Managing field margins for hoverflies.

Abstract

In this paper we consider the effectiveness of providing flowering strips along the border of fields to augment the density of aphidophagous hoverflies. It is now fairly well established that additional floral resources can increase the local density of adult hoverflies. The evidence that higher densities of adult hoverflies actually promote significant control of aphid populations is however rather equivocal and the possible reasons for these incongruous results are discussed. Finally, we address some of the wider implications of this management programme including a discussion of its economic justification and the possibility of undesirable side effects.