Historic note

Group Title: Watermelon field day.
Title: Watermelon field day. 1984.
Full Citation
Permanent Link: http://ufdc.ufl.edu/UF00076045/00016
 Material Information
Title: Watermelon field day. 1984.
Series Title: Watermelon field day.
Physical Description: Serial
Language: English
Publisher: Watermelon and Grape Investigations Laboratory, University of Florida
Publication Date: 1984
Spatial Coverage: North America -- United States -- Florida
 Record Information
Bibliographic ID: UF00076045
Volume ID: VID00016
Source Institution: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: oclc - 144617905

Table of Contents
    Historic note
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Full Text


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

site maintained by the Florida
Cooperative Extension Service.

Copyright 2005, Board of Trustees, University
of Florida


UN FVERi ;I'Y OI' l,'[,nRlEfDA, TFAS
Gary Elrnstromn, Center Director
June (), 198y 1:30 PM

'l (lly, Laki *ouniy l 'l'ti;r 1 )' ) l >1 rector Moderator

Welcoming comments Gary Elmstrom, Director, Agricultural
Research & Educat Ion Centor, I.eesburg

D):;cussions of (:rrient Research

James Crall, Plant Pathologist, Leesburg
Watermelon breeding
Breeding lines submitted for release
Improved wilt resistance in Jubilee & Charleston Gray

Gary Elmstrom, HIorticulturist, Leesburg
Cucurbit variety evaluation
Muskmelon breeding
Squash breeding

Don Hopkin: Plant Pathologi.st, Leesburg
Watermelon disease control
Muskmelon disease control
Squash disease control
Watermelon 'old land' :;tudie's

Warren Adlerz, Entomologist, Leesburg


JUN v 24 i985

L.F.A.S.- Uiv. of Florida
----------1.. _

Pickleworm control on squash
Cucurbit virus studies

Mark Sherman, Assistant Horticulturist, Gainesville
Handling and marketing deve lopments

lerfreshments (Coun tesy of( For'emrost b'lrtilizer Company)

Tour oP research plots, 13i 11 Stall, Associate Horticulturist,
Gainesville, Presiding

leesburg AREC Research Heport (LBG 8 1-.1)
200 Copies

Thep Institute oI'FF{' .d. ft ti nces rmploymrnent Opportunity Affirmative Action Employer authorized to provide research,
educational inforP- :s on0 o I wuviduals an,' 'titutuons that function without regard to race, color, sex, or national origin.

1. Watermelon Bre d I rn ( C1 'a )

T'Ie watermielon bIni )I'd(l I ng pltogIra at AREC Loesburg was
initiated in 1930 with the planting of 104 varieties on
10 leased acrne. Selections were made for resistance
to Fusarium wilt, which was the major problem of Florida
growers at thai t, Ime. It I still an important consid-
eration for growers, but wilt resistant cultivars have
considerably lessened the impact of Fusarium wilt on
watermelon production in Florida. Important goals of
the watermelon breeding program over the years have been
the development of' varieties with multiple disease re-
sistances in v gforous and prolific vines producing
melons with desirable eating and shipping qualities.
At the present time most of our breeding lines have high
level resistance to Fusarium wilt and race 1 anthracnose.
Our current program includes work on resistance to gummy
stem blight and mosaic, but lines with resistances to
these diseases are early generation progenies.

Seven varieties have been released from this program
since its inception: Leesburg (1936), Blacklee (1944),
Ironsides (1952), Jubilee (1963), Smokylee (1971),
Dixielee (1979), and Sugarlee (1981). Two small-fruited
("icebox") types (FLA 81-3 and F82NC) and one Charleston
Gray type (F83CE) have been recommended for release and
are currently under consideration for release as new
varieties. in addition to the three lines under current
consideratlon tfor release, one additional Charleston
Gray type (F8IjNE) and two Jubilee types (82M5-2 and
82120-I;) are In the fina] stages of evaluation, and re-
commendation for release as cultivars is anticipated
within the year. We have other promising lines of the
Dixielee and "icebox" types but none are near release

Emphasis in breeding better horticultural types with
anthracnose Presi:stance and high level resistance to
Fusarium wilt is currently being placed on lines with
four distinct melon types: Charleston Gray types and
Jubilee types (mostly by backcrossing), large round
striped melons. (similar to Dlxicelo and Sugarlee), and
small-fruited Lines mostlyy with light green rind color).
In addition, we have a program, in an earlier stage, to
develop short' !nternode (dwarf) 1.1nes with resistance
to anthracnose and Fusarium wilt and fruits similar to
those in our main breedingi program.

The breeding I' leld and evaluation test portions of this
yeart': field plots include Ranges L through Z and AA
through FF. Ranges L O encompass a replicated trial
that includes F83CE (Charleston Gray type recommended for
release) and F82NW (82PM5-2) (Jubilee type near release
status). Ranes: P W encompass a replicated trial of



advanced selections that Include12 all lines currently
recommended for release or antilclpatod for release status
within a year. Ranges 1313 l'I'" encompass this year's
breeding field area, which also includes all these same

Dwarf liners (pri ':(nrl es :;,''er,:iat i\ ) may be found in Rows
DD3-7 and EE1-8. Mosaic resistant lines are in Rows
BB3-8, CC3-8, and DD8. Gummy stem blight lines are in
Rows FF1-8.

Lines currently being considered for release may also
be found in Variety Trials being conducted by Dr. Elmstrom.
The watermelon Fungicide Trial (Dr. Hopkins) is planted
with the Charleston Gray type F83CE.

;. Wat e1-melon Var!i ety Trial (Elmn:;trom, Crall)

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

Procedure: Two-row plots were planted February 22 in
randomized blocks with 3 replications.

Entries, Replicated:
1. Dixielee
2. Sugarlee
3. Charleston Gray
l1. Jubilee
.Crimson :;w(e t
6. Sunshade
7. AU-Producer
8. AU-Jub I plant
9. Prince Charles
10. Long C'ri mason
11. Smokylee
12. Oasis
13. Charleston Cray !//
1l. FLA 78SE1
15. FLA 78SE I

2 3.
2 8.

FLA 81-3
NKX 4253
AU //11
NVIIH 1254
no entry
rno entry
Xl'ir 957
Royal Charleston
Ioyal Peacock
Royal Jubilee
Royal Sweet
southern n Belle
Rebel Queen
Petite Sweet


Entries, Observational:
1. F82NW
2. F82NE
3. F82CE
4. F82NC
5. Sugar Baby
6. L390-2
7. L392-1
8. Mirage
9. XPH 962
10. XPH 5024
11. XPH 5082
12. NVH 4257
13. NVH 4258
14. NVH 4261
15. NVH 4300
16. NVH 4301
17. 83W30


FMX 11
PSR 24083
PSR 24183
PSR 25883
PSR 27183
Tri X 313
Triple Sweet
AU #20
AU #21
AU #22

Results: 1981. The most productive entries were Calhoun
Gray, Charleston Gray #5, Charleston Gray, Jubilee, and
Dixielee. Average soluble solids content of the flesh
exceeded 10% in Sugarlee, Dixielee, Oasis, and FMX 4.

1982. The earliest maturing entries were FLA 78SW2,
FLA 79SE, FLA 78SW4, and Madera. Total marketable yield
was highest fol Prince Charles, Charleston Gray #5, Cal
Sweet, and I'LA 78SW4. Soluble solids content was highest
in Smokylee, Oasis, Sugarlee, AU-Jubilant, FLA 78SW2,
and Crimson Sweet.

1983. The most productive entries were Royal Jubilee,
NKX 4253, Sugarlee, Calhoun Gray, and Prince Charles.
Earliest maturing varieties were FLA 78SW4, Royal
Charleston, and Prince Charles. Varieties with the
highest soluble solids content were Dixielee, Sugarlee,
Oasis, Royal Jubilee, and Royal Peacock.

1984. Incomplete. The first cutting of the trial was
May 29. Entries are labeled in the field and, where fruit
have matured, will be available for taste sampling.
Early maturing entries were Sugar Baby, Petite Sweet,
Crimson Sweet, Southern Belle, Royal Charleston, NVH 4257,
XPH 5082, PSR 24183, FLA 81-3, and XPH 957.

3. Cantaloupe Variety Trial (Elmstlrom)

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

Procedure: Twenty varieties and breeding lines were
planted February 241 in repllicaited, ;ingle-row plots.
Thirty-two lines were planted in s Lngle-row, observational

Entries, Repllcated:
1. Hiline
2. Venus
3. Limelight
4. Top Not
5. Castle Rock
6. Harvest Pride
7. Honeygrow
8. Magnum .45
9. Samson
10. Camelot

Entries, Observational:
1. Ambrosia
2. no entry
3. GSV 83-93
4. Edisto 47
5. PMR 6
6. PMR 45
7. Mainstream
8. FL 93-8
9. FL 93-71
10. 81-3085
11. HXP 3590
12. HXP 3587
13. HXP 3588
14. ARCO 101
15. XP 673
16. BUX #5-74

1. I


4Market Pride
Gold Star
Green Ice
Burpee Hybrid

PSR 383
PSR 483
PSR 583
PSR 1383
PSR 6683
PSR 7083
PSR 7683
PSR 7783
PSR 7983
PSR 9281
NVH 876
NVH 881
HXP 3589

Results: 1981. Hglheot total marketable yields were
obtained from Planters Jumbo, Mainstream, Luscious,
Chieftain, Summet, Classic, Star Trek, and Ambrosia.
Earliest entries were Luscious, Sweet-N-Early, Juno,
and Classic. Soluble solids content exceeded 12% in
Saticoy, Venues, and Chieftain.

1982. The highest yielding varieties were Juno, Gold
Star, and Planters Jumbo. Earliest maturing were Burpee
Hybrid, Superstar, and Juno. Downy mildew resistance
was best in AC 75-1C, Edisto 47, Juno, Planters Jumbo,
and AC 68-52; varieties most resistant to powdery
mildew were Juno, Summet, Chieftain, Mainstream, AC 75-
IA, and Magnum .45. Soluble solJds were highest in Juno,
Earlidew, and Chieftai n.

'- 5-

1983. The hilghlest yielding entries were Supermarket,
Musser 81-3085, Burpee Hybrid, and Gold Star. The
earliest onts were Ai.ava, Cold Star, and Burpee Hybrid.
Soluble solids content exceeded L2% in Earlidew, Juno,
Gal la, and Ail) r,; !"ia.

19884. Incomplete. The earliest maturing entry was
XP 673 which bean ripening May 25. However, this entry
Is also the most susceptible to downy mildew. Differences
in plant re:-, Istance to downy and powdery mildew will be
evident during the field tour.

'I. Sinall-SLe Watntrimlleon Vari ety and Spacing Trials (Elmstrom)

Over the last few years trials have been conducted on
watermelon varieties which produce "icebox" (small size)
watermelons and have vines that are not as prolific as
are the vinos of standard commercial varieties. Some
of these varieties have a short internode (bush type)
habit of growth.

In 1982 a pii't iol of t1,he trial was lost due to high water
but the following resulL; weri' obtained:

111 i Yie ld Melon
Var I ty space i. r (cwl/A) weight
(Inches) (lb./fruit)

i'LA 81-3 2 '37 8.3
FLA 81-3 16 113 6.9
Yellow Baby 21 311 3. 8
FA 81-2 24 328 4.7
FLA 81-3 32 306 8.2
Sweet Baby 24 282 8.1

In all treatmiints row;s were spaced 5 feet apart. At
a h 1 spacingl of 2'\ inches, 11' ,A 81-3 was more productive
than Yellow Baby, FLA 8-2, arid Sweet Baby. The marketable
yield of FLA 81-3 was higher at the 24 and 16 inch spacings
and fru.t si::e was smallest at the 1.6 inch spacing.

hi a similar trial in 1.983, the following results were
()obI aI ned.


111I 1, Y ((1ld Melon
Variety spacing (cwt/A) weight
(inches) (lb./fruit)

FLA 82NC 24 553 5.8
ILA 82NC 16 520 5.0
FLA 81-3 24 519 6.7
FLA 81-3 16 502 6.3
FLA 82NC 32 502 6.4
Sweet Baby 24 490 7.8
FLA 81-3 32 462 7.0
Yellow Baby 24 369 5.2
Sugar Baby 24 247 7.4
Potite Sweet 24 186 5.5
Garden Baby 24 90 4.2

Once again fruit size increased as hill spacing increased
from 16 to 32 Inches. At the 24-inch spacing the Florida
breeding line:; were more productive than available
commercial "icebox" varieties.

Tills year the following lines are being compared at a
hill spacing of 24 inches:

1. Bush Jubilee 5. Sugar Baby
2. Bush Charleston Gray 6. FLA 81-3
3. Yellow laby 7. F'83NC
4. Baby 'un 8. F83NW(E)

5. Cucurbit Variety Evaluation (Elmstrom)

Tn addition to the watermelon and cantaloupe variety
evaluations, trials o.f squash and cucumber varieties
have been conducted since 1977. Results of these trials
are included in the following publications which are
available upon request:

I. Cucurbit Variety Evaluation, 1977-1980.
Leesbur 1g ARC iResearich Re)por't (WO 80-9).

2. Cucurbit Variety Evaluation, Spring 1981.
Leesb, ur ARC Hsocarich Report (WG 81-3).

3. Cucurb.it Var lety Evaluation Spring, 1982.
Leesburg ARC Research Report (LBG 82-2).

1. Cucurh it Variety Evaluation, 1983.
Leesblur1' ARC H(:esearch Report (LBG 83-4).


VegetabJu Vartiety 'Tral kIu tults in Florida for
1978--1970-198 Circular ,-289.

6. Vegetable Variety Trial Results in Florida for
1981 ('1 tcular :-301.

7. Vogteltb) l Vari ety Trial Hc1:;ul t; in Florida for
1982. CI rcular ;'-306.

,. C(ant aloupe H l'o(II-ngl (l:;1m;t rom)

Purpose: To evaluate the combining ability of some
var Leties and breeding I linr; and to develop parental
lines with genetic properti.Les suitablee for F1 hybrid
seed production.

Procedure: Almost without exception, the highest quality
muskmelon fruits are produced by hybrid varieties.
However there is a reluctance on the part of growers to
plant hybrid seed since the cost is 10 to 15 times greater
than that of open-pollinated varieties. The high price
or seed Is the result of the need for hand emasculation
and hand pollination to produce hybrid seed. At present,
I am attempt iig to incorporate various characters into
parental lines which would make them more suitable for
parental lines and reduce the cost of hybrid seed. A
new male-ste.rile gene was released to seed companies
during 1983 by the ARE(' Loeeolurg. Studies are continuing
on the usefulness of either the monoecious or gynoecious
flowering habi:t for production of hybrid muskmelon seed.

7. Squash BreedIn g (E lmstrom)

This is a relatively new program at the AREC Leesburg.
The primary goals are the incorporation of mildew and virus
ire:; Istance into commercially acceptable varieties of yellow
and zucchini summer squash. Attempts are being made to
transfer resistance from two wild squash species, Cucurbita
martinezii and C. ecuadorensis, into C. pepo.

Thlu spring we have identified lines with resistance
(tolerance) to powdery mildew and Watermelon Mosaic Virus II.

8. Watermelon lung I cides (I{opkins)

Date of Plantinlg: March 1, 19811


Variety: Charleston Gray Backcross F83CE

Procedure: Spray application dates were April 26, May 3,
10, 17, 24, and 31. Sprays were applied at a pressure of
150 psi and In 100 gallons of dilute spray per acre, using
a boom sprayer.

Difolatan 80 Sprills
Difolatan 80 + XE779L
Dithane M-14 + Triton 1-1956
Rovral 50
Rovral 50
Rovral 50
Topsin M

Rate (amt./100 gal./acre)


lbs. + 0.1 lb.
lbs. + 2 oz.

Results: Results are not available yet. Plots may be
observed on the field tour. Many of the fungicides listed
above are not yet cleared for use on watermelon.

Fungicides I'oi Watermel on:

Relative effectiveness
Materials and rate (amt./acre) GSB DM
Manzate D 80%, 2-3 lbs + ++
Dlthane M-22 Special 80%, 2-3 lbs. + ++
Manzate 200 80%, 2-3 lbs. ++ +++
Dithane M-45 80%, 2-3 Ibs. ++ +++
Difolatan 80 Sprills, 1 1/2-3 lbs. +++ +
Bravo 500, 2-41 pts. +++ +++
Benlate 50, 1,/'-1/2 11. +++ 0
Ridomil MZ-58, 1 1/2-2 Ibs. 0 +++

+++ = highly effective; ++ = moderately effective; + =
effective; 0 = not, (eff'lectiVe. I3B = gummy stem blight;
DM = downy mildew.

9. Cantaloupe ]'ungrlcides (Hlopk in:;)

Variety : SupI f ir.arIkt

Date of Prlant ilu: March 13, 1)8'l

Procedure: 'Treat-ments5 we te a)ppIleod April 25, May 2, 9, 16,
3, 25, and 30". Spray were applied at a pressure of 150

r-1 n-

psi and in 10) lal .loin; ol' di uti spr ay per acre, using a
boom sprayer.

DMiaac raLrPM
T'lC)aitrreniLt nain r';t, (;urin /*tcnm) DM PM

Bravo + Vi niuei. ( 2.)5 tn. + 1.0 1 b. )
H[avo alt. withl VUilcii M
(2.5 pts. & 2 qts.)
Bravo (2) then DS-6 n3l
(2 pts. + 2 Ibs. )
Bravo (2 pts. 12] thUel 3 pts.)
D.Ithane M-11' (2 lbs..) + Karathane +-
Dithane M-45 D;, (2 lbs.) + Karathane
+ B-1956
Bravo (2) then Ridomil MZ-58
(2 pts. + 1.8 lbs.)
Mandate 200 + DPX 116573
(2.0 Ibs. + 1 oz.)
Difolatan 80 pillss (1 .5 lbs.)
1)1 'olatan 80 4 XE779LH
(1.5 lbs. 4 ). 1 Ib.)
KWG-0519 + Ridiomil MZ-'8
(; o,. 4 2. 0) L)8.)
Bayleton + Ridornil MZ-5'
(1 ( + 2 () lII )
X1,779L, (0.1 lb. )
XBI7/9L (0. 05 lb.)

1.0 a
1.1 a

1.2 a

1.6 a
2.1 ab

2.2 abc

2.7 abcd

3.6 bcde

3.9 cde
3.9 cde

3.9 cde



1Barratt-Hor;rall ratl.iigs system: 0 = no disease,
disease, 11 = 100% disease, DM = downy mildew and
powdery mildew. Rat -in ,gs were c made on May 23.

'Funigicides f'or Use on (Cantaloupe:

Ma:lt.erl ; I:; n11 r'ate( (:amb ./lac.e' )
Mandate 200 80%, 2-3 lbs.
Dithane M-45 80%, 2-3 lbs.
'Bravo 500, 201 pts.
DI folatan 80 1,ri s, 1 1/2-3 lbs
Karathane 25-, 6-12 o::.
Benlate 50W, 1/8-1/2 1b.
Ridomil MZ-5TR, 1 1/2-2 lbs.
Bayleton, 2-11 wz.

0.5 abc
0.8 c

0.6 bc


0.9 c


0. 4 abc

0 a

0.1 ab

de 0.3 abc


6 = 50%
PM =

Effective on:1

PM Alt.

p .,\,

++ ++ +
++ ++ +
++ + ++ ++
+ ++3 ++
- ++ -
- ++ ++
++ +
- ++ -

-++ = hirlily rf'l'octive; I = oFf'ecctl ve control; = insufficient
control and In some cn;s(,; may provide no control. DM = downy
mildew; I'M =- powdery il I dow; Alt. = Alternaria leafspot; and
iL1S = uimmnv ;tcm bl1. t .


10. Squash Fungcllde Trial (llopkins)

Variety: Walth1l: m Bilutt, 'nut Squa:;h

Date of Plant.ing: March 1, 1984

Procedure: Treatment,; were applied April 20, 28, May 4, 11,
and 18. Sprays were applied at a pressure of 150 psi and in
100 gallons of dilute spray per acre, using a boom sprayer.


Disease rating1
Treatment and rate (amt./acre) DM PM
XE779L (0.2 lbs.) 4.0 cd 0 a
XE779L (0.1 lb.) 2.0 b 0.1 a
XE779L (0.05 lb.) 5.1 de 0.1 a
A-815 (0.25 lb.) 5.2 e 0.1 a
Allette (1.0 lbs.) 3.4 c 2.9 b
Bravo (2 pts.) 0.9 ab 4.2 c
Allette (2.0 lbs.) 2.0 b 4.6 cd
Bravo alt. with Vrinlcrt M 0.7 a 4.7 cd
(2.5 pts. & 2 q s.)
Bravo + Vinicur (2.5 pt:;. + 1 lb.) 1.0 ab 4.8 cd
Aliette (I4.0 lbs.) 1.2 ab 5.1 cd
Unsprayed 4.7 de 5.5 d

1Barratt-[Ilor;rall ratigs system: 0 = no disease, 6 = 50%
disease, 11 = 100% disease. DM = downy mildew and PM =
powdery mildlow. DM was rated on 5/10 and PM on 5/17.

11. Pickleworm Control Phytotoxiclty Test (Adlerz)

Purpose: 1.) To compare insecticides for control of
pickleworm on squash. 2.) To compare phytotoxic fenvalarate
(Pydrin) within new, non-phytotoxic 'ormulations of the same

Date of Plantl.in;: March 1, 1981

Varieties: Bilupeo Ilyblr)i1' and Elte' Zucchini squash

Procedure: Tr'atm';ricnt were applied weekly beginning April 24.
'Thlee spray n :;' wetr nountl;ed on an inverted u-shaped
boom to spr: y p lant',: fi'oim th;-e top and 2 sides. A minimum of
5 application.lS was mtde. PhytotloxI city ratings were made on
foliage after 3 a: li.ct:i on arid on foliage and fruit after
) appli cati !:n-. I'ck:l womwnn conrl.oiel Is evaluated by weighing
damaged arid undamaged fruit.

r- I ;I-

A. Ammo 2.' I1
13. Amuno 2.B' I:
C. Amino 2.' !I:
1). UnL treat(tL i
H'E. M0070610 1 .9 21' ( I'ten val t'at
F. M007061, 1 .'92'C
G. M00706]f 1.921C
11. < )DO1377') 2.4 1'C ( ,nvni rate1 )
1. SD130 377' 2. I'
J P'ydrin ). c (l Po,'llval, :.

For efficacy: A, i, C, E, ,J.

For phytotoxicity rating F, G, H., I.
applied to watermelon).

kate, lbs. a.1./acre

0. 015

(materials also

Results: No pickleworm infestation to May 14, 1984.
Phytotoxicity on watermelon and squash foliage from
SD043775 consists of a yellowing or whitening of the
leaf edges and interveinal areas of the youngest leaves.
Leaves recover. Rate effects are distinguishable on squash
leaves, but are less obvious on watermelon. Squash leaves
recover more slowly after high rates of application than
: Lter .1 ] w r;ll r;.

Toxtuity to cchlil f'riult was.; very mild. There were no
wat teiirelon fru itl, to observe ,t tIhis writing.

1Pydrin has performed well .in rDickleworm control tests at
this laboratory. The l'ydrin label cautions against use on
zucchini squash due to phytotoxicity. In the M0070616
foremulat on It appears th,;l. the toxic principle has been
effectively removed.

Recommended Innsecticilde f'or ,quash:

Materials and rate (jamoulnt/acre) )
Lannate or Nudrin 90SI', 1/2 1 lb.

Min. days1
to harvest
1/2 Ib 1
1/2 Ib 3

Carbaryl (Sovin) 80WP 1.2' Ibs. NTL

IMinlmum number of days allowed between the last foliar
applicat-ioin and harvest.
NTL = no t imii limit.

12. Cucurbit V'is ;__ Studies (Adlerz)

Occurrence o) Zucchlnl: Yellow Mosaic Virus in Florida

-1 1-

Previous st. nile: 1~tind1ca1ted that watermelon mosaic virus 1
(WMV-1) and wattc'rimeon mri:;alc virus 2 (WMV-2) were the viruses
most, commonly affect-iring U!:.'.rm -olon and wild cucurbits in
Florida. In watermelon, WMV-1 was most common in south
Plorlda nuid WMV-," was ,:io;'fI tlommon in central and north Florida.
The prevalanuec of WMV-1 in central and north Florida cucurbit
crops increan:Cd through 1the summer and fall. In the wild
cucurbits, only WMV-1 was found In Momordica charantia L.;
WMV-1 was the most common virus affecting Melothria pendula L.
and WMV-2 was detected I n frequentlyy.

Beginning in 1981 we detected a new virus in squash, that we
now recognize as zucchini ye-llow mosaic virus (ZYMV). ZYMV
has been identified from othi(, cucurbits in Florida including
watermelon, cantaloupe, (*ucuimibr, summer and winter squash,
butternut squash and the, wild crcurbit Melothria pendula.
Surveys of squash From 1981- L.')0 established that ZYMV is
widespread in li'orlda cuci rb tL:; and is a significant new threat
to this industry.

:',e' nal a d n -';!loartl dlsit;l'l.tih ont a i If C .Murbit viruses in Florida plantringsf;
ol' squash, Cucirb b La p L. Novel)err 1.981-September 1983.

Couity/Season WMV-1 WMV-2 /ZYMV 1;' 1+ZYMV 2+ZYMV Total of
samples taken

Sprin I I L 2 1 30
Autumn r 111 18 1 8I 83
1',.i m Beach
Spring 1.( 3 18
Autumn 1] 2 17
Autumn 3 1 10
Madi son
Spring 4
Spring -17 17
Autumn 1 19 8 2 38
I uni Iton
Autumn 2 2
Co I 1 er
011 ic2r
Spring .I 1. 23
A\utuil II 11

Spring 1) 19
Autumn I15
1:5 6J 82 9 15 1 287

'4TIV-i = watetn;s.lon mosaic virus-1; WMV-2 = watermelon mosaic virus-2;
ZYMV =zucchini yellow imos.ic vi.ru;. iucnuber mosaic virus was detected
in one sanirpl cllcctled in Alachua county in the spring of 1983.
YI iunber. of S' ,u:: 1 ':' c;'nta intii, g 1.1h virus indicated by the column heading.


ZYMV is a relatively inew occurrence wherever found. It
was described first I in TIaly In 1981 (and in France
s I iu.1 tanlot):t; ly :L:; m11I iu :l'ii ll- I', w s tunt). It ih ; been
reliably re orted from ;'r: 1;,, I, :)'oain, Morocco, (ermany,
and in the I:,A f'romrn ComirLti ut, Hew York, Cal iorn ia,
and Florida.

I'. \E.valuation )' watel'im'lot iiio;,i;Iic v.. ru:;-2 resistance in
Multipik sq ulas A-'( i -' ":., i'is"t-l. n 'T m, I urcifull)

Date of latlltli : Itl'.lu83'y, 1W83

Varieties: Haty 1'ro I fl.c >L aifghtn ck', Multipik'
cultivars of summer squash

Procedure: Varoetleos ini paired row;s, 9 hills per row,
8 pairs per bLock with i replicates

Treatments: Mechanical inoculation with watermelon mosaic
virus-i (WMV-1 Isolate ino. 81-75), watermelon mosaic
virus -2 (WIV-2 IsolaLt no. 151), zucchini yellow mosaic
virus (ZYMV Isolate no. 81-2 ), and no inoculation.
Tnocllat i.on Apri L 1I) or 18, ,Just before harvest.

Hs'.ults: i ''li on rl' plants was 97% or more in 'Early
'n'liflc ,>tlra'iJ it k' tItid .100% in 'Multipik'.

Although Mult inilk plants were 100% infected, note in the
rasph that tlhe fruit resisted WMV-2 symptoms. There was
no resistance to symptom expression of WMV-1 or ZYMV.

There was no resistani-ce to fruit symptoms from any virus in
Early Prollfic Stralghtneck (see graph).

On May 16, 1 plants each of uninoculated Early Prolific
.StUraiglitneck and Multipilk were sampled in each replication,
a total of 16 plants per cultivar. Extracts of these plants
containing virus were evaluated by SDS immunodif fsion assay
(a serologiical method). Virus infections in uninoculated
pl1antis were a;s follow: '.


Early Prolitic :;atraJititneck 1/16 1/16 13/16
Multipik 1/16 0/16 15/16

ZYMIIV appear;; to have a much greater potential for rapid
spread than WMIV-1 and WMV-2.

100- PERCENT "
4/29 5/6 5/1 I
UNTREATED 0-0 0 0 33
WMV-' *- 91 100 100
- 80- WMV-2 0-099 99 100
SZYMV B- 63 100 100

n 60-

c 40-

W 20-

4/18 4/20 4/22 4/25 4/27 4/29 5/2 5/4 5/6 5/9 5/11 5/13 5/16

MY 4c(v ; Ac

4/29 5/6 5/ I1
UNTREATED 0-0 0 6 35
WMV-' 0-- 15 97 99
WMV-2 0-C 12 97 97
ZYMV 3 97 100

Oj I I I ( ie--
4/18 4/20 4/22 4/25 4/27 4/29 5/2 5/4

P ( ; fz. f.

5/6 5/9 5/11 5/13 5/16

ZhruL(1L* ~vucwt'



U) 40

W 20

Oc M*


14. Watermelons Sensitive to Ethylene (Sherman)

Results of recent research indicate that watermelons should
be added to the list of commodities detrimentally affected
by ethylene (e.g. cut flowers, lettuce, cucumbers). L. A.
Risse and T. T. lHatton, of the USDA, Orlando, reported
that exposure of 'Charleston Gray' watermelons to as little
as 5 ppm CIH1 at 650F resulted in a decrease in flesh
firmness a d rind thickness with only about 50% of the
treated melons still fit for consumption after 3 days.
After 7 days of treatment only 10 20% of the C H4 treated
melons were acceptable for consumption compared to about
90% for the untreated controls. More recently, Mohamed
Elkashif, a graduate student in the Vegetable Crops Department
confirmed these results for both 'Charleston Gray' and
'Smokylee' watermelons. Ethylene treated melons had a
very water soaked internal appearance in addition to thin
rinds and other visible signs of senescence.

These results indicate that watermelon handlers should take
precautions to ensure that their melons are not unnecessarily
exposed to ethylene. Generally, ethylene is not a problem
during transport because most watermelons are shipped as solid
loads during peak seasons. However, during periods of low
volume from Florida, watermelons may be handled in mixed-
loads and, in fact, the Orlando studies were prompted by
reports of poor watermelon quality upon arrival at markets
during low volume periods.

35. Watermelons for the Future? (Sherman)

Watermelon consumption has fallen steadily from about
18.2 pounds per capital during the 10 year period 1946-55
to approximately 11.4 pounds per capital for the 1971-80
period. This represents a 37.4% decrease and should be
a major concern of watermelon producers. Why has this
occurred? What can be done to reverse this trend? What
will happen in the future?

Watermelons are considered a warm weather fruit, traditionally
associated with the fourth of July family picnic. In fact,
80% of all watermelons in the 1JU.S. are produced during June,
July, and August. To a large degree, this seasonality is
dictated by the warm temperatures required to grow watermelons,
but promotion efforts to increase consumption during non-
traditional months might be beneficial by making consumers
aware that watermelons are good anytime.

Sweetness, flavor, 'lo(hI color, and texture are important
consumer quality factors in watermelons. Sweetness (usually
objectively measured as % soluble solids) is probably the
most important; factor Influencirng consumer preference. The

sweetness of a watermelon does not Increase after harvest.
Therefore, It is extremely Important that melons are not
harvested until they have reached the desired maturity.
The U.S. Grade Standards allow the optional specification of
internal quality with "very good Internal quality" requiring
a minimum of 10% soluble solids and "good internal quality"
requiring a minimum of 8% soluble solids. In side by side
comparisons consumers peocr .i: tho sweeter melons. Those
concerned with increasing watermelon consumption should
require melons( with "very good internal quality" whenever

Statistics indicate that there have been numerous changes
in our population characteristics coincidentally with the
downward trend in consumption. Family size is smaller now
than 30 years ago. There has been a large increase in the
number of one and two person households and our population
of senior citizens has also increased.

When these facts about changes in the characteristics of our
population are combined with the lack of change in watermelon
size, a plausible explanation for the downward trend in
consumption emerges. Watermelons are simply too large for
today's households to consume except on special occasions
such as family reunions, picnics, neighborhood get-togethers,
etc. The major cultivars grown in the U.S. average more than
20 lbs. apiece-a weight nearly double the annual per capital
consumption. If one considers a 2 lb. slice to be a
generous serving, thun the purchase of one of these large
melons by a one person household (23% of all households)
represents 10 or more servings. Tn contrast to the quick
consumption which occurs at picnics and other special
events, these large melons must be stored for home consumption.
This is difficult because they take a great deal of room in
the refrigerator and if refrigerated for long periods,
quality is adversely effected by chilling injury.

Reversing the downward trend in watermelon consumption will
not be an easy task. Increased promotional efforts may
play an important role, but melons may have to be considerably
downsized (8-10 lb. range and maybe even smaller) before
consumption can be significantly increased. This represents
a tremendous challenge to watermelon breeders, growers,
shippers and handlers. New high quality cultivars need to
be developed. A change to smaller fruited cultivars would
probably require different cultural practices and certainly
would require modified harvesting and handling techniques.
In spite of these difficulties, there appears to be real
opportunity for entreprenuers who are prepared to meet the
challenge for the future.


16. Lightning Damage (Crall)

Lightning damage in watermelon fields is not a common
phenomenon, but it occurs frequently enough in Florida
to warrant persons interested in watermelon production
becoming familiar with symptoms of its occurrence. The
most prominent feature of a lightning strike is the
sudden wilting and death of all plants in the more or
less circular area of a strike. These spots are usually
found a day or more after electrically active thunder-
storms in the area. Perhaps the most striking confirm-
atory evidence of lightning damage is the occurrence on
the surface of the fruits of characteristic jagged lesions,
very suggestive in their appearance of lightning patterns
in clouds. Also characteristic of lightning damage are
necrotic lesions that roughly outline the white "under-
belly" of melons, indicating greater damage from conduction
of electrical current at the points of contact of the
melons with the soil. Internally, the rind area underneath
that in contact with the soil develops pronounced yellow
discolorations and the contiguous pink flesh has a water-
soaked appearance. Roots of affected plants are devoid of
the vascular browning that is typical of Fusarium wilt,
but do develop an overall light butterscotch discoloration
in contrast to the clean white appearance of roots of
unaffected plants. Two lightning damage spots occurred in
this year's watermelon plots in the vicinity of rows R4, 5
and rows T15, 16, both on the south side of the field.
We had a severe electrical storm in the area on May 23,
which seems to be the most likely date of occurrence'of
the lightning strikes.

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