Entwicklung eines biologischen Pflanzenschutzmittels aus Süßholz zur Anwendung an Freilandgemüse

Summary

The plant extract from Glycyrrhiza glabra (liquorice) has a proven efficacy against Oomycetes in several vegetable crops under controlled conditions (greenhouse), however the liquorice extract shows varying efficacy when applied in the field. Therefore, a joint project funded by the Federal Institute for Agriculture and Food (Bundesanstalt für Landwirtschaft und Ernährung, BLE) aims to develop a plant protection product based on liquorice extract, which is highly effective in the field against Pseudoperonospora cubensis and Phytophthora infestans. Semi-field systems in cucumber and tomato have been established to test novel extract formulations on rainfastness and UV stability as well as on application parameters to maximize disease control. The results of three selected liquorice extract formulations demonstrate the effects of simulated rain and sun exposure on the biological activity in the semi-field systems. None of the tested formulations proved efficiently stable to rain and sun exposure. In addition, first results of a cucumber field trial will be presented. The testing for more stable liquorice extract formulations will be continued.