Plant and Insect Diagnostic Clinic Update - October 3, 2017

News Article

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 for updates and more pictures. For more information on a particular disease or insect problem listed, follow the article (hyperlink) cited.

Plant Diseases and insect damage

The following highlights represent recent sample submissions from fruit, vegetables, and ornamental plants.  

Symptoms and signs of Powdery mildew in Viburnum
Symptoms and signs of Powdery mildew in Viburnum. top: notice the mycelia and small black fruiting bodies, bottom: magnification of fruiting bodies (chasmothecia)

Broadleaf Trees

Oak - bur oak blight

Maple, Tar spot, Physiological scorch, physical injury (crack)

Oak, Iron deficiency, Twolined chestnut borer, Kermes scales

Willow, willow leaf spot

Coniferous Trees

Spruce - Stigmina needle cast, rhizosphaera needle cast, sudden needle drop, spruce spider mites, Spruce budscale

Pine, bark beetle damage

Ornamentals Perennials and Annuals

Rose - rose rosette disease

Viburnum - powdery mildew

Hawthorn - woolly apple aphid, cedar hawthorn rust

Ornamental pear, Botryophaeria canker 


Raspberry - rednecked cane borer, crown gall


Pumpkin, Bacterial Leaf and Fruit Spot, Powdery mildew, Aphids


Symptoms and signs of Powdery mildew in Viburnum
Rednecked cane borer.  Top: typical swelling of the raspberry cane.  Bottom: tunneling and frass underneath the bark.





Lina Rodriguez Salamanca Extension Plant Pathologist and Diagnostician (Program Specialist II)

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 North Central Plant Diagnostic Network (NCPDN) and National Plant Diagnostic Net...