Development of a PCN population advisory tool that provides robust advice and management

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

Abstract

Potatoes are consumed as part of approximately 10.14 billion meals made at home each year in the UK, which is an average of three/four meals a week for each member of the population (AHDB, 2015). The home-grown supply of retail potatoes accounts for 87% of the market. AHDB Potatoes estimates the UK potato production together with subsequent processing and added value has an annual value of £4.5 - 5.5 billion.
The potato cyst nematodes (PCN) Globodera rostochiensis and G. pallida are important soil pests that cause major economic losses to potato growers. G. pallida is the most prevalent species in the UK and its control is the most problematic. A lack of commercially favoured resistant potato varieties and concerns surrounding the use of chemical control measures have resulted in G. pallida being an intractable problem to farmers both in the UK and in many other countries. Both PCN species live as parasites and must complete the majority of their life-cycle in potato roots. PCN has a complex interaction with its plant host. Juvenile nematodes are microscopic worms that hatch from eggs in the soil upon detecting a host plant growing nearby, then locate and subsequently invade the roots of the host. The nematode migrates inside the root and selects a single root cell that it transforms into a large specialised feeding cell. The nematodes withdraw nutrient from the specialised feeding cell over several weeks. Each plant can harbour many hundreds of nematodes and their feeding has a dramatic, detrimental impact on the growth and yield of the potato crop. The control of PCN is named as a top industry research priority.
The Agricultural and Horticultural Development Board (AHDB) Potatoes is a statutory levy board, funded by the potato industry. AHDB's remit is to equip its levy payers with independent, evidence-based information and tools to grow, become more competitive and sustainable. As part of meeting this remit AHDB Potatoes provides the sector with information rearding PCN. They offer a web based educational tool and decision justifier that can allow a grower to visualise different 'what if' scenarios related to PCN that are relevant to their enterprise and agricultural practices. The advisory tool shows the implications of a grower's actions on the level of PCN infestation and the effect on the predicted yield. This demonstrates that treatment of an infestation is best tackled early when the levels are low, as this is when the use of nematicides has the greatest effect. The effect on yield is based on mathematical predictions.
AHDB appreciate that the PCN advisory tool requires improvement and updating because while offering valuable advice in certain scenarios the model could reflect outcomes more accurately. We propose to collate data from known sources and collect more data where necessary in relation to specific aspects that affect PCN multiplication such as temperature, tolerance of the potato variety to the pest and the emerging control strategies of biofumigation and trap-cropping. The data will be analysed and used to provide mathematical predictions in an improved PCN advisory tool.

Planned Impact

The application addresses a specific issue proposed and supported by AHDB Potatoes. Development of a PCN population advisory tool that provides robust management advice will allow growers to make better informed management decisions with respect to their own circumstances. The consequence will be improved long term management of the PCN problem and increased yield for the grower. The potato industry is important to the UK economy and it is therefore vital that PCN does not cause a long-term competitive decline in the UK-based potato production and processing capacity relative to elsewhere with a less severe PCN problem (e.g. France, Poland).

Publications

10 25 50
 
Description The work has generated and collated data in relation to factors that affect multiplication of potato cyst nematodes (PCN), such as temperature, soil type, tolerance of the potato variety to the pest and the natural decline rate of the nematode population. The data were analysed and used to provide mathematical predictions in an improved PCN advisory tool that acts as a web-based decision support system for potato growers.
Objective 1. We have determined that there is a very strong correlation between the number of eggs a PCN cyst contains and the outline area of that cyst i.e. cysts are not larger than they need to be to contain the eggs produced. By measuring outline area and knowing how many years have elapsed since the last potato harvest an up-to-date egg count allows the decline rate for an individual population to be established. We have completed evaluation of decline rates for English populations that we defined as G. pallida by PCR. The results define the mean rate of annual decline of G. pallida as 19.6 ± 1.5% but the range is considerable (4.2% to 37%). This mean decline rate suggests management of a population reproducing on a susceptible cultivar requires a 10-year rotation, which challenges the viability of some potato cropping. Decline rates of <10%/year of 15% of fields sampled requires further investigation as rotational control alone requires an unacceptable rotation course of in excess of 15 years. We have also established simple and inexpensive equipment would allow advisory workers to provide estimates on annual decline rates with minimal effort and cost.

Objective 2. The current model includes soil texture as the only environmental influence on yield loss due to PCN. This factor has been shown in the current work to relate to the proportion of sand in the soil type on which potato is cropped.
Rainfall before and just after planting in spring has greater impact than summer temperature. This relates to much of the damage caused by PCN being due to root invasion of young plants by the infective juveniles. Historic spring rainfall in the area where the crop is to be planted provides a proxy value for model use by the grower before spring planting of the potato crop. The model enables the grower to see predicted losses for a given PCN pre-plant density at the historic mean rainfall and the range set by a 1 in 5 year chance of the higher (losses reduced) and lower rainfall (losses increased) in that region.

Objective 3. In addition to cyst samples that the academics have been able to source, our SARIC industrial partner Barworth Research has kindly provided samples with known field histories. We have analysed samples in relation to the effect of a biofumigant brassica in the rotation on the overall decline rate of the nematodes. Results establish a more severe decline rate prevails when this management procedure is adopted. The apparent annual decline is increased to 62.1± 5.5% for the combined effects of the brassica and the natural decline rate.

Objective 4. The AHDB advisory tool has been modified in several aspects, in particular tolerance values have been replaced by determinacy. The latter value is already known for many cultivars as it is relevant to nitrogen application regimes.
Two field experiments have been conducted at Harper Adams University to assess the tolerance of the top 10 most planted potato cultivars in Great Britain to potato cyst nematodes. Each cultivar was grown in the presence or absence of oxamyl. In 2017, under very high population densities (28-304 eggs g/soil) we observed that the cultivars Cara, Maris Piper, Melody and Nectar all produced good yields regardless of nematicide treatment. In 2018, the field experiment was planted in soil with low- moderate population densities (1-57 eggs/g soil) and contained a wider selection of cultivars. Initial findings from this experiment have highlighted significant differences in the development of potato cultivars (ground cover %), which appear to correlate with tolerance and determinacy. It is anticipated that the two experiments, conducted in contrasting conditions, will provide useful field data to inform the revised model. The relationship between determinacy values and data on yield and PCN multiplication will be investigated.

Objective 5: Levels of control achieved by nematicides have been defined from a range of previous field trials. The 2 nematicides available to growers provide similar levels of control with a mean of 75 ± 3.5%. Environmental factors influence the actual level of efficacy achieved which varies from 67 to 97% in successful trials but more importantly less than 50% control occurred in 15% of all trials. This is important risk-related information for a grower to consider.

Objective 6. There was no correlation between decline rates of different PCN populations and their mitotypes as an indicator of genetic diversity.
Exploitation Route The information and improved model resulting from the award could be used by the levy board AHDB Potatoes to inform and educate the grower community about the consequences of decisions they take during the course of the season.
Sectors Agriculture, Food and Drink

 
Description The Agricultural and Horticultural Development Board (AHDB) Potatoes is a statutory levy board, funded by the potato industry. AHDB's remit is to equip its levy payers with independent, evidence-based information and tools to grow, become more competitive and sustainable. As part of meeting this remit AHDB Potatoes provides the sector with information regarding Potato Cyst Nematode (PCN). They offer a web based educational tool and decision justifier that can allow a grower to visualise different 'what if' scenarios related to PCN that are relevant to their enterprise and agricultural practices. The advisory tool shows the implications of a grower's actions on the level of PCN infestation and the effect on the predicted yield. This demonstrates that treatment of an infestation is best tackled early when the levels are low, as this is when the use of nematicides has the greatest effect. The effect on yield is based on mathematical predictions. AHDB appreciated that the PCN advisory tool required improvement and updating because while offering valuable advice in certain scenarios the model could reflect outcomes more accurately. We have collated data from known sources and collected more data where necessary in relation to specific aspects that affect PCN multiplication that has been used to provide mathematical predictions in an improved PCN advisory model. The improved advisory model has been delivered to AHDB to host on its web-site, to inform its levy paying members.
First Year Of Impact 2019
Sector Agriculture, Food and Drink
Impact Types Societal,Economic

 
Description SARIC Translational GCRF/ODA
Amount £18,122 (GBP)
Organisation Natural Environment Research Council 
Sector Public
Country United Kingdom
Start 03/2017 
End 07/2017
 
Title Improved PCN calculator 
Description The aim was to enhance the precision and utility of the UK PCN calculator for management of Globodera pallida. A new enhanced model was generated, incorporating additional parameters, to update and improve a well-established web-based management tool for potato cyst nematode. Some or all the improvements developed in this work are likely to be transferable internationally to the control of G. pallida. 
Type Of Material Computer model/algorithm 
Year Produced 2020 
Provided To Others? No  
Impact A manuscript describing the enhanced model has been submitted for publication. In the future, the model will be used to enhance/replace the web-based PCN management tool that is currently provided by the Agriculture and Horticulture Development Board (AHDB) for public use by growers/agronomists/researchers. 
 
Description 5th Symposium of Potato Cyst Nematode Management 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Industry/Business
Results and Impact Prof Urwin was invited to give a Plenary Talk at this International Symposium, held every 5 years, that acts as a forum for knowledge exchange and discussion of the latest research and development of management practices for nematode pests of the potato crop. The meeting is attended by representatives from academia, government institutes, industry, agronomists, growers and levy boards. The outputs from the project that related to improvement of the AHDB PCN calculator tool were presented. This sparked extensive discussions between attendees and exchange of ideas and opinions between representatives of various international agricultural monitoring and advice organisations.
Year(s) Of Engagement Activity 2019
 
Description AHDB Agronomists Conference 2017 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Professional Practitioners
Results and Impact AHDB invited a presentation of the SARIC project "Development of a PCN population advisory tool that provides robust advice and management" at the Agronomists' Conference 2017, held in Peterborough in December 2017. The Agronomists' Conference is a two-day technical conference covering the latest research developments to help agronomists stay up to date with current research and think differently about agronomy. Dr Bill Watts, one of the researchers associated with the project, presented the results of our research to-date, talking mainly about the results of the PCN tolerance trials that were carried out during 2017.
Year(s) Of Engagement Activity 2017
URL https://cereals.ahdb.org.uk/media/1326637/Main-room-slide-deck-Ag-Conf-day-one.pdf
 
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 AHDB SPot Farm blog 
Form Of Engagement Activity Engagement focused website, blog or social media channel
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Industry/Business
Results and Impact The research of the SARIC project "Development of a PCN population advisory tool that provides robust advice and management" has featured a number of times in the AHDB Strategic Potato Farms Blog that updates growers and agronomists on the latest results and dissemination events occurring on the AHDB Potatoes best practice demonstration farms.
Year(s) Of Engagement Activity 2017
URL http://strategicpotatofarm.blogspot.co.uk/
 
Description Article in Arable Farming Magazine 
Form Of Engagement Activity A press release, press conference or response to a media enquiry/interview
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Industry/Business
Results and Impact The work of the SARIC project "Development of a PCN population advisory tool that provides robust advice and management" was covered by an article in the Arable Farming Magazine's Research in Action feature in June 2018. This article, entitled "PCN Advisory Tool Under Scrutiny", covered the trials that are being carried out to assess resistance and tolerance of potato varieties to potato cyst nematode, with the aim of improving the AHDB's PCN calculator to encompass newer potato cultivars that are gaining in popularity amongst growers. Both Prof Peter Urwin and the coI and researcher at Harper Adams University (Drs Matt Back and William Watts) were interviewed and provided material for the article.
Year(s) Of Engagement Activity 2018
URL https://www.fginsight.com/news/news/research-in-action-pcn-advisory-tool-under-scrutiny-63729
 
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 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