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
9:15 a.m. -
10:00 a.m. Program in barn breezeway
Welcome Dr. J. M. Crall, Center Director
Introduction of Guests: Mr. Jackson Haddox, Lake County
10:05 a.m. Dr. John Sites, Dean for Research, IFAS; "The
Costs and Benefits of Agricultural Research"
10:20 a.m. Senator Curtis Peterson, Chairman, Agriculture
Committee, The Florida Senate; "The Role of the Florida
Legislature in Agricultural Research'
10:40 a.m. Discussion of grape research in progress:
Dr. W. C. Adlerz, Entomologist
Dr. D. L. Hopkins, Associate Plant Pathologist
Dr. J. A. Mortensen, Associate Geneticist
11:10 a.m. Tour of experimental vineyards. Work on both
muscadine and bunch type grapes will be shown and discussed.
Noon End of field day. Break for lunch and reconvene at
Florida Grape Growers Association air-conditioned meeting
at Community Center on Dixie Avenue in Leesburg at 1:30 p.m.
The State University System of Florida offers educational programs
to all people without regard to race, color, sex or national origin.
AN EQUAL OPPORTUNITY EMPLOYER
Leesburg ARC Research Report-WG76-2
BUNCH GRAPE FIELD DAY AND VINEYARD TOUR
AGRICULTURAL RESEARCH CENTERy'EESBURG
UNIVERSITY OFFLIORIDA. ,PFAS
Thursday ,,Jiily '15, 1976
9 AM -NOON
Dr. Timothy\Crocker, presiding '5
10:00 a.m. Registration-and grape taste panel with
Insect Control on Florida Bunch Grapes (W. C. Adlerz)
Many insects can be found on Florida bunch grapes. Some can be
severely damaging if they ccur in largo numbers and control may
be necessary. To keep spraying tco a minimum, growers may wish
to become acquainted with -nsects having the greatest damage
potential, inspect vines frequently', and spray only when necessary.
Partial List of Florida Grape Insects
Class 1a Class 2a
Grap,. flea beetle Grapevirne phid
Gratno leaf skeletonizer Snaroshoot-rs
Seed chalcid Scale insJct.
Grape leafhopper Grap. folder (Class 1-2)
Grape root borer Ache;mon sphinx large cat-rpil..lar'
ra sh oprpe rs
Scarab beetles (Anomala, Class 1-2)
Fruit booties bees, and wasps
a Class 1 insects have a greater damage potential than Class 2
Grape Flea Beetle
Damage by grape flea beetles results mostly from adult feeding
on newly emerging buds in the spring, and adult and larval
feeding in the flowers. Spray when necessary.
Grape leafhoppers breed on grarp p. -lant;s Adult and youne loaf-
hoppers feed on the uni.rsi,.: of Lc'av -' removing chlorophyll
and leaving pale feeding spots, A.ctng: soots may be so numerous
as to cause yellowed leaves and .i.af drop. Excreta from those
insects may collect on the fruit ihlch will then be spotted and
possibly covered with sooty inold. A: application of insect cide
made prior to flowering and a --seccond aerpication two weeks later
will kill many overw.i.ntering adults a-nd -educe the spraying
needed later in the year when the plants ar:e arger. To keep
plants as vigorous as possible, iga:c oaHi'hoppers should be
S ed Ch ;..;.l, ds
Seed chalcids will affect tihe folioAing bunch grapes that are
adapted to Florida growing conditions: Blue Lake, Lake Smerald,
Stover, and Norris, It e~rpe:e- ths h..! Blu Lake is the most
susceptible variety. Ho information is available on susceptibility
of SV 12309. Where experience shows that seed chalcids are
abundant, an annual preventive spray program will be necessary.
Wasps about 1/8t .long arrive at grapes ffi'ne-aN l and continue ...
activity through May... Eggs are laid in the developtngSf;_--e'd drtgt'
this period. Wasps complete their development to adult within.
the seed. Adults bore out'through..-eeds, pulp, and skin just
before grapes ripen, thereby ruining any infested grapes.
Complete crop loss is possible.
Malathion once weekly from the last of April through May (5
applications) gave good control experimentally in a location
where seed chalcids were damaging. Preventive spraying is
recommended because the wasps are hard to detect visually during
the egg laying period.
Grape Root Borer
The grape root borer is the larval form of a wasp-like moth.
Larvae tunnel into the larger roots and crown below the surface
of the soil. Vines show a general decline in vigor and may be
killed. Life history and control methods have not been worked
out in Florida. Control is usually considered difficult.
Insecticides For Grape Insects
Amount per Days before Insects
Spray material gallon harvest controlled
Malathion 50-57% EC2 1 1/2 t4 3 Malathion
Malathion 25% Wp3 4 T 3 aphids
Sevin 50% WP 2 T 0 scale insects
Sevin 80% WP 4 t 0 Sevin
Sevin 23-25% flowable 4 t 0 leafhoppers
Malathion or Sevin
1 Minimum number of days between last application of the pesticide
2 EC = emulsifiable concentrate.
3 WP = wettable powder.
4t = teaspoon, T = tablespoon.
Disease Control of Bunch Grape in Florida (D. L. Hopkins)
Disease control is an absolute necessity to successful bunch grape
production in Florida. The most severe fungal disease is an-
thracnose, which affects both foliage and fruit. There are 3
other fungal fruit rots black rot, ripe rot, and bitter rot -
that must be controlled. A number of leafspot diseases become
serious problems during late summer. These diseases must be
controlled to prevent premature defoliation in the fall, thus
assuring a stronger vine in dormancy and better yields the
A long growing season, high temperatures, abundant rainfall, and
high humidity make grape diseases very difficult to control in
Flrida. Therefore, a vigorous spray program must be started in
the spring when buds are 2-6 inches long and continued throughout
the season. Fungicides should be applied every 10-14 days until
a week before harvest, and every 3-4 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. A
winter spray of lime sulfur, 2 qts. of 26--31% solution per 100
gallons of water (1 1/4 tablespoons/gal) is suggested for
Amt./100 gal Amt. per Days before1
Fungicide per acre gal. harvest
Manzate D 1 1/2 lb. 1 1/2 TBS2 7
Dithane M-22 Special 1 1/2 lb. 1 1/2 TBS 7
Captan 2 lb. 2 TBS 0
Phaltan 2 lb. 2 TBS 0
Benlate 1-1 1/2 lb. 1-1 1/2 TBS 7
1 This is the recommended minimum number of days between last
application of fungicide and harvest.
2 TBS = tablespoon.
1976 Fungicide Test
Purpose: To compare several fungicides for the control of grape
Procedure: The trial area consists of 5 rows of 'F4-36' with
20-25 plants per row. Treatments were applied biweekly beginning
on March 18. Treatments were applied in 100 gallons of water per
acre using a Solo Mistblower Model 410. Anthracnose was rated
on a 0-10 scale.
Treatments Rate/acre Anthracnose rating (6/10)
(B) Difolatan* 2.5 pts. 0.3
(A) Benlate 1.5 lbs. 0.6
(D) Captan 2.0 lbs. 1.3
(E) DPX 110" 4.0 lbs. 1.3
(F) Dithane M-45 2.0 Ibs. 2.3
(C) Untreated 3.2
* Not registered for use on grapes.
Results 1975: Difolatan and Benlatc provided good control
of anthracnose, fruit rots, and fall leafsoots. However,
Benlate does not control downy mildew and Difolatan doesn't
control powdery mildew.
Pierce's Disease (D. L. Hopkins)
Pierce's disease is the principal factor limiting the production
of grapes in Florida. The disease was long thought to be caused
by a virus but has been shown in recent years to be caused by a
small bacterium resembling a rickettsia.
Currently there is no chemical control for Pierce's disease.
However, since the causal agent appears to be a bacterium rather
than a virus, the prospects of chemical control in the future
are somewhat brighter. We are evaluating various antibiotics,
but haven't found a suitable control as yet. The production of
grapes in Florida requires the use of varieties resistant to
Weed Control in Florida 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,
rototilling, 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 weeds in small vineyards is usually
replaced by Paraquat spraying or in-and-out rototilling, or both,
in vineyards one acre or larger. Paraquat kills all the leaf
surface it covers, including grapevine foliage. A tractor-
mounted boom with a nozzle surrounded by a cone--shaped shield
to prevent drift of spray in windy weather is effective in
directing the material to a band along each side of the row
without getting on the grape plants. Sufficient overlap of spray
bands between vines in the row is essential to avoid leaving a
green strip of weeds under the trellis wire. The in-and-out vine-
yard rototiller (Hester Plow Company, Lake City) is mounted on the
side of the tractor and operates from the power take-off. It is
very effective in controlling both broadleaf and grassy weeds in
the vine row. Dalapon herbicide controls grassy weeds. Apply in
April or May, or when the grass is green and actively growing.
Avoid spraying the grapevine foliage.
SMat.u. ,re n-ad r olr).- .Karex (Dil..urn) cerbicide
is an ffootive pre --e:ncrGonce h.:rbi.cLde i. np!led on;-c- a year,
usually in M-ar'b. W eci p:rowth occur:tln In .' ro''- in mid- to
late summer can bea burnd down with Paraquat h rbiido, hoed, or
in-and -out 'rootil. I o.p n is f'fect-ive on ssy wecds such
as Ber iiuda ICras' sod. Do not n.ix Dalacoo'n "ith other hrbicldes
in the spray iltank. Kar!;ix and Paraquat ',.y b, 2 Cd uerc both
a pre--emergenrce and burn -- down o n exi st ig nEas a- nocIded at
once. Tborough cleaning of spray tiank nos,., and nozCZes by
draining, flusbhln., and, cOle.anin with l:'-:,erg:nt are :.ecorrmended
following the use of herbicides.
I1-eticidus u ud or 2C'; 3s
US.;, Ct (:
:1 qi ,/50 ..l
k tsp./r' al.,
5 Ibs /50 ,-a'!.
/. -' ((
3 lbs /, s 'ayed
:1. : -'
2 tsp.-/ga., /
100 eq. ft.
dc eai c.ti ons
W'c:t ab;:ve-gro'und portion
of wereds whenever needed
L(3 o 5 t8 imerLs a year)
WcS l.,"af au.lf:-.ace when
Sra-n :ic etivly g rowing
(tv'ju' ..'ach year, 3
weeks s apart)
J:b s'tiface of gr'oulnd
ev enly :in a band on each
sij.de of row (once each
year, s usually March)
Vines :usc bi 3 yr:'. old
and i 1/2 inches trunk
Caution, muscadine grapes arc subject to inj : by Dalapon if
the ground is bare and t:e mat.e!ra.] i.; taken up by the vine roots.
Irriga.tion of Grap.s (J. A". Trtensen)
Research on irrigation cf grapes- in Florida has beer: needed for
some time in order to determ-ine wh;,ther the. i nmprov-ennt; in vine
growth, yield, and quality Is sufficient to justify too cost of
irrigating. Beginciin: in June i 976" 'ci n :I1o have a onG. -acre
irrigation trial on muscadiine grapes and.a half.-acrc trial on
bunch grapes The trea-mnts arc (I) icrojet irrigation plots
and (2) 'Non-irrigated chock plots. Qo data arc available: at
this time, but t-he M.icrojet syste;n will be demonstrated during
the vineyard tour. -Al i.rrgati.on equipment, Incl.udin.n the
filter, was donated by the Sou,.thorn Citrus Nurseries Corporat)ion,
Dundee, Florida, who sell Micro jet syst-rm;s,,
Ferti"tz'jzr '--P-i< FYpCtorial Experiment "J. A. Yriortensen)
A r? t. o r.r 337 4 was app~rentim-su- cii'c to 1>e 1:1:1
rat~ 7 r es'entlY y recommendca clo' 'a(s HO-lev-er,
diff. >1mPr";`~!.( wClrc r statisticallyy s1PWI) I'c_-ix KYCP y tVus or
weit -,o,-rr:ant o'urinm wood. Uider cnitions of nc;
irriraiLOn.., jrQ9,th rn(2. y-.eld of Blc La: ad Nerrs buno-h
grape zero. grcrite.r wffer(_ clay was 2.5 fto f be'!'olo s:3ace
than 'rhere, 7' 't was j o_- more feet deeT.
Markc~ 2ior cia rmnc>. Lrapes as Tves'- I-". : Stov er)
Tests of ;ia~.erng Florid,-- bunch g':apes I-Iirovgh refltvai Florida
ret~: Dutlc-.4le:,s 'er,- -onduoted in i(1i3 x.~d il:75 nmG ; being
done ;in Thi Yua 0. Ti. precIoar;:r ~*V= ls:i y 2 n tthoocL' tests
has bce.n 3to ,rer ( vit G.-'en to 4-LcxcA~ :. 5V) but lin!t ed
amotv ; t bu C nd red-skinned Eo amIPO: iLc 9ii beeC-C-1 sold.
Gra;,2 1a-1v oei n n0o1Akctec6 through o ar -e.Imt jil 2. r>'
(Par : Y Cg 2laJ *-~ri through several. I ceo .L
Ret-*A Is> > uidfom 39t ).~~3 poc rund I n
pac' 3~ ~~to~.o'a~u one pouxia. '.oa Tri'er..- ~ e
ovc or-rj. 0i f -3 'c k s US usually 2 1'Y L t jw cva IKi ity
of ;u uI Thompson Seelless graeos fvor- I zono ,,nd
Cal P .v-o' 0" 1!'ore sold to thiie s L:r-. o ai. 3- 1 nts per
pou.-r Ij1. ij--n;Cund c ~i~ OruS Thc stores; r_ cas .s tt [pt
thce ::uc:; cis offo -'ct and had good sic.u s cl 501c iThem.
Bliu iuU -n'r ru :npeamred to bc mor- 'nUIaI n Failen