No. 15/September 9, 2013

Whiteflies are being found commonly in the landscape, feeding on the leaves of flowers and other herbaceous plants as well as hydrangea, other shrubs, and trees. Generally, late season whiteflies can be ignored, as they are too late to cause serious damage to plant health or even cause obvious aesthetic damage.

Potato Leafhopper
Potato leafhopper damage has become obvious during recent weeks. These leafhoppers attack oak, maple, red mulberry, red bud, cottonwood, birch, apple, dogwood, hawthorn, wafer ash, euonymus, black locust, and cherry.

Late Blight (Phytophthora infestans) found on Tomato in Illinois.
Several weeks ago, Purdue University reported tomato infection by Phytophthora infestans, which causes the disease known as Late Blight. More recently, the U of I Plant Clinic received a tomato sample from Northern Illinois also found to be infected with this pathogen. 

Testing for Bacterial Leaf Scorch (BLS) at the U of I Plant Clinic -- Take 2
The U of I Plant Clinic recently completed their first round of serological tests on tree samples suspected of being infected with Bacterial Leaf Scorch (Xylella fastidiosa). 

Bur Oak Blight
Last summer, the U of I Plant Clinic confirmed its first sample of Bur Oak Blight (BOB). The infected tree was located in Lake County, IL. Dr. Tom Harrington of Iowa State University and his research lab have been keeping track of counties and states with trees confirmed to have BOB. As of January 2013, seven counties in Illinois have had confirmed BOB cases.