post them. 

Thanks, MDS.


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## D Mc (Jun 2, 2009)

First of all, here is what we do for posting pictures:

Open the picture in Paint, select Image, then select "Stretch/Skew". We then opt for 25% on horizontal and vertical reduction. Save. 

This reduces the picture to a size the forum will accept and yet be big enough for people to view.

When you do take your pictures. Include closeups of the canker itself. Perennial cankers generally do not kill the tree, as they co-exist with the tree. They develop during the tree's dormant period, then the tree overcomes the fungus during its actively growing time. This interplay goes back and forth; obligate parasitism.

So if the tree is dying, it would probably be from multiple issues, which you have alluded to. Your suspicion on the salt is a viable thought. However, this would probably express itself more on one side than the other.

Other stressors could be weed and feed products. Many species are sensitive to the typically available chemicals used: 2-4D, Mecoprop, triclopyr, and Dicamba; which can have an accumulative affect over the years.

Don't overlook vascular wilts in your search of this tree's decline. 

These are the questions that need to be answered in making your decision of removing the tree or only deadwood.

Dave


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## tree MDS (Jun 2, 2009)

Thanks D Mc.

The problem I'm having is that to prune the deadwood out I would have to prune back to the cankers or just remove the cankered limbs entirely sinse the tips are dying back to them and there is nothing sufficient to cut to below the cankers. And pretty much all of the limbs have cankers on them.

Its a shame because even with all the cankers it was a beautiful (other than tips dying back) and very healthy tree- just infested with these things.

I'll try to work on the picture thing. I really dislike posting this without pics, but I need to figure this out soon as I'm in need of the work...maybe I'll just give her a price for the other work and take some pics from the bucket while I'm there. If I do have to take this tree down i want to know why at least.

Any thoughts as to the disease spreading to the neighboring trees?? Is this thing just a festering disease pool and a liability for them? or is that not an issue? They seen ok so far.

And yes, the dieback is much worse on the side facing the street. My problem is why just this tree as the others are not nearly as big and nice as this tree was when I first entered it, about six years ago - other than the cankers.


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## tree MDS (Jun 2, 2009)

Also, if this helps: on the smaller branches on the bottom that I could reach, the cankers (if that is what they are) appear semi-round and in the open center you can see what I assume is the original branch before infestation, now deadwood, the tips are dead beyond that.


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## D Mc (Jun 2, 2009)

From what you describe, this tree sounds like it is at the end of its run. If this is a perennial canker and the other trees don't have it, probably for whatever reason they are resisting it, I don't think there is much worry of this tree being a festering disease pool. 

However, that still doesn't save this tree. 

Also that canker you described is different than your typical target canker that I was visualizing. Pictures would work well here.

Dave


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