Douglas B. Gucker 
IL Extension
dgucker@illinois.edu

Douglas B. Gucker 
IL Extension
dgucker@illinois.edu

DOUGLAS B. GUCKER UPDATES

Region 5 | August 13, 2026 | DeWitt, Macon and Piatt

Doug Gucker
dgucker@illinois.edu

Soybean plant with pods from the ground to the top nearing the end of the Beginning Seed, or R5 stage. A Japanese beetle is visible on a leaflet.
Caption: Soybeans nearing the end of the R5, beginning pod stage.
Female Japanese beetle with 3 male beetles on a soybean leaflet. Leaf feeding is evident.
Caption: A female Japanese beetle is attracting several male japanese beetles to her soybean leaf. Leaf defoliation is still below treatment thresholds.
Corn ear in the R5, Dent stage on August 13. Ear tipback is evident.
Caption: More advanced corn fields are in the R5, dent stage.
SYNOPSIS

The majority of the corn and soybean fields are in good to excellent shape. The exceptions are those fields that have suffered some type of weather issue – flooding, storm, or wind damage.
Soybean fields are mostly at the R5 stage, with some at the R6 (full seed) stage. I am noticing Japanese beetle feeding, but at levels below treatment thresholds. Also beginning to see bean leaf beetles showing up in the fields.
Corn fields are mostly in the R4 or R5 stage, dough to dent, but do see the occasional corn field in the R1, Silk stage. Corn leaves are showing minor leaf diseases currently, mostly a little gray leaf spot.

WHICH OF THE FOLLOWING BEST DESCRIBES CURRENT CONDITIONS IN THIS COUNTY?
Mildly Dry (soil is drier than normal, plant growth may have slowed)
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