RAPID ACCESS TO THE LATEST REGIONAL CROP PEST AND DISEASE LEVELS 		HGCA logo
CropMonitor > Winter Oilseed rape > National Surveys  


2003/2004 SURVEY: SUMMER ASSESSMENT 2004

Stems and pods of twenty-five plants from each surveyed crop were assessed visually at pod ripening for symptoms of disease.
 
  • With the exception of Alternaria, disease levels on the stems were lower than in the previous year. Levels of Alternaria on the stems rose from 3.3% stems affected in 2003 to 5.3% stems affected in 2004.
  • Alternaria and Botrytis were the only diseases on the pods to be recorded at higher incidence in 2004 compared to 2003. Incidence of dark pod spot rose slightly from 30.6% plants affected in 2003 to 35.2% in 2004, while Botrytis rose from 0.9% plants affected to 9.5%.
  • Levels of light leaf spot were lower than in recent years. The highest incidence on both stems and pods was recorded in the Northern region where 10.2% plants showed pod symptoms and 13.5% plants showed stem symptoms. Light leaf spot was not recorded on either stems or pods in the South West region.
  • As in previous years, incidence of phoma canker was high with 92.8% crops affected. However, incidence within crops had decreased from 69.7% stems affected in 2003 to 26.6% stems in 2004. Phoma pod spot was found at trace levels in all regions except the South west where no phoma pod spot was recorded.
  • Incidence of powdery mildew on the pods, at 6.3% pods affected, was much lower than in 2003 (42.3% pods affected) when the highest levels were recorded since the survey began. Powdery mildew was recorded in all regions.
  • Sclerotinia stem rot was recorded in all regions with a mean incidence of 12.4% crops affected. The highest incidence was recorded in the Midlands and West (22.2% crops affected) and Northern (18.2% crops affected) regions. The lowest incidence was recorded in the East where only 2.9% of crops showed symptoms.
  • White leaf spot was not recorded on pods in any region, and downy mildew was not recorded on stems from any region. Downy mildew on the stems has not been recorded in the survey since 1991.


Incidence of diseases on the pods - % plants affected


Incidence of diseases on the stems - % plants affected


Regional incidence of diseases on the pods - % plants affected


Regional incidence of diseases on the stems - % plants affected


 
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