Plant Resistance and Its Effect on the Peritrophic Membrane of Southwestern Corn Borer (Lepidoptera: Crambidae) Larvae

Abstract The southwestern corn borer,Diatraea grandiosella Dyar (Lepidoptera: Crambidae), is a serious pest of corn,Zea mays L., in the southern United States. Corn germplasm lines with conventional genetic leaf-feeding resistance to this pest, the fall armyworm,Spodoptera frugiperda (J.E. Smith), and other lepidopterans have been released to the public by USDA–ARS scientists located in Mississippi. Recent studies suggest the insect resistant lines disrupt the integrity of the peritrophic membrane of the fall armyworm. The objectives of this study were to investigate any morphological differences in the structure of the peritrophic membrane of southwestern corn borer larvae feeding on resistant and susceptible corn hybrids and to quantify the damage. Larvae were reared under field and laboratory conditions on three corn hybrids (two resistant and one susceptible). Scanning electron microscopy was used to examine the peritrophic membrane for abnormalities such as holes or tears and to count the holes or te...