Mesocosm experiments to assess the transmission of Pandora neoaphidis within simple and mixed field margins and over the crop-margin interface

► The effect of field margin plant composition on fungal transmission was assessed. ► Transmission of the fungus Pandora neoaphidis was greatest on a mixed field margin. ► Oviposition by the parasitoid Aphidius ervi was greatest on a simple field margin. ► Both species moved bi-directionally over the crop-margin interface. ► Field margins could be sources and sinks of both aphid natural enemies.