A Vegetable Crops Extension Publication
lHoticultual Kci enca Department P.O. 110690 Gaincsvill. F 32611 Telepbn (352)392-2134
,VEGETABLE CROPS CALENDAR
-:.:.7 ,, Managing Stress in Vegetable Crops
Pumpkin Variety Trial, Fall 1998
Request for Pesticide Needs
~Florida Record-size Vegetables Through May 1999
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' UNIVERSITY OF Cooperative Extension Service
. FLORIDA Institute of Food and Agricultural Sciences
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VEGETARIAN NEWSLETTER Maj 1999
The Vegetarian Newsletter is now
available on the internet. The website is
Vegetable Crops Calendar
Managing Stress in Vegetable Crops
No, we're not talking about how to
deal with Y2K problems, a volatile stock
market or even the uncertainty of farming in
the new millennium. We're talking about
plant stress in vegetable crops, more
specifically stress triggered by salts and hot
weather. This time last year we were
dealing with too much water and (among
other things) salt problems associated with
solubilization of excess fertilizer salts in the
bed. Here we are, a year later, and we're
still dealing with salt problems, but for a
slightly different reason not too much
water, but too little! With almost perfect
growing weather from a disease standpoint,
most area crops have flourished, with
excellent fruit set. There have been
instances in a number of fields around the
state, however, where salts have been a
problem, both in non-mulched crops such
as beans, and in mulched crops such as
tomatoes and watermelons.
Plants vary in their sensitivity or
tolerance to soluble salts in the soil
solution. Crops which are the most
sensitive include beans, carrots,
strawberries and onions (threshold EC
values around 1.0 dS/m). Moderately
sensitive crops include pepper, corn,
potatoes, cabbage, cucumber, and tomato
(threshold EC 1.2-3.2). Moderately tolerant
plants include beets and zucchini squash
(threshold EC 4.0-4.7). (Knott's Handbook for
Vegetable Growers, 4th edition). Usually it is
not the salts themselves that are toxic, but the
reduction in water uptake. As the soluble salt
concentration in the soil increases, plants
have a harder time extracting water from the
soil solution. Variables such as plant age,
soil type and environmental conditions also
affect salt sensitivity; thus, soluble salts
become more critical under the hot, dry and
windy conditions we have seen this spring.
Excess salts in irrigation water can contribute
to the total salt problem, especially wells in
coastal areas, or very deep wells which can
be affected by saltwater intrusion under
unusually dry conditions. Where poor quality
irrigation water is used or where there is a
field history of salt problems, low-salt index
fertilizers are less likely to aggravate the
Fertilizer rate and placement can affect
soluble salt problems which are then
magnified under drought conditions.
Following recommended fertilizer guidelines
and paying careful attention to placement can
minimize problems. In the absence of rainfall
to either dilute or leach fertilizer salts down
past the root system, what can be done?
Typically, soluble salts are less of a problem
with drip irrigation systems because lower
amounts of in-bed fertilizer are used due to
the ability to fertigate. In addition, with drip
irrigation the movement of soluble salt laden
water is down and away from the plant. In
seep or subsurface systems, the movement of
water is upward, towards the highest point of
the bed which is typically the plant hole. As
water is evaporated from the soil surface
around the plant, salts become more
concentrated around the plant root system.
For this reason, lowering the water table by
VEGEARIA NEWLETTR Ma 199
pulling deeper ditches can be a double-
edged sword. While some salts may move
with the water as it drops lower in the bed
or below, the salts that are left will
concentrate as the soil dries. Conversely,
raising the water table may also defeat the
purpose as additional fertilizer salts will be
solubilized. A related problem that is often
associated with high soluble salt levels is
blossom end rot. Blossom end rot occurs
when there is a lack of calcium in fruit
tissue. Because calcium moves with water
in the transpiration stream, anything which
stresses roots and impedes water uptake
will also limit calcium uptake, including too
much water, too little water or high soluble
salts. Another problem we've seen on
tomatoes in West Central Florida this
season which is also related to the weather
is a phenomenon termed physiological leaf
roll. Under conditions which maximize
photosynthesis (i.e. warm, very sunny
days), excess carbohydrates build up in
leaf tissue and cause the plants to become
somewhat leathery, and leaves roll upward.
Although normally seen on older, lower
leaves, in a few cases leaf roll has been
severe with the entire plant affected. This
condition can be exacerbated by excess
fertilizer, high N rates and also seems to be
worse in plants that have undergone heavy
pruning. Usually, it does not cause too
much problem with yield and quality. One
exception might be some sunburning of
exposed fruit on severely affected plants.
It's hot, dry seasons like this one
which can show just how efficient or
inefficient your irrigation system is! An
easy, inexpensive way to check your
system before it becomes critical is to sign
up for the NRCS Mobile Irrigation Lab
(MIL). Following on-site evaluations of
irrigation systems, MIL technicians work
with owners or operators to develop
irrigation water management plans tailored
to their individual needs. To find out if this
free service is available in your area or to sign
up, contact your local NRCS office.
(P. Gilreath, Vegetarian 05-99)
Pumpkin Variety Trial, Fall 1998
Decorative or carving type pumpkins
are a relatively minor crop in Florida but in
recent years interest for direct sale and local
shipment has increased because of high
markets. Spring production in Florida is not
desirable due to the lengthy and expensive
storage time to keep them until the fall
marketing season. Optimum planting time
would be from late June to mid July and will
mature in late September to early October.
Because of the high temperatures and long
days during the early part of the growing
season fruit will mature in as little as 70 days
from seeding. They can be grown both as a
main crop or as a double crop behind a spring
The objective of this trial was to
evaluate the performance of decorative or
carving type pumpkin varieties under north
Production was on white on black
polyethylene mulched beds. Prior to applying
mulch beds were fumigated with 400 Ibs/A of
98:2 methyl bromide. Total fertilization was
146-45-146 Ibs/A of N-P20O-K2O. Irrigation
was with a single tube placed 6 inches from
the center of the bed and 1 inch deep.
Between row spacing was 8 feet and in-row
spacing was 40 inches. Twelve entries were
direct seeded on 6 August 1998. Design
was a random complete block with 4
replications. Registered pesticides were
applied on a weekly basis to control insect
First harvest was made 68 days after
seeding on 13 October 1998. At least 4 fruit
from each plot were rated for rind color and
height and diameter were recorded. Only
VEGEARIA NEWLETTR AMat, 1999
marketable fruit were weighed and data
Total yields ranged from 247 cwt/A
for 'Aspen' to 98 cwt/A for 'Gold Rush'
(Table 1). 'Magic', 'Howden',
'Appalachian', 'Jumpin' Jack' and
'Connecticut Field' produced similar yields
to 'Aspen'. The highest yielding entries
also produced the most fruit/a. The largest
fruit was produced by 'Gold Rush' at 16.2
Ibs and was significantly higher than all
other entries. Smallest fruit was produced
by 'Wizard' at 8.5 Ibs. The tallest fruit was
produced by 'Jumpin' Jack' with a
height/width ratio of 1.13 but was not
different from 7 other entries. Fruit of 'Long
Face' had the deepest orange color but
were not different from 8 other entries. The
top 4 entries, 'Aspen', 'Magic', 'Howden'
and 'Appalachian' all produced good yields,
had fruit of good deep orange color and
height/width ratios of nearly 1 and should
be considered for commercial trial in North
Florida. Of these 'Howden is open-
pollinated and the rest are hybrids.
(Olson, Vegetarian 05-99)
Request for Pesticide Needs
The IR-4 program is a cooperative
government-industry project to support the
registration of pesticides and biological
pest control agents on minor crops. At the
present time, a large number of the
pesticides cleared on vegetables have
labels due to the IR-4 program.
Each year scientists, grower
representatives and industry
representatives meet to prioritize projects
that will be carried out the next years.
Florida priorities need to be included
and represented in the prioritization
process. The national prioritization
meeting is to be held the last of August this
I am asking for two things: 1. That high
priority pest control needs be sent to me; and
2. Requests for clearance of specific
pesticides for a major pest in a specific minor
crop or "crop group" be sent to me. I will
compile these and send them to Charles
Meister, southern region IR-4 coordinator to
give to specific Florida representatives at the
For the high priority pest control needs
items, there may or may not be a pesticide
available to control the pest. For example a
high priority need may be to control wild
radish in Chinese cabbage. I do not know of
a herbicide that will control wild radish in cole
crops at the present time. But, if work done in
other areas show that a specific herbicide has
a tolerance on cabbage, etc. and will control
wild radish, then Florida will add their backing
to develop a tolerance for the whole Brassica
Leafy Vegetable group.
To submit a clearance request, we will
need certain additional information.
1. Pesticide (common name/manufacturer)
2. Commodity use site, etc.
3. Target Pests/potential effects
4. Why is this use needed?
5. Is there supporting data available
(phytotoxicity, efficacy, yield, etc.)
The use needed part is important in
that other pesticides for control of the pest
may be labeled, but not be effective. If so,
Supporting data now is also important.
Efficacy of an insecticide against an insect on
another or similar crop can be used.
VEGEA~iN NWSLTTE Ma199
Please mail, fax or e-mail
information to me in time to put this
together for the meeting.
Send to: WM Stall, PO Box 110690,
Gainesville, FL 32611; Fax (352) 392-5653;
The malanga he brought to the south Florida
Fair in January, 1999 weighed a whopping 29
Ibs andl5 oz., breaking his old record of 18
Ibs and 3 oz. by 11 Ibs and 12 oz.
(Stall, Vegetarian 05-99)
Florida Record-size Vegetables
Through May 1999
The following is a listing of the current
record-holders for vegetables grown in
Florida. One new record was set in 98-99.
It was an up-grade of an older record set by
Ozaki in Palm Beach County.
Florida Record-size Vegetables
J. M. Stephens -Vegetable Crops Specialist
University of Florida 392-2134 ext. 209
Early Round Dutch
9 1/2 inches
8 Ib. 1 oz.
12 lb. 10 oz.
5 Ib. 4 oz.
20 lb. 9 oz.
29 lb. 8 oz.
3 Ib. 1 oz.
11 lb. 6 oz.
15 lb. 6 oz.
1 lb. 3 oz.
13 ft. 3 in.
2 lb. 6 oz.
4 Ib. 7 oz.
4 Ib. 8 oz.
1 Ib. 8 oz.
11 Ibs. 2 oz.
21 Ib, 8 oz.
19 lb. 8 oz.
29 Ib. 15 oz.
80 lbs. 13 oz.
VEGEARIN NESLETERMat, 1999
Okra, pod (wt)
Okra, pod (length)
La. Green Velvet
11 lbs. 13 oz.
22 1/4 in.
3 lb. 11 oz.
1 lb. 1 oz.
2 lb. 13 oz.
30 lb. 3 oz.
3 lb. 12 oz.
23 Ib. 5 oz.
36 Ibs. 8 oz.
131 lb. 12oz.
23 lb. 12 oz.
3 Ib. 11 oz.
47 Ib. 9 oz.
11 lb. 11 oz.
6 lb. 2 oz.
18 Ib. 4 oz.
12 Ib. 15 oz.
Prepared by Extension Vegetable Crops Specialists
Dr. D. J. Cantliffe
Dr. D. N. Maynard
Dr. W. M. Stall
Dr. T. E. Crocker
Dr. S. M. Olson
Mr. J. M. Stephens
Dr. G. J. Hochmuth
Dr. S. A. Sargent
Dr. C. S. Vavrina