IJE2l A VEGETARIAN NEWSLETTER
A Vegetable Crops Extension Publication University of Florida
Vegetarian 03-05 Institute of Food and Agricultural Sciences
May 2003 Cooperative Extension Service
(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.)
Vegetarian Archive Vegetarian index
L Print Version
* Breaking the TYLCV Cycle -Lessons Learned
* Evaluation of Several Collard Varieties for Summer Production in North Florida 2003-02
* Evaluation of Cultural Practices for Summer Collard Production 2003-01
List of Extension Vegetable Crops Specialists
UPCOMING EVENTS CALENDAR
Various Extension Events in South Florida. Contact Gene McAvoy at 674-4092
116th Florida State Horticultural Society. Sheraton World Resort Hotel International Drive Orlando, Fla. June 8-10, 2003.
Methyl Bromide Alternatives Field Day. NFREC-Suwannee Valley, Live Oak, FL. May 8, 2003 9am-11am. For more
information, contact Karen Hancock at 386-362-1725 or KHancock@ifas.ufl.edu.
Twilight Field Day. NFREC-Suwannee Valley, Live Oak, FL. May 29, 2003. For more information, contact Karen Hancock at 386-
362-1725 or KHancock@ifas.ufl.edu .
CEU Day at Florida State Horticultural Society. June 9, 2003, 7:30 am 4:30 pm
71st Annual Meeting and Convention of the Florida Seed Association. Don CeSar Resort and Spa, St. Petersburg, FL. June
18-20, 2003. For more information, contact Jack Oswald at 850-482-8241and for Hotel Reservations, call the hotel at 727-360-1881.
Also visit www.floridaseed.org .
49th Conference of the InterAmerican Society for Tropical Horticulture. Fortaleza, Brazil, Aug. 31- Sept. 5, 2003.
ISHS International Symposium on Protected Culture in a Mild-Winter Climate. Renaissance WorldGate Hotel Kissimmee,
Fla. March 23-27, 2004. Contact: Daniel Cantliffe at firstname.lastname@example.org
BREAKING THE TYLCV CYCLE -LESSONS LEARNED
This season has been a prime example of what can happen when Tomato Yellow Leaf Curl Virus (TYLCV) infected tomato crops are
not destroyed in a timely manner or crops are picked longer than normal. In the past, this issue has often focused on U-picks and/or poor
end-of-season management, but these are not the only problems. Planted earlier and often picked later, grape tomatoes are essentially
bridging the gap between the fall and spring crops in west central Florida. The little crop or host-free period we thought we had has been
reduced or essentially lost by overwintering crops and the lack of a good killing freeze. Some growers thought this winter's temperatures
were low enough to destroy the crop on their own but this was not always the case. These growers realized this when they started
seeing regrowth in plants that were "frozen" but never herbicided or burned. This year, some "fall" grape tomatoes effectively served as
a "winter nursery" for virus and silverleaf whitefly (SWF). The result was devastating for adjoining spring tomato fields, with virus
percentages between 50 and almost 100% in some blocks! Unfortunately, the domino effect begins, with the "circle of influence"
widening as the season progresses. Growers are urged to not let their guard down and at the same time, consider their neighbors. When
picking crops such as cherry and grape tomatoes where the harvest interval is shortened and thus the choice of chemicals may be fewer,
at least consider applications of an oil. Especially, if virus is present to help reduce adult populations for the sake of your own
surrounding fields as well as your neighbors. Although whitefly numbers this spring have not been as high as in some seasons in the
past, apparently many were "dirty" coming in from virus infected fields, thus increasing primary infection or transmission. Although
chemical applications for control of adult SWF early in the season in fields treated with Admire or Platinum has typically not been
recommended, growers who know they are close to old, virus laden fields may see a benefit from an adulticide. If you are in this
situation, at least choose materials in different chemical classes from Admire and Platinum to minimize resistance problems. Growers
have also been heard questioning the value of an IPM scouting program if they are having to spray for whitefly twice weekly anyway.
Keep in mind that your scout is looking at other pests in addition to SWF. Remember in the past when spraying for SWF increased,
problems with other pests sometimes increased and the pest spectrum changed as levels of beneficial and predators were reduced.
One of the benefits of scouting is improvement in the timing of sprays and thus increased efficacy. Another benefit is being part of a
network so that you know what's going on in other parts of your production area. Additional information on breaking the cycle can be
found in the 2002 Tomato Institute Proceedings available online at the SWFREC website at
http://www.imok.ufl.edu/veghort/docs/tom inst 2002 091202.pdf.
Fig. 1. Typical symptoms of TYLCV. Fig. 2. SWF adult. (Credit: Scott Bauer, USDA)
(P.R. Gilreath, Manatee County -Vegetarian 03-05)
EVALUATION OF SEVERAL COLLARD VARIETIES
FOR SUMMER PRODUCTION IN NORTH FLORIDA 2003-02
This observational trial was conducted to evaluate eight collard varieties for their production potential during the late spring and early
summer period. Collard production in North Florida normally ends in the spring due to high temperatures and begins again in the early
fall, leaving the summer period of June September without production. Market demands are still good through the summer months if
the right varieties and production practices could be used to provide good quality collards.
Material and Methods
Observational plots were established in a Lakeland fine sand at the North Florida Research and Education Center Suwannee Valley,
near Live Oak, FL. Plots were established after fertilizing the soil with 500 Ibs/A of 13-4-13 (N-P205-K20). The soil was bedded,
pressed, and fumigated prior to covering with black polyethylene mulch. Drip tape (Roberts RoDrip) was applied to the bed center in a
1-inch deep groove in the bed top as the mulch was laid. The black plastic mulch was painted white using a CO2 propellant sprayer. The
paint was a mixture of white latex paint and water (1:5 mixture). The white paint was used to reduce the bed temperature to benefit the
collard crop during the high temperatures of May-July. A white-on-black plastic mulch could also be used if available.
Collard transplants of eight varieties (Table 1) were planted in single plots on May 15, 2002. Two rows per bed were planted with plant
spacing of 12 inches in each row. Each plot was planted with 28 transplants. Harvests were made on June 14, and July 25. Harvests
were conducted by removing individual leaves and stems of marketable size. Total harvested collard weight per plot was taken at each
harvest. In addition, on June 14, each variety sample was processed at a commercial fresh cut location. The final marketable cut
collard yield per plot was measured and recorded. The grower also gave a texture rating of 1-10 for each plot, with 1 = too tender and
10 = best crisp texture.
Results and Discussion
In general, the collard varieties grew well during the spring season. Top Bunch (Fig. 1) produced 25 Ibs/plot (able 1) followed by Blue
Max (21 Ibs/plot) (Fig. 2), and Flash (20 Ibs/plot) (Fg.). The variety, Vates, only produced 15 Ibs/plot. After all samples were graded
and evaluated at the processing facility, only Top Bunch and Blue Max retained over 20 Ibs/plot of marketable yield. A texture rating
was also given by the grower. These ratings were based on the acceptability as a cut green. If greens are too tender, a lower rating was
given. Blue Max was given the highest rating in this test.
Fig 1. Top Bunch collard. Fig 2. Blue Max collard. Fig 3. Flash collard.
These plots were maintained during June and harvested again on July 25. Top yields over the mid summer period were found in Top
Bunch and Blue Max. Poor summer yields were found in Vates and Morris Heading.Blue Max leaf structure was different than other
cultivars in that it has a very small petiole. This results in large leaves and seemed to be an advantage in the early season. Leaf quality
for the July 25 harvest of Blue Max was poor due to excessive toughness. The overall evaluation of the varieties for the observational
study indicated Top Bunch was the best choice overall for late spring and summer production, but Flash also showed promise.
Table 1. Yield and quality of eight collard varieties produced during the late spring and summer of 2002 in North Florida.
June 14 July 25
Collard Varieties Yield (Ibs/plot) Texture Total Yield
Totalz Marketabley Rating x (1-10) (Ibs/plot)
Champion 18 16.0 6 15.0
Blue Max 21 20.8 10 20.0
Heavy Crop 17 16.8 7 16.5
Flash 20 18.5 7 17.5
Georgia 19 15.1 9 17.0
Top Bunch 25 21.7 8 23.0
Vates 15 13.1 9 11.0
Morris Heading 19 18.0 9 10.0
z Total yield was the weight of harvested leaves.
Y Final marketable yield was weight of cut greens after commercial machine chopping.
x Texture rating was 1-10; 1 = too tender, 10 = best texture (crisp).
(B. Hochmuth, S. Stapleton, Multi Co. Ext. Agts., NFREC-SV, Ad. Townsend, Lake City, FL, S. Olson -Vegetarian 03-05)
EVALUATION OF CULTURAL PRACTICES FOR SUMMER
COLLARD PRODUCTION 2003-01
The production of collards has been important to many growers in North Florida. Traditionally, collards have been produced during the
fall, winter, and spring season due to the cool season nature of the crop. However, year round demand exists for collards, especially for
new cut and bagged collards. This trial was conducted to evaluate various cultural practices for extending the collard season into the
summer and early fall.
This trial evaluated three cultural practices:
1. un-mulched bed culture with drip irrigation (Fig. 1)
2. white-on-black mulched bed culture with drip irrigation (Fg. 1)
3. soilless lay-flat bag culture under an open shade structure (50% shade). Fig. 2)
Field grown (bare root) Champion collard transplants were used in all plots. Transplants were established on May 24, 2002. Field plots
were irrigated and fertigated via drip tape. The irrigation schedule was set to maintain a soil water tension of 8-12 centibars at a depth of
12 inches. The fertilizer program for the field plots included 500 Ibs of 13-4-13 per acre incorporated into the bed prior to
transplanting. The fertigation schedule was weekly at the rate of 2.0 Ibs/A/day of nitrogen and potash beginning two weeks after
transplanting. The shade house, soilless culture system was set to follow the typical recommendations used to produce greenhouse
vegetable crops in perlite bag culture. The nutrient solution was set for 150 ppm of N and K during the entire season. The same plant
spacings were used in all cultural systems. Plots were harvested on July 25. The marketable yield per plant in the three systems was:
1. un-mulched plots = 0.38 Ibs/plant
2. mulched plots = 0.40 Ibs/plant
3. shade house, soilless culture = 0.69 Ibs/plant
The yield for the shade house, soilless culture plots (Fig.) was nearly twice the yield of both field systems. There was essentially no
difference in the mulched or un-mulched systems. In addition, the shade house, soilless system could have been harvested one week
earlier than the field plots. A drawback of the soilless system used (lay-flat bag culture) include the difficulty in keeping the plants upright
during high winds. A different soilless system with a string support system may be necessary.
In summary, this trial indicates great potential for producing summer collards in North Florida by using an open shade structure and
soilless production system. More research is needed to refine the cultural practices and economics of this practice.
Fig. 1. Mulched and un-mulched field
bed culture after harvest.
Fig. 2. Soilless lay-flat bag culture under
an open shade structure.
Fig. 3. Harvesting soilless lay-flat bag
(B. Hochmuth, Multi Co. Ext. Agt, NFREC-SV -Vegetarian 03-05)
Extension Vegetable Crops Specialists
Daniel J. Cantliffe
Professor and Chairman
Assistant Professor, strawberry
Assistant Professor, vegetable production
Elizabeth M. Lamb
Assistant Professor, production
Assistant Professor, soils
Donald N. Maynard
Stephen M. Olson
Professor, small farms
Mark A. Ritenour
Assistant Professor, postharvest
Ronald W. Rice
Assistant Professor, nutrition
Steven A. Sargent
Professor and APRIL EDITOR, postharvest
Assistant Professor, vegetable nutrition
William M. Stall
Professor, weed control
James M. Stephens (retired)
Professor, vegetable gardening
Charles S. Vavrina
James M. White
Associate Professor, organic farming
University of Florida
Institute of Food and Agricultural Sciences
Horticultural Sciences Department
Florida Cooperative Extension Service
North Florida Research and Education Center Suwannee Valley
Gulf Coast Research and Education Center Dover
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