| Abstract: | The prognosis of phenological stages of grapevine, linked with the assessment of leaf area development, is a valuable tool in support of timely plant protection treatments as well as optimum canopy management. Warm weather conditions from May to July combined with copious water supply may lead to an enormous growth in leaf area, so that volatile active substances have to be applied at shorter intervals than normally required. In addition, certain phenological stages are of special significance for the planning of appropriate plant protection measures. The expected phenological stages can be computed 10–14 days before their occurrence based on weather data, a 7‐day forecast and long‐term climatological data. In order to test the reliability of procedures aided by model approaches illustrated in the literature, a 30‐year observation series was used as a basis for this study. For the prognosis, mainly maximum and minimum temperatures, computed global radiation and daily precipitation totals were used. The computations were supplemented by long‐term daily mean values of these parameters. |
