WATERMELON AND GRAPE INVESTIGATIONS LABORATORY
UNIVERSITY OF FLORIDA AGRICULTURAL EXPERIMENT STATIONS
Mimeo Report WGL 64-2 May 27, 1964
WATERMELON FIELD DAY PROGRAM
1:30 P. M.
Welcome to Lake County and the Watermelon Field Day. W. M. Nixon,
Assistant County Agent, Lake County.
Introduction of Visitors. J. M. Montelaro, Associate Vegetable
Crops Specialist, Florida Agricultural Extension Service, Gainesville.
Grape Studies at the Watermelon and Grape Investigations Laboratory.
J. A. Mortensen, Assistant Geneticist and L. H. Stover, Assistant
Watermelon Diseases in Florida in 1964.
Soil Fumigation Studies.
Chemical Control of Watermelon Foliar Diseases.
N. C. Schenck, Associate Plant Pathologist
Insect Problems on Watermelon in Florida in 1964.
Control Measures for Watermelon Insects.
Studies on Honeybee Pollination of Watermelon.
W. C. Adlerz, Assistant Entomologist
Compatibility of Spray Mixtures of Fungicides, Insecticides, and
N. C. Schenck and W. C. Adlerz
Studies on Fusarium Wilt of Watermelon.
Watermelon Breeding and Variety Testing.
Studies on Watermelon Nutrition.
Use of Petroleum-Base Mulch in Watermelon Production.
J. M. Crall, Plant Pathologist in Charge
Tour of Plots. Members of Staff
SUMMARIES OF EXPERIMENTAL WORK
1. Watermelon Replicated Trial (Crall)
Purpose: Comparison of Charleston Gray, Charleston Gray 133,
new variety Crimson Sweet, and most promising breeding lines.
Date of planting: March 5
1. Charleston Gray 6. Charleston Gray 133
2. Crimson Sweet 7. Fla. 63-104-2
3. VBL 60-27 8. Fla. 63-128-4
4. NC62-C2M 9. WR Peacock 132
2. Peacock-Klondike Strains (Crall)
Purpose: Comparison of 9 strains of Peacock or Klondike
varieties from several sources for adaptability to Florida
Date of planting: March 4
Preliminary observations: None of these entries is particularly
outstanding. Several are extremely susceptible to Fusarium wilt.
3. Watermelon Observational Trial (Crall)
Purpose: To observe promising breeding lines from other
Date of planting: March 4
1. NC62-C5M 6. VBL-WX11
2. NC62-C7M 7. VBL-WX12
3. VBL-W1003 8. VBL-WX13
4. VBL-WX8 9. Texas Round Gray
4. Breeding Plots (Crall)
A program was initiated in 1961 to combine the Summit-type
resistance to Fusarium wilt with anthracnose (Race 1) resistance
in a high quality shipping-type watermelon. Most promising
lines in this trial are from crosses between Charleston Gray
and Texas W-5. Other varieties used as parents in this program
are Summit, Peacock #132, Fairfax, and Jubilee. Testing of
promising lines for resistance to anthracnose and Fusarium wilt
is carried out in the greenhouse from late fall through late spring,
5 Se.orch for Cytoplasmic Male Sterility in Watermelon (Crall)
Cr-sses were made between watermelon and distant relatives of
,.atermelon in an effort to obtain a plant with sterile male but
'. .ctional female flowers. When found this character will be
incorporated into existing varieties. By use of male-sterile
p.iants, hybrid plants may be produced without the expense of
initial crosses were made in 1960. Backcresses to the Fl were
mi;-c. in 1961. No completely self-sterile plants were found in
th.- 1962 or 1963 plantings. Back crossing to individual plants
;l:h the highest percentage of pollen abnormalities is being
c,-ntinued. Additional initial crosses between commercial
watermelon varieties (Charleston Gray, Crimson Sweet, others)
and exotic watermelon plant introductions are also being made.
6, tc.c1mite Lime Ca Mg Trial (Crall)
T:ropooFe: To determine the effect of applications of dolomite,
6n^ r d lime, calcium nitrate (Pril-Cal) and magnesium sulfate
(IE-,c) on watermelon culture under conditions of low pH
.-.,0) and limiting Ca and Mg.
rCuits of previous years' trials: In 1962 there was a
.L, Lant yield response to mixed applications of dolomite and
,<."Gra~zcd lime. In 1963 yield responses to dolomite or lime were
;. ; significant, but both early and total yields of Charleston
Gray !r~re higher after applications of calcium nitrate plus
m7ai: r'ium sulfate. Concomitant with increased yields, however,
wa .-; significantt lowering of melon quality as measured by
color, flavor, and soluble solids (sugar) content.
-.eco'mmendation on liming: Where soil tests indicate acidity of
p. '5,0 or less and low levels of Ca or Mg, applications of
do*!..m:tic or high calcium lime at least six months prior to
p ,.nting are recommended. If lime applications are not made,
yield response to Ca and Mg fertilizers may be expected under
J(g, Treatments (Split plot)
Ma.n treatments (8 rows)
Dolomite at 1 ton/acre
1Hdrated lime at 1600 lbs./acre
No dolomite or lime
Sub treatments (2 rows)
Date of planting: March 4
varieties: Charleston Gray, Texas W-5
7. I-ollination Study (Adlerz)
Purpose: This experiment continues a study of effects of various
spacings and concentrations of plants on blossom concentrations
and bee concentrations. The latter are observed for subsequent
effects on fruit set.
Date of planting: March 2
Plant spacing Plants per hill
1. 6 feet 1
2. 6 feet 2
3. 3 feet 1
4. 3 feet 2
Results: Data have not been analyzed, but enough evidence has
now been obtained to show that there is a seasonal progression
of events in the development of the crop that is characteristic
of the crop, but is modified by weather and cultural practices.
The periodic fluctuations in flower production seasonally affect
the activities of bees. These activities can be altered to some
extent by changing the concentrations of blossoms in the field,
The major portion of the 1964 crop was set between May 6 and
y 10, mostly May 7-9. This occurred immediately following a
period when there were almost no female blossoms in the field.
During the setting period female flowers were large, averaging
near 24 mm. Male-female flower ratios ranged from as little
is 10/1 to as much as 75-1. Many observations of this type have
been made, but their significance has not been evaluated at
3 Search for Cytoplasmic Male Sterility in Cantaloupe (Mortensen)
Crosses were made between cantaloupes and various cantaloupe
relatives from foreign countries in an effort to obtain plants
with sterile male but functional female flowers. This male
sterility, if cytoplasmically inherited, would then be in-
corporated into existing lines of cantaloupe. Such male-sterile
lines would be used in making hybrid seed without the expense
of hand pollination.
Only 2 plants showed promise among the backcrosses grown last
year. They did not produce any male flowers after setting two
fruits each. Progenies of the 2 .plants grown this year showed
the same lack of male flowers in some plants. Unfortunately,
preliminary results indicate that this male sterility may not
be cytoplasmically inherited.
9 ntaloupe Variety Trial and Soil Fumigation (Crall)
Purpose: 1. To determine the response of cantaloupe to soil
fumigation. 2. To observe promising breeding lines from other
February 25 Dow's Trizone was applied at 200 lbs./acre
to 2 of 4 replicates; chisel application was followed by
immediate dragging and covering with 4' wide clear 2-mil
March 16 Planting was made.
End nills- Smith's Perfect
Border rows 2 hills each of:
1. La. 30C-58
2. La. 15-22
3. La. 39
4. Md. 63-53
5. Va. 814
6. VBL63-37 12. Fla. 134-F7
7. VBL63-4 13. Seminole
8. VBL64-28 14. Fla. 8 x 4
9. VBL62-27 15. Hale's Best Jumbo
10. VBL-C496A 16. VBL 58-8
11. Fla. 67
10 culturall Practices Affecting Watermelon Maturity (Encap-
h~rbicide Test) (Crall)
purpose: To determine the effect of various cultural practices
cn early maturity.
Reults of previous years' trials: Polyethylene plastics,
whie sometimes promoting earlier melon maturity, have not
proved practical for use in watermelon culture. In 1963 and
previously, early maturity of watermelon was promoted by early
cate of planting, south sloping of beds, and application of a
12-inch-wide band of a petroleum-base mulch (Esso Engineering's
nzcap) over the planting row. In 1963 amiben incorporated into
the mulch resulted in good control of broad-leaved weeds without
any obvious phytotoxic effects on watermelon.
,964 Trial (Split-plot design)
Main treatments (planting dates)
1. No herbicide, no Encap
2. NPA (alanap) at 4#/A, no Encap
3. Same as #2, except sloped bed
4. Encap 2012, no herbicide
5. Encap 2374, amiben
6. Encap 2419, diphenamide
7. Encap 2362, dacthal
8. Encap 2420, trifluralin
1964 Results (Partial): Seedling emergence was earlier,
especially on the first 2 planting dates, in both mulched and
sloped beds than in flat unrulched beds. Weed control was not
particularly better after herbicide treatments, but experimental
error may have negated any beneficial herbicide effects.
:l. 'oil Fumigation (Schenck)
Purpose: To determine the effect of soil fungicides and fumigants
on soil fungi, nematndes, weeds affecting watermelon production
on old land.
Procedure: Materials applied on January 13 and 16; varieties
Charleston Gray and Florida Giant planted 20 days after treat-
Broadcast rate/acre Application method
2j Diiolatan 80W
3 ifolatan plus
5) Vapam plus
6) Difolatan plus
7) SD 345
9) EP 201
Results: 1963, Vapam and Vorlex looked most promising, however,
no Florida Giant plants survived until maturity. No significant
differences in yield of Charleston Gray watermelon among treat-
ment; Difolatan, Vapam and Vorlex had comparably good yields.
1964, Vorlex, EP-201, and Vorlex plus Difolatan look most
. ungicide Trial (Schenck)
Purpose: To compare the effectiveness of several fungicides in
the control of foliar diseases.
Procedure: 5 applications have been made at 3-11 day intervals;
plots consist of 10 hills of variety Charleston Gray.
1. Manzate D
2. Dithane M-22
3. Miller 658
4. Phaltan 50
5. Dithane M-22 + Dithane Z-78
6. Dithane Z-78
7. DAC 2787
8. Dithane M-45
9. Difolatan 80
10. DAC 2787
11. Difolatan 80
12. Dithane M-22 special
11. Difo7atan 80 (alternate applications)
Results: 1964, incomplete
Pounds per 100 gals.
3/4 + 1
1963, obtained good control of downy mildew with maneb plus
zineb, Difolatan 80, Manzate D, and Dithane M-45.
Recommendation: For gummy stem blight anthracnose and downy
mildew maneb 1 lb.) plus zineb (I lb.).
For bacterial leaf spot 50% copper(3 lb.) or maneb (1 lb.) plus
50% copper (3 lb.).
13. Fusarium Wilt Trial (Schenck)
Purpose: To compare commercial varieties for resistance to
Fusarium wilt In the field.
Procedure: 100 seed of each variety planted in each of 4
replicates. Number of wilted plants recorded at weekly
Dixie Queen, Wilt Resistant
14. -isecticide Trial (Adlerz)
trrpose: To evaluate various materials for control of rindworm
Date of planting: March 2
variety: Charleston Gray
Treatment: Eight applications at 7-10 day intervals beginning
at first blossom production.
SD 9129 3.2E
SD 7438 2E
SD 8447 50W
U 12927 75W
GS 13005 25W
Phosdrin 2E plus
Kepone 4% Bait at melons
Kepone 4% Bait broadcast
Results: 1964 data are incomplete. One experimental compound
D 8447 was phytotoxic (field plot Yellow 11).
Cn 1963, best results were obtained with Diazinon (1 lb.),
Dibrom (1 pt.) and Parathion (0.5 pt.). Excellent results
followed the use of Thiodan (1 lb.), Guthion (2 lb.) and
Phosdrin (1 pt.). In order to be most serviceable, a rindworm
insecticide should have as short as possible a period from
last application to harvest. For the above materials this
interval is as follows: Diazinmn, 3 days; Dibrom, 7 days;
Parathion, 3 days; Thiodan, 0 days; Guthion, 14 days;
Phosdrin, 1 day.
15. Leafminer Control (Adlerz)
Purpose: To determine the effectiveness of several materials
applied on different schedules for leafminer control.
Date of planting: December 27, 1963, at Immokalee, Florida.
Variety: Charleston Gray
Treatment: Applications were made between February 10 and March
Control was evaluated by samples taken between March 10 and
Results: Results are based on development of pupae in leaf
samples. Best results followed use of Cygon, Guthion and
Bidrin. Phosphamidon was less effective. The infestation of
leafminers was low, and under these conditions there was no
advantage to the greater frequency of application.
16. Compatibility Trial: (Adlerz, Schenck)
Purpose: To compare various pesticide-foliar fertilizer
spray mixtures for their effect on disease and insect control
and yield of watermelons.
Treatments: 48 combinations using one each of the fungicides,
insecticides, and fertilizers listed below; 5 applications at
7-10 day intervals; 10 hill plots of variety Charleston Gray.
Rates per 100 gals.
Diazinon 50 W
Results: 1964, incomplete
1962-1963, 3 combinations reduced disease control, 1 combination
reduced insect control, and 2 combinations reduced yield in
both seasons. No treatment had any visible phytotoxic effect.
No correlation was found between laboratory tests and field
results. In the 2 seasons 36 of 48 treatments had some adverse
effect on one or more factors.
Recommendations: Use only those materials in the spray tank
that are necessary for adequate insect or disease control.