No. 14/August 22, 2016
Testing for Bacterial Leaf Scorch
Bacterial Leaf Scorch (BLS) is a serious infectious disease with a wide host range of trees and shrubs. The disease causes the slow decline of the host, resulting in host death. It is caused by the bacterium Xylella fastidiosa which is also responsible for Pierce's Disease in grapes and is currently causing widespread damage to the Italian olive industry.
Bur Oak Blight and Look-alike Diseases
The U of I Plant Clinic has received many samples and questions regarding diseased bur oak trees. Most clients were concerned about possible Bur Oak Blight or Oak Wilt infections. This article will address some of the key diagnostic symptoms for Bur Oak Blight and some of its look-alikes.
Fall Webworm
Fall webworm is numerous in the state, particularly southern Illinois. It lives as a group of caterpillars that spin a communal silk web. This silk nest typically encloses the end of the branch and associated leaves. The caterpillars remain in the webbing, feeding on these enclosed leaves. When the leaves inside the web are eaten, the silk webbing is expanded to include more leaves. Webs of mature caterpillars are typically 2 to 3 feet long.
Zimmerman Pine Moth
Zimmerman pine moth is a common trunk and scaffold branch borer in Scotch, Austrian, and red pine in Illinois. It is a shoot tip borer in Eastern white pine. Although it is difficult to control once inside the tree, its life cycle makes it relatively easy to control while on the outside of the tree.