SCEPTREplus - Research for sustainable plant protection products for use in horticulture


SummaryManagement of pests, diseases and weeds is a major concern for growers of both edible and ornamental crops in the UK.  The quality of horticultural produce is paramount and even small levels of damage can lead to major losses in marketable yield.  Efforts to protect crops effectively are hampered in many instances by the limited number of control methods available on individual crops, exacerbated by the de-registration of certain pesticide products, limited development budgets in crop protection companies for new products on specialist or minor crops and incidences of resistance to some of the pesticides that are approved.   The future for pest, disease and weed control will require growers to take a true IPM approach and integrate conventional pesticides with biopesticides, cultural methods including using rotations, clean plant material, resistant varieties, pheromone technology, biocontrols and physical controls, making treatment decisions based on accurate diagnostics and pest and disease forecasts.  Crop protection companies continue to produce new actives for use on major world crops which are better targeted and have lower environmental impact and several promising fungicides and insecticides and a few herbicides are in development. However, the number of new actives that become registered for use on horticultural crops is relatively small, largely due to the small size of the market in relation to development costs. Fortunately there has been a significant increase in commercial interest and development of biopesticides and the horticulture industry will require more information on their efficacy, persistence, crop safety and how to integrate them into ‘best practice’ treatment programmes.  
Support from the industry, through AHDB, for applied research into the efficacy and use of both existing and new actives will identify new uses and determine best practice for their deployment to manage different crop/pest combinations in horticultural crops.  It may also identify new application methods or application rates that will help to fill the current gaps in control. Part of the process for new uses of pesticides will be the development of associated residue data packages to obtain Extension of Authorisation for Minor Use (EAMUs) via the AHDB funded EAMU (formerly SOLA) programme.
SCEPTREplus will help to address the issues many growers have with regard to crop protection in horticulture. The evidence from industry is clear from the strategic plans and priorities identified by the 6 panels and a number of different grower associations, with crop protection being a key priority. All levy payers are impacted to a certain degree, even those producing organically, as some of the products currently approved for use in organic systems are under threat and alternatives may have to be found; biopesticides present a particular opportunity here.
Benefits to Industry
The sector encompasses a considerable number of diverse crops with very different pressures from weeds, pests and pathogens (including plant viruses), together with more niche challenges such as growth regulation.  Each will present a different economic case.  This depends not only on the amount of crop lost but also on the cost to the company of substituting UK produce with imported product to maintain supply (e.g. importing radish from Holland to replace programmed UK crops that have been lost due to cabbage root fly damage).  Whilst cases have not been worked for every crop, there are some worked examples from the reports which considered the impact of the loss of pesticides as part of the EU review process.  
Firstly there are examples from the study by Wynn (2010) which indicated that under current production methods and available treatments, broad-leaved and grass weeds caused the largest losses in potential yield and quality with an industry value of about £110 million per year (across all crops), with strawberries being the crop most severely affected by weeds (although this is less of an issue now due to the move to tunnel production). Botrytis is the second greatest cause of losses, worth nearly £53 million, mainly affecting strawberries (£33 million) but also impacting on onions, lettuce, raspberries, tomatoes, hardy nursery stock and ornamentals. Weevils are also a problem, causing almost £52 million worth of losses across all sectors, with strawberries (due in part to the high value of the industry) again seeing some of the highest losses (£44 million).  Vine weevil is also causing high losses in hardy nursery stock (estimated at £24 million) (J. Bennison, Pers. Comm. HNS 195). 
Wynn (2010) suggested that in untreated situations, the lack of herbicide control of weeds would drastically increase costs as a result of increased requirements for hand weeding. Weed populations would gradually build up over time and could result in almost complete crop losses as a result of competition decreasing yield, contamination with seeds affecting marketability and difficulties in harvesting. Overall the cost to the industry (across all 15 crops considered) of not using herbicides could exceed £1 billion. If left untreated, pests could have a damaging effect across all crops. Losses from aphids in the absence of pesticides were estimated at £306 million, with lettuce and hardy nursery stock particularly badly affected. It was estimated that fly pests could cost the industry £216 million with the largest losses from cabbage root fly on brassicas (£145 million) followed by carrot fly on carrots (£25.6 million). Foliar diseases could cause significant losses across all crops with botrytis and downy mildew having the largest effects (£192 million and £134 million respectively).
A more recent report for the NFU by Andersons (2014) conducted an analysis of the impact of the loss of active substances that have been deemed to be at a ‘high’ risk of being lost.  This included 10 insecticides, 12 fungicides and 16 herbicides.  They concluded that, for outdoor vegetables, up to 100% of the cropped area would be affected, that yield losses would be in the order of 25-50% and cropped areas would decline by 40-50%.  Impacts on fruit yield might be less but cropped areas might decline by 30%.  In addition, the reduction in product quality is likely to lead to a drop in prices to growers since it is unlikely that retailers (consumers) will be prepared to pay an equivalent amount for a poorer quality product as illustrated by the marketing of “ugly” fruit and veg products. The increased volumes of poor quality produce may also create supply/demand problems for the wholesale and food processing sectors further depressing prices for all growers.
More recently still, an AHDB Workshop on the impact of the 2016 invasion of diamond-back moth on losses to brassica crops indicated that for Brussels sprout crops up to 100% of the crop area was affected and there were up to 40% yield losses in individual crops; for swede up to 100% of the crop area was affected with up to 15% yield losses; and for cabbage up to 80% of the crop area was affected and there were up to 10% yield losses.  This was a situation where control was impacted by insecticide resistance to pyrethroids and where cyazypyr, a new active, trialled in SCEPTRE and recently approved, provided a level of control of diamond-back moth where used as a drench (to control cabbage root fly) and additional control of diamond-back moth as a foliar spray (through an emergency EAMU supported by AHDB).  
The relatively recent arrival of Drosophila suzukii in the UK highlights the actual and potential impact of ‘new’ pests, pathogens and weeds. Economic costs of D. suzukii infestation can be considerable. Kanzawa in 1939 describes losses to cherry crops of up to 75%. In 2008, D. suzukii caused an estimated loss of $511 million to the fruit industry (Bolda et al., 2010), whilst in 2011 losses of cherries of up to 90% to 100% were reported in France and Spain, and a French government hearing quoted a loss of 5,000 Euros per farm for strawberry growers in the Dordogne in 2011 (Sénat 2012).
A Innovate UK-funded project ‘Post-harvest management of plums and cherries to minimise waste’ has the main objective of increasing the profitability of UK cherries by short-term storage to extend the marketing period with potential for exports with the increase in cherry production in particular of late season cultivars in the UK. However, storage has been limited by losses due to fungal rots, especially brown rot (Monilinia spp), Botrytis and Penicillium. Most of this is from infection in the orchard which is not well controlled by current fungicides. So finding better products to control rots would give the opportunity to improve profitability of the expanding cherry production.
Project code:
CP 165
01 April 2017 - 31 March 2021
AHDB Horticulture
AHDB sector cost:
Project leader:


About this project

AimThe aim of the project is to deliver applied research on high priority pest, disease and weed problems in fresh produce and ornamental crops in order to identify effective treatments, support approval of new products and devise and develop IPM programmes.
Objective:  The core objectives of the project are to:
1. Identify key crop protection priorities in horticultural production in the UK to fill pesticide gaps and reduce overall use of synthetic pesticides. 
2. Identify current and pre-commercial pesticides and biopesticides and assess their potential for use on key crop protection priorities in horticultural production in the UK to fill pesticide gaps and reduce overall use of synthetic pesticides. 
3. For disease and pest problems; Design and deliver pesticide and biopesticide efficacy tests on key crop protection priorities (including seed treatments and use in storage situations) in order to identify effective and crop-safe products for potential use in sustainable disease and pest IPM solutions 
4. For disease and pest problems; Design, test and feed into other sustainable IPM programmes that incorporate pesticides and biopesticides identified in this project to fill gaps in control measures and reduce the use of synthetic pesticides 
5. For weed problems; Design and deliver herbicide screening tests with emphasis on non-target crop tolerance, and potentially including residue studies where relevant. 
6. For weed problems; Design and test systems to reduce herbicide usage by more targeted application and/or other methods, and integrate these with current commercial practice.
7. Test novel non-chemical methods for weed control 
8. For any suitable candidates emerging from the objectives 1-6 above, conduct where necessary residue trials for MRL and support other regulatory data generated projects if this is considered a priority by industry representatives and AHDB. EAMU applications for suitable candidates will be carried out by AHDB with assistance from the Consortium and Researchers in terms of producing ‘cases for need’.  
9. Develop clear management and application guidelines and messages (with manufacturers) to optimise use of biopesticides, linking with other biopesticides programmes, such as AMBER (Application and Management of Biopesticides for Efficacy and Reliability). 
10. Communicate with stakeholders and disseminate information.