Blue spruce needle cast disease

Asked May 23, 2019, 8:12 PM EDT

To whom it may concern, I'm concerned that my blue spruce in the front yard has "Blue Spruce Needle Cast Disease". Please review the attached pictures and give me you assessment and how to treat it. Thank you for your help in advance! Glenn Fye

Livingston County Michigan

1 Response

Hello Glenn,

Thank you for your excellent pictures. Yes, it appears the tree has one or more of the needlecast diseases that affect spruce. There is nothing that brings back the already dead areas, but fungicide sprays applied at the right time can protect new needles that grow at the ends of branches for certain diseases.

There are several other issues with spruce- cytospora canker and some insect pests. One or more of these could also be present. So it is important that needles are examined under magnification to determine which disease/pest is present.

MSU Plant Diagnostic lab can identify the specific problem if you send them a sample taken from the tree that contains diseased and healthy needles. Include pictures of branches and the whole tree. https://pestid.msu.edu

You may hire a certified arborist who will come on site and diagnose the whole tree and give you a care plan. Find certified arborists by zip-code here- www.treesaregood.org

Large trees can not be sprayed properly or safely by homeowners unless they have access to professional equipment and have been trained in its safe use. You can keep dead branches pruned off, fallen needles raked up, and give water to the roots during droughts. If sprinklers are hitting the branches, redirect them so that needles stay as dry as possible( or water only early in the day so needles dry in the sun as soon as possible).

Here are some references that describe the common diseases, treatments, and should you need it, hardy replacement choices-

https://www.canr.msu.edu/news/whats_going_on_with_blue_spruce

http://www.pestid.msu.edu/wp-content/uploads/2016/04/RhizosphaeraApril2016.pdf

https://hortnews.extension.iastate.edu/stigmina-needle-cast

https://hort.extension.wisc.edu/articles/cytospora-canker/

https://www.canr.msu.edu/uploads/files/Alternatives_to_blue_spruce_BertCregg.pdf

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