Submitted to: Florida Entomologist
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/1/1999
Publication Date: N/A
Interpretive Summary: Fall armyworm (FAW) larvae can seriously damage whorl stage corn by consuming large amounts of leaf tissue. Corn germplasm lines that resist leaf feeding by this pest have been developed and released. The objective of the present study was to determine if regions within the whorl tissue leaves of a resistant and susceptible corn hybrid vary for their suitability for FAW larval growth. Our results showed that suitability of tissue for larval growth differed among leaf regions within the hybrid and across hybrids. The largest differences in growth were found within the resistant hybrid, thus showing that regions of the same whorl leaf differ in suitability as food for larval growth. This study provides a better understanding of the susceptible and resistant whorl leaf as it relates to larval growth and the presence and intensity of resistance factors. Also, our results provide a new opportunity for determining the chemical and physical factors. Determining these factors will help in development of resistant corn hybrids responsible for the resistance.
Technical Abstract: Two laboratory bioassays were conducted to determine the effect of feeding selected whorl leaf regions of a resistant and a susceptible maize, Zea mays L., hybrid on fall armyworm, Spodoptera frugiperda (J. E. Smith), growth. In one bioassay, larvae were fed fresh excised whorl leaf tissue. In the other, they were fed reconstituted diets containing lyophilized leaf tissue from three leaf regions of both hybrids. Results of the two bioassays were similar. Differences in larval weights were found for larvae fed tissue from different leaf regions within and across hybrids. The largest differences were found within the resistant hybrid, showing that regions of the same whorl leaf differ in suitability as a food source for larval growth.