Decision Support Systems for Detecting Aerial Potato Phytophthora infestans Sporangia in Northwestern Spain

Core Ideas Late blight outbreaks have a remarkable socioeconomic and environmental impact. The levels of late blight sporangia are highly dependent of the weather conditions. Aerobiological information is a useful tool to control late blight. Potato late blight caused by Phytophthora infestans (Mont.) de Bary has major economic impacts on this crop worldwide. Forecasting the risk of infection in potato (Solanum tuberosum L.) cultivars is indispensable for the management of this disease. Agronomic, chemical, statistical or mathematical methods are used to reduce the potato blight outbreaks, and decision support systems are considered a useful tool for integrated management of crops. This study aimed to investigate the effectiveness of different decision support systems (Smith periods, negative prognosis model, Fry system, Wallin severity values, WinstelCast system) to predict the risk of late blight on the A Limia plateau, the most important potato production area in northwestern Spain. The relationships between weather conditions and airborne sporangia were statistically analyzed. The study was conducted during seven crop cycles. The level of P. infestans sporangia was determined by conducting aerobiological sampling by using a LANZONI VPPS‐2000 volumetric trap. The maximum levels of sporangia were found during the vegetative stage of the crop, mainly during germination and leaf development. The aerobiological data and meteorological conditions of the zone suggest that the most effective models to forecast late blight in A Limia are negative prognosis and WinstelCast, considering that optimal relative humidity for the disease is more than 75%.