Sick Colorado Blue Spruce
Hi we live in Richland county, ND. We have around 300 Colorado Blue Spruce trees that 3 years ago were very healthy and green. The last 2 years we have noticed there needles have thined down tremendously. We have even lost 25 this spring. What could be going on? See attached photos. Thank you. Brandi Anderson
Richland County North Dakota
I have a couple of additional questions to help narrow down the problem. Is the thinning of needles on all sides of the tree? Is there any green growth at the tips of the branches? Is the damage mostly on the lower branches and not as much further up the tree? If you have a magnifying glass, look through the glass at the infected needles. Do you see tiny black spots arranged in neat rows?
Based on your answers, we might be able to better diagnose the problem. Let me know what you find, so I can give you a better answer.
These are typical diseases of blue spruce.
The thinning is all around the trees. It seems lie it starts at the bottoman branches and moves up the trees. There is only new growth at the tops of the trees. I have taken a couple samples of needles from different trees. I am not seeing any black lines in the needles just yellowing spots.
It could be from some form of Needle cast. I am going to re-assign this question to Joseph Zeleznik from NDSU who has had more experience with spruce trees.
Without seeing the fine details of the needles, as well as the overall site, it's hard to say for sure what's going on. Curt may be correct on this being a needlecast problem, but again, we can't know for sure. I would suggest contacting your county Extension agent, Chandra Langseth, at (701) 642-7793. She should be able to help us move forward in the diagnosis process.
Wish I could give you a clearer answer.