P&PDL Picture of the Week for
March 1, 2004

Corn Oddities: Silk Balling

Bob Nielsen, Extension Corn Production Specialist, Purdue University

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.


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Purdue Plant & Pest Diagnostic Lab Purdue Cooperative Extension Service