Troubleshooting corn emergence problems early is critical in identifying solutions and developing successful replant plans, if needed. Here's a list of a few common things to look for if you encounter an emergence problem in corn this spring, according to Dr. Peter Thomison, OSU Agronomist.
- No seed present. May be due to planter malfunction or bird or rodent damage. The latter often will leave some evidence such as digging or seed or plant parts on the ground.
- Coleoptile (shoot) unfurled, leafing-out underground. Could be due to premature exposure to light in cloddy soil, planting too deep, compaction or soil crusting, extended exposure to acetanilide herbicides under cool wet conditions, combinations of several of these factors, or may be due to extended cool wet conditions alone.
- Seed with poorly developed radicle (root) or coleoptile. Coleoptile tip brown or yellow. Could be seed rots or seed with low vigor. Dark, discolored roots and crowns, instead of a healthy creamish-white appearance, are typical symptoms of seedling diseases problems.
- Seed has swelled but not sprouted. Often poor seed-to-soil contact or shallow planting: seed swelled then dried out. Check seed furrow closure in no-till. Seed may also not be viable.
- Skips associated with discolored and malformed seedlings. May be herbicide damage. Note depth of planting and herbicides applied compared with injury symptoms such as twisted roots, club roots, or purple plants.
- Seeds hollowed out. Seed corn maggot or wireworm. Look for evidence of the pest to confirm.
- Uneven emergence. May be due to soil moisture and temperature variability within the seed zone. Poor seed to soil contact caused by cloddy soils. Soil crusting. Shallow planting.
Note patterns of poor emergence. At times they are associated with a particular row, spray width, hybrid, field or residue that may provide some additional clues to the cause.
Often two or more stress factors interact to reduce emergence where the crop would have emerged well with just one present. Also, note the population and the variability of the seed spacing.
This information will be valuable in the future.