Plant and Insect Diagnostic Clinic Update – May 19, 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 to ask questions and for updates and more pictures. For more information on a particular disease or insect problem listed, follow the article cited.


Polyporus squamosus mushrooms are common on tree stumps.  
Photo credit: Lina Rodriguez Salamanca, Plant and Insect Diagnostic Clinic

Diseases

Fungal cankers in ornamental trees are commonly secondary to stress.  See article “Cankers and Diebacks with One Common Suspect: Botryosphaeria”

We have received photos and sample from a client worried about lichens in their trees, mainly on the trunk bark. Lichens are organisms that often grow on the bark of trees and are not harming the tree, for more information see our online article for more information. 

Mushroom of the week: We received multiple inquiries about Polyporus squamosus, commonly known as Dryad's saddle or pheasant's back. This is a common mushroom associated with tree stumps and decaying wood in trees.  For more information see this page at the Mushroom Expert.

 

Insects

Bagworms are a caterpillar pest that tend to be worse on urban trees

Bagworms overwinter tied tightly to their host plants.
Bagworms overwinter tied tightly to their host plants.

and on trees in windbreaks where they feed on many different tree species.  One fascinating thing about bagworms are that the adult females do not fly and her eggs are held inside he body and remain in the bag.  The eggs hatch in the spring and the young caterpillars disperse via ballooning, but many keep feeding on the same tree or shrub their mother was on.  This time of the year you can collect overwintered bags in a container that you keep at outside temperatures.  When you observe caterpillars in the container it is likely the eggs on your plants have hatched as well and it is time to apply a treatment labeled for caterpillar control on ornamental plants.  

Bag cut open to reveal a female bagworm moth.
Bag cut open to reveal a female bagworm moth.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

A dead adult female bagworm moth cut open to reveal her eggs.
A dead adult female bagworm moth cut open to reveal her eggs

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Lina Rodriguez Salamanca Extension Plant Pathologist and Diagnostician

Dr. Lina Rodriguez-Salamanca is a diagnostician and extension plant pathologist with the Iowa State University Plant and Insect Diagnostic Clinic  (clinic.ipm.iastate.edu), a member of the National Plant Diagnostic Network (NPDN, ...

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, Horticulture and Home Pest News, 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 May 19, 2017. The information contained within may not be the most current and accurate depending on when it is accessed.