Current: Supporting new IPM decisions using virus yellows model (StatBeet)

Timescale: 1st Jan 2024 - 31st December 2027
Project Lead: Andrew Mead, Rothamsted Research, partnered with James Bell, Keele University
Project Sponsor: BBRO total cost £506,481

Project Summary

This project will combine statistical analysis and both stochastic and simulation modelling approaches applied to a wealth of data (i.e. from: BBRO experiments and field assessments; the Rothamsted Insect Survey suction trap network; British Sugar field surveys and WeatherQuest meteorological forecasts), to provide strategic insights into the sugar beet VY system.

Main Objectives

Virus Yellows (VY) is transmitted by three aphid vectors that circulate in a region of 18,000 km2 in which more the 90,000ha of sugar beet is grown, producing 8 million tonnes of sugar beet annually.  The EU ban on neonicotinoids in 2018 fundamentally impacted the industry, with the subsequent use of Thiamethoxam treated seed only available under a Defra derogation when the ‘Rothamsted’ VY model predicted incidence above a threshold.  In 2020, when the seed treatment was not available, virus levels averaged 38%, at a cost to the industry estimated to be £67M by Defra.  This project will combine statistical analysis and both stochastic and simulation modelling approaches applied to a wealth of data (i.e. from: BBRO experiments and field assessments; the Rothamsted Insect Survey suction trap network; British Sugar field surveys and WeatherQuest meteorological forecasts), to provide strategic insights into the sugar beet VY system. This will support future management, intervention, and mitigation decisions for the control of VY in sugar beet.  These changes will support future decision-making challenges, such as alternative intervention strategies for managing VY infections.  A particular focus of this proposal is to use statistical modelling to explain the spatial heterogeneity of infection levels seen, suggesting the need for regionalisation below the current ‘national’ scale.

Main Objectives

The work packages below will provide new risk-based forecasting tools, regionalisation metrics capturing spatial variation and an evaluation of control and mitigation strategies through simulation modelling. This approach is aimed at supporting BBRO, British Sugar and the growers to make management decisions to reduce virus yellows impact.

We will address three components in separate but interlinked work-packages (WPs). 

WP1 (Advancing and extending VY forecasts and incorporating alternative control strategies) will use Bayesian and stochastic modelling approaches to incorporate known aphid metrics and daily variation in vector numbers, improving predictions of migration pressure and ultimately refine estimates of VY incidence over time. Ensemble meteorological model forecasts will be combined with observed weather data to provide earlier pre-season forecasts to meet industry demands. We will develop VY forecasts for dates into the growing season and combine with the ensemble meteorological forecasts to guide decisions on within-season interventions.  All forecasts will be presented using both the current confidence-interval approach and a new risk-based approach. It is expected that Defra will follow the EU and not allow further derogations, hence the need to understand the impact of alternative control strategies on VY incidence. Using data from BBRO efficacy trials, we will consider how the timing of different control strategies, such as insecticide sprays or new bio-insecticides, can be used to change the course of primary and secondary infections and hence interrupt and delay the development of virus in the crop. 

WP2 (Regionalisation of forecasts and spatial associations) will apply GIS approaches to land-cover and other spatial layers to describe variation in virus characteristics across the sugar beet landscape, and hence examine the robustness of potential management regions (e.g. North v. East, Factory Areas, NCAs). We will also identify ‘natural’ geographical areas, using self-organising maps and other clustering approaches, as alternative management regions. Within each sub-region, landscape characteristics including lacunarity/connectivity, land-cover variability and other fragmentation metrics will be used to explain the spatial variability in relationships between crop, virus, and aphids to develop more regional forecasts, supporting WP1, with additional data from remote-sensing activities combined with models for aphid population dynamics to better understand the within-crop movement of aphids and virus.

WP3 (Forecasts, synthesis and a simulation environment) Annual pre-season forecasts will continue to be provided, updated to incorporate developments from WP1 on the use of weather forecasts, within-season aphid population dynamics and potential alternative control strategies, and from WP2 on regional and landscape-scale variation in virus impacts.  A simulation framework will be developed to combine models for sugar beet growth and development, aphid population dynamics, and virus spread and development, enabling the exploration of different combinations of strategies on the control of virus yellows, incorporating other developments, including an improved understanding of mature plant resistance and variation associated with varietal differences, from associated BBRO-funded research.

 

Outcomes / Key Message For Growers And Industry

Under review
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We are set up jointly by British Sugar plc and the National Farmers' Union.

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National Farmers' Union