Plant and Insect Diagnostic Clinic Update – August 25, 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 linked.

Plant Diseases and Insect Damage

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

Broadleaf Trees

Bur oak, Two lined chestnut borer  

Bur oak, Bur oak blight

Symptoms of Verticilllium wilt in coneflowers
Symptoms of Verticilllium wilt in coneflowers

Various Oaks, anthracnose, Eriophyid mite galls, powdery mildew, oak bullet galls, oak tatters, Botryosphaeria twig blight

Pin oak, vein pocket gall

Maple, transplanting stress, for newly planted trees care keep in mind the recommendation on the publication Community Tree Planting and Care Guide

White Ash, Verticillium wilt 

Coniferous Trees

Pine, Pine wilt, Woodboring insect damage

Scotch Pine, Zimmerman pine moth damage 

Spruce, Rhizosphaera needle cast, Stigmina needle cast, Spruce needle miner, Phyllosticta needle blight

Signs (fungal structures) of Verticilllium wilt in coneflowers
Signs (fungal structures) of Verticillium wilt in culture. On the right, cells starting to form sclerotia -resting structure

Crabapple, Cedar apple rust 

Perennials and Annuals

Coneflower, Verticillium wilt   

Hosta, sunscald 

Dogwood, Dogwood Leaf Spot

Highbush Cranberry, Anthracnose 

Willow, Botryosphaeria canker 


Lawn, Nigrospora blight, establishment issues

Turfgrass, Ascochyta leaf blight 


Bell Pepper, Sunscald, Blossom end rot 

Fruit (small and tree fruit, including hops)

Hops, Alternaria cone disorder 

Ornamental Pear, suspected fungal cankers 

Cherry, suspected decline. see publication Understanding Decline in Trees 

Household and Other Insect Pests

Wood cockroach 

Larder beetles

Plant Identification

Quackgrass, see the article Quackgrass was the big winner in drought

Links to this article are strongly encouraged, and this article may be republished without further permission if published as written and if credit is given to the author, Yard and Garden, and Iowa State University Extension and Outreach. If this article is to be used in any other manner, permission from the author is required. This article was originally published on August 25, 2017. The information contained within may not be the most current and accurate depending on when it is accessed.