A2O-Lancaster Farming, Saturday, February 22, 1992
‘Vine Decline ’ Adverse To Watermelon Production
ANDY ANDREWS
Lancaster Farming Staff
NEW HOLLAND (Lancaster
Co.) When growing waterme
lons, watch for vine decline.
“The biggest issue in my opin
ion is maintenance of the foliage,
keeping the foliage healthy,” said
Ray Samulis, Burlington County,
N.J. extension agent. Samulis
spoke about high intensity water
melon production on Monday at
the New Holland Vegetable Day.
More than 200 area vegetable
farmers and industry representa
tives attended the day-long event,
which featured a wide array of
programs.
The key to making healthy fruit
and maintaining high vine produc
tivity with watermelons, according
to Samulis, is to keep the foliage
healthy and free of various mil
dews and fungus which contribute
to “vine decline.”
Watermelon sweet
“The foliage is what is making
photosynthates, the foliage is mak
ing sugars, and that’s what's going
to keep the watermelon sweet,”
said Samulis.
The key is to keep close eye on
the vines as they’re growing and to
look for the primary fungus agents,
including anthracnose and downy
mildew, and “getting them out of
there. That’s going to be the big
gest determination of the quality of
your fruit,” he said.
But many procedures must be
employed before the vine stage,
including variety selection (Samu
lis urged growers to select the right
variety, preferably an eastern vari-
Rick Yates, D & L Growers,
spoke about the importance
of greenhouse biosecurity at
New Holland Vegetable Day.
Dan Shantz, Shantz Farm
Market, Allentown, spoke
about the “Secrets of Suc
cessful Fall Crops” at the
New Holland Vegetable Day.
ety), soil maintenance, and trans
planting and fertility management
“Watermelons are one of the
warmest temperature requirement
crops that we have,” said Samulis.
“In fact they grow and thrive at
temperatures which would kill a
lot of other crops. I’ve seen very
few cases where it was too hot to
grow watermelons."
Hold nutrients
In Burlington County (the
largest ag county in New Jersey,
according to Samulis), the soils are
primarily sandy and sandy loam,
which are ideal for the deep-rooted
watermelon plant. But the soil par
ticles, which are extremely large,
don’t retain much fertility. How
ever, the clay soils in southeastern
Pennsylvania are more favorable
to fertilizer retention the small
er the particle of soil, the more
ability to hold nutrients.
According to Samulis, water
melons require good drainange
and are deep-rooting plants. They
can tolerate low soil pH (some
samples in the county tested out at
a soil pH of only 2.8!) and cannot
survive in a high water table
(where the soil porosity is fdled
and offers the plant little aeration).
In the Burlington County reg
ion, irrigation “is 100 percent
required,” said Samulis. “You
cannot grow watermelons without
irrigation.” Of 150 vegetable
growers in the county, only two do
not irrigate and those make a
living out of swampy regions.
Samulis said because of the hot,
dry conditions, regular irrigation
(from 'A to V* inches of rain early
in the season and 1 to VA inches
mid-season) is required. “We like
to recommend drip irrigation,”
said the agent, “but to be quite
honest with you, the majority of
our acreage is not drip irrigation. It
is traditionally irrigated with over
head sprinklers and risers.”
Strict rotation
Watermelons require a strict
rotation schedule in order to stop
the proliferation of root fungus.
In Samulis’ experience, soil
compaction hurts watermelon pro
duction. Heavier-type soils are less
likely to compact, according to
Samulis; rather, lighter, sandy
soils are the ones that have plow
ing layers.
He recommends taking an
18-inch subsoiler and working
over the ground before planting,
because of the importance of clear
ing the way for the deep roots of
the watermelon plant.
Also, the ideal greenhouse
temperature should be 80 to 90
degrees Fahrenheit for seed germi
nation high temperatures are
required especially if using a floor
culture, where the temperatures
are much less. “You can have a
greenhouse air temperature of 75
degrees and you’ll have a root
temperature on the ground of 65 or
even 60 degrees,” he said.
Younger transplant
If using a transplant, it is best to
pick a younger aged one that an
older one. The younger transplant
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