ABSTRACT
Hedgerows benefit biological control through the provision of resources for natural enemies including shelter, food (invertebrate prey, pollen, nectar, seeds) and a refuge from potentially harmful agricultural operations. In some landscapes they are also the predominant non-crop habitat. Despite these attributes, research into their value for biological control has largely focused on the herbaceous plants of the hedge base rather than the shrubs or trees. Both components support a diverse and often high abundance of natural enemies that migrate or spill over into the adjacent crop and landscape. In comparison to measurements of natural enemies, evidence that they contribute to pest control is lacking, and this, along with the limited ability to change their perennial plant composition to favour more natural enemies, may explain why they are less well investigated or considered in integrated pest management programmes.
