Yellow wheat blossommidge 3 5 4Frit fly 91 (2) 6 3 5 4 2 4Gout fly 2 4 2 2 2 2 2Yellow Cereal Fly 0Wheat bulb fly 2 4 2 2 2 2 2Cereal leaf beetle 3Cereal ground beetle ?Wireworm ?Cereal stem sawfly 2 4Leatherjackets 2Slugs 10-20Oilseed rape <strong>pests</strong>Cabbage aphid 3 6 4 5 4 3 2 E, L, F 1Peach-potato aphid 2 6 4 5 4 3 2 U 1Brassica pod midge >20 (2) 4 & 5 4 5 to 6 4 3 4 1Cabbage root fly 2Cabbage stem flea beetle 8 (1) 4 4 5 4 3 4 1Cabbage flea beetle 4Rape winter stem weevil 4 (2)Seed weevil >20 (3) 4 4 6 3 3 1Cabbage stem weevil 6 (1) 4 4 6 4 3 5 1Rape stem weevil 3 (1)Pollen beetle 9 (3) 3, 4 or 6 4 6 4 4 5 3Turnip sawfly 2Slugs 10-2039
<strong>and</strong> further work to examine <strong>their</strong> diet is planned. Their abundance <strong>and</strong> distribution may be manipulatedbecause they utilise floral resources, however, because they on the whole are generalist predators suchdiverse habitats that provide an abundance <strong>of</strong> prey may equally retain them. Relatively little is known aboutthe predatory Heteroptera inhabiting arable fields (Moreby, pers. comm.). Their diversity is lower than forsome <strong>of</strong> the other Orders <strong>and</strong> they are usually most abundant at field edges, consequently they may be lesseffective as biocontrol agents. However, most studies <strong>of</strong> invertebrates have been conducted at field edges orinvolve the use <strong>of</strong> pitfall traps <strong>and</strong> consequently the distribution <strong>of</strong> predatory Heteroptera within fields ispoorly understood. Only one species <strong>of</strong> Neuroptera is considered to be important in arable fields <strong>and</strong> thisfeeds predominantly on aphids. It has been shown to respond to chemical cues <strong>and</strong> is a potential c<strong>and</strong>idatefor manipulation using semiochemicals.The ability <strong>of</strong> predators to withst<strong>and</strong> starvation is another key attribute that improves <strong>their</strong> survival <strong>and</strong>effectiveness as biocontrol agents. Indeed, spiders have become physiologically adapted to survive longperiods without food (Wise, 1993) <strong>and</strong> carabids have also been shown to be food limited within cereal fields(Bilde & T<strong>of</strong>t, 1998).The parasitoids <strong>of</strong> the more serious <strong>pests</strong> have been well studied <strong>and</strong> <strong>their</strong> potential to control the pestquantified. Parasitoids are able to find <strong>their</strong> hosts wherever they may be within a field <strong>and</strong> consequently <strong>their</strong>distribution is linked to that <strong>of</strong> <strong>their</strong> host, although they may make use <strong>of</strong> floral resources along fieldboundaries. Of the cereal <strong>pests</strong>, the parasitoids <strong>of</strong> cereal aphids have been the most intensively studied <strong>and</strong><strong>their</strong> manipulation using semiochemicals is a real possibility, as demonstrated in the 3D Farming project(Powell et al., 2004). Further research on <strong>their</strong> manipulation using semiochemicals is underway or has beenrecently completed (Appendix 4, Project nos. 5, 18, 23, 24, 31). Enhancement <strong>of</strong> other parasitoids isrecommended through the judicious use <strong>of</strong> insecticides using treatment thresholds <strong>and</strong> cultural measures.Their manipulation using habitat manipulation for arable pest control has seldom been explored. In theMASTER project (Appendix 4, Project no. 39) ways to conserve <strong>and</strong> enhance the 11 key parasitoids <strong>of</strong>oilseed rape <strong>pests</strong> (<strong>and</strong> other <strong>natural</strong> <strong>enemies</strong>) are being explored in order to construct, develop, evaluate <strong>and</strong>promote an IPM system (Williams et al., 2005). Techniques include the manipulation <strong>of</strong> row spacings, seedrates, seed mixes <strong>and</strong> insecticide inputs alongside different cultivation methods.4.3 Long-term changes in pest <strong>natural</strong> enemy populationsThe only long-term monitoring <strong>of</strong> arable pest <strong>natural</strong> <strong>enemies</strong> is <strong>of</strong> those taxa collected by the GameConservancy Trust in the Sussex study. The abundance <strong>of</strong> insects <strong>and</strong> spiders is measured in approximatelyone hundred cereal fields during the third week in June each year using a Dvac suction sampler. Samplingstarted in 1970. The study area is comprised <strong>of</strong> five farms, <strong>of</strong> which four are now primarily all arable <strong>and</strong> oneremains as a mixed farm. The data from the study for the period 1970-2005 was analysed recently for TheLeverhulme Trust (Potts, Ewald <strong>and</strong> Moreby, 2006). Of the <strong>natural</strong> <strong>enemies</strong> the trends <strong>of</strong> the following40
- Page 1 and 2: Research Review No. 64June 2007Pric
- Page 3 and 4: 4.4 Manipulation of natural enemies
- Page 5 and 6: AbstractPressure to reduce insectic
- Page 7 and 8: 1. IntroductionInsect pest of cerea
- Page 10 and 11: higher in ‘new’ areas.Rape wint
- Page 12 and 13: Potential damage can be caused by t
- Page 14 and 15: loss than the winter generation whi
- Page 16 and 17: 2.12 ‘Wessex’ flea beetle (Psyl
- Page 18 and 19: Cabbage stem flea beetles hatch at
- Page 20 and 21: 4. Review of cereal pest natural en
- Page 23 and 24: midgeContarinia tritici Larva/Pupa
- Page 25 and 26: Cereal ground beetle No infoZabrus
- Page 27 and 28: Myzus persicae Coleoptera Cantharid
- Page 29 and 30: Delia radicum Egg/Larva/Pupa Many C
- Page 31 and 32: Diospilus oleraceus Hymenoptera Bra
- Page 33 and 34: (Biocontrol of Oilseed Rape Insect
- Page 35 and 36: Dolichopodidae (La)Damp areas/Soil/
- Page 37 and 38: 2002). Nevertheless, there have bee
- Page 39: Therevidae (Stiletto flies) 2 1 2 2
- Page 43 and 44: ate of repopulation depends on many
- Page 45 and 46: Table 6. Resources provided for nat
- Page 47 and 48: (Crateagus mongyna) supported 209 i
- Page 49 and 50: densities varied enormously between
- Page 51 and 52: in prep). Likewise other studies of
- Page 53 and 54: compared to other cereal crops (Hol
- Page 55 and 56: Wildbird cover can develop a rich u
- Page 57 and 58: females select species with appropr
- Page 59 and 60: Skylark plots were found to support
- Page 61 and 62: Carabid abundance was higher 8m int
- Page 63 and 64: 6. Conclusions on potential of Envi
- Page 65 and 66: Where no noxious weeds or volunteer
- Page 67 and 68: conducted in isolation because of t
- Page 69 and 70: 8. ReferencesAdis, J. (1979) Proble
- Page 71 and 72: Chambers, R. J., Sunderland, K. D.,
- Page 73 and 74: Frampton, G. K., Cilgi, T., Fry, G.
- Page 75 and 76: Holland, J. M., Perry, J. N. & Wind
- Page 77 and 78: Meek, B., Loxton, D., Sparks, T., P
- Page 79 and 80: Sotherton, N. W. (1985) The distrib
- Page 81 and 82: oilseed rape across Europe. The BCP
- Page 83 and 84: 2001 More late August drilled winte
- Page 85 and 86: 1998 August drillings emerged rapid
- Page 87 and 88: Oilseed rapeHarvest Review - pest h
- Page 89 and 90: favoured rapid crop development and
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Harvest year 2005. Substantial reco
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Harvest years 2004 and 2003. Limite
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Harvest year 2005. Low numbers of o
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Harvest year 2006. Moderate to high
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Harvest year 2007 (to date). Increa
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Appendix 4. Current and recent comp
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LINK funded projects - current25 Ma
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Appendix 5. List of British researc
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