One of several potential causes of pollination failure
in corn is a phenomenon traditionally called "silk balling".
I prefer the name "scrambled silks" because I think it is
more descriptive. The problem is one in which silk elongation, prior
to their emergence from the husk leaves, is interrupted or altered,
resulting in a mass of scrambled silks near the tip of the cob that
never fully emerge from the husk.
Obviously, any silks that fail to emerge from the husk will not be exposed to
any pollen and consequently will fail to contribute to the formation of kernels
on the cob. The net result is some degree of barrenness on the cob and, consequently,
lower yield. Typically, the severity of the resulting poor kernel set is low
and concentrated near the tip end of the cob. However, I've seen situations in
the past where scrambled silks resulted in severe barrenness in nearly 1/3 of
the plants in a field.
Scrambled silks is a relatively infrequent problem and its causes are not well
understood. Some believe that the occurrence of cool nights (low 60's or cooler)
prior to silk emergence plays a role in the development of scrambled silks. Others
believe that rapid changes in temperature patterns (e.g., very warm to very cool)
prior to silk emergence encourages the problem. Hybrids with naturally tighter
husks seem to be more susceptible to developing scrambled silks.
Whatever the cause, the good news is that this phenomenon
occurs only sporadically over the years and can be lumped into that
broad category of corny oddities.
--Bob Nielsen, Extension Corn Production Specialist, Purdue University |
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