Historic note

Group Title: Bunch grape field day and vineyard tour.
Title: Bunch grape field day and vineyard tour. 1975.
Full Citation
Permanent Link: http://ufdc.ufl.edu/UF00076043/00001
 Material Information
Title: Bunch grape field day and vineyard tour. 1975.
Series Title: Bunch grape field day and vineyard tour.
Physical Description: Serial
Language: English
Publisher: Agricultural Research Center, University of Florida
Publication Date: 1975
Spatial Coverage: North America -- United States -- Florida
 Record Information
Bibliographic ID: UF00076043
Volume ID: VID00001
Source Institution: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: oclc - 144618149

Table of Contents
    Historic note
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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

Thursday, July 17, 1975
9-11:30 AM

P"' 2i
124 976

Registration and Taste--Testing, 9-9:30.jAM,

Discussions of Current Grape Research and urOt 9>FPtLaa s;
Laurence Sistrunk, Assistant County Agent, Lake iC''aty
Extension Service, Moderator, 9:30--11:30 AM

J. M. Crall, Director, ARC Leesburg

Insect problems and their control
W. C. Adlerz, Entomologist, ARC Leesburg

Diseases of bunch grape and their control
D. L. Hopkins, Associate Plant Pathologist,
ARC Leesburg

Weed control in grapes and other cultural problems
J. A. Mortensen, Associate Geneticist, ARC Leesburg

Merchandising Florida bunch grapes as fresh fruit
L. H. Stover, Asst. Horticulturist Emeritus

Demonstration of spraying methods for disease and insect
T. E. Crocker, Asst. Fruit Crops Specialist,
University of Florida, Gainesville

Tour of vineyards and demonstrations of summer vineyard
J. A. Mortensen
W. C. Adlerz
D. L. Hopkins

Leesburg ARC Research Report WG75-2
300 copies

insect Control on Florida Bunch Grapes (W. C. Adlerz)

:-ny insects can be found on Florida bunch grapes. Some can be
severely damaging if they occur in large numbers 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.

Partial List of Florida Grape Insects

Class la Class 2a

Grape flea beetle Grapevine aphid
Grape leaf skeletonizer Sharpshooters
Seed chalcid Scale insects
Grape leafhopper. Grape leaf folder (Class 1-2)
Achemon sphinx large caterpillars
Scarab beetles
Gall insects
Twig borers
Fruit beetles, bees, and wasps

a Class 1 insects have a greater damage potential than Class 2

Seed Chalcids

Seed chalcids will affect the following bunch grapes that are
adapted to Florida growing conditions: Blue Lake, Lake Emerald,
Stover, and Norris. It appears that Blue Lake is the most
susceptible variety. No 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 1/8" long arrive at grapes in late April and continue
activity through May. Eggs are laid in the developing seed during
this period. Wasps complete their development to adult within
the seed. Adults bore out through seeds, 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.


Insecticides for grape insects

Amount per Days before Insects
Spray material gallon harvest1 controlled

Malathion 50-57% EC2 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
fruit beetles
and wasps
Malathion or Sevin
flea beetles

1 Minimum number of days between last application of the pesticide
and harvest.
2 EC = emulsifiable concentrate.
3 WP = wettable powder.
4 t = 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
following year.

A long growing season, high temperatures, abundant rainfall, and
high humidity make grape diseases 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.

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
anthracnose control.

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.

Pierces 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 Pierce's

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 i? 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


Days before

Amt./100 gal

Amt. per


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.

Mature vineyards (3 years or 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
in-and-out rototilled. Dalapon is effective on grassy weeds such
as Bermuda grass sod. Do not mix 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 of herbicides.

Herbicides used for grapes

Amt. of X-77
Product Rates used Spreader Specifications

Paraquat 1 qt./50 gal. 4 oz./50 gal. Wet above-ground portion
4 tsp./gal. 1/2 tsp./gal. of weeds whenever needed
(3 to 5 times a year)

Lalapon1 5 lbs./50 gal. 4 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)

Karmex 80W 3 Ibs./sprayed None required Wet surface of ground
(diuron) acre evenly in a band on each
2 tsp./gal./ side of row (once each
100 sq. ft. year, usually March).
Vines must be 3 yrs. old
and 1 1/2 inches trunk

1 Caution: muscadine grapes are subject to injury by Dalapon if the
ground is bare and the material is taken up by the vine roots.

Merchandising Florida Bunch Grapes as Fresh Fruit (L. H. Stover)

In a 1973 test of selling through central Florida supermarkets,
both Stover and a semi-meaty red-skinned bunch grape were success-
fully marketed at about 45 cents per pound (retail). We received
about 31 cents per pound (wholesale) for pre-packaged grapes, which
were available to local markets about 3 weeks prior to the advent
of full-ripe Thompson Seedless grapes from the southwest. No test
was made in 1974 and results of a 1975 test are incomplete.

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