Landscape complexity and field margin vegetation diversity enhance natural enemies and reduce herbivory by Lepidoptera pests on tomato crop

Abstract

Agricultural intensification may lead to higher pest pressure through the loss of natural plant assemblages, and associated reduction in natural enemy diversity, while providing increased crop area. We investigate the influence of field margin vegetation and landscape complexity on natural enemy diversity and crop damage caused by two Lepidoptera tomato pests (Tuta absoluta and Noctuidae). At the local scale, fields were bordered with herbaceous field margins of varying vegetation diversity. At the landscape scale, these fields were set in landscapes with increasing landscape complexity. Margin vegetation diversity was higher in landscapes with lower arable land cover, and was associated with increased floral resources and enemy diversity, with the latter being negatively related to T. absoluta-caused fruit injury. Total crop damage increased with arable land cover. These results imply that the suitability of farming practices for the conservation of natural enemies and pest control services is influenced by the landscape context.