Title: Vegetarian
Full Citation
Permanent Link: http://ufdc.ufl.edu/UF00087399/00255
 Material Information
Title: Vegetarian
Series Title: Vegetarian
Physical Description: Serial
Creator: Horticultural Sciences Department, Institute of Food and Agricultural Sciences, University of Florida
Publisher: Horticultural Sciences Department, Institute of Food and Agricultural Sciences, University of Florida
Horticultural Sciences Department
Publication Date: April 1990
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Bibliographic ID: UF00087399
Volume ID: VID00255
Source Institution: University of Florida
Rights Management: All rights reserved by the source institution and holding location.


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A Vegetable Crops Extension Publication

Vcgctablc Crops Department 1255 HlSDD* Gaincsvillo, FL 32611 Telephonic 392-2134

Vegetarian 90-04



A, Calendar

B. Florida Weed Tour

C. New Publications


A. Principles of Liming Soils.

B. Managing Thrips and Tomato

April 13, 1990

Spotted Wilt Virus in

h I C. National Stand Establishment Conference April 4-6.


SlA. The Fifield Hall Organic Gardening Theme Park.

Note: Anyone is free to use the information in this newsletter.
~ Whenever possible, please give credit to the authors. The purpose of
S*trade names in this publication is solely for the purpose of providing
: information and does not necessarily constitute a recommendation of
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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,
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A. Calendar.

May 2 3, 1990. Florida Weed
Tour. (Contact W. M. Stall or Joan

Saturday, June 9, 1990. Live Oak
Vegetable and Fruit Crops Field Day,
8:30 AM 12:00 Noon, Live Oak AREC.
(Contact Bob or George Hochmuth or Tim

June 11-15, 1990.
Horticulture Institute, Camp Ocala.
(Contact Jim Stephens).


July 9 August 25, 1990.
Vegetable Crop Production and Marketing.
International USDA Technical Course TC
130-11. (Contact Steve Sargent).

B. Florida Weed Tour.

The annual Florida Weed Tour will
be held May 2 and 3, 1990. The tour will
start at the Horticulture Unit, 7002 N. W.
71 St., Gainesville at 8:30 AM. Weed
control plots in sweet corn, watermelon,
cucumbers, squash, snap beans, southern
peas, pepper, eggplant, cabbage, napa, bok
choy will be toured.
In the afternoon of the 2nd the
tour will continue at Zellwood with trials
in lettuce, several leaf crops, cabbage,
napa, bok choy and carrots on the muck.
An industry sponsored dinner will follow
that evening. On May third the tour will
begin in Belle Glade in the afternoon
with a tour of lettuce, several leaf crops,
celery and carrots.
For more information contact
W. M. Stall or Joan Dusky.

C. New Publications.

F. M. Rhoads and S. M. Olson.
1990. Toxicity in Plants Due to Copper
from Pesticides in Tomato Field Soils.
NFREC Res. Rept. 90-2.

S. M. Olson and J. M. Snell. 1990.
Cantaloupe Variety Evaluation 1982-1988.
NFREC Res. Rept. 90-4.

S. M. Olson and J. M. Snell. 1990.
Broccoli Variety Evaluation 1981-1989.
NFREC Res. Rept. 90-5.

S. M. Olson and J. M. Snell. 1990.
Collard Variety Evaluation 1982-1988.
NFREC Res. Rept. 90-8.

S. M. Olson and J. M. Snell. 1990.
Tomato Variety Evaluation 1982-1988.
NFREC Res. Rept. 90-10.

S. M. Olson and J. M.
Onion Variety Evaluation
NFREC Res. Rept. 90-11.

Snell. 1990.

C. Vavrina, Editor. The
Proceedings of the Tomato Workshop and
Field Day SWFREC Rept. No. IMM90-5.


A. Principles of Liming Soils.

Most vegetable growers are aware
of the need to lime acidic soils to produce
optimum yields and quality. However,
there is often confusion about the basic
purpose of liming and about how to
determine when and how much lime to
apply. The purpose of this article is to
explain the effects of soil acidity and give
guidelines for correcting these infertile
Soil acidity (or alkalinity) is
measured on a logarithmic (pH) scale that
ranges from 0 to 14 with 7 being neutral.
Soil pH values below 7 are acidic and
those above 7 represent alkaline soil
conditions. Each change of one unit of
the scale represents a 10-fold increase (or
decrease) in the intensity of acidity or
Soil pH measures the activity of
hydrogen ions (Ht) in the soil. It is
important to measure H' since H ions
affect many chemical and biological
reactions in the soil and thus affect the

performance of our vegetable crops. Most
vegetables perform well in a soil pH range
of 5.5 to 6.5. Liming soils to pH levels
above 6.5 is rarely justified and may even
cause reductions in yield.
It was once thought that the
negative effects of acid soils on crop
growth were due to the high
concentration of H ions. However, plants
can grow well in nutrient solutions of pH
4.5. The H ion concentration has no
direct negative effect on plants until the
pH falls to levels probably below 4.0. The
poor crop performance in acidic soils is
due more to toxic effects of metals such
as aluminum or manganese (which are
more soluble in acidic conditions) or to
nutrient deficiencies of calcium,
magnesium, potassium, or phosphorus.
Liming acid soils, therefore, should
be targeted at neutralizing toxic elements
such as aluminum or manganese. In very
sandy soils, aluminum concentrations are
usually low so that manganese solubility
is often the major problem. However,
manganese is an essential element for
plants so one does not want to increase
the pH too high (above 6.5) which would
make manganese unavailable to plants.
The amount of lime to use to
correct soil acidity should be estimated by
a well-calibrated lime-requirement test.
The soil reaction (pH) can be measured
easily by a water extract of the soil but
this measurement only reflects what is
called "active acidity." There are still
unmeasured H ions on the soil particles.
These must be measured and accounted
for in a good liming program because they
could come into play at sometime during
the growing season. Depending on the
particular soil testing laboratory, various
buffer solutions will be used to estimate
this "reserve" acidity.
The choice of liming material
depends on several factors including cost,
quality, particle size, availability, relative
ability to neutralize acidity, and nutrient-
supplying capability. Most liming
materials, in addition to neutralizing soil
acidity, can supply calcium and/or
magnesium. Testing soils for magnesium
supplying capability can help in choosing

a liming material. For example, if a soil
needed a pH increase and needed
magnesium, then dolomite might be
preferable over calcitic lime. Both
dolomite and calcitic limestone supply
calcium. Gypsum (calcium sulfate)
supplies calcium but it is not a liming
material and will not neutralize acidity.
Adjusting soil pH to the range of
5.5 to 6.5 has several benefits for
vegetable producers. Supplying calcium
and magnesium, and reducing metal
toxicities have already been mentioned.
However there are other benefits to
liming acidic soils.
Plant nutrient availability is
generally better in soils with a pH in the
range of 5.5 to 6.5. Phosphorus,
potassium, calcium, magnesium, and
ammoniacal nitrogen utilization is better
when acidic soils are limed to pH range of
5.5 to 6.5. Liming to levels above this
range can have deleterious effects
because the availability of nutrients,
especially micronutrients such as
manganese and zinc can be reduced under
alkaline conditions.
Acidic soils also can restrict the
activity of certain beneficial soil
microorganisms such as the nitrifying
bacteria that convert ammoniacal nitrogen
to nitrate nitrogen. Liming acidic soils
provides a more favorable environment for
these organisms. The Fusarium wilt
organism of tomato is inhibited by
increasing the soil pH. Pushing the pH
to 6.5 might be recommended here, even
though the crop itself would do well at
6.0 in the absence of the disease
Liming acidic soils is not a simple
nor routine practice. There are many
considerations that must go into a sound
liming program. Liming must be based
on solid justifications and on a well-
calibrated lime requirement test. There
are still too many instances where
growers routinely lime soils without
regard to real need (or lack of need). It
is possible that this practice is costing
those growers in terms of reduced yields
and increased fertilizer needs.
(Hochmuth, Vegetarian 90-04)

B. Managing Thrips and
Tomato Spotted Wilt Virus in Tomatoes.

Thrips in the genera Frankliniella
and Thrips are pests of many crops
worldwide. Economic damage can occur
from feeding and egg laying activities that
result in injury to leaves, flowers, or fruit.
Direct injury from thrips causes serious
economic losses to numerous agronomic,
fruit, vegetable, and ornamental crops.
Western flower thrips (Frankliniella
occidentalis) were first noted in North
Florida in tomatoes in the spring of 1985.
A severe form of cosmetic fruit damage
was noted on spring tomatoes in North
Florida during that year. Subsequent
research was conducted in our laboratory
to determine the cause of the damage.
Three species of thrips were placed on
tomato blooms, including western flower
thrips, tobacco thrips (F. fusca), and
eastern flower thrips (F tritici). The
results of the study revealed that western
flower thrips females are responsible for
the cosmetic fruit damage occurring in
tomato in North Florida. The damage
occurred when either small fruit or
flowers were infested. The other species
of thrips did not cause any cosmetic fruit
damage. The mechanism by which
western flower thrips damaged the fruit
was also investigated. Individual eggs and
immatures were observed in the center of
scars on damaged fruit. Immature thrips
also occurred on damaged fruit several
days after adults were removed. These
observations demonstrate that the damage
is caused by western flower thrips egg
laying into small fruit. There are reports
that western flower thrips populations are
very high this spring in tomatoes and
peppers in South Florida and that
cosmetic fruit damage is heavy in some
fields. This is the first time that heavy
damage has been reported in South
Florida, which undoubtedly is related to
movement of western flower thrips into
the region.
Western flower thrips also vectors
of tomato spotted wilt virus (TSWV).
Other species of thrips that are vectors of
TSWV in Florida are tobacco thrips and

onion thrips (rips tabaci). This disease
was first noted in North Florida in
tomatoes in the spring of 1986 and has
now become a major disease problem in
tomatoes and other crops in North
Florida. It has recently been found in
tomatoes in South Florida production
Studies were conducted in North
Florida to determine the seasonal
abundance of thrips in North Florida
tomatoes during 1987, 1988, and 1989.
The results for each spring cropping
season are shown in Figure 1. Few were
collected in each fall cropping season;
therefore, the data are not shown. Adult
thrips accounted for about 88% of the
total thrips collected in the tomato
flowers during the three years of the
study. About 97% of these adults were
western flower thrips, tobacco thrips, or
eastern flower thrips. Populations of each
species were greatest from late April to
early June each year, with greatest
population densities in May. Each species
was found to prefer only the tomato
flowers, although insecticides used to
control other insects may have reduced
any populations on other plant structures.
Other studies were conducted to
develop a sampling method to estimate
density for scouting programs. Time of
day when sampling did not influence
sample estimates. However, densities of
thrips in tomato blooms sometimes
differed in marginal and nonmarginal
areas of fields. Also, thrips densities were
greater for blooms located on the upper
half of tomato plants compared with
blooms on the lower half of tomato plants.
Other studies were conducted to
determine economic thresholds of thrips
in tomato blooms by determining the
relationship between density and the
amount of cosmetic fruit damage.
Management of thrips in tomatoes
is greatly complicated by several factors.
One is their vector potential for TSWV.
Insecticides sprayed to control adult thrips
moving into tomato fields will not prevent
their transmission of TSWV. However, it
is believed that control of immature
thrips will reduce spread of virus from


plant to plant within a field. A second
problem is identification of thrips. A
sampler can not reliably identify thrips
while in the field. All species of thrips
can not transmit the TSWV and only
western flower thrips are known to cause
cosmetic fruit damage. Therefore, some
species are not economically important
and control of these species is not
necessary. A third problem relates to
control of thrips with insecticides. Only
one insecticide (Monitor) is known to
provide good control of thrips in tomatoes
and this product is limited by label
instructions in the number of applications
during the season. Steve Olson and I are
conducting an experiment to determine if
other insecticides labeled on tomatoes will
provide control, but results will not be
available for this upcoming field season.
Based on our current research
findings, we are able to suggest some
management procedures. Control
activities should be focused most
intensively from late April to early June.
Fields during this period should be
sampled twice per week. At other times
(including the entire fall cropping season),
samples to estimate density should be
taken once per week. On each sample
date, the presence or absence of thrips in
individual blooms should be determined
for 15 to 20 randomly selected blooms in
both marginal and nonmarginal areas of
each field. All samples should be taken
from blooms located on the upper half of
tomato plants. Control of thrips is not
necessary if less than one third of the
blooms are inhabited by thrips. Because
of the mass movement of adults into
fields from late April to early June and
the difficulty of control with insecticides,
it may be difficult to keep thrips densities
below this threshold and some losses from
TSWV and direct cosmetic fruit damage
may still occur. But, these management
procedures should prevent avoidable
economic losses.

(Joe Funderburk and Steve Olson
Vegetarian 90-04)

Mean number of adult F. occidentalis, F.
tritici, and F. fusca per flower in tomato
fields sampled weekly during the spring of
1987, 1988, and 1989 in Gadsden County,

F. fusca 1987
-- F. occidentalia
---- F. tritici

1- n,


C. National Stand
Establishment Conference April 4-6.

During the first week of April, 80
scientists representing 15 states and 5
countries met in Minneapolis, Minnesota
for the National Symposium on Stand
Establishment for Horticultural Crops.
The conference was designed to present
research specifically in the areas of stand
establishment, seed quality, seed priming,
seedling emergence, biological and
agrochemical seed treatments, and
transplant production.
Florida was represented by two of
Dr. Cantliffe's graduate students, Carlos
Parera, and Daniel Leskovar and
Extension Vegetable Specialist, Charles S.
Vavrina. Parera presented a paper
entitled "Improved Stand Establishment of
sh2 Sweet Corn by Solid Matrix Priming
and Seed Disinfection Treatments." He
concluded that solid matrix priming and
sodium hypochlorite (bleach) improved
seedling emergence and stand
establishment and worked as well as
standard chemical seed treatments.
Leskovar presented "Tomato Fruit
Yield and Seedling Growth in Response to
Transplant Packing and Storage." The
main emphasis of this work was to
determine if any differences occurred
between transplants that arrived in the
field in the tray (standard in Florida) and
those that were pulled and boxed
(standard in northern markets). He found
a 65% and a 75% increase in extra-large
fruit at first and second harvest
respectively, when transplants arrived at
the field in the trays. Total marketable
fruit yield was not affected by treatment
Vavrina presented "Performance of
Plant Growth Regulators on Tomato
Transplants and Subsequent Field
Production." Since Alar (Union Carbide)
has been discontinued for use in tomato
seedlings, other growth regulators were
tested, however, none of the materials
tested are registered for use in tomatoes
(Sumagic Valent, Cultar ICI, BAS 111 -
BASF, Tilt Ciba-Geigy). All provided
adequate reduction in tomato seedling

growth in the transplant house. Field
results indicate high rates of the
compounds could reduce average fruit
weight and yield, particularly of extra-
large fruit. Tilt and BAS 111 treatments
were more forgiving with respect to
excesses in rate.
The next conference is scheduled
for late February 1992 in south Florida,
probably in Ft. Myers or Naples. Please
hold a spot on your calendar and ready
those research and demonstration studies
for presentation we want to be well

(Vavrina, Vegetarian 90-04)

A. The Fifield Hall Organic
Gardening Theme Park.

By now many of you have heard
that the Vegetable Crops Department has
dedicated the student gardens area across
Hull Road from Fifield Hall toward the
establishment of an organic gardening
theme park. The project got underway
about the first of February with the
completion of a master plan.
The project has 4 basic purposes:
1) serve as a teaching laboratory for
college courses in vegetable crops; 2)
allow us and other educators to
familiarize ourselves with various "organic"
products and practices; 3) help us
demonstrate best organic techniques to
county agents, vo-ag teachers, Duval
County Urban Gardening staff members,
Florida Master Gardeners, University
affiliates, and others who work in public
education; and 4) to generate some
needed information through observational
studies and applied research.
Keep in mind that the focus of the
theme park is on organic gardening,
rather than organic farming. However, it
is anticipated that much of what is
learned here can be applied to the
production of organically grown vegetables
for sale.
The plan includes zones set aside
for certain purposes. While the total area


includes about 4 acres, about 1 acre is
already occupied by research greenhouses
and support facilities. The remainder
consists of approximately 2 1/2 acres of
open field surrounded by mowed grass,
trees, and buildings for storage and
support (such as cold frames for
transplant growing).
Zone A will include all operations
of an "organic" nature. In Zone B, the
use of chemical fertilizers and pesticides
will be allowed, for comparison purposes.
Zones A and B will be separated by a 100
foot buffer zone (chemical free area).
Establishing the park has been a
slow process. With a tight budget and
limited labor, we are accumulating raw
materials, building fences, putting in
irrigation, and constructing grow-boxes.
Our stockpile of organic fertilizer
materials, soil amendments, and mulches
has grown daily. Even so, we have been
able to get some individual plant growing
projects underway.
To date the following studies
and/or demonstrations have been
established as of April 1, 1990:

a) Model organic garden (50'x50') -
several varieties of vegetables have been
planted utilizing sheep manure on one
half and chicken manure on the other

b) Model chemical garden (50'x50') -
using chemical fertilizer and to be sprayed
as needed.

c) Model chemical fertilizer garden
(50'x50') using chemical fertilizer but no

d) Demonstration of Fertrell (blended
organic fertilizer) at two rates with
several vegetable varieties.

e) Demonstration of agraferm (composted
fertilizer) at two rates with several
vegetable varieties.

g) Replicated study of commonly used
"organic" pesticides on several garden

h) Other studies/demonstrations
anticipated include: composted yard
waste, municipal waste, raw yard waste.
crabwaste, mushroom compost, other
animal manures, mulching, and a variety
of alternatives to synthetic chemical
Future We advise all agents to
keep on the look-out for new
developments here at the organic theme
park. We will try to keep you posted so
that you can visit the site personally or
bring your Master Gardeners or other
targeted clientele at the opportune time.
Hopefully, we will have planned field days
once the park is smoothly running.
Coordinators Leadership for the
project is provided by Dr. Steve
Kostewicz, Associate Professor of
Vegetable Crops, and Jim Stephens,
Extension Vegetable Crops Specialist. We
have employed Victor Heidman to assist
in the project. The entomology study
underway is the work of Don Short and
his assistant Paul Ruppert.

(Stephens, Vegetarian 90-04)

Prepared by Extension Vegetable Crops Specialists

Dr. D. J. Cantliffe

Dr. D. N. Maynard

Dr. W. M. Stall

Dr. G. J. Hochmuth
Assoc. Professor

Dr. S. M. Olson
Assoc. Professor

Mr. J. M. Stephens

Dr. J. M. White
Assoc. Professor

Dr. S. A.Sarg t
Asst. Professor (Editor)

Dr. C. S. Vavrina
Asst. Professor

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