Group Title: Grape field day, University of Florida Agricultural Research Center
Title: Grape field day.
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 Material Information
Title: Grape field day.
Physical Description: Serial
Publisher: Agricultural research Center.
Publication Date: 1982
 Record Information
Bibliographic ID: UF00075750
Volume ID: VID00004
Source Institution: University of Florida
Holding Location: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: 144618164 - OCLC

Full Text

1, (vL

61_ 3

Dr. Timothy Crocker, Professor, l'rlt Cropn Department, University of
Ilorida, presiding.

9:30 a.m. 10:05 a.m.

10:05 a.m.

10:10 a.m. 10:55 a.m.

11:00 a.m. Noon

-Registration and muscadine cultivar fresh
fruit taste panel (all people in attendance
are invited to rate varieties for taste).
Also, insect di:;plays, literature, Juices,
and other grape products will be available
for viewing or sampling.

- Welcome by Dr. Gary Elmstrom, Center
Director, AHC Leesburg.

Dicussion of grape research in progress
(including questions answered):

Dr. W. C. Adlerz, Entomologist, Leesburg
Dr. D. L. Hopkins, Plant Pathologist, Leesburg
Dr. J. A. Morte nsen, Geneticist, Leesburg
Dr. R. I1. Bate:,,, Iood Scientist, Gainesville

A guided tour of' experimental grape vineyards
will be conducted. Included in the tour will
be a mist propagation unit, overhead arbor,
effect of ethephon on ease of harvesting,
mechanical harvesting into catch frame, machine
for applying herbicides to vineyard rows,
screenhouse experiments, cutting nursery, and
new selections and cultivars of muscadine grapes
in fruit. Characteristic damage from insects
or diseases occurring in the vineyard at the
tLI lrm wi.1 ble (o)h(t'ved and discussed.

Thl public .is invited to attend the Cr-aple I''ild1 Day, and we welcome all who
i11 r into 'e o ed. Since yie ld rIecord;; ;ire t( ig ,obtai ned in the vineyards( we
isk that bags or container not be carried on the tour.

IlB':D tIR ARC :RESEA CH RI'(ORT ,1 (082-3 (180 copies)

\ ,,4 -T RAPE l LD AY
S c. N .-. ICj 4j iT 0 R I DA9, IP'AS
F "jAiJOiTf-l9 1982

Insect; Control on Florida lunch pt (Grapes (W. C. Adlerz)

Many insects can be found on bunch grapes in Ilorida. Some can be se-
verely damaging and control may he 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
rape root borer control program.

Among the most persistent and damaging insects are the grape flea beetle,
)grap' leafhopper, and grape root. borer.

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
I the filr't Insoects or1' thO growing L;,anon ,), lrnago grapovines. Adult
beetles 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 :;urrac' of leaves and on developing
S'Lowers and buds, reducing y 1i lds.

sincee both adults and larvae are easily seen, vineyards should be care-
Cully monitored in the early season, paying special attention first to
cane and then to flower buds. Tnsecticides should be applied when neces-

Grape !,a I'lopper

ri'ape leafhoppers can be expn;t'd to Inr',nt vines each year. Adult and
immature insects feed on the underside:; of leaves causing pale feeding
spots visible from above and even general discoloration. Vine growth
:n<1 sugar content of' the grape: may he reduced and seriously affected
vines will be weakened. Excreta from these insects may collect on the
fruit which will then be spotted and possibly covered with sooty mold.

Grape le-afhopper adults are Li ght col.oroed, about 1/8 inch long and very
active. immatures are very small, often difficult to see, usually im-
mobile, but can be provoked to 1, .c l v 1 ty by touching.

A\r application of insect.lct des: madi.; pior' to flowering and a second
P-4 weeks after flowering will result in good leafhopper control if one
elects preventive spray rig.

Grape lafho'lper crontrcl experiment, 1981.

Procedure: An experiment was designed to compare Orthene 75SP at 0.25,
0.T, and 1.0 lbs. AI/n ero, and Sevin 80OW' and Mesurol 75WP at 1.0 lbs.
Al/acre. Application:; wo 'e made to l,akei. l;ri,~rald grape, 4I plants per
plot, replicated 6 time:;. Insect, is c ide wir' applied once on July 8 with
a Solo Junt r model I Iln Ibckpack ml ;tbl owr'. Evaluationsr woro made by
counting leafhoppers on 10 leaves per plot at weekly intervals after

results: All insecticides were very el'fect, voe in reducing populations
of the leafhopper (Table 1). Residual effectiveness of Mesurol and
Sevin at 1.0 pounds AI/acre was sustained ; weeks. Residual effective-
ness of Orthene was sustained at least 5 weeks.

Grape Root Borer

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

[,arvae remain in the ;o.ll for about 22 month be fore coming to the sur-
face to pupate. In FlorlIda, the adult, moth; are active and can be seen
In the vineyard in daytime, mainly in October. Adults are brown, wasp-
like moths with yellow markings. l'emales lay eggs on a variety of plant
monte rlnas or on the ground. Newly lhatch:lcd larvae tunnel through the
:,il to the roots.

Control methods may include injection of insecticidal fumigants into the
soil and spraying the ground to kill newly hatched larvae in late September
and October. Larval control with surface appli 1ed sprays has not yet been
evaluated in Florida. Control may be difficult. There are no legal
chemical controls at this time.

Hoot borers have been found i n ( mo0 t v; r'i .ar i '; of grapevines in Ilorida,
(T'Lable ).

Ither insects or damage commonly ;(,.'fi.

rape leaf folders, Irape leaf skeletonuri t o; grape leaf miners, grape
phylloxera, grapevine aphids, and anomala be ,otles are commonly seen in
the vineyards.

All are considered minor posts that may not, require control efforts.
rape leaf folders and skel.etoniz err may be especially abundant in the
late summer and fall. Skeleton ers (brightly colored yellow and black
A; tilpod larvae feeding .in groups) should not be allowed to denude vines,
so they should be sprayed if necessary. If foliage disappears, remaining
collagee is smeared wiLh black 'ras:, and no insects are seen, look for
anomala beetles under vines:, or look for in:eocts eating foli ago at night.

-able 1. Leafhoppers per 10 leaves from Lake Emerald plants tested with insecticides J'-ly 8,
1981 at the ARC Leesburg Farm.

-leafh rs/ le-aves
--' --- i. S
ea -.en: Fru.lation AI/acre treaz-men:
7/1/81 -/22 "/29 8/5 8/12 /1 /2

rthee 75 S? 1.0 7.2 a 3.5 a .a 1. a 1.a at 2.3 a
rthe e 75 S? 0.5 7.2 a 3. -.2 a .8 a 2.5 a .5 a
rthene 75 SP 0.25 7.3 a 2.5 a a a 1. a 1.3 a 5.8 ab 4.3 ab
ein 80 "?. 1.0 7.5 a 3.2 a -.0 b 4.3 b 2.3 a 6.5 bc 6.3 b
:esur:l 75 'T? 1.0 10.7 a 1.5 a 3.8 b 5.5 b 5.t .5 d 1.2
-treated -- -- 7.2 a 1".3 b 1-.5 c 11.7 c 7.0 12.3 d 11.3 c

Table 2. Occurrence of pfrape root boo),':; on various grapes in the
laboratory l'' arcli p)l.atltl. ;1.1 nd a commerce T.a vin (:y:ard:
cast pupa.L skins at the soil surface.

I'u[aIL. :;kin per'
fabora 1, o ry
1'97 9 1o "980 1981

Co rnm e r c i.a
19B-o0 197f1

Liberty (Lake Emerald
Stover (Lake Emerald)
Blue Lake
Lake Emerald
Norri ; (Lake IEmn.eral1d)
L4-33 (Dogridge)
Chi ef
We] der

u: I., e ",: c

D x i e
Deart ng
u mbo
l l;]]l,2--i 2?

("i1 i'1 o
II IP i ns

! Average rom 6 s 1 I1':

0.0 0.
0.0 0. 0
0.'2 0.
0. 2 0. 8
0.2 0.0
0 0.0
o 0 ,

( 0 .
0 8 0 .

a I 0 1;
1.2 0..
S. 2 0. .

3 .. ;
3 )0.

4 0 0 0

'- ;lanLt I'c i c,'.l Ion;;.

A\vo)erage from 5) to 0 I plant; )' eacht v:warity.

0. i


0. 4
0. 4


0. 4






0. 3
0 .1.
0. 5
0 3
0. 8
.1 .3

0. 8

2. 0








r -(-

I O:001. 1 0 1 (j('2 ru~ n biJIi(h C r'pes
I i:.('(l i I

1, ~ ~;

ulld bWnk to floweriI'
(or later I'or bcot le)

I're-blooni and
2-4 weeks after bloom

VMe bli1o.)xy (' 11 i '0 a ['h1oppf r
('a rl a yl (Cvir n)
orx l It'l O O Lopper'
Carbaryl (Scvin)

chal cidI

Mav weeklly
iPos 1 btaravs t

(5 abov _) Leaf hopper

M. alath 1 o _
Carbaryl (Sovin)

No controls available

Aph .ds
Leafhoppers 2
Fruit beetles
Root borer

I', aI thion ] .r pints e57% emulsifiable concontrate/100 gal. water
1 toeaspoon:s/alr on
Day:; bel'o',e harvest; 3
Crbaryl 2 pounds 50%, carbaryl wett;able powder/100 gal. water
S L.:)'l e( poun) /gal 1 on
Days before harvest 0
' thloxychlor 2 poundss 50% methoxychior' wettable powder/100 gal. water
2 t ablespoons/!gallon
Day:: be fojre hatrovs, )1
Whl nl th l 1;'ecl, i;,; : I robl i i r vo'i'l i /in will e nrlooded.
i' ,pe lo'af folder', o ';i ;,ko l t oin :,'' Iitr'riwo 'rn;', beorry moth,.

;;pe il'ung'i c (i de T'I sl.: ( ). i. Hop! n,.:)

FuilwiC .-does were evaluated l'o' lle' ir fo'l ,i venIss on grape diseases in
1.,t1 ARC, ,eesburg vi neyard. Tre atrnenti;;r wor'n replicated 3 or 14 times in
t ie tests and each plot cons.isted o.' 3-15 vines. Each year treatments
b), i the third or fourth week of Marchi and were applied every 2 weeks
unt 1 harvest. After harvest, treatments, were applied every 3-11 weeks.
Appr'ox.i lately 150 go I Lons of ;pay per' acre was.:; applied.

'i';ible; 3 and I/ pro: ent the r',onul.;; of' 1 )9 0-8(1-; l,es1,:s in which the current-
ly i'commended fungll' i dest were app l l ed in vai (ous combinationss. The
r.mpound woer ellt .h tank mixed ( +) or appl I dO on an alternating banl.s
1i.1,.). Tab e 5 pr'1ent os ll,:; of a'. I test with 3 compound; not
Iur' .'t .ly useIj d 1on );l'' | 'v i 11 !i ,l'1ida .

II.;e ase Control of Florida ;ripn( (IP. I,. HIopkir ns

m ]"oa'e control is anl a)h ol ute (nec' (: i t,y 1,o :u(ce.; f'u I b' unch &rape pro-
,lu'!t ion in Plorida. ''e most s'V e t l'ui;',al di( :ease 1; antilhracrino.;e, which

As needed

P (;; .I,

IT' l.'i l. l i o i n

P'hhlo 3. Control of ;,nulracno; o()' Ilo'I d. fr'n 'vines, 1980-82.

Amt, /Actt

Anthracnose rating (0-10)
1 7IV -T TC---"0 to ve r'-rT7

I'lill;an alt. Manzat;o D
I'alLtan alt. Benlate
)IrlhocIde + Man: ate P
lienlate + Manzate D
Orthocide alt. Manzate
Ph''l tan Bonlate
+ Manzate D
MaInate D
lBoilat;e + Orthocide
rienlate alt. Manzate D
hpi rayed

1.0 1 h: 2). I t:
4.0 1b;. 1.5 lbs.
I1.0 :bs. + 1 .5 1 s.
1.0 )b. + 1.5 I h:;.
i) 4.0 lbs. 2.0 lbs.
1 0 1 1ws 1 .0 lb).
+1.5 ibs.
2.0 lb:;.
1.0 lb. + 3.0 1h;.
1.5 lbs. 2.0 lbs.

Table 14. Control of fruit rots of Florida grapes, 1981-82.


!'haltan + Manzate D
iLeiIl:ite + Manzate D
l'hal .an alt. Benlate
+ Manzate D
'hi lt. n :m lt. Manzate D
Orthocide + Manzate D
i('.1e late all. Manzate D)
lienllate + Orthocide
)rthocide alt. Manzate
!ial ate alt. Phaltan
1 lan/Sate D
'etr'hocide alt. Phaltan
Inl;,pray ued


% bitter rot
on 'L9-11'

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

3.0 lbs. + 1.5 Ibs. 11
1.0 l.b + .I lbn;. 1I 13
11.0 lbs. 1.0 ]b.
+ 1.5 .Ibo. 6
11.0 11),. 2.0 1 hI 21 7
1.0 Lb + ..L) lb 7
1.5 lb ;.0 lb. s. 18
1.0 lb. + 3.0 lbs. 20 10
D 41.0 Ibs. 2.0 Ibs. 10
1.5 Ibs. 4.0 1b:,. 19
2.0 Ib 25 19
4.0 Lbs. 4.0 ]b;. 33

Table 5. Preliminary sc or nenin-r tes;t nf f' Il (id('; on Florida


Treatment Amt./Ac re

i',.:I or + Agrldex 1.0 lb. + 1 pt.
' i i il sl' I VI -2, ,'.() a I;..
irenlate + T1ii.:.tte D 1.0 lb. + 1.5 1bs .
, ay Ie (ton 3.0 oI.
iPayJltotn (28 day Inte'rval) .0 ou;.

eating (0-10)



% fruit rot
(anthrac. &

4.7 41

II 0
4. I


1 I4




14 It



~__1_11 1 ___ __I_~

I- -
I ----------

'Tl' ;I t me I tt

'-_ .-

: Il''c!(, Iboth ol lar],, :lldI I'i'li l, t, '' :P i ', I n tjC r ungja l f'r'ul.t rot.; -
black rot, ripe rot, arid bitter rot that must be controlled. A number
of leafspot diseases become serious probleme: during late summer. These
dlieasos inmust bo control led to prevent pi.''aiur do follation in the fall,
thus assuring a stronger vine in dormancy and better yields the following

A long growing season, high temperatures, abundant rainfall, and high hu-
midity mIake bunch grai e disca.c very dJl'l'i.ult to control in ['lorida.
Therefore, a vigorous spray program must be started in the spring when buds
are 2-6 inches long and continued t hrougho:i)ut, the season. Fungicides should
be applied every 10-14 days until a week before harvest, and every 3-4 week
from harvest through November or until dormancy.

Since muscadines are resistant to anthracnose, the first spray can be de-
layed until Just prior to bloom. As hunch 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 followingL table. A spreader-sticker may
b included in the spray.

Amt./100 gal. Amt. per Days before1
' 'unIlc i dee per acre gal. harvest

Iv.n:,ate D 1 1/2 lb.

Dithane M-22 Special 1 1/2 lb.

'ap tan 2-4 lb.

Phaltan 2-4 lb.

Bonlate 1-1 1/2 lb.
1 ,, .

1 1/2 TBS2 7

1 1/2 TBS 7

2-4 TBS 7

2-4 TBS 7

1-1 1/2 TBS 7

''is i1 tihe recommended mt inirmum niumtrbe of days between last application
oF fung icide and hat'vo;,t.
''TB = tablespoon.

Weed Control in Florida Vineyards (.J. A. Mor'tensen)

)r(e of the secrets of succe ssful Irape g:r, wiring is an integrated program of
wooid control involving mechanic caIl tools:, tiherbicides and mulches. Weed con-
teol between vine row; is much easier t,o accomplish than that under the
treotl s itself. lerhicides are rr'oely u ::nd for weed control between rows
:' nc mowing, disk inl';, or rototil.l ing ar t morc practical and less expensive
hIlth in young vineyards; and mature virnoeya,'ryds. The discussion below con-
corns control of weeds in the vine row wlher diskinf and mowing are not

Young vineyards. Mulching with 3 inches of oak leaves or pine
II',l];; around eacti iwwly s:t gelapc vi nio hiilp, control woods arid conserve
i>i i m i ;1ture. lloel ,; o)f wood s in finall I vineyard is usual ly replaced by

herbicide spraying in vineyards one a'r, or larger. Paraquat kills all
I he ]("*i I l1'; e 12 'nv, ': i ,' I i I i)g I'..' i" i i I I aI .' A l, ra c to1 -
mounted boom with a nozzle surrounded by a cone-shaped shield to pre-
vent drift of spray in windy weather i:. effective In directing the
m1:it riu1a I o a band a l'ig etach ;;id, o' II, r 'w without getti ng on the
grape plants. Sufficient overlap of spray bands between vines in the
ow is essential to avoid leaving :. a gren ::1rip of weeds under the
trellis wires. Herbicides may need to be applied early in the morn-
ing or late in the afternoon to avoid mid-day windiness. Also, spray
when for1Ocast for showers i.s lss than 'J50. Ualapon herbicide con-
trols grassy weeds. Apply in April or May, or when the grass is green
and actively growing. Avoid spraying the grapevine foliage or on bare,
ground. roundup (Glyphosate) weed killer iv' ':e xcel lent control and
c.'n be sprayed on actively growing weed .leaves, but severe injury to
vines can result if any gets on grape leaves. In Stonev lle, 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
sprayLng. Surrflan can be applied on young vineyards as a pre-emergence
wic-d c control.

Mature vineyards ( years ( oldcr)er. Karrex (D)iuron) herbicide
i: an effective pre-emergence herbicide I' applied once a year, usually
in March. Weed growth occurrini; in Ie pow; in mid- to late summer can
bI' burned down with Pnraquat herbicide, hoed, or sprayed with Roundup.
Ioalnpon is effective on grassy weeds as Bermuda grass sod. Do not
mix )alapon with other herbicides in the ,spay tank. Karmex and Paraquat
imry be mixed where both a pre-emergence and "burn-down" of existing weeds
ire needed at once. Thorough cleaning of spray tank, hose, and nozzles
y.v draining, flushing, and clear in g with L '. (r'l'eriln a0r'e recommended Pol-
5iwingri the use of herh icides Hiundup ''.in el iminate weod growth for two
or Lthvee months, whereas weed nregrowt h occur:; within three weeks with
!'.rauat. A tank mix of' ;urf"lan and oioundiup has proved effective at
A.R.C., Monticello for pre-emer~gence and "burn-down" control.

I I. r i I. d ,2 us 1 'd f ''1 I

A\mL o I' A/,- '
! product Rates used pread. peci vacations
!ll' ;uat I qL../50 g;l . 11 n",./') ": I Woe above-gr'ound portion
4 tsp./gal. I /lt:p./':.). of weeds whenever needed
( I, 1', ) I L i mr .:; a .'/( ) r' ) .
"'I l.'poi) 5 lbs. /'0 gal 'I n,./() g', Wet laf sur ace when
0.1 Ib./gal. I/2 L' n. / l. grass is actively growing
(twice each year, 3
weeks apart).
':rm x s'iOW 3 T s./:'np'av lon r 'P 1lierd Wet surface of ground
acre evenly in a band on each
2 tsp./ral ./ side of row (once each
100 s L. 't. year, usually March).
Vines must abe 3 years old
and l 1/2 inchh(; trunk
d Larmeter.


AmL. of X-77
Product Rates Used Spreader Specifications
Surflan 75W 4 lbs./sp)rayed None requi red Safely sprayed right
(oryzalin) acres after planting2. Irrigate
after application if 1/2"
rainfall does not occur.

Houn(dup 4 lbs ./npr'ayed None rpqulired Wet weed leaves but care-
(glyphosate) acre fully avoid spraying
4 Tbs. + 2 tsp. grapevines.
per gallon

Caution: 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
3Roundup 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 l'lori:n is very limited. A one-acre
block of muscadine grapes was planted in 1974, and in 1976 was divided
into 6 blocks -- 3 microet-irrigated and 3 non-irrigated. All irriga-
I 1on equipment was dintlod by Southlrn Citrus Nurseries Cor1loration, Dundee,
Florida, who sell Microjet irrigation systems. Results in 1977 showed
a 68% increase in yield and an 83% Increaseo in weight of prunlngs (Table
0). 1977 was a relatively dry year whlch accentuated irrigation effects.
In 1978 only 19% increase in yield was obtained, but an 86% increase in
pruning 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 nonirri;ated blocks, the pruning weights were 34% higher in
the r Irgated plots.

Va'rital differences in PI' ponin t' o i irrigation were evident (Table 7).
'Welder', 'Fry', and 'Tarheel' were the mon;t responsive to irrigation
in all 3 years, whereas 'Jumbo' and 'Southland' were relatively unre-
sponsi V.

I'runling wood weights also showed varietal di lferences (Table 8), with
'Hligins', 'Regale', 'Tnrhool' and 'Doroon' showing the most increase
from irrigation and 'Carlos', 'Jumbo', and 'Dixie' showing a decrease.

Mlcrojet irrigation appearss to be superior to drip irrigation in that
either dry or liquid fertilizers may be used, whereas with drip systems
only liquid Pertilizer': can be used. It is recommended that the conduct-
In) tubes along each row ,e elevated by staVike or other support systems
to a height of 12 to 1 Inches to reduce l inie breaks and Interference of
wato r distribution.

T"ibloe f F nr'f ctsc o nill p l, i l ii i i n :i no-aR re block of

m Uc d]in ,l l-o(] )' la3,tIt in i l 1 .)
_> t -p /v i e-
Frui t yi rlds ( 1lb/v _n)
1 i I .


45. 'I
;^ lf,


Pruning wts (ib/vine)

.1 rrig.

'Y -


'I .J
TI '



I i gg

,I unb

o 7. Yield Incrons cultivars planted ri 1J974.
Pounds p)er vinoe
ivar 1977 1978 1970
lor 0.1 I I. I 7. .
12.3 2IP. 10.0(
eel 6.8 13.7 6. .
;ins 20.11 12.3 -3.
os 5.0 7.4 8.(
e 18.0 7.0 5.9
irt 7.2 8.9 2.
e 8.1 7.1 1 8
1 e 111.9 2.0 6.2
oen 10.0 11.7 9.
o 6.2 1.0 6.7
hbland 0.8 0.9 2.1

1 ration

of 12 muscadine

3 7-:71-
- 3.8

Table 8. Pruning wood weights from 12 cultivars
without lin ), olti, ii'altt i;l. ______ ___
PlounrJ;s por vine
1977 1971 1979
t1 i var 1J N 1. Fre. I I r N. I.

I i ;f': 1 l ;;

'I io i' I
I I(oon

south] and

', L.llb O
I i xi 1

8. 1
5. 4
2. 8
16. 8
10. 1

7I 3



9. )

8. I


;*' .
S. 1I


6. 3
C) 4

)9. 8
8 .

7. 1
7 .8

9. 1
6. 7
1 4.0

F. 5

with and

Irr. N.T .

10. 3
7. I
6. 4



S1979 '
M, "I I


I 0.0

1 n r.





Fertilizer N-P-K Factorial FJxperilnent (J. 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, differences were not statistically signifi-
cant for yields or weight oL' dormant prunirng 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 ft. below surface than where it was
5 or more feet deep.

Breeding grapes for Florida (J. A. Moiterinun)

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
breedi ng has begun. Efforts to transfer ;(eedl.e):s gone,: from bunch
grapes to muscadines by way of bunch-muscadine hybrids are being made.
I'9-15, a fertile bunch-muscadine hybrid being used as an intermediate
carrier of seedless genes, can be seen on the tour.

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