PODYAM: a modeling framework for simulating population dynamics in agricultural mosaics

Integrated Pest Management (IPM) requires that several control methods be combined in order to control simultaneously several pests (weeds, diseases, animal pests), which can interact among themselves. Furthermore, some pests can disperse among fields while others may remain in the field during part of the next crop's cycle, adding possible interactions between pests of different crops or different cropping systems. Many models have been developed to predict disease epidemics and insect pests' population dynamics and to help design control strategies for a single pest on a single crop. But it is often difficult to design IPM strategies based on these models because of the lack of common formalisms or even common state variables between the different models. We propose a modeling framework in which any pest or disease could be simulated, allowing detecting antagonisms or synergies between strategies aimed at controlling different pests. Our main interest is in predicting the effect, on aerial diseases and pests, of the configuration of different control strategies in agricultural landscapes. Conclusion: The modeling framework proved to be generic enough to include three models that were developed with different formalisms (compartment model, age-structured population model, complex model with compartments and empirical relationships), with organisms defined at different scales (pixel, field). The first simulations confirmed that there is a trade-off between the control of blackleg by soil tillage and the biological control of pollen beetle by its parasitoid. In the future, this framework will be coupled with a database of equations and parameters of demographic models for several pests and natural enemies, among which to choose in order to build easily multi-pest models which could be used to design IPM strategies at the landscape scale.