The pathogen Venturia inaequalis is the most important disease in apple growing. The prevention of infection by ascospores during the primary season is basis of any successful measures against apple scab. In this study the natural progress of the primary season in 2015 has been recorded by the use of a volumetric spore trap and the ventilation method for detecting the potencial of ascospores. Both, a shift in the primary season as well as a significant increase in the total number of ascospores were observed. Based on the natural spore flight simulation models to predict or identify infectious events, the programs SCHORF, SIMSCAB and the forecast of apple scab of the German Weather Service, were evaluated. All infection periods which took place have been recognized only by the SIMSCAB program. Based on the calculations of each model a further trial was made to compare an exclusively curative or purely protective strategy to control apple scab. The results showed that the exclusive use of protective fungicides showed the best success against apple scab. In addition to this, the effect and development of resistance of fungicides with the active substance anilinopyrimidines was tested in a second trial. It was observed that the fungicides scala and chorus didnt control the apple scab successfully. The sensitivity analysis showed a strong development of resistance to the active substance cyprodinil. In another experiment, a newly developed methodology to control the quality of occurred infections was tested. The infections as a result of events with rain were analyzed directly on the trees inside the orchard. The consideration of long shoots within the orchard is supposed to represent an alternative to the very expensive tests with container plants.