There is no general agreement on weather conditions that are most favorable for common smut although most reports indicate that common smut is prevalent following rainy, humid weather. There also are reports linking increased infection rates with wounding of plants, as may occur during detasseling. Galls on leaves and stalks of seedlings often are observed following strong thunderstorms with heavy winds, especially when plants are injured by blowing soil. Obviously, germination and dissemination of teliospores and/or sporidia would be favored by wind and rain. However, anything that induces rapid localized cell division and elongation, such as wounding, could increase susceptibility to smut infection. Factors that reduce the production of pollen or inhibit pollination also increase the occurrence of ear galls of common smut because ovaries are protected from infection by U. maydis soon after they are fertilized, mostly likely because silks attached to fertilized ovaries die and are thus no longer susceptible to infection. For example, hot, dry, drought-like conditions often cause asynchronous pollen production and silk emergence which results in poor pollination. Ear galls of common smut may be prevalent if U. maydis is readily disseminated to stigmas of unfertilized ovaries during or immediately following these hot, dry conditions. Thus, some people associate the occurrence of ear galls with droughts although the droughts probably affect the prevalence of ear galls primarily by increasing the number of unpollinated ovaries with rapidly growing silks.