Droopy Ears of Corn Due to Drought
RL (Bob) Nielsen, Extension Corn Specialist, Department of Agronomy, Purdue University
Ears of corn normally remain erect until some time after physiological maturity has occurred (black layer development), after which the ear shanks eventually collapse and the ears decline or "droop" down. In recent weeks, corn field connoisseurs have reported droopy ears in drought-stressed fields that have not yet reached physiological maturity.
Droopy ears are cute on certain breeds of dogs, but droopy ears on corn plants prior to physiological maturity are a signal that grain fill has slowed or halted. Premature ear declination (the fancy term for this problem) results in premature black layer formation, lightweight grain, and ultimately lower grain yield per acre.
The most common contributing factor seems to be severe drought stress that extends late into the grain filling period. The "droopy" symptom suggests a loss of turgidity in the ear shank with stress, possibly combined with some cannibalization of the ear shank similar to what can occur with the stored reserves of the main stalk. Eventually, the ear shank collapses and the ear droops down.
For more information, see my article at http://www.kingcorn.org/news/timeless/Droopy.html