Corkscrewed Corn Seedlings
RL (Bob) Nielsen, Purdue Agronomy Department, Purdue University
Emergence of corn occurs by the elongation of the mesocotyl that elevates the coleoptile (or "spike") to the soil surface. The mesocotyl is that white stem-like plant part located between the kernel and the crown of the coleoptile.
Mesocotyl elongation of early-planted corn occasionally veers from its usual upwardly mobile path and instead corkscrews below ground. The end result of such spiraling sub-surface seedlings is either underground leaf emergence or eventual death of the seedling. The good news is that the extent of the problem is usually limited to a few fields each year and a small number of plants (several thousand or less per acre) within an affected field.
Severe soil crusting prior to emergence or occasionally herbicide injury can be causal factors for corkscrewed corn seedlings. However, this problem has also been attributed to large fluctuations between day and night soil temperatures during the early stages of corn emergence. Research reported from Rhodesia indicated that abnormal mesocotyl and/or coleoptile development occurred most frequently when soil temperatures fluctuated from daytime highs of about 80 degrees F to nighttime lows of about 55 degrees F. The data also suggested that extended periods of cold temperatures stunted and distorted seedling growth.
Reports of corkscrewed seedlings in Indiana are usually few and far between, but occasionally correspond to situations when unusually cool soil temperatures or a dramatic fluctuation in soil temperatures occur in fields prior to seedling emergence.
For more information, see my full article on Corkscrewed Corn Seedlings