No. 3/May 14, 2018

Modified Growing Degree Days (Base 50°F, March 1 through May 13)
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 in this article to determine what insect pests could be active in their area.

Emerald Ash Borer Adults Emergence
Emerald ash borer activity should be under way in the southern part of the state and we expect activity to begin in central Illinois soon. Adult emergence generally begins with the accumulation of 450-500 degree-days.

Reports of May Beetle Activity
I've received several reports of the presence of May beetles in several areas of the state. Phil Nixon offered a refresher on these insects in a Home, Yard, and Garden article last May.

Broadleaf Seedlings Recently Seen in Central Illinois
Weeds can be challenging to identify. Tiny seedlings can be even trickier. Often times, letting your mystery seedlings grow a little so that all the parts are easier to see and handle can greatly help your identification efforts. Of course, waiting until your weeds are too tall can result in weeds that are more difficult to control. Therefore, timely identification is essential. 

Dothistroma Needle Blight of Pines
We usually see a large number of pine, spruce and other conifer samples at the Plant Clinic in spring. This year we've already diagnosed a few samples of Austrian pine with Dothistroma needle blight. This is a fairly common fungal needle blight pathogen affecting Austrian, ponderosa, Mugo, red, and Scots pine.

Gymnosporangium Rusts on Eastern Red Cedar
Gymnosporangium rusts have been active in many parts of the state for a few weeks. This past weekend, I observed several eastern red cedar trees in the Chicagoland area loaded with sporulating rust galls. This stage of the disease causes minimal damage to the evergreen host. However, the spores produced on these galls will infect nearby apples, crabapple, and hawthorns where injury is much more noticeable. 

Keeping It Clean
Tool sanitation isn't something we typically think about, but as we go from yard to yard with our equipment, we can pick up some unwanted guests. These guests can be as simple as weed seeds, insects, or as complex as fungal diseases.  Pruning tools can carry or harbor plant diseases like fire blight, Dutch elm disease, and boxwood blight. Since we don't want to spread these diseases, a cleaning routine needs to be a priority.