Cotton plants defend against feeding injury from the beet armyworm, Spodoptera exigua, by direct and indirect (incurred through natural enemies of herbivore) resistance, both of which can be systemic and inducible. Numerous studies have demonstrated that plant signals are transmitted upward in the cotton plant, but no attempts have been made to examine the potential that the systemic response is transported downward in cotton. In lima bean, however, systemic resistance has been demonstrated to move down the plant and through rhizosphere to benefit neighboring conspecific plants. Therefore, we examined the direction of systemically induced resistance in cotton using the beat armyworm as an eliciting herbivore. In addition, we evaluated the roles that herbivore density and herbivory duration play in the process of induction and the systemic response in cotton plants. Plants should be favored to respond differentially to variations in the magnitude and duration of defoliation because resistance induction is assumed to be costly.