A RELACS project - The overall aim is the development of novel copper alternatives and integration in crop protection strategies to replace copper (no copper strategies) or to limit the use of copper (low copper strategies) in organic plant production. The specific objectives related to this Deliverable are to develop copper alternatives according to the companies involved in the project and based on this, to develop strategies to reduce copper use under field conditions on crops with high relevance, in particular grapevine, apple and glasshouse crops (e.g. tomato, cucurbits) as well as on minor crops such as roses and others. Four copper alternatives (test product, TP) were provided by the RELACS partners (named TP1, TP2, TP3 and TP4), and a product from outside RELACS was tested against apple scab (TP5). Low/no copper strategies in grape vine: Results showed that a significant reduction of copper in grapevine is possible and best results were obtained when copper and TPs are applied in tank mixture at the most susceptible phenological phases, where high infection risks prevail. Thus, this strategy (TP+Cu strategy) will be further evaluated on farm in order to maximise product efficacy and minimise the use of copper. Low/no copper strategies in apple: Results showed that a significant reduction of copper in apple is possible and best when copper is used only in primary season of apple growing. During that time, the application of copper can be optimally timed by strictly following infection forecast from decision support systems, therefore only treating when necessary. TPs should be applied in tank mixture at the most susceptible phenological phases, where high infection risks prevail. Thus, this strategy (TP+Cu strategy) will be further evaluated on farm in order to maximise product efficacy and minimise the use of copper. Low/no copper strategies in vegetables: For cucumber, mainly TP2 was selected for on-farm trials as stand-alone treatment. For tomato, TP2 and TP3 were selected. In on-farm trials the potential of these TPs should be evaluated in order to reveal their copper replacement potential under practice conditions. Low/no copper strategies in minor use specialty crops: For roses results were encouraging. All four TPs had a positive effect on rose oil yield in the 3 different years. Different strategies for replacement or reduction of copper use in organic cultivation of roses can be developed on this basis. For raspberries final conclusions cannot yet be drawn.
Annegret Schmitt (JKI), Ursula Wenthe (JKI), Hans-Jakob Schärer (FiBL), Michele Perazzolli, Oscar Giovannini (FEM), Stoilko Apostolov (Bioselena)