Modeling Induction of Diapause in North American Ostrinia nubilalis (Lepidoptera: Pyralidae) Populations

Abstract

A general model for predicting diapause induction in most North American populations of European corn borer, Ostrinia nubilalis (Hubner), was created by statistically testing the influence of scotophase, civil twilight (the period before sunrise or after sunset when the sun is 6° below the horizon), temperature, and latitude in equations calibrated with and validated against laboratory and field data. The best equation in equations calibrated hours of darkness per day, mean temperature, and latitude in decimal degrees. To predict diapause induction in the field, a larval maturation model and a function for determining the response of different larval instars must be calculated along with the basic equation. In the field, scotophase should be calculated by subtracting daylength and civil twilight from 24 h. The overall model explained about half the variability in the independent data for European corn borer populations in North America between 30 and 50° N latitude.