Plant and Insect Diagnostic Clinic Update - October 3, 2016

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.


Broadleaf Trees

We continue to observe fungal leaf spots on several tree species. The most common in being Pseudocercopora leaf spot in lilac, Poplar leaf spot, and Tubakia leaf spot.


Bur oak blight is also one of our more frequent samples in the last month.  See the Clinic website for more information.  

Fruit (small and tree fruit)

Bitter rot has become a problem in grapes clusters. This disease is managed by a combination of sanitation practices and fungicide sprays. For a fungicide, spray program for commercial production of grape visit the Midwest Fruit Pest Management Guide 2016.


Apple scab, sooty mold and flyspeck continue to be seen in apple fruit at the time of harvest.

Mushroom Identification

We are happy to assist in identification of fungi. see  Mushroom Identification page. 


We often receive digital images where we cannot see key characteristics, making it impossible to identify a mushroom with certainty. In fact, to identify mushrooms, we need a physical sample accompanied by digital pictures. Please see our video on how to collect and submit a mushroom sample for identification at and our article on the steps to collect mushroom for identification.


Remember the ISU Plant and Insect Diagnostic Clinic Identifies Mushrooms, Not Edibility. We do not make recommendations about whether you should eat them.


Lina Rodriguez Salamanca Extension Plant Pathologist and Diagnostician

Dr. Lina Rodriguez-Salamanca is an extension plant pathologist and diagnostician with the Iowa State University Plant and Insect Diagnostic Clinic  (, a member of the National Plant Diagnostic Network (NPDN,&nbsp...

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