Group Title: Bunch grape field day.
Title: Bunch grape field day, Agricultural Research Center, Leesburg
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Title: Bunch grape field day, Agricultural Research Center, Leesburg
Series Title: Bunch grape field day, Agricultural Research Center, Leesburg
Physical Description: Serial
Language: English
Publisher: Agricultural Research and Education Center.
Publication Date: 1988
 Record Information
Bibliographic ID: UF00076046
Volume ID: VID00005
Source Institution: University of Florida
Holding Location: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: oclc - 144618183

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not reflect current scientific knowledge
or recommendations. These texts
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record of the Institute for Food and
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used only to trace the historic work of
the Institute and its staff. Current IFAS
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site maintained by the Florida
Cooperative Extension Service.

Copyright 2005, Board of Trustees, University
of Florida




SJuly 20, 1988

Central Florida
Research and Education Center-Leesburg

IFAS, University of Florida

Leesburg CFREC Research Report (LBG 88-5)
The Intitute do Food nd Agricultural Sciences is an Equal Employment Opportunity Affirmative Action Employer authorized to provide research, educational
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Central Florida Research and Education Center, Leesburg
IFAS, University of Florida

July 20, 1988

Dr. Mary C. Halbrooks, Extension Horticulturist, Viticulture


9:00 Registration and taste panel of released cultivars and
experimental selections (lunch ticket sales first-come,
first-serve -- $5.00 each)

9:45 Self-guided tour of research vineyards

10:30 Depart to Oxford Estates clubhouse (1 mile)

10:50 Welcome, Dr. Charles A. Conover, Center Director

11:00 Dr. D. L. Hopkins, Plant Pathologist, CFREC-Leesburg,
Plant Disease Research on Grapevine

11:20 Dr. C. A. Sims, Enologist, Food Science and Human
Nutrition, Gainesville,
Enology and Grape Utilization Research

11:40 Dr. D. J. Gray, Developmental Biologist, CFREC-Leesburg,
Grape Tissue Culture Research

12:00 Catered Lunch by Sonny's barbecue includes beef & pork,
BBQ beans, coleslaw, potato salad, rolls/butter and ice

(lunch tickets may only be purchased at registration!)

1:00 Dr. J. A. Mortensen, Geneticist, CFREC-Leesburg,
Bunch Grape and Muscadine Breeding Program

1:20 Dr. M. C. Halbrooks, Extension Horticulturist,
Viticulture, Fruit Crops Department,
Horticultural Research on Grapes

1:40 Dr. S. E. Webb, Entomologist, CFREC-Leesburg,
Monitoring Grape Root Borer Emergence

2:00 Close of Program

D. L. Hopkins, Plant Pathologist, CFREC-Leesburg, PLANT DISEASE

Pierce's disease of grapevine is the disease that has had
the greatest impact on grape production in Florida. It is the
reason that we cannot grow European- and American-type bunch
grapes in Florida. Hybrid bunch grapes with resistance to
Pierce's disease or muscadine grape must be grown. Several
projects address the problem of controlling this devastating
disease and others.

Screening for Resistance to Pierce's Disease
Since the only method of controlling Pierce's Disease is to
grow resistant cultivars, we are working on methods for rapidly
evaluating resistance to the disease in grape breeding lines. A
toxin produced by the Pierce's disease bacterium is being tested
as a method of screening for resistance. This could reduce the
time needed for the selection of resistant lines as potential new
grape cultivars from the 5-10 years that is currently needed to a
few weeks or months. This would decrease significantly the time
required to develop new grape cultivars for Florida.

Role of Stress in the Development of Pierce's Disease
Since plant stress has been observed to make Pierce's
disease symptoms more severe, studies were conducted to evaluate
the development of the Pierce's disease bacterium and symptoms in
relation to the stress of fruit production. The effect of growth
regulators, that either increase or decrease plant growth, on the
development of Pierce's disease was also studied. Information
gained in these studies should lead to cultural practices that
would minimize the effects of Pierce's disease. This may be most
effective on grapes such as the muscadine cultivar 'Carlos' which
is susceptible to Pierce's disease, but in many situations
continues to produce. Perhaps by reducing stresses due to
drought, to low fertility, to heavy crop load and to other
diseases, 'Carlos' and other cultivars that are only moderately
resistant to Pierce's disease could be kept free of Pierce's

Determination of Natural Hosts of the Pierce's Disease Bacterium
in Florida
In an attempt to identify wild host plants that might be the
source of the Pierce's disease bacterium for the infection of
grapevines in our vineyards, studies are being conducted to
develop a method to rapidly identify the bacterium in other
plants. While the method involves new techniques for identifying
specific DNA, called restriction fragment length polymorphism,
the use of this technique could allow us to develop very
practical methods for controlling Pierce's disease. It might
identify alternate hosts of the bacterium that should be
eliminated from the vicinity of a vineyard or it might be used to
determine a time to use insecticides to control the insect vector
of the Pierce's disease bacterium.


Control of Fungal Diseases of Grape
Because of our warm, humid summer weather, fungal diseases
are a serious problem on both bunch grapes and muscadines. A
fungicide spray program is a necessity. Studies have been
conducted on the control of anthracnose and Isariopsis leaf spot
on bunch grapes and on the control of bitter rot and ripe rot
which are serious problems on both bunch and muscadine grapes.

Disease Control in Florida Grapes
Disease control is an absolute necessity to successful bunch
grape production in Florida. The most severe fungal disease is
anthracnose, 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 in the
following year.

A long growing season, high temperatures, abundant rainfall,
and high humidity make bunch grape disease very difficult 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. 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. Spray intervals
should be shortened during rainy weather, and may be lengthened
during dry seasons.

Since muscadines are resistant to anthracnose, the first
spray can be delayed until just prior to bloom. As with bunch
grapes, fungicides should be applied every 2 weeks through
harvest. One or 2 postharvest applications are beneficial. The
fungicides recommended for grape disease control in Florida are
listed in the following table. A spreader-sticker may be
included in the spray. Please read the label for application
instructions. Remember, The Label is the Law.

Fungicide Amount per Acre

Dithane M-22 Special (80%) 1 3/4 lbs.
Phaltan (50%) 2 lbs.
Captan (50%) 2 lbs.
Benlate (50%) 1 1 1/2 lbs.

Since the activity of these fungicides against specific
diseases varies, it is advisable to use combinations of materials
in a grapevine disease control program. For example, Benlate may
be tank mixed with Captan or Dithane M-22 Special.


Charles A. Sims, Enologist, Food Science & Human Nutrition,

Research is continuing at the University of Florida in an
effort to address some of the problems and challenges of the wine
and grape industry in Florida. A brief summary of some of this
research follows.

In an effort to identify cultivars or breeding lines that
have good potential for wine production in Florida, experimental
wines have been produced from several of Dr. Mortensen's breeding
lines. Some of the breeding lines evaluated show promise as wine
grapes, although wines will have to be produced over several
seasons to make sound recommendations.

Postharvest Effects on Wine Quality
Postharvest research with Stover and Noble grapes indicates
that machine-harvested Stover grapes treated with sulfite
immediately after harvest can be held for up to 24 hr before wine
quality decreases, but non-sulfited grapes should be processed as
quickly as possible. Machine-harvested Noble grapes can be held
for up to 24 hr, even without sulfite, before wine quality
decreases. Hand-harvested Stover and Noble grapes can be held
longer, even without sulfite.

Commercial pectinase enzymes are often added to crushed
grapes to increase the amount of juice yield. However, research
indicates that a pectinase enzyme also greatly increases the
amount of sediment that settles out of Stover juice. A new
enzyme system containing cellulase gave the same or better press
yields with Stover and Dixie grapes as the standard pectinase
enzyme, but with less sediment.

Processing Parameters for Stover Wine
A processing study on Stover grapes indicates that Stover
grapes harvested at an optimum pH (3.2) and acidity (0.75%)
produced a better wine than more mature grapes that had the
acidity adjusted to optimum levels prior to fermentation. A skin
contact treatment prior to fermentation had a detrimental effect
on wine quality. Free-run juice produced a better wine than the
full press juice with very mature grapes, but the full-press
juice produced a better wine than the free-run juice with optimum
maturity grapes. Similar studies with other Florida cultivars
are also needed and are planned for the future.

Fermentation temperature, especially low temperature, is one
of the main ways to improve wine quality. As a result, Stover,
Suwannee and Dixie wines were produced at 3 temperatures (40, 50,
600F) to determine the effects of low temperature fermentation on
the quality of these wines. These wines are currently under
evaluation and further research on low temperature fermentations
is being planned.


Use of Ultrafiltration in Wine Making
Ultrafiltration is a new method of membrane filtration that
may be a useful processing tool to stabilize wines and grape
juices. A white bunch grape wine, a white muscadine wine and a
white muscadine juice were ultrafiltered through several
membranes. Ultrafiltration removed brown colors from the wines
and stabilized the color. However, the flavor of these wines was
reduced by some of the membranes. The flavor of the juice was
only slightly reduced by ultrafiltration. Research is continuing
in this area to obtain the maximum benefits of ultrafiltration
without harming the flavor.

Another possible application of ultrafiltration could be in
the production of wines without sulfites since these membranes
help stabilize the color, which is one of the main functions of
sulfites. Preliminary results show that ultrafiltration of juice
prior to fermentation may be an effective way to produce a wine
without sulfites. Research will continue to examine this
application of ultrafiltration.

D. J. Gray, Developmental Biologist, CFREC-Leesburg, GRAPE TISSUE

Tissue culture is being used to: 1) accelerate the
development of new grape cultivars, 2) provide rapid
high-efficiency propagation systems and 3) study basic plant
developmental biology. Several research programs are discussed

Embryo Rescue for Development of Seedless Cultivars
A problem confronting seedless grape breeding is that
crosses between seedless cultivars do not produce seed for
progeny testing. Therefore, in conventional breeding, flowers
from a seeded vine are fertilized with pollen from a seedless
vine. This eventually results in a seed that germinates into a
seedless vine. Although successful, this method is extremely
time consuming. Using tissue culture, it is possible to cross
seedless cultivars directly and rescue the progeny from normally
abortive seed. This method allows desirable crosses to be
accomplished and dramatically shortens cultivar development time.
Approximately 500 progeny obtained from three years of embryo
rescue are planted in the Leesburg experimental vineyard. To
date, two out of four vines that have produced fruit are
seedless. This demonstrates the promise of embryo rescue for
seedless grape development. Additional embryo-rescued vines are
recovered and evaluated each year in our efforts to produce
improved seedless cultivars.

Grape Micropropagation
Tissue culture is employed as a high efficiency rapid
propagation system for grape. Pieces of grape shoot tip tissue
are cultured on a specific medium that causes the production of
many additional shoots. Shoot numbers can be dramatically
increased over recurrent culture cycles. For plant production,
shoots are rooted in soil and grown as normal potted grapes.
Micropropagation can be used to increase all bunch grape
cultivars grown in Florida and we are conducting preliminary
research to micropropagate muscadines.

The commercial application of micropropagation is for rapid
increase of new cultivars. Typically, when a cultivar is
released by the University of Florida, there is a two-three year
lag in plant availability due to time needed for conventional
propagation. Micropropagation can be used to supply plants on

Somatic Embryogenesis
We are developing embryogenic culture systems as a pivotal
step in application of several biotechnology-related methods of
grape improvement. Plant somatic embryos develop enmass in
culture vessels and resemble the sexually-produced zygotic
embryos found in seed but differ in that they are exact
duplicates or clones of each other. Each embryo grows from a


single cell which can potentially be selected for specific traits
or modified by gene insertion. Embryos develop from such
modified cells and plants that grow from the embryos are
similarly modified. One application of this technique that we
are now pursuing is the selection of mutant cells that are
resistant to Pierce's disease. This is accomplished by
subjecting embryogenic cultures to toxin extracts. The toxin
then eliminates all but extremely rare resistant cells.
Conceivably, resistant plants could be developed from susceptible
cultivars without breeding. However, difficulties in producing
an active toxin are presently inhibiting progress in this area.
Another application of somatic embryogenesis is for germplasm
conservation. Somatic embryos can be modified to function as
"synthetic seed" with respect to efficient storage and handling
qualities. Thus, somatic embryos may allow clonal germplasm to
be efficiently conserved in seed gene banks.


J. A. Mortensen, Geneticist, CFREC-Leesburg, BUNCH GRAPE AND

Ultimate success of grape growing in Florida hinges on the
development of cultivars well suited to our climate and soils.
Early years involved testing the best available muscadine and
bunch grape cultivars for resistance to diseases and
environmental stresses occurring in vineyard cultivation. Yields
were low, and Pierce's disease (PD) caused death and degeneration
of most all the bunch grape cultivars tested and several
muscadines. Through breeding it has been possible to
dramatically improve productivity and longevity of Florida
vineyards. Four categories of grape breeding research are
currently under way at the Central Florida Research and Education
Center, Leesburg: muscadine grapes, bunch grape fruiting
cultivars, resistant rootstock cultivars, and species hybrids
between bunch and muscadine grapes.

Muscadine Grapes
Testing of cultivars and breeding selections from other
states began in 1959 at Leesburg. By 1972 it became evident that
we needed to make our own crosses between muscadines in order to
increase emphasis on resistance to PD, uniformity of ripening,
high percentage dry scar, and competitive fruit quality for fresh
use, wine, or juice. Cultivars arising from this 16-year
muscadine breeding program include Fla. CA9-48, a self-fertile
black selection suitable for fresh market, juice, wine, and
jelly. It will probably be recommended for release pending its
superior performance again in 1988. It came from a 1976 cross of
Fry x Cowart.

Other muscadines showing promise are seedlings from Triumph
crossed with Fla. AD3-42 with excellent texture and flavor. We
are working toward a seedless muscadine and hope to combine
seedlessness from bunch grapes with the excellent texture and
flavor of the Triumph seedlings.

Bunch Grape Fruiting Cultivars
Begun in 1945 by L. H. Stover, our bunch grape breeding
program has continued for 43 years. Objectives are seedless
types with edible skin, red and white wine and juice types, and
others of usefulness to the Florida growers. Resistance to PD,
anthracnose, and fruit rot are also important objectives.
Seedless x seedless crosses have been continued using tissue
culture. Selections of merit have been advanced to second test
in replicated tests on own roots and bench grafted on Tampa
rootstocks. Other bunch grape selections both seedless and
processing types, are promising, and will probably be advanced to
second test by next year. To date, the quality and appearance of
fruit collected this year from bunch grape selections was
superior to that of 1987, so we are encouraged with the advances


Resistant Rootstock Cultivars
Many fruiting cultivars of bunch grapes are improved in
yield and fruit quality by grafting on a suitable resistant
rootstock. Rootstock cultivars need to be resistant not only to
PD but also to grape root borers, nematodes, and stresses such as
drought, salinity and alkalinity of soil. Three currently
recommended rootstocks for Florida bunch grapes are Tampa, Dog
Ridge, and Lake Emerald. All 3 are resistant to PD, nematodes,
and drought, but all 3 are susceptible to grape root borer and
salinity, and Lake Emerald and Tampa are susceptible to chlorosis
due to alkaline soil (high pH). Screening tests for root borer
resistance are under way with Dr. Webb on bunch grape rootstocks.
Most promising are the Haines City x Alden seedlings 13B-8,
13B-5, and 13C-12, and CD10-46 (Dog Ridge x Fla. N6-34 male),
Blue Lake, and BD7-75 (Haines City x Ark. 1105). The
borer-resistant selections are being screened for adaptability to
bench grafting also, but results are incomplete at this time. A
Dog Ridge x Tampa cross, Fla. CD9-81 appears quite promising as a
rootstock for benchgrafting and for replanting old vineyard
sites. Since muscadines are more susceptible to damage from
grape root borer than bunch grapes, we hope to soon initiate
screening tests using species hybrids between bunch and muscadine
grapes as rootstocks for the muscadines in borer problem areas.

Species Hybrids Between Bunch and Muscadine Grapes
Traditionally, crosses between bunch grapes (2n=38) and
muscadines (2n=40) have resulted in seedlings with little or no
fruit production due to genetic imbalance (2n=39). Breakthroughs
have been discovered such as Fla. H13-17 and its offspring, Fla.
P9-15, which are heavily productive, vigorous, and long-lived
vines with lobed leaves. The following species hybrid selections
are being tested for possible release to the industry:

Summit x P9-15 selections. Three selections of promise
include Fla. DB1-41, a black, self-fertile cultivar with 9 g
berries and a flesh:seed ratio of 37. Texture and flavor are
good meriting trial for fresh market. Fla. AA12-3 is a
self-fertile, black fruited seedling with deeply lobed leaves,
vigorous, productive; 127 g clusters of 7 g berries that require
clippers for harvest, similar to bunch grapes. Fla. AA12-13 is a
black fruited, productive seedling with uniform ripening and 80%
dry scar; berries 5 to 6 g in weight; suitable for wine, juice,
and jelly.

Ga. 17-19 x P9-15 selections. Fla. AA6-53 is a
self-fertile, black, productive selection with 5.5 g berries, 63%
dry stem scar, and suitability for red wine, juice, or jelly.
Fla. AA7-10 is a bronze, root borer resistant selection that is
productive, 20% solids, 5.4 g berries, and picks with 60% dry
scar. It has good texture and very good flavor; suitable for
white wine or juice.


Mary C. Halbrooks, Extension Horticulturist, Viticulture, Fruit

Florida's young grape industry is in need of information on
almost every aspect of cultural practices of grapes.
Historically research emphasis has been given to breeding in
order to develop adapted cultivars of grape for the Florida
environment. Since 1984 several horticultural research projects
have been initiated. Objectives are to provide solutions to
current problems facing the industry and begin to develop a base
of information on the cultural requirements of Florida grapes.

Benchgrafting of Vines
Current methods of benchgraft production used by Florida
nurseries are inefficient and labor intensive with most nursery
operators achieving 50-60% success rate. In this research we
want to develop more efficient methods of benchgrafting and to
increase success rates so that nursery operators may be more
profitable. Additionally we want to determine the primary
causes of graft failure and understand what effect these methods
have on growth of grafted vines. Effects of graft method and
time of planting on vine performance in the field will be
examined in the future.

Currently we are evaluating a method of benchgrafting which
involves a heat pretreatment of rootstock cuttings to induce root
initiation prior to grafting. Grafts are grown out under
greenhouse conditions with no separate step required for
callusing. Growth of roots and shoots occurs simultaneously with
callusing and graft union formation thus higher success rates may
be achieved compared to traditional methods. The procedure is
more efficient because grafts are handled only once. Grafts of
Orlando Seedless on Tampa rootstock had 88% survivors with this
method whereas Orlando on Dog Ridge rootstock had 52% survivors.
Percentage survivors decreased for the Tampa group when the time
of heat pretreatment declined but did not change with Dog Ridge.

Management Practices to Improve Fruit Quality of Orlando Seedless
Orlando Seedless is the first seedless grape cultivar
released by IFAS. Like most seedless grapes, berry size is small
due to the absence of an endogenous source of gibberellin (a
plant growth regulator produced by seeds which causes cells to
enlarge during early stages of berry development). Standard
commercial practices for table grapes in California include
applications of gibberellic acid (a synthetic form of
gibberellin, also referred to as GA ) to increase berry size. In
this research we are evaluating different rates and times of GA3
application to determine the optimum response in berry size. An
increase of 2-3 times normal berry size was achieved in this
summer's work. GA applied at a rate of 40-80 ppm when berries
are 5-7 mm in diameter, and repeated 7-10 days later, appears to
be the best rate although data has not yet been analyzed. Other


improvements in fruit quality which may be achieved with GA3
include the elimination of gritty seed traces (which form in a
small percentage of Orlando berries) and cluster loosening (which
may be required if increased berry size results in overly compact
clusters). Seed traces have been effectively eliminated in
Orlando with bloom-time applications of GA of 10-30 ppm. No
results are yet available on a cluster loosening effect.

Other management practices which may improve fruit quality
are being evaluated as part of this project. Cluster thinning
(removal of flower clusters after fruit set) advances maturity
and increases soluble solids of fruit; berry thinning (removal of
portions of the cluster after fruit set) may improve berry size,
make cluster shape more uniform and more packable. Future
research will identify optimum trellising for table grapes.

Developmental Physiology of Florida Cultivars
The physiological process of bud development and fruit set
in Florida's unique cultivars and climatic conditions are not
well understood. Problems of non-uniform and low percentage bud
break, common to viticultural regions in the subtropics, have
largely been overcome by breeding. Some of the cultivars,
however, show these tendencies (including Lake Emerald and
Daytona) and provide good models for study of these
characteristics. Plant growth regulators such as hydrogen
cyanamide (H2CN ) induce early and uniform bud break in other
cultivars of grape grown in climates with mild winter. We are
evaluating this growth regulator and other experimental ones on
Daytona to develop a better understanding of these physiological
processes and to determine what practical application their use
may have in Florida viticulture.

Results from an experiment still in progress indicate H^CN2
induces earlier bud break (by about 7 days), increases percentage
bud break (by 50%), increases the number of fruitful shoots (by
75%) and the number of clusters (by 114%) in Daytona. Fruit set
will also be examined in this study. Future work will involve
several cultivars and will include other experimental plant
growth regulators.

Mineral Nutrition and Whole Vine Physiology
No information is available on the mineral nutrition
requirements of Florida cultivars. Growers need recommendations
on fertilizer rates for optimum fruit yields and quality and the
mineral nutrient levels which are sufficient for such production.
A project using Blanc Du Bois cultivar has been initiated to
determine effects of fertilizer rates on young vine growth and
development, fruitfulness, and mineral composition of tissue.
Other work may include a study of pruning severity in relation to
fertilizer rate.


Susan E. Webb, Entomologist, CFREC-Leesburg, MONITORING GRAPE

In 1985 and 1986, as part of a regional study, the time of
emergence of the grape root borer, Vitacea polistiformes, (GRB)
was monitored in two vineyards in North Florida, near Monticello,
and in two vineyards in Central Florida, in Leesburg and
Lakeland. The table below shows the number of male moths caught
in pheromone traps in 1985 (Adlerz and Mizell, unpublished).

Location June July August September October November

Lakeland, Leesburg 0a 0 0 92 17 1

Monticello 0 10 20 41 0 0

aNumbers are totals for six traps

In other parts of the Southeast, GRB emergence tends to
occur mostly in July and August. The rate of insect development
is closely tied to temperature, thus we would expect earlier
rather than later emergence further south. Because the situation
in Florida is so different than what was anticipated, and because
we have no information for West and South Florida, we decided to
continue and extend the survey. The information gained will help
with timing control measures; the current recommendation (one
application of Lorsban) works well only if applied when eggs are

With the help of extension specialists, county agents, and
growers, we are now monitoring eight sites throughout the state.
In addition to Lakeland and Leesburg, sticky traps baited with a
pheromone that attracts male GRB are being operated near DeFuniak
Springs and Quincy, Melrose, Fort Pierce, and in Alva and
Labelle. With information on soil temperatures and with
information from studies of GRB development being conducted at
Leesburg, eventually we should be able to predict when moths will

Pt frtfkrp tftfrt


November 1987

Dr. Russell F. Mizell, Entomologist

Suggested Control Program
General Information:
Aphids, leafhoppers, the grape flea beetle, seed chalcids, and caterpillars
including the grape leaf skeltonizer and the grape leaf folder are among the
insects that may require control measures. The addition of malathion to a
regular disease control program will keep most insect pests under control.
Recently, another caterpillar pest, the grape root borer, has been reported in
the state, and is becoming a severe pest problem.

Aphids, which attack the young shoots and leaves of grapes, are dark brown in
color and can build up to high populations quickly.
Control -- Apply malathion at 1 1/2 pints of 57% emulsifiable concentrate per
100 gallons of water. For small amounts, use 1 1/2 teaspoons of 57% malathion
emulsifiable concentrate per gallon of water. Do not apply malathion within 3
days of harvest. Diazinon is effective; use according to label directions.

Feed on the lower surface of grape leaves causing a stippled or etched
Control -- Apply a spray containing 2 pounds of either 50% Sevin or 50%
methoxychlor wettable powder per 100 gallons of water; or apply malathion at
1 1/2 pints of 57% emulsifiable concentrate per 100 gallons of water. For
small amounts, use 2 tablespoons of 50% Sevin or methoxychlor wettable powder
per gallon of water; or malathion at 1 1/2 teaspoons of 57% emulsifiable
concentrate per gallon of water. DO NOT APPLY METHOXYCHLOR WITHIN 14 DAYS OR
MALATHION WITHIN 3 DAYS OF HARVEST. There is no time limitation for use of
Sevin on grapes. Diazinon is effective; use according to label directions.

Grape Flea Beetles:
One species is dark blue, shiny, and about 3/16 inch long. They can kill grape
buds by eating out the centers. Larvae feed on the upper surface of grape
leaves. Another species is light brown with lighter stripes. The adults chew
rectangular holes in the leaves early in the season.
Control -- Apply a spray containing 2 pounds of 50% methoxychlor wettable
powder per 100 gallons of water. For small amounts, use 2 tablespoons of
methoxychlor wettable powder per gallon of water. Or use Diazinon according

V D-1

Grape Phylloxera (leaf type):
Course, raised, triangular galls on upper surface of leaves.
Control -- Use 1 pound per 100 gallons, 2-3 pounds per acre of Thiodan 50 WP
when galls begin to open. Don't need to control unless infestation is detected.

Two of the more common caterpillars are the grape leaf folder, which rolls or
folds the leaves and then feeds within, and the grape leaf skeletonizer which
skeletonizes leaves.
Control -- Apply a spray containing 2 pounds of 50% Sevin wettable powder per
100 gallons of water, or for smaller amounts, use 2 tablespoons of 50% Sevin
wettable powder per gallon of water. Or use Diazinon according to label
directions. Kryocide can be used at 6 8 lb. in 25 200 gal. of water per

Seed Chalcids:
Will infest bunch grapes that are adapted to Florida conditions including Blue
Lake, Lake Emerald, Stover and Norris. Wasps, about 1/8 inch long and not
easily seen, lay eggs in developing grape seeds in late April through May.
Development is completed within the seeds. Adults then bore through the
seeds, pulp, and skin just before grapes ripen.
SControl -- Malathion applied once a week from the last of April through May (5
applications) gave good control experimentally in a location where seed
chalcids were a problem.

Grape Root Borer:
The, larvae bore into roots, often girdling them, which reduces or destroys
vine productivity. Larvae have brown heads and can reach over an inch in
length. Adult moths are red brown, rather large and resemble a wasp. Maior
indications of .larval feeding are leaf yellowing, terminal die-back of vines
and above-ground root growth. This insect infests both muscadine and bunch
grapes but is usually more prevalent on bunch grapes.
Control is generally limited to insecticide and relies on Lorsban targeted to
the hatching larvae. Do not spray Lorsban within 30 days of harvest. Sprays
should be directed to the 15 sq. ft. area around the vine. Completely cover
the ground with an insecticide barrier. This will kill the larvae as they
attempt to enter the ground to find roots. Do not allow spray to contact
fruit or foliage.
Another method of control is to mound dirt about 1 foot deep around the vines
to prevent emergence of the adults.
The timing of sprays is being determined using pheromone traps. The adult
flight period of the borer varies across the southeastern U.S. and from north
to south Florida. In north Florida (Tallahassee area) the adults' flight
period begins about July 1 and continues into October; in the Leesburg area,
late July to mid October.

V D-2

November 1987

Pesticide Recommendations for Bunch Grape Spray Program
As the grape industry has grown, growers may prefer a generalized spray
program for pests and two are given, one for bunch grapes and one for
muscadines based on the programs used in other grape-producing states. This
generalized program may be preferred by commercial growers, whereas the
homeowner/grower might prefer attacking individual insect problems.
Time of Application Pesticide Amount/Acre Cautionary Statement
------ -----------------------------------------------------------------
New Shoot Spray Imidan 50% WP 2 Ibs About 200 gal. of water
Spray when first or per acre are needed with
shoots are one Malathion 25% WP 6 lbs dilute sprayer and appro-
inch long and or ximately 50 gal. with
continue every 7 Methoxychlor 50% WP 2-4 lbs concentrate sprayers.
days until after or PARATHION IS A VERY TOXIC
bloom. Sevin 50% WP 2-4 lbs MATERIAL AND SHOULD BE

Cover Spray
Apply first
cover spray 10
days after last
new shoot spray.
Make additional
cover sprays
every 14 days
until harvest.

Grape Root Borer

SGrape Phylloxera

Parathion 15% WP
Thiodan 50 WP
Any one of the


3 Ibs


2-3 Ibs

Same as Do not apply Imidan,
above. Parathion or Methox-
ychlor within 14
days of harvest. Do
not apply Malathion
within 3 days of
harvest. No time
limit on Sevin.
NOTE: Sevin is not
effective in aphid

4.5 pts
per 100
gal water

Thiodan 50 WP

1 lb per
100 gal;
2-3 lb
per acre

Apply 2 quarts of dilute
mixture to the soil
surface in a 15 sq ft
area around the base of
each vine. Do not apply
within 30 days of
harvest. Do not allow
spray to contact foliage
or fruit.

Apply if Pylloxera has
been a problem.

November 1987

V D-3

November 1987 V D-4
Pesticide Recommendations for Muscadine Grape Spray Program

As the grape industry has grown, growers may prefer a generalized spray
program for pests and two are given, one for bunch grapes and one for
muscadines based on the programs used in other grape-producing states. This
generalized program may be preferred by commercial growers, whereas the
homeowner/grower might prefer treating individual insect problems.
--------------------------ime of Application Pesticide Amount/Acre cautionary Statement
Time of Application .Pesticide Amount/Acre Cautionary Statement

Every 14 days from
bud break until
6 to 8 weeks
before harvest.

Every 10 to 14
days during
last 6-8 weeks
before harvest.

Grape Root Borer

Imidan 50% WP
Malathion 25% WP
Methoxychlor 50% WP
Parathion 15% WP
Sevin 50% WP
or Methomyl 90% SP

Any pesticide
from above.


2 lbs

6 lbs

2-4 lbs

3 Ibs

2-4 Ibs
1/2 lb

4.5 pts
per 100
gal water

Parathion and Metho-
myl are highly toxic
materials for use
only by licensed ap-
plicators. Methomyl
can be applied up to
14 days before harvest
with vine grapes.

Apply 2 quarts of
dilute mixture to the
soil surface in a 15
sq ft area around the
base of each vine.
Do not apply within
30 days of harvest.
Do not allow spray to
contact foliage or

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