Historic note

Group Title: Grape field day, University of Florida Agricultural Research Center
Title: Grape field day. 1983
Full Citation
Permanent Link: http://ufdc.ufl.edu/UF00075750/00003
 Material Information
Title: Grape field day. 1983
Series Title: Grape field day.
Translated Title: Research Report - University of Florida Institute of Food and Agricultural Sciences ; 83-1 ( English )
Physical Description: Serial
Language: English
Publisher: University of Florida, Institute of Food and Agricultural Sciences
Publication Date: 1983
 Record Information
Bibliographic ID: UF00075750
Volume ID: VID00003
Source Institution: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: oclc - 144618164

Table of Contents
    Historic note
        Historic note
        Page 1
        Page 2
        Page 3
        Page 4
        Page 5
        Page 6
        Page 7
        Page 8
        Page 9
        Page 10
        Page 11
        Page 12
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


S~3L)iCi U




JULY 19, 1983

Dr. Timothy ('rocker, Professur, PV''ult Crops Department,
University of Florida, presiding

9:30a.m. 10:05a.m.-- Registration and bunch grape fresh fruit
taste panel (all people in attendance are invited to rate
varieties for taste). Displays, grape products, and latest
literature on grapes will be available.

10:05a.m.-- Welcome by Dr. Cary Elnmstrom, Center Director,
Agr. Research Center, Leesburg.

10:10a.m. 10:55a.m. -- Discussion of grape research in progress,
including any new findings since the last Grape Field Day
(questions will be answered as they occur):

Dr. W. C. Adl.erI ;, Entomologist, 1,cesburg

Dr. D. L. Hopkins, Plant Pathologist, Leesburg

Dr. J. A. Mortensen, Geneticist, Leesburg

Dr. R. P. Bato'i, Food Sc.l. ntls;t, Gainesville

11: 0a.m. Noon-- A guided tour of the experimental rape
vineyards will be conducted. Included in the tour will be
a mist propagation unit, two screenhouses, an overhead arbor,
seedless bunch grape selections and other outstanding breed-
ing selections; new varieties Suwannee, Conquistador, and
Daytona; rootstock trials including the new Tampa rootstock;
fungicide tli ils, and other vi t i e li1 tural Items.

Because of yield records we ask thait tlaq':; and containers not be
brought on the vineyard tour.


(150 copies)


I. JUN Flid

!.F.A.S.-Univ. of Florida.

Tnsect Control on F Icidoan Hu nch ipc:' (W. C. Adlerz)

Many insects can be found on bunch grape; in Florida. Some can be se-
verely damaging and control may be necessary. To keep spraying to a
minimum, growers may wish to become acquainted with insects having the
greatest damage potential, inspect vines frequently, and spray only when
necessary. This is a good strategy, since preventive spraying will not
be necessary in most cases. Exceptions occur when growers experience
annual problems with grape seed chalcid, or if the grower adopts spraying
to control newly emerged root borer larvae in the fall as part of the
grape root borer control program.

Among the most persistent and damaging insects are the grape flea beetle,
grape leafhopper, and grape root borcr.

These are discussed briefly.

Grape Flea Beetle

Grapevines are damaged by adult and by larval grape flea beetles. Adult
beetles are dark bluish-black and about 3/16 Inch long. They are usually
the first insects of the growing season to damage grapevines. Adult
L.:c'tles feed on primary buds which then cannot develop into primary canes,
so crop yield is reduced.

Grape flea beetles breed in the vineyard, and females lay eggs on various
parts of the vine. Larvae are brown, spotted with black, and about 1/4
inch long. They feed on the unper surface of leaves and on developing
flowers and buds, reducing yields.

since both adults and larvae are easily seen, vineyards should be care-
rully monitored in the early season, paying special attention first to
,aine and then to flower buds. insecticides should be applied when neces-
:;s a ry .

Grape Leaf'hopper

;rape leafhoppers can he expected to infest vines each year. Adult and
immature insects feed on the undersides of leaves causing pale feeding
.,pots visible from above and even general discoloration. Vine growth
:nd sugar content of the grapes may be reduced and seriously affected
vines w:ll be weakened. Excreta irom these Insects may collect on the
V'ruilt which will then he spotted and possibly covered with sooty mold.

Grape leafhopper adults are light colored, about 1/8 inch long and very
acti.ve. Tmmatures are very small, often difficult to see, usually im-
nobile, but can be provoked to act v.it;y by touching.

W'n application of insecticides made r:ior to flowering and a second
2-4 weeks after flowering will result in good leafhopper control if one
oliets preventive sprjy itng.


Grape leafhopper control experiment, 1981.

Procedure: An experiment was designed to compare Orthene 75SP at 0.25,
().'), atnd 1.0 lbs. AJ/:acre and :.v i 8)0Wj' and Mesurol 75WI' at 1.0 lbs.
AI/acre. Applications were made to Lake Emerald grape, 4 plants per
plot, replicated 6 times. Insecticides were applied once op July 8 with
:a 'olo Jun.lor model 11 10 backpaclk, ml:; tb) ower. Evaluations were made by
counting leafhoppers on 10 leaves per plot at weekly intervals after

Results: All insect. ides were very effective in reducing populations
oft the leafhopper ('l'able 1). lResdual effectiveness of Mesurol and
".evin at 1.0 pounds AT/acre was sustained 2 weeks. Residual effective-
ness of Orthene was iistained at lenS t 5 week.

Grape Root Borer

:rape root borer may he the most serious threat to grapes in Florida,
having the potential to kill both bunch and muscadine vines. Larvae
tunnel in the roots, reducing root diameters and girdling even large
roots. Large larvae ofIten make their way into the crown of the plant.
Marked reductions in vine vigor and yield is cause to suspect root borer
activity. Detection is by exposing part of the root system to inspect
for larvae or damaged roots.

Larvae remain in the soil for about 2? months before coming to the sur-
face to pupate. In Florida, the adult; mrith:; are active and can be seen
in the vineyard in daytime, mainiiy in October. Adults are brown, wasp-
like moths with yellow markings. Females lay eggs on a variety of plant
materials or on the grund. Newly. hatched larvae tunnel through the
:ol to the roots.

control l methods may includee injection of insecticidal furigants into the
,;cu)1 and spraying ti ground to kill newly hatched larvae in late September
ind October. Larval control with !mrafco applied sprays has not yet been
-valuated in Florida. Control may be difficult. There are no legal
chemical controls at .his t.ime.

i4oot borers have been found in moI.; v;arlot le of grapevines in Florida,
(Table 2).

either insects or daimace commonly seen.

,rape leaf folders, grape leaf skeletonizer:;, grape leaf miners, grape
phylloxera, grapevine aphids, and anomala beetles are commonly seen in
the vineyards.

All are considered minor pests that may not require control efforts.
,;rape leaf folders and skleotonizers may be especially abundant in the
late summer and fall. :;klcotoni her'ss (brightly colored yellow and black
triedd larvae feeding; In groups) should not be allowed to denude vines,
,o they should be sprayed if necessary. If foliage disappears, remaining
foliage is smeared wit.,h black frass, and rno insects are seen, look for
nnomala beetles under vi, Ins, or look f)r i::;ct;s eat ing foliage at night.

Table 1.

Leafhoppers per 10 leaves from Lake Emerald plants tested with insecticides July 8,
1981 at the ARC Leesburg Farm.

Leafhoppers/10 leaves
Treament Formulation AI/acre treatment
7/1/81 7/22 7/29 8/5 8/12 8/19 26

thee 75 1.0 7.2 a 3.5 a 1.- a L.0 a 1.2 a 5.2 ab 2.3 a
rthee 75 SP 0.5 7.2 a 3.2 a 1.2 a 0.s a 1.0 a 2.5 a .5 ab
rthene 75 S? 0.25 7.3 a 2.5 a 0.8 a 1.8 a 1.8 a 5.L ab .8 ab
Sevin 80 T? 1.0 7.5 a 3.2 a 4.0 b 4.3 b 2.3 a 6.5 bc 6.3 b
7.esurol 75 WP 1.0 10.7 a 1.5 a 3.8 b 5.5 b 5.8 b 9.5 cd 10.2 c
Untreated -- -- 7.2 a 14.3 b 14.5 c 117 c 7.0 b 12.0 d 11.3 c

Occurrence of grape root borers on various grapes in the
laboratory research planting and a commercial vineyard:
cast pupal ski.n at, Il, ;ol 1 :nrrace.

Pupal skins per
__19 7) 1980 1981.
libertyy (Lake Emerald)
Stover (Lake Emerald)
Blue Lake
Lake Emerald
Norris (Lake Emerald)
L4-33 (Dogridge)
Southland 0.0 0.5 0.4
Magnolia 0.0 0.; 0.0
Thomas 0.2 0.3 0.6
Redgate 0.2 0.8 1.0
Chief 0.2 0.0 0.5
Regale 0.3 0.0 0.0
Magoon 0.5 0. 0.3
Tarheel 0.7 0.3 0.6
Welder 0.8 0.0 0.6
Water, ate 0.8 0.0 0.0
i'ry 0.8 0.3 0.5
Creek 0.8 0.0 0.3
Dixie 3.2 0.3 0.8
Dearing 1.2 0.3 0.0
uIumbo 1.3 0.0 1.3
I2 2- -1 2 2.;2 0.; 0.5
Cowart 2.2 0.0 0.6
Noble 2. 3 0. 0.8
Hunt 2.3 0.6 1.4
Sugargate 3.3 0.3 2.6
Carlos 3.6 0.2 0.0
Ii ggins 4.0 0.0 0.7

Average from 6 s in.,gl-planL treo! LiecaLionr.;
2Average from 5 to 15 plan o h variety.
Average from 5 to 15 plans of each variety.

1980 1981

0. 4
0. I
















Table 2.

Whein Lo spray

1 Tn:ec t .d for i.1 Bunch G!rapeo
111 sec t c.1 de

Bud break to flowering:
(or later for beetle)

Pre-bloom and
2-11 weeks after bloom
Late April through
May, weekly
I'ost harvest

As needed

No controls available

Malathion or
Methoxychlor or
Carbaryl (Sevin)
Methoxychlor or
Carbaryl (Sevin)

Flea beetle


~Malathieon Seed
(as above) Leafhopper
Malathi.oll Aphids
Methoxychlor Leafhoppers 2
or Caterpillars
Carbaryl (Sevin) Fruit beetles
Root borer



IMe thoxychlor

1.5 pints 57% emulsifiable concentrate/100 gal. water
1.5 teaspoons/gallon
Days before harvest 3
2 pounds 50% carbaryl wettable powder/100'gal. water
2 tablespoons/gallon
Days before harvest 0
2 pounds 50% methoxychlor wettable powder/100 gal. water
2 lablespoons/ga] lon
Days, before harvest 1I

Wlhei tlls insect is a problem preventive spraying will be needed.
'(;rape leaf folder, lear skeletonifsocr, hornworms, berry moths.

' Jia e Funglcide Tosts (1. L. Iop)k ini:;)

Fungicides were evaluated for their effectiveness on grape diseases in
the ARC, Leesburg vineyard. Treatments were replicated 3 or 4 times in
the tests and each plot consisted of 3-5 vines. Each year treatments
began the third or fourth week of March and were applied every 2 weeks
until harvest. After harvest, treatments were applied every 3-4 weeks.
Approximately 150 gallons of spray per acre was applied.

Tables 3 and 4 present the results of 1980-82 tests in which the current-
ly recommended fungicides were applied in various combinations. The
compounds were either tank mixed (+) or applied on an alternating basis
(all.). Table 5 presents results of a 1982 test with 3 compounds not
currently used on gr'ap1evines in Florlda.

lH-sease Control of Fl.orida Grapes (1) Hopkins

Disease control is an absolute necess-Lity to successful bunch grape pro-
duction in Florida. ''lhe most severe I'urvnal disease is anthracnose, which




Tab le 3. Control of :aitlln'actno;e () I ''.lw.1 i da i'ra vines, 1980-82.


I'lt.litan alt. Mandate D
P'haltan alt. Benlate
Ortinholde + Manzate D
Bcnlate + Manzate D
Orthocide alt. Manzate D
i'la!tan alt. Benlate
+ Manzate D
Mu:a, ate D
ienilate + Orthocide
iknlal:te alt. Manzate D
in::; prayed

AMil./ 'Acre

'V4-36" (7/80)

11.0 1b;. 2.0 1)b;.
4.0 lbs. 1.5 1bs.
11.0 lb;. + 1. r It)r.
1.0 lb. + 1.5 Lbs.
11.0 lbs. 2.0 -lbs.
1. 0 lb),. 1.0 11) lb.
+1.5 lbs.
2.0 11.); .
1.0 l.b. + 3.0 lbs.
1.5 lbs. 2.0 lbs.


4. 4


rating (0-10)
"Stover" (7/82





Table 4. Control of fruit rots of Florida grapes, 1981-82.


'haltan + Manzate D
Benl ate + Manzate D
:'haltan alt. Benlate
+ Mandate D
'I : 11,an ;alt. Manzate D
'!t hlocide + Manzate 1)
I;en la .: altL. Manzato I)
Boenrlate + Orthocide
I )'i.loc 1ide aalt. Manzate
b1enIato alt. Phaltan
Man:'ate D
)i'ltoculde alt. Phaltan
'Ins- rayed


% bitter rot
on 'L9-11'

% anthracnose 8
black rot on
'Stover' (1982)

3.0 lbs. 1- 1.5 Ibs. 11
1.0 1b. + 1.-5 lbs:. 14 13
1.0 lbs. 1.0 lb.
+ ].5 1bn. 6
14.0 1b 2.0 -, 21 7
4.0 Jb + 1..5 ib 7
1 ) I) 2 .0 H 1 ;. 18
1.0 lb. -1- 3.0 lbs. 20 10
S 11.0 b:; 2.0 Ibs. 10
1.5 lb.. 1.0 b.s. 19
2.0 lbs. 25 19
)1. (0 bs 0 1 )b: 33

"ab e 'i. Preliminary screeonlln test of fungicides on Florida



rating (0-10)

% fruit rot
(anthrac. &

Ba:,cor + Agridex 1.0 lb. + 1 pt.
\ inlcur M-2C 2.0 gal.
'eronate + Manzate D 1.0 lb. + 1.5 lb
!aylJeton 3.0 oz.
i":leloton (;8 day interv:,l) 6.0 o:.




__I_~ ~_


------~ ----
~---- ---



,tl'l.'c!ti In).!il ol].ljg: :t* l 'ptii Tiiu'r : ', c other' [urinal fi r'ots -
black rot, ripe rot, and bitter rot that must be controlled. A number
of leafspot disease; biomno seriouss ir-b ji on during late summer. These
diseases must be controlled to prevent premature defoliation in the fall,
thus assuring a stronger vine :in dormancy nnd better yields the following
,y e.ar'

A long growing season, hLgh temprratul .'u:, abundant rainfall, and high hu-
midity make bunch grape disease-s very difficult to control in Florida.
Therefore, a vigorous spray program must be started in the spring when buds
ar'e 2-6 inches long amid contI nued tlhro(uglut the :eason. Fungicides should
be applied every 10-14 days until a week before harvest, and every 3-4 weeks
from harvest through fNove,,bet' or iuntil, I lo'mr;cy.

sincee muscadines are resistant to anthracnose, the first spray can be de-
layed until just prior to bloom. As with bunch grapes, fungicides should
be applied every 2 weeks through harvest. One or 2 postharvest applica-
tions are beneficial. The fungicides recommended for grape disease con-
trol in Florida are listed in the following table. A spreader-sticker may
be included in the spray.

Amt./100 gal. Amt. per Days before
Fungicide per acre gal. harvest

Mandate D 1 /2 lb. 1 1/2 TBS2 7

Pithane M-22 Special 1 1/2 lb. 1 1/2 TBS 7

S'ap tan 2-t lb. 2-4 TBS 7

hnlt an 2-11 lb. 2-4 TBS 7

eBnlat- 1-1 1/2 i. 1-1 1/2 TBS 7

Thi.s is the recomme ndeId minimum number of days between last application
of fungicide and harvest.
':TB.3 = tablespoon.

WUIed Control in Flor:ida Vineyards (J A. Motensen)

rine of the secrets of successful grape growing is an integrated program of
~.eced control involving mechanical tools, herbicides and mulches. Weed con-
trol between vine row:; is; much eas.ler to accomplish than that under the
trellis itself. Herbicides are rarely used for weed control between rows
since mowing, diskintg, or rototilling, are more practical and less expensive
bot hi Ln young vineyatrc; and mature vi cnyard (;. The discussion below con-
cerns control of weeds in the vine row where disking and mowing are not

Young vineyards. Mulching, with 3 inches of oak leaves or pine
neicdles around each newly set grapevine helps control weeds and conserve
:oil moisture. Hoeing of weeds in small vineyards is usually replaced by


herbicide spraying in vineyards one acL'e or larger. Paraquat kills all
the leaf surface it1; vers, .I ine l: i1ng g 'apevrine foliage. A tractor-
mounted boom with a nozzle *;ur'ounded by a cone-shaped shield to pre-
vent drift of spray In windy weather is effective in directing the
mi:itei'al to a band a1lol ng each side of' tlihe -()ow without getting on the
grape plants. Sufficient overlap of spray bands between vines in the
tow i; essential to avoid cleavlii,; a green strlp of weeds under the
trellis wires. HIerbilcLdes may need to be applied early in the morn-
iril or late in the afternoon to avoid mid-day windiness. Also, spray
when cf'orecast for ;owe I; ls tos t 1lan 5U%. Dalapon herbicide con-
tiols grassy weeds. Apply in April or May, or when the grass is green
and actively growing. Avoid spraying the grapevine foliage or on bare
i(-ound. Roundup (Glyphosate) weed killer gives excellent control and
cran be sprayed on actively growing weed leaves, but severe injury to
vinros can result if any gets on grape leaves. In Stoneville, Miss.,
a wipe-on attachment was developed for use with Roundup, with a wick
for keeping the material available. This is safer for vines than
spraying. Surflan can be applied on young vineyards as a pre-emergence
weed control.

Mature vineyard; (3 years or older)). Karmex (Diuron) herbicide
i: an effective pre-emergence herbicide if applied once a year, usually
in March. Weed growth occurring In the rows in mid- to late summer can
be burned down with Paraquat herbicide, hoed, or sprayed with Roundup.
P:lapon is effective on grassy wedrs such as; Bermuda grass sod. Do not
mix Dalapon with othel herbicides In the spray tank. Karmex and Paraquat
may be mixed where both a pre-emergence and "burn-down" of existing weeds
:re needed at once. Thorough cleaning of spray tank, hose, and nozzles
l1y draining, flushing, and cleaning with detergent are recommended fol-
lowing the use of herbicides. Roundup can eliminate weed growth for two
or three months, whereas weed regIrowth occurs within three weeks with
Sra qu'at. A tank mix of Surf'lan anrd Roundup has proved effective at
A.11.C., Monticello for pro-emergence and "burn-down" control.-

liorb icides ( uIsed for grapes

Amt. o' X-77
I product Rates, used Spreader Specifications
ara :uat 1 qt./50 gal. 4 oz./50 gal. Wet above-ground portion
4 tsp./Fal. 1/2tsp./gal. of weeds whenever needed
(3 to 5 tires a year).
nlanon 5 lbs./'0 g7al. o1 oz./50 gal. Wet leaf surface when
0.1 lb./gal. 1/2 tsp. gal. grass is actively growing
(twice each year, 3
weeks apart).
,:rmex ,80W 3 lbs /sprayed None required Wet surface of ground
acre. evenly in a band on each
2 tsp./gal./ side of row (once each
100 :;. fL,. year, usually March).
Vines must be 3 years old
and 1 1/2 inches trunk

Amt. of X-77
I'_oduc t Rate _lIH:d '"'proa' ... Specifications
Surflan 75W 4 lbs./:;payed None required Safely sprayed right
(oryzalin) acres after planting2. Irrigate
after application if 1/2"
rainfall does not occur.
H oundup3 4 lbs./;prayed None required Wet weed leaves but care-
(n yphosate) acre fully avoid spraying
4 Tbs. + 2 top. grapevines.
per gallon

aCaution: muscadine grapes are subject to injury by Dalapon if the ground
is bare and the material is taken up by the vine roots.
Some vine damage may occur on coarse sands if heavy rains occur after
Roundup phytotoxic effects to grape leaves can easily occur- in drifted
vapor within 25 ft. of the spray nozzle. Use of low pressure and an
herbicide type nozzle is essential.

Irrigation of grapes (J. A. Mortensen)

Research on irrigation of grapes In Plorida is very limited. A one-acre
block of muscadine grapes was planted in 1974, and in 1976 was divided
into 6 blocks -- 3 microjet-irrigated and 3 non-irrigated. All irriga-
tion equipment was donated by Southern Citrus Nurseries. Corporation, Dundee,
iForida, who sell Microjet irrigation systems. Results in 1977 showed
:i 64 increase in yield and an 83% Increase In weight of prunings (Table
)1. 1977 was a relatively dry year which accentuated irrigation effects.
In 1978 only 19% increase in yield was obtained, but an 86% increase in
pIunling wood. 1978 had more rainfall, so the advantage of irrigation was
less marked. In 1979 there was a 12% reduction in yield in the irrigated
compared with nonirrig'ated blocks, the pruning weights were 34% higher in
the irrigated plots.

Varietal differences in response to irrigation were evident (Table 7).
'Welder', 'Fry', and 'Tarheel' were the most responsive to irrigation
in all 3 years, whereas 'Jumbo' and 'Southland' were relatively unre-
sponsi ve.

Pruning wood weights also showed varietal differences (Table 8), with
ilggins', 'Regale', 'Tarheel', and 'Doreen' showing the most increase
from Irrigation and 'Carlos', 'Jumbo', and 'Dixie' showing a decrease.

.icrojet irrigation appears to be superior to drip irrigation in that
either dry or liquid fertilizers may be used, whereas with drip systems
only liquid fertilizers can be used. It is recommended that the conduct-
rin tubes along each row be elevated by stakes or other support systems
10 n height of 12 to 15 inches to reduce 1 in breaks and interference of
water distribution.



'Table 6. ECfects of' mi-crojet i.rrig1at ton in a one-acre block of
muscadine grapes planted in 1971.4.
Fruit loelds (Ib/vlne) Pruning wts (1i
I ncr.
Year Irrig. iJon-Irr. (%) Irrig. Non-Irr
1977 17.3 10.3 7.7 4.2
1978 35.1 29.5 19 8.0 4.3
1979 40.0 .15.4 -12 7.5 5.6
Mean 30.8 7? .--1 7.7 7



Table 7. Yield increase due to mi crojet irrigation of 12 muscadine
cultivars planted in 1.9974.
Pounds per vine 3-yr
Cultivar 1977 1978 1979 Total Tons/Acre
Welder 9.1 11.9 T77. 38.8 4.5
Fry 12.3 12.9 10.0 35.2 4.1
Tarheel 6.8 13.7 6.3 26.8 3.1
Higgins 20.4 12.3 -10.4 22.3 2.6
Carlos 5.0 7.4 8.9 21.3 2.5
Noble 18.0 7.0 5.9 19.1 2.2
Cowart 7.2 8.9 2.4 18.5 2.2
DIxie 8.1 7.1 1.8 13.4 1.6
logale 14.9 2.6 6.2 11.3 1.3
I)oreen 10.0 4.7 9.1 5.6 0.7
Jumbo 6.2 1.0 6.7 0.5 0.1
Southland 0.8 0.9 2.1 3.8 -0.4

Table 8. Pruning wood weights from 12 muscadine cultivars with and
w.__ without mincrolt irril'at1.on. _____
Pounds per vine
1977 1978 1979 Mean
u'ltivar Irr. N.I. ]rr. N.I. Irr. N.I. Irr. N.I.
Higgins 13.2 7.3 10.6 6.1 7.1 10.8 10.3 8.1
iegale 12.4 4.5 8.4 7.9 7.2 9.4 9.3 7.3
"arheel 8.1 14.4 6.0 3.9 7.2 7.9 7.1 5.4
Doreen 6.7 4.5 8.6 6.3 9.6 9.6 8.3 6.8
'Joble 8.9 '1.5 8.4 6.0 6.7 9.9 8.0 6.8
Welder 5.4 4.0 6.5 5.4 7.2 6.7 6.4 5.4
'wa ; 4.6 3.2 4.9 4.2 6.9 6.5 5.5 4.6
:_outhland 2.8 1.9 3.1 2.5 5.5 5.4 3.8 3.3
!'y 7.0 2.2 6.4 7.9 4.6 6.7 6.0 5.6
i'arlos 16.8 9.5 11.2 12.7 4.8 13.8 10.9 12.0
Jumbo 10.1 5.6 8.3 9.8 7.1 14.0 8.6 9.8
;)1x e 10.4 6.5 7.4 8.3 7.8 15.6 8.5 10.1

-- i



Fertilizer N-P-K Factorial ExpririImnt (.T. A. Mortensen)

A ratio of 3:1:2 or 3:1:4 was apparently superior to the 1:1:1 ratio of
N:P:K for grapes. However, dlfrl'ioencor were not statistically signifi-
cant for yields or weight of dormant pruning wood. Under conditions of
no irrigation, the growth and yield of Blue Lake and Norris bunch grapes
were greater where clay was 2.5 to 5 .'t. below surface than where it was
5 or more feet deep.

Breeding grapes for Florida (J. A. Mortensen)

An active breeding program with grapes has been continued since 1945,
when Loren Stover made the first significant cross. The emphasis was
on bunch grapes until 1972, when muscadine breeding was also included
in the program. New varieties coming from the program are as follows:
Lake Emerald (1954), Blue Lake (1960), Norris (1966), Stover (1968),
Liberty (1976), and Dixie (1976, jointly with N.C. State Univ.). A
number of both bunch and muscadine selections appear promising, and
best ones should be released in the near future. A rootstock to re-
place Dog Ridge was released in 1982 under the name 'Tampa'. No seed-
less selections are ready yet, but more emphasis on seedless grape
breeding has begun. Efforts to transfer seedless genes from bunch
grapes to muscadines by way of bunch-muscadine hybrids are being made.
P9-15, a fertile bunch-muscadine hybrid being used as an intermediate
carrier of seedless genes, can be seen on the tour.

ThIe State University System of Florida offers education programs to all
people without regard to race, color, sex or national origin.


University of Florida Home Page
© 2004 - 2010 University of Florida George A. Smathers Libraries.
All rights reserved.

Acceptable Use, Copyright, and Disclaimer Statement
Last updated October 10, 2010 - - mvs