Problems
Light Leaf Spot
Light leaf spot can reduce oilseed
rape yields by up to 40%. It is predominant in the North
and West of England and Scotland.
Last year over 46% of the national
crop suffered from light leaf spot. Work funded by HGCA
has shown that for every 10% of plants affected at green
bud there is a potential 0.14 t/ha yield loss.
Yield Effect
Light Leaf Spot
Symptoms are seen in the autumn as
pale leaf blotches.
The economic response to an early
spring (February-early March) spray against light leaf
spot can be 1-1.5 t/ha, so treatment is well worth while.
The threshold for spraying at stem
extension is 25% of plants infected, but it is advised
to incubate plant
samples in a polythene bag for 1-2 days to determine
infection levels.
High
risk conditions are:
|
| • North
of England and Scotland |
| • early
sown crops |
| • cool,
moist conditions |
| • high
trash or crop debris |
| • susceptible
varieties |
Phoma
Seen as leaf spot and stem canker,
Phoma can reduce yields by up to 50%. It is
the most costly disease in terms of yield.
Last year over 95% of the oilseed rape crop in the UK
was affected by Phoma.
Infection threshold is 10-20% of plants
infected, regardless of the number of spots seen. The
lower threshold should be used on small plants and susceptible
varieties.
This year Phoma is expected
to be at high levels and early.
High
risk conditions are: |
| • early
drillings of winter oilseed rape |
| • short
rotations and block cropping |
| • wet
summer conditions |
| • large
areas of harvested rape |
| • minimal
cultivations |
| • high
trash or crop debris |
| • susceptible
varieties |
Many
growers adopt a two-spray programme starting in
the autumn and followed up in the spring to control
these damaging diseases which can severely reduce
rape yields.
Phoma must be controlled in the autumn
in order to prevent the damaging canker in the
spring. Leaf spotting in the autumn should be
treated within two weeks of the symptoms appearing.
Autumn fungicide treatments prevent the fungus
from spreading down the leaf to the leaf axil
and then to the stem.
The most cost-effective spray timing for light
leaf spot is late autumn from mid-October onwards,
but it is often difficult to see the symptoms
at this time.
|
|
Solutions
The performance of all key oilseed rape fungicides,
including Plover (difenoconazole), Punch C (flusilazole),
Caramba/Sunorg Pro (metconazole), Folicur (tebuconazole),
or Proline (prothioconazole), are enhanced by the addition
of Arma.
Arma works by helping to retain and spread the fungicides
onto the waxy oilseed rape leaf surface and by helping
penetration into the plant where it is needed. It improves
disease control and increases yield by ensuring the
most robust fungicide performance.
Triazole fungicides such as Caramba and Folicur have
additional growth regulation benefits and are widely
used to create a robust plant that will survive and
thrive the autumn/winter and create a canopy that will
optimize yields.
Trials carried out by the University of Kiel
in Northern Germany show the benefits of adding Arma
to a 0.5 l/ha rate of Caramba (see below).
This treatment gave a return on investment of 600%,
compared to only 400% when Caramba/Sunorg Pro was applied
alone at 1.0 l/ha.
Yield Effect
Arma boosts Caramba
Yield Effect
Fungicides and Arma
Disease Control
Fungicides and Arma
Arma
in mix with oilseed rape fungicides: |
| • improves
disease control and increases yield. |
| • boosts
growth regulatory effects |
| • helps
to retain and spread the fungicides onto the waxy
oilseed rape leaf surface. |
| • improves
placement of fungicides onto the plant. |
| • helps
penetration into the plant where it is needed. |
| • works
at low temperatures. |
| • ensures
the most robust fungicide performance. |
| • is
safe to the crop. |
| • ensures
maximum performance in tough conditions. |
|
Products
Oilseed
Rape Special
Other
Crop Specials
