Bio-economic modeling of wine grape protection strategies for environmental policy assessment

This research had two objectives. The first was to model the behaviour of wine producers, and the second was to assess the effectiveness of policies designed to reduce pesticide use in viticulture. We modeled the decisions of producers aiming to maximize their expected income while subject to a number of constraints and phytosanitary risks. We also examined the impacts of different protection strategies targeting downy mildew, the main grape disease in European Atlantic vineyards. The Vineyard model for Environmental Policy Analysis (VINEPA) model is a multi-periodic stochastic programming model based on panel data of about one hundred representative winegrowing farms from the Farm Accountancy Data Network in the Bordeaux region. The response of vines to fungicide treatments against downy mildew was simulated through the downy mildew potential system, an epidemiologic model initially developed for decision support, using data from multiple weather stations along with special plots of untreated vines, monitored weekly over a 10-year period. The VINEPA model accurately reproduced the current chemical protection strategies in the region. Simulations were then carried out for different types of taxes (ad valorem and volume based) at different rates. In addition, we analysed the effects of policies on spraying practices, along with their potential impact on investment in precision technology equipment.