THE DISEASE MANAGEMENT CHALLENGES OF 2012 Kerik

Apple Scab and Powdery Mildew in NY during the 2012 season The 2012 growing season came unexpectedly in early March during a period of warm weather following a warmer than usual winter. The early season was characterized by number borderline apple scab infection periods until the beginning of April a time when most model predictors were in agreement. The spring freeze hit during bloom which was flanked by brief periods of colder wet weather. Aside from destroying the apple crop, this weather resulted in another series of borderline infection periods. Ascospores were mature there was adequate leaf wetness, but the temperatures were cool for the time of the year. It was situation that was never modeled during the research that investigated the biology and epidemiology of the apple scab fungus, Venturia inaequalis. Not unlike 2011, there were drought conditions from late June to July resulting in high pressure for powdery mildew. By harvest rains were heavy and disease pressure for summer diseases was high. With the loss of the crop there was less of an incentive to apply fungicides for apple scab and mildew and with the borderline infection periods, western NY seemed to experience varying degrees of disease control failures and losses depending on which places still had a crop.