No. 4/June 1, 2020

Modified Growing Degree Days (Base 50⁰ F, March 1 through May 31)
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.

Periodical Cicadas Emerge in Illinois
A periodical cicada (Magicicada spp.) emergence can be an exciting event to witness! Periodical cicadas are already beginning to emerge throughout Illinois and will continue to emerge until late-June. This year two large broods are emerging four years early and will encompass much of the state so many people may be able to this special event in their own yards. Brood XIII includes three species of 17-year cicadas emerging in northern Illinois and parts of central Illinois and Brood XIX includes four species if 13-year cicadas emerging in southern Illinois and parts of central Illinois, so keep an eye out for an abundance of cicadas.

Scouting for Bagworms
When the Japanese tree lilacs are in bloom, it is time to scout for and control bagworms. Japanese tree lilac is a common urban tree that flowers in early- to mid-June, later than other lilac species. The fragrant blossoms are large, white, and hard to miss. But don’t get swept away by their aroma. Bagworm caterpillars may be hatching on nearby evergreens and preparing to find their next host.

Controlling Weeds in the Driveway
Summer is finally upon us. Perhaps you spent the holiday weekend getting the lawn and landscape beds in tiptop shape. Then you noticed the weeds creeping up in the driveway and sidewalk cracks. What can be done in those areas?

Summary of ornamental, fruit, and vegetable samples
It’s no surprise that our sample numbers are lower than usual this year. While the Plant Clinic remains open, we are currently operating with staff in the lab only as needed for diagnostics. We are often not able to answer or return phone calls in a timely manner. If you need to contact us, we suggest emailing for the fastest response.

Maple Leaf Blister
Outbreaks of maple leaf blister were previously considered to be uncommon, occurring only during springs with extended cool, wet weather. However, those conditions have become more prevalent in recent years. As a result, we see outbreaks of maple leaf blister on a more frequent basis.

Sycamore Anthracnose
Sycamore trees have been slow to leaf out this spring, a repeat to what occurred last year. Most of the sycamore trees in central Illinois have remained bare, making them easy to spot from a distance. Infections from this fungal disease occur almost every spring. However, the severity of the infection is dependent on the weather. Aside from the recent summer-like weather, Spring 2020 has predominantly been cool and wet, favoring sycamore anthracnose.