Effect of Cuticular Lipids From Silks of Selected Corn Genotypes on the Development of Corn Earworm Larvae

Abstract

Eleven genotypes of corn, Zea mays L., known to vary in their resistance to silk-feeding by larvae of the corn earworm, Helicoverpa zea (Boddie), were used to study the effect of corn silk cuticular lipids on larval growth and development. Growth of the corn earworm was significantly enhanced when larvae were reared on meridic diet containing corn silks from which the cuticular lipids had been removed. Growth of larvae reared on a diet containing unextracted silks from genotypes ‘Stowell's’ ‘Evergreen’, ‘Pioneer 3369A’, and ‘PI340856’ was not affected. When the cuticular lipid extracts of corn silks were added to a meridic diet, no significant differences were found in the weight of 8-day larvae, time to pupation, or days to adult emergence for larvae reared on silks of several corn genotypes. However, the weight of pupae was significantly less when larvae were fed a diet containing cuticular lipids extracted from silks of three corn genotypes ‘Stowell's Evergreen’, ‘GE37’, and ‘Zapalote Chico 2451#(P)C3’ than the weight of pupae from larvae that fed on the control diet.