Comment by 'Farmers Edge':

"Plants should die from the top down, as they translocate resources to the fruit or seed."

-- I don't think this is correct.  The leaves at the bottom of the plant are the oldest, and the tendency of the plant is to allow the senescence of those leaves first and to protect the younger ones.  Nutrient deficiencies, drought, and other stresses accelerate this, but the pattern is the same even if the plant is quite healthy with abundant nutrition.  I can't think of any annual or perennial species that are an exception to this (egad, must be another ag universal !).