Sweet corn is a heavy feeder, Lhowells. A picture would help to confirm, but right now the top suspect is nitrogen deficiency. Depending on how far gone it is, you might be able to rescue it with an application of fish emulsion, or Miracle-Gro, according to bottle directions. Slower acting preparations, such as fish, blood, and bone, may not work fast enough.
Other things to check would be the soil pH--less than 6.5 is bad--and the amount of sun it is getting--less than 6 hours a day is bad.

Thanks I do feed it an organic liquid feed but I will try the ph test and go from there thank you