R6 Stage: Physiological Maturity*
(Begins 55 - 65 days after silking.)
By the R6 stage, kernels have attained their maximum dry weight or dry matter accumulation. The hard starch layer has advanced completely to the cob. A black or brown abscission layer forms, moving progressively from the tip ear kernels to the basal kernels of the ear. It's a good indication of physiological maturity and signals the end of kernel growth. The husks and many leaves are no longer green, although the stalk may be.
Tips*
GDUs Required** to reach R1 growth stage depends on maturity and is approximately:
CRM | GDUs |
---|---|
80 | 1,895 |
90 | 2,145 |
100 | 2,390 |
110 | 2,640 |
120 | 2,890 |
Scout for these Common Pests and Diseases | Timing* |
---|---|
Anthracnose Stalk Rot | R5 through R6. |
Diplodia Ear Rot | R5 through R6. |
Diplodia Stalk Rot | R5 through R6. |
Fusarium Ear Rot | R5 through R6. |
Fusarium Stalk Rot | R5 through R6. |
Gibberella Ear Rot | R5 through R6. |
Gibberella Stalk Rot | R5 through R6. |
Stewart's Wilt | Disease is initiated with corn flea beetle feeding from VE to V5. Leaf symptoms appear after R1. |
Click on the insect or disease for more information.
* Information from Pioneer and Iowa State University Extension.
Use this information as a guide and it should not be the only factor in making decisions.