Modeling within-plant distribution of European corn borer (Lepidoptera : pyralidae) larvae on corn for pretasseling infestation

To quantify yield losses of corn, Zea mays (L.), caused by larvae of the European corn borer, Ostrinia nubilalis (Huebner) (Lepidoptera: Pyralidae), a model describing the within-plant distribution of larvae is proposed and discussed. This paper is restricted to the interorgan and vertical distribution of larvae for pretasseling infestation. Field data collected at Versailles were used to study larval distribution and to estimate and test the model. The model proposed is based on four hypotheses deduced from field data: larval distribution in the tassel is influenced mainly by corn development; distribution in the ear of fourth and fifth instars depends on infestation date; distribution of first instars in the ear is conditional upon ear appearance; and vertical distribution of larvae in vegetative organs depends on corn development. For the 11 infestation conditions, the proposed mathematical model used to quantify the relations between larval distribution and main factors (corn development, infestation conditions) allows the percentages of larvae in ear, tassel, and internodes to be described with a precision of 10-15%.