Evaluating Biofumigation as a Sustainable replacment for Pesticide Use to Control Soil Borne Pests

Lead Research Organisation: James Hutton Institute
Department Name: Cell & Molecular Sciences

Abstract

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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 Many chemicals have been withdrawn, with the remaining three likely to be withdrawn gradually or abruptly due to EU legislation.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 policy 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 nematode species 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 8 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.

Publications

10 25 50
 
Description 1) We have developed customized transparent soil microcosms in which plants and nematodes can be cultivated and imaged with a range of techniques, eg. light sheet microscopy for macro-imaging of root architecture in 3D and confocal laser scanning microscopy for imaging micro-scale plant- nematode interactions. The microcosm allows both natural plant growth and nematode movement. The system has been shown to be suitable for monitoring of both plants and nematodes over time.

2) Live nematodes are difficult to visualize as they are optically transparent and their cuticle doesn't permit stains to be absorbed. We were able to make live nematodes fluoresce through the ingestion of fluorescently stained particles; this method greatly enhances the contrast between nematodes and their surrounding environment and aids their detection.

3) A novel method for the visual detection of free living nematodes is currently being developed. This technique (dynamic speckle) uses the interference of light occurring when shone on living organisms to detect both the presence and the activity levels of soil pests such as nematodes. It therefore has great potential to be used both to assess plants overall infection levels and also to measure the efficacy of biofumigants. Using this approach it has been possible to accurately detect and count groups of nematodes that have been added to the transparent soil matrix.

4) Because of the small size of free living nematodes in relation to the plant root system it is difficult to locate them when observing a whole plant growing in transparent soil. To overcome this difficulty a technique known as Selective Plane Illumination Microscopy (SPIM) has been used to make wide visual scans of the entire root system at relatively high speed.

5) Preliminary experiments have been done in which hand-picked free-living nematodes have been treated with different concentrations of conventional nematicide in transparent soil cuvettes. Biospeckle analysis has been used to determine what concentration of nematicide results in cessation of movement of the nematodes, thus, forming the basis for a quantitative system to examine the nematicidal activity of different biofumigant chemicals.
6) Two different sample analysis methods have been combined to form a coherent sample examination system named Biospeckle Selective Plane Illumination Microscopy (BSPIM) allowing fast detection and quantitation of nematodes from soil samples. BSPIM inceases the sample signal to noise ratio by up to 60 fold. This system can differentiate between live (moving) and dead (immobile) neatodes, which is the basis for the quantitation of nematodes in each sample. BSPIM also makes it possible to differentiate between other biological material (plant roots) in the system and nematodes, therevy allowing this system to be used to study nematode feeding behavious and processes.In a different study we conducted a pot test (large 600cm3 pots containing field soil and longidorid nematodes) of biofumigant mustard plant incorporation alongside raspberry plants (Glen Ample). With respect to plant growth, root size and fruit yield there was no obvious effect of incorporation of biofumigant mustard into the soil during the raspberry growing peroid (March to October).
Exploitation Route Dynamic speckle has the potential to be used as a fast screening method of nematode activity around plants and our aim is to develop this further.
In the next part of the work we will use the imaging system described above to test the efficacy of selected biofumigant compounds. This analytical system has the potential to be applicable to many situations in which the biology of soil inhabiting organisms requires to be investigated - both from a commercial product development position and from a more fundamental, research-orientated position. We further aim to use this technique to determine the appropriate doses and mode of action of compounds with nematicidal activity. We believe this will enable the plant protection research community and industry to be able to develop new treatments and deploy them in the most sustainable way, minimising off target effects on other beneficial soil community organisms.
Sectors Agriculture, Food and Drink

URL https://plantmethods.biomedcentral.com/articles/10.1186/s13007-019-0523-8#citeas
 
Description The objectives of the work are to develop an in vitro system to visualize free living nematodes in relation to their host plant root system, and also to use this system to analyse potential nematicidal/nematistatic properties of biofumigant molecules produced in the soil from biofumigant cover crops. Our work has not been completed but we expect it will contribute to an assessment of whether/how biofumigant plants might be useful in the control of plant pathogenic free-living nematodes. If successful, this may be incorporated as part of an intergrated pest management strategy to control plant parasitic nematodes without the use of synthetic chemical treatment. During 2017 we have taken th opportunity to talk about our work and the more general aspects of biofumigant application as a potential means to control plant pathogenic (free lving) nematodes to a with range of stakeholders from the farming industry (growers, agronomists and scientists).
First Year Of Impact 2017
Sector Agriculture, Food and Drink,Communities and Social Services/Policy
Impact Types Economic

 
Title BSPIM imaging system for monitoring biological activity in transparent soils 
Description A physical platform to grow seedlings in a sterile, transparent artificial soil matrix. Additional organisms e.g. nematodes can be added to this system (or examined by themselves in the absence of a growing plant), and their behaviour or response to natural exudates/volatiles from the plant, or chemical additives or other bioactive molecules can be monitored using a novel, combined biospeckle and selective plane illumination imaging system.The transparent soil gives a matrix structure to the system which allows plant root growth to mimic natural patterns and nematode movement along soil.water boundaries to be examined. However, the system can also be assembled without the soil thereby allowing biological organisms to be examined in an aqueous background. Controlled direct addition of bioactive molecules/chemicals to the system is easy and can allow quantitative studies (for dose effect curves etc) to be done. 
Type Of Material Biological samples 
Year Produced 2017 
Provided To Others? Yes  
Impact The paper was published in December 2017 and there has not been sufficient time and opportunity to generate wider impact 
URL https://www.nature.com/articles/s41598-017-18797-7
 
Description Scientific Conference; PHOQUS 2016 - Biophotonic approaches: From molecules to living systems, UoD Dundee, 22 August 2016 - 23 August 2016 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Presentation of research progress to a scientific audience interested in biological imaging
Year(s) Of Engagement Activity 2016
 
Description Scientific Conference;The 32nd International Symposium of Nematology, University of Minho, Braga, Portugal from August 28 to September 1, 2016 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Present research findings to an audience of nematologists
Year(s) Of Engagement Activity 2016
 
Description Seminar to Certis agronomists and management 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Industry/Business
Results and Impact Knowledge transfer regarding free iving nematodes, their effects on crop yields and disease control approaches
Year(s) Of Engagement Activity 2008,2017
 
Description Talk at Hutton Research Symposium, Dundee, 22/11/2017 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Professional Practitioners
Results and Impact Presentation of research findings to assembled colleagues from the Aberdeen and Dundee sites of the James Hutton Institute
Year(s) Of Engagement Activity 2017
 
Description Talk at ISRR root workshop, title: Imaging nematodes in the rhizosphere using transparent soil, Dundee, 24/5/2017 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Dissemination of research findings to make the members of the International Society of Root Research aware of our resulsts and advances in this new technology
Year(s) Of Engagement Activity 2017
 
Description presentation to c. 100 delegates (agronomists and growers) at an industrial day organised by Agrovista Ltd, Coupar Angus, Scotland, UK, 16.2.2017 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Industry/Business
Results and Impact Dissemination of knowledge on free-living nematodes and research methods to control them
Year(s) Of Engagement Activity 2017
 
Description seminar to Soil Health KTN meeting, University of Sheffield, 14.3.2017 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Professional Practitioners
Results and Impact Knowledge transfer of information on free living nematodes and research to control them
Year(s) Of Engagement Activity 2014,2017
 
Description seminar to delegates at 11th European Conference on Precision Agriculture, Dundee 20.7.2017 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Knowledge transfer to visitors to the James Hutton Institute describing free-living nematodes, their impact on agriculture and methods of control
Year(s) Of Engagement Activity 2017