Blue Spruce browning at top

mikemerkJuly 1, 2007


I have about a seven year old Blue Spruce in my yard. It is in full sun. The needles on the tree are a beautiful blue color. Today however, I just noticed that the top leader is turning light green to brown. When I looked at it, the needles appear to be dying from the trunk outward. I noticed that on the top bark of the tree there are little black spots (black spots are not on the needles.) I sprayed it today for spider mites but I was wondering if anyone has any ideas in case it is not mites such as a desease. I am enclosing a picture of the tree but you will not be able to see the black spots but you can see the browning of the top. Any ideas?



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I've been looking at this since this morning. I can't conclude anything.

Maybe and this is as long of a 'long shot' as I've ever quite possibly taken, but, it 'could' be symptoms from the terrible winter and/or spring fluctuations and... well, I just don't know to be exact.

Sure looks weird (you can always train a new leader next year, no matter what).


    Bookmark   July 2, 2007 at 8:03PM
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Does white pine weevil ever hit Blue Spruce? If yes, that would be my guess.


    Bookmark   July 2, 2007 at 8:46PM
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Insect! Buy product.

12 Big Spain I'm nice to meet you.

    Bookmark   July 3, 2007 at 12:42AM
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They will go after CBS in Oregon...actually only seem to go after Piceas here, no pines. I have only seen them infest the new growth, when at about 3/4 expansion, it collapses like a wet noodle(the vascular system totally gobbled up).
Just by the photo, I would think something else. The problem seems to start at last years terminal buds and radiate out, going into new and old growth.
It would still be worth checking for grubs just under the bark.

    Bookmark   July 3, 2007 at 8:11AM
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I'm parachuting out of this one.


    Bookmark   July 3, 2007 at 1:52PM
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mehearty(So ME z5a)

That looks exactly like something that's been happening to our young white pines. The leader starts to get lighter, then brown & dead looking with some curly looking old branches off to the side of the leader. Eventually the tree recovers & a new leader takes over. I watched this with a few white pine last year (wish I had taken pics) and some hemlock as well. I have no idea if the mature trees ever had it since I can't really see up there. =) Come to think of it, I have not seen that phenomenon this year which has been a very dry year. Last 2 years were very wet.

I generally photograph *everything* in my garden but since these weren't specimen trees, I pretty much ignored it. If I find any pics w/the brown topped trees in the background, I'll post them.

    Bookmark   July 3, 2007 at 9:58PM
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This is a long shot, but maybe it's a sirex wasp doing this damage. I just read about this pest invading the states in NYC. Not sure if it's going to affect spruces, they only mentioned pines, but your damage sounds the same as the damage the sirex wasp causes. Can't hurt to check it out.

    Bookmark   July 4, 2007 at 10:15PM
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You need to go up and cut this dying part out and then slice through the lower part and see if there are any grubs inside or evidence that grubs have already eaten out the center and then exited. I go with pineresin--it looks exactly like white pine weevil from the outside.

We had a discussion here a few months back about whether white pine weevil attacks blue spruce. I said I have never seen it where I am in VA nor at my mountain timberland in western MD. One or two others assured me that in at least some parts of the country white pine weevil does, indeed, attack blue spruce.

But it is easy to find out--cut the dying part out and do some slicing and see what you find. I am sorry I have been so late getting to this post, but I just had shoulder surgery. Any time you see what looks like white pine weevil damage you need to cut out the affected part ASAP and destroy the grubs. The earlier the better, because as the grubs grow they continue to eat their way downward, destroying more of last year's leader.


    Bookmark   July 7, 2007 at 9:08AM
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Well guys, I originally sprayed it for spider mites with Kelthane and then the other day with Sevin. It didn't seem to be getting any worst but then I read spuceman's post. Anyone who has a username of spruceman and for that matter conifers and pineresin should know a lot about this situation. Spruceman convinced me to cut it off. Well here is what was inside. I had to take quite a bit off but, I think I got it all. Should I do anything with the exposed top where it was cut? i.e. apply pruning tar...etc

Thanks again guys.


p.s. I live in Jackson, NJ so I guess you can say White Pine Weevil does attack Blue Spruce here.

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    Bookmark   July 9, 2007 at 7:14PM
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No need to treat the cut surface with anything. It is too small to get any kind of fungal infection, and it will probably seal itself with pitch.

If you make a lengthwise slice through the stem you can see what was going on inside better, and maybe see more clearly if any grubs are left inside.

You may get another attack soon, although often the same tree is not attacked in consecutive years because the little buggers like nice fat shoots.

Control methods? I guess you have already done a web search for that. I have so many spruce trees and have had so many other things to do, I have never used any except for a few young trees to cut off the infected shoot and destroy the larvae. I read somewhere that these bugs do not fly well and often crawl up the tree trunks, making some kind of barrier a possibility. If I knew when these bugs will emerge from the ground the next spring I have imagined some kind of temporary but impenetrable barrier cloth under last year's infected tree(s) might frustrate them, but this is just my own invention and I have not tried it.

Your tree will probably develop its own new leader without any problems, but if after two or three years a double leader persists, you can cut off one.


    Bookmark   July 9, 2007 at 7:36PM
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??? Did you find/see any white grubs located between the bark and the woody portion of the terminal?? The reason I ask is WPW typically feed on cambium tissue, the don't bore into the center of the shoot (but shot-hole borers/Ambrosia Beetles do) least it looks like borer damage in the center of the cross sections.

    Bookmark   July 9, 2007 at 8:40PM
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After I read the second post by spruceman, I sliced the leader lengthwise and there were whitish-yellowish grubs in the dead center of the shoot. Actually, although it didn't come out too good in the photo, the piece of the shoot on the far left has a grub in it. Look close at the picture.


    Bookmark   July 9, 2007 at 8:59PM
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Thanks Mike. I would say you have a case of a shot-hole borer/Ambrosia Beetle(yes, they do go after Piceas). Treat as mentioned above for WPW, but these buggers can have several flights a year on the left coast, not sure for your area...check with a local state extension service. Keep your tree ?healthy?...chemical means/needs vary from year to year, for a home enviroment it is not always realistic to use.

    Bookmark   July 9, 2007 at 9:46PM
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Well, in spite of the opinion of schmoo, I still think it is most probably white pine weevil. But I admit I am not that familiar with shot-hole borers and am not an expert on identifying the grubs. My primary reason for thinking white pine weevil is the site of the attack--the leader shoot only--last year's growth--and the pattern and timing of death at the top, with this year's shoots dying after they have grown for a few weeks as their supply of sap and nutrients is cut off. I have done a search on shot-hole borers and can find no reference to a special and restricted site of attack like this nor the timing and pattern of damage/death. I have seen this kind of attack/pattern literally hundreds or really thousands of times on my 20 acres of spruce trees over the years.

Of course if after you do your own research on these two kinds of pests you have any doubt, you can take the grubs, and/or the damaged shoot, to someone to identify.

It is important to find out so you will know what to expect in the future and how you might want to deal with this. For me with so many spruce trees and such constant attacks, I have generally done little or nothing, as I said before. Spruce trees, unlike white pines, are not often affected so severely as white pines because of their internodal shoots/buds providing good oppotunities for the trees to establish new leaders without serious distortions to the stem and ultimately the form of the tree. In a small percent of cases an attack will result in multiple leaders. With my Norway spruce, this happens in only about 5% of the trees even after multiple attacks over a span of many years. The worst effect is perhaps some modest growth loss over the life of the trees.

But if you have one or a few trees and another attack is likely, I would be careful to cut off any future affected areas and destroy the grubs. I also suggested the barrier kind of solutions previously. And if you want to spray and can find out the timing of the females emergence and possible attack on the leader, this might be the most effective remedy. Most of my trees are so tall I can't contemplate anything like that.


    Bookmark   July 10, 2007 at 11:14AM
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I agree with the location of the problem being a very good indicator of WPW. In Orygun for instance, shot-hole borers are more of an issue with shade & ornamental trees..boring into trucks and branches. I have never seen them on conifers here.
BUT...I have also never seen WPW grubs boring into the center of a new shoot...they have always been feeding on the cambium/vascular system. Mike indicated the grubs were in the center of the shoot, not the outside.
I know these pests don't read our books and I am always open to going "wow, have not seen that before" opinion here is based solely on the feeding habit's of the insect's involved...most/all? shothole borers/Ambrosia Beetles do not feed underneath the bark, they are in the "wood".


    Bookmark   July 10, 2007 at 6:49PM
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Here is a cross-section of the leader.


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    Bookmark   July 10, 2007 at 8:01PM
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Mike and schmoo:

This cross section is very interesting and certainly raises doubts in my mind about this being white pine weevil. Schmoo--I compliment you on your observation of the detail in the original cross section picture posted by Mike.

OK, now my interest is really high in this case. Mike--do you think you could take your samples, both the shoot and the grubs, if you still have them, to some kind of university extension, or forest service, or something for a positive ID?

One thing I have seen with some spruces from time to time, both Norway and blue, is a fairly large portion of the top of the tree dying, sometimes four to as much as ten feet or more. These trees quickly re-establish a leader and grow back the top quickly, so it is not a problem with general decline. I have always suspected a borer or some kind, but have never had the opportunity to make any observations/diagnosis. Anyway, what killed the small portion of the top of Mike's tree may be what has killed the larger portions of the tops of some other spruces I have seen. I have always wonderered.

Anyway, Mike, I would be very appreciative if you could follow up with some appropriate source of info and get an answer for us.


    Bookmark   July 11, 2007 at 9:13AM
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I will see what I can do. I know I don't have any of the grubs but I should still have the cross-section in the picture. I say "should" because my wife (Mrs. Clean) already said to me yesterday, "What are you saving that for?" I told her to just leave it alone but, it wouldn't be the first time she ignored me and threw something out. On top of that, today was garbage day.

I will be away starting tomorrow through the weekend on business but, when I return I will look into visiting the Rutgers Cooperative Research & Extension.


Here is a link that might be useful: Rutgers

    Bookmark   July 11, 2007 at 11:23AM
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I have a blue spruce that is about 40 years old and maybe 30 feet tall. Last year it started to die from the top down and now is maybe 1/3 to 1/2 dead looking.I cannot easily get to the effected area. The damage I see is, needles turn brown and fall off. My tree man said he thought it was from the drought in our area. I would like to know if there is a chance I can save it if I do find borers or sawflies? Most of the people I have talked to seem to think it is too late.
Thanks in advance for your thoughts. Appreciate your time. Kelman....

    Bookmark   February 26, 2008 at 2:31PM
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My problem was definitely the result of borers. If you do not remove not only the affected area but a small portion of the healthy area too, I'm afraid it will die....assuming it is insect related. Borers live inside the bark and insecticides do not affect them. Your problem sounds extreme. I keep a very close eye on my trees and shrubs and try to react fast if I see a problem. I caught the problem on my blue spruce and only had to remove about 5% of the tree.

If 1/2 of the tree is dead, would you really do any further damage if you just cut it off. Are you sure it is not something else like bagworm?

I feel your pain. Blue spruce trees are beautiful but it can take a long time to get a 30 foot tree.


p.s. Some of the other guys here give really good info so maybe they can help as I am only a novice.

    Bookmark   February 26, 2008 at 7:31PM
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Hi Mike, thanks for the note. I have been looking with a scope for bagworms and there are none. Over the years I have had bagworms but they normally cut the needles off, These turn brown and fall off. After reading the info on this subject I must conclude it is borer infestation or sawflies. If I cut out the dead part the tree will look awful. It is half the tree from the top down. Even if I rid the tree of its problem I don't know if the needles would come back to the damaged area. I feel that they would not. But I have seen white pine grow back needles. Plan to prune one of the effected limbs and check for whatever but I will need an extension pole.Just thought someone might know if the needles will re establish themself if I can fix the problem. Tree man wants to cut it down. I can always do that but want to make sure it has every chance. K.....

    Bookmark   February 26, 2008 at 8:17PM
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I'm almost positive that the needles will NOT return to the dead area. If you cut off a portion of the infected area and there is no sap and it is dried out, there is no hope.


    Bookmark   February 27, 2008 at 1:02PM
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I know you are probably right Mike. I will have to get up in the branches and cut one off. When the weather improves I will do so. Hope to find out what I have and share it here on the board. Guess I was hoping for a simple fix. Just found this site and it has been most helpful. thanks again

    Bookmark   February 27, 2008 at 9:53PM
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Greetings, same issue with browning top of blue spruce.

Zone=5 Stevensville, MT
2 Blue Spruces planted last year mid June.
Faired well until just about the time the grasshoppers appeared, pre-heat.

We soak water the trees every other week, no fertilizer used on the trees. Water from a well-raw untreated.

Primary tree has the most damage. Note the grasshoppers congregating only at the top. Note the sap ooze.

Second tree is across the gravel driveway about 17 feet from primary damaged tree. See pic's. They are high res pictures so if you need to enlarge to zoom in you 'should' be able to

What causes this? Where (if) do I cut the damage off, and do I check for grubs with a perpendicular cut to damaged area?

How do I properly cut (again if) the damaged area off?

What other treatments, etc. are needed if any?

Many thanks for this site and any help.

Here is a link that might be useful: Slideshow of tree damage

    Bookmark   August 2, 2009 at 12:15PM
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I have a new Baby Blue, planted in the spring, which has browned out at the top - new leader and new side branches. I had thought that it was a "chopper" where the roots were inadequate for the new plant. But perhaps this thing came "infected" with White Pine Weevil (when do they migrate from tree to tree in Zone 6?) in which case it could infect my other trees if I dont yank it out and destroy?

    Bookmark   August 17, 2009 at 1:31PM
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My 6 year old trees have been doing great until now. The tops
are starting to curl up and some branches on the ends are
turning pink and the needles are falling off. They are Fat Boys Blue Spruce. Is it too much water or mites or something
else. Please advise and thanks.

    Bookmark   August 19, 2011 at 12:36PM
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