| Stage | Description | Indications | |
| 0 | Preemergence | ||
| 1 | Emergence | coleoptile above soil | |
| 2 | Single leaf | open | |
| 3 | Two leaves | fully open | |
| 4 | Early whorl | collar of 4th leaf visible; nodal roots developing; leaf growth | |
| 5 | Mid-whorl | collar of 8th leaf visible; 1st and 2nd leaves may be dead; leaf growth | |
| 6 | Late whorl | collar of 12th leaf visible; 1st to 4th leaves may be dead; leaf growth |
Source: U.S. Department of Agriculture Technical Bulletin 976 and Honway, J.J., 1966 Special Report 48, Iowa State University.
| These pages adapted from North Central Region Extension Publication NCR 327. To order a printed copy, see our ordering information page. | Last updated October 17, 1996 by John VanDyk http://www.ent.iastate.edu/cornborer/howdamage/appendix1a.html |