Relationship of Forage Quality to Developmental Parameters of the Fall Armyworm (Lepidoptera: Noctuidae)

Abstract

Nine developmental parameters for the fall armyworm (FAW), Spodoptera frugiperda (J. E. Smith), reared on ‘Coastal’ bermudagrass, Cynodon dactylon (L.) Pers., were regressed on commonly employed analytical tests of forage quality for cattle (i.e., crude protein and in vitro dry matter digestibility [IVDMD]). Highly significant r 2 values were obtained for the FAW parameters regressed on both crude protein and IVDMD. Regressions for crude protein and IVDMD on FAW biological parameters improved with fertilization of the bermudagrass. Similarly, regressions for crude protein and IVDMD on FAW biological parameters were highly significant, in most instances, at all ages of bermudagrass regrowth. The r 2 values for IVDMD declined with increasing age of the grass for most of the FAW parameters. Thus, improvements in bermudagrasses based on increased protein or digestibility are likely to increase their susceptibility to the FAW.