Individual study: Biological control
Dent D. (2000) Biological control. Pages 180-234 in: Insect pest management. CABI Publishing, Wallingford, UK.
This study is summarised as evidence for the intervention(s) shown on the right. The icon shows which synopsis it is relevant to.
Create beetle banks
A 2000 literature review (Dent 2000) found two studies from the UK and USA showing natural enemy populations were larger in beetle banks than the surrounding crop (Rodenhouse et al. 1992) or other field margin habitats (Thomas et al. 1991, the same study as above). There were fewer potato leafhoppers Empoasca fabae in fields with grass corridors (Rodenhouse et al. 1992). One study from 1988 (and updated in 1994) calculated that establishing a beetle bank in a 20 ha field could save £660 (US$1,090) if an aphid-induced yield loss of 5% was prevented and £300/year (US$495) in pesticide and labour costs if natural enemy populations kept aphid (Aphididae) numbers below a spray threshold (Wratten 1988, Wratten & van Emden 1995). Economic costs of establishing a beetle bank in a 20 ha field were approximately £85 (US$140) in year one based on: labour cost (1-2 days), yield loss from land taken out of production (assuming an average yield of 6 t/ha at £110/t, or US$180/t) and cost of grass seed (£5 or US$8). Gross yield lost in subsequent years because of the beetle bank taking up production land was calculated at £30 (US$50).
Rodenhouse N.L., Barrett G.W., Zimmerman D.M. & Kemp J.C. (1992) Effects of uncultivated corridors on arthropod abundances and crop yields in soybean agroecosystems. Agriculture, Ecosystems and Environment, 38, 179-191
Wratten S.D. (1988) The role of field boundaries as reservoirs of beneficial insects. Pages 144-150 in: A.J. Burn, T.H. Coaker & P.C. Jepson (eds.) Environmental Management in Agriculture: European Perspectives. EEC/Pinter Publishers, London.
Wratten S.D. & van Emden H.F. (1995) Habitat management for enhanced activity of natural enemies of pests. Pages 117-145 in: D.M. Glen, M.P. Greaves & H.M. Anderson (eds.) Proceedings of the 13th Long Ashton Symposium, England: Ecology and Integrated Farming Systems. John Wiley & Sons, London.