Differential growth of fall armyworm larvae (Lepidoptera: Noctuidae) reared on three phenotypic regions of whorl leaves from a resistant and a susceptible maize hybrid

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 and in the other, they were fed reconstituted diets containing ground lyophilized leaf tissue from three phenotypic leaf regions of both hybrids. Results of the two bioassays were similar. Differences in larval weights were found for those larvae fed tissue from leaf regions within and across hybrids. The largest differences among treatments were found within the resistant hybrid, thus showing that regions of the same whorl leaf differ in suitability of food source for larval growth.