| Incidence of FHB in Winter Wheat |
| Results from the Defra CropMonitor project (1986 - present) have shown that the incidence of FHB in the UK has been sporadic. However, levels of FHB over the past decade (1998-2007) has increased compared to the previous decade (1988-1997). |
| Incidence of FHB at GS 75 in England and Wales |
| Over 80% of the samples assessed during the 2007 survey showed symptoms
of FHB. This is by far the highest level seen since ear assessments began in 1986; the previous high was
recorded in 1998 when 61% of samples had FHB symptoms. Increased disease levels over the last few years,
and in particular in 2007, are likely to be a result of the wet weather during anthesis. Changes in agronomic
practice may also be influencing the level of FHB. |
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| Monitoring of FHB pathogens |
| Since 1998, FHB pathogens have been isolated from diseased wheat ears collected by the survey (data shown from 2000).
The predominant pathogen isolated from FHB symptoms has varied from year to year. Between 1998 and 2003 the predominant pathogen isolated switched between M. nivale/majus and F. poae. In 2005, F. graminearum became the predominant pathogen for the first time. In 2006 and 2007, F. poae and M. nivale/majus were again the predominant pathogens. |
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F. culmorum and F. graminearum are type B trichothecene producers (deoxynivalenol/ nivalenol) and are the major causes of
mycotoxin contamination of wheat grain. Since the start of isolations in 1998 there has been a switch in predominance of these two
pathogens. Before 2002 incidence of F. culmorum exceeded that of F. graminearum. In 2002 the incidence of
F. graminearum exceeded that of F. culmorum for the first time, and in subsequent years this predominance has become more marked.
Factors, which may be attributed to the increased prevalence of
F. graminearum, include weather conditions, changes in tillage practice and the increasing use of maize in rotations. |
| Region incidence - 2007 |
| FHB pathogens were isolated from a large percentage of samples collected from each region.
The lowest levels were found in Yorkshire and Humberside (68%) and the highest in the North East and North West of England (100%).
M. nivale/majus were the predominant species isolated from all regions other than the North West of England where F. poae predominated.
The highest level of F. graminearum was found in the East Midlands, where F. graminearum was isolated from 44% of samples, with on average 4%
of ears per sample infected.
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