A phenological model for the European corn borer Ostrinia nubilalis Hübner race with one generation per year was developed and validated by Agroscope. This model replaces the previous time-consuming method for predicting the optimal time for implementing measures to control the corn borer (Derron and Goy 2006). The conventional method consists in predicting the flight of the adult insects by repeatedly determining the pupation rate in piles of maize stubble under semi-field conditions. The model developed by Agroscope was parameterised with the help of laboratory data. The model was calibrated and validated under semi-field and field conditions on the basis of data gathered over 29 years of observation of pupation and emergence. With monitoring data of the flight it was possible to compare the simulations with the observations in the field, and to evaluate the simulations in terms of their reliability for predicting flight. In the large majority of cases, the simulations were as reliable as the observations. On average, the simulated emergence was 6,9 degree-days earlier in Changins, and just 0,5 degree-days earlier at the other Swiss sites. Even if the model is slightly less accurate than the observation – especially in years with an exceptionally dry spring – the results of the simulations are conclusive and allow for a reliable prediction for the release of parasitoids wasps, thereby supporting this model.
Development and validation of a phenological model for the european corn borer