Data from: Biological pest control and yields depend on spatial and temporal crop cover dynamics

1. Modern agricultural landscapes are dynamic systems with interannually
changing proportions of different crop types. However, the effects of
spatiotemporal changes in crop area on crop yields and
crop–herbivore–antagonist interactions have been rarely considered, in
contrast to documented beneficial effects of semi-natural habitats on
biological pest control at local and landscape scales. In this study, we
examined how the proportion of oilseed rape (OSR) fields in a landscape
and the annual increase or decrease in OSR cover due to crop rotation
affect OSR herbivores, their natural enemies and crop yield. 2. During two
study years, we examined the abundance of adult and larval pollen beetles,
parasitism of pollen beetle larvae by a parasitic ichneumonid and crop
yields (seed weight per plant) in the edge and centre of 36 OSR fields.
The fields differed in the proportion of OSR in the surrounding landscape
at 1-km radius and in the interannual change in the proportion of OSR from
the previous year to the respective study year. 3. Adult pollen beetle
abundance decreased in one study year and larval pollen beetle abundance
and parasitism rates decreased in both study years with spatially
increasing OSR proportion in the landscape, indicating dilution effects on
both trophic levels. Crop yield was positively affected by spatially
increasing proportions of OSR. An interannual increase in the proportion
of OSR led to the dilution of pest species, but had no significant effect
on yield or parasitism rate. 4. Synthesis and applications. The negative
effects of pollen beetles on yields despite regular insecticide
applications underpin the need for improved techniques for controlling
this pest. Our results emphasize the potential to enhance crop yields by
the management of spatiotemporal crop cover dynamics within landscapes. We
recommend that future management schemes should coordinate the spatial
aggregation and annual dynamics of oilseed rape (OSR) cover in a landscape
as a potential way to reduce pest impacts in intensively managed OSR
fields.