Climate Change and its Impact on the Conditions of Late Blight Occurrence

Abstract The paper is focused on the evaluation of trends in weather indicators influencing conditions for late blight occurrence, and subsequently on trends in the first treatment forecasts, number of infections, and number of infection days. The processing covering the period 1975–2016 was done with a higher density of points for the Czech and Slovak Republics and a lower density for European regions with more important distribution of potato growing on arable land. The obtained results show an unambiguous statistically significant trend in the increase of minimum temperature by around 0.5°C per 10 years; contrarily, no more significant trends were recorded for air humidity. For precipitation no statistically significant decreases were found at any of the processed localities, increases were rarely detected. Considering the number of days with precipitation, for the western part of the studied territory rather increases, while for the eastern part stagnation, and for Ukraine decrease in days with precipitation were recorded. Trends in the processed characteristics using the index method of late blight indicate a statistically more significant earlier onset of the first treatment especially at Czech localities; however, at most localities a slight increase in the number of infection periods and in the number of days with infection pressure was found.