during her adult life of 18 to 24 days, a female can lay a total of 400 to 600 eggs. the female european corn borer moth first lays eggs in june. the eggs are laid on the underside of corn plant leaves near the midvein. around 90% of the eggs are laid on the leaf just below the primary ear leaf, and an equal number of eggs are laid above and below this leaf, with a slight bias towards the lower leaves. the egg masses are all laid within five leaves of the central ear leaf. brood sizes range from 15 to 30 eggs and egg masses are about 6 mm in diameter. the period of egg laying is about 14 days with an average of 20 to 50 eggs per day.