| Arable
Spring target for wild oat
application
Better targeting of wild oat herbicide applications this spring could improve
control of the increasingly prevalent and yield robbing weed. Timing to hit
weeds early and adopting new application techniques could make a
significant difference, according to Syngenta Application Specialist, Scott
Cockburn.
ild oats have become a greater
problem with the weed’s
prolonged germination through
the winter and early spring
escaping control from growers’
focus on autumn grassweed
herbicide programmes.
Wild oats are more competitive to the crop
than black-grass, and there are increasing
reports of the same mechanisms for herbicide
resistance developing, warned Mr Cockburn.
“That makes attention to spring herbicide
applications even more important, to achieve
high levels of wild oat control,” he urged.
He cited wild oats as being especially
difficult to control in the spring because of the
wide application window and fast growing
crops shading the emerging weeds from spray
droplets. In a wet and windy spring there is
often limited spraying opportunities.
“The optimum time to control weeds is whilst
they are small and before they have the chance
to compete with the crop,” advocated Mr
Cockburn. “Although some growers and
agronomists may opt to leave control until later
in the spring, to ensure more late germinating
weeds had established.”
The timing for Axial herbicide, for example,
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does allows for control from first leaf growth
stage, right through to the crop’s flag leaf
sheath extending (GS41).
Mr Cockburn outlined new application
research and trials being undertaken this
season, to look at 90% Drift Reduction Nozzles
for Axial and herbicide programme
applications.
The current recommendation is to use the
angled 3D Nozzle for targeting small grass
weeds up to crop GS30, then moving to
Amistar Nozzles for later applications, when the
crop is larger and penetration required to hit
the target wild oat growing points.
“New designs of angled 90% Drift Reduction
Nozzles have shown good levels of deposition
on small targets in wind tunnel tests, so could
work well for the early timing,” he reported.
“Field testing being carried out now will help
confirm the potential.”
As with the Amistar Nozzles, the momentum
of larger droplets from the 90% Drift Reduction
Nozzles could also achieve greater penetration
of the crop and target weeds more effectively
with later applications, he believed.
Mr Cockburn pointed out that trials have
shown 90% Drift Reduction Nozzles have been
extremely effective in achieving good coverage
and excellent results with other herbicide
treatments, and could prove effective if
conditions are less than ideal for spring wild oat
control.
“The 90% Drift Reduction Nozzles do create
more available spray days, which could be
crucial to get the timing right,” he added.
With all spring spraying this season, he
urged operators to follow the mantra: Go Low;
Go Slow; Get Covered.
To achieve this the sprayer boom should be
set at a nozzle height of 50 cm above the spray
target; to operate at less than 10 to 12 km/hr –
or less if field and weather conditions dictate,
and to use appropriate nozzle design typically
with a water volume of 200 l/ha to achieve good
coverage.
“Delivering better wild oat control gives the
best value for money from any herbicide
application and protects the highest yield
potential for the crop, as well as minimising the
risk of herbicide resistance developing,” said
Mr Cockburn. “Results of this season’s spring
application trials will give growers and
operators clear guidance for the future.”
March 2018 | Farming Monthly | 19