Some corn fields where corn has emerged, the coleoptile and first leaf appear pale yellow to gray or transparent.  The weather over the last few weeks has been cool, slowing crop development.  Pale or transparent corn leaves are often a result of cool, wet conditions.  Plant metabolism slows, resulting in an inability to absorb nutrients (nitrogen).  Plants will quickly grow out of this phase once warm weather arrives. 

Silver leaf syndrome is described as parts of individual leaves appear gray (as if freezer burnt).  This is often associated with rapid cooling of leaf tissue at night (single-digit night temperatures), which causes chilling injury to plant tissue.  Damaged tissue is often horizontal to the ground. The affected tissue will not die immediately, as with frost injury.  New leaves will emerge normally (Bob Nielson – Purdue).

The effect on yield in both cases is often negligible.   

Seedlings with signs of cool weather do have a weakened tolerance to some herbicides.  Post-emerge herbicide applications should be delayed until seedlings show “normal” development. 

Shawn Winter, CCA-ON, Maizex Seeds Product Development Manager
Twitter: @SWinter_Maiz