Sample numbers submitted to the plant diagnostic clinic drop off significantly this time of year. We have continued to get a few samples from a variety of plants.

A major portion of the samples we receive continues to be from trees and shrubs. We have received a number of samples from oaks. One additional pin oak was positive for oak wilt. Suspect bacterial leaf scorch samples were sent off for ELISA serological testing, but were negative. Other oak samples had iron chlorosis and Tubakia leaf spot. We have continued to see the effects of the summer drought on juniper and arborvitae, especially in poor soils and exposed locations receiving little irrigation. An additional juniper sample had a serious spider mite infestation. We have received a number of calls and samples from arborvitae and white pine displaying normal fall needle shed symptoms. We also continue to receive samples from callery pears displaying fireblight symptoms, although we have not been able to isolate the bacteria responsible from these fall submissions, because it is many months after the damage occurred.

We have not received many fruit and vegetable samples in recent weeks. A pear sample was submitted with typical stink bug or plant bug feeding injury. Tomato samples with leaf miner infestation, whitefly infestation and Rhizoctonia stem rot were submitted.

Ornamental and turf submissions included zoysia with large patch and hydrangea with Cercospora leaf spot.

We have had a few recent arachnid/insect submissions including the woodlouse spider, wolf spider, citronella ant and lone star tick.

We welcome your submissions, and look forward to working with you to identify your samples and provide management suggestions. Please refer to the sample submission section of our website or contact us for more information on sample submission.

Simeon Wright
Plant Diagnostic Clinic
573-882-3019