Factors responsible for corn earworm, Heliothis zea (Boddie), resistance in 6 resistant sweetcorn inbreeds and varieties, 1 extremely resistant starchy variety (Zapalote Chico), and Golden Cross Bantam T Strain were studied over several years. Over 5 years there were consistent differences among varieties in amount of earworm damage; Zapalote Chico, U.S. 34, and pajamaca were outstandingly resistant. During 3 years there were no consistent significant differences in numbers of eggs laid on 3-day-old silks of the varieties although a significant F value was obtained in 1 year. In 2 years, slitting the husk tips or removing the distal 1 inch of tip at first silking significantly increased susceptibility in the varieties as a group, and in most varieties individually. This evidence for resistance owing to husk tightness is of renewed interest in light of the failure of recent studies to substantiate the presence of chemical resistance factors. In 1 season, there was no significant difference in injury to starchy as compared with sugary ears on similar genetic backgrounds.