Establishing biofumigation as a sustainable pesticide replacement for control of soil-borne pests and pathogens in potato and horticultural crops.

Lead Research Organisation: University of Leeds
Department Name: Ctr for Plant Sciences

Abstract

Our research is designed to help UK farmers control soil pests which damage crop production cheaply and effectively at the same time as reducing dependence on conventional pesticides which might harm the environment. The most damaging of these soil pests are microscopic nematode worms. There are different species of nematodes: some attack potato plants whilst others can infect a range of plants, including carrots and soft fruit. The most prevalent economically important species of nematode, and so the one that has the highest economic impact on UK farmers, infects the roots of potato plants and is consequently termed potato cyst nematode (PCN). There are disproportional impacts on our potato industry because of a higher incidence of PCN in the UK than in most of Europe. EU legislation has resulted in the recent loss of two major chemicals used to control nematode pests, termed nematicides, in response to the environmental concerns their use raised and plans to amend the legislation regulating pesticide use still further are likely to remove the three remaining nematicides, possibly quite suddenly. This is causing major concern to the British potato industry because it is doubtful if new pesticides, which are effective but also meet appropriate environmental safety standards, can be developed in time to replace the pesticides being phased out.
One alternative control method that could be adopted in the limited timeframe available to UK potato growers is a strategy known as biofumigation, which suppresses pests by incorporating mustards and other types of plants into soil. Potato Council Ltd (which safeguards the interests of the UK potato growing industry) and the Horticultural Development Company (which promotes the UK horticultural sector), in conjunction with potato businesses, have now committed to support research to understand exactly how biofumigation works and how the potential of this technique can be exploited most effectively under field conditions. Our preliminary work has characterised a number of different plant species that produce natural chemicals which detrimentally affect PCN. We have shown that biofumigation can be used to stop the eggs of PCN from hatching into worms which subsequently attack potato plants.
We have identified different types of mustard plant that could be used in biofumigation because of the range of natural anti-nematode chemicals they produce. However, inconsistencies in the effectiveness of these plants and a lack of detailed data on how best to deploy biofumigation under a range of agronomic situations prevent the widespread uptake of this sustainable pest control technique. This project will address this knowledge gap by elucidating the fundamental biochemical and metabolic processes underpinning effective biofumigation. It will characterise the profiles of the active chemical compounds, called glucosinolates, of different biofumigant mustards and determine how these vary with plant development stage and environmental factors. It will identify novel active compounds potentially effective against pests but not, as yet, evaluated in biofumigant field trials. We will analyse the effects of biofumigant plants on a range of pests both in glasshouse studies and in multiple field trials. We will use a novel plant growth technique that makes soil appear transparent allowing us to observe the effects of biofumigation on some of the nematode species for the first time. It must be shown that biofumigation does not adversely affect UK soils before the approach can be endorsed by the Potato Council, DEFRA, EU or certifiers of organic produce. We will therefore analyse the impact of biofumigant crops on beneficial organisms in the soil when deployed in the field. Outputs of the research will allow optimal deployment of biofumigation strategies for maximum efficiency over a range of field conditions, providing a sustainable pest control option for both conventional and organic farmers.

Technical Summary

Soil-borne pests, including nematode and fungal species, are major constraints to crop production. Nematode control in agricultural crops is expensive, often ineffective and reliant on synthetic chemicals. Many chemicals have been withdrawn, with the remaining three likely to be withdrawn gradually or abruptly due to EU legislation. Chemical control of soil-borne fungi is also problematic. New approaches that have broad efficacy and are suitable for use on a wide range of crops are urgently required. Biofumigation involves the incorporation into soil of brassicaceous plants, which produce a range of secondary metabolites, including glucosinolates, which are able to control pests. However, inconsistencies in efficacy and a lack of detailed data on optimal deployment under a range of agronomic situations prevent the effective, widespread uptake of this pest control technique. This programme will address this knowledge gap by elucidating the fundamental biochemical and metabolic processes underpinning effective biofumigation strategies. It will characterise glucosinolate profiles of different biofumigant brassicas and determine how these vary with plant development stage and environmental factors. It will identify novel secondary metabolites potentially effective against pests but not, as yet, evaluated in biofumigant field trials. The effects of biofumigant plants on a range of pests both in glasshouse studies and in multiple field trials will be determined. We will use a novel plant growth system that allows visualisation of plant-feeding nematode species for which there is little information regarding the effects of biofumigation. In addition we will evaluate the impact of biofumigation on the non-target below-ground fauna. Outputs of the research will allow optimal deployment of biofumigation strategies for maximum efficacy over a range of field conditions, providing a sustainable pest control option for both conventional and organic crop production.

Planned Impact

A: Beneficiaries from this research
Improving the environmental sustainability of agriculture whilst increasing food production is a key aim of the Government's food security agenda; finding more environmentally acceptable methods of pest control will make an important contribution to this objective. Our research is designed to help UK farmers control key soil pests more cheaply and effectively at the same time as reducing dependence on conventional pesticides.
A1: Commercial private sector. (i) Suppliers of planting material to the UK potato industry: The Potato Council estimates the UK potato industry is worth £3 billion p.a. Our proposed research supports suppliers of inputs for potato cropping: It will provide planting material of biofumigant crops with assured efficacy to all growers at less cost than the alternative of chemical control. (ii) UK potato growers: They urgently need new, more economic approaches to control Globodera pallida. The pesticides used to control this nematode are the largest variable cost of the growers who use them and currently 23% of the UK potato acreage is treated each year. This is unsustainable given EU plans to phase out these pesticides. Our novel biofumigation approach is cheap, effective and compatible with both conventional and organic production. (iii) Supermarkets: Major supermarkets such as Waitrose, see value in removing even the theoretical risk of pesticide residues from the potatoes they sell. Our outputs will support that policy.
A2: Policy-makers. DEFRA and SEERAD must implement EU's amendment to Directive 91/414/EEC that will reduce use of crop protection chemicals in agriculture. The Directive involves the withdrawal of pesticides from the UK market, a challenge for UK potato and horticultural production unless effective alternatives for control of G. pallida and other nematode species can be adopted in the timescale that the Directive sets. For the EU, our work would support practical implementation of their poicy to replace certain pesticides. DEFRA and SEERAD must also support an EU Directive specifically aimed at potato cyst nematodes (2007/33/EC).
A3: General Public. Most of the UK population consumes the crops, ranging from potatoes to soft fruit, that are attacked by nematodes and fungi so will benefit from produce that is produced in as cost-effective and environmentally sustainable way as possible..

B: Nature of benefits from this research
B1: Benefits for UK economic competitiveness. The increasing prevalence of G. pallida has contributed to a decline in the UK potato crop of 12% between 1999 and 2012. This is a larger fall than for other major EU producers that lack this pest. Our work would help overcome the problem of PCN control that faces many UK producers.
B2: Increasing the effectiveness of public services and policy. It is relevant for those who seek to implement change in policies, such as the amendment to Directive 91/414/EEC and implementation of 2007/33/EC, to have alternative practical procedures growers can adopt.
B3: Enhancing quality of life, health and creative output. Reducing the need for pesticides carries a benefit for both UK biodiversity and the consumer. A distinctive feature of this work is the short lead-in time it requires before practical benefits can be obtained. A recent Royal Society report identified a clear need for training more researchers in agricultural sciences, so the postdoctoral scientists in this project will be trained in an area of considerable importance and recent neglect.

C: Ensuring benefits from this research reach users
C1: Communication and engagement plans. This project involves the Potato Council Ltd and Horticultural Development Company. Another eight partners from across the potato and horticultural industries are also involved, which will help ensure the outputs from the project reach the end-users as described in the 'Pathways to Impact' section of this application.
 
Description Soil-borne pests and pathogens are major constraints to crop production. Nematode control in agricultural crops is expensive, often ineffective and reliant on synthetic chemicals. Chemical control of soil-borne fungi is also problematic. New approaches with broad efficacy, which are suitable for use on a wide range of crops, are urgently required. Biofumigation involves incorporation into soil of glucosinolate-containing brassica plants for control of pests. Glucosinolates are hydrolysed by microbial and plant myrosinase enzymes to yield bioactive products, particularly isothiocyanates, when plant tissue is damaged. However, inconsistent efficacy and a lack of detailed data on optimal deployment of biofumigation under a range of agronomic situations prevent the widespread uptake of this technique. Our project has addressed this knowledge gap by elucidating factors underpinning effective biofumigation. We have characterised how glucosinolate profiles of different biofumigant plants vary with developmental stage and with both agronomic and environmental factors. We have identified other secondary metabolites produced by some brassica plants that have toxicity towards nematodes. The effects of biofumigation on a range of pests and pathogens have been determined in glasshouse, polytunnel and field trials. We have developed a novel plant growth system to visualise a group of plant-feeding nematodes for which there is little information regarding the effects of biofumigation. In addition, in ongoing work, we are evaluating the impact of biofumigation on non-target below-ground fauna.
A number of key findings to date will either direct future research or influence biofumigation best practice.
• Seeding density has little effect on isothiocyanate-release potential of biofumigant crops at incorporation.
• Optimum incorporation time for a biofumigant crop is when plants are flowering.
• The major biofumigant compound is lost rapidly from soil after mustard incorporation, but other, less well-studied chemicals increase in soil over time and may contribute to pest/pathogen toxic effects.
• Volatile halide compounds are produced by roots of growing brassicas and are lethal to potato cyst nematode juveniles at very low doses.
• Standard glucosinolate extraction techniques were improved to provide a new method that gives cheaper, quicker and more accurate results.
• An imaging and detection system has been developed to monitor behaviour of nematodes in transparent soil microcosms. This can be used to assess effects of biofumigant chemicals
• Two soil-borne fungal pathogens, Rhizoctonia solani and Verticillium dahliae are differentially sensitive to a range of isothiocyanates, but symptoms of R. solani on potato were not reduced by biofumigation with a mustard in a glasshouse trial.
• There is a significant decline in viability of potato cyst nematodes during growth of a mustard crop, prior to incorporation. This outcome differs with soil type, whilst efficacy of biofumigation after incorporation is affected by both soil type and soil moisture.
Exploitation Route Widespread grower uptake of biofumigation is currently limited by a lack of data on the factors affecting its consistent efficacy. The combined findings from this project will allow the formulation of optimal deployment strategies to ensure that biofumigation delivers maximum efficacy for growers. The results and their implications for agronomic practice in the UK are being incorporated into "Best Practice" information on the use of biofumigation to be disseminated to growers and agronomists by AHDB.
We have defined the mustard and radish biofumigant cultivars of choice based on their biofumigation potential and clarified the optimum growth stage for incorporation.
Importantly, we found that biofumigant seeding rates have no significant impact on biofumigation potential. This new knowledge suggests that grower costs can be minimised by reducing seeding rate without negatively affecting biofumigation potential.
We found that the main biofumigation compound is lost from soil within 24 hours after incorporation. This is important knowledge both for informing the most effective incorporation techniques and when designing realistic in vitro exposure assays with pests and pathogens.
Sectors Agriculture, Food and Drink,Environment

 
Description The research outputs coming from the HAPI project were used in the first ARTIS (Agri-Tech Register and Training for Innovation and Skills) course on use of biofumigants in the rotation, delivered by Dr Matt Back at Harper Adams University in January 2016 and again in March. This practical course has been devised to teach crop managers, agronomists and industry specialists looking to gain the skills necessary to optimise biofumigant success. The results and their implications for agronomic practice in the UK are being incorporated into "Best Practice" information on the use of biofumigation to be disseminated to growers and agronomists by AHDB.
First Year Of Impact 2016
Sector Agriculture, Food and Drink
Impact Types Societal,Economic

 
Description SARIC Sustainable Agriculture and Innovation
Amount £167,601 (GBP)
Funding ID NE/P00797X/1 
Organisation Natural Environment Research Council 
Sector Public
Country United Kingdom
Start 07/2017 
End 02/2019
 
Description AHDB Biofumigation 
Organisation Harper Adams University
Country United Kingdom 
Sector Academic/University 
PI Contribution Sharing of data from field trials, glasshouse trials and laboratory studies. Access to facilities and expertise for sample analysis. Hosting meetings for sharing of data and experiences.
Collaborator Contribution Sharing of data from field trials, access to field trial sites for sampling. Sharing of expertise and best agronomic practice for biofumigation.
Impact The outputs of this collaboration are still to be realised
Start Year 2015
 
Description AHDB Agronomists Conference 2019 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Industry/Business
Results and Impact AHDB invited Prof Urwin to attend the Agronomists Conference 2018 held at the Kettering Conference Centre in December 2018. He gave a presentation to a mixed audience of growers, agronomists and industry representatives focusing mainly on the results to date from our SARIC project. This involved our research into the decline rates of potato cyst nematode in the field and how these are influenced by environmental and agronomic factors. The talk also included effects of biofumigation - the focus of our HAPI project. The presentations were followed by a panel question and answer session, with questions from the audience and discussion amongst the panel of speakers.
Year(s) Of Engagement Activity 2018
URL https://cereals.ahdb.org.uk/media/1459689/Agronomists-Conference-2018-Master-Deck-Day-1-Final.pdf
 
Description BP2015 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Industry/Business
Results and Impact Gave presentation of the group's research to growers/industry representatives at The Potato Industry Event BP2015 followed by question and answer session. This was part of the "Research and Innovation for the Future" session to inform the industry of the latest advances and likely future developments in potato research. The presentation stimulated questions from the audience and further discussion.
Year(s) Of Engagement Activity 2015
URL http://www.bp2015.co.uk/seminars.html
 
Description BP2017 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Industry/Business
Results and Impact Prof Urwin attended the Potato Industry Event BP2017 at the Harrogate Yorkshire Event Centre in November 2017. This event attracts those involved in growing, handling, processing and retailing the potato crop and provides an excellent engagement and dissemination platform for all the potato-related research of the group. Prof Urwin delivered an open presentation summarising the team's research related to managment of potato cyst nematode, focusing particularly on progress towards improving the AHDB PCN modelling tool. In addition, there was engagement and discussion with numerous industry members and agronomists/potato researchers that led to interest in future research directions and potential collaborations.
Year(s) Of Engagement Activity 2017
URL https://www.bp2017.co.uk/index.html
 
Description Discovery Zone 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Schools
Results and Impact The whole research group was involved in preparing and carrying out an activity-based display at the "Discovery Zone" event for local schools held at the University of Leeds. The event took place over 2 days and more than four hundred school children from Key Stages 2 and 3 engaged with the interactive exhibit "Getting to the root of the matter". We saw over 490 pupils in total - around 260 primary school children, and 230 secondary school children. Age appropriate activities and information relating to crop plants, the importance of roots and root pests and diseases were provided in small group sessions.
Year(s) Of Engagement Activity 2016,2017,2018
 
Description Foundation for Arable Research 
Form Of Engagement Activity A formal working group, expert panel or dialogue
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Members of the Foundation for Arable Research based in New Zealand visited our group at Leeds on a knowledge gathering trip to learn of our research into using biofumigation for management of soil-borne pests of potato. A presentation of our research was followed by a general discussion and exchange of knowledge and experiences.
Year(s) Of Engagement Activity 2015
 
Description Frontier Potato Group Presentation 
Form Of Engagement Activity A formal working group, expert panel or dialogue
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Professional Practitioners
Results and Impact Talk sparked questions and discussion afterwards: possibilities of commercial direction.

The audience were aware of GM technology that could provide a solution to nematode pathogens
Year(s) Of Engagement Activity 2012,2015
 
Description Potatoes in Practice 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Industry/Business
Results and Impact The work of the Research Team into optimising biofumigation for pest and pathogen control was exhibited as part of an AHDB display to farmers, agronomists, industry, scientists and policymakers at the Potatoes in Practice event, Dundee. Potatoes in Practice is the largest field-based potato event in the UK, bringing together variety trials, research and trade exhibits. The event raised awareness of our research amongst the potato industry.
Year(s) Of Engagement Activity 2015
 
Description SPot Farm West results day Jan 2018 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Industry/Business
Results and Impact Team members and collaborators attended the SPot Farm West results day at Harper Adams University to disseminate the findings of trials related to nematode control and management carried out during 2017 at the AHDB Strategic Potato Farm. Results of PCN tolerance trials that were part of the SARIC funded research to improve the PCN population advisory tool were presented to an audience of growers, agronomists and other representatives of the poato industry. Biofumigation for control of potato cyst nematodes was also discussed and trial results presented.
Year(s) Of Engagement Activity 2018
URL https://potatoes.ahdb.org.uk/publications/spot-west-results-day-presentations-2018
 
Description SPot Farm demo trials 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Professional Practitioners
Results and Impact One of the AHDB demonstration farms for showcasing best agronomic practices hosted a number of trials related to management and control of potato cyst nematodes. A nukber of Open Day events throughout the growing season were attended by growers, agronomists and industry representatives. Field talks and demonstrations informed the audience about the background and principles of biofumigation together with information about how best to optimise their use. The advice presented by onr of our project partners, Dr Andy Barker, was informed in part by our research. The Open Days also involved talks and presentations related to the PCN tolerance trial being carried out at the site as part of the SARIC project to improve the PCN advisory tool.
Year(s) Of Engagement Activity 2017
URL https://potatoes.ahdb.org.uk/events/spot-west-open-afternoon
 
Description University Open Days 
Form Of Engagement Activity Participation in an open day or visit at my research institution
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Public/other audiences
Results and Impact The work undertaken by the research team in developing nematode resistant crops was demonstrated to visitors. Visitors were engaged in discussions about the work and GM technology in general. Postgraduate students, postdocs and technicians associated with the grants all took part in either preparing or demonstrating the events.

Prospective students encouraged to apply for courses with an applied biology focus
Year(s) Of Engagement Activity 2009,2010,2011,2012,2013
 
Description Westmorland Show 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Public/other audiences
Results and Impact Prof Urwin presented the research into methods for nematode control, including biofumigation and GM crops, at the Westmorland County Show to members of the general public and the farming community. The aim was to raise awareness of fundamental research being carried out and its potential for future strategic deployment in the UK agricultural sector.
Year(s) Of Engagement Activity 2008,2015