Fall Armyworm Symposium: Seasonal Distribution, Response to Host Developmental Stage, and Screened-Cage Performance of Archytas Marmoratus (Diptera: Tachinidae) and Ophion Flavidus (Hymenoptera: Ichneumonidae) on Spodoptera Frugiperda (Lepidoptera: Noctuidae)

H. R. Gross, S. D. Pair


Laboratory and field studies with Archytas marmoratus (Townsend) and Ophion flavidus Brulle were designed to provide a better understanding of their individual and combined impact on the fall armyworm, Spodoptera frugiperda (J. E. Smith). The highest percentage of natural parasitism by A. marmoratus and O. flavidus on S. frugiperda occurred from late April through mid-June during 1985-1986 near Tifton, Georgia. Ophion flavidus parasitized 4th, 5th, and 6th instars with equal success, but were minimally successful in completing development on late 6th instars. Archytas marmoratus were equally successful in completing development on 3rd, 4th, 5th, and 6th instars. When S. frugiperda were multiply parasitized, A. marmoratus did not successfully compete with O. flavidus. When two A. marmoratus and two O. flavidus females, or four A. marmoratus and four O. flavidus females were released against 5-6th instar S. frugiperda in whorl-stage corn within 1.8 @? 1.8 2? 1.8 m screened cages, the number of emerged S. frugiperda adults of the subsequent generation was reduced by 50.6 and 92.1%, respectively. With the development of economical methods for mass propagation of A. marmoratus and/or O. flavidus, will come primary opportunities for advancing biologically based strategies for managing S. frugiperda.

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