No. 5/June 15, 2020

Modified Growing Degree Days (Base 50⁰ F, March 1 through June 14)
Insect development is temperature dependent. We can use degree days to help predict insect emergence and activity. Home, Yard, and Garden readers can use the links below with the degree day accumulations above to determine what insect pests could be active in their area.

Viburnum Leaf Beetles
The viburnum leaf beetle, a native to Europe, was brought to North America on infected viburnums. While it is established in several northeastern states, we've only confirmed this pest in a handful of counties in northeast Illinois. If your viburnum plants are showing signs of defoliation, please keep your eyes open for larvae now or Viburnum Leaf Beetle adults during the summer.

Sickly Spruce
In the last issue of this newsletter, Diane Plewa noted that the U of I Plant Clinic has received numerous evergreen samples infected with needle blight and needle cast diseases. Each spring, the U of I Plant Clinic receives calls, emails, and samples regarding sick/dying spruce trees. The following are the most commonly diagnosed spruce diseases by the plant clinic:

Is it Spray Drift and What Do I Do?
On average, each year the Illinois Department of Agriculture (IDOA) receives approximately 120 pesticide misuse complaints, of which 60% are pesticide drift complaints. Many of you know that the number of complaints has been much higher in recent years due to the allowed use of dicamba on soybeans and the apparent extreme sensitivity of surrounding plants to small amounts of dicamba. Detailed label restrictions were quickly put into place to reduce the incidence of drift with those products. Regardless, drift complaints have been around for as long as pesticides have and certainly, dicamba is not the only one to blame. It’s June and we are in the midst of the growing season for gardens, landscapes, and field crops. At this point, thousands of acres have been sprayed with herbicides and the emails concerning possible herbicide injury to non-target plants have started to come in.

A Homeowners Guide to Troubleshooting a Misapplication of Pesticides
A pesticide misapplication can happen to even the best of us. In a recent email, a homeowner shared the following.