Douglas B. Gucker 
IL Extension
dgucker@illinois.edu

Douglas B. Gucker 
IL Extension
dgucker@illinois.edu

DOUGLAS B. GUCKER UPDATES

Region 5 | July 24, 2024 | Macon

Doug Gucker
dgucker@illinois.edu

Caption: More mature fields are reaching R3 stage.
Caption: Corn R3 stage to left and R1 Corn on the right
Caption: R1 Corn is showing elevated corn leaf aphid numbers, but not near the thresholds that insecticde needs to be applied.
SYNOPSIS

In general, the corn and soybean fields look good. Weed escapes are beginning to show in a few soybean fields. Early planted soybean fields are in the R3 stage. Early planted corn fields are R3 stage with late planted fields in R1 (silking) stage. Corn leaf aphids are making a presence in the R1 corn fields, but at this time there is no need to apply control measures. Silking corn fields should be monitored for aphid numbers and whether the crop is suffering moisture stress. Current IL thresholds for aphid control in corn is >50% of the corn plants have more than 100 aphids per plant and the plant is in moisture stress; OR >3% of the corn plants have heavily infested tassels and upper corn leaves plus suffering moisture stress. Remember aphids are controlled by insect predators, diseases and rainfall washing them off.

WHICH OF THE FOLLOWING BEST DESCRIBES CURRENT CONDITIONS IN THIS COUNTY?
Near Normal
IF CONDITIONS ARE ON THE DRY END, WHICH OF THE FOLLOWING US DROUGHT MONITOR CATEGORIES BEST FIT CURRENT CONDITIONS
Near Normal (Dnada)