Weekly Scouting Report - August 12, 2014
I scouted corn fields near Hoopeston this week that were planted the end of April. The corn was in the late dough stage, not too far from denting. More corn leaf aphids are showing up, but they shouldn’t be a problem in corn with adequate moisture after pollination.
I have received a few calls about whether corn is firing from lack of nitrogen or is it just going through its normal maturity stages. Some questions I ask are: when was the nitrogen applied, how much rain have you received, what soil type and what stage is the corn in? These are all reasons a plant may start firing prematurely. I believe the future will hold better ways of monitoring N loss and applying before a problem may arise.
In a year with normal rainfall, leaf death should occur when the corn plant reaches black layer or physiological maturity. Bottom leaves should begin to die first and then progress towards the upper portion of the corn plant as maturity is reached. N deficiency is a typical, naturally occurring event late in the season. Corn with a dense canopy blocks the sunlight from the lower leaves and they cannot photosynthesize.
The plant shuts these leaves down and uses the nutrients they would use elsewhere. If firing happens too early though, and reaches above the ear leaf, tip back could occur. Also stalk quality could become an issue because of cannibalization.