Evaluation of a revision of the BSPcast decision support system for control of brown spot of pear

The disease brown spot of pear (Pyrus communis L.) (BSP) is caused by the fungus Stemphylium vesicarium (Wallr.) E. Simmons. The economical losses caused by BSP are very important in several pear production areas of Europe including Spain, Italy, France, Portugal, The Netherlands and Belgium (Llorente and Montesinos, 2006). Control of BSP is based on fungicide applications during the growing season according to fixed schedules or timed using the BSPcast forecasting system. This model was obtained from experiments performed under controlled environment conditions and is based on a polynomial equation which relates disease severity with wetness duration and mean temperature during the wetness periods (Montesinos et al., 1995). A cumulative risk index (CR) is obtained by totaling daily infection risk values (R) for the past 3 days, and CR values of 0.4 or 0.5 are used to trigger fungicide applications. The model was evaluated and validated in different field trials in Spain and Italy under a wide range of orchard and climatic conditions (Llorente et al., 2000). BSPcast is currently implemented as a warning system in the agrometeorological network of the Plant Health Services of Catalonia (Spain) and of the Servizio Fitosanitario, Regionale Emilia-Romagna (Italy). The efficacy of BSP control using the BSPcast is similar to that achieved with the fixed fungicide spray schedule and provides an average of 30%