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Type of Sample Needed for Diagnosis and Confirmation
The first and most important step for managing a tree disease is accurately diagnosing the problem. The best approach to diagnosing tree problems is to start by submitting photos of the tree.
General pictures of the tree (location, whole plant appearance) and specific ones (twig, leaves and trunk close-ups, canker or cracks, in limbs and the base of the plant, etc.) would be appreciated. See our guidelines on taking and sharing photos on our page: https://hortnews.extension.iastate.edu/pidc/digital-photograph.
If you suspect winter damage, starting with photos is the best alternative, as it is impractical to collect a physical sample, as there are no tests we can conduct in the clinic that confirm that is the case.
Concerned about conifer diseases?
See the interactive conifer disease key to help you determine what your problem might be and what type of sample is necessary for diagnostics.
The Iowa State University Plant & Insect Diagnostic Clinic can help you investigate and confirm if your plant has this disease. Please see our website for current forms, fees, and instructions on collecting and packing samples. Contact information for each state's diagnostic laboratory for U.S. residents can be located on the NPDN website. If you have a sample from outside of Iowa, please DO NOT submit it to the Plant & Insect Diagnostic Clinic without contacting us.
Dr. Lina Rodriguez-Salamanca is a diagnostician and extension plant pathologist with the Iowa State University Plant and Insect Diagnostic Clinic (clinic.ipm.iastate.edu), a member of the National Plant Diagnostic Network (NPDN, ...
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