PCC Nov/Dec 2019

VINEYARD REVIEW
WEED MANAGEMENT
IN VINEYARDS
By CRYSTAL NAY | Contributing Writer
From wine grapes to table
grapes and raisins, there are
several ways to prevent and
manage weeds in the vineyard.
Ideally, weeds are managed
while they’re still small, since the
crop is closer to the ground, and taller
weeds can provide easy access for pests,
disease, and other complications.
While industry best practices and
research hasn’t changed significantly
very recently, there has been one
change that farm advisors now recommend
to growers: spray volumes.
“The old recommendations were thirty
gallons an acre,” says Kurt Hembree,
weed management farm advisor for the
University of California Cooperative
Extension, “but it really needs to be
about forty to fifty gallons an acre.”
Farm advisors are seeing better results
for the contact herbicides at this
higher volume, with better coverage
and less weed regrowth, and overall a
cleaner vineyard floor than at the lower
volumes. Everything else, including
timing and materials, remain the same.
The main component of struggling
with weed control is the fact that
even though herbicide labels are very
specific about application timing,
many growers get into the field later
than they should. Sometimes pruning
can take growers into the middle of
winter, and by then there are rainstorms
that can prevent them from
getting out into the field, especially
in vineyards with heavier soils.
Before growers catch themselves
at odds in the winter, there are
things that can be done earlier to
ensure a well-implemented program.
“Late summer and early fall
is a great time to make sure all your
equipment is working properly,”
says Hembree. “Check your spray
nozzles and all your machinery.”
Whichever weed management program
a grower chooses, Hembree insists on
sticking to it, and adhering as closely as
possible to the timings. “As soon as everything
is pruned and the canes come
out of the field, be ready to go. Timing
is the biggest issue. Like in the case of
raisins, you only have a few months
before the canopies touch the ground.”
Another major key for ensuring
spray effectiveness is cleaning up
trashy berms and keeping them
clean. If there is debris at the base
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26 Progressive Crop Consultant November / December 2019