INSTITUTE OF FOOD AND
UNIVERSITY OF FLORIDA
A Vegetable Crops Extension Publication
vegetable Crops Department 1255 I SPP* Cainesilic, FL 32611 Tleplhoii 392-2134
July 15, 1989
I. NOTES OF INTEREST
A. Vegetable Crops Calendar.
B. New Publications.
II. COMMERCIAL VEGETABLES
A. Transplant Production Fall '89.
B. Ethylene Culprit or Cure?
C. Fall Cucumber Production.
D. Assessment of Mechanical Damage in Tomato
III. VEGETABLE GARDENING
A. 1989 Horticulture Institute a Success.
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,
educational information and other services only to individuals and institutions that function without regard to race, color, sex, or national origin.
COOPERATIVE EXTENSION WORK IN AGRICUL TURF AND HOME ECONOMICS. STATE OF FLORIDA. IFAS. UNIVERSITY OF
I. NOTES OF INTEREST
July 24-28, 1989. State 4-H
Horticulture Events 4-H Congress.
Gainesville. (Contact Jim Stephens).
July 30 Aug. 4, 1989. ASHS
Convention, Tulsa, OK.
August 23-25, 1989. Florida
Master Gardener Continued Training
Conference. Reitz Union, University of
Florida, Gainesville. (Contact Kathleen
Ruppert, Ornamental Horticulture).
September 6, 1989. Florida
Tomato Institute. Ritz-Carlton Hotel,
September 7-8, 1989. Florida
Tomato Committee/Exchange Meeting.
Ritz-Carlton Hotel, Naples, Florida.
October 31-November 2, 1989.
Florida State Horticulture Society. Hyatt
B. New Publications.
"Super Sweet" Sweet Corn Variety
Demonstration Delray Beach, Florida,
Winter 1988-89, K D. Shuler, Palm Beach
County Extension Report 1989-1.
38th Vegetable Field Day, May 18,
1989, J. P. Jones, D. N. Maynard, W. E.
Waters, Bradenton GCREC Research
Report BRA 1989-7.
Tomato Variety Trial Results for
Fall 1988, T. K. Howe, J. W. Scott and W.
E. Waters, Bradenton GCREC Research
Evaluation of Strawberry Cultivars
and Advanced Selections at Dover, Florida
1986-1988, C. K. Chandler, E. E. Albregts,
and C. M. Howard. Dover AREC
Research Report DOV-1988-1, June, 1988.
Strawberry Variety Trials 1988, E.
E. Albregts, C. K Chandler, and C. M.
Howard. Dover AREC Research Report
The History, Development,
Accomplishments and Programs of the
Agricultural Research and Education
Center Dover, Florida 1925-1989.
E. E. Albregts, C. M. Howard, C. K.
Chandler, and W. E. Waters. Dover
AREC Research Report DOV 1989-1.
Cucumber Variety Trial, Fall 1988,
T. K Howe and W. E. Waters, Bradenton
GCREC Research Report BRA1989-5.
Chinese Cabbage Cultivar
Evaluation on Sandy Soil During the
1987-88 Season, T. K. Howe and W. E.
Waters. Bradenton GCREC Research
Evaluation of Cauliflower in West-
Central Florida During the 1987-88
Season. T. K. Howe and W. E. Waters.
Bradenton GCREC Research Report
Sweet Corn Variety Trial -
Supersweets Spring 1988, T. K. Howe and
W. E. Waters. Bradenton GCREC
Research Report BRA1989-3.
1988 Publication List GCREC-
Bradenton and AREC-Dover, GCREC
Research Report BRA1989-1, W. E.
H. COMMERCIAL VEGETABLES
A. Transplant Production
Producers of fall vegetable
transplants should be highly concerned
with sanitation. Not just within the plant
house, but around the plant house and in
fields adjacent to the plant house.
It isn't practical to expect
production fields in the vicinity to remain
vacant until transplant production is
complete. Neither is it possible to keep
those fields and ditch rows clean while
large scale field planting is going on.
Consider this: when is a weed not
just a weed? When that weed is also a
host for disease and insects. It's no
secret that tomato, bell pepper and
tabasco pepper can readily exchange
bacterial leaf spot (Xanthomonas
campestris (Pamm.) Dows. pv. vesicatoria
(Doidge) Dye) organisms in the plant
house, especially when overhead irrigation
is used. But when black nightshade
(Solanum nigrum L.) and ground-cherry
(Physalis spp.) are also hosts for bacterial
leaf spot you may be harboring a ready
source of inoculum close by. Dr. Schuster
at the Gulf Coast Research and Education
Center, indicates these weed species are
also excellent hosts for the sweetpotato
One might expect an interchange
of disease and insect pests among plant
species within the same family. Other
members of the family Solanaceae which
may contribute to plant house disease
problems include tobacco (tobacco users
can readily spread TMV), petunia, jasmine
(Cestrum), and Jimsonweed (Datura
Fall eggplant, already in the field,
can contribute late blight (Phytophthora
infestans (Mont.) d By.) and any spring
crop tomato residue can provide the aerial
spores of crown rot (Fusarium oxysporum
Schlect. f. sp. radicis-lycopersici Jarvis
and Shoemaker) to add to the problems.
In the spring, while fruit production is
slowing, but transplant production for
northern markets is increasing, old fruit
and vines from the crops themselves can
present a formidable source of infection.
Unrelated plant species may also
contribute to plant house disease
problems. For example showy crotalaria
(Crotalaria spectabilis) is a host for gray
mold (Botrvtis cinerea Pers. ex Fr.);
cowpea (Vign unguiculata (L.) Walp.) is
a host for another bacterial leaf spot in
pepper and bacterial canker in tomato
(Pseudomonas syringae van Hall pv.
syringae van Hall) as are peach, nectarine,
and most citrus species. Unfortunately
the study of most plant disease and insect
pests centers around economically
important plants. This means more
unknowns are involved in identifying
weed species as pest hosts. Therefore
good weed control is a necessity in and
around the plant house.
(Vavrina, Vegetarian 89-07)
B. Ethylene culprit or cure?
Ethylene is used routinely to
initiate ripening of such products as
mature green tomatoes, honeydew melons,
and bananas. However, with greater
frequency we recognize deleterious effects
upon products such as lettuce, carrots,
sweet corn, and watermelons when they
have been exposed to even small amounts
of ethylene. Generally speaking, exposure
of fresh vegetables to ethylene at the
packinghouse or in storage is not
intentional and thus conclude that
exposure has not occurred. Furthermore,
deleterious effects of exposure to ethylene
are not apparent initially, but show up
later at terminal market or during
Ethylene concentrations of 150
ppm or more, are used for ripening
initiation even though biological systems
may be activated at concentrations as low
as 0.1 ppm. Fresh products in the
vicinity of these ripening facilities where
ethylene is used may be a high risk for
exposure, but what about products where
ethylene is not intentionally used?
Ethylene is contained in the
exhaust emissions from diesel trucks and
gasoline powered fork lifts produce very
high levels of ethylene. There is
increased ethylene in metropolitan areas
but fortunately for Florida this increase is
minimal as compared to a particularly
smoggy day in the Los Angeles area
where ethylene levels can rise to over
0.15 ppm between 8 a.m. and noon.
At the packinghouse level or in
storage, if fork lift emissions are the main
source of ethylene, catalytic converters
installed on the lift trucks will reduce
ethylene levels; converters can reduce
ethylene emissions by about 90%.
However, ventilation with outside air
seems to be the best method of ethylene
control in air refrigerated storage
operations. Ventilation is the least
expensive ethylene control method and
particularly if major ventilation occurred
at night when outside concentrations of
ethylene would be at the lowest level.
The major expense would be cost of fan
operation and the extra refrigeration
required. Alternative methods would be
ethylene scrubbers or UV radiation; both
appear to be very energy inefficient and
therefore more costly.
Following are some fresh
vegetables with their relative sensitivity
to ethylene exposure:
Celery Sweet corn
(Gull, Vegetarian 89-07)
C. Fall cucumber production.
Slicing cucumbers are a
popular vegetable for fall production in
Florida, often selected as the second crop
in a double-crop system. Don Maynard
always correctly says that cultivar
selection is an important first step in a
vegetable planting program. Fall
cucumber production presents extra
problems because of the heat, rainfall, and
diseases. To gather information on the
performance of fall cucumbers, we
conducted a fall slicing cucumber variety
trial on plastic mulch at the Live Oak,
AREC. We have included a summary of
that trial for your use. If you need a
complete copy of the report contact us.
Overall, it appears that 'Dasher IT'
and 'Superset' were the best performing
cultivars in this trial. Both were in the
highest yielding class for early and total
marketable yields. In addition, both
cultivars produced high yields of fancy
and U.S. No. 1 grade fruit. 'Comet A2'
performed in the intermediate class for
earliness but ranked low for total yields.
This cultivar is evidently early, but does
not produce high yields over an extended
harvesting season. 'Monarch' and
'Revenue' were intermediate in their
performance in both early and total yield
when evaluations are made based on
quality and yield. 'Centurian' performed
well for total seasonal yield, but it appears
to be a late cultivar since its early yield
from the first two harvests was low. The
poorest performing cultivars in this test
were 'Striker' and 'General Lee'. Both
had low early yields and low total seasonal
yields when both quality (fancy and U.S.
No. 1 fruits) and yield were considered.
Total yield (7 harvests) of eight slicing cucumber cultivars grown
on plastic mulch in fall, 1988 at Live Oak, FL.
Yield by grade category (bushels per acre basis)
Cultivar Seed Source
No. 1 No. 1
Small No. 2 Cull Tbtal
Centurian Northrup King 261 164 47 78 137 50 687
Comet A2 Asgrow 184 154 73 120 120 58 651
Dasher II Peto 285 179 35 126 120 57 745
General Lee Ferry Morse 197 151 44 138 110 36 641
Monarch Asgrow 176 152 151 87 132 60 699
Revenue Ferry Morse 252 129 80 108 109 48 678
Striker Asgrow 252 156 39 106 92 47 610
Superset Peto 239 153 50 116 126 56 684
(B. Hochmuth, G. Hochmuth, Vegetarian 89-07)
D. Assessment of mechanical damage
in tomato packinglines.
A study was begun this past spring
to determine the extent of damage
occurring to tomatoes during typical
handling operations. During May and
June three tomato cultivars ('Solar Set',
'NK-4459', 'Sunny') were sampled at two
ripeness stages (mature green (MG) and
breaker (BR)) and at three points during
packing. The sample locations were in
the float tank, after final grading (prior to
sizing), and after stacking the carton on
the pallet. The samples were held at
22C until all fruits reached the firm, red
ripe stage and then were evaluated for
external mechanical injury and internal
External injuries scored were:
bruises, cuts/punctures and abrasions.
Internal bruising is apparent after slicing
the ripe tomato through the equator; the
locular gel appears shrunken and yellow-
green in color, and the seeds are often
disorganized. IB occurs when mature
green or breaker tomatoes receive an
impact of sufficient force to disrupt
normal ripening. In many instances of IB
there is no externally visible bruise on
the tomato surface.
The results showed that tomatoes
handled MG were generally more
sensitive to abrasions, while those handled
at BR were more sensitive to external
bruises. After sorting and grading
operations the number of externally
damage-free tomatoes increased an
average of 20% over the samples taken
from the float tank, indicating the
importance of the grading operation.
Incidence of internal bruising in BR
tomatoes was double that of MG
tomatoes. Samples of BR for 'Solar Set',
'NK-4459'and 'Sunny' had 57.1%, 68.2%
and 40.0% of the locules with IB,
respectively. IB also increased
proportionally with handling; handling
after grading caused the incidence of IB
to increase 5.2% to 23.8% for these
cultivars. MG tomatoes had significantly
more locules with seeds than BR
(averages of 6.0 and 5.0, respectively)
which might provide MG more rigidity,
and, therefore, more resistance to IB
Studies are being undertaken to
identify transfer points during handling
which are likely to cause mechanical
injuries and to determine the maximum
threshold levels for tomato impacts to
(Sargent, Vegetarian 89-07)
III. HOME GARDENING
1989 Horticulture Institute a
Sixty-six 4-H'ers and about 15 adult
leaders attended the week-long 4-H
Horticulture Institute, June 19-23, 1989,
at Camp Ocala (Lake County) Florida.
Campers came from all over Florida, from
Broward County to Wakulla County.
We call it an Institute rather than a
camp, due to the educational focus on
horticulture. There were 20 classes as
1. Cacti and Succulents (Virgle
Schwable, Marion Master Gardener).
2. Shiitake Mushrooms (Clay Olson,
Taylor Co. Ext. Director)
3. Forest Ecology (Nancy Powell -
4. Horticulture Photography (Ray Zerba
Clay Co. Ext. Hort)
5. Television Videotaping (Andrea Smith
6. Butterfly Gardening (Joe Schaeffer -
7. Gardening with Leftovers (Betsy
Davis Highlands Co. Ext. Hort)
8. Vegetable Print Presses (David Hall,
9. Photosynthesis (Jou Sutphin-Sarasota
Co. Ext. Hort)
10. Plant Growth Regulators
Williamson, Fruit Specialist)
11. Interiorscaping (Richard Henley, Hort.
12. Soils (David Griffis, Volusia County)
13. Lake Water Quality (Sandy Fisher,
IFAS Water Specialist)
14. Composting (Shirley
Alachua Co. Ext. Hort)
15. Chilled Fruits (Jeff Williamson,
16. Vegetables in Containers
Brown, Duval Ext. Hort)
17. Landscaping to Conserve Energy
(Bob Black, Urban Hort.)
18. Snacks from Fruits (Alice Ayers,
Lake Co. Ext.)
19. NJHA (Bob Renner, Marion Co.
20. Horticulture Posters (Keith Fuller,
St. Johns Co. Ext. Hort.)
In addition to attending these classes,
the 4 H'ers, who ranged from 10 to 17
years of age, learned how to give
horticulture demonstrations and identify
horticultural products. In fact, during the
week contests were held in both these
Wednesday was tour day. The
horticulture learning experiences were a
visit to Pinebay U-Pick Farm, which deals
in fruits and ornamentals and to a large
sweet corn muck farm. The recreation
portion took place at Wild Waters of
As one can readily see the entire
Institute was made possible through the
efforts of a fairly large team. In addition
to the instructors, we had a lot of
interaction with the Camp Ocala staff
They helped us with recreation,
swimming, cooking, KP, and other camp
activities. Several other adults were there
to assist with camp registration, discipline,
I wish to thank all who helped with
the 1989 Institute, and especially Tom
Greenwalt (4H), Kathleen Ruppert (OH),
Linda Landrum (Volusia Ext. Hort.), and
Eleanor Foerster (Osceola Ext. Hort.), for
Financial support for the Institute came
mostly from camper registration fees, but
we also received funds from Zellwin
Farms and the Florida 4H Foundation.
Evaluations turned in by campers
indicate that the 1989 4H Horticulture
Institute was successful in its objective of
bringing 4 H'ers who have a mutual
interest in learning more about plants and
horticulture, together for a week of fun,
learn, and return.
(Stephens, Vegetarian 89-07)
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