Each year some fields have corn emerge prior to the application of preemergence herbicides. Many preemergence products registered for corn allow for application after corn emergence; however, Axiom, Balance, and Epic do not include early postemergence applications on the label. Consult labels to determine specific restrictions concerning delayed preemergence applications. The performance of preemergence herbicides is less consistent when application is delayed, primarily due to weeds emerging prior to exposure to the herbicide.