Unexpected lack of influence of tree rows on the dynamics of wheat aphids and their natural enemies in a temperate agroforestry system

摘要: Trees at low density and cereals may be combined in silvoarable agroforestry systems: tree rows their companion vegetation introduce an heterogeneity the cropped field that modify dynamics of insects crop pests predators. This hypothesis was tested tree-wheat systems by monitoring aphids predators for two years southern France, fields 2006 one 2007. Tree row diversity either suppressed weeding or stimulated seeding flowering species could attract adult aphids. The were recorded tiller sampling yellow trap monitoring. Between 3500 5000 collected from each studied field. Surprisingly, no differences evidenced on both between monocropping plots, nor weeded flowered plots. induced probably not strong enough to alter populations dynamics. A high landscape area due nearby forest patches fallows have blurred impact lines. Different results expected areas with lower biodiversity like cereal zones.