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
GRA I, VFIE1LD) DAY
AGRICULTURAL RESEARCH CENTER, LEESBURG
.,.I "UNIVERSITY OF FT,ORTDA, IFAS
THURSDAY, JULY 16, 1981
9:30 a.m. to Noon
The grape field day this year Is being held at the time bunch
grapes are ripe, but will include research on both bunch and
muscadine grapes. In 1982, the grape field day will be held
when the muscadine grapes are ripe (third Thursday in August),
and will include both bunch and muscadine grape research also.
Dr. Timothy Crocker, IFAS Fruit and Nut Specialist, Fruit
Crops Dept., Gainesville, will preside at the Field Day.
9:30 a.m. 10:05 a.m. Registration and bunch grape cultivar
fresh fruit taste panel (all people in attendance are in-
vited to rate varieties and breeding selections for qual-
10:05 a.m. Welcome by J. A. Mortensen, Geneticist, Leesburg.
10:10 a.m. 10:50 a.m. Discussion of grape research in pro-
Dr. D. L. Hopkins, Plant Pathologist, Leesburg
Dr. W. C. Adlerz, Entomologist, Leesburg
Dr. R. P. Bates, Food Scientist, Gainesville
Dr. J. A. Mortensen, Geneticist, Leesburg
Dr. T. E. Crocker, Horticulturist, Gainesville
10:50 a.m. Guided tour of screenhouse, mist bed, and research
vineyard. People are asked not to pick grapes in the ex-
perimental vineyard because yield data are needed from
them. Tour ends at noon.
U, RAR Y
I. A.S. U ij Firi
Leesburg ARC Research Report (WG81-2)
The Institute of Food and Agricultural Sciences is an Equal Employment Opportunity Affirmative Action Employer authorized to provide research,
educational information and other -vices only to individuals and institutions that function without regard to race, color, sex, or national origin.
Insect Control on Florida Bunch Grapes (W. C. Adlerz)
Many insects can be found on hunch grape:p in Florida. Some
can be severely damaging and control may be necessary. To
keep spraying to a minimum, growers may wish to become ac-
quainted 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
Among the most persistent and damaging insects are the grape
flea beetle, grape leafhopper, and grape root borer.
These are discussed briefly.
Grape Flea Beetle
Grapevines are damaged by adult and by larval grape flea bee-
tles. Adult beetles are dark bluish-black and about 3/16 inch
long. They are usually the first insects of the growing sea-
son to damage grapevines. Adult beetles feed on primary buds
which then cannot develop into primary canes, so crop yield is
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 upper surface
of leaves, and on developing flowers and buds reducing yields.
Since both adults and larvae are easily seen, vineyards should
be carefully monitored in the early season paying special atten-
tion first to cane and then to flower buds. Insecticides
should be applied when necessary.
G rape Leafhopper
Grape leafhoppers can be expected to infest vines each year.
Adult and immature insects feed on the undersides of leaves
causing pale feeding spots visible from above and even general
discoloration. Vine growth and sugar content of the grapes
may be 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 leafhopper adults are light colored, about 1/8" jong and
very active. Immature are very small, often difficult to see,
usually immobile, but can be provoked to activity by touching.
An application of insecticides made prior to flowering and a
second 2-4 weeks after flowering will result in good leafhopper
control if one elects preventive prayriy ng.
Grape leafhopper control exp[ertlment, 1980.
Procedure: An experiment was designed to compare Orthene 75SP
at 0.125, 0.25, 0.5, and 1.0 Ibs AI/acre and Mesurol 75WP at
1.0 lbs AI/acre. Applications were made to Lake Emerald Grape,
4 plants per plot, replicated 6 times. Insecticides were
applied once on June 17 with a Solo Junior model 410 backpack
mistblower. Evaluations were made by counting leafhoppers on
10 leaves per plot at weekly intervals after application.
Results: Orthene and Mesurol were both very effective in re-
ducing populations of the leafhopper (Table 1). Residual ef-
fectiveness of Mesurol at 1.0 pound AI/acre was sustained 1
week. Residual effectiveness of Orthene at rates of 0.125
and 0.25 pound was sustained 5 weeks and at rates of 0.5 pound
and 1.0 pound, 7 weeks. At 7 weeks, leafhopper numbers were
still very low on plants sprayed at the Orthene 1 pound rate.
Grape Root Borer
Grape root borer may be the most serious threat to grapes in
Florida, having the potential to kill both bunch and musca-
dine vines. Larvae tunnel in the roots, reducing root dia-
meters and girdling even large roots. Large larvae often 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 22 months before coming to
the surface to pupate. In Florida, the adult moths are active
and can be seen in the vineyard in daytime, mainly in October.
Adults are brown, wasplike moths with yellow markings. Females
lay eggs on a variety of plant materials or on the ground.
Newly hatched larvae tunnel through the soil to theroots.
Control methods may include injection of insecticidal fumi-
gants into the soil and spraying the ground to kill newly
hatched larvae in late September and October. Larval control
with surface applied sprays has not yet been evaluated in
Florida. Control may be difficult.
Root borers have been found in most varieties of grapevines in
Florida, Table 2.
Other insects or damage commonly seen.
Grape leaf folders, grape leaf skeletonizers, grape phylloxera,
grapevine aphids, and damage from anamola beetles are commonly
seen in vineyards.
All are considered minor pests that may not require control
efforts. Grape leafr olderr; and :;skletonizers may be especially
abundant in the late summer and fall. Skeletonizers (brightly
Table 1. Le~fr.ocers cer 10 leaves from Lake E-era:ld plants treated with insecticides on June 17 at the
ARC Leesbur; Farm.
Leafhoppers / 10 leaves
Treatment Formnuaticn AI/acre Treatment Post treatment
6/16 6/27 7/1 7/9 7/16 7/22 7/31 8/5 8/11
Orthene 75 S? 1.0 5.7 0.0 a 0.5 a 0.7 a 0.3 a 1.3 a 2.7 4.2 a 6.2 a
Orthene 75 SP 0.5 6.3 0.3 a 0.2 a 0.5 a 1.8 a 1.3 a 3.7 7.8 ab 14.7 ab
Orthene 75 SP 0.25 4.8 0.8 a 0.5 a 2.8 ab 2.0 a 2.0 a 4.2 13.2 bc 26.2 be
rthene 75 S? 0.125 6.7 0.5 a 2.3 ab 2 3.5a 5.0 13.7 tb 21.2 b
.esurol "5 1.0 5.: 0.0 a 2.7 a 3.5 bc 3.7 b 5.0 b 6.3 1.0 c 23.5 c
Untreuaed -- --- 3.5 3.0 b 12.2 t 13.5 c 15.7 c 9.2 b 7.3 19.2 c 25.7 c
Table 2. OccuIrrence ol' grI'ap' rot, b Iorers on various
,ranes in the laboratory research plant-
ing ;n11( n (,coiiin re1 l1' vineyard: cast
pupal skins at the soil surface.
Pupal skins per vine
I abo81 rt '. y I Commerclal.2
_____.97) [T-~) ._ 1980
Blue Lake 0.11
Lake Emerald 0.8
Southland 0.0 0.' 0.6
Magnolia 0.0 0.2 0.6
Thomas 0.2 0.3
Redgate 0.2 0.8
Chief 0.2 0.0
Regale 0.3 0.0
Magoon 0.5 0.2
Tarheel 0.7 0.3 1.4
Welder 0.8 0.0 2.6
Watergate 0.8 0.0
Fry 0.8 0.3 2.6
Creek 0.8 0.0
Dixie 1.2 0.3 0.4
Dearing 1.' 0.3
Jumbo 1.3 0.0 4.0
US42-12B 2.2 0.2
Cowart : 0.0
Noble 2.3 0.3
Hunt 2.3 0.6 3.4
Sugargate 3.3 0.3
Carlos 3.6 0.2 2.5
Higgins 4.0 0.0 2.7
1Average from 6 single-plant replications.
Average from 5 to 15 plants of each variety.
colored yellow and black striped larvae feeding in groups)
should not be allowed to denude vines, so they should be sprayed
If necessary. I f ['olialrge' (dippear, 'omaining foliage is
smeared with black frass, and no insects are seen, look for
anomala beetles under.vine:, or look for insects eating foliage
Insecticides For Bunch Grapes
When to spray
Bud break to flowering
(or later for beetle)
2-4 weeks after bloom
Late April through
I n e c t I c de
Methoxychlor or Leafhopper
(as above) Leafhopper
Methoxychlor Leafhoppers 2
Carbaryl (Sevin) Fruit beetles
Pre-bud or post harvest (DI-chlor emulsion) Root borer
Malathion 1.5 pints 57% enulsiriable concentrate/100 gal. water
1.5 t/gall on
Days before harvest 3
Carbaryl 2 pounds 50% carbaryl wettable powder/100 gal. water
Days before harvest 0
Methoxychlor 2 pounds 50% methoxychlor wettable powder/100 gal. water
Days before harvest 14
dichloride According to label
When this insect is a problem preventive spraying will be needed.
Grape leaf folder, leaf skeletonizer, hornworms, berry moths.
1980 Grape Fungicide Toet (I. ,. Ilopk ins)
Purpose: To compare fungicides for their effectiveness on grape
Procedure: The trial area consis:teld oI' 5 rows of "F4-36" with
20-25 plants per row. Test plot:: wor'. arranged in a randomized
block of 4 replicationsw with 3 vineo;, per plot. Treatments were
begun on April 17 and a ppl i ed every ;' weeks through the season.
Approximately ]50 gallons off spray per acre was applied.
Phaltan 50W alt.
Orthocide 50 alt.
Benlate + Manzate D
Phaltan 50W alt.
*0 = no disease, 10
DM = downy mildew,
' i 1 ..- 2 i l'
t ibs..-2 lbs.
1 Ib.+1.5 lbs.
1.5 lbs.-2 lbs.
Atnt,ihrnc. DM R Tsar'.
I 1bs.-I.5 lbs. 4.0 4.9 1.9 1.7
1 lb. 5.9 5.6 0.9 2.1
-- 6.5 7.1 3.4 5.4
= very severe disease. Anthrac.= anthracnose,
BR = black rot, and Isar. = Isariopsis.
1980 Dormant or bud-break Fungicide Test (D. L. Hopkins)
Purpose: To compare several dormant, or early growth stage,
fungicide treatments for ;anthracmiose control.
Procedure: The trial area consisted of 8 rows of "L9-11"with
24 plants per row. Liquid lime sulfur, tribasic copper sulfate,
and THAT flowable sulfur were applied to dormant vines on March
6. Benlate, Difolatan 41', and Orthocide 50 were applied on
March 24 which was about 10 days after bud-break. At both appli-
cation dates great care wa; taken to thoroughly wet all the old
wood on the vines us i.in aI)pvrox.iim.ttely 50 gallons of spray per
acre. The routine vineyard spray program was used on all treat-
ments throughout the season.
Liquid lime sulfur
Tribasic copper sulfate
Liquid lime sulfur
Rate/50 gal. canes (4/17)
5.0 pts. 2
10.0 lbs. 3
6.0 gals. 8
1.5 Ibs. 5
8.0 Ibs. 20
8.0 gals. 18
2.5 qts. 42
Disease Control of Bunch Grape in Florida (D. L. Hopkins)
Disease control is an absol ute necessity to successful bunch
grape production in l'lorida. The most severe fungal disease is
anthracnose, whi (h affectt.; both fCol.i: a) :ind fruit. There are 3
other fungal fruitl r'ot:, b l.acic r'ot, ripei rot, and bitter rot -
that must be conltlco I Id. A intzmboi'r l' I :tf'.pot disCasoe becorne
serious problems during late summer. These diseases must be con-
trolled to prevent pi'rmatlire d fol i :i. on in the fall, thus assur-
ing a stronger vine in dormancy and better yields the following
A long growing season, high temperatures, abundant rainfall, and
high humidity mal;e grap:'l, dll: :;a:; v,'t'y i c flicult to control in
Florida. Therefore, a vigorous spray program must be started in
the spring when buds are 2-6 inches long and continued throughout
the season. I.Fugicldce s;houLd be appi Led every 10-14 days until
a week before harvest, and every 3-11 weeks from harvest through
November or until dormancy.
The fungicides Manzate D, Dithane M-22 Special, Captan, Phaltan,
and Benlate are effective in controlling grape diseases in Florida.
In recent tests, Benlate and Captan have been especially effective
in controlling black rot, thus increasing marketable yields. A
spreader-sticker may be included in the spray.
Amt./100 gal Amt. per Days before
Fungicide per a cre __ gal. harvest
Manzate D 1 1/2 lb. 1 1/2 TBS2 7
Dithane M-22 Special 1 1/2 T. 1/2 TBS 7
Captan 2 1b. 2 TBS 7
Phaltan 2 Lb. TB3 7
Benlate L-I L/_ lb. 1-I 1/2 TBS 7
1l e__- I 1 i .ll 2B______7______
This is the r c( iimirl ,'ni' i :llimmllli iiIImmlI r' p or day:; betwpeIn lar1 It
application of' 'lunijci dci ( tnd h;tirvi::t.
2TBS = tablespoon.
Weed Control in Plorida Vineyards (J. A. Mortensen)
One of the secrets of successful grape growing is an integrated
program of weed control involving mechanical tools, herbicides
and mulches. Weed control between vine rows is much easier to
accomplish than that under the trellis itself. Herbicides are
rarely used for weed control between rows since disking, roto-
tilling, or mowing are more practical and less expensive both
in young vineyards and mature vineyards. The discussion below
concerns control of weeds in the vine row where disking and
mowing are not possible.
Young vineyards. Mulching with 2 to 3 inches of oak leaves
around each newly set grapevine helps control weeds and conserve
soil moisture. Hoeing of w(eedsl in small vineyards is usually
replaced by Paraquat spr)ayingV or in-aind-out rototilling, or both,
in vineyards one acre or larger. Paraquat kills all the leaf
surface it cover;n, incl I i ri': grpvi ne oliage. A tractor-
mounted boom with a no:zle surrounded by a cone-shaped shield
to prevent drift of spray in windy..weather is effective in
directing the nmatl.rial to a band along, each side of the row
without getting; on the gr ape plnLat;. ul'flicient overlap of spray
bands between vines in the row is essential to avoid leaving a
green strip of w'ed;:: idr 'l l l' l'i Ii1 : w I re l tpo'ln herrh I 'l do
controls grassy weeds. Apply in \ApvriL or May, or when the grass
is green and actively, growingr. Avoid spraying the grapevine
Collage or on b01:1t' ground. loiirndip (; I'yphosaLt) weed killer
can be sprayed on actively growLing weed leaves, but severe injury
to vines can result 1 F aiy (gts n grape leaves. Tn ,Stonoville,
Miss., a wipe-on attachment was developed for use with Roundup.
Mature vineyards (3 years o', o older). Karmex (Diuron) herbicide
is 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. Dalapon is effective on grassy weeds such
as Bermuda grass sod. Do not m:ix Dalapon with other herbicides
in the spray tank. Karmex and Paraquat may be mixed where both
a pre-emergence and "burn-down" of existing weeds are needed at
once. Thorough cleaning of spray tank, hose, and nozzles by
draining, flushing, and cleaning with detergent are recommended
following the use o h(rIr 1i ds l oundup can eliminate weed
growth for several months, whereas weed regrowth occurs within
a month with Paraquat.
Herbici des used f'or grapes
1 qt.50 gal.a
5 lbs./50 gal.
100 sq. Pt.
4 lbs. sprayo
mit.,, orf X-'(
NI o',. /[50 ga 1 .
1 0s./50 .gal.
1/2 ts!p./c 1,t .
iI o';./rn g'i:, .
1/2 tsp. /r;a.l.
Wet above-ground portion
of weeds whenever needed
(3 to 5 times a year)
Wet leaf surface when
grass is actively growing
(twice each year, 3
Wet surface of ground
evenly in a band on each
side of' row (once each
year, usually March).
Vines must be 3 yrs. old
and 1 1/2 inches trunk
Wet weed leaves but care-
fully avoid spraying
n'aution: muscadine irwpo ar' ::-ul.'l; ,j .o injury by Dalapon if the
"round is bare and het m:iari al i: t, ;n up y the vine roots.
Roundup phytotoxic !'l'crot 1,> i yr' ) !(,, nv : c o can easily occur in dr :i ted
vapor within 25 i't. 'V tlhe spe;y I I,. U;o of low pressreure and an
herbicide type no:,' i i; ,e rni ial
Irrigation of grapes (J. A. lMoirtns :n)
Bosearch on i r I .;:il, 1 it 0 ,r.-:1 ,, i n I,' d'ir i I: vwer.y 1 1 m1 i d. A
one-acre block of' miuscadi nl grape wa:.; planted in 19741, and in
1976 was divid(ed into, 6 1)blok1 o -- 3 mi crojet-l rated and 3
non-irrigated. All 1 'rlg!at ion equipment was donated by Southern
Citrus Nurseries Corporation, Dundee, Florida, who sell Microjet
1 r'r gal. lon :;ysleNi:. 21':: l l., In 1977 :;lowed a 68% increase In
yield and an 83% increase in weight of prunings (Table 3). 1977
was a relatively dry year which 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 advan-
tage of irrigation was less marked. In 1.979 there was a 12%
reduction in yield in the irrigated compared with nonirrigated
blocks, but pruning weights were 34% higher in the irrigated
Varietal differences in response to irrigation were evident
(Table 4). 'Welder', 'Fry', and 'Tarheel' were the most re-
sponsive to irrigation in all 3 years, whereas 'Jumbo' and
'Southland' we o e evelat -ve ly unti! >|'oii;.Ive.
Pruning wood woe i htt; s a-lso showed varietal differences (Table 5),
wi, th '11 Lggins' lk ':al "!'I l' I' and 'Dor'een' showing the
most increase from irri gationr, and 'Carlos', 'Jumbo', and 'Dixie'
showing a decrease.
Microjet irrigation appe;iiar' to be superior to drip irrigation
.Il that either liry or, liqluit(d f'l-. i li:,er' may be used, whereas
with drip systems only l iliil f'ol. I i .rs can be used. It is
recommended that the condlluc in ig tubes along each row be elevated
by stakes or oLtc.ie support :;y;tefm:;; to a height of 12 to 15
inches to reduce line break-; and interference of water distri-
Table 3. Effects of rnicrojet :i i la :it ion in a one-acre block
of muscadine grapes planted in 1974.
Fruit yields (Ib/vine) Pruning wts (Ib/vine)
Year Irrig. Non-Err. (%) Trrig. Non-Irr. (%)
1977 17.3 10.3 68 7.7 4.2 83
1978 35.1 2'9.5 19 8.0 4.3 86
1979 40.0 4 4 -12 7.5 5.6 34
Mean 30.7 8 7 7 6.7
Yield Increawe dur L ml ctroi U
muscadine cult var's planted in
Po iunds:; I 't viiin
1977 1.9... 1979
0. 1 I .0 17.8
12.3 12.9 10.0
6.8 1 .7 6.3
;;.o.4 12 3 -10. .
5.0 7.4 8.9
18.0 7.0 -5.9
7.2 8 2 .4
8.1 7.1 -1.8
11.9 2.6 -6.2
10.0 1.7 -9.1
6.2 1.0 -6.7
-0.8 -0.9 -2.1
Table 5. Pruning wood weillghts froir 12 inuscadine cultivars
with and without microjet irrigation.
I'ollindl per' vine
Cultivar rr. N.I. lJr. N.T.
Higgins 13.2 7.3
Regale 12. 4.5
Tarheel 8.1 .4.4
Doreen 6.7 4.1
Noble 8.9 4.5
Welder 5. 4 4.0
Cowart 4.6 3.2
Southland 2.8 1.9
Fry 7.0 2.2
Carlos 16.8 9.5
Jumbo 10.] 5.6
Dixie 10. 6.5
7. 4 8
Irr. N.I. Irr. N.I.
7.1 10.8 10.3 8.1
7.2 9.4 9.3 7.3
7.2 7.9 7.1 5.4
9.6 9.6 8.3 6.8
6.7 9.9 8.0 6.8
7.2 6.7 6.4 5.4
6.9 6.5 5.5 4.6
5.5 5.4 3.8 3.3
4.6 6.7 6.0 5.6
4.8 13.8 10.9 12.0
7.4 14.0 8.6 9.8
7.8 15.6 8.5 10.1
ert 1 ilizer N-P-K 'ac L.ori.a 1_,,xjer iorment (J. A. Mortensen)
A ratio of 3:1:2 or 3:1:1 was apparently superior to the 1:1:1
ratio of N:P:K for grapes. However, differences were not
statistically significant for yi.elds or weight of dormant
pruning wood. Under conditions; of no Irrigation, growth and
yield of Blue Lake and Norris bunch rlrapes were greater where
clay was 2.5 to 1) ft below surface than where it was 5 or more
Breeding grapes for Florida (I.. A. Mortensen)
An active breed ngr program w ith t;rapes has been continued
since 1945, wheLn Lore ton tLuove made thle fI'rst significant cross.
The emphasis was on bunch grapes until 1972, when muscadine
breeding was al.:.-o Inc uld i the pI m. New varieties com-
ing from the program are as follows: Lake Emerald (1954),
Blue Lake (1960), Norrin (1qf6), ',tovor (1968), Liberty (1976),
and Dixie (1971-, jointly wilit N.C. ;:t;ate, Univ.). A number of
both bunch and muscadine ,selection, appear promising, and best
ones should be released in the near' future. A rootstock to
replace Dog Ridge is presently being considered for release.
No seedless selections are ready yet-, ul t more emphasis on
seedless grape breeding has begun.
The State University System of Plorida offers educational pro-
grams to all people without regard to race, color, sex or na-
AN EQUAL OPPORTUNITY EMPIL)Y I~W