- Phoma leaf spot was the disease most commonly found in the spring (98.0% crops
affected), and was found in all regions surveyed. Incidence within crops was similar to
last year with 42.1% plants affected compared with 45.4% plants affected in 2005. Regional incidence
followed trends seen in previous years surveys, with lower incidence in the North.
- The national incidence of light leaf spot (14.0% crops affected) was lower than the previous
year (21.4% crops affected). However, there was a higher incidence within crops with 4.9% plants
affected compared with last years 1.8%. The severity of the disease was also higher than in 2005,
with a national mean of 0.4% leaf area affected compared to only trace levels (less than 0.05% leaf
area) found last year. Regional trends in incidence of light leaf spot also followed those seen in
previous seasons, with the highest incidence seen in the North and the South West.
- Incidence of downy mildew was recorded at similar levels to last year with 21.0% plants and
3.6% crops affected, compared with 28.6% plants and 2.2% crops in 2005. The highest incidence of
downy mildew was found in the South West region and the lowest found in the East.
- The incidence of white leaf spot, with 5.0% crops and 0.6% plants affected was higher than in
the previous year, when the disease was not recorded in any region in the spring. White leaf spot
was only found in the East and South West regions, with the highest incidence being in the South
West.
- Alternaria leaf spot was found at lower levels than in 2005, with 9.0% crops and 0.6%
plants affected, compared with 12.2% plants and 1.2% crops last year. Alternaria was not
found in the South East or South Western regions.
- Powdery mildew was recorded in the Midlands & West only, at a low incidence of 6.3% crops
and 0.3% plants affected. Ring spot and Botrytis were not found in any crops surveyed
in spring 2006.
Incidence of diseases on the leaf - % crops affected
Incidence of diseases on the leaf - % plants affected
Regional incidence of diseases on the leaf - % crops affected
Regional incidence of diseases on the leaf - % plants affected
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