I have many Blue Spruce trees on my property and believe many are infected...

Asked November 10, 2017, 4:30 PM EST

I have many Blue Spruce trees on my property and believe many are infected with needle cast disease. Can I send something in to have it verified and second what fungicide should I use and when and how should it be applied?

Medina County Ohio pine trees blue spruce

3 Responses

Hello,

You can send branch samples to the OSU Plant and Pest Diagnostic Clinic in Columbus to have your plant tested for possible diseases or other issues. Find more information here: https://ppdc.osu.edu

If you wish to go this route, here are some tips for selecting samples and mailing.

  • There is a 20$ fee that will be invoiced to you.
  • You should send samples overnight shipping to ensure they arrive fresh.
  • You must fill out this form, print and include it in the box https://ppdc.osu.edu/sites/ppdc/files/imce/General%20Form%2003-31-2010.pdf.
  • Use the address at the top of this sheet for shipping.
  • Include as much detail as possible and also enclose a photo of the trees to help the pathologists make the best diagnosis.
  • Do not mail completely dead branches. You must select branches in the "transition zone" that are declining but not dead. We recommend finding a sickly branch and trace it back to the tree until you find heathy tissue (or trace inside out if the problem is beginning interiorly). Prune behind the healthy tissue. Bacterial and Fungal diseases of plants are active in these transition areas.
The clinic will test your sample for pathogens and return a report to you with the identification, if the sample is good, and any treatment options. We cannot recommend a fungicide or other treatment without confirmation of what the problem is as there are multiple possible causes of evergreen decline, including poor site selection, root issues, natural needle drop, mites, as well as fungus and bacteria.

Here is a nice factsheet on spruce problems as well for your information: https://web.extension.illinois.edu/plantclinic/downloads/Plant%20Clinic%20Report%20Spruce.pdf

If you have other questions, feel free to contact your county extension office at 330-725-4911

What is a good time of year to do this? Is spring better? What is the optimal time?

The clinic manager said that if the tree is currently dropping needles, you can sample the affected branches now that are showing discoloration. However, do not gather needles or fallen branches off the ground.