The field experiment carried out in Winna Góra compared the efficacy of fungicide programs applied in accordance with the NegFry and Routine systems. The results of2002 validation achieved in Winna Góra showed that NegFry model forecasting the late blight occurrence is useful in Polish climatic conditions. Compared with routine treatment schemes, NegFry recommended fewer treatments without significant reduction of yield thus potato protection according to NegFry was more cost-effective than according to Routine system. Basing on these facts the NegFry decision support system can be recommended for Polish climatic conditions.

The NegFry model used for timing the chemical control of potato late blight was validated in field trials at Bonin in the years 2001-2002 (4 trials). In these trials the number of fungicide treatments recommended by NegFry was about 34.5% lower (on average) than the number of treatments in a routine spraying scheme. This reduction was mostly the results of a delay in the time of the initial fungicide application and longer spraying intervals recommended by Negfry.