Monitoring für Getreidekrankheiten in Bayern – mehrjährige Auswertungen über die Bedeutung der einzelnen Schaderreger

Since the year 1991, up-to-date data about the actual infestation situations of the most important fungal diseases have been made available to the official advisory service and to the farmers by means of the “Monitoring for cereal diseases”. The classification of infestation is taken according to the scientifically elaborated thresholds of the Wheat Crop System Bayern and the Barley Crop System Bayern, respectively. The extensive data material allowed an evaluation over several years for the various cultivated areas. The least importance in winter wheat had eyespot, brown rust und yellow rust. Most exceedings of the thresholds were caused by Septoria tritici and Drechslera tritici-repentis. On about one third of the examined locations, exceedings of the threshold could already be noted before the growth stage “flag leaf just visible”. According to the infestation situation, in more than half of the cases one treatment would have been appropriate. In the past five years, the net blotch caused by Drechslera teres has turned out to be the most important disease in winter barley. With some difference in importance followed Rhynchosporium leaf blotch, powdery mildew and brown rust. At almost 80% of the locations, threshold exceedings were registered until the growth stage “flag life ligule just visible” (BBCH 39). In the majority of cases, the infestation situation makes a single treatment in winter barley appearing reasonable. In the years 2001–2004 the main pathogen in spring barley had been powdery mildew, followed by Drechslera teres and Rhynchosporium secalis. The exceedings of the thresholds had been spread over a broad range of growth stages. In the past five years the infestation of fungal diseases in triticale has been low. However since 2005 an increase of infestation, especially of powdery mildew, has been registered. The evaluation of the results from the “Monitoring for cereal diseases” over several years allows to estimate the risk of the different fungi in the regions. From that, conclusions about the fungicide intensities required in the average of cases can be drawn.