Host resistance is the most efficient way to control common smut (Ustilago maydis) in sweet corn, but resistance to U. maydis is not understood well. All meristematic tissues are susceptible, but infection is localized. Ear galls result from infection of ovaries. Infection and resistance can be affected by plant morphology. For example, ovaries are protected from U. maydis infection when an abscission zone forms at the base of the silk 6–24 h after a pollen tube reaches an ovary. The objective of this study was to determine if the rate of silk abscission differed between two related sweet corn hybrids that differed in susceptibility to smut infection of ears. The two hybrids, Green Giant Code 3 (GG3) and Green Giant Code 46 (GG46), were evaluated for the occurrence of infected ears in 58 paired plots at four locations near Le Sueur, MN, from 1993 to 1999. The rate of silk abscission in the two hybrids was evaluated in two field trials in Urbana, IL, in 2002 and 2004. Incidence and severity of ear smut were significantly (P < 0.05) greater and about twice as much on GG3 than on GG46. Silk abscission was more rapid on GG46 than on GG3. Although this association does not prove that decreased susceptibility of GG46 to ear infection is due to silk abscission, it is a logical basis from which to hypothesize that silk dynamics and other aspects of maize floral biology play important roles in resistance to ear infection by minimizing the time period that all ovaries on an ear are exposed to infection by U. maydis. This hypothesis is discussed in relation to the results of this and other research.