Corn Diagnostic Guide - Planting to Emergence

 

 

Appearance 

Symptoms 

Possible Cause(s) 

Skips in rows where plants fail to emerge No seed planted 
  • Planter problem or malfunction
  • Seed delivery system plugged or clogged
  • Faulty or incorrect planter plates
  • Empty planter box
  • Uneven or irregular planting depth
  Kernels normal, not germinated
  • Seed not viable
  • Seedbed too dry
  • Seedbed temperature below 50 degrees F
  • Fertilizer placed too close or in direct contact with seed
  • Anhydrous or aqua ammonia injury
  Kernels swelled, not germinated
  • Seed not viable
  • Soil too wet
  • Seedbed temperature below 50 degrees F
  Rotted seed or seedlings
  • Seed not viable
  • Cool, wet seedbed for prolonged period
  • Fungal seed rots or seedling blights
    • Pythium
    • Diplodia
    • Gibberella
    • Rhizoctonia
  Sprouts twisted or leaves unfurled below soil surface
  • Crusted soil
  • Soil compaction
  • Cloddy soil allowing light to reach seedling too soon
  • Herbicide injury
  • Insecticide injury
    • Excessive amount
    • Misplacement
  • Anhydrous or aqua ammonia injury
  • Deep seed placement
Seed eaten, dug up or sprouts cut off  Kernels hollowed out 
  • Seedcorn maggot 
  • Wireworm 
  • Seedcorn beetles 
  Plants pulled up and kernel eaten 
  • Crows, pheasants, blackbirds 
  Unemerged seedlings and kernels dug up and eaten
  • Mice, ground squirrels, groundhogs, gophers, rats, skunks

Planting to Emergence || Emergence to 8-10 Leaves || 8-10 Leaves to Tasseling || Tasseling to Maturity || Corn Diagnostic Guide

Adapted by James H. Hill, Iowa State University - Hancock County Extension Education Director, from information prepared by Dale M. Studt, retired ISU Extension Crop Production Specialist.

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