NegFry - DSS for the chemical control of potato late blight - results of validation trails in Tartu

Potato late blight, caused by the oomycete fungus Phytophthora infestans (Mont.) de Bary is the most destructive disease affecting the potato worldwide. For controlling the disease, most manuals recommend that growers apply fungicides at regular intervals of 8-10 days from the time of row closing until the end of the growing season. The NegFry model was used for timing the chemical control of potato late blight. The NegFry model is based on two existing models, the 'negative prognosis', for forecasting the risk of primary attacks, and a model for timing subsequent fungicide applications during the season. The main objective of NegFry is to get high yield and quality with minimum use of fungicides. Present work underscores that NegFry has given a positive result by timing the first spraying for anticipation of the infection and by optimizing the number of treatments for late blight control.