Spodoptera frugiperda (Lepidoptera: Noctuidae): Deterrence of Oviposition by Aqueous Homogenates of Fall Armyworm and Corn Earworm Larvae Applied on Whorl-Stage Corn 1

Abstract

Aqueous homogenates of terminal-instar larvae of fall armyworm, Spodoptera frugiperda (J. E. Smith), and corn earworm, Heliothis zea (Boddie), were evaluated against field populations of S. frugiperda in whorl-stage field corn near Tifton, Ga. The number of fall armyworm egg masses oviposited on corn treated with either 1.0 or 0.1 larval equivalent per plant of either fall armyworm or corn earworm was significantly lower than that of controls. Multiple applications of 1.0 larval equivalent per plant of fall armyworm and corn earworm reduced the subsequent establishment of fall armyworm larvae by 66.5 and 63.6%, respectively. Plots treated one, two, or three times weekly with 1.0 fall armyworm larval equivalent per plant all received significantly fewer fall armyworm egg masses than did the control plants. Plots treated two or three times weekly contained significantly fewer subsequent fall armyworm larvae-infested plants than did plots treated once weekly. Although deterrent mechanisms have not been specifically identified, semiochemicals associated with terminal-instar larvae of fall armyworm and corn earworm and/or their byproducts may be responsible for inducing fall armyworm females (and, to a lesser extent, newly emerged fall armyworm larvae) to seek uncontaminated sites for oviposition and establishment, respectively.