Characterization of Cuticular Lipids from Cultivated and Wild Peanut Species and Their Effect on Feeding by Fall Armyworm (Lepidoptera: Noctuidae)1

The cuticular lipids from the adaxial and abaxial leaf surfaces of two peanut cultivars and four wild peanut species were isolated individually and characterized by combined gas chromatography-mass spectrometry. The two Arachis hypogaea peanut cultivars, Florunner and Southern Runner, and three of the wild peanut species A. ipaensis, A. paraguariensis, and A. diogoi had higher proportions of fatty alcohols on the adaxial leaf surface (17–37%) than on the abaxial surface (11–14%) and a higher percentage of n-alkanes on the abaxial surface (23–66%) than on the adaxial surface (15–30%). The wild peanut species A. villosulicarpa had high proportions of n-alkanes on both the adaxial and abaxial leaf surfaces. Scanning electron microscopy showed that leaf surfaces with high fatty alcohol content had a dense array of wax crystals while those with larger amounts of n-alkanes had an amorphous appearance. Fall armyworm, Spodoptera frugiperda (J. E. Smith), larvae were reared on meridic diet containing foliage from each of the peanut entries, diet with foliage from which the cuticular lipids had been extracted, and diet containing cuticular lipid extracts. Fall armyworm growth was enhanced when larvae were fed diet with A. ipaensis foliage from which the surface lipids had been removed.