INSTITUTE OF FOOD AND
UNIVERSITY OF FLORIDA
A Vegetable Crops Extension Publication
Vegetable Crops Department* 1255 IlSPP Gainesville. FL 32611 Telephone 392-2134
I. NOTES OF INTEREST
A. Vegetable Crops Calendar.
II. COMMERCIAL VEGETABLES
A. Florida Tomato Institute.
B. Why Are We Concerned About
August 15, 1989
C. Virus in the Plant House and the Field.
D. Estimating Mechanical Injury During Tomato Handling
Using the Instrumented Sphere.
III. PESTICIDE UPDATE
A. Pesticide Reregistrations.
IV. HOME GARDENING
A. 1989 4-H Horticulture State Events Winners.
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 Institute of Food and Agricultural Sciences is an Equal Employment Opportunity Affirmative Action Employer authorized to provide research.
al.t-irtinnot infnrmrtinn andr nthar caruira nnlu tn indiulerlalt andr inctitltitnns that fuInction without reaard to race color, sex. or national origin.
L NOTES OF INTEREST
August 23-25, 1989. Florida
Master Gardener Continued Training
Conference. Reitz Union, University of
Florida, Gainesville. (Contact Kathleen
Ruppert, Ornamental Horticulture).
6, 1989. Florida
September 7-8, 1989. Florida
Tomato Committee/Exchange Meeting.
Ritz-Carlton Hotel, Naples, Florida.
October 31-November 2, 1989.
Florida State Horticulture Society. Hyatt
II. COMMERCIAL VEGETABLES
A. Florida Tomato Institute.
1989 Florida Tomato Institute
Wednesday, September 6, 1989
9:00 Registration and Coffee
9:20 Welcome and Announcements
9:30 Irregular Ripening
Report of the Task
Force. D. J.
10:20 Management of Weeds and Crop
Residues. J. P. Gilreath, Gulf
Coast REC, Bradenton.
10:40 Biology and Management of Thrips
and Tomato Spotted Wilt Virus. J.
E. Funderburk, No. Fla. REC
11:10 Target Spot, Early Blight, Bacterial
Spot and Bacterial Speck:
Identification and Control. J. P.
Jones, Gulf Coast REC, Bradenton.
11:30 Questions and Discussion
Lunch on your own.
Food Safety: The Media Crises for
the 80's. Martha Rhodes, Assistant
Commissioner, Florida Dept. of
Agriculture and Consumer Services,
2:00 Reregistration Process and its
Potential Impact on Florida
Production. D. A. Botts, Florida
Fruit and Vegetable Association,
2:20 Tomato Breeding Projections for
the 90's. J. W. Scott, Gulf Coast
2:40 Nitrogen and Potassium
Fertilization in Seep Irrigated
Tomatoes. P. R. Gilreath, Manatee
County Cooperative Extension
3:00 Effect of Pruning on Yields, Fruit
Weight and Percent Marketable
Fruit of 'Sunny' and 'Solar Set'. S.
M. Olson, North Florida REC,
3:20 Methane Production from Culled
Tomatoes. D. W. Williams,
Agricultural Engineering Dept.,
California Polytechnic State
University, San Luis Obispo, CA.
3:40 Estimating Mechanical Injury
During Tomato Handling using the
Instrumented Sphere. S. A.
Sargent, Vegetable Crops Dept.,
4:00 Questions and Discussion
(Stall, Vegetarian 89-08)
B. Why are we concerned about
fertilizer nutrient ratios?
I am going to use this article to
stir some thought by asking the above
question specifically about nitrogen and
potassium ratios for tomatoes. I'll go a
step further and state that I do not
believe ratios mean anything and have no
place in our fertilizer programs. There
are several reasons for my skepticism on
First of all, there is a serious
problem in the ratio concept since one
can not separate the nutrient rate effects
from the ratio effects in a "ratio"
experiment. Therefore, any treatment
effects could as easily be explained by
rate effects as by a ratio effect.
My major skepticism arises from a
soil-testing point of view. I have seen too
many soils (tomato farms) where the soil
could supply a major portion of the
potassium crop nutrient requirement for
high quality and high yielding tomato
crops. This means that there is lots of
potassium in the soil of these fields.
Therefore, how can it matter when
someone applies a 2K20 to 1 N fertilizer
material? The ratio is no longer what we
thought we were providing the crop.
Furthermore, our Florida soils are not
hydroponic in nature. There is a lot of
soil chemical reactions going on that
affect nutrient availability and, as a result,
I can not believe that our special-ratio
fertilizer is still our special-ratio fertilizer
after we apply it to the soil whether by
broadcasting or by banding.
A third factor is that any research
that I know of on the relation of nutrition
to tomato yield and fruit quality ascribes
much of the effects to factors other than
nutrition. There might be a potassium
rate effect but not ratio. In fact, some of
the early work in Florida (on which I
assume current fertilizer ratio theory is
based) points out the importance of the
environment in the disorder of study
(gray wall). During the last few seasons
several of us from Gainesville, along with
several county agents have been studying
N and K for several vegetable crops,
including tomato. We have had a difficult
time coming up with simple K rate effects
much less anything that has to do with
I believe we need to re-examine
this ratio philosophy in light of real, hard
research data. In this respect, I do not
think the ratio idea can stand up. The
philosophy flies in the face of soil testing
because it disregards the K that we know
exists in Florida soils. The theory also
forces growers to purchase more K than
they need. For a reasonable N rate of
200 pounds per acre (tomatoes), the
grower must use in the area of 400
pounds of K20. We know of situations
where 400 pounds of N are used commer-
cially. This means that 800 pounds of
KIO are required by the ratio concept.
This could be the source of some of our
soluble salt troubles!
Yes, I am skeptical but not totally
close-minded. If anyone has data that can
irrefutably support this ratio concept, I'd
like to see it. Otherwise, let's start
teaching growers the soil-testing way and
get away from the ratios.
(Hochmuth, Vegetarian 89-08)
C. Virus in the plant house and
Virus in the plant house can be
devastating for the grower. Viruses can
be transmitted mechanically, via insect
vectors, or come in on the vegetable seeds
themselves. Mechanical transmission is
not a major route of transmission, how-
ever tobacco mosaic virus (TMV), potato
virus X & Y, and tobacco etch virus can
be spread mechanically. TMV has been
reported to retain its virulence for up to
50 years in dried leaf samples! TVM can
be neutralized by dipping hands in milk
or hydrated phosphate detergent before
Virus contaminated seed is a consi-
deration notably for bean mosaic, blackeye
cowpea mosaic, cucumber mosaic (CMV),
and lettuce mosaic. Many vegetable crops
can become infected with CMV (including
Solonaceous fall transplant crops) but
transmission is generally by aphids in the
field. CMV has not been a major problem
in Florida crops since the early 1970's.
By and large, insects are the most
important agents of viral transmission.
Insect vector plant house virus is less of
a problem than a field occurrence because
roqing and a good scouting program in
the house can keep virus in check.
Drs. Kucharek and Purcifull have
recently cataloged the viruses that have
occurred in Florida vegetable crops (ppp
7), and DPI, 1984 edition of the Index of
Plant Diseases in Florida lists many
possible additional alternate hosts.
A weed control program is impor-
tant in reducing the possibility of insect
transmitted virus in the plant house. A
partial cataloging of virus-harboring
Florida weed host plants indicates some
interesting relationships. Insect
transmitted vegetable crop viruses are
more likely to be transmitted from a weed
within the same botanical family. How-
ever, while this is certainly not a rule,
cross transmission of grass and broadleaf
viruses is rate.
Some species of weeds are capable
of propagating several species of virus.
Black nightshade, (Solanum americanum
L.) and ground-cherry (Physalis spp.), are
particularly troublesome weeds in Florida
tomato and pepper fields, and may harbor
up to four separate viruses concurrently:
Tomato Yellows Virus, Tobacco Etch Vi-
rus, Potato Virus Y, Tobacco Mosaic Virus.
Other weeds of concern include:
cressleaf groundsel (Senecio glabellus),
hairy beggarticks (Bidens Dilosa) and
Virginia pepperweed (Lepidium virgini-
cum) for Bidens Mottle Virus (lettuce,
endive, escarole), wandering jew (Comme-
lina spp.) for Cucumber Mosaic Virus (25
vegetables), jimsonweed (Datura stra-
monium) in Solanaceous crops for Tobacco
Etch, Tomato Yellows Virus, and Potato Y
Virus, lambsquarters (Chenopodium
album) for Lettuce Mosiac Virus (lettuce,
endive, escarole), and creeping cucumber
(Melothria pendula L.) and balsam apple
(Clusia rose) for Watermelon Mosaic
Virus 1 (Cucurbit crops).
(Vavrina, Vegetarian 89-08)
D. Estimating mechanical injury
during tomato handling using the
Minimizing mechanical injury
during handling is one of the primary
goals of Florida tomato packer/shippers.
Tomatoes experience a number of
transfers during typical harvest, handling
and packing operations, and each of these
transfer points has potential to reduce
quality by inflicting bruises, cuts,
punctures and abrasions. Recently, a
prototype instrument became available
which is capable of measuring impact
accelerations experienced during handling
operations. This Instrumented Sphere
(IS) is a battery operated data logger
which is 3.5 inches in diameter and has a
density similar to that of a tomato. It
can be placed on a packing line in order
to record impact times and intensities at
transfer points in the line. The IS was
originally developed at the USDA/ARS
laboratory at Michigan State University in
East Lansing, Michigan, for analyzing
apple handling systems. We purchased an
IS to develop a database for vegetable
handling systems as part of a cooperative
research project involving several research
institutions and a variety of horticultural
This past spring season we began
a program, 1) to develop a database of
impacts at transfer points during tomato
handling using the IS; 2) to document
actual mechanical injury for a range of
tomato handling and packing situations in
Florida; and 3) to correlate IS data with
actual injury data in order to allow
prediction of potential injury sites for
packing line using impact values
measured by the IS. The extent of
mechanical injury was previously
described in The Vegetarian (89-07). In
this issue we will briefly discuss results of
the IS tests.
The IS was run over three tomato
packing lines during the spring of 1989.
The following procedure was employed
during the tests. While the line was
running at typical capacity, the IS was
activated and placed in the line, beginning
in the bulk bin. It was allowed to flow
over several transfer points while the
elapsed time was recorded at each point.
The IS was then removed and the data
was transferred to a portable computer.
This procedure was repeated ten times for
each segment of the packing line until
the entire line was documented. Averages
were later taken for the ten runs at each
The impact averages as measured
by the IS showed that the highest
impacts generally occurred where there
was a roll or drop onto a metal plate
followed by rebound to a roller conveyor;
another point was where there was a roll
down a steep incline onto a roller. These
points included drops to wash brushes,
sorting rolls, accumulator belts and cross
conveyors. Transfer points which were
not as severe were the drops to float
tanks and eliminator belts.
The average impact per transfer
point measured on the Green Lines for
the three packing lines was about 20%
lower than the average impact measured
on the Pink Lines. This could cause
injury since tomatoes showing color are
less firm than those which are at the
mature green stage and therefore are
more sensitive to impacts.
Every point in which a fruit or
vegetable is transferred from one type of
equipment to another is a potential site
for increased mechanical injury.
Therefore, the packing lines which cause
the least injury are straight, with no
major turns during handling, and level,
with minimal drops at transfer points.
Packing lines should be designed and
managed to handle the most injury
sensitive crop, in this case, tomatoes
which are showing color. For existing
lines, transfer points should also be kept
clean, smooth and padded over surface
protrusions. Brush rolls should be set at
sufficient speed so as to provide adequate
washing without causing excessive fruit
movement and increased fruit to fruit
contact. Drop heights and transfer plate
angles at transfer points can be lowered.
Installation of curtains or power brushes
at these sites can also facilitate transfer
while reducing mechanical injury.
In further tests in the laboratory
and in packinghouses this next season we
will attempt to establish IS impact
thresholds with actual damage incurred
during tomato handling.
(Sargent, Vegetarian 89-08)
III. PESTICIDE UPDATE
A. Pesticide Reregistrations.
According to the provisions of the
1988 amendments to FIFRA, the EPA is
mandated to accelerate the reregistration
process for previously registered pesti-
cides. Registered uses of pesticides will
be lost because of this accelerated reregis-
In general, the reregistration pro-
cess has been divided into 5 phases: (1)
Identification, categorization, and regis-
trant notification of active ingredients
subject to reregistration; (2) Response
from the registrant as to whether or not
they intend to reregister the product,
identification of data requirements; (3)
Submission by registrants of summaries of
previously submitted studies with subse-
quent commitment from registrant; (4)
Agency review of phases 2 & 3 and the
identification of outstanding data require-
ments with the corresponding notification
and commitment by registrants to fulfill
those requirements, and; (5) Agency
review of all data and determination of
appropriate regulatory action.
IR-4 has mailed a IR-4 Red Alert
(Number 5, June, 1989) that contain a
listing of all food crop uses which are
subject to reregistration.
The Florida Fruit and Vegetable
Association has mailed to many of their
members an edited list of chemicals and
asked for their input and letters of
concern to affected chemical companies.
It is believed that many of the food
crop uses will be defended by the
manufacturers. However, their resources
are limited and it is unlikely they will
defend all uses for minor use crops such
as vegetables or defend older compounds
which are not patent protected or have
lost a major share of the agronomic
Rhone-Poulenc, in a letter to me,
has already stated that they will not
I have sent a list of compounds up
for reregistration that have vegetable
labels to agents and specialists in major
vegetable producing counties in Florida.
IR-4 has stated that they will
assist, where applicable in the reregis-
tration of compounds having the highest
priority and greatest need in vegetable
Several meetings will be held this
fall both for the southern region and for
National priority setting phase 2 of the
reregistration process is completed.
I plan to attend both meetings for
vegetable herbicides. I have and will seek
more help in the prioritizing process for
Any time between now and the
meetings I will be appreciative of any
thoughts that anyone may have.
(Stall, Vegetarian 89-08)
IV. HOME GARDENING
A. 1989 4-H Horticulture State
Tuesday, July 25, 1989 was the big
day many young 4-H horticulturists had
been preparing for and looking forward to
for a long time. It was State Events day,
held during the week of 4-H Congress,
and a chance to visit the University of
Florida campus at Gainesville. Everyone
knew competition would be tough much
tougher than at earlier training events
conducted at State Fair and Hort
Institute. Those were mere warm-ups -
this was it!
First on Tuesday morning came
the Plant Science Demonstrations. Thir-
teen of the district finalists met heads-on
in Fifield Hall, our state's headquarters
for horticulture. Subjects for the illu-
strated talks and demonstrations were as
wide and varied as the speaking styles of
the youthful participants, ages 14 to 17.
Titles were lively and innovative, but the
meat of the subjects were as follows:
Soils, Grafting, Transplants, Bonsai, Tree
Planting, Fertilizing, Citrus, Herbs, Roses,
Christmas Trees, and Tissue Culture.
From the first, "Hello, my name is
Susannah Evans, and I'm from Walton
County," to the last "This concludes my
demonstration, are there any questions?",
it was obvious the three graduate stu-
dents judging the event were really going
to be challenged deciding who was the
best. But meeting challenges was nothing
new to Leah Willis (Fruit Crops), Barbara
Poole (Ornamentals), and Tom Wall
(Vegetable Crops), so decide they did, and
here are the results:
1st Place Susannah Evans,
Walton County, "How to Evaluate Soils for
Land Use and Development".
2nd Place Amy and Leslie Theus,
Marion County, "Thoroughbred Trees."
3rd Place Janet Jones, Gilchrist
Blue Ribbon Awards went to: Eric
Kinslow (Manatee), Heather Anderson
(Pinellas), Kevin Crowell (Polk), Nicole
White (Okeechobee), and Dawn March
(Broward). Red Ribbons were awarded to:
Steve Forehand (Gulf), Amy Thompson
(Jackson), Mark Lares (Brevard), Jenni
Meriwether (Seminole), and Jimmy
We congratulate all these demon-
strators on a fine job well done!
Now, for Susannah it will be "on to
Baltimore" for the national competition
during the National Junior Horticultural
Association Convention, Oct. 27-30, 1989.
We wish her well.
O.K., the demonstrations were
awesome, but check out the identifiers
and judgers. In the afternoon of that
same day, Tuesday, they went toe to toe
and green thumb to green thumb in the
State Horticulture Identification and
Judging event. For the eight official
county teams and 27 participants, team
coaches had done all they could, and now
it was up to each individual to help their
Fruits, vegetables, flowers, and
shrubs were laid out in every direction.
Muffled wails and murmurs filled the air:
"What could this possibly be? Looks like
anthers to me, but from what? Come on,
deductive reasoning, where are you when
I need you?"
And when the dust finally settled
in the new OH greenhouse classrooms be-
hind Fifield Hall, the cream had risen to
the top, and Florida had a new State 4-H
Horticultural ID and Judging team.
Where from? You may have guessed it -
The top team was led by the con-
test's high individual, Ann Yawn, with 825
points; teammates were Leslie Theus
(811), Jeanne Fugate (801), and Tobitha
Bryant (771). Proud coach Bob Renner,
Marion 4-H Agent, will accompany his
team to Baltimore and the NJHA
convention in October for the National
finals. Good luck!
Here are the team placings: (1)
Marion; (2) Duval, (3) Sarasota; (4) St.
Johns; (5) Leon; (6) Martin; and (7)
Sponsors are Florida Fruit and
Vegetable Association, Florida Department
of Agriculture and Consumer Services,
and Florida 4-H Foundation. Zellwin
Farms also contributes to the training of
(Stephens, Vegetarian 89-08)
Prepared by Extension Vegetable Crops Specialists
Dr. D. J. Cantliffe
Dr. G. J. Hochmuth
Dr. S. M. Olson
Mr. J. M. Stephens
Dr. C. S. Vavrina
Dr. D. D. Gull
Dr. D. N. Maynard
Dr. W. M. Stall
Dr. S. A. Sargent