MODELING DAMAGE ON MAIZE BY THE EUROPEAN CORN-BORER, OSTRINIA-NUBILALIS

The European Corn Borer (ECB), Ostrinia nubilalis Hbn. (Lepidoptera: Pyralidae), is a major pest of maize in many countries. Yield losses caused by larvae of this insect depend mainly on the extent of cavity damage, the timing of tunnelling, and their within-plant distribution. To describe these factors, a mechanistic model of cavity appearance is proposed here. It takes into account the main biological processes which determine damage. These are the development, mortality and within-plant distribution of the ECB larvae. The model has been estimated and tested on field data collected at INRA-Versailles in France. Model fittings showed that (i) creation and lengthwise extension rates of cavities per larva depend on location and instar of the larvae, and that (ii) only instars 4 and 5 make cavities. This model described, with a high precision level, the appearance and lengthwise extension of cavities over time and their within-plant distribution for two maize varieties, several infestation dates and levels, and various climatic sequences.