Issue 4, June 20, 2023

Modified Growing Degree Days

Modified Growing Degree Days (Base 50⁰ F, March 1 through June 19)
Station Location Actual Total Historical Average   (11 year) One- Week Projection
Freeport 888 823 1033
St. Charles 872 794 1019
DeKalb 890 818 1040
Monmouth 1090 975 1252
Peoria 1055 1019 1217
Champaign 1142 1069 1300
Springfield 1139 1192 1299
Perry 1127 1120 1286
Brownstown 1335 1103 1490
Belleville 1248 1279 1411
Rend Lake 1341 1368 1501
Carbondale 1252 1302 1407
Dixon Springs 1286 1330 1434

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.

GDD of Landscape Pests
GDD of Conifer Pests

Degree day accumulations calculated using the Pest Degree-Day Calculator Calculator (a project by the Department of Crop Sciences at the University of Illinois and the Illinois Water Survey).

Author:
Kelly Estes

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