Wildflowers that serve as food supply for the parasitoid Microplitis mediator improve the effectiveness of biological control in a cabbage field

Abstract: Agricultural landscapes are a very suitable environment for crop herbivore pests, providing them an almost unlimited food source. On the other hand these fields are poor environments for the nectar feeding parasitic wasps, like Microplitis mediator (Haliday) (Hymenoptera: Braconidae). In the light of natural pest management it is therefore important to make the crop field more attractive for pests’ natural enemies, for example by adding wildflowers along or inside the crop field. Experiments identifying attractive and beneficial wildflowers were all conducted under laboratory conditions. However, it is important to test their attractiveness also under field conditions, in order to understand their suitability to biological control. We tested the distance-dependent attractiveness of a wildflower strip placed along a cabbage field using a Y-tube field olfactometer. Simultaneously we collected air samples that we analysed in the laboratory to link the behavioural response to the volatile profile of the air. We demonstrate that the selected wildflowers are attractive for M. mediator also under field conditions, supporting the usefulness of these flowers in biological pest control.