Sustainable Control of Crop Pests Section 1. Biological control of crop pests through the manipulation of the farm ecological infrastructure and modification of the tillage regime The scope of this report focuses on identifying both novel and age-old techniques used to sustainably manage the pests of key crops within the UK. Five crops have been selected, based on the proportion of our land area, as of June 2014 (DEFRA, 2015). • Cereals (3179 thousand ha) or (3362 thousand ha including maize) • Oilseed rape (675 thousand ha) • Potatoes (141 thousand ha) • Peas & field beans (139 thousand ha) • Vegetables grown outdoors (116 thousand ha) It should be noted that there is a much greater weighting toward cereal and oilseed crops than in other crops, due to the proportionate size of the areas cultivated. It is also essential to remember that there is no one-size-fits-all approach to biological control of crop pests. In light of this, a combination of approaches may be required, so please bear in mind that techniques used to control some pests may also be relevant to pests of other crops, yet this still may not be suitable for all farming systems. GWCT are thankful for the support from The Frank Parkinson Agricultural Trust, Agri-Leadership Programme Award. 1 Sustainable Control of Crop Pests Contents SECTION 1. Cereals: biological control strategies ........................................................................... 8 1.1. Aphids (Aphididae spp.) .................................................................................................... 8 1.1.1. Introduction & life history................................................................................................... 8 1.1.2. Damage/presence ............................................................................................................... 8 1.1.3. Pest thresholds.................................................................................................................... 8 1.1.4. Potential for control............................................................................................................ 9 1.1.4.1. Chemical control ......................................................................................................... 9 1.1.4.2. Biological control ........................................................................................................ 9 1.1.4.3. Cultural control ......................................................................................................... 13 1.1.5. Outlook.............................................................................................................................. 14 1.2. Wireworms (Agriotes spp.).............................................................................................. 15 1.2.1. Introduction & life history................................................................................................. 15 1.2.2. Damage/presence ............................................................................................................. 15 1.2.3. Pest thresholds.................................................................................................................. 15 1.2.4. Potential for control.......................................................................................................... 17 1.2.4.1. Chemical control ....................................................................................................... 17 1.2.4.2. Biological control ...................................................................................................... 17 1.2.4.3. Cultural control ......................................................................................................... 18 1.2.5. Outlook.............................................................................................................................. 23 1.3. Orange wheat blossom midge (Sitodiplosis mosellana) .................................................... 24 1.3.1. Introduction & life history................................................................................................. 24 1.3.2. Damage/presence ............................................................................................................. 24 1.3.3. Pest thresholds.................................................................................................................. 24 1.3.4. Potential for control.......................................................................................................... 25 1.3.4.1. Chemical control ....................................................................................................... 25 1.3.4.2. Biological control ...................................................................................................... 25 1.3.4.3. Cultural control ......................................................................................................... 25 1.3.5. Outlook.............................................................................................................................. 26 1.4. Wheat bulb fly (Delia coarctata)...................................................................................... 27 1.4.1. Introduction & life history................................................................................................. 27 1.4.2. Damage/presence ............................................................................................................. 27 1.4.3. Pest thresholds.................................................................................................................. 27 1.4.4. Potential for control.......................................................................................................... 27 1.4.4.1. Biological control ...................................................................................................... 27 1.4.4.2. Cultural control ......................................................................................................... 28 2 Sustainable Control of Crop Pests 1.4.5. Outlook.............................................................................................................................. 28 1.5. Frit fly (Oscinella frit) ...................................................................................................... 29 1.5.1. Introduction & life history................................................................................................. 29 1.5.2. Damage/presence ............................................................................................................. 29 1.5.3. Pest thresholds.................................................................................................................. 29 1.5.4. Potential for control.......................................................................................................... 29 1.5.4.1. Chemical control ....................................................................................................... 29 1.5.4.2. Biological control ...................................................................................................... 29 1.5.4.3. Cultural control ......................................................................................................... 30 1.5.5. Outlook.............................................................................................................................. 31 1.6. Leatherjackets (Tipula spp.)............................................................................................. 32 1.6.1. Introduction & life history................................................................................................. 32 1.6.2. Damage/presence ............................................................................................................. 32 1.6.3. Pest thresholds.................................................................................................................. 32 1.6.4. Potential for control.......................................................................................................... 32 1.6.4.1. Chemical control ....................................................................................................... 32 1.6.4.2. Biological control ...................................................................................................... 32 1.6.4.3. Cultural control ......................................................................................................... 33 1.6.5. Outlook.............................................................................................................................. 34 1.7. Minor pests within cereals .............................................................................................. 34 1.7.1. Gout fly (Chlorops pumilionis)........................................................................................... 34 SECTION 2. Oilseed rape and other brassicas: biological control strategies .................................. 35 2.1. Slugs............................................................................................................................... 35 2.1.1. Introduction & life history................................................................................................. 35 2.1.2. Damage/presence ............................................................................................................. 36 2.1.3. Pest thresholds.................................................................................................................