Home' Grower : November 2013 Contents 30 The South Australian Grower -- November 2013
Workshop series work
out ways to reduce drift
By JACINTA ROSE
AS urban environments
encroach on grapegrowing
regions and organic food
production continues to grow,
the issue of spray drift has become
Rising costs and far-from-ideal
economic conditions also mean
grapegrowers can ill afford to be
using more spray than they need
to.Achieving a thorough spray cov-
erage on the vine canopy without
using high volumes of chemicals
is no easy task, but grapegrowers
across the country have been given
a helping hand to improve efficien-
cies and cut spray drift.
The Grape and Wine Research
and Development Corporation ran
a series of workshops across key
winegrowing regions in October,
where Cornell University spray
application specialist Andrew
Landers shared his immense
knowledge on vineyard spraying.
At one such workshop in the
Clare Valley on October 14, grow-
ers from across the production
scale gathered to listen to New
York-based Dr Landers, who said
spray drift was largely avoidable and
should be prevented.
"Off-target losses are a waste
of money and chemicals, not to
mention the risk of damage to the
environment and the perception of
growers by the public that comes
from having half your spray drifting
away," he said.
He said growers should ensure
as much spray as possible is hitting
the vines, as ill-directed spray often
vanished into thin air.
"On a warm day, the water com-
ponent of small droplets -- about
70 microns or less -- can evaporate
before it has hit the canopy, espe-
cially if it has been sprayed into the
air and not directly onto the vine,"
"Spraying chemicals anywhere
else but on the vines is a waste of
time and money."
He recommended growers use air
induction nozzles on their sprayers
to cut spray drift, but was not so
enthusiastic about adjuvants added
to the spray tank to stop drift.
"With air induction nozzles,
there's an air bubble incorporated
in every droplet of spray, and when
the droplets hit the target, they go
'splat', but they don't bounce off
like a large droplet usually would,"
"Adjuvants, on the other hand,
may or may not work. We did a
study on field boomsprayers and
out of six treatments, two actually
had increased drift over water.
"Before you rush out and buy
anything, why not change your set
up from a physics point of view,
rather than a chemical point of
Dr Landers believes air speed is
crucial to cutting spray drift and
improving spray efficiencies.
"We currently change the liquid
flow rate with different size cano-
pies -- why not change airflow to
match the developing canopy?" he
He said many grapegrowers used
air or fan speeds that were too high
for ideal coverage.
"While air helps to shake the
leaves in the canopy to improve
penetration, too much air can push
spray past the vine and shake off
any spray already applied," he said.
"Rather than just go with the
highest air speed, you want to get
the air coming out of the sprayer
to meet around the canopy. That
creates turbulent air which helps
get better coverage, even on the
back of the leaves."
By testing coverage using food
dye and water or looking for
turbulent air with just the fans
on, growers can identify areas for
If airflow appears to be too high,
air speed can be reduced by running
the gearbox in low speed, changing
the fan blade pitch or reducing the
PTO speed. Dr Landers said a 25
per cent drop in PTO speed could
cut drift by 70pc.
"For those with a Quantum Mist
sprayer, the newer ones have a
variable speed hydraulic or electric
motor to drive the fan, and it's easy
to make adjustments from the cab
this way," he said.
Air induction nozzles cut drift
Tunnel sprayers offer big
Air speed key to good
The Grape and Wine Research and Development Corporation's spray
application workshops was presented by Cornell University spray expert
Andrew Landers and the corporation's Adrian Loschiavo.
A tunnel recycling sprayer covers two rows at once and can greatly
reduce spray use.
Clare Valley grapegrowers listen to Andrew Landers' presentation.
While the range of sprayers
used in vineyards across the Clare
Valley was diverse, Dr Landers said
tunnel-recycling sprayers were the
way of the future.
"Using a tunnel sprayer and air
induction nozzles brings a 99pc
drift reduction," he said.
Tunnel sprayers alone could
reduce drift by 90pc, while also
reducing the amount of pesticides
used per hectare by 30pc on
"It's particularly effective during
early applications, when we've seen
85pc recycling," he said.
"While the cost of these machines
can be high, you must weigh up the
cost of this against the cost of not
farming. If you get caught up in
a drift case, costs mount and they
can quickly beocme a real threat to
your farming future."
GWRDC program manager
Adrian Loschiavo updated growers
on the increased label restrictions
of many chemicals, as well as spray
"There'd definitely a change in
the landscape of what we're used to
reading on labels," he said.
Labels now contain detailed
restrictions aimed to cut spray drift,
such as wind speed ranges and
downwind no spray zones.
"With spray diaries, there's a
requirement for grapegrowers to
offer information to their buy-
ers regarding the sprays applied.
Depending on who the buyer is,
they'll have more -- or less -- infor-
mation they require, but many are
tending to want more informa-
tion," Mr Loschiavo said.
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