Spruce Tree Dead on Top

[BrentDH]

Any idea what might have happened to this Colorado Spruce tree?  The top 6-8' just died off.  I guess I don't really need to know what happened unless there is a danger of whatever it was spreading to the adjacent trees.  So maybe my real question is what should I do about it now?  I am inclined to send one of my younger, smaller family members up there and have them trim it off at the dead to live transition.  My hope would be that, with nothing blocking its way, a new sprout might take ownership of the leader position and somewhat recover.  What say the braintrust - trim it off or leave it alone?

It is only the very top that died.  There are no signs of problem lower on the tree.   In the second picture it looks like there are some dead spots part way up on the right, but those are just branches from an Ash tree behind it that has lost its leaves.  (The ashes will be dying soon too, but that is a whole different ash borer problem unrelated to what happened to the spruce.)

   

   

[JosephP]

Betcha a nickel there is white sap running down the trunk.

Probably pitch mass borer - bugs chewing (boring) underneath the bark causing the tree to produce big globs (masses) of sap (pitch).

These are secondary pests... where are you located (edit: nevermind, didn't see the location when I was posting on mobile...I see now MN)?  Rhizosphaera needlecast has been hammering Blue spruce throughout the midwest.  This stresses them making them susceptible to secondary pests.

The bug is feeding on the vascular system of the tree. A systemic insecticide will get to them IF there is enough vascular system left to transport it up there.  Dinotefuran (Safari) or Emamectin benzoate (Tree-age) are what we use.  Imidacloprid does a decent job, but doesn't move as quickly and doesn't work against lepidoptera (some of these borers are moths).

[JosephP]

PS:  those 3 products also do great against emerald ash borer.  We use imidacloprid and tree-age the most for those.

Safari is the most expensive product....but easy to apply (as a bark spray).  Tree-age is injected into the tree, so probably the most costly to have done.  Imidacloprid would be the easiest/cheapest for DIY, as  you can just do a soil drench around the base of the tree.

[Bob10]

Hope you have a spot to drop it.  I have never seen one that had that happen and survive

[JosephP]

Hope you have a spot to drop it.  I have never seen one that had that happen and survive

We've seen them recover OK.  Rarely do they ever look good again, so I should have qualified that in my comments above.  It is possible that a branch will curve upright and be a new leader, but it is just as likely it will stay flat on the top.

My first question to a client when I see that would be "how bad would you miss this tree?" before offering treatment options.

[bmich]

Any idea what might have happened to this Colorado Spruce tree?  The top 6-8' just died off.  I guess I don't really need to know what happened unless there is a danger of whatever it was spreading to the adjacent trees.  So maybe my real question is what should I do about it now?  I am inclined to send one of my younger, smaller family members up there and have them trim it off at the dead to live transition.  My hope would be that, with nothing blocking its way, a new sprout might take ownership of the leader position and somewhat recover.  What say the braintrust - trim it off or leave it alone?

It is only the very top that died.  There are no signs of problem lower on the tree.   In the second picture it looks like there are some dead spots part way up on the right, but those are just branches from an Ash tree behind it that has lost its leaves.  (The ashes will be dying soon too, but that is a whole different ash borer problem unrelated to what happened to the spruce.)

I would guess they are bagworms,  also a pain to get rid of.

[JosephP]

It could be, but that doesn't really look like bagworm damage.

As long as you can reach them with a sprayer, bagworms are really easy to control. It is all about timing... Treat them in late June/early July after they have hatched. They're very susceptible to just about any insecticide. We use Conserve SC for those early treatments. When people don't notice them until later in the year, we switch to a bifenthrin based product.

If you treat bagworms now, you will accomplish absolutely nothing.

[BrentDH]

JosephP, thanks for your advice.  It is always appreciated.  You have been very helpful with a few past questions as well.

So it sounds like my options are
1)  Buy Safari and spray it directly on the bark for a quick attempt to halt further damage.
2)  Buy something like this (1.47% Imidacloprid) and dump it diluted in a 5 gallon bucket of water around the tree and wait for the roots to absorb it and send it up the trunk.
Amazon.com: BioAdvanced 701615A Gal Tree and Shrub Control, 1 gallon, Concentrate : Patio, Lawn & Garden
3)  Or both.

With the Safari, do I attempt to coat the entire trunk from top to bottom?

We are approaching freezing time so I assume in either case I should do it SOON.

I assume the adjacent trees are at risk as well and the Imidacloprid fed in through the roots of those would be a good idea as well to protect them from future infestation?

In either case I think it would be good to trim that top off to clear the way for any new growth that MIGHT fill it in, correct?

[JosephP]

I would do the imidacloprid now There isn't much difference in efficacy between spring and fall treatments see might as well get it going.

I will probably wait until next May to do the Safari treatment. It does not last as long in the tree, so I want to make sure it is at full strength when the Tree is more capable of spreading it throughout. You do not spray the entire trunk. Just from about 4 ft high down to the ground

Imidacloprid is so cheap, I would be tempted to treat them all.

If you can reasonably get up there to get the top out, yes, I would trim it back down to live branches...