Plant and Insect Diagnostic Clinic Update - March 23, 2017

The following are highlights and updates about samples and questions recently received in the Plant and Insect Diagnostic Clinic. Visit the PIDC's Facebook page to ask questions and for updates and more pictures. For more information on a particular disease or insect problem listed, follow the article cited.

Plant Diseases

structures (Stigmina signs) observed under microscope magnification.
 Photo caption:  note fungal bodies (signs) on spruce needles (top). Microscopic
pathogen structures (Stigmina signs) observed under microscope magnification.

One of the biggest challenges in plant diagnostics is obtaining and working with a representative sample. We as diagnosticians want to make sure we get a full scenario of where the plants have been developing and what you see in your plant. Unfortunately, incomplete or insufficient information or sample may lead to an inaccurate diagnosis.

Digital photos that accompany a sample give very important clues. See our tips on taking digital photos at

We also have added pictures to our Plant Problem Sample Submission page to show examples of good and bad samples submitted to the Clinic. Check out our new pictures at

Broadleaf Trees

            Environmental Stress and Bot canker on Oak

Coniferous Trees

            Diplodia Tip Blight in spruce

            Rhizosphaera needle cast on Spruce

            Stigmina needle cast in Spruce 

Perennials and Annuals

            Acidovorax bacterial spot - Petunia     

            Root rots- of Geranium and Coleus


            Environmental disorders in transplants (light, temperatures, watering and nutrients)

            Damping off and root rots

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