INSTITUTE OF FOOD AND
UNIVERSITY OF FLORIDA
A Vegetable Crops Extension Publication
bgetable Crops Department 1255 HSPP Gainesville, FL 32611 Telephoic 392-2134
March 15, 1990
I. NOTES OF INTEREST
B. New Publications
II. COMMERCIAL VEGETABLES
A. Changes in ESTL Computer-Printed
Vegetable Soil Tests.
B. Geminivirus Subcommittee Meeting.
C. National Pepper Conference Meeting in Delaware.
D. Timing of Vegetable Production.
E. Increased Use of Modified Atmospheres
S IIII. VEGETABLE GARDENING
S^A. Revised Vegetable Gardening Guide.
Note: Anyone is free to use the information in this newsletter.
J:,7 Whenever possible, please give credit to the authors. The purpose of
trade names in this publication is solely for the purpose of providing
information and does not necessarily constitute a recommendation of
The Institute of Food and Agricultural Sciences is an Equal Employment Opportunity Affirmative Action Employer authorized to provide research,
educational information and other services only to individuals and institutions that function without regard to race, color, sex, or national origin.
rTrnDEDATI\Ic cYTKlCNiAl UAtrn r I k AntPOIPI TII IC A iKr untitCe cr~Mnlfirl' RSTATF nlF FI flRlilA IFAq I INIVFRRITY OF
I. NOTES OF INTEREST
April 20, 1990.
Union, UF, Gainesville.
B. New Publications.
Cir. 104-Q, Vegetable Gardening
Guide (Revised Feb., 1990). (Contact Chic
Hinton, IFAS Publications for copies).
II. COMMERCIAL VEGETABLES
A. Changes in ESTL Computer-
Printed Results for Vegetable Soil Tests.
During the last week of February,
changes were made in the ESTL program
that prints out soil-test results and
fertilizer recommendations for vegetables.
The changes involve three major areas.
First of all you will note that the
calibration chart has changed. What we
call low, medium, and high has changed
due to the re-calibration efforts of Ed
Hanlon and myself regarding the Mehlich-
I soil-test extractant. The change in the
computer print-out reflects the
recalibration. More details on this are
available from Notes in Soil Science No.
38 (SS-SOS-907) "IFAS Standardized
Fertilization Recommendations for
The second change involves the
actual fertilizer recommendations. The
most important point here is that there
will no longer be a fertilizer
recommendation provided for soils that
test high or very high in P or K.
Previously, high testing soils received an
third change involves the
The set of footnotes that
the fertilizer recommendation
has been essentially re-written to contain
many more pointers and suggestions for
managing the recommended fertilizer.
These changes were made to
reflect the status of research on fertilizer
management and crop nutrient
requirements for vegetables in Florida. If
you have any questions, please contact
(Hochmuth, Vegetarian 90-03)
B. Geminivirus Subcommittee
Subcommittee (GVS) met February 1,
1990 in Homestead during the workshop
on "Sweetpotato Whitefly-Mediated
Vegetable Disorders in Florida".
Subcommittee members include Dr. Agrios
(Chairman), Dr. Emino, Dr. Hiebert, Dr.
Mellinger (Glades Crop Care), Mr. Tim
Nance (Gulf Coast Tomato Growers), Dr.
Powell, Dr. Purcifull, Dr. Schuster, Dr.
Simone, Dr. Stansly, Dr. Stoffella, and Dr.
The GVS was made aware that
geminivirus-like symptoms have been
reported on Hibiscus and greenhouse
cucumbers to date. Pepper geminivirus
diagnosis may present special problems,
because symptoms similar to Tomato
Necrotic Dwarf Virus, also whitefly
transmitted, have been observed in
tomatoes. It was generally accepted that
several other whitefly transmitted viruses
now in the Western Hemisphere will
sooner or later be in Florida.
Short-term approaches approved by
the GVS include: a color fact sheet on
the geminiviruses and other whitefly
transmitted viruses in vegetables
(publication insured by Deans Woeste and
Davidson), an additional biological scientist
to be funded in the Plant Disease Clinic
to help process the mounting number of
samples, development of diagnostic DNA
and serological probes to these viruses
under the direction of Dr. Hiebert, a
postdoc to assist Dr. Hiebert in probe
development and an OPS person to run
the probes once developed.
Ongoing efforts in 1990 will
include: probe development (Hiebert),
monoclonal antibody testing and virus
epidemiology (Powell), ornamental
geminivirus survey (Zettler), electron
microscope virus characterization
(Purcifull), whitefly management and
virus transmission studies (Schuster and
Stansly), pepper whitefly management
(Webb), virus exclusion in transplant
production and tomato yield assessment
(Vavrina), and tomato breeding for virus
resistance (Scott). Industry interfacing
efforts by Dr. Mellinger will provide a
data base of geminivirus incidence and
progression from over 3,000 acres of
vegetables. And Tim Nance offered Gulf
Coast Tomato Grower fields for sites of
data accumulation by IFAS scientists.
The next meeting of the GVS is May 2,
1990 in Bradenton.
(Vavrina, Vegetarian 90-03)
Meeting in Delaware.
I Pepper Conference
The University of Delaware is
hosting the 1990 National Pepper
Conference in Wilmington, Delaware on
July 25-27, 1990. The meeting will
include research paper presentations and
tours of Delaware and New Jersey
vegetable production areas. Registration
is $75.00 before June 1, 1990 and includes
proceedings, 3 lunches, buffet dinner and
If anyone would like information, I
can supply all the necessary forms. If
anyone would like to present a paper at
the meeting, I can provide you with the
form or you can call Mr. Ed Kee at 302-
856-7303. Some of our county faculty and
pepper growers have attended this
meeting in the past and have benefitted
(Hochmuth, Vegetarian 90-03)
Timing of Vegetable
It is sometimes useful to time
vegetable production to take advantage of
market windows for a particular vegetable.
At other times it is critical to time the
production of a certain vegetable, for
example, jack-o-lantern pumpkin for the
season of the
factors, including variety,
year, and location in the
timing of vegetable
Data provided by T. K Howe at
the Gulf Coast Research and Education
Center in Bradenton for the spring 1989
tomato variety trial illustrates the effects
of variety on timing. 'Duke' and 'Bingo'
produced about 62% of their crop in the
first harvest, whereas 'Solar Set' and
'Bonita' produced only about 42% of their
crop at first harvest.
The effect of season on timing is
illustrated in data developed on slicing
cucumber at the Central Florida Research
and Education Center at Leesburg by G.
W. Elmstrom. Spring crops required from
37 to 67 days with an average of 57 days
from seeding to first harvest. On the
other hand, fall crops required from 40 to
50 days with an average of 45 days from
seeding to first harvest. Because of good
growing conditions early in the season,
fall vegetables usually mature quicker
than spring-planted vegetables.
Location in the state has an
appreciable effect on time from
transplanting to first harvest of the spring
crop as indicated in Table 1.
Table 1. Days from tomato transplanting
to first harvest for spring crops at four
locations in Florida.
Both the range in days and average
number of days from transplanting
decrease from south to north in the state.
The fewer days from transplanting to first
harvest is related to later planting and
the associated longer days and better
Within the constraints of weather,
most frequently the threat of frost at the
beginning of the spring season and end of
the fall season and summer rains at the
end of the spring season and beginning of
the fall season, it is possible to time
harvests with a fair degree of accuracy.
But, growers aiming for a particular
market or market window must keep
precise records in order to fine tune the
timing of their crops to take advantage of
(Maynard, Vegetarian 90-03)
Increased Use of Modified
for Shinnina Florida
A significant number of shippers in
the Plant City area have begun using
modified atmosphere treatments for
shipping strawberries this season. Since
last season there has been a six-fold
increase from 2 to 12 shippers employing
this procedure. The system currently
being used is called Tectrol Atmospheres
and is manufactured by Transfresh Corp.,
Salinas, CA. Over 50% of all strawberries
shipped from California are treated with
this system or another type of modified
Strawberries are quite perishable,
being especially susceptible to mechanical
injury during harvest and handling, and
water loss and decay during shipping. For
these reasons, several years ago Florida
growers in this area converted to the use
of standard cartons which are palletized in
the field to minimize injury and which
facilitate forced-air precooling. After
transport to the shipper the berries are
rapidly precooled to about 35F to remove
field heat and reduce the potential for
water loss and decay during shipping.
The shipping life of strawberries
can be extended by several days through
the use of controlled or modified
atmospheres in the storage environment.
These procedures utilize low oxygen
concentrations in conjunction with
refrigeration to slow the respiration rate
of the crop being stored, thus extending
shipping life. For many crops elevated
levels of carbon dioxide suppress growth
of decay pathogens. Controlled
atmosphere (CA) storage, as the name
implies, involves constant control of the
atmosphere in order to maintain the
desired gas mixture in the storage
environment. Modified atmosphere
storage (MA) is achieved by a single
injection of a desired gas mixture into a
gas-tight room, a refrigerated trailer or an
overwrapped pallet, which is how the
Tectrol system works. MA can also be
achieved by allowing the respiration of
the product to lower oxygen and raise
carbon dioxide concentrations; this
method is more often used for consumer
In 1988 we studied the effect of
carbon dioxide levels on six fungal
pathogens associated with Florida-grown
strawberries (C. Ragland, J.A. Bartz, J.K.
Brecht and S.A. Sargent). The inhibitory
effects of storage at 50 and 20% CO2 on
fungal growth were equal for
Dendrophoma obscurans, Colletotrichum
acutatum, C. Fragarieae, Glomerella
cingulata and Alternaria tenuissima.
Botrvtis cineria was controlled equally at
50* and 680 with 20% CO,.
The use of MA-treated pallets has
been well-received by buyers. Although
the added benefits of MA and CA are
minimal for strawberry shipments to local
markets, both show potential for
increasing shipping life of strawberries in
order to reach distant markets in the U.S.
and Canada and for exports.
(Sargent, Vegetarian 90-03)
III. VEGETABLE GARDENING
Extension Circular 104-Q, revised
February 1990, is now off the press and
available through normal channels. Some
16,000 copies were printed at a cost of
10.9 cents per copy. County orders
should have been submitted with last
year's county plans of work, so hopefully
each county will shortly receive the
number of copies requested.
A number of major and minor
changes were made in the 1990 edition.
Of course, my colleagues in the pest and
soils management disciplines updated
their respective sections and are listed as
co-authors. My thanks to Bob Dunn,
Extension Nematologist; Jerry Kidder,
Extension Soils Specialist; Don Short,
Extension Entomologist; and Gary
Simone, Extension Plant Pathologist, for
their inputs with this circular. If any of
you readers have questions about their
particular segments, please contact them
One new item in the guide was a
section giving directions for making back-
yard compost, as follows: Compost as a
home garden composer you can reduce
the amount of yard waste going to land-
fills, while manufacturing your own
compost. Composting is easy, and yields
a manure-like organic fertilizer/soil
conditioner highly beneficial on Florida's
infertile native soils. A small compost
pile measuring 3'x3'x3' (1 cu. yd), called a
compost unit, is easily made.
.Construct a bin with sides made
from treated lumber, concrete blocks, wire
or other durable materials.
.Make successive 12-inch thick
layers of plant waste such as leaves, lawn
clippings, shredded branches, and wood
.Onto each layer, distribute one
cup each of dolomite and 6-6-6 fertilizer.
.Moisten each layer, then keep the
After 3-4 weeks and every week
thereafter, thoroughly mix the compost
.Compost should be ready for use
in 2 to 12 months, or when plant parts
.Build larger piles by putting
together several units into a single bin."
Fungicides The use of the EBDC
fungicides proposed for banning has been
left in the recommendations, until current
stocks and labels are depleted.
Insecticides Insecticidal soap was added
to the suggested list for home gardeners.
The basic core of insecticides now
includes: B.t., carbaryl, malathion,
diazinon, soap, and baits of dylox or
Nematicides metam remains as the most
readily available effective material for
home soil fumigation.
Varieties Keep in mind that there are
space limitations to the list of varieties we
could include in the guide. The following
vegetable varieties were added to the list.
Sweet corn 'How Sweet It Is';
Cucumbers, slicers 'Pot Luck';
Eggplant -'Tycoon'; Okra -'Dwarf Green';
Pepper, sweet 'Cubanelle'; Pumpkin -
'Cushaw'; Summer squash 'Sundrops';
Tomato -'Solar Set', 'Sweet Chelsea',
'Sweet 100'; Seedless watermelon -
'Fummy'; Beets 'Cylindra'; Chinese
cabbage 'Napa'; Kohlrabi 'Grande
Duke'; Strawberry 'Tufts'.
New section added Plant family. This
section was added for each vegetable so
that gardeners can practice crop rotation.
They are encouraged to group family
members and avoid planting family
members following each other in
Crop comments in this new section,
brief considerations are outlined following
each vegetable. For example, after sweet
potatoes is stated," Convolvulaceae sweet
potato weevils are a serious problem.
Start with certified free transplants.
Use vine cuttings to prolong season."
In addition to the Vegetable
Gardening Guide, Cir. 104-Q, the Organic
Vegetable Gardening guide, Cir. 375A, has
been reprinted in sufficient quantity for
use in county programs.
(Stephens, Vegetarian 90-03)
Prepared by Extension Vegetable Crops Specialists
Dr. D. J. Cantliffe
Dr. D. N. Maynard
Dr. W. M. Stall
Dr. J. Hochmuth
Assoc. Professor (Editor)
Dr. S. M. Olson
Mr. J. M. Stephens
Dr. J. M. White
Dr. S. A. Sargent
Dr. C. S. Vavrina