Current: Review of models and data for use in a Virus yellows Decision Support System

Timescale: 6 months - to be completed March 2024
Project Lead: Dr Sacha White, ADAS

Project Summary

Virus yellows (VY) is the most important insect-related issue in UK sugar beet production. VY is a complex of aphid vectored viruses, which includes Beet mild yellowing virus {BMYV), Beet yellows virus (BYV), and Beet ch/orosis virus (BChV). They are transmitted by several aphid species, including Myzus persicae and Aphisfabae, with the former being the most important due to its earlier migration in the spring and increased tendency to spread within crops. The entire UK sugar beet cropping area is at risk from VY.

Main Objectives

Neonicotinoid seed treatments were banned in 2018 and though derogations for their use have occurred since and may occur again, it is highly likely that these seed treatments cannot be relied on in the long-term. In their place, chemical control relies on the application of foliar insecticides. However, only a limited number of foliar insecticide active ingredients and spray applications are permitted meaning that knowing whether and when to use these insecticides to protect the crop during the aphid migration can be difficult. Since the neonicotinoid seed treatment ban, yield losses of between 40-100% were experienced in 2020, primarily due to the warm winter preceding the crop that encouraged early migration of M. persicae. Growers and advisors are in need of decision support systems (DSS) to better understand risk, inform crop monitoring effort and support spray decisions. The current 'Rothamsted model' of VY predicts the proportion of the national crop infected with VY by the end of August but does not provide field­level predictions. Models are needed to underpin a DSS to help growers understand risk at the field level and assist in management decisions. To better inform the scope, structure and work needed to develop such a model, a literature review is required to understand the availability of aphid population, disease dynamics and beet growth models, data for use in parameterising such models and information on treatment thresholds. 

Literature review of following:

• Review the availability and suitability of VY epidemiology models.
• Review the availability and suitability of M. persicae population dynamics and movement models.
• Review the availability and suitability of sugar beet growth models.
• Review the availability and suitability of reliable data to parameterise a VY epidemiology model.
• Review the availability and suitability of reliable data to parameterise a M. persicae population dynamics and movement model.
• Review data on treatment thresholds for controlling M. persicae carrying VY.

The results of the literature review will be used to propose a structure for a future DSS for informing management decisions for VY control at the field level. Knowledge gaps will be identified to understand where further experimental work is needed for parameterising a DSS.
A final report will be produced to collate the results, ensuring that messages are concise and clear. Results can also be presented at the BBRO winter conference in 2024.

Control of aphids and VY is a core priority in BBRO's Crop Protection research. The potential impact of VY on yields is severe (e.g. 40-100% yield reductions in 2020). As part of BBRO's wider body of research into managing VY, this literature review will help understand the next steps in developing effective DSS to support growers and advisors in management of VY. The loss of neonicotinoid seed treatments has also affected vector-virus management in other crops, e.g. Barley yellow dwarf virus (BYDV) in cereals and Turnip yellows virus (TuYV) in oilseed rape. To assist growers and advisors in the management of BYDV, AHDB made an online DSS (the T-sum tool) available in 2019 and commissioned a recently completed project developing an improved DSS. Both DSS guide the use of foliar insecticides, while the latter also provides guidance on non-chemical control, e.g. sow date and varietal tolerance.
Providing sugar beet growers with similar DSS will improve control of VY and reduce crop losses. Such DSS would be of benefit to all UK sugar beet growers and in all years, especially those following a mild winter. Additionally, DSS that rationalises insecticide use so that unnecessary insecticide applications are minimised is a key component of insecticide resistance management. Given that M. persicae has developed resistance to many insecticide modes of action in recent decades, it will be crucial to employ insecticide resistance management that maximises the durability of any insecticide used against the pest.

Outcomes / Key Message For Growers And Industry

Under review
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BBRO is a not for profit making company.
We are set up jointly by British Sugar plc and the National Farmers' Union.

British Sugar
National Farmers' Union