Plant and Insect Diagnostic Clinic Update – September 15, 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 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.  

Tubakia leaf spot
Tubakia leaf spot in red oak. Top: foliar spots. Bottom and middle : signs of the pathogenat different ,agnifications

Broadleaf Trees

Amur Maple, suspected decline, fungal canker

Bur Oak, bur oak blight, oak tatters, oak bullet galls

Red oak, tubakia leaf spot, wind damaged petioles  

Pin oak, oak vein pocket gal

Oak, lace bug damage

Crabapple, cedar apple rustsapsucker damage, phoma leaf spot, scab  

Maple, decline, anthracnose, physiological scorch, iron deficiency, tar spot, aphids

Birch, Septoria leaf spot 

Coniferous Trees

Black Hills Spruce, drought stress suspected

Hemlock, rust mites

Pine, Diplodia tip blight

Spruce, Rhizosphaera needle cast, Stigmina needle cast, suspected fungal cankerspider mite damage

Perennials and Annuals

Boxwood, Volutella canker, and leaf blight 

Serviceberry, lace bugs, rust 

Ninebark, spider mite damage


Lawn, Curvularia leaf spot, leaf spot and melting out, anthracnose, rust 


Cucumber anthracnose

Cantaloupe, Alternaria leaf blight

Tomato, leaf mold, suspected magnesium deficiency

Fruit (small and tree fruit, including hops)

Cherry,  gummosis

Apple, Cedar-apple Rust

Grape, grape downy mildew, suspected black rot

Blackberry, anthracnose

Hops, Apple Mosaic Virus

Household and Landscape

Yellowjacket wasps are active and causing concern as "bees" of autumn.  

Plant ID


Snow-on-the-mountain, a poisonous plant to cattle




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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