Plant and Insect Diagnostic Clinic Update – August 11, 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 cited.

Plant Diseases and Insect Damage

Cucumber anthracnose symptoms (top) and signs (bottom)
Cucumber anthracnose symptoms (top) and signs (bottom). Photo credit: Lina Rodriguez Salamanca, Iowa State University Plant & Insect Diagnostic Clinic.

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

Broadleaf Trees

Pin Oak, Oak Wilt

Bur oak, Bur Oak Blight

Pin Oak, Horned oak gall  

Catalpa, Suspected abiotic scorch

River Birch, suspected nutritional deficiency and decline. see Nutrient/Soil pH Imbalances

Maple, Wood boring insect damage

Magnolia, Verticillium Wilt

Walnut, walnut caterpillars

Coniferous Trees

Eastern White Pine, Phomopsis tip blight, see article from University of Illinois Extension

Spruce, Rhizosphaera Needle Cast

Spruce, Black Hills Spruce, Pine, suspected abiotic disorder

Spruce, Spruce spider mite

Black Hills Spruce, Spruce, Stigmina needle cast

Perennials and Annuals

Marigold, blossom rot, botrytis blight. see Gray mold

Hosta, Fusarium crown and rot rot, bacterial soft rot

Walnut caterpillars.
Walnut caterpillars.  Picture by Anne Winslow-Cook.


Lawn, Nigrospora blight  

Lawn, Curvularia leaf blight  

Lawn, establishment issues


Cucumber, anthracnose, see University of Minnesota article on cucurbit anthracnose

Tomato, Suspected Juglone toxicity, see University of Wisconsin article on Black Walnut Toxicity

Fruit (small and tree fruit, including hops)

Ornamental Pear, Fire Blight

Pear, Pear leaf blister mite

Apple, Apple Maggot damage  

Strawberry, Pythium root rot, Fusarium crown rot  

Household and Other Insect Pests

Strawberry root weevil

Lone star ticks

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