Data displays disease dearth

DISEASE INCIDENCE in oilseed rape and winter barley during 2004 was generally low, according latest CropMonitor results.

Rhynchosporium leaf blotch remained the dominant foliar disease for winter barley, while Alternaria dark leaf and pod spot were the only OSR diseases with incidence above the 10-year mean, the results showed.

Despite leaf blotch remaining the dominant barley disease, incidence was still less prevalent than previous years and was well below the 10-year mean, said the Central Science Laboratory‘s Dr Judith Turner

The generally low disease pressures could be due to improved fungicide treatments, or more favourable weather conditions, she added.

Fears over high sclerotinia stem rot levels in OSR after wet weather during flowering were not reflected in the survey.

Levels were low nationally, although epidemics were sporadic and incidence was high in some areas, particularly in parts of the Midlands and the East.

Phoma affected 26.6% of stems nationally, well below the 10-year mean of 44.4%, according to the survey.

“We did seem to see a reduction in phoma incidence this year,” Dr Turner noted.

More detailed analysis of the agronomic reasons behind these 2004 trends will be available from the CSL later this year.