Plant and Insect Diagnostic Clinic Update

July 23, 2014

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.


It has been an interesting couple of weeks in the clinic. We have seen impatiens downy mildew, botrytis blight on peony, and raspberry cane borer.

Impatiens Downy Mildew


Impatiens downy mildew is caused by a pathogen that is similar to fungi. This disease has caused a lot of problems for growers in the past few years. Symptoms usually begin with leaves turning yellow and then they will begin to fall off until only a bare stem is left on the plant.  (Photo 1 & 3)  The white downy fungus can often be seen on the undersides of the leaves. (Photo 2) There is no effective treatment once plants are infected.

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