Gordon Johnson, Extension Vegetable & Fruit Specialist; gcjohn@udel.edu
Several sweet corn varieties in our fresh market bicolor variety trial are showing leaf scald symptoms in 2012. We saw similar leaf scald last year in processing varieties. Leaf scald is a physiological disorder similar to necrotic sunburn in fruits and vegetables. It occurs when leaf temperatures rise above a critical level, cells die rapidly, leaving a bleached white appearance. While newly emerged leaves in the upper canopy of susceptible varieties that are the most exposed are the most likely to scald, some of the leaf scald we are seeing this year has progressed deeper into the canopy, even showing up on some of the corn husks. Leaf scald occurs most commonly when temperatures are in the high 90s or over 100, skies are clear (high solar radiation), and humidity is low. While effect on yield is usually minimal, leaf scorch at the ear leaf level can affect kernel fill.
Leaf scald symptoms on fresh market sweet corn in a 2012 trial of bicolor varieties.