Leaf blade removal of corn plants may occur at any time during the
 growing season because of any of several calamities - insects, animal
 feeding, wind, sandblasting, or hail.  Leaves may also become
 nonfunctional due to disease infections and either extreme low or high
 temperatures.  Hail injury is the most common causal factor in leaf
 removal.  This paper will review the effect of leaf defoliation at
 various growth stages on plant recovery potential, grain yield, and
 plant maturity.