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Title: Vegetarian
Series Title: Vegetarian
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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: December 1998
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Bibliographic ID: UF00087399
Volume ID: VID00343
Source Institution: University of Florida
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' UNIVERSITY OF Cooperative Extension Service

FLORIDA Institute of Food and Agricultural Sciences



VEGETARIAN


A Vegetable Crops Extension Publication
Horticultural Scicncca Department P.O. 110690 Caineavillc, FI 32611 Telephone (352)392-2134


Vegetarian 98-12


December 1998


CONTENTS


VEGETABLE CROPS CALENDAR


, ^
Soil Improvement with Organics

Demonstration of Cover Crop Sunn Hemp (Crotalaria
V/ juncea) Grown on Calcarious Soils in South Florida

Tomato Little Leaf Revisited

Scheduling Irrigation Using Tensiometers For Tomatoes
On A Calcareous Rocky soil


VEGETABLE GARDENING

Disease Resistant Tomato Varieties for the Home
Gardener


Note: Anyone is free to use the information in this newsletter. 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 product.

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, age, handicap or national origin.
-r I Ttnfrnl erflr Ir &Tr t e i TIMT fit TA I H urE5? c fflh~Trfd EOTATlr%*TI1T n 1nrA trAe Trhin?WcicivCCrc LB n TTVA


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V,








VEGETA RIAN NEWSLETTER N 1998


Vegetable Crops Calendar



January 9,1999. Suwannee Valley Field and
Greenhouse Grower's shortcourse and Trade Show
Contact Bob Hochmuth (904)362-1725.

March 8-12, 1999. Florida Postharvest
Horticulture Institute & Industry Tour. Contact
Steve Sargent (352) 392-1928 ext. 215.


Commercial Vegetables


Soil Improvement with Organics
Site selection is the first step when
planning to grow a crop. Good growing
conditions and good soil will compensate for
many poor management decisions. Selecting
a 'good' soil may not be an option, but there
are practices which will help improve the soil.
Helpful practices include crop rotation, use of
cover crops, green manure crops, animal
waste compost, plant material compost, and
combinations of these practices. Under
most Florida conditions, green manure crops
should be grown in the winter and summer and
plowed under well in advance of the spring and
fall crop planting seasons. Rye, rye grass,
wheat, and oats should be considered in the
winter and southerpea, millet, sudax,
sesbania, and hairy indigo in the summer. Be
sure to mow hairy indigo and sesbania before
they go to seed to reduce the risk of them
becoming a weed problem.
Adding compost to the soil has been
used over the years to improve water holding
ability, nutrients, cation exchange, and tilth.
This practice may not be practical on large
acreages. Most home gardeners incorporate
about 440 pounds of compost per 100 sq. ft. to
equal about 5% of the volume of the first foot
of soil. This translates to around 96.5 tons of
compost per acre. Granted, the compost
would improve the soil, assuming it is evenly
incorporated to a depth of one foot. The cost
and ability to spread and incorporate that
amount of compost at one time is a


green manure crops and adding compost in
lesser amounts over time will improve the soil and
could be the practical way to improve soil. The
central idea is to improve soil to the target amount
of 5% organic matter.

(J.M. White, Vegetarian 98-12)

Demonstration of Cover Crop Sunn Hemp
(Crotalaria juncea) Grown on Calcareous soils
in South Florida
Since summer of 1997, a group of
researchers from TREC in Homestead (Drs.
Herbert Bryan, Yuncong Li, Ranuka Rao), and
Teresa Olczyk, Miami-Dade Cooperative
Extension Service, are involved in evaluating
several summer cover crops for South Florida.
Summer cover crops evaluated were sunn hemp,
sorghum-Sudan, soybean, aeschynomene,
sunflower, cowpeas, peanut, and guar. After
initial trial in the summer 1997, sunn hemp was
selected as the best performing cover crop. Sunn
hemp seeds germinated very well, produced thick
ground cover, successfully suppressed weeds
and produced the highest amount of biomass
(7,700 Ib dry biomass per acre in three months
after planting). This cover crop also fixed about
180 lb of Nitrogen per acre.
In the summer of 1998, three larger field
demonstrations were conducted in the growers
fields in Homestead area. The objectives were to
introduce sunn hemp to the growers, collect
information on germination, growth, weed
suppression, insect and diseases presence, and
compare sunn hemp with Sorghum under typical
condition of commercial vegetable production.
Three vegetable fields were selected on
calcareous soils. Growers received 20 to 25 Ib
seeds of sunn hemp 'Tropic Sun', developed by
University of Hawaii. Seeds were donated by
S&M Farm supply in Homestead. Seed
germination rate was tested before planting.
Germination rate was 90%. Seeds were
inoculated with a cowpea strain before planting,
and planted with grain drills by growers on June
15, 1998 for grower #2, and June 17, 1998 for
growers #1 and 3. Sorghum was planted at the
same time in all three locations. All three fields
were disked before planting. No irrigation or
fertilizer was applied for either sunn hemp or
sorghum. Germination dates, growth and health


November 1998


~17ETA R1;4N NE~SLETTER








VI? E TAItIA NJWSLETERNovember 1998


received some irrigation from the avocado
grove near by, and sunn hemp germinated in
three days after planting. For non irrigated
fields it took two weeks to germinate, because
of very dry weather in late June.
Small numbers of whiteflies and thrips
were found on sunn hemp seedlings in early-
July. Limited numbers of stinkbugs and
cucumber beetles were noticed on mature
plants. At the same time sorghum plants were
heavily infested by armyworms. No worms
were found on the sunn hemp.


Three plots each from sunn hemp and
sorghum were selected for each site in the
beginning of August. Number of weeds and
cover crop plants were counted. Heights of sunn
hemp and sorghum plants were measured in the
field. Fresh weight of cover crop plants and
weeds were measured in the lab. Plants were
dried at 700C for 48 hours and dry weight was
recorded.
Two cover crop field days were organized,
on September 15 and October 9, 1998, and
above information was presented during field
days. Several growers expressed interest in
participating in the future demonstrations with
sunn hemp in the Homestead area.


Table 1. Average plant height, fresh weight, dry weight and population for two cover crops grown in
calcareous soil in Homestead (grower's fields), summer 1998.
Plant Field Plant height Fresh weight Dry weight Population Seeding
(inches) (Ibs/ac) (Ibs/ac) (# plants/ac) rate (Ibs/ac)
Sunn 1 44.9 24,502 6,687 75,2544 30
hemp
Sunn 2 51.5 33,156 7,025 372,495 36
hemp
Sunn 3 68.2 57,208 18,882 183,696 18
hemp
Sorghum 1 24.2 33,156 8,879 642,936 --
Sorghum 2 38.5 35,572 11,351 178,593
Sorghum 3 47.5 37,876 14,835 173,491

Table 2. Average fresh weight, dry weight and population of volunteer weeds in three demonstration
sites in Homestead (gower's field), summer 1998.
Weeds in: Field Fresh Weight (Ibs/a) Dry Weight (Ibs/a) Population of
Weeds/acre
Sunn Hemp 1 843 450 137,772

Sunn Hemp 2 6,968 1,180 464,343
Sunn Hemp 3 2,574 1,236 188,799
Sorghum 1 899 562 112,259
Sorghum 2 4,664 1,798 612,320
Sorghum 3 1,180 899 576,601


(Teresa Olczvk. Vegetarian 98-12)


VEGETARIAN NEWSLETTER


November 1998








VEGETARJANNEWSLETTER November 1998


Tomato Little Leaf Revisited

This is not a new problem but is one
that many people fail to identify in the field. It
is still showing up occasionally in Florida
tomato fields. I visited a tomato field in the
East Coast production area on 1 December of
this year to confirm the problem. Yields loses
ranged from 20 to 50% in affected field areas.
This is a problem that we need to become
familiar with to help reduce the yield reduction.
The problem first presented itself in the
fall of 1986 when several growers in the
Quincy area encountered plants in their fields
with unusual growth characteristics. Early
symptoms consisted of interveinal chlorosis in
the young leaves with veins remaining dark
green. Subsequently top growth became
severely distorted with leaflets along the midrib
failing to expand properly, resulting in a "little-
leaf" appearance. Additional symptoms
included cessation of terminal growth, leaflets
with twisted and brittle midribs and axillary
buds with distorted growth. The later
symptoms can be confused with cucumber
mosaic virus. Fruit that set when plants are
mildly affected are distorted with fruit being
flattened and at times having radial cracks
extending from the calyx to the blossom scar.
There is almost no seed set in affected fruit
and all fruit are unmarketable. In the more
severely affected plants, blooms are distorted
and fail to set fruit. Several growers
commented that the same set of symptoms
had been observed in the past, but only on a
very few plants. Following 1986, the set of
symptoms was referred to as "tomato little
leaf'.
Since 1986 the problem has been
observed sporadically in the fall crops in the
Quincy area. Occasionally the problem has
affected large areas and caused significant
yield reduction. It has only presented a
problem in one spring crop (1992) when "little
leaf was observed in the north Floridalsouth
Georgia production areas. I have received
reports of "little leaf" occurrence from Ohio,
Texas, Maryland, Poland and Italy.
To try and determine a cause,
numerous samples were sent to the Extension


Plant Diagnostic Clinic in Gainesville for virus
detection and all samples were negative.
Some growers believed the problem to be
nutritional, since from a distance some
symptoms emulated iron deficiency. Many
nutritional sprays including Fe, Ca, Zn and B
were made but to no avail. Extensive tissue
sampling and analysis were performed from
affected and non-affected plants. Nutrient
levels were determined for N, P, K, Ca, Mg, Fe,
Zn, Mn and B. The results failed to reveal an
abnormal nutritional situation. Extensive
testing of soil and plant tissue for herbicide
residues were also negative. One common
observation was that affected plants showed
up in the wetter areas of the fields. Finally,
cuttings made from distorted tops developed
normal growth habits after rooting.
In tobacco there exists a nonparasitic
disease called frenching. It is considered to be
a nonparasitic disease because the organism
or organisms that cause the disease do not live
within the tissues of the plant. Early symptoms
of frenching consist of chlorosis along the
margins of young leaves. The chlorosis
gradually spreads toward the midrib until all
interveinal regions are involved. The veins
remain dark green. As the leaf continues to
develop, only the midrib elongates producing a
long, ribbon-like leaf. Terminal growth is
greatly retarded and apical dominance is lost,
resulting in a stunted plant with an increased
number of small brittle leaves. The foliar
symptoms on tobacco are nearly identical to
the symptoms observed in tomato little leaf.
Tomatoes were mentioned to be sensitive to
the problem in the literature almost 60 years
ago but was never described. Similar
symptoms have also been reported on petunia,
eggplant, ragweed, sorrel (Oxalis stricta) and
squash. In chrysanthemums, the disorder is
referred to as yellow strapleaf and was a
problem of serious economic consequence to
chrysanthemum growers in Florida between
1956 and 1965.
The etiology of the conditions described
above is not completely understood. The
current hypothesis is that one or more amino
acid analogs are synthesized by certain soil
microorganisms and released into the


VEGETARIAN NEWSLETTER


November 1998








VEGETARJANNEWSLETTER November 1998


rhizosphere. These compounds, which are
structurally similar to the amino acid leucine,
are taken up by the plant causing
morphological changes and stunting in
susceptible plants at very low concentrations.
It is believed that these compounds act as an
antimetabolite of the amino acid leucine.
Currently, three soil microorganisms have been
implicated as the causal agent. The first
organism reported was the bacterium Bacillus
cereus. In controlled experiments, symptoms
of frenching were obtained from diffusion of a
compound produced by B. cereus into small
tobacco plants. B. cereus is a ubiquitous soil
inhabitant and has been observed in large
numbers in the root zone of tobacco plants with
frenching. Another organism that has been
implicated is the fungus Aspergillus wentii.
This organism has been shown to produce a
compound (ANCPA) which is a potent
antagonist of leucine. In the lab it has been
shown that ANCPA in minute quantities can
produce symptoms on tobacco similar to
frenching and can similarly affect the growth of
other crops such as bean, tomato, sunflower
and chrysanthemum. Inoculations of tobacco
plants with the soilborne fungus Macrophomina
phaseolina has also resulted in the appearance
of frenching symptoms. It should be noted
however, that often times symptoms fail to
develop after inoculation with these organisms.
The problem has been shown to be
more severe with warm soil temperatures. In
tobacco, symptoms can appear in 8 to 15 days
with soil temperatures of 950 F, but rarely
appear in soil temperatures of 700F or less.
Symptoms are more severe on neutral or
alkaline soils and are rarely observed with a
soil pH of 6.3 or less. Frenching of tobacco
and yellow strapleaf of chrysanthemum are
more prevalent on wet, poorly-aerated soils. It
is apparent that for the problem to occur
requires a fairly unique combination of
conditions with an appropriate soil
microorganism.
In tobacco, control measures can
include reduction of soil pH to about 6.3 or
less, or use of ammonium sulfate as the
nitrogen source to lower the pH around the root
system. In chrysanthemum production to
reduce the potential of the problem, it is
advised that soil moisture be maintained so as


tobacco and chrysanthemum, pulling the
affected plants up and replanting them, has
resulted in the plants growing out of the
disease. This remission of symptoms is
apparently the result of improved aeration and
perhaps by root pruning which resulted in
decreased uptake of toxins by the root system.
In recent years in north Florida we have seen
very little of the problem. Growers have
become aware of the need to monitor soil
moisture very carefully and make sure
waterlogged conditions do not occur. Lacking
definitive information, we cannot suggest any
radical changes in tomato culture at this time
for avoidance of the disorder other than
monitoring soil moisture levels to avoid
waterlogged conditions. Higher soil pH has
been implicated in tobacco but not
chrysanthemum. Changes in soil pH for
tomato should be approached carefully to
avoid problems that might accompany reduced
lime utilization. The problem does not seem to
carry over, since we have not seen the problem
in the next year after a field was affected. If it
caught early, drying a field out will usually
result in subsequent growth to be normal and
plants will set normal fruit.

(Steve Olson, Vegetarian 98-12)


Scheduling Irrigation Using
Tensiometers For Tomatoes On A
Calcareous Rocky Soil
Irrigation is essential for crops grown on
calcareous rocky soils. Due to the unique soil
characteristics and lack of crop specific
information, most growers are using the "kick
and feel" methods to determine the need for
irrigation, or they irrigate their crops at weekly
intervals regardless of the crops or rainfall.
These approaches lead to either over-or under-
irrigation. Under-irrigation may cause water
stress of crops and reduce yield and quality
while over-irrigation will leach nutrients out of
the root zone to cause groundwater pollution.
Therefore, it is necessary to develop more
accurate timing of irrigation to apply the
amount of water that the crop actually needs in
calcareous rocky soils in south Florida.
We (Yuncong Li, Renuka Rao, Herbert
Rrvan and Teresa Olczvk) initiated a trial to


VEG~ETARLR NE WSLETTER


November 1998








VE GE TA MAN NE WSLETTER November 1998


evaluate and demonstrate using tensiometers
to schedule irrigation for tomatoes in the spring
1998 at the Tropical Research and Education
Center, Homestead, FL. 'Sunbeam' tomatoes
were planted in Jan., 1998. The study included
four irrigation treatments (5,10, 15, and 20
cbar). Five tensiometers were installed at 6
inches depth for each irrigation treatment. All
of the tensiometers were calibrated with a
tensiometer vacuum calibration unit by Ms.
Teresa Olczyk, Miami-Dade County
Cooperative Extension Services. Tensiometers
were installed between tomato plants in the
center of beds and sealed with slurry from
screened soil (<2mm). A portable tensiometer
was used to read the tensiometers daily or
every other day and tensiometer readings were
used to schedule irrigation whenever soil
tension reached 5, 10, 15 or 20 cbar. A flow
meter was also installed in the line to measure
total irrigation amounts for each block.
Tomatoes were harvested three times. Total
number, total weight and color of fruit from
each plot were recorded. A field day was also
conducted on May 14, 1998. Principle,


purchasing, calibration, installation and
maintenance of tensiometers were discussed
in the field.
Results showed that tensiometers can
be successfully used as tools for scheduling
irrigation in rocky soils with proper calibration,
installation and maintenance of tensiometers.
Optimal irrigation at 10 cbar increased yield,
improved quality and reduced nutrient leaching
(Table 1). Based on results of this study, we
propose the following guidelines to interpret
tensiometer readings for vegetable irrigation in
calcareous rocky soils:
Reading 0-5: Soils are saturated or nearly
saturated with rain or irrigation. Discontinue
irrigation in this range to prevent waste of
water and leaching of nutrients.

Reading 10-15: Crops should be irrigated in
this range.

Reading 30 and higher: Plants probably show
symptoms of water stress. Tensiometers are
likely to lose vacuums.


Table 1. Effects of irrigation treatments on fruit yield and quality of tomatoes in 1998.
Total Total
Irrigation TMatale Red Green Large tal Red Green Large
Marketable Marketable

cbar -...... Fruit yield (Cartons/Ac) ---------Fruit numbers per ac
5 1319b 1154ab 109b 930b 103556a 84434a 14845b 58317b
10 1578a 1330a 171ab 10997a 122056a 95108a 21058a 67095a
15 1377b 1143ab 162ab 1014ab 106460a 79916a 20977a 64287ab
20 1396b 1126b 201a 960b 117263a 86443a 26060a 66151a
Each mean represents the average of six observations. Values followed by different letters are
significantly different from each other at p<0.05 according to duncan's multiple range test.
(Yuncong Li, Vegetarian 98-12)


Vegetable Gardening


Disease Resistant Tomato Varieties
for the Home Gardener

The following varieties were listed in
1997-1998 seed company catalogs as being
resistant or tolerant to one or more of the
Fi~llhf.riftf! ^ hmn^ n +^ r linhn*C aterf rr lrvi 4 tr"il


verticilluim wilt, grey leaf spot, leaf mold, root
knot nematode, tomato mosaic virus, or some
other disease common to Florida.
Those with an (F) designates that variety
as recommended for Florida gardens.
The list was made by Jenny knight,
Georgina Sydenham, and Gary Simone of
the Plant Pathology department, from a
representative sample of the major seed
company catalogs available to Florida
home gardeners.(See PP/PPP43(Rev 3) 6-98)


VIEGETARUNNNEWSLETTER


November 1998







VEGEARIA NEWLETTR Noembe 199


Disease Resistant Tomato Varieties for the Home Grower


Abraham
Lincoln
Improved
Acclaim
Ace 55
Ace High
Imperial
AIIStar
Aztec
Beefmaster
Beefsteak
Beef King
Better Boy (F)
Better Bush(F)
Big Beef
Big Girl
Big Pick
Big Red
Champion
Bingo
Boa
Bonita (F)
Buffalo
Burpee's Early
Pick
Burpee's VF
Hybrid
Bush Goliath
Cabernet
Cal-Ace
Campbell's 1327
Carmello
Carnival
Caruso Hyb (F)
Casa del Sol
Cavalier
Celebrity (F)
Champion
Cherry Grande(F)
Classica
Cobra (F)
Colonial (F)


Container
Choice
Creole
Crimson Fancy
Daybreak
Delicious (F)
Del Oro
Dona
Duke (F)
Early Cascade
Early Girl (F)
Empire
Enchantment
Enterprise
First Prize Hybrid
First Lady
Flavor-More 180
Floradade (F)
Floradel (F)
Floramerica (F)
Florida Basket (F)
Florida Petite (F)
GS 12
Gold Dust
Good 'n Early
Greenhouse
109VT
Greenhouse 656
Greenhouse 761
Halley
Hawaiian
Hayslip (F)
Heartland
Heatwave (F)
Heavy-weight
Heinz 1350
Heinz 1439
Homestead 24 (F)
Husky Cherry
Gold (F)
Husky Cherry
Red


Husky Pink
Husky Red
Hybrid Gurney's
Burgemaster
Hybrid Miracle
Sweet
Hybrid Pink Girl
Italian Gold
Jackpot
Jet Star
Johnny's 361
Joker
Jubilee (F)
Jumbo
Keepsake Hybrid
Kyndia
Lady Luck
La Roma (F)
La Rossa
Lemon Boy (F)
Liberty
Manalucie (F)
Marglobe (F)
Marglobe
Improved (F)
Marion (F)
Marmande
Milano
Miracle Sweet
Monroe
Monte Carlo
Mortgage Lifter
Mountain Belle
Mountain Delight
Mountain Fresh
Mountain Gold
Mountain Pride
Mountain Spring
Mountain Supreme
Napoli
New Yorker
Odoriko


Ole
Olympic (F)
Orange Pixie
Oregon Spring
Paragon
Park's Early
Challenge
Hybrid
Park's Whopper
Improved (F)
Patio (F)
Pearson's A-1
Improved
Perfect Peel
Pik Red
Pilgrim
Pink Girl
Pink Odoriko
Pole King
Pueblo
Quick Pick
Red Rose
Red Sun
Rio Grande
Rodade
Roma VF (F)
Rose Quartz
Cherry
Rutgers (F)
Salsa
San Remo
Sausalito (F)
September Dawn
Sierra
Small Fry (F)
Solar Set (F)
Spectrum 385
Spitfire
Spring Giant
Spring Set
Sprinter
Stakeless (F)


Subarctic Plenty
Sugar Snack
Hybrid
Summer Flavor
Sunbeam (F)
Sun Cherry (F)
Sun Coast (F)
Sun Gold (F)
Sungold Red
Sunmaster
Sunny (F)
Sunray (F)
Super Beefsteak
Super Bush
Super Chief
SuperFantastic(F)
Super Marzano
Super Roma VF
(F)
Supersonic
Supersteak
Supersweet 100
(F)
Sweet 100 (F)
Sweet Chelsea (F)
Sweet Gold
Sweet Million (F)
Sweet Quartz
Terrific (F)
Toy Boy
Tropic (F)
Tuscany
Ultra Boy
Valley Girl
Veronica
Viva Italia(F)
Voyager
Walter (F)
Wonder Boy


(Jim Stephens, Vegetarian 98-12)


VEG~ETARIANNEWSLETTER


November 1998







VEGETARIAN NEWSLETTER November 1998


Prepared by Extension Vegetable Crops Specialists


Dr. D. J. Cantliffe
Chairman


Dr. D. N. Maynard
Professor


Dr. W. M. Stall
Professor


Dr. J. M. White
Assoc. Professor


Dr. T. E. Crocker
Professor


Dr. S. M. Olson
Professor


Mr. J. M. Stephens


Dr. G. J. Hochmuth
Professor


Dr. S. A. Sargent
Professor


Dr. C. S. Vavrina
Assoc. Professor


VEGETARL4NNEWSLETTERR


November 1998




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