These images depict kernel abortion on ears of corn from a visibly drought-stressed field that I walked on August 1. The plant symptoms included death of lower leaves plus severe rolling and the typical grayish cast to the green color of the remaining live leaves. The kernel development stage of the surviving ("normal") kernels was R4 (dough), suggesting that pollination had occurred in the early part of July.
The whitish, shriveled appearance of the affected kernels is typical of aborted kernels. Note that the yellowish embryo is visible in some of the larger aborted kernels. Evidence of kernel development is difficult to identify near the tips of the ears, suggesting that those ovules were never pollinated or that kernel abortion occurred very shortly after pollination had occurred.
The minimum estimated yield loss in this one field due to kernel abortion would range from 25 to 50 percent, equal to the percentage of kernel abortion on the ears. Ultimate yield loss could easily be greater if the drought stress continues and limits the final kernel weight of the surviving kernels.