Combating resistance to aphicides in UK aphid pests.
Supported by the Chemical Regulation Directorate (CRD), and a consortium of agrochemical companies and levy boards, this project provides research on aphicide resistance management for the UK farming industries and up-to-date information for agronomic and regulatory procedures. This is heightened by the occurrence of control failures with neonicotinoids against M. persicae in southern Europe. The presence of resistant aphids in the UK would have very serious repercussions for neonicotinoid treatments on sugar beet. The project monitors the response of field-collected live samples of M. persicae to a range of novel aphicides and also monitors for established forms of resistance. Vigilance is essential to safeguard the contribution of these compounds to aphid pest management in the UK, as resistant aphids that cannot be controlled will cause crop losses.
Mitigating new threats from virus yellows: monitoring aphid populations and insecticide resistance to maintain control
To optimise and sustain the use of insecticides on beet by providing forecasts and up-to-date information on the timing and abundance of aphids, their virus content and the precise insecticide resistance mechanisms present. This project builds on successful previous projects centred on data provided by the Rothamsted Insect Survey’s aphid monitoring network of suction traps, with two important developments: i) testing for two new insecticide resistance mechanisms, to pyrethroids and neonicotinoids and ii) the inclusion of aphids from the network of yellow water pan traps in the resistance testing to add information on local variability. Forecasts of the timing and size of aphid migrations will be provided and will aid decisions on aphid control early in the growing season of crops.
Beet cyst nematode: control and rotational issues with brassica species
The significance and importance of oilseed rape and other brassica species in sugar beet rotations is increasing. An appreciation of these rotational issues and the implications of other control strategies for different nematode species are needed. For example, certain growers in East Anglia are now growing a five year rotation of rape, cereal, beet, cereal, rape. In addition, green manures of various mustard species are being deployed on farm in the late summer to improve soil health, or to try and provide alternative strategies to control potato and/or beet cyst nematode via the interruption of their life cycles or biofumigation, or a combination of both strategies. Therefore, it is critical that the appropriate brassica varieties are adopted on farm in order to prevent an indirect acceleration of the populations of these (or other) nematode species.
Maximising sugar yield via fungicides
Previous fungicide trials have shown that the application of a single fungicide can give yield benefits of up to 8 adjusted t/ha and, from a two-spray strategy, a potential further 10 adjusted t/ha. The fungicide trials have enabled the industry to optimise disease control, green-leaf cover and, ultimately, yield depending on harvest date. Current BBRO advice recommends a two spray approach. Positive benefits of a three-spray approach were demonstrated in 2011, although this was not evident in 2012. These studies continue to fine-tune advice regarding application timing and lifting date and provide a more robust advisory system for communicating when to apply products to maximise profitability of the crop, linked to the InnovateUK : SPOREID project.
Impact and novel control of leaf miner (mangold fly)
The larvae of the mangold fly (Pegomya hyoscyami) mine extensively sugar beet leaves, resulting in blisters that reduce photosynthetic area, increase sensitivity to herbicides and increase the likelihood of frost damage. Two or three generations of the pest can occur in the year and while the most vulnerable stage of the crop is currently protected by neonicotinoid seed treatments, later infestations can cause significant damage once seed treatments have worn off. The use of foliar insecticides to control late season mangold fly infestations are currently of limited benefit as they need to be applied to larvae before they enter the leaves. The project is evaluating alternative control strategies and a method to identify adults from water traps to monitor population.
Discovering the source of sugar beet infection and re-infection by rust and powdery mildew
Powdery mildew and rust can cause sugar yield losses of up to 20% and 14% respectively. Little is known about (1) the level of diversity of E. betae races, (2) the source of annual infection and (3) the races that re-infect after fungicidal treatment. Wild Beta could act as pathogen reservoirs, causing subsequent infection (and re-infection). In addition, these wild infections could be a source of novel virulence genes that overcome cultivar resistance. Therefore, it is important that a clearer understanding of mildew and rust population diversity to identify the causes of infection dynamics and improve future control strategies or resistance management.
Virus yellows: aphid monitoring and alternative control strategies using existing/novel insecticides
Virus yellows is a greater problem in the UK than anywhere else in Europe due to the influence of our maritime climate. Virus threats are accentuated by the ongoing development of insecticide resistance and climate change. An integrated disease management toolkit is required that utilises resistant varieties and accurate disease forecasts to enable timely and appropriate applications of insecticides. This system will slow the development of insecticide resistance in aphid populations, thus prolonging the life of active ingredients, whilst helping to reduce the amount used. This is crucial with the recent appearance of neonicotinoid resistance within mainland Europe. To achieve durable control of the viruses, aphid populations will be monitored and assessed for resistance and virus content in order to allow us to advise growers of risks to their crops. Existing and/or new insecticides will be assessed providing a potential novel approach for controlling these viruses.
Monitoring the future risk of rhizomania
Previously, rhizomania had a major economic impact on the UK industry, potentially decreasing yields by up to 70%. The development of partially-resistant varieties by the breeders have made a major contribution to protect the yield potential of the UK crop. However, new strains of rhizomania, capable of overcoming varietal resistance, were identified in the UK (e.g. P-type (2001) and the AYPR (2007) strain). Such strains pose a serious threat to current ‘resistant’ varieties, although varieties with an additional resistance gene (Rz1 + Rz2) have been developed and released commercially that yield in the presence of these new strains (e.g. Sandra KWS). If no further sources of novel resistance genes are identified, the likelihood of a future breakdown in rhizomania resistance is high. The project monitors the incidence, distribution and strain variation of the rhizomania virus and assesses any future novel resistance to the virus.
Innovate UK: Innovative disease monitoring and diagnostics for improved efficiency of crop production (SPOREID)
SPOREID is a new project designed to minimise the impact of disease on yield of the UK sugar beet crop. The yield potential of the UK sugar beet crop is c.130 t/ha compared to an average yield of 70t/ha. One of the factors responsible for this yield gap is foliar diseases which can reduce yield by more than 50% and, whilst current practices prevent yield losses of this magnitude, it is estimated that 10% yield is lost to foliar diseases, representing £24M per year. Climate change may lead to increasing pressure from existing or 'new' emerging diseases, which require increased crop protection. Improved disease management will allow growers to increase the productivity, sustainability and profitability of the crop. This project will bring together novel diagnostic tools, crop disease modelling and yield forecasting to underpin grower decision making and investigate the potential impact of emerging diseases on the crop.
Innovate UK: A novel pre-breeding strategy to reduce dependence on insecticides for virus yellows control in sugar beet
Virus yellows is a major economic disease affecting sugar beet; its impact is particularly significant in the UK due to our maritime climate, and will be exacerbated by potential restrictions on neonicotinoid use and developing insecticide resistance in aphid vectors. Development of genetic resistance is therefore critical to maintain viral control. The consortium has explored the genetic diversity found in beet relatives, identifying candidates exhibiting resistance and tolerance to virus yellows. A novel phenotyping approach has been developed to quantify resistance/tolerance traits, and to identify genes which protect against foliar damage. Using this unique toolkit, tolerance quantitative trait loci (QTL) will be introgressed into modern breeding material, with hybrids assessed for foliar health and yield and new resistant candidates will be characterised, QTL identified, and molecular markers developed for future breeding, ultimately producing new virus-resistant commercial varieties.