Abstract
Aphids alter plant development and can transmit viruses, thus representing a major threat for crops. Aphids may be controlled through cultural practices, however classical agronomic and ecological models are not suitable to explore their effects on plant pest interaction. Generally, the former do not explicitly consider the dynamics of pest, the latter have a too simplistic representation of the plant. In the present work, we extended a classical plant growth model, describing carbon and nitrogen assimilation and allocation, by integrating the population dynamics of an aphid population and the development of plant defences. We calibrate the model against data of peach Prunus persica subjected to different fertilization and irrigation regimes, infested by the aphid Myzus persicae. Our results suggest that aphid infestation induces the plant to produce defensive compounds that impair aphid ingestion and fecundity. Our model, parametrized for the peach-green aphid system, shows that all these apparently contrasting empirical evidences can emerge from the same biological principles governing plant-pest dynamics and that both plant vigour and plant stress hypotheses can find support when observing a plant-pest system.