\ . f(ACMl~G lllS[AACH la Tl~SIOJ\I INSTITUTE OF FOOO ANO AGRICULTURAL SCIENCES UNIVERSITY OF FLORIOA FLORI CA COOPERATIVE EXTENSION SERVICE VEGETARIAN A Ve8etable Crops Extension Publication Ve 0 elablc Crops Department • 1255 H~PP • Gainesville. FL 32611 • rrelephone 392 -2134 Vegetarian 88-06 June 15,1988 Contents I. NOI'ES OF INTEREST A. Vegetable Crops calendar. B. Publications II. CI:M4ERCIAL VffiETABIES A. Leaf silvering of Squash. B. More Pepper Nitrogen Pepper Demonstrations. c. Otl.orination of Dlrnp Tanks. III. VffiETABLE GARDENING A. Disease Resistance in Florida Garden Tomatoes. Note: Anyone is free to use the information in this newsletter. Whenever possible, please give credit to the authors . '!he purpose of trade names in this publication is solely for the purpose of providing information and does not necessarily constitute a recormnendation of the product. The In st i tute of F ood and Agri~ ult ural Sciences is an Equal Empl oym ent Opportun ity· Affirmat ive Actio n Employer author ized to provide research, educa tio nal information and othe r serv ices only to individuals an d institut ions that function w ithout regard to race , color, sex, or nat ional or igin. ,.....nnn rn ATl\lf"' r v-rr•ir.,nu u1 nnv la t A t""'ntn • tt Tt tnr- A Un 11n••r- C'f"\n•1r na1r ~ <="T/\T~ ('\~ ~· ru ;un/\ IS:O~ I IN l\/ 1:s::l~tTY nF
Transcript
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f(ACMl~G lllS[AACH la Tl~SIOJ\I
INSTITUTE OF FOOO ANO AGRICULTURAL SCIENCES
UNIVERSITY OF FLORIOA
FLORI CA COOPERATIVE
EXTENSION SERVICE
VEGETARIAN A Ve8etable Crops Extension Publication Ve0elablc Crops Department • 1255 H~PP • Gainesville. FL 32611 • rrelephone 392-2134
Vegetarian 88-06 June 15,1988
Contents
I. NOI'ES OF INTEREST
A. Vegetable Crops calendar.
B. Publications
II. CI:M4ERCIAL VffiETABIES
A. Leaf silvering of Squash.
B. More Pepper Nitrogen Pepper Demonstrations.
c. Otl.orination of Dlrnp Tanks.
III. VffiETABLE GARDENING
A. Disease Resistance in Florida Garden Tomatoes.
Note: Anyone is free to use the information in this newsletter. Whenever possible, please give credit to the authors .
'!he purpose of trade names in this publication is solely for the purpose of providing information and does not necessarily constitute a recormnendation of the product.
The Inst i tute of F ood and Agri~ult ural Sciences is an Equal Empl oym ent Opportun ity· Affirmat ive Actio n Employer author ized to provide research, educa tio nal information and othe r serv ices only to individuals an d institut ions that function w ithout regard to race , color, sex, or nat ional or igin.
,.....nnn rn ATl\lf"' r v-rr•ir.,nu u1 nnv la t A t""'ntn • tt Tt tnr- A Un 11n••r- C'f"\n•1r na1r ~ <="T/\T~ ('\~ ~· ru ;un/\ IS:O~ I IN l\/ 1:s::l~tTY nF
I. mIES OF INl'ERFb"'"l'
A. Vegetable Crg:xs calen:lar .
June 20- 24, 1988. 4-H Horticulture Institute, canq;> Clover leaf. (Contact Jim Stephens) .
June 21 , 1988. Vegetable Twilight Field Day. Live oak Agricultural Research and F.ducation center, Live oak, Fl. from 5:00 to 8:00 IM. (Contact George Hochmuth).
July 26-27, 1988. 4-H State Congress , Vegetable (Horticulture) Contest and career Exploration, Gainesville . (Contact Jim Stephens).
September 27, 1988. Florida To.ma.to Institute . Ritz Carl ton Hotel, Naples, FL (Contact W. M. stall).
october 27, 1988. Florida Pepper Institute: Southwest Florida Research & F.ducation center, Dmrckalee . (Contact D. N. Maynard).
B. Publications.
Clark, G. A., c. D. Stanley, and A. G. Smajstrla . 1988 . Microirrigation on mulched bed systems : Conp)nents, System capacities, and Management. Univ. Fla . Coop. Ext . Serv. circ . 245 .
Muskmelon Production Guide for Florida . 1988 Univ . Fla. Coop. Ext. Serv . Circ. 122C.
Shuler, K. D. 1988. "SUper sweet " sweet Corn Cultivar Trial Boynton Beach, Florida, Winter 1987- 88. Palm Beach County
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Extension Report 1988-1.
Maynard, D. N. and Gilreath, P. R. , 1988. Plmpkin Variety E'valuation summer/Fall 1987 . Bradenton GCREC Research Report BRAl.988-6.
Howe, T . K. and Waters, W. E., 1988. Bell Pepper Variety Trial for Immature (Green) and Mature (Colored) Harvest, Spring 1987. Bradenton GCREC Research Report BRA1988-5.
Howe, T. K. and Waters, W. E., 1988. sweet Corn Variety Trial -SUpersweets, Spring 1987 . Bradenton GCREC Research Report BRAl-988- 4.
Engelhani, Arthur W. , Woltz, s. s. and J . P . Jones, 1988. The Control of Fusaritm1 Wilt with the Integrated Lime (pH), Nitra te-N, Chemotherapy System . Bradenton GrnEC Research Report BRAl.988- 3.
Engelhani, Arthur w., 1988. Control of Bot:rytis and the Influence of Moisture and Terrperature on Disease Occurrence. Bradenton GCREC Research Report BRA1988- 2 .
Engelhani, A. w., Jones, J. P., Woltz, s . s., ovennan, A. J ., 1988. FUsaritm1 Wilt: Papers from the University of Florida Research centers Related to the Development of the Florida System of Control on Toma.toes and Onlarnentals. Bradenton GCREC Research Report BRA1988-8 .
A. I.eaf silyerirg of squash.
In the past several years, a corxtition of squash has appeared in south Florida , commonly known
as leaf silvering. 'Ihis condition is also foun:i in Israel.
Dr. Harry Paris, Dept. of Vegetable Crops, Agricultural Research Organization, Nerve Ya'ar Experiment Station, Israel, has published an article on leaf silvering (can. J. Plant Sci. 67:593-598).
Dr. Paris also spent a year on sabbatical in Florida in 1986-87. From this article several phenomenon of this disorder is described. He states that leaf silvering is a physiological disorder. In Israel the disorder is seen in late sunnner and fall crops.
Silvering is expressed in and parallel to leaf veins, except in severe cases, when it encompasses the entire leaf. Silver mottling is expressed as patches in the axes of leaf veins. In both conditions neither appears early in plant development. Also, if a leaf has the condition, it will remain so.
'Ibey are different in that in silver mottling, when the condition appears on one leaf, the following leaves, when they emerge, will have the condition. Silvering of a leaf, however, does not preclude later leaves from being green. Anatomically, both the genetically detennined silver-mottled leaves and the physiological leaf silvering are attributable to the lack of close contact between palisade cells and contact between palisade cells and the epidennis, resulting in air spaces. Silvermottled leaves have been reported to reflect more light than nonmottled (green) leaves.
Dr. Paris reported in his paper that although the incidence of silvering was not affected,
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the severity of the silvering was significantly affected by soil moisture. The lower the moisture, the greater the severity. He also speculated that silvering may be interpreted as a plant defensive response against desiccation. '!his theory corresponds with the greater incidence of the problem during their no-rain periods of late surmner and fall.
The incidence of silvering during the "drier" months of the year also corresponds to Florida. 'Ihe initiation of the condition probably occurs in the bud and becomes pronounced as the leaf expands. We in Florida and those in Israel have not yet identified the factors necessary for silvering to be induced.
Although many speculate on a virus, no isolations have been seen after numerous attempts. Air pollution and insect feeding have also been raised as possible answers. Both of these are being studied, but as yet, no correlation as been found.
'!here is considerable ongoing work to isolate the cause of the problem. If any correlations to e.zwironmental or biological factors are made by anyone in the observations of the leaf silvering cx::currences, I would appreciate being infonned. If we can finally isolate the cause, then a control can be worked on.
(stall, Veg. 88-06)
B. }ok)re pepper nitrogen de:tDnst:rations.
'Ihis past winter, Ken Shuler, Fhyllis Gilreath, and I continued our field demonstrations on pepper fertilizer management and soiltest calibration. our objectives
are to dem::mstrate !FAS nitrogen and potassiurn fertilizer recomrrwarrlations and to collect data for calibrating our potassiurn soil test procedure.
'Ihis article reports on the effects of the nitrogen treatments on pepper yield at Boynton Beach (DIBois Fanns). In this study, the grower appl ied his basic (starter mix) of fertilizer (800 lb. per acre of 6-8 - 6) in shoulder barrls on August 28. We then applied various combinations of nitrogen and potassiurn to the center band of our plots. 'Ibtal nitrogen amounts were 160, 220, 280, and 336 lb. of N per acre. '!he 336 lb. per acre was the grower rate . Potassium treatments ranged from 48 to 416 lb. of K2o per acre.
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Plots were seeded Septent>er 3, 1987 with 'P.R. 7594' pepper hybrid and were harvested 6 times fran Nov. 30 through Feb. 18. Total marketable pepper yields for the nitrogen main effects are presented in table 1. 'Ihe first 3 nitrogen treatments were arranc:Jed with the potass iurn rates in a factorial experiment. '!he results sho.ved no significant differences anoIXJ nitrogen rates for total marketable yield. Presently our fertilizer recorrnnenjations for nitrogen are set at 160 lb. N per acre for three harvests. We are presently analyzing data from the pepper grading and storage tests that were corrlucted on the fruit.
Table 1. Response of pepper to levels of nitrogen in a winter crop at Boynton Beach, Fl. 1988-89.
Marketable yield (25-lb ctn. oer acre) N rate Harvest date lb LA Nov. 30 Dec. 15 Dec. 29 Jan. 12 Jan. 29 Feb.18 'Ibtal
xAverage of 9 observations (3 reps; 3K2o rates). Ycanmercial fertilizer rate with 'P.R. 7594' • zcanmercial fertilizer rate with 'Early calWon::ler'.
(Hcx::hmuth, Veg. 88-06)
c. Chlorination of romp tanks.
D.mp tank chlorination is a water purification treatment. It does not disinfect the tissue of contaminated vegetables but does prevent the spread of decayproducing organisms in the water
of the en.mp tank. CUrrently, it is reconunended that chlo r ine be maintained at 100 to 150 ppm, although 50 ppn of chlorine is probably m::>re than adequate if that level is maintained.
'!he m::>St common disinfectants containing chlorine that are ncM in general use are
chlorine gas, soclium hypoc:hlorite (camrercial bleach at 10-12%), and calcium hypochlorite (chlorinated lime at about 65%). All these chlorine-containing chemicals form hypoc:hlorous acid when added to water.
Germicidal activity of chlorinated dump tanks depends upon factors such as water temperature, the amount of organic matter present, exposure time to the chlorine, and pH of the water. In the past, minor consideration has been given to these factors because most dump tanks use heated water, additional chlorine is added throughout the day to C011I)en5ate for increasing organic matter and tanks are also cleaned daily, exposure time to the chlorine is adequate, and under Florida conditions we have considered water pH to be in the 11effective 11
range. '!he use of chlorine has an
effect upon the pH of the water, deperrling on the type of chlorine used. Also, water pH is a critical factor in maintaining effective chlorine concentrations. For example:
Water pH
6.5 7.0 7.5 8.0
Cl effectiveness
90% 75% 50% 25%
For maximum effectiveness, water pH should be maintained at 6. 5 to 7.5.
We have been in contact with a water treatinent carrpany operating out of Sarasota and they have installed their system in two packinghouses in Florida. '!he basis of their system is the automatic control of water pH and the metering of chlorine (soclium hypochlorite) to maintain 150 ppm of free chlorine. Under these
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controlled conditions the level of chlorine could be lowered for an additional saving. '!heir system of pH control and metering of chlorine has reduced the daily usage of hypochlorite by one half. '!his reduction in the use of chlorine and the rrore favorable water pH should reduce the corrosiveness to equipment, lower the unpleasant cxiors of chlorine in the vicinity of the dtnnp tank, and have a favorab l e economic impact upon the packinghouse operation. More details of this system will be made available as results are obtained. Name of the company will be furnished upon request.
(Gull, Veg. 88-06)
A. Di...~se resistance in Florida ga:cden tcmatoes.
We all want to avoid spraying pesticides on our gardens if at all possib l e. However, with all the disease and insect pests we have in our warm, muggy state, we sometimes have to give the little scavengers a quick chemical kick in the rear end if we are to get any returns for our efforts.
One of the best ways to reduce the need to spray is to plant varieties of vegetables that have pest resistance, or at least tolerance, built into their genes. a.it when we look at the long list of varieties reconunended for our area , we really can't tell which ones are resistant to what. Okay, maybe we should list in our gui des the pests which these variet i es are supposed to ward off. Pl anting guides are brief and concise to avoid the appearance of textbooks and bulletins, so space is limited.
To provide more infonnation in this area I shall utilize our Vegetarian newsletter. I.et 1 s start with the big red one - the tomato. In subsequent issues we'll continue with the other vegetable varieties.Circular 104P, the Vegetable Gardening Guide is our main reference on current varietal recommerrlations . Looking at the current
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list of tomato varieties. (by the way, also known as 11cultivars 11
), we firrl the following, which are hereby described according to disease resistance. Since resistance to other pests such as insects arrl nematodes is seldom found in the tomato, we'll list only those diseases for which the varieti es are legitimately resistant.
Tomato varieties in current vegetable gardening guide (Cir. 104P)
Name Fruit type Plant type Disease resistance
Floradel large red Indet. Fus. wilt (1) ; gray leaf-spot; graywall
Tropic large red Indet. Fus. wilt (1); vert. wilt; gray leafspot; graywal l
Manalucie Large red Indet. Fus. wilt (1); F.arly blight; gray l eafspot; gray wall; leafnold
Better Boy large red Indet. Fus. wilt (1) ; verticillium wilt
Cherry Grande Small red Det. Fus. wilt {1); vert, gray leafspot; Al ternaria stem
Walter Large red Det. Fus. (1,2); gray leafspot; graywall
Floramerica large red Det. Fus . (1,2); gray leafspot; gray mold; crown rot.
Flora - Dade large red Det. Fus. ( 1, 2) i Vert. ; gray leaf spot
Duke large red Det. Fus. (1, 2) ; vert.; gray leafspot; stem alt.
Florida Basket small red Det. Gray leafspot
Florida lanai small red Det. Gray leafspot
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Name Fruit type Plant tyPe Disease resistance
Florida Petite srna.11 red Det.
Patio meditnn red Det.
Red Cherry small red Indet.
A quick glance clearly shCMS that many serious diseases of tomato are missing from the above table. Some of these include bacterial leafspot, bacterial wilt, late blight, arrl early blight. 'Ihere fore, the planting of resistant varieties will help in reducing pesticide applications, but does not eliminate them altogether.
