November 2022 - 20

GRAPES
UF evaluates grapes for Florida winemaking
By Doug Ohlemeier
Assistant Editor
University of Florida (UF) researchers
are searching for the best winegrape
varieties that would be suitable for
growing in the Sunshine State.
In August, UF's Institute of Food and
Agricultural Sciences (IFAS) sponsored
its fourth grape field day. The event, at
the UF/IFAS Plant Science Research and
Education Unit (PSREU) in Citra, Florida,
was designed to update growers, and
researchers discussed grape performance
and evaluation. The field day, which
also included a winemaking workshop,
included demonstrations on planting,
irrigating, pruning and trimming.
While UF isn't breeding Muscadines,
Ali Sarkhosh, a UF/IFAS assistant
professor of horticultural sciences, is
growing and evaluating varieties in
UF test plots released at Florida A&M
University, the University of Georgia
(UGA) and the University of CaliforniaDavis.
UF provides growers information
on Muscadine cultivar performance for
wine production and fresh market sales.
In Florida, at least 50 growers have
1,500 acres, about 95% of which is
Muscadines. Of that acreage, more than
85% is for wine, according to USDA
statistics cited by Sarkhosh. He estimates
winegrape acreage is closer to 90% in
contrast to Georgia and North Carolina,
where about half goes to wine.
Late summer harvest
Growers in the Sunshine State typically
begin harvesting the third week of July
in the Orlando region before production
continues north, to the central Florida
area of Gainesville-Ocala as well as
into the Panhandle region, including
Pensacola and Tallahassee. Muscadines
harvest into early September with most
winegrapes finishing in late August,
Sarkhosh said.
Because of humidity and more
intense heat, south Florida sees limited
production. The major challenge of
growing in the southern part of the
peninsula is that the higher temperatures
don't allow vines to naturally defoliate,
which negatively affects the following
year's production, Sarkhosh said.
Muscadines cultivars grown at PSREU
include Carlos, a white varietal, and
Nova, a red, longtime varietals used in
winemaking. They are gown along with
some UF-developed fresh market varieties.
UF is reviewing the performance of 13
newly bred UGA muscadines for Florida
production. The grapes are harvested and
measured for characteristics including
size, berry quality, sweetness and acidity.
Sarkhosh plans to generate practical
information for growers on the varieties'
productivity and usefulness, Sarkhosh said.
Florida opportunity
For Florida, the key is to produce
grapes in unique production windows
20 | FruitGrowersNews.com
Ali Sarkhosh, University of Florida assistant professor of horticultural sciences, examines Chenin Blanc grapes. Photos: UF
by harvesting earlier and avoiding
overlapping with Georgia Muscadines.
" It's very important here that we
harvest earlier than any other state, " he
said. " Overlapping would negatively
impact prices. "
Though Muscadines are native to
the South, Pierce's disease is one of the
biggest challenges of growing them.
Fungal and bacterial diseases can
attack and damage grapes in Florida,
destroying vines in less than two years.
Similar to how citrus greening is spread,
the glassy-winged sharpshooter vector
transfers bacteria to vines.
Thrips, aphids and grapefruit borers
and other undesirable insect pests cause
significant damage. The pests, however,
are manageable.
In Florida, 40 wineries grow
Muscadines. Another 15-20 growers grow
for the fresh market, primarily u-picks.
" When you look at the USDA data, you
can say it (Muscadines production) has
been growing at a rate of 3 to 4% a year, "
Sarkhosh said. " Wine and wineries are
related to agritourism. People are wanting
local products. "
Grape staple
Muscadine grapes have been a longtime
core of the vineyards at Lakeridge Winery
and Vineyards in Clermont, Florida,
and San Sebastian Winery in Saint
Augustine, Florida. Ideally, muscadines
would produce at least 10 tons an acre
and possess even ripening and disease
resistance and contain high juice yields,
appealing sensory characteristics and
good fruit chemistry for wine, said Jeanne
Burgess, vice president and director of
winemaking operations.
" Muscadine grapes are uniquely suited
to Florida's climate and soils, " she said.
Burgess cited viticulturist Richard Smart,
At the Plant Science Research and Education Unit in Citra, Fla., UF researchers are
evaluating grapes that would grow well in Florida's challenging climate.
who called them " God's gift to viticulture "
because they are relatively easy to grow,
resistant to many diseases, provide
bountiful yields and thrive in the South's
heat and humidity.
" There are few species of grapes around
the world that can lay claim to that, "
Burgess said. " The native Muscadines is
the eternal flame that kindled renewed
interest in Southern winemaking. It
is the backbone of grape growing and
winemaking in this region. "
Varieties in development must repel
diseases. Decades ago, the Carlos and
Noble varieties were selected for their
disease resistance. Both varieties are selffertile
and only mildly susceptible to black
rot, bitter rot and angular leaf spot. Under
stress, Carlos is susceptible to Pierce's
disease, while grape root borer can harm
all Florida grapes, Burgess said.
At a block in Citra planted in 2021,
Sarkhosh evaluates Pierce's diseaseresistant
varieties for UC-Davis. The
plot is also evaluated for performance
and how it can handle hot temperatures
and the region's humid climate.
Muscadine grapes at the University of
Florida's Citra, Fla., vineyards.
The Chenin Blanc variety, planted
several years ago, is being tested for
Pierce's disease resistance. Because
funding ended, the project isn't
continuing. " It is a very nice grape for
white wine, a common grape cultivar, "
Sarkhosh said. " It's been doing well here
the last few years, growing a nice grape.
We have been looking at it to see what
kind of production we can have and
production practices like covering and
netting to eliminate disease impact and
harvest quality wine. " FGN

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November 2022

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