During the past week, several questions have been raised about tassel ears in Ohio corn. Corn is the only major field crop characterized by separate male and female flowering structures, the tassel and ear, respectively. However, in most corn fields it is not unusual to find a few scattered plants with a combination tassel and ear in the same structure - a "tassel ear." The ear portion of this tassel ear structure usually contains only a limited number of kernels.
Tassel ears often appear on tillers (suckers) arising from plants with normal ears and tassels. These tassel ears are produced at a terminal position on the tiller where a tassel would normally appear. However, tassel ears may also be produced by individual plants. No specific cause of this condition is known but it often occurs in shorter spindly plants associated with delayed emergence and uneven crop development. Some hybrids may also be more prone to tiller under certain environmental conditions and these tillers may give rise to tassel ears. Tassel ears are frequently observed along the edges of fields where early season soil compaction and saturated soil conditions may have contributed to this abnormal growth and development. This year tassel ears may be particularly evident in fields where green snap damage occurred at the V11-14 stage. When stalks broke or snapped off near the base of plants, tillers have usually appeared and some of these are producing tassel ears.
Tassel ears are a reminder that the male and female parts of the corn plan are structurally very closely related. Wild progenitors of corn-teosinte spp. have complete flowers tassels and silks together. These can be crossed with Zea mays (normal corn).
There has been some speculation that a fungal disease called "crazy top" may be responsible for this abnormal ear condition. Crazy top does affect the appearance of tassels and ears but the symptoms are distinctly different from those of the tassel ear phenomenon. Crazy top causes the tassel and/or the ear to become leaf-like. In severe cases, the whole top of a plant and ears are replaced with a mass of leaf-like structures. Visual symptoms and more details concerning crazy top are available online at http://ohioline.osu.edu/ac-fact/pdf/0034.pdf.