Effects of different fungicides on the infection by Passalora malkoffii with respect to the fruit yield and quality of aniseed (Pimpinella anisum L.) in Germany

In 2009 and 2010 field experiments with anise (Pimpinella anisum L.) were conducted in the experimental station Gross-Gerau (Justus Liebig University Giessen) to evaluate the efficacy of fungicides on the disease of anise blight (Passalora malkoffii (Bubak) U. Braun). It was found that the application of mancozeb + metalaxyl-M as well as azoxystrobin + difenoconazole significantly reduced the incidence of Passalora malkoffii compared with other applied fungicides and the untreated control. This was consistent over the two growing seasons with different levels of disease in each. Contrary to 2009, azoxystrobin + difenoconazole caused significant changes in yield contributing parameters including the number of primary branches/plant, umbels/plant, fruits/plant and fruit weight/plant in 2010. The accession from Pharmasaat produced a higher fruit yield than that one from Enza Zaden. The essential oil concentration of anise fruits was affected by fungicides as well as by cultivars only in 2010. Azoxystrobin + difenoconazole- and fosetyl-treated cultivars produced significantly higher essential oil concentrations than those treated with other fungicides or than the control. Fosetyl application resulted in a higher content of trans-anethole compared with other treatments in both growing seasons. According to our results the application of the fungicide combination azoxystrobin and difenoconazole can be an efficient approach to reduce the severity of anise blight and to improve the fruit yield of aniseed.