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Group Title: Watermelon field day.
Title: Watermelon field day. 1973
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Permanent Link: http://ufdc.ufl.edu/UF00076045/00011
 Material Information
Title: Watermelon field day. 1973
Series Title: Watermelon field day.
Physical Description: Serial
Language: English
Publisher: Watermelon and Grape Investigations Laboratory, University of Florida
Publication Date: 1973
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Spatial Coverage: North America -- United States -- Florida
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Bibliographic ID: UF00076045
Volume ID: VID00011
Source Institution: University of Florida
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Resource Identifier: oclc - 144617905

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HISTORIC NOTE


The publications in this collection do
not reflect current scientific knowledge
or recommendations. These texts
represent the historic publishing
record of the Institute for Food and
Agricultural Sciences and should be
used only to trace the historic work of
the Institute and its staff. Current IFAS
research may be found on the
Electronic Data Information Source
(EDIS)

site maintained by the Florida
Cooperative Extension Service.






Copyright 2005, Board of Trustees, University
of Florida






*;7 (HUME LIBRARY-
1 WATERMELON FIELD DAY
('^ AGRICULTURAL RESEARCH CENTER, LEESBUR iUn 25
June 6, 1973 '2 3
1:30 PM
I.F.A.S. Univ. of Florida
Welcome to Watermelon Field Day and Introduction of Vis tors....-.
Jackson Haddox, Lake County Extension Director

Introduction of the Florida Watermelon Queen, Miss Cindy
Westmoreland

Welcome to the Research Center. J. M. Crall, Director,
Agricultural Research Center, Leesburg

Vegetable Crops Research in Florida. J. F. Kelly, Chairman,
Vegetable Crops Department, University of Florida, Gainesville

Grape Studies at the Agricultural Research Center, Leesburg.
J. M. Mortensen, Associate Geneticist

Breeding for Short-Internode Watermelon. H. C. Mohr, Chairman,.--,-----
Department of Horticulture, University of Kentucky, Lexington

Watermelon Rindworm Control.
Watermelon Mosaic Survey and Epidemiology.
W. C. Adlerz, Associate Entomologist

Fungicidal Control of Watermelon Diseases and Effect of Spray
Adjuvants.
Soil Fungicides on 'Old Land'.
D. L. Hopkins, Assistant Plant Pathologist

Watermelon and Cantaloupe Variety Trials.
Watermelon Rind Necrosis.
Chemical Weed Control in Watermelon.
Current Fertilizer Studies at Leesburg.
Cantaloupe Breeding.
G. W. Elmstrom, Assistant Horticulturist, Chairman of Watermelon
Field Day

Watermelon Breeding.
J. M. Crall, Plant Pathologist

Tour of Research Plots, Lawrence Sistrunk, Assistant Coynty
Agent, presiding





Leesburg ARC Research Report WG73-4
200 copies





-2-


1. Breeding Dwarf Watermelons (Mohr)

Three types of dwarf plants are being used: (1) "J" type, a
crown-rosette branched type (2) "T" type, a twisted-stem type
with vigorous growth, and (3) "D" type, essentially a "bush"
type. At the present time the "J" type plant appears to be
most adapted to commercial production.

Work at the Leesburg Center has been aimed at incorporating
resistance to anthracnose and Fusarium wilt into all three types.
Progress has been very good, and varietal releases appear to
be probable in a few years. There will be one or more releases
next year of dwarf types which are susceptible to disease.

2. Insecticide Trial Standards (Adlerz)

Purpose: To compare several recently evaluated, efficacious
materials with (standard) insecticides recommended many years
for rindworm control. Older standards are Guthiop,parathion,
Phosdrin, Thiodan.

Date of Planting: February 14

Variety: Smokylee

Treatments: Weekly applications (yellow stakes) beginning May 8,
before fruit set.

Treatments Rate/100 gal./acre

A. Guthion 2E 1.0 qt.
B. Parathion 4E 0.5 pt.
C. Phosdrin 2E 1.0 qt.
D. Thiodan 2E 1.0 qt.
E. Dipel 1.0 lb.
F. Dipel 0.5 lb.
G. Monitor 4S 2.0 qts.
H. Monitor 4S 1.0 qt.
I. Methomyl 90WD 1.0 lb.
J. Methomyl 90WD 0.5 lb.
Methomyl 90WD + Dipel 0.5 + 0.25 lb.
L. Methomyl 90WD + Biotrol XK 0.5 + 1.0 lb.
i. Methomyl 90WD + Thuricide 0.5 lb. + 1.0 qt.
N. Orthene 75 SP 1.3 lb.
0. Orthene 75 SP 0.6 lb.
P. Untreated

Results: This experiment has been conducted for 2 years. In
1972 there were no injurious populations of rindworms. Cabbage
looper, beet armyworm, and granulate cutworm larvae were found
in very limited numbers.

In 1973, no data were available at the time of printing this
program.








3. Insecticide Trial Bacillus thuringiensis (Adlerz)

Purpose: This test includes comparisons of various formulations
and rates of Bacillus sprays and the effects of various additives
on efficacy.

Date of Planting: February ill

Variety: Smokylee

Treatments: Weekly applications (white stakes) beginning May 10,
before fruit set.


Treatments


Rate/100 gal./acre


Biotrol XK
Bictrol XK
Biotrol XK
Biotrol XK + molasses
Bictrol XK + Nu Film Bt
Thuricide HPC
Thuricide HPC
Thuricide HPC + molasses
Thi'ricide HPC + Nu Film Bt
Thuricide HPC + Chevron Spreader
Diriel
Dipel
Dipel
Dipel + Nu Film Bt
Di-ol + Molasses
Untreated


3.0 lb.
2.0 lb.
1.0 lb.
1.0 lb.
1.0 lb.
2.0 qt.
1.0 qt.
1.0 qt.
1.0 qt.
1.0 qt.
1.0 lb.
0.5 lb.
0.25 lb.
0.25 lb.
0.25 lb.


nesultsc: See Insecticide Trial Standards.



4. Watermelon Mosaic (Adlerz)

Purpose: To observe the development of mosaic disease in the
field and correlate its initiation and increase with aphid flights.

Date of planting: These observations are made on plots designed
for other experimental purposes so dates of planting are not
uniform.

Results: Initial spread of WMV-2 into experimental plots is not
co.:elated 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.

Whenever winged aphid populations are large, mosaic development
is extensive, 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.


+ 2 gal.
+ 1 pt.


gal.
pt.
.5 pt.


+ 1 pt.
+ 2 gal.








At Leesburg, the spirea aphid develops on a very wide variety
of weed, ornamental, and crop plants, and often comprises most
of the winged aphid population at the time of peak aphid occurrence.

In 1973, first symptoms of mosaic appeared prior to peak aphid
flights. Mosaic development was rapid after April 28 and the
effect on some plots was severe. Initial infection occurred in
the southeast corner of the field (root type experiment) and
later infection was most extensive along the south side (root
type and variety trials).

Table 1. Aphids/trap/week on sticky board traps at 4 locations
near experimental plots in April and May, 1973.

Week ending
April May
3 10 17 24 1 8 15 22

N 210 28 159 407 76 46 14 8
S 160 59 287 567 402 80 23 11
E 69 71 210 539 95 57 12 9
W 180 46 158 353 150 55 30 4

Average 155 51 203 467 180 59 20 8



Table 2. Percent mosaic in experimental plots in April and May,
1973.

Week ending
April May
12 19 28 6 13 18 26

Root type 0.6 3.1 7.6 75.9 94.7 100.0 -
Variety Trial 0.0 0.0 0.0 3.1 27.7 79.9 93.7
Rind necrosis 0.0 0.3 0.3 3.5 27.5 51.3 -
Fungicide 0.0 0.0 0.0 1.3 15.3 35.3 68.81
Spray adjuvant 0.0 0.0 0.0 1.7 11.5 22.0 -
Insecticide 0.0 0.0 0.0 0.2 8.8 28.5 40.61


1 Partial count.



5. Fungicide Trial (Hopkins)

Purpose: To compare fungicides for control of fungus foliar
diseases of watermelon.

Date of Planting: February 23, 1973.


Variety: Charleston Gray








Procedure: Treatments (white stakes) were applied weekly
beginning May 11. They were applied in 100 gal. of water at
150 psi using a boom-sprayer with a 14-foot boom.

Treatments Rate per 100 gal. per acre

A. Benlate + Manzate 200 0.5 lb. + 1.5 lb.
B. Dithane M-45 1.5 lb.
C. Difolatan 4F 2.5 pt.
D. Bravo W75 2.0 lb.
E. DPX 740 + Manzate 200 4 oz. + 1.0 lb.
F. RH-3928 + Dithane M-45 0.5 lb. + 1.5 lb.
G. Bravo 6F 2.0 pt.
H. Untreated
I. DPX 740 4 oz.
J. RH-3928 + Dithane M-45 0.25 lb. + 1.5 lb.

Results: 1972. Downy mildew and gummy stem blight were both
present and about equal in severity. Benlate + Manzate 200,
Bravo i'75, Difolatan 4F, and Dithane M-45 provided very good
disease control. Two copper fungicides, Micro-Flo Copper and
Tribasic Copper Sulfate, were not quite as effective in controlling
these two diseases as were the organic fungicides mentioned above.

1973. Eecults were not available for program. We will observe
these plots on field tour.

Recommendations: Dithane M-45 80% (1 1/2 Ibs.); Manzate 200 80%
(1 1/2 l'bs.); ianeb 80% (1. 1/2 Ibs.); Difolatan 4 flowable
(2 1/2 pt3.); Bravo 75% (1 1/2 to 2 1/2 lbs.); *Benlate 50%
(1/4 to 1/2).

*Does not control downy mildew or Alternaria leaf spot.



6. Fun -Spray Adjuvant Test (Hopkins)

Purpose: To c..mpare the effect of spray adjuvants on the control
of watermelon foliar diseases with fungicides.

Date c_ ?Ianting: February 23, 1973.

Variety: Smokylee

Procedures: Treatments (green stakes) were applied at a pressure
of 150 psi using a boom-sprayer with a 14 foot boom. First
treatment was applied on May 16.





-6-


Spray
Interval
Treatment (Days)


Rate per 100
gal. per acre


Dithane M-45
Dithane M-45
Dithane M-145
Dithane M--45
Dithane M-45
Dithane M-45
Difolatan 4F
Difolatan 4F
Difolatan 4F
Difolatan 4F
Difolatan 4F
Difolatan AF
Difolatan 4F
Difolatan 4F
Dithane M-45
Dithane M-45
Nu-Film 17
Unsprayed


+ Nu-Film 17
+ Bio Film
+ Triton B-1956
+ Ortho X-77
+ Ortho Tronic

+ Nu-Film 17
+ Bio-Film
+ Triton B-1956
+ Ortho X-77
+ Ortho Tronic

+ Nu-Film 17

+ Nu-Film 17


1.5
1.5
1.5
1.5
1.5
1.5
2.5
2.5
2.5
2.5
2.5
2.5
2.5
2.5
1.5
1.5
1.0


lb.
lb.
lb.
lb.
lb.
lb.
pt.
pt.
pt.
pt.
pt.
pt.
pt.
pt.
lb.
lb.
pt.


+ 1.0 pt.
+ 6 oz.
+ 6 oz.
+ 6 oz.
+ 1.0 pt.

+ 1.0 pt.
+ 6 oz.
+ 6 oz.
+ 6 oz.
+ 1.0 pt.

+ 1.0 pt.

+ 1.0 pt.


Results: 1972. Differences among fungicide-spray adjuvant treat-
ments were relatively small in the test, perhaps due to a dry May
and June. Nu-Film and Bic-Film did appear to enhance the disease
control provided by Dithane M-45.

1973. Results were not available for the program. Plots will
be observed on field tour.



7. Soil Fungicide Test (Hopkins and Elmstrom)

Purpose: To determine the effect of soil fungicides and fumigants
on damping-off and Fusarium wilt of watermelon on "old" land.

Date of Planting: March 1, 1973.

Varieties: New Hampshire Midget (wilt susceptible), Charleston
Gray (moderately resistant), Smokylee (highly resistant).

Procedure: Vorlex fumigant was applied on February 8 to 30-inch
flattened beds by injection. After injection of Vorlex the
surface of beds were sealed with foam, or water. Some of the
Benlate treatments were applied to the bed and incorporated with
a rotovator on February 28. These plots were watered after
rotovating to prevent blowing of the loose soil. Other fungicide
treatments were applied as concentrated sprays directly over the
young seedlings.






-7-


Treatment


Benlate
Difolatan
Manzate 200
Demosan
Benlate + Demosan
Benlate
Benlate
Mertect
Benlate
Benlate + Benlate


11. Vorlex
12. Untreated


Broadcast
rate/acre


lb.
pt.
pt.
lb.
lb. + 2 lb.
lb.
lb.
lb.
lb.
lb. + 2 lb.

gal.


Application Method

3 weekly sprays
3 weekly sprays
3 weekly sprays
3 weekly sprays
3 weekly sprays
1 spray at emergence
weekly spray
weekly spray
incorporated
incorporated +
3 weekly sprays
Injection


Results: 1972. Weekly concentrated sprays of Benlate provided
good control of damping-off in Charleston Gray and New Hampshire
Midget. Smokylee wasn't included in the 1972 test. Demosan
and Vorlex also provided control of damping-off.

Vorlex, Benlate incorporated, Benlate spray, and Mertect incor-
porated provided some control of Fusarium wilt in Charleston
Gray. Only Vorlex provided any control of wilt in New Hampshire
Midget.

1973. In Charleston Gray, Benlate incorporated + 3 Benlate sprays,
Benlate + Demosan (3 sprays), and Vorlex provided the best control
of damping off. Other treatments provided some control. In New
Hampshire Midget, only Vorlex controlled damping-off and seedling
wilt. In Smokylee, damping-off was not very serious even in
untreated, making comparisons between materials difficult.

Data on Fusarium wilt were not available for program.



8. 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 February 22. Allsweet was planted February 27.

Entries:


'Breeder's' Jubilee
'Commercial' Jubilee
Crimson Sweet
Smokylee
Sweet Princess
Petite Sweet
Allsweet
Summerfield


9.
10.
11.
12.
13.
14.
15.
16.


'New Strain' Jubilee
Klondike Blue Ribbon
Charleston Sweet
Louisiana Queen
W-890
W-111
Top Yield
Charleston Gray


1.
2.
3.
4.
5.
6.
7.
8.
9.
10.





-8-


Results: 1972. See Mimeo Report WG73-3, Watermelon Cultivars
for Florida.

1973: Petite Sweet very early maturing but quite wilt susceptible.
Top Yield, Klondike Blue Ribbon and 'Commercial' Jubilee also
quite wilt susceptible as of May 25 total wilt in Jubilee was as
follows:


'Breeder's' Jubilee
'New Strain' Jubilee
'Commercial' Jubilee


- 1 out of 80 plants
-2 out of 80 plants
- 25 out of 80 plants


9. Cantaloupe Variety Trial (Elmstrom)

Purpose: To compare promising breeding lines and new varieties
with standard commercial varieties.


Procedure: Single-row plots in
replications were planted March

Entries: Replicated Trial.


Planters Jumbo
VBL 67-1-M5
VBL C880-M3
VBL 63-4-MI
AC 67-17
AC 67-59
AC 68-51
AC 68-55
AC 68-57


randomized blocks with 4
13.


10.
11.
12.
13.
14.
15.
16.
17.
18.


Edisto 47
Fla. 6-28L
Southland
Gulfcoast
Samson Hybrid
Gulfstream
Fla. 45
Fla. 1,35
Eden Gem


Observational Trial:


L72-10
AC 66-12
VBL 67-1-M4
VBL C926


Fla G-129
Tam Dew
Saticoy Hybrid
Burpee Hybrid


Results: See Mimeo Report WG73-2, Cantaloupe Cultivars for
Florida.



10. Herbicide Trials (Elmstrom)

Purpose: To evaluate various materials for pre-emergence control
of weeds in watermelon plots.

A. Replicated Herbicide Trial.

Procedure: Allsweet watermelon seed was sown March 9. The
following treatments were applied at planting:








Number Treatment


lb. a.i./acre


Incor-
poration


Devrinol
Devrinol
Devrinol
A820
A820
Bensulide
Chloramben
Nitra.lin
Naptalam
Napta lam
Naptalam + Devrinol
Naptalam + Devrinol
Naptalam + Devrinol
Trifluralin
Alachlcor
Diphenamid
Hoed check
Unhoed check


2.5
5.0
10.0
1.5
3.0
5.0
2.5
1.0
3.0
3.0
3 + 5
3+5
3+5
1.5
2.0
6.0


+
+
+
+
+
+
-


+
+,+

-,+
+


Results, 1972: Weed control with naptalam plus devrinol, A820,
and devrinol alone tended to be better than with NIA 20439 or
naptalam applied alone. Yield from the naptalam plus devrinol
treatment was equal to that of the hoed check.

1973: Diphenamid, chloramben, and devrinol (10 Ib/acre) were
somewhat phytotoxic as was the naptalam plus devrinol combination
when both materials were surface applied. The most vigorous
plants were in the check plots and in the plots treated with
bensulide, nitralin, alachlor, or A820 (1.5 Ib/acre). Weed
control and yield information is incomplete.

B. Activated Charcoal/Herbicide Trial.


Procedure: Smokylee watermelon seed was
which includes the following treatments.


sown March 7 in a trial


Treatment

Diphenamid
Diphenamid
Diphenamid
Diphenamid
Diphenami d
Diphenamid
Diphenamid
Diphenamid
Triflural in
Trifluralin
Trif luralin
Trifluralin
Trifluralin


lb a.i./acre


4
4
4
6
6
6
6
0.75
0.75
0.75
0.75
1.50


Protectanta


None
Plug mix
Charcoal
Plug mix
None
Plug mix
Charcoal
Plug mix
None
Plug mix
Charcoal
Plug mix
None


+ charcoal



+ charcoal



+ charcoal


Number





-10-


Number Treatment


lb a.i,/acre


Protectanta


Trifluralin
Trifluralin
Trifluralin
Hoed check
Unhoed check


1.50
1.50
1.50


Plug mix
Charcoal
Plug mix + charcoal


a Plug mix = shredded sphagnum peat moss + vermiculite.
Charcoal = 300 Ib activated charcoal applied in 6-inch square.

Results, 1972: Terbacil surface applied at rates of 0.75, 1.5,
and 3.0 lb. a.l./acre adequately controlled weeds but was somewhat
phytotoxic to direct-seeded watermelon. When terbacil was applied
at the lowest rate, activated charcoal applied on the soil surface
or incorporated at rates of 300 or 900 lb./acre in the planting
hill reduced herbicide injury. Method of charcoal application
was less important than rate in reducing phytotoxicity of the
herbicide.

1973: Both rates of diphenamid were phytotoxic but no trifluralin
injury occurred. Charcoal alone was most effective in reducing
diphenamid injury. Weed control and yield information is
incomplete.



11. Slow-Release Fertilizer Trial (Elmstrom)

Purpose: To determine the effect of slow-release fertilizer
(sulfur-coated urea and sulfur-coated KCI) on yield, shape, and
soluble solids content of 'Smokylee' watermelons.

Procedure: Two-row plots with 4 replications were planted March 1.
The following fertilizer treatments were applied.


Treatment
number


Number of
aoplications


Total pounds
N and KO
per acre


1-
2
1
2
Biweekly
1


120
120
360
360
360
40
80
120
240
120


commercial
fertilizer




Sulfur-coated
urea + KC1


a N and K derived from sludge, ammonium nitrate, sulfate of
ammonia, and potassium nitrate.
b 80 lbs N and K20 from sulfur-coated material (at planting)
and 40 Ib N + K20 from nitrate of soda-potash (layby).


1
2
3
4
5
6
7
8
9
10





-11-


Results, 1972: Release of N and K20 from Osmocote (14-14-14) was
too slow to meet crop requirements. Yield and soluble solids
content were higher when sulfur-coated materials were used than
when equivalent rates of commercial fertilizer were applied.

1973: Early vigor was highest when S-coated fertilizer was
applied (except for the 240 lb. rate) and when split applications
of the lowest rate were made. Melon yield and shape information
is incomplete.



12. Rind Necrosis Trial (Elmstrom and Hopkins)

Purpose: To study the effect of variety and nutrition on develop-
ment of rind necrosis in watermelon.

Procedure: Two-row plots with 4 replications were planted
February 22. Three varieties were planted Sweet Princess,
Charleston Gray, and Summerfield. Supplemental applications
of boron, calcium, and magnesium were made during the season.
At harvest the melons will be cut and the incidence of rind
necrosis will be noted.

Results, 1972: Significant differences on the incidence of
rind necrosis in several watermelon varieties were noted.

Entry Rind necrosis (%)

Sweet Princess 10.0
Jubilee 14. 4
Top Yield 17.2
Allsweet 17.8
Crimson Sweet 22.6
Charleston Gray 27.9
Smokylee 30.0
Charleston Sweet 36.1
Louisiana Queen 36.7
Klondike Blue Ribbon 39.1
Summerfield 44.6

1973: Info.mation is incomplete.



13. Cantaloupe Breeding (Elmstrom)

A limited program to develop parental lines with genetic
properties suitable for Fl hybrid seed development is continuing.
An Fl hybrid line was entered in the 1973 Southern Cooperative
Cantaloupe Variety Trial. Twc Florida lines which have excellent
combining ability with a number of commercial varieties have
been selected. Incorporation of the gynoecious or monoecious
flowering habit into these two lines will facilitate hybrid seed
production. Incorporation of the moncecious characteristic is
proceeding but several problems have developed in working with
the gynoecious character.





-12-


14. Watermelon Breeding Plots (Crall)

In 1961 a program was initiated 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 (Race 1)
resistance in a high quality shipping-type watermelon. Smokylee,
which was released in 1971, was developed from this program. It
was selected from a Texas W5 x Charleston Gray cross. Other lines
in advanced generations from similar crosses are being evaluated
for potential release. Most promising are a Watson-type line and
round melons, with various rind colors and patterns, that are very
similar to Smokylee in wilt resistance, anthracnose resistance,
and fruit qualities. More recently, an intense red flesh color
from certain Peacock lines was incorporated into a number of lines
of various fruit types.

In 1969 we began a series of crosses between our better large-
fruited lines and various small-fruited varieties, including
New Hampshire Midget, Sugar Baby and various small-fruited lines
from several foreign countries, especially Japan. The aim of
this part of the breeding program is to develop small-fruited
varieties with combined resistance to fusarium wilt and
anthracnose, deep red flesh color, and other desirable fruit
qualities. We are seeking to develop varieties that might be
adapted to shipping in cartons, mostly round shapes, in a range
of sizes from 1 to 20 pounds. This season these lines are mostly
in the F3 or F4 generation and are still several years away from
possible release.

Both greenhouse and field tests conducted in 1971-72 confirmed
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. Seed from some commercial seed stocks
were almost completely susceptible. Increases of seed from
"breeder" stocks (made by us in the late summer of 1971) were
made available to commercial seedsmen for 1972 plantings, so that
"registered" (one generation removed from "foundation") seed of
Jubilee was available in good supply from various commercial
seed sources for the current season. Our tests show that plantings
from such seed are much more wilt resistant than plantings from
previously available commercial seed stocks.




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