Suitability and Profitability of a Cereal Aphid for the Parasitoid in the Context of Conservation Biological Control of in Orchards.

The use of cover crops can promote the abundance and early arrival of populations of natural enemies. Cereal cover crops between orchards rows could encourage the early arrival of the parasitoid , as they offer alternative winter hosts (e.g., ), enhancing the control of in spring. However, the preference for and suitability of the alternative host must be addressed beforehand. To evaluate the potential of this strategy, we assessed host preference using behavioural choice tests, as well as no-choice tests measuring fitness traits, when developing on both host species. One source field for each aphid population from the above hosts was chosen. There was a clear choice for compared to , independently of the source, probably due to more defensive behaviours of (i.e., kicks and escapes). Nevertheless, both aphid species were suitable for parasitoids' development. The female progeny developed on were larger in size, irrespective of their origin. According to our results, in peach orchards with cereals sown between peach trees during the autumn, where we expect when populations will no longer be available during spring, should be able to switch to .