Fusarium head blight (FHB) of wheat can be caused by a number of different Fusarium species, including F. culmorum, F. graminearum, F. avenaceum, F. poae, Microdochium nivale and M. majus. All these pathogens, with the exception of the Microdochium spp. can produce mycotoxins which can have an adverse effect on human and animal health. Historically, F. culmorum has been the predominant toxin producing species in UK grain. In recent years, however, monitoring carried out by the Defra within the CropMonitor project has shown that the incidence of F. graminearum has become greater than that of F. culmorum and incidence of this pathogen, once largely limited to the south west, it is gradually advancing north and east. This is of concern because F. graminearum can cause greater damage to wheat than F. culmorum; both in terms of direct yield loss and but also due to contamination of the grain by mycotoxins which are produced during infection of the wheat ear at flowering. New EU legislation, due to come into force 1 July 2006, will set tolerance limits for toxin contamination of grain caused by Fusarium species.
During the past decade, monitoring data have contributed to the significant progress in understanding the epidemiology and control of FHB, and the relationship between fusarium pathogen levels and degree of mycotoxin contamination in grain. The epidemiology of the individual species and the environmental factors driving epidemics have been investigated, the toxigenic potential of the current UK population has been evaluated, and appropriate strategies for disease control have been developed. However, large gaps in our knowledge remain. As a consequence, reliable estimates of fusarium disease risk are not available to the industry in time to inform spray decisions.
Since 1998, seasonal and regional risk of mycotoxin contamination in grain has been predicted with some success using monitoring data on the incidence of ear blight pathogens and determination of their toxigenic potential. Risk predictions were first issued pre-harvest in 2004 and 2005 and were validated using data on actual mycotoxin levels in harvested grain sourced from a survey funded by FSA/HGCA.
In the interests of food safety, it is important for Defra to develop robust strategies to minimise the risks of mycotoxins entering the food chain and to ensure that the new EU limits on mycotoxin levels in grain are not exceeded. The current project aims to build on current pilot risk schemes by continuing the monitoring of ear blight pathogens in winter wheat in order to provide further data to develop and improve prediction of risks of mycotoxin contamination of grain. The project will involve thorough analysis of existing large-scale datasets which will be supplemented by new specific data generated by this project. The project will also collaborate closely with two related projects on (a) epidemiological research to inform development of risk predictions for mycotoxin contamination in winter wheat (funded by Defra) and (b) monitoring of mycotoxin contamination in harvested grain (funded by FSA). Through this cluster project approach, all three projects aim to collaborate and exchange data to develop new approaches to identify risks from mycotoxin contamination and develop strategies to minimise such risks under changing pathogen prevalence scenarios.