No. 2/May 7, 2019

Issue 2 Intro
We were delayed in publishing the first issue of this year’s newsletter. This issue follows our original planned publishing schedule. As a reminder, we plan to publish issues every other week throughout the growing season. Look for the next issue to ready on May 20th.

Modified Growing Degree Days (Base 50⁰ F, March 1 through May 2)
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.

Lilac / Ash Borer
Lilac borer (Podosesia syringae; also called ash borer) feed on lilac, ash, privet and other members of the olive family. Adult moths are about 1 inch long, slender, with dark brown bodies and yellow banding. They resemble paper wasps in appearance and behavior. They are active during the day and flex their abdomens as they walk.

Boxwood Blight Look-alikes
With the recent detections of boxwood blight in Illinois, the importance of scouting landscapes and new plants for the disease is greater than ever. Boxwood blight can be a challenging disease to identify outside a plant diagnostic laboratory. Many of the symptoms associated with the disease are similar to other common boxwood disorders. One major difference between boxwood blight and its look-alikes is the potential for defoliation. Boxwood blight causes extensive defoliation, while look-alike disorders tend to have leaves turn tan to brown, but remain attached to the plant. A microscope is needed to confirm the disease diagnosis.  Some of the common boxwood blight look-alikes include winter Injury, Macrophoma leaf spot, Volutella blight,  Phytophthora root rot, Fusarium canker, boxwood leafminer, and potentially boxwood psyllid. Fortunately, these look-alikes cause a relatively minor injury that can be pruned out during a dry period of spring weather.

Phomopsis Galls on Forsythia
Forsythias are known for being easy to grow shrubs that are tolerant of many conditions. While they have relatively few known pest issues, we occasionally come across plants with 1 to 2 inches in diameter, round galls, with unique clusters of bumpy nodules pressed tightly together. They are hard to spot during the summer, but they become evident during the dormant season when no leaves are present. Aside from being unsightly, the galls ultimately girdle and kill branch tissues beyond the gall.

Herbicides – Important Tools in Weed Control
Mechanical and cultural methods are important tactics of weed control.  The best weed control programs are ones that take an integrated approach – integrating various control tactics or using various control methods, rather than relying solely on herbicides for example.

Mowing Safety
As the season begins for mowing be sure to keep these things in mind to ensure a safe completed job.

Illinois Invasive Species Symposium
The Annual Illinois Invasive Species Symposium is back on Thursday, May 23, 2019. This year’s agenda has yet another great lineup of speakers from arcross Illinois presenting a variety of topics about invasives. Doors open at 9 am and our program starts at 9:30 am.