Effect of organic and conventional practices on the insects natural enemies communities in agricultural landscapes

Food security and biodiversity conservation are among the main challenges of modern agriculture. Organic Farming (OF) is considered as a promising type of production to meet these challenges due to the use of alternative practices on organic systems. In particular, biological control of pests by their natural enemies is considered as a possible way to reduce pesticide use in Conventional Farming (CF). The aim of this work is to describe the diversity of practices on winter wheat in organic and conventional farms, and to understand their effects on natural enemies, at field and landscape scales. Entomological surveys and agronomic surveys were carried out in forty fields (twenty under OF and twenty under CF) located in different landscape contexts. The results showed that both farmers under OF or CF implemented a diversity of management strategies on winter wheat, although the dichotomy between the two production types remained well marked. At the field scale, organic practices seemed to be more favorable to the presence of beneficial insects than conventional practices, suggesting a more effective biological control. However, no effect of the proportion of OF in the landscape context of fields was found