Effect of High-Amylose Field Corn on Larval Growth and Survival of Five Species of Stored-Grain Insects1

Abstract

Five species of stored-grain insects were reared on field corn seed averaging 60, 70, and 25% amylose (normal corn). The effect of amylose on larval survival was determined by the total number of adults produced. The effect on larval nutrition was ascertained by the average adult weights. The amylose content of corn did not affect either larval nutrition or survival of the lesser grain borer, Rhyzopertha dominica (F.), or the red flour beetle, Tribolium caslaneum (Herbst). High-amylose corn adversely affected larval nutrition of the granary weevil, Sitophilus granarius (L.); the rice weevil, S. oryzae (L.); and the An-gonmois grain moth, Sitotroga cerealella (Olivier). Larval survival on 70% amylose corn was disproportionately low for the granary weevil and disproportionately high for the rice weevil and the Angoumois grain moth. Because the 60 and 70% amylose corn varieties were developed under different breeding programs, larval survival may have been influenced by resistance factors other than the amylose content of the corn seed. Whether the granary weevil, rice weevil, and the Angoumois grain moth may possibly be used in selecting high-amylose field corn seed for a high-amylose cornbreeding program may depend upon the homogeneity of resistance factors, other than amylose content, of the corn seed itself.