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Increasing biopesticide use in oilseed rape crops – addressing barriers and realising opportunities

Primary Supervisor: Dr Joe Roberts, HAU

Secondary supervisor:Dr Tom Pope (HAU), Mr Simon Cooper (HAU) and Prof. James Lowenberg-DeBoer (HAU)

PhD project title: Increasing biopesticide use in oilseed rape crops – addressing barriers and realising opportunities

University of Registration: Harper Adams University

Project outline:

Project background:

In recent decades oilseed rape (OSR) has been the most profitable ‘break crop’ in many arable rotations in the UK. However, growers are now being forced to seek alternatives due to cabbage stem flea beetle (Psylliodes chrysocephala) feeding and turnip yellows virus vectoring peach-potato aphids (Myzus persicae). The increased pest pressure from these two insects in particular is largely driven by fewer available effective control measures. In OSR this has been due to the EU banning neonicotinoid pesticide use and emergence of widespread resistance to pyrethroid insecticides. A reduced ability to effectively control OSR pests has been largely responsible for the more than 50 % reduction in area sown to OSR between 2012 and 20201.

One potential replacement for neonicotinoid pesticides are crop protection products known as biopesticides, which are manufactured from natural sources2. Biopesticides targeting insect pests currently account for 20 % of all products registered for professional use in the UK, but these are almost exclusively used on high value horticultural crops and are priced accordingly (£100-£300/ha per application). The cost of biopesticides is further increased as most require repeat applications to be effective due to poor residual effects. While biopesticides can often be applied using conventional spray equipment, applications typically require large volumes of water (e.g. 1500 L/ha) to achieve adequate crop coverage. Environmental conditions during application also determine product efficacy, limiting their use to periods of dry weather or during the evening when humidity is higher and UV radiation is lower.

To date there has been comparatively little research investigating the potential of biopesticides for OSR crop pest management. Their cost, high application frequency, large water volume requirements and environmental sensitivity creates significant barriers to effective biopesticide application in OSR. This project aims to address these barriers and investigate the potential of autonomous farm equipment to improve biopesticide application and affordability for growers.


  1. Lowenberg-DeBoer, J., Pope, T. W. and Roberts, J. M. (2020) ‘The economic feasibility of autonomous equipment for biopesticide application’. International Network for Economic Research Symposium on Agri-Tech Economics for Sustainable Futures, Shropshire, UK, October 21-22.
  2. Chandler, D., Bailey, A. S., Tatchell, G. M., Davidson, G., Greaves, J., and Grant, W. P. (2011) The development, regulation and use of biopesticides for integrated pest management. Phil. Trans. R. Soc. B. 366, 1987–1998.

Project objectives:

  1. Establish baseline data for efficacy of selected botanical and microbial biopesticides against both pests under laboratory conditions
  2. Investigate interactions between frequency of application and product concentration under laboratory conditions
  3. Investigate interactions between frequency of application and product concentration in small plot experiments
  4. Investigate feasibility of ultra-low volume (ULV) application technologies, such as electrostatic sprayers, to apply botanical biopesticides. Initially under laboratory conditions but moving to small plot experiments
    1. Investigate product concentrations for efficacy and phytotoxicity
    2. Investigate frequency of application for efficacy and phytotoxicity
    3. Investigate effect of application frequency on plant volatile emissions and their role in host plant selection by pests and natural enemy recruitment
    4. Investigate interactions between product concentration and frequency of application on efficacy and phytotoxicity
  5. Complete replicated field experiments to investigate the efficacy of selected ULV application techniques for control of aphids and cabbage stem flea beetle on OSR
  6. Investigate the economics of biopesticide applications applied using ULV application technologies versus conventional systems when applied using standard or autonomous machinery

BBSRC Strategic Research Priority: Sustainable Agriculture and Food: Plant and Crop Science

      Techniques that will be undertaken during the project:

      Laboratory work

      • Biopesticide efficacy assays (lethal and sub-lethal)
      • Insect behaviour assays (olfactometry, feeding, etc.)
      • Insect culturing techniques
      • Gas chromatography-mass spectrometry (GC-MS)

      Field work

      • Biopesticide application techniques (ULV, knapsack, etc.)


      • Economic modelling

      Contact: Dr Joe Roberts, HAU