Modelling the effects of downy mildew on grapevine yield (Vitis vinifera L.).

A mechanistic simulation model of grapevine growth was coupled to a model of downy mildew populatione dynamics to evaluate the effetcts of this pathogen on grapevine yield. Damages determined by artificial epidemics the efffects of this pathogen on grapevine yield. Damages determined by artificial epidemics with differente timing (budbreak, bloom and veraison) and severity of first infection (1% an 10% of injured leaf surface) have been explred over thr years. The results showed differences between years in simulated damage (0.1% to 58% yield losses), which were mainly due to varying weather conditions and partly due to differences in timing and severity of first infection.