No. 10/June 25, 2012
Insect and mite galls are numerous on trees throughout Illinois this year, as they are in most years. Oaks have the most galls, by far, with most of their galls being caused by tiny gall wasps in the Family Cynipidae. Galls are also caused by gall midges (flies), phylloxerans and psyllids (sucking bugs), and eriophyid mites.
Insect Galls and Insecticides
Insecticide applications rarely provide adequate control of gall insects and mites. Basic to this is an understanding of how galls form and their internal structure.
Emerald Ash Borer
Emerald ash borer has been found in Champaign, IL along Market Street, just south of Interstate 74. This is the second infestation known in Champaign County with it being found in Rantoul a couple of years ago.
"My Spruce is Dying"--Cytospora Canker
The U of I Plant Clinic has been receiving calls and samples from clients because their spruce trees are declining and dying. Many of samples were suspected or found to be infected with Rhizosphaera needle cast, Stigmina needle blight, environmental problems, and spruce spider mites. One sample we received consisted of spruce branches without needles. We examined the branches, and found no signs of disease.
Have You Ever Wondered How the U of I Plant Clinic Cultures and Isolates for Vascular Pathogens?
When someone suspects that their tree is dying from a vascular pathogen such as Oak wilt, Dutch elm disease, or Verticillium wilt, they can send a sample to the U of I Plant Clinic. We usually suggest that they sample from areas of the trees that are showing early symptoms typical of disease as well as wood that may show streaking or darkening of vascular tissue.
Toothed Spurge--the Un-Impatiens
Have you ever let a young plant grow only to later learn that you shouldn't have? I think many of us have been guilty of this. Let's go one step farther. Have you ever transplanted a mystery plant only to later realize that it was not what you thought it was? Well I have and I probably shouldn't admit that openly to the public, but I'm a firm believer in laughing at yourself and learning from your mistakes.