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record of the Institute for Food and
Agricultural Sciences and should be
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the Institute and its staff. Current IFAS
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Copyright 2005, Board of Trustees, University
-J WATERMELON FIELD DAY
AUKRIUULTUWAL KESEAKUH:U'ENT F;;EeBR-
/- C UNIVERSITY OF FLORIDA, IFAS
June 1, 1977
Jackson Haddox, Lake County Extension Director, Moderator
Welcoming Comments J. Mr- Crali, Director, Agricultural
Research Center, Leesburg
.Discussions of Current Research
W. C. Adlerz, Entomologist
Rindworm control on watermelon
Pickleworm control on summer squash
Mole cricket control in cucurbits
D. L. Hopkins, Associate Plant Pathologist
Watermelon disease control with fungicides
Control of wilt on 'old' land
G. W. Elmstrom, Associate Horticulturist and Chairman of
Watermelon Field Day
Variety evaluation watermelon, cantaloupe, cucumber,
Chemical weed control in watermelon
Watermelon sugar analysis
G. Brinen, Graduate Student, Gainesville
Spacing, mulch, and fertilizer studies on watermelon
D. Cantliffe, Associate Horticulturist, Gainesville
Growth regulator studies with watermelon
J. M. Crall, Plant Pathologist and Center Director
Watermelon breeding topics including evaluation of
Fla. 77-1, improved wilt resistance in commercial
varieties, short internodes and small fruit size
Biological control of fusarium wilt
Refreshments (Courtesy of Foremost Fertilizer Company)
Tour of Research Plots, Laurence Sistrunk, Assistant County
Leesburg ARC Research Report WG77-2 i u i
l, Control of Fusarium wilt on "old" land. (Hopkins & Elmstrom)
Purpose: To evaluate several fumigants for the control of water-
melon Fusarium wilt and to evaluate different methods of appli-
cation of the fumigants.
Date of Planting: March 7, 1977.
Varieties: Florida Giant (wilt susceptible), Crimson Sweet
(moderately resistant), and Calhoun Gray (highly resistant).
Procedure: Smite treatments were applied with a Gandy spreader,
either before or after bedding, and incorporated with a rotovator.
Beds were formed or reformed within 2 hrs of the application of
Smite. All other fumigants were applied with a pressure fumigation
rig (John Blue). Chisels were on an 8-inch spacing. Beds were
formed, or reformed, immediately after fumigation. After all
treatments were applied the bed surface was sealed with approxi-
mately 0.5 inch of overhead irrigation.
Results: 1977. Losses to wilt prior to thinning are shown in
the following table. Smite and Vorlex provided the best control
of seedling wilt. Vorlex appeared most effective when applied
as a broadcast or 6-ft. band prior to bedding. Results of the
test are not complete.
% loss to wilt at
Rate (amt. thinning
Treatment1 ai/acre) FGz CS2 CG2
A. Na 055 30 gal. 66 17 17
B, Na 055 40 gal. 30 6 6
C. Vorlex 30 gal. 18 8 8
D. Vorlex 40 gal. 22 3 5
E. Vorlex, 6-ft. band 40 gal. 16 6 13
F, Vorlex, 6-ft. after bedding 40 gal. 39 9 8
G. Vorlex, after bedding 40 gal. 18 9 9
H. Smite 15G 30 lbs. 1 2 2
I. Smite 15G, after bedding 30 lbs. 16 5 6
J. Vapam 50 gal. 49 15 12
K. Vapam 100 gal. 39 12 7
L. Telone C-17 25 gal. 40 24 30
M. Telone C-17 35 gal. 40 9 15
N. Untreated 71 36 40
1 Treatments were applied broadcast prior to bedding except where
2 FG = Florida Giant; CS = Crimson Sweet; and CG = Calhoun Gray.
1976. Vorlex and Smite provided effective control of Fusarium
wilt in Crimson Sweet and Calhoun Gray, when the fumigants were
applied to 6-ft. bands or were broadcast. Thirty inch band
treatments were not effective. Results are given in the
t % wilt in
Smite, 40 lbs.
Vorlex, 30 gal.
Na 060, 30 gal.
Smite, 30 lbs.
Smite, 60 lbs.
Smite, 30 lbs., 6-ft. band
Na 061, 20 gal.
Smite, 20 lbs.
Smite, 30 lbs. 30-in. band
Vorlex, 30 gal., 6-ft. band
Vorlex, 30 gal., 30-in. band
1 Rates are given on an ai/broadcast acre basis. Treatments were
applied broadcast prior to bedding except where noted otherwise.
2 CS = Crimson Sweet; CG = Calhoun Gray.
2. Jubilee and Charleston Grays Seed Source/Wilt Trial (Elmstrom,
Hopkins, and Crall
Purpose: To compare the relative wilt resistance of Charleston
Gray and Jubilee watermelon plants grown from seed from several
Procedure: Single-row plots were planted March 3 in a field
thoroughly infested with Fusarium wilt and in a field that was
last planted to watermelons in 1971. Seed was also planted in
the greenhouse in soil artificially infested with the Fusarium
1. Charleston Gray Breeders Seed
2. Charleston Gray Asgrow
3. Charleston Gray Burrell
4. Charleston Gray Harris
5. Charleston Gray Herbst
6. Charleston Gray Hollar
7. Charleston Gray Keystone
8. Charleston Gray Niagara
9. Charleston Gray Northrup, King
10. Charleston Gray Burpee
11. Jubilee Breeders Seed
12. Jubilee Foundation Seed
Jubilee Ferry Morse
Jubilee Northrup, King
3. Watermelon Pre-emergence Herbicide Trial (Elmstrom)
Purpose: To evaluate various materials for pre-emergence control
of weeds in watermelon plots.
Procedure: Calhoun Gray watermelon seed was planted March 8.
The following treatments were either pre-plant incorporated (ppi)
or surface applied prior to crop or weed emergence (pes):
Number Treatment lb a.i./acre Application Seedbed
1 Amex 2.0 pes Stale
2 Amex 2.0 ppi Stale
3 Amex 2.0 pes Fresh
4 Amex 2.0 ppi Fresh
5 Amex 4.0 pes Fresh
6 Amex 4.0 ppi Fresh
7 Surflan 0.5 pes Fresh
8 Surflan 0.75 pes Fresh
9 Surflan 1.00 pes Fresh
10 Sonolan 0.75 pes Fresh
11 Sonolan 1.00 pes Fresh
12 Sonolan 2.00 pes Fresh
13 Prowl 0.75 pes Fresh
14 Prowl 1.00 pes Fresh
15 Prowl 2.00 pes Fresh
16 Amex 2.00 pes Fresh
17 Amex 4.0 pes Fresh
18 Amex 4.0 pes Stale
19 Amex 4.0 ppi Stale
20 Hoed check Fresh
21 Unhoed check Stale
22 Unhoed check Fresh
Results: Amex has shown promise for several years and registration
on watermelon was nearly ready. However, AmChem, manufacturers
of Amex, has decided not to continue with development of Amex.
Sonolan and Prowl were phytotoxic to watermelon seedlings at
rates necessary to provide adequate weed control.
4. Contact Herbicides for Weed Control in Watermelon (Elmstrom)
purpose : To evaluate the use of paraquat, a contact herbicide,
for preemergence weed control and as a directed spray.
Procedure: Charleston Gray watermelons were planted March 8.
Paraquat was applied prior to planting and just prior to crop
emergence, a third application was made to one half the plants
9 days after crop emergence. Watermelon plants were covered
with 'Hotcaps' to protect them from paraquat injury.
Results: In this trial weed seed germination and crop germination
occurred about the same time. Therefore, the preemergence paraquat
application was of little benefit. Excellent control of weeds was
obtained when paraquat was used on beds with protection provided
for the watermelon seedling.
5. Watermelon Breeding (Crall)
A major change in the watermelon breeding program here was initiated
in 1961 when the first crosses were made to combine the high-type
resistance to Fusarium wilt found in Texas W5, Summit, Calhoun
Gray, Louisiana Queen, and perhaps some other varieties, with
anthracnose resistance (Race 1) and other characters desirable in
a high quality shipping-type watermelon. Smokylee, which was
released in 1971, was developed from this program. Other selections,
in advanced generations from similar crosses, are being evaluated
for future release. Most promising are several related lines that
have been in grower and regional tests since 1975. Florida 75-1,
a Dixie Queen type, was highly rated by many test growers in 1975
and 1976, but has been replaced in most test plantings this year
by Florida 77-1 and Florida 77-2, which are similar in appearance
but believed to be superior in important characteristics to
Florida 75-1. Other selections with large fruits (both round and
long shapes) from this program are also being evaluated.
In 1962, an intense red flesh color from certain Peacock lines was
incorporated into our breeding program. This character, especially
in combination with black seeds, and crisper-firmer flesh texture
have been two of the most important improvements in many of our
breeding lines since that time and have markedly improved the cut
appearance and eating quality of the watermelon flesh. This
combination of characters, excellent eating qualities, and an
extremely tough rind are combined in our Florida 75-1 and
Florida 77-1 selections.
In 1964, because of the increased occurrence of watermelon mosaic
in commercial fields in the early 1960s, especially in south
Florida, we screened all available accessions of Citrullus
(watermelon) species from the Plant Introduction Station at
Experiment, Georgia for resistance to mosaic. Three accessions
remained free of symptoms under field conditions of general
infection. Crosses were made between them and some of our
better breeding lines, but no major program of testing and
selecting for mosaic was initiated. We still maintain several
lines from this program, with selection being made on the basis
of tolerance to mosaic infection, since no clear-cut resistance
to infection has been established.
Another major facet in our breeding program was initiated in 1969,
when crosses were made between several of our better large-fruited
lines and a number of small-fruited varieties, including New
Hampshire Midget, Sugar Baby, and several from foreign countries,
especially Japan. The aim of this part of our program is to develop
small-fruited varieties with combined resistance to Fusarium wilt
and anthracnose, deep red flesh, small black seeds, and other
desirable fruit qualities. We are seeking to develop varieties
that might be adapted to shipping in cartons, in a range of sizes
from 4 to 20 pounds. This season these lines are mostly in the
Fg or F7 generations, but none is sufficiently fixed yet to warrant
outside testing. Most promising selections include a New
Hampshire Midget type (under 5 pounds), a small Dixie Queen type
(5-10 pounds), and a Klondike type (10-20 pounds).
Greenhouse and field tests in 1971-72 and later confirmed the
suspicion that commercial seed stocks of Jubilee no longer had
the same degree of resistance to Fusarium wilt as that found in
original "breeder" seed of Jubilee. Increases of seed from
breeder stocks were made available to commercial seedsmen for
several years so that they could produce "registered" seed for
sale to growers. Growers willingly paid a premium price for
such seed because of its greater resistance to wilt, but practical
problems in the production of sufficient quantities of "registered"
grade seed have limited the success of this approach to the
problem. Two other approaches to a solution have been initiated
here. A selfing program to better fix wilt resistance in Jubilee
has been conducted since 1972 but no apparent progress has been
made by this method. However, a backcrossing program to incor-
porate the high-type wilt resistance of Smokylee and Calhoun Gray
in Jubilee and several other varieties was also started in 1972.
This is a comprehensive program that requires continued selfing,
backcrossing, and greenhouse testing in a specific sequence, but
it is perhaps the most promising method for accomplishing the
aim of getting improved wilt resistance in Jubilee and other
commercial varieties. With Jubilee we are in the fourth backcross
generation in 1977, with at least 7 or 8 backcross generations
necessary before a highly wilt resistant Jubilee type can be
In 1973 the first crosses were made between some of our better
lines and several wilt- and anthracnose-sus.ceptible short-
internode (dwarf) lines from Kentucky. We have several dwarf
lines in this year's breeding field with apparent resistance
to Fusarium wilt and anthracnose but efforts in this part of
our program have been limited.
6. Fungicide Trial (Hopkins)
Purpose: To compare fumgicides for control of fungus foliar
diseases of watermelon.
Date of Planting: March 1, 1977
Procedure: All treatments except G and H were applied weekly
beginning on May 5. Except for treatment H, they were applied
oa 100 gallons of dilute spray per acre, using.a boom-sprayer.
Rate of product per acre
Benlate + Manzate 200
CGA-48988 50W (14 day)
Difolatan 4F + THIS Veg. Mix
CC 7623 65W
CC 7781 4F
Dithane M-45 + THIS
0.5 lb. + 1.5 lbs.
10.0 lb./acre preplant incorp. +
5.0 lb./acre to surface as vines run
2.5 pts. + 2.0 pts.
2.0 lbs. + 2.0 pts.
Results: 1976. Gummy stem blight was the primary disease in the
fct area. Bravo 6F, Difolatan, and Benlate + Manzate 200 were
most effective in controlling gummy stem blight. Dithane M-45
2.iud ;!:ia'ate 200 were also effective.
1977. Results of the test are not available for the program.
Plots will be observed on the field tour.
Recommended Materials Rate (amt./acre) to harvest1
Ianeob 80% 1 1/2 2 lbs. 5
Lithane M-45 80% 1 1/2 2 lbs. 5
'.:-iz.te 200 80% 1 1/2 2 Ibs. 5
Bravo 75% or 6F 1 1/2 2 1/2 Ibs. or NTL
1 1/2 2 1/2 pts.
Difolatan 4F 2 1/2 pts. NTL
Benlate 50%2 1/4 1/2 lb. NTL
This is the minimum number of days allowed between the last
foliar application and harvest. NTL = no time limit.
2 Benlate does not control downy mildew or alternaria leaf spot.
7. hini3dworm Control Experimental Insecticides (Adlerz)
Purpose: Evaluation of chemicals not presently labeled for use
on watermelons to control rindworms. Standards: methomyl, Dipel.
Date of Planting: 1 March, 1977
Procedure: Treatments were applied weekly beginning 2 May, soon
after first fruit set. They were applied in 100 gal. of water/
acre at about 150 psi through 9 hollow cone nozzles on a 14-foot
Nudrin 90 SP
Bay NTN 6E
Bay NTN 6E
FMC 33297 3.2E
FMC 33297 3.2E
SD 43775 2.4E
SD 43775 2.4E
PP 557 2E
PP 557 2E
Nudrin 90 SP
SD 43775 2.4E
Orthene 75 SP
Results: 1976. Rindworm populations on mature melons in untreated
plots May 12 were 54% granulate cutworms, 38% cabbage loopers, and
8% tobacco budworms. Control was excellent with several materials
including SD 43775 and FMC 33297 (synthetic pyrethroids) Nudrin,
Bay NTN 9306, Orthene, Dipel, Phosvel, Lannate, and Monitor.
1977. Results not available for program. Plots will be observed
on the field tour.
8. Pickleworm Control on Squash (Adlerz)
Purpose: To compare insecticides for control of pickleworm.
Date of Planting: 9 March 1977
Variety: Burpee Hybrid Zucchini
Procedure: Treatments were applied weekly from 12 April to 3 May.
They were applied in 100 gal. of water/acre at about 150 psi.
Treatments Rate/100 gal./acre
A. Lannate L 1.8 2 qt.
B. Bay NTN 9306 6E 21 oz.
C. PP 557 2E 12.8 oz.
D. Lindane 25W 2 lb.
E. SD 43775 2.4E 5.3 oz.
F. SD 43775 2.4E 10.6 oz.
G. Imidan 70W 0.99 lb.
H. Imidan 70W 1.33 lb.
I. FMC 33297 3.2E 4 oz.
J. FMC 33297 3.2E 8 oz.
K. Furadan 10G (2 lb AI/acre, band)
Results: 1976. A test similar to this was conducted in the fall
of 1976. Early Golden Summer Crookneck and Burpee Hybrid Zucchini
squash were planted and sprayed as above. Treatments were not all
as outlined above. Zucchini was more pickleworm susceptible than
crookneck. Excellent results were obtained on zucchini with
Nudrin, Lannate, and Bay NTN 9306. SD 43775, Sevin, and Thiodan
were very good. On crookneck all these were excellent, as were
Lindane, and Imidan. FMC 33297 was not very effective.
Results 1977: There were no pickleworms to 24 May.
9. Watermelon'Mosaic (Adlerz)
Purpose: A study of factors affecting development of mosaic
disease in the field and methods for its control.
Date of Planting: These observations are made on commercial
acreage and on experimental plots designed for other purposes,
so dates of planting are not uniform.
Results: Initial spread of WMV-2 is not correlated with the
activity of any one species of aphid. Many species are capable
of transmitting the virus.
In most years at Leesburg first symptoms appear after peak aphid
flights. Mosaic development takes place during periods of
declining aphid populations and may not be extensive.
Usually mosaic development is extensive whenever winged aphid
populations are large, but the effect on the crop is severe only
when peak flights are in April. When peak aphid flights are in
May mosaic infection is usually too late to affect the crop.
The most severe outbreaks develop when winds are sustained across
primary inoculum toward uninfected plants.
The spiraea aphid develops on a wide variety of weed, ornamental,
and crop plants and at Leesburg, often comprises most of the winged
aphid population at the time of peak aphid occurrence. Numbers
large enough to cause severe outbreak usually develop on citrus.
In 1976 aphid populations were small. There was little mosaic.
In 1977 aphid populations were small, peaked in mid March.
Mosaic developed in early April and has been very severe.
Table 1. Aphids/trap/week on sticky boards at the laboratory
farm (6-foot high trap).
March April May
1 2 3 4 1 2 3 4 1 2
1974 357 37 546 87 17 91 42 26 54 13
1975 23 38 23 17 12 13 17 7 21 1
1976 16 22 19 25 18 11 17 35 17 17
1977 13 37 46 13 8 7 6 7 3 5
Mosaic incidence 1977, Ranges Z-DD, Rows 1-24
Trapping records above do not include populations of Anuraphis
middletonii-a root aphid that flies at low levels. Beginning
the first week of April, aphids trapped at ground level near
watermelon plants were 80% or more A. middletonii. We have
demonstrated the natural vectoring ability of this aphid in the
field. Daily movement by the aphid on easterly winds across
the field in the direction from infected to healthy plants
resulted in the extensive infection of 1977.
Plants on which A. middletonii has been found in Leesburg are
cudweed, horseweed, tansymustard, Florida pusley, Virginia
pepperweed, mexicantea, dog fennel, and ragweed.
10. Mole Cricket Control (Adlerz)
Purpose: Evaluation of applicator formulated bran-molasses
baits for mole cricket control.
Date of Planting: 1976
Procedure: Baits were formulated with wettable powder insecticides,
wheat bran, and 1/1 water-molasses at 1.5 qt/10 Ibs wheat bran.
Applications were usually of 5% baits at 40 lbs/acre.
Results: Good results were obtained with chlordane,'lindane,.
Phosvel, Imidan, Methoinyl, Orthene, Sevin, and-Dylox.
11. Watermelon Variety Trial (Elmstrom)
Purpose: To compare promising breeding lines and new varieties
with standard commercial varieties.
Procedure: Two-row plots in randomized blocks with 4 replications
were planted March 8,
1. Charleston Gray 10. Charleston Gray #5
2. Calhoun Gray 11. Charleston 76
3. Crimson Sweet 12. Dixie Queen
4. Jubilee 13. Fla 77-.1- ..
5. Allsweet 14. Fla 77-2
6. Smokylee 15. Fla 77-3
7. Yellow Baby 16. Fla 75-1
8. Top Yield Fl 17. Florida Giant
9. Charleston Gray #133
1. BJ 82L1 7. NC 75-H21
2. Dixie Queen Fl 8. NC .76-H8
3. Sugar Doll 9. NC 76-H23
4. Sweetmeat II WR 10. Sugar Bush
5. Ark 75-11N 11. Yellow Doll
6. NC 75-H18
Results: See Watermelon Varieties for Florida, Leesburg ARC
Research Report WG77-1 and Severity of Bacterial Rind Necrosis in
Watermelon Cultivars in Florida, Florida State Horticultural
Society Proceedings 87:184-187 (1974).
Old standard watermelon varieties and many new inbred and F1 varieties
have been evaluated. With the exception of 'Yellow Baby' all F1
hybrids tested were highly susceptible to Fusarium wilt and planting
in Florida is not recommended. The hybrids included in tests were
'Top Yield', 'Sweetmeat', 'Triple Sweet Seedless', 'Tri X-313',
'Family Fun', 'Royal Charleston', and 'Summer Festival'. Other
varieties which lack wilt resistance include 'Garrisonian', 'Florida
Giant', 'Petite Sweet', 'Klondike Blue Ribbon', and 'Peacock'.
Varieties with a high level of resistance to Fusarium wilt include
'Louisiana Queen', 'Summit', 'Calhoun Gray', and 'Smokylee'.
However, internal quality of 'Louisiana Queen', and 'Summit' is
poor. Under optimum conditions 'Calhoun Gray' produces good quality
fruit but moderate stress conditions result in poor fruit quality.
'Smokylee' fruit have excellent flesh quality including high sugar
levels and-fine texture but white seed, poor seedling vigor,
susceptibility to sunburn, and an internal flesh breakdown with
excessive rainfall have limited commercial plantings. 'Allsweet'
has a level of wilt resistance comparable to that of 'Crimson Sweet'
as well as excellent internal appearance and quality; however, it
matures too late to be acceptable by most Florida growers. 'Sweet
Princess' fruit have a somewhat higher quality than 'Charleston
Gray' but yield is generally lower. Seed of 'Sweet Princess' are
quite small and it has been difficult to obtain an early uniform
stand. 'lopride' a recently-released variety from Iowa has a high
level of resistance to Fusarium wilt but ripening in Florida has
been uneven and quality generally has been poor.
12. Cantaloupe Variety Trial (Elmstrom)
Purpose: To compare promising breeding lines and new varieties
with standard commercial varieties.
Procedure: Single-row plots in randomized blocks with 3 repli-
cations were planted March 9-11.
1. Planters Jumbo
2. AC 67-17
3. AC 67-59
4. AC 68-52
5. AC 68-57
6. AC 70-154
7. Fla 6-28L Fl
8. VBL 63-4-M1-18-M8
Dixie Jumbo Fl
Results: Gulfcoast, Edisto 47, Planters Jumbo, Samson, and Saticoy
cantaloupe have done well in field trials at the Agricultural
Research Center, Leesburg and are recommended. Planters Jumbo has
the highest level of foliar disease resistance; however, internal
quality is poor. Saticoy, Samson, and Supermarket are three hybrid
varieties which have excellent internal quality even under less
than optimum field conditions. These hybrids do not have the level
of foliar disease resistance found in Planters Jumbo.
13. Improvement of fruit set, development, size and shape of watermelon
(Cantliffe and Elmstrom)
Purpose: To increase the number of ovaries per plant that develop
into marketable fruit with concentrated set.
Procedure: Crimson Sweet Watermelon seed was planted March 3. The
following treatments were applied during early fruit set or after
at least one fruit per plant had developed to approximately 1-2 pounds.
Treatment Time of application
2. Chlorflurenol (100 ppm) Medium
3. NAA (1000 ppm) (xl) Medium
4. NAA (100 ppm) (x4) Early
5. NAA (1000 ppm)-l day-Chlorflurenol (100 ppm) Medium
6. Chlorflurenol (100 ppm-1 day-NAA (1000 ppm) Medium
7. Chlorflurenol (100 ppm)-l day-NAA (100 ppm) (x4) Early
8. NAA (100 ppm)-l day-Chlorflurenol (100 ppm)-NAA
(100 ppm) (x3) Early
L4. Watermelon Spacing, Mulch, and Fertilizer Trial (Brinen, Locascio,
Purpose: To determine the interrelationship between row width
and inrow spacing of 'Charleston Gray' watermelon grown with
and without black polyethylene mulch at two fertilizer rates.
Procedure: Seeds were planted March 3 with the treatment factors
Fertilizer Rate Polyethylene Mulch
1. 750 Ib/A (12-16-16) 1. Mulch
2. 1500 lb/A (12-16-16) 2. No mulch
Row Width Inrow Spacing
1. 5 ft. 1. 2 ft.
2. 10 ft. 2. 4 ft.
3. 15 ft. 3. 8 ft.
Results: Incomplete. Date are being taken on early plant weight,
tissue, and soil composition, and fruit yield.
L5. Biological Control of Fusarium Wilt (Crall)
Work was initiated in 1974 to evaluate several methods of control
of Fusarium wilt of watermelon by use of biological agents. No
effect on wilt occurrence was found with soil amendments of
pulverized pine needles or pine bark. In 1976 there was a slight,
but significant, reduction in the incidence of wilt after addition
to field plots of inoculum of a Trichoderma species. Results of
this year's trial are incomplete at this time.