Managing biodiversity in field margins to enhance integrated pest control in arable crops ('3-D farming' project)
Published source details
Powell W., A'Hara S., Harling R., Holland J.M., Northing P., Thomas C.F.G. & Walters K.F.A. (2004) Managing biodiversity in field margins to enhance integrated pest control in arable crops ('3-D farming' project). HGCA report, 356.
Published source details Powell W., A'Hara S., Harling R., Holland J.M., Northing P., Thomas C.F.G. & Walters K.F.A. (2004) Managing biodiversity in field margins to enhance integrated pest control in arable crops ('3-D farming' project). HGCA report, 356.
This study is summarised as evidence for the following.
Plant grass buffer strips/margins around arable or pasture fieldsAction Link
Plant nectar flower mixture/wildflower stripsAction Link
Plant grass buffer strips/margins around arable or pasture fields
A replicated study in 2000 and 2002 in Dorset, UK (Powell et al. 2004) found that field margins dominated by grass species supported different invertebrate communities in the adjacent crop to margins dominated by wildflower species. In 2000, margins dominated by grass species were associated with ground beetles (Carabidae); Bembidion spp. and Carabus spp., as well as rove beetles (Staphylinidae); Tachinus spp.. Margins dominated by wildflowers were associated with ladybirds (Coccinellidae) and weevils (Curculionidae). In 2002, grassy margins were associated with ground beetles, Bembidion spp. and click beetles (Elateridae). Thirty field boundary lengths from six study fields on one farm were assessed for plant species cover. Invertebrates were sampled in eight pitfall traps adjacent to the field boundary.
Plant nectar flower mixture/wildflower strips
A series of three replicated, controlled studies from 2000 to 2003 in the UK (Powell et al. 2004) monitored beneficial invertebrates and aphids (Aphidoidea) in crop fields with and without wildflower margins. All three studies found some beneficial invertebrates were more abundant in fields with flower-rich margins. One study (2000-2003, four farms) found more ground beetles (Carabidae) and Pterostichus spp. and smaller aphid populations in fields with flower-rich margins than those with tussocky grass margins, or no margins. Numbers of adult aphid-eating hoverflies were similar in winter wheat fields with and without flower margins. In the same study in 2003 (four new locations with different crop types, same study as (Powell et al. 2003)) more aphids were parasitized and there were more parasitoids in a broccoli field with a flower-rich margin than in one with control (no field margins) and areas treated with a pheromone to enhance numbers of aphid-specific parasitoid wasps (Aphidiinae). In a 2002 study on four fields, more predatory invertebrates were found next to flower-rich set-aside strips than conventional field margins in mid-July (margins 24 m wide, including phacelia Phacelia tanacetifolia, sunflowers Helianthus spp., yellow sweet clover Melilotus officinalis). More cereal aphids but fewer rove beetles (Staphylinidae) were found next to flower-rich margins in wheat or pea fields respectively. Cereal aphid numbers were unaffected by field margins. The study was continued in four winter wheat and four pea fields. It found abundance of ground beetles, Harpalus spp., field overwintering and predatory invertebrates and ground beetle species richness was higher in pea fields with flower-rich set-aside strips than fields with control margins. However numbers of field overwintering invertebrates, predatory invertebrates, rove beetles, Pterostichus spp. and rove beetle species richness were lower in wheat fields with wildflower strips. Pea aphid Acyrthosiphon pisum abundance did not differ between pea fields with or without set-aside strips. Numbers of some hoverflies or aphids were unaffected by the presence of sown margins in all studies. Invertebrates were sampled using a range of methods, including suction-sampling, pan traps and pitfall traps. The 2000-2003 study consisted of four transects in three winter wheat fields: one field with wildflower-rich margin, one with tussocky grass margin, one with neither.