CropMonitor

Latest results - Summer 2012

Stems and pods of twenty-five plants from each surveyed crop were assessed visually at pod ripening for symptoms of disease.

The proportion of crops affected by phoma canker (83% crops affected) was lower than in 2011 (96% crops affected). Incidence within crops was also lower with 20% stems affected compared to 37% stems affected in 2011. This summer, the incidence of phoma canker was also lower than the long term mean (2001-2010) of 86% crops and 33% stems affected. The incidence of total phoma (phoma canker and phoma stem lesions), at 88% crops and 25% stems affected, was lower than last year when 97% crops and 40% stems were affected. The highest incidence of phoma canker occurred in the South East, where 92% crops were affected, and the region with the lowest incidence was the South West where 78% crops were affected.

Light leaf spot on the pods was recorded on 82% crops and 35% plants. This is the highest incidence of light leaf spot on the pods since 1988 (when 95% crops and 40% plants were affected) and markedly higher than last year (when 33% crops and 5% plants were affected) and the long-term mean (2001-2010) (37% crops and 11% plants affected). On the stems, the incidence of light leaf spot (97% crops and 63% stems affected) was the highest recorded since the survey began in 1987. Light leaf spot was found in all regions of the survey, with the South West having the highest incidence of the disease on the pods. On the stems, 92% crops were affected in the East. This was the only region that did not have 100% crops affected by light leaf spot.

Levels of powdery mildew on the pods were lower than last year with 13% crops and 2% plants affected compared with 14% crops and 3% plants in 2011 and markedly lower than the long-term mean (2001-2010) of 33% crops and 13% plants affected. On the stems, 17% crops and 4% stems were affected with powdery mildew, this was also lower than last year when 29% crops and 8% stems were affected and the long term mean of 33% crops and 14% stems affected. Powdery mildew was found on crops from all regions in the survey, with the lowest incidence in the North.

Sclerotinia stem rot affected 10% crops and 2% plants. Although incidence of the disease was higher than last year, when 5% crops and 1% stems were affected, it was lower than the long-term mean (2001-2010) of 20% crops and 3% stems affected. Sclerotinia stem rot was found in all regions in the survey, with the highest incidence in the Midlands & West (where 32% crops and 8% stems were affected) and the lowest in the North (where 5% crops and 0.2% stems were affected).

Alternaria pod spot was recorded on 76% crops and 17% plants. This is higher than in the previous year when 58% crops and 9% plants were affected, but similar to the long-term mean (2001-2010) of 70% crops and 22% plants affected. On the stems, Alternaria was found at very similar levels to last year, with 5% crops and 0.4% stems affected compared with 5% crops and 0.2% stems in 2011. Alternaria pod spot affected crops in all regions in the survey, with the Midlands & West having the highest incidence (90% crops and 21% plants affected). On the stems, the region with the highest incidence was the South West, with 22% crops and 1% stems affected. The region with the lowest incidence on both pods and stems was the North.

Botrytis was recorded at higher levels than last year. On the pods, 91% crops and 38% plants were affected compared with 88% crops and 25% plants affected in 2011. The incidence on the pods was markedly higher than the long-term mean (2001-2010) of 49% crops and 14% plants affected. On the stems, Botrytis was recorded at markedly higher levels than last year, with 34% crops and 8% stems affected compared with 1% crops and 0.1% stems affected in 2011. The incidence of Botrytis on both the pods and stems was markedly higher this year than the long-term mean of 49% crops and 14% plants affected on the pod and 15% crops and 1% stems affected on the stem. On the pods, Botrytis was recorded in all regions in the survey but on the stems, it was not recorded on any surveyed crop in the South East region.

Incidence of Verticillium wilt was recorded for the second time in the survey. 10% crops were found to be affected and within crops, 1% stems were affected by the disease. This was slightly lower than last year when 18% crops and 2% stems were affected. Verticillium wilt was not found in the Midlands & West or the South West regions in the survey. The East was the region with the highest incidence with 18% crops and 3% stems affected.

Downy mildew was not recorded on the pods or stems of any crop in the survey for the second year running.

* Please note – no verticillium data available for 2001-2010 *

* Please note – no verticillium data available for 2001-2010 *