Group Title: Berry/vegetable times.
Title: Berry/vegetable times. April 2002.
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 Material Information
Title: Berry/vegetable times. April 2002.
Uniform Title: Berry/vegetable times.
Physical Description: Newspaper
Creator: Gulf Coast Research and Education Center, Institute of Food and Agricultural Sciences, University of Florida
Publisher: Gulf Coast Research and Education Center, University of Florida
Gulf Coast Research and Education Center
Publication Date: April 2002
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Bibliographic ID: UF00087388
Volume ID: VID00004
Source Institution: University of Florida
Rights Management: All rights reserved by the source institution and holding location.

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. ] UNI VERSITY OF
FLORIDA
EXTENSION


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A monthly newsletter of the University of Florida Institute of Food and Agricultural Sciences, Gulf Coast Research and Education Center, and Florida Cooperative Extension Service.
Gulf Coast Research and Education Center, 13138 Lewis Gallagher Road, Dover, FL 33527 (813) 744-6630 SC512-1160 Website: http//strawberry.ifas.ufl.edu
Editors: Dan Legard (legard(&ufl.edu) & Craig Chandler .I .. ,!1 .dI, Design & Layout: Christine i 1,1.. .ii, 11. ,!1 .II i .d ..I Jack Rechcigl
April 2002


Dr. Jim Mertely promoted to Head
of Strawberry Diagnostic Lab and
Coordinator of Strawberry
Pathology/Breeding collaborative
research projects
Dan Legard

In March, Dr. Jim
Mertely was promoted to the
Head of the Diagnostic Lab
in Dover and will coordinate
the joint research projects of
the Strawberry Breeding and
Plant Pathology programs at
Dover. Jim has done an
excellent job handling the
day to day activities of the
diagnostic lab and Dr. Jim Mertely
conducting research studies
with the Plant Pathology program at Dover. This
promotion was long overdue and is a result of the
outstanding job he has done in the 3+ years he has
worked at GCREC-Dover. With the creation of this
new position, we expect that Jim will be able to
improve the services that the diagnostic lab provides
the strawberry industry. We also anticipate that Jim's
unique abilities will enhance the excellence of the
collaborative research conducted at GCREC-Dover.


End of season reminders for
managing strawberry diseases
during the summer
Dan Legard

As growers come to
the end of another
strawberry season, I
would like to remind
them about some
sound management
practices for
controlling diseases
that may Field after paraquat application
oversummer in
Florida. The best way to reduce the likelihood that


pathogens will oversummer is to kill the plants and
incorporate them into the soil as soon as they are
killed. By incorporating plant material into the soil,
its breakdown and decomposition is accelerated. As
plant materialbreaks down, the survival of pathogens
decline. For Colletotrichum spp., research we
conducted in Florida
found that the pathogens
would disappear 60 to 90
days after burial of plant
debris (For more
information see:
Oversummer Survival for
Potential Inocula of
Colletotrichum Crown Colletotrichum crown rot
Rot in Buried
Strawberry Crown at http://strawberry.ifas.ufl.
edu/soilpaperjunel2.htm). If we have a dry summer,
pathogens are likely to survive for longer periods in
buried plant material. When growers use their
strawberry beds for a second crop of vegetables or
cantaloupe, this can delay the incorporation of
strawberry plants into the soil by 60 days or more.
With such a delay it becomes important that the
growers kill the strawberry plants at the end of the
season and incorporate the plant debris as soon as the
season for the second crop is over. By effectively
managing the killing and burial of strawberry plants
at the end of the season, growers can reduce or
eliminate the risk that pathogens like Colletotrichum
will oversummer and infect new plantings of
strawberry next fall.


New Acramite 50WS Miticide
Now Available
Jim Price

Acramite 50WS bifenazate from Uniroyal
Chemical Company represents a new class of
miticide now registered for twospotted spider mite
control on strawberry. Results of experiments at
GCREC Dover and Bradenton over the past several
years indicate that this miticide will be very effective
for Florida strawberry growers to control motile
stages of the twospotted spider mite. This new
miticide can be applied at 3/4 to 1 pound of product
per acre two times during the season. There must be
a 21-day wait between applications and each crop of


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'IFAS


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fruit can have no more than one treatment applied to
it.
Acramite is safe to beneficial, carries a
"Caution" precautionary statement, requires only 12
hours restricted entry interval and only 1 day must
pass between application and harvest, qualities that
enhance the usefulness of the product in strawberry
production.
Acramite is a member of the new carbazate
chemical family and acts as a GABA (gamma-amino-
butyric acid involved in neural transmission) agonist
in insects. The nature of activity is not yet
confirmed in mites however. There is no known
cross- resistance with current miticides in strawberry.
Uniroyal Chemical Company began to
deliver the miticide to local distributors on 22 March.
Growers with late-season mite problems may
consider applying this product now.

Correction for March Berry Times:
In the article regarding pamera control, neem oil was
mentioned as a choice for control. Neem oil does not
control pameras, but other neem products, such as
Neemix Ecozin and Azatin formulations of
neem's azadirachtin can be effective.




Strawberries in Miami-Dade
County
Craig Chandler

Most strawberries in Florida are grown in
west central Florida (primarily eastern Hillsborough
County), but there are small plantings of strawberries
in other parts of the state. These plantings are
generally close to major metropolitan areas (e.g.
Miami, Orlando, and Jacksonville) so that the fruit
can be sold directly to the consumer through roadside
markets or Upick operations. Recently I made a
day-trip to Miami-Dade County and visited briefly
with two growers.
Teresa Olczyk, the UF/IFAS commercial
vegetable extension agent in Miami-Dade County,
knows of six growers of strawberries in the county,
with a combined acreage of somewhere between 10
and 20 acres. Several of these growers are quite well
known in the area for the strawberry milkshakes they
sell at their roadside stands.
Miami-Dade strawberries are planted in
October on (slightly) raised beds covered with black,
silver, or white colored plastic mulch. Growers use
either three or four-row beds. The most popular


cultivars among these growers are 'Camarosa',
'Chandler', and 'Sweet Charlie'. Fields are generally
harvested until sometime in March.


-- w-
Strawberry nurseryman David Lankford, and Univ. of
Maryland small fruit breeder Dr. Harry Swartz, standing in
front of a strawberry field at Knaus Berry Farm in
Homestead, Florida.

Growers in Miami-Dade County have to
deal with most of the same disease and pest problems
that are typical in other areas of Florida, but, in
addition, they are faced with winter temperatures and
soil pH's that are not ideal for strawberry production.
The average minimum air temperature during the
winter at Miami International Airport is 60 F (16
C), while the average minimum air temperature in the
Hillsborough County production area during the
winter is close to 50 F (10 C). Soils in the
production area of Miami-Dade County are
composed mostly of limestone, which results in soils
with a pH of 8 or above. Growers combat the
nutritional problems caused by high pH soils by
using fertigation to regularly apply essential nutrients
directly to the plant's root system.


Strawberry Varieties and Disease
Resistance
J. Mertely, D. Legard, & C. Chandler

Knowing how resistant strawberry varieties
are to plant disease is important to both researchers
and commercial growers. This season, eleven
varieties and advanced selections (cultigens) were
compared in replicated experiments at the University
of Florida Experiment Station in Dover. Ten
cultigens were from our own breeding program,
while one California variety ('Camarosa') was
included for comparison. Our objective was to
determine resistance to anthracnose fruit rot (black


Volume II


Issue 4










spot) and Botrytis fruit rot (gray mold). We have just
finished
harvesting, and
preliminary data re tu
are available for
both experiments.
As
expected,
'Camarosa' is
relatively
resistant to
Botrytis, but highly 'Camarosa'
susceptible to
anthracnose. 'Sweet Charlie' had the opposite
reaction, being highly resistant to anthracnose but
highly susceptible to Botrytis. This susceptibility to a
fungus that grows at cold room temperatures is one
reason for Sweet Charlie's short shelf life.
'Earlibrite' is similar to 'Sweet Charlie' being
susceptible to Botrytis, but moderately resistant to
anthracnose. 'Strawberry Festival' is moderately
resistant to both diseases, as is 95-256, an advanced
selection being considered for release. Selection 97-
51 was highly resistant to both diseases. Although
this selection may lack some qualities necessary for
commercial acceptance, it may be a valuable parent
in the breeding program. These experiments will be
continued next season in order to provide more
information for informed variety selection.


Watermark sensors for soil
moisture monitoring
John R Duval

Efficient use of water is becoming
increasingly important as agriculture and urban
population centers compete for the same resources.
Proper irrigation scheduling and applying proper
volumes of water for optimal crop growth is essential
for profitable crop production.
During the last 50 years, many
improvements in irrigation technology have reduced
the amount of water necessary to produce
horticultural crops. The advent of plastic mulch and
trickle irrigation has greatly decreased the amounts of
water needed to produce a crop. However, irrigation
management remains one of the most misunderstood
aspects of crop production. Over- and under-
watering can lead to reduced crop yields, mineral
nutrient problems and increased pumping costs.
When determining irrigation schedules, it is
important to take into consideration things such as
wet and dry areas and different soil types found
throughout a field. If at all possible, differing areas


should be on separate irrigation systems so that over
watering does not occur. If that is not possible,
irrigation should be scheduled based on crop water
needs on the driest part of the field.
A simple moisture sensing device is the
watermark sensor. A watermark sensor is a block of
porous material with
electrical probes
embedded in it.
When a measuring
device is attached to
the sensor, via wire
leads from the buried

sensor, a numeric
Sensor value is given
indicating soil water
tension based on the resistance of an electric current
passed through the sensor. Numerical data given by
this sensor indicate soil water tension or put simply
how much force
(measured in
centibars) is needed
by the plant to remove
moisture from the
soil. Therefore, the
lower the number, the
wetter the soil. For
strawberries it is Reader
recommended that
this value never
exceed 10-12 (centibars). These sensors can be
buried at any depth, only limited by the length of the
wire lead to the soil surface. Advantages of resistive
sensors are low cost, high level of precision when
soil salt concentration is low, do not require routine
maintenance like tensiometers, are not easily
damaged by equipment or workers once placed in the
field, and function in the entire range of soil
moisture. The main disadvantage of water sensors is
the in-ground sensors have a limited life and must be
replaced after one or two seasons.



Center Update
Christine Manley

Watch for a new look to our website -
http://strawberry.ifas.ufl.edu. We will be working on
redesigning the home page as well as other main
pages throughout the site to improve the way that we
provide information. We will also be working to
provide our website visitors with easier navigation to
get them the information they need least amount of
"clicks".


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Issue 4










Dan Legard will be traveling on business to Europe in April to visit with strawberry growers and
researchers in Southern Spain and give a seminar on Botrytis fruit rot. Dan will also be presenting a poster at the 6th
European Conference on Fungal Genetics in Italy and presenting a seminar for Syngenta in Switzerland. While in
Europe, Dan will be working with other researchers to develop collaborative projects to benefit the Florida
strawberry industry. The majority of Spain's strawberry exports go to markets in Germany, France and Italy. Fresh
strawberries are also exported to Switzerland. The most important market for Italian strawberries is Germany, which
imports almost two thirds of the total Italian fresh exports, followed by Austria, Switzerland, and other northern
European countries. The trip should provide some valuable information for Dr. Legard's program.
We were proud to host several groups this past month including visitors from the Danish Agricultural
Advisory Centre, Korea and Louisiana State University. However, one of our favorites was a group of 27 2nd and 3rd
graders from St. Clements School in Plant City. The group consisted of children from local strawberry growing
families as well as migrant workers, so they already had an appreciation of some of the aspects of the strawberry
industry. It was Sister Denise LaRock's goal to expose them to the other career fields involved in the strawberry
industry and agriculture in general, and that is where our research center came in to help. The group was very
enthusiastic as they viewed through microscopes and helped themselves to a basket of berries to take home. We
welcome all types of groups to tour our facility, but we do ask that tour groups notify us early enough to allow for
proper planning. For information call (813) 744-6630 X60, or e-mail cmanlev(tufl.edu.
















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Gulf Coast Research and Education Center
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Dover, FL 33527




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