Effectiveness of short-term numerical weather prediction in predicting growing degree days and meteorological conditions for apple scab appearance

Abstract

© 2015 Royal Meteorological Society This study assesses the effectiveness of short-term numerical weather prediction (NWP) in predicting the accumulation of growing degree days (GDDs) and meteorological conditions for apple scab appearance. Apple scab is the most frequent and harmful apple disease caused by the fungus Venturia inaequalis. Using the 30 days of NWP weather forecast and observed data for March 2011, representative data sets based on 24, 48, 72 and 96 h forecasts were designed. The results obtained for four lowland locations in Serbia and one slightly hilly location in Austria indicate that, on a monthly basis, there is a relative deviation of up to 20% in the GDD predictions above 0 °C and a 40% relative deviation in the GDD predictions above 5 °C. In contrast to the slightly hilly location, the apple scab appearance predictions based on the NWP in lowland locations correspond well with the results obtained using observed meteorological data. This indicates that short-term NWP is potentially effective in predicting apple scab appearance and has a slight advantage in lowland regions.