New SeaSoN PoiNterS - ProCam · 2018. 4. 4. · Trials have shown that adding a water conditioner...
Transcript of New SeaSoN PoiNterS - ProCam · 2018. 4. 4. · Trials have shown that adding a water conditioner...
before considering the other limited
alternatives. Try not to spray until
absolutely necessary to avoid
driving further resistance.
Once emerged oilseed rape can be
quite tolerant of CSFB grazing.
It has been suggested that thresholds for damage are when:
• 25% of leaf area is lost at the 1-2 leaf stage
increasing to
• 50% of leaf area lost at the 3-4 leaf stage.
As a group pyrethroids are prone to ‘lock-up’ if applied in
hard water. This means that the effective active ingredient
available for control is reduced - sometimes by as much as
50%. Trials have shown that adding a water conditioner to
the spray water before mixing the insecticide reduces the
in-tank lock-up of the active ingredient The amount of active
ingredient arriving at the site of activity is significantly
increased in the critical period after application.
Promoting early and vigorous
growth of the oilseed rape plants
will be key to enable them to cope
with adult CSFB grazing. ProCam
trials have identified certain foliar
nutrition/growth stimulant products
including Universal Bio, phosphites
and zinc ammonium acetate that
produced significant increases in
oilseed rape root and shoot growth
over conventionally fertilised plants.
As well as CSFB attention will have to be paid to aphids i.e.
Myzus persicae the Peach Potato aphid - the main vector for
the spread of Turnip Yellow Virus (TuYV). Most M. persicae
are resistant to pyrethoids and pirimicarb. Control will rely on
pymetrozine e.g. Plenum and other options e.g. thiacloprid
- Biscaya. Currently M. persicae numbers caught in traps
are low but may rise steeply if temperatures remain high in
September. Your ProCam agronomist will have the latest
information on the optimum timing and product selection to
suppress CSFB and TuYV and promote crop growth.
A major threat to oilseed rape establishment this autumn will
again be Cabbage Stem Flea Beetle (CSFB). The lack of any
neonicotnoid seed treatments means crops will be even more
vulnerable to early adult beetle grazing. Some areas have
had adequate rains to encourage rapid crop germination
and growth but many parts remain dry and crops are slow to
emerge. There are signs, as September starts, that adult CSFB
are emerging from their summer rest period and evidence
of shotholing is being found on early emerged plants. Close
monitoring is needed at this time as this is the stage at which
the crop is most vulnerable.
The beetles can feed on and
destroy the growing point and in
high infestations can kill seedlings
even before they emerge. Once
the cotyledons are through, the
crop is usually more tolerant
of attack. Resistance to the
pyrethroid group of insecticides has been identified within
the CSFB population although the level of the resistance
varies within field populations across the UK. However,
pyrethroids should still be the first starting point for control
New SeaSoN PoiNterSFine weather in August has allowed good progress with harvest and cultivations but the attention is already shifting to weed and pest control in new season crops.
Technical UpdateSEPT ’16
Conventional
Universal Bio
Procam Agriculture Tel: 01763 261592 Fax. 01763 262504Fieldcare South Tel: 01777 839000 Fax. 01777 839111
The dormancy of blackgrass seed shed from this year’s
plants has often been used to give guidance on the most
effective cultivation strategy and the likely benefit of ‘stale
seedbeds’ in reducing blackgrass seed burden prior to
drilling. To date there has been no confirmation of the
2016 dormancy levels. However, temperatures through late
June and early July when blackgrass seed was maturing
were at or slightly above the long term average.
This would suggest dormancy levels may be at least on
a par with last year’s moderate level or even possibly a
little less dormant.
However, the value of any stale seedbed in reducing
blackgrass numbers will be most dependent on the quality
of the ‘seedbed’ - fine and firm to ensure good seed/
soil contact - and the presence of moisture to get the
shed blackgrass seed to grow. Delaying drilling, ideally
into or past mid-October will also allow time for a lot of
blackgrass seed to ‘flush’.
N.B. the dormancy factor only applies to seed shed this
year. Old seed in the soil from previous years will have no
dormancy restrictions and should germinate quickly in
favourable conditions.
The majority of blackgrass seed will germinate in the top
5 cm of soil. This was confirmed in a simple but effective
ProCam trial. A set number of blackgrass seeds collected
from the same population source was planted in pots
at varying depths and the emergence monitored at 14
day intervals. The table below confirms that the majority
of seed in undisturbed ground will germinate from the
surface and the top 5cm of soil.
A shallow cultivation strategy may avoid bringing up
seed from deeper in the soil profile and adding to the
blackgrass burden. However, this will only work if soil
structure is in good order. Any restriction to water
movement through the topsoil will limit the effectiveness
of herbicides and be more conducive to the blackgrass.
So cultivation and drilling strategies need to be adapted
to individual field requirements following soil examination.
Key action points for grass weed control this autumn:
Before drilliNg
• Spray off any emerged blackgrass – in fine,
consolidated, moist ‘stale seedbeds’. There will be
some good opportunities this year, but patience will
be required for optimum benefit. Seed from previous
seasons will germinate quickly after cultivation
- if adequate moisture is available.
• Be flexible in selecting cultivation/drilling strategies.
Be prepared to modify operations to field
requirements.
at drilliNg
• Don’t drill too early! Drilling later allows more time
to remove grass weeds before drilling BUT even more
importantly residual herbicides will work better if
applied to cooler, wetter soils - more likely to be found
in early to mid October than September!
• Attention to seedbed quality is essential. For maximum
residual herbicide effect seedbeds need to be fine and
firm - No Clods! If another cultivation pass is needed
do it!
• Aim to establish a competitive crop. Check Thousand
Grain Weights and adjust seed rates accordingly.
• Drill the worst blackgrass fields last to get the optimum
benefit from a ‘stale seedbed’.
HerBicide StrategieS
• Use a robust pre-emergence residual herbicide
’stack’ and/or sequence ideally with 4-5 different active
ingredients. Trials have shown that increasing the
number of elements from different herbicide groups
in a ‘stack’ improves overall control. Equally important
it minimises the risk of developing resistance within the
grass weed population.
• Apply residual herbicides pre-weed emergence
and within 48 hours of drilling. This becomes more
important with later drilling into moist soils when rapid
grass weed germination and growth can be expected.
graSS weedSControl StrAtegy
2016
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www.procam.co.uk
% Blackgrass Emergence
25-Nov
09-Dec
23-Dec
06-Jan
20-Jan
03-Feb
17-Feb
0cm 29 31 38 41 54 54 54
0-5cm 5 7 9 10 11 11 11
5-10cm 1 3 4 4 5 5 5
10-15cm 0 0 1 1 1 1 1
15-20cm 0 0 0 0 0 0 0