The 2005 corn crop is right on schedule with 85% reported to have reached silk emergence. At this point in time, it is possible to evaluate the degree of success of pollination and the number of potential kernels that can develop.
Each ovule, or potential kernel, has a silk attached to it. When a pollen grain lands on an individual silk, it produces a pollen tube that grows up the length of the silk and fertilizes the ovule. One to four days after a silk is pollinated and fertilization successful, the silk will detach from the developing kernel. Silks dry up and brown after fertilization. Silks do not detach from unfertilized ovules ie. those that will not make a kernel. Long silks that are still fresh are a sign of unsuccessful pollination. Unpollinated silks continue to lengthen for about a week after emerging from the husks before they deteriorate. With time, silks become less receptive to pollen and the likelihood of fertilization and kernel development decreases.
You can check for fertilization by unwrapping the husk from an ear and then gently shaking the ear. Silks from fertilized ovules will readily fall off. Ears from several locations throughout the field should be examined to get a good field estimate. The degree of success of fertilization and potential kernels can be estimated by the number of ovules without a silk attached.
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