A preliminary approach for modelling the effects of cropping systems on the dynamics of broomrape (Phelipanche ramosa) in interaction with the non-parasitic weed flora

Abstract : The current decrease in herbicide use may increase and diversify weed flora incrops as well as companion bioagressors spreading via weeds. Among these bioagressorsisPhelipanche ramosa(L.) Pomel, a parastic plant which is very harmful on oilseed rape.The objective of the present work was to develop a new model (called PheraSys) of theeffects of cropping systems on parasite dynamics, in interaction with non-parasitic weedhosts. The structure of this first model version was based on models developed for otherparasitic plants and on FlorSys which quantifies the effects of cropping systems on non-parasitic weed flora. PheraSys was parametrized with preliminary values from literatureand expert opinion, connected to FlorSys for weed host predictions and used to simulateparasite dynamics in a few contrasting cropping systems.