Title: Berry/vegetable times
Full Citation
Permanent Link: http://ufdc.ufl.edu/UF00087388/00064
 Material Information
Title: Berry/vegetable times
Physical Description: Serial
Language: English
Creator: Gulf Coast Research and Education Center, Institute of Food and Agricultural Sciences
Publisher: Gulf Coast Research and Education Center
Place of Publication: Gainesville, Fla.
Publication Date: December 2009
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Bibliographic ID: UF00087388
Volume ID: VID00064
Source Institution: University of Florida
Holding Location: University of Florida
Rights Management: All rights reserved by the source institution and holding location.


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SBerry/Vegetable Times

December 2009

Calendar of Events

Jan. 12, 2010 Pesticide License
Testing. Hillsborough County
Extension Office, Seffner. 9 am.
For more information call Dave
Palmer at 813-744-5519 ext. 107.

Jan. 22-23, 2010 Agritunity,
Sumter County Fairgrounds. For
more information go to http://

Feb. 17, 2010 2010 Strawberry
Field Tour and Education Program,
GCREC. For updates go to http://

June 6-8, 2010 Florida State
Horticultural Society Annual
Meeting, Plantation Inn, Crystal
River, Fl. For more information
visit: http://fshs.org.

July 31 and Aug. 1, 2010 Florida
Small Farms and Alternative
Enterprises, Osceola Heritage Park
Conference Center, Kissimmee. For
more information visit: http://

A University of Florida/IFAS and Florida
Cooperative Extension Service
Hillsborough County, 5339 CR 579
Seffner, FL 33584 (813) 744-5519
Joe Pergola, County Extension Director
Alicia Whidden, Editor
Gulf Coast Research & Education Center
14625 County Road 672,
Wimauma, FL 33598 (813) 634-0000
Jack Rechcigl, Center Director
Christine Cooley, Layout and Design
James F. Price, Co-Editor

Fromv Yowur A gevt
Changes and Loose Ends to Tie Up for 2009

Change is inevitable even though we usually resist it
for as long as we can. This goes for this newsletter too. Due
to UF budget issues we can no longer send out by bulk mail a
paper copy. This is our first e-mail only version. Thank you
to those that were receiving the paper copy that contacted us
and gave an e-mail address so that you could continue to
receive the Berry/Vegetable Times and not miss an issue. If
you know of someone that would like to receive the
newsletter have them get in touch with me and we will get
their e-mail address on our list.
This brings up another issue of getting in touch with
you between newsletter issues which is another change we

(Continued on page 2)

Breeding Update: Progress in Tissue Culture
Vance M. Whitaker, Assistant Professor of Horticulture

The Florida Strawberry Growers Association is
currently funding a tissue culture specialist for the UF
strawberry breeding program. We are grateful for this
investment, which has since allowed us to establish a
productive tissue culture
In early 2008,
Catalina Moyer became our
tissue culture specialist after
graduating with a Masters of
Science degree in plant
pathology under the direction
of Dr. Natalia Peres. The
main purpose of her work is
to promote faster release of virus and disease-free material of
(Continued on page 2)

IFAS is an Equal Employment Opportunty-Affirmative Action Employer authorized to provide research, educational formation and other services only to individuals and stitutions that
function without regard to race, color, sex, age, handicap, or national ongm U S Department ofAgriculture, Cooperative Extension Service, Umversity of Flonda, IFAS, Florida A & M
Umnversity Cooperative Extension Program, and Boards of the County Commissioners Cooperating

(Continued from page 1)
need to make for the coming year.
Occasionally we have meetings or important
issues that come up in a short timeframe and
I need to get the word out to everyone. I feel
this is an area we have not worried about in
the past but is becoming very important.
For a few of you I have a fax number but for
most I have no quick way to get information
to you. We need to develop a quick and
reliable way that I can get the word out to
you when we can not wait for the next
edition of the newsletter. It has been
mentioned that a text message to your phone
would be a fast way to get the word out. I
would like to know what you think. Would
you prefer to receive a fax, a text message on
your phone or an e-mail? Please get in touch
with me and let me know which way works
for you and also give me the phone number
( all ten digits) and the carrier service you
use, a fax number or e-mail address.
As far as loose ends to take care of,
be sure that as you hire new workers through
the season that you always give them WPS
training before the sixth day of work and that
if you do not give them the training before
they start in the field that you give them
verbally some information on where and how
they may contact pesticides and how to
prevent that and where the decontamination
site is. Also be sure that you keep current
your pesticide spray records at the central
posting site. Be sure all posters are easy to
read and not faded. Part ofWPS training is
instructing workers on hand washing but that
is also extremely important for food safety.
It would be a good idea to regular remind
workers about proper hand washing.
Emphasizing this and documenting it could
go into your third party audit paperwork as
well as in WPS training records.
If you would like to keep track of the
weather predictions, chilling hour
accumulation, monthly climate summaries,
the Strawberry Disease Forecasting Tool,

and other interesting weather information go to
I hope everyone has a great holiday
season and a very profitable New Year!!!

Alicia Whkiddev,
Hillsborough County Extension Service
813-744-5519 ext. 134
awhidden( ufl.edu

(Continued from page 1)
advanced strawberry selections. As soon as a
selection shows promise in the first replicated
trial, she isolates meristems and places them in
tissue culture. After the plantlets have grown
sufficiently, ELISA virus testing is performed
to ensure cleanliness of the stock. The clean
cultures are then sent to our collaborator Becky
Hughes at the University of Guelph, Ontario.
Becky is in a strawberry free area with a cool
climate, which allows her to produce clean and
vigorous plug plants. The plug plants are then
available to foundation nurseries.
Only a few advanced selections are
retained throughout the whole evaluation
process. However, for the advanced selections
that become new cultivars, performing tissue
culture at an early stage hastens the cultivar
release process as much as 2 years compared to
previous methods. Another benefit to this
approach is that we will have virus-free
material of advanced selections to test in the
field prior to release.
To date, Catalina has placed 25
advanced selections and 3 cultivars in tissue
culture and has tested for major viruses. For
some selections she has performed heat
treatment to eliminate virus infections. Our
most promising new selection, 05-107, has
been tissue cultured and tested to detect viruses
and will be sent to Becky Hughes this winter.
Catalina will continue to tissue culture
advanced selections identified in this season's
(Continued on page 3)

(Continuedfrom page 2)
trials. Other important functions of her job
are to process permits for shipping plant
material, to fingerprint cultivars using DNA
techniques, and to assist with planting,
harvesting, and grading fruit during the
busiest weeks of production.
Our current goal is to reach new
levels of efficiency. Catalina will be
investigating ways to reduce contamination
in the cultures. She is also manipulating
hormone levels and other factors to increase
the percentage of meristems that produce
viable plantlets. This season Catalina will
conduct a survey of strawberry necrotic
shock virus (formerly tobacco streak virus)
in growers' fields and at the GCREC. This
research was prompted by the recent
discovery of SNSV infected 'Florida
Radiance' plants at a foundation nursery.
The study will seek to determine the
incidence of this virus among several
varieties grown in Florida and whether
infection is initiated in the nursery and/or
fruiting fields.
The work performed by Catalina is
vital to success of the Florida strawberry
industry. We are fortunate to have her
involved and we anticipate more good things
to come!

Rimon Insecticide
for Sap Beetles
Expected again in
James F. Price, Associate
Professor of Entomology, GCREC

Rimon 0.83EC novaluron was
available to strawberry farmers during 2009
production season through an EPA time-
limited exemption to control sap beetles.
Rimon proved to be very useful in
controlling sap beetle larvae on strawberry

farms during its first commercial use last
That exemption expires in December
2009. However, a second petition was
submitted this fall through the continued
cooperation of Florida Fruit and Vegetable
Association, Florida Strawberry Growers
Association, Chemtura Corp., and the
University of Florida. The petition has
successfully passed the review of Florida
Department of Agriculture and Consumer
Services in Tallahassee and has been sent to
the US Environmental Protection Agency for
evaluation and approval.
There seem to be no red flags relative
to the approval of Rimon once again. We
expect the material to be permitted and
available for managing the 2010 sap beetle
threat. However, strawberry growers must
remain in contact with county extension offices
and the pesticide industry to know when the
approvals have been finalized.

Spotted Wing Drosophila Update
James F. Price, Associate Professor and Curtis A. Nagle,
Biological Scientist, GCREC

Florida Department of Agriculture and
Consumer Services fruit fly trappers continue
to discover low densities of spotted wing
drosophila in northeast Hillsborough County.
However no new discoveries have been made
outside of that general area.
Experiences in Japan and California
suggest that the cool weather we expect and
the presence of sweet, ripe, thin-skinned
strawberries now in fields will be factors in an
expansion of this insect's range soon. Growers
must remain aware of the spotted wing
drosophila and be prepared to protect their
On Page 4 is a list of insecticides
available to Florida strawberry growers to
control drosophila flies. Other management
(Continued on page 4)

(Continued from page 3)
considerations exist and are enumerated along with important scouting, identification,
ecological, etc. information, in the September 2009 issue of this newsletter http://
It would be wise for pest managers to review that article as the period of expected threat in
strawberry crops approaches.

Table 1. Insecticides available in Florida for management of Drosophila spp. flies on

Active Trade Name REI PHI2 Mode of Action
Ingredient Code3
Diazinon Diazinon 24 hours 5 days 1B
Malathion Malathion 12 hours 3 days 1B
Pyrethrins Pyganic 12 hours 0 days 3A
Pyrethrins / Pyrenone 12 hours 0 days 3A / no code

'Re-entry interval that must elapse between application of the indicated insecticide and entry of any persons into
the treated area.
2Pre-harvest interval that must elapse between the application of indicated insecticide and harvest of the crop.
3For management of spotted wing drosophila (SWD) resistance to insecticides, growers should use products from
one mode of action group during the period of one SWD lifecycle then rotate to another mode of action for a
similar period.

CSI: Plant City
Asha M. Brunings, Horticulture Grad
Assistant and Kevin M. Folta,
Associate Professor of Horticulture,

It is December. The strawberry
plants are now firmly in place and planning
for a productive winter production season.
The cultivars planted in Florida are chosen
for their familiar qualities. We know from
experience when they will flower, how much
they will produce, and when harvest can be
anticipated. Now, imagine the nightmare of
looking out into a field of strawberry plants
only to find that they are not flowering on
time. What if they never flower at all?
Situations like this have been anecdotally
reported, representing cases where the

cultivar planted was not the one intended. The
potential for mix-ups between these very
similar-looking plants is always a concern,
albeit a minor one. While it is unlikely to
happen, if it happens in your field or
greenhouse it is no small matter.
The strawberry plants for the season are
produced by vegetative propagation of
daughter plants from runners. Stray runners
can travel for meters, taking root in
neighboring pots or field rows. Tremendous
efforts ensure that such events do not occur,
but it is always possible, and not easy to detect.
In addition, human error can lead to mis-
labeling of cultivars. Individual cultivars may
also appear different depending on the climate,
geography, and nutrition status. As a result it is
often impossible to faithfully tell different
strawberry cultivars apart, especially when the

plants are still young. Can we turn to the
methods of modern forensic science to
provide a 100% accurate means to identify
strawberry cultivars?
Fingerprints provide a tool to tell two
people apart with great confidence. Recent
technologies permit incontrovertible
identification of individuals based on
differences in DNA. These DNA
"fingerprints" allow forensic researchers to
identify an individual with a certainty
approaching one in ten billion. UF-IFAS
researchers have adopted the same
technology to analyze popular Florida
strawberry cultivars, providing a new set of
tools to verify their authenticity.
The IFAS Dean for Research Office has
sponsored an effort to fingerprint major
Florida strawberry genotypes. The work was
performed by Drs. Asha Brunings and Kevin
Folta (UF-Gainesville) and Dr. Natalia Peres
and Catalina Moyer at the GCREC. What
they devised is reminiscent of an episode of
CSI on television. The scene is a familiar
one. The lab technician looks at a
transparent sheet with a series a cryptic black
lines on it and declares: "This is from the
blood sample at the scene of the crime".
Then the tech places an identical looking
sheet next to it and says: "This is from your
prime suspect-- A perfect match." The same
kind of technology can now be extended to
strawberry plants.
An example is shown in the
accompanying figure, which shows part of a
DNA fingerprint from three familiar Florida
cultivars: Earlibrite, Strawberry Festival, and
Sweet Charlie. In this process discrete
regions of DNA are amplified producing
millions of DNA fragments. The fragments
sort into 4-10 unique sizes that vary between
cultivars. The different sizes can be detected
and displayed graphically, as in the figure.
Each cultivar produces different sizes of
DNA fragments (represented as horizontal
lines in the figure). The combined pattern

formed by the lines constitutes the DNA
fingerprint. Since commercially available

( -'

*7 -- -


8 -

Earlibrite Strawberry Festival Sweet Charlie
Figure 1. A simple fingerprint pattern for 3 Florida
strawberry cultivars. Each horizontal line represents a
different DNA fragment amplified from the cultivar
shown. The different patterns for each cultivar make it
easy to tell the cultivars apart.

strawberries are vegetatively propagated, the
fingerprint pattern is stable for every cultivar.
What makes this technique very powerful
is that there are many independent ways to
generate the set of DNA fragments that make
up the fingerprint. The intricate snowflake-
like pattern obtained by using multiple
fingerprints allows the technician to easily
discern different cultivars from each other with
great certainty. The commercial strawberry
has a very complex genome, so there is
considerable variation from one cultivar to the
next. This methodology therefore makes it
easy to distinguish between a parent and its
offspring, or even siblings and other closely
related cultivars. Although the method requires

certain equipment and expertise, it is
relatively quick and inexpensive, especially
when compared to the potential losses in the
case of mis-represented cultivars. The pattern
of any unknown or questionable strawberry
plant can be compared to the known patterns
of cultivars to pinpoint its identity.
In this way the same tools that can
distinguish a criminal from an innocent
suspect in a court of law can be used to
identify one cultivar from another with great
confidence. Also, the DNA fingerprint does
not change with seasons or plant size, so
where physical descriptors break down,
DNA-based identifiers remain robust. These
valuable new tools are now in use by the
University of Florida strawberry team and
can be used to validate the identity of
cultivars relevant to the Florida strawberry
industry. These DNA-based identifiers also
can verify crosses in the breeding program,
facilitate future breeding strategies, and even
help answer questions of cultivar

2009 Florida Ag Expo Recap
This past October Gulf Coast
Research and Education Center held the 4th
Florida Ag Expo in Balm and welcomed over
800 participants to take part in 18 different
educational sessions and field tours. More
than 40 vendors were available to share
updated information on new products and
equipment for growers. A special premium-
content sponsorship provided by DuPont will
provide extended coverage of the Florida Ag
Expo for the next six months in Florida
Grower magazine. Each month the magazine
will feature an in-depth article on one of the
educational presentations. In addition, video
presentations are of the sessions are available
at FloridaGrower.net. Watch for upcoming
information and the date of the 2010 Expo.


Results of Cantaloupe Powdery
Mildew Trials
Spring 2009
Gary E. Vallad, Assistant Professor of Plant Pathology
Gulf Coast REC

In the spring of 2009, two cantaloupe
trials were established with the goal of
evaluating various products for the
management of powdery mildew, caused by
Sphaerothecafuliginea and Erysiphe
cichoracearum, a disease favored by the
cooler, dryer conditions common during the
spring. The first trial was established on
March 6th to evaluate the integrated use of
biopesticides with conventional fungicides
for powdery mildew management. While the
second trial, established March 25th, was
designed to evaluate conventional fungicides
Trials were conducted at the
University of Florida's Gulf Coast Research
and Education Center in Balm, FL, double-
cropped on beds previously used for
strawberry production. Plots consisted of 8
ft bed sections along 300 ft, raised beds with
4 ft center-to-center bed spacing. Beds were
covered with black virtually impermeable
mulch and irrigated with a drip system.
Seeds of the cantaloupe cultivar Hale's Best
were directly seeded at 30" spacing along
beds skipping a 6 ft section between plots
and every third bed as a buffer. Fungicide
treatments were applied to the first trial on 9-
Apr, 16-Apr, 23-Apr, 30-Apr, 7-May, 14-
May, and 2-Jun; and to the second trial on 28
-Apr, 5-May, 12-May, and 1-Jun using a CO2
back pack sprayer calibrated to deliver 40 to
100 gal/A at 40 psi. In both trials, a non-
treated control was included to measure
disease pressure and arranged with the other
treatments in a randomized complete block
design with each treatment repeated 4 times.
Treatments were applied prior to the
establishment of powdery mildew. Plots
were monitored regularly for powdery

mildew, and rated 13 May and 28 May in the
first trial and 14 May and 28 May in the
second trial after disease reached acceptable
levels across trials. Alternating applications of
the downy mildew specific products Previcur
Flex (1.2 pt/A) and Curzate 60DF (3.2 oz/A)
were used to minimize the impact of downy
mildew, which was critical when conducive
conditions occurred in the latter half of May.
Marketable yield was assessed from two
separate harvests of plots on 28 May and 3
June in the first trial. Whereas, conditions
were so favorable for downy mildew in the
latter half of May, the second trial was
terminated prematurely with only a single
harvest of all fruit on 9 June to avoid
Environmental conditions during the
beginning of trials were unusually dry. Only
1.23 and 1.34 inches of rain were recorded for
the months of March and April, while 10.86
inches was recorded for the month of May.
Symptoms of powdery mildew were first
observed in control plots on 30-Apr (trial 1)
and 5-May (trial 2). Due to the susceptible
nature of the cultivar, disease developed
rapidly, but a bit later than expected.

Results of Trial 1
The severity of powdery mildew on 13 May,
78 days after planting (DAP), ranged from 0 to
62.5% among plots. By 28 May, 93 DAP,
disease severity values increased, ranging from
18.5 to 95.5% among plots. Significant
differences were detected among treatments on
both dates (Table 1).
Based on disease severity on 28 May,
treatments fell into 3 groups. With weekly
applications of HMO 736, Companion,
Actinovate, BU EXP 1216 (both S & C
formulations), and Regalia forming the first
group with final disease severity values
ranging from 67 to 86%. Biweekly
applications of Procure (the standard
fungicide) alone, weekly applications of KFD
61-04 (2.3 lb rate) alone, Actinovate alternated

with Procure, and both BU EXP 1216
formulations alternated with Procure made
up the second group with final disease
severity ranging from 44 to 56% on 28-May.
The final group was composed of Regalia,
Companion, and HMO 736 rotated with
Procure, and weekly applications of the
remaining KFD experimental formulations
(70-01 at 2.5 and 5 lb rates & 61-04 at the
4.6 lb rate) with final disease severity
ranging from 23 to 38% on 28-May. The
effectiveness of all biopesticides was
improved by alternating with Procure. More
importantly, alternating applications of
Regalia, Companion, and HMO 736
improved the activity of Procure alone based
on the final disease severity rating on 28-
Total number of marketable fruit and
total weight was collected for the trial (Table
1). Significant differences were detected for
both parameters on the second harvest, 3-
Jun. When data from both harvest dates
were combined, only differences in the total
number of marketable fruit were significant,
differences in average fruit weight were not
significant either (Table 2). The KFD
experimental compounds exhibited the best
overall disease control, but this did not
always translate into improved yields;
probably due to the minor-moderate levels of
phytotoxicity observed in the field.
However, the low rates of KFD 61-04 and
KFD 70-01 gave exceptional yields and
disease control. Otherwise, Companion
alternated with Procure yielded the most fruit
per plot among the biopesticide treatments,
better statistically than Companion alone but
not Procure alone. All the biopesticides
typically yielded better in regards to the fresh
weight and number of fruit when alternated
with Procure, but this trend was usually not

Results of Trial 2
The severity of powdery mildew on 14 May,
51 DAP, ranged from 0 and 18.0% across
plots. By 28 May, 65 DAP, disease severity
values increased, ranging from 9.0 and 98.5%
across plots. Significant differences were
detected among treatments on both dates
(Table 2).
Based on disease severity on 28 May,
all treatments significantly reduced the severity
of powdery mildew relative to the non-treated
control (Table 2). Treatments fell essentially
into 3 groups of efficacy, with treatments, 2,
5, and 10 conferring the best control.
Treatments 3, 4 and 11 gave intermediate
control, and treatments 6, 7, 8, and 9 gave the
lowest levels of control. In general, spray
programs that included Quintec (quinoxyfen)
typically gave the best level of powdery
mildew control. While all the standard
treatments conferred significant protection
against powdery mildew, the difference in
efficacy between the two Rally-Quintec
treatments (Trts 3 and 11) was surprising, and
probably reflects the varying levels of disease
throughout the trial than a true rate effect. The
plant defense elicitor, Actigard (Trt 8), did not
improve the level of disease control over
Bravo Weather Stik alone (Trt 6)
Total number of marketable fruit and
total weight was collected for the trial (Table
2). Significant differences were detected for
both parameters. Average fruit weight was
calculated from total fruit number and total
weight, but differences were not significant
(Table 1). All treatments, except 6, 7 & 8
statistically out yielded the untreated control
based on weight. Treatments 3, 5 and 9
yielded the highest number and total weight of
marketable fruit in the trial (Table 1).
Treatments 9 and 10 with EXPT 1 exhibited
some minor phytotoxicity (a mild chlorosis)
that was more prevalent at the beginning of the
trial, but did not appear to impact plant
production based on yields.

(Tables 1 and 2 on Pages 8 and 9.)

Table 1. FIELD TRIAL 1: Effect of fungicides and biopesticides on cantaloupe yields
and the severity of powdery mildew.
Marketable fruit yields Disease Severityz
Treatment, rate/A Total no. 3-Jun wt. Total wt. Avg. size
(application)x (no./trt) (lbs/trt) (lbs/trt) (lbs/fruit) 13-May 28-May
Non-treated Control 10 cY 11.6 e 30.1 3.1 56.3 c 93.3 g
Procure, 8 oz (2,4,6) 17 abc 25.6 a-e 49.3 3.2 1.5 a 56.3 d
Regalia, 1% (v/v) (1-7) 14 bc 18.5 b-e 40.9 2.9 3.0 a 86.3 fg
Actinovate, 3 oz (1-7) 12 be 17.6 c-e 36.5 3.1 5.6 a 81.5 fg
HMO 736, 14 oz (1-7) 10c 16.4 de 29.8 3.1 23.3 b 72.0 ef
Companion, 32 floz (1-7) 14bc 20.0 b-e 40.8 3.0 16.1 b 67.3 e
Regalia, 1% (v/v) (1,3,5,7);
Procure, 8 oz (2,4,6) 18 abc 32.7 ab 51.4 3.0 1.1 a 37.5 be
Actinovate, 3 oz (1,3,5,7);
Procure, 8 oz (2,4,6) 14bc 17.8 c-e 41.4 3.3 2.3 a 50.0 cd
HMO 736, 14 oz (1,3,5,7);
Procure, 8 oz (2,4,6) 17 abc 30.2 a-d 48.8 2.9 1.5 a 32.8 ab
Companion, 32 floz (1,3,5,7);
Procure, 8 oz (2,4,6) 20 ab 29.2 a-d 55.8 2.8 1.1 a 37.5 be
BU EXP 1216S, 3 lb (1-7) 13 bc 17.0 c-e 39.0 3.0 6.0 a 76.8 e-g
BU EXP 1216c, 3 lb (1-7) 15 abc 24.6 a-e 45.0 3.1 2.3 a 79.1 fg
BU EXP 1216S, 3 lb (1,3,5,7);
Procure, 8 oz (2,4,6) 18 abc 25.6 a-e 48.8 2.9 0.8 a 56.3 d
BU EXP 1216c, 3 lb (1,3,5,7);
Procure, 8 oz (2,4,6) 19 ab 30.9 a-c 54.9 2.7 1.1 a 43.8 b-d
KFD 61-04, 2.3 lb (1-7) 23 a 35.8 a 54.3 2.4 1.5 a 56.3 d
KFD 61-04, 4.6 lb (1-7) 17 abc 32.9 ab 47.3 2.8 1.5 a 28.0 ab
KFD 70-01, 2.5 lb (1-7) 20 ab 38.2 a 56.2 2.9 1.5 a 32.8 ab
KFD 70-01, 5.0 lb (1-7) 13 be 25.2 a-e 38.8 2.9 1.5 a 23.3 a
P>F 0.0435 0.0509 0.1414 0.6553 < 0.0001 < 0.0001
x Treatments (TRT) were applied 9-Apr, 16-Apr, 23-Apr, 30-Apr, 7-May, 14-May, and 2-Jun corresponding with
applications 1 to 7, using a backpack sprayer calibrated initially for 40, 60 and then 100 gallons per acre after 30-
Apr. Listed treatment rates are on a per acre basis unless noted otherwise. Seeds were sown 6-Mar.
Y Values followed by the same letter are not statistically significant (P = 0.05).
z The severity of powdery mildew was assessed as the percentage of canopy affected. The Horsfall-Barratt scale
was used for all ratings, but values were converted to mid-percentages prior to statistical analyses.

Muskmelon (Cucumis melo) is a species of melon that
has been developed into many cultivated varieties.
These include different netted cultivars such as
cantaloupe, persian melon and santa claus or christmas
melon. The large number of cultivars in this species
approaches that found in wild cabbage, though
morphological variation is not as extensive. It is an
accessory fruit of a type that botanists call an epigynous
berry. Muskmelon is native to northwestern India, where
it spread to China and Europe via the Persian Empire.

Table 2. FIELD TRIAL 2: Effect of fungicides on the severity of powdery mildew and
cantaloupe yields.
Disease Severity" Marketable fruit yields
TRT Treatment, rate/acre Weight Fruit size
(application)x 14-May 28-May No. Fruit (Ibs) (lbs)
1 Leml7 SC, 16 floz (1-4) 1.1 aY 16.1 a 15 ab 37.5 ab 2.5
2 Leml7 SC, 16 floz (1,3); Quintec, Oa 16.1 a 15 ab 39.7 a 2.8
4 floz (2,4)
3 Rally 40W, 5 oz (1,3); Leml7 0a 50.0 c 18a 44.4 a 2.5
SC, 16 floz (2,4)
4 Leml7 SC, 16 floz (1-4); Bravo 0 a 43.8 c 14 ab 36.3 ab 2.7
Weather Stik, 2 pt (1-4)
5 Rally 40W, 5 oz (1,3); Quintec, 4 0 a 28.0 b 18 a 44.9 a 2.6
floz (2,4)
6 Bravo Weather Stik, 3 pt (1-4) 1.9 a 76.8 e 8b 18.2 c 2.3
7 Bravo Weather Stik, 1.5 pt (1,3); 1.1 a 83.9 e 11 ab 29.3 bc 2.6
Leml7 SC, 16 floz (2,4); Bravo
Weather Stik, 1 pt (2,4);
8 Bravo Weather Stik, 2 pt (1-4); 0.8 a 72.0 de 9 ab 21.8 bc 2.3
Actigard 50 WG, 0.33 oz (1,2),
0.50 oz (3), 0.75 oz (4)
9 EXPT 1, 3.4 floz (1,3); Procure Oa 62.5 d 18 a 44.8 a 2.6
480SC, 6 oz (2,4); Induce, 0.25%
(v/v) (1,3)
10 EXPT 1, 1.7 floz (1,3); Procure Oa 23.3 ab 16 a 36.6 ab 2.4
480SC, 4 oz (1,3); Quintec, 6 floz
(2,4); Induce, 0.25% (v/v) (1,3)
11 Rally 40W, 4 oz (1,3); Quintec, 6 0.4 a 43.8 c 17 a 36.6 ab 2.2
floz (2,4)
12 Non-treated Control 9.1 b 96.3 f 8 b 17.6 c 2.3
P>F 0.0002 < 0.0001 0.0016 0.0005 0.3155
Y Treatments (TRT) were applied 28-Apr, 5-May, 12-May, and 1-Jun corresponding with applications 1
to 4, using a backpack sprayer calibrated initially for 40, 60 and then 100 gallons per acre. Listed
treatment rates are on a per acre basis unless noted otherwise. Seeds were planted 25-Mar.
Y Values followed by the same letter are not statistically significant (P = 0.05).
z The severity of powdery mildew was assessed as the percentage of canopy affected. The Horsfall-
Barratt scale was used for all ratings, but values were converted to mid-percentages prior to statistical

Powdery mildew, caused by Sphaerotheca
fuliginea and Erysiphe cichoracearum, a disease favored
by the cooler, dryer conditions common during the

Please remember...
The use of trade names in this publication is solely for the purpose of
providing specific information It is not a guarantee or warranty of the
products named and does not signify that they are approved to the exclusion of
others of suitable composition Use pesticides safely Read and follow
directions on the manufacturer's label

Managing Yellow and Purple Nutsedge in
Florida Strawberry Fields
Andrew W. MacRae, Assistant Professor
Weed Science, Gulf Coast REC

As we continue our transition to methyl
bromide alternatives we will continue to see an
increase in weed problems in our strawberry
fields. Two of the more troublesome weeds
we expect to encounter will be yellow and
purple nutsedge (Figure 1). These weeds are
perennial weeds that spread via underground
roots called rhizomes and vegetatively
produced structures called tubers. These
tubers are produced in chains along the
rhizomes and can remain dormant in the soil
for several years. Yellow nutsedge produces
fewer but larger tubers than purple nutsedge.
When we fumigate we target these dormant
tubers to maximize the control of nutsedge.
Nutsedge is well adapted to grow in our
plasticulture production systems. It is able to
penetrate the majority of commercially used
plastic mulches and produces large numbers of
tubers by stealing the water and fertilizer
intended for our strawberry plants.

, i ,, 1. Purple nutsedge in strawberry field.

It is important keep any nutsedge
population as small as possible, even to the
point of having a zero tolerance policy on any
infestation. The grower should focus on year
round control to prevent a wide scale

establishment of this weed. This will
involve selecting and applying correctly a
good fumigant system, spot spraying of
nutsedge, post harvest herbicide and/or
fumigant applications, and fallow period
tillage/herbicide/cover crop programs.

For any areas of your field that have had
nutsedge problems in the past it is
important that you use a full fumigant
system. Fumigant systems consisting of
only 1,3-dichloropropene and/or
chloropicrin will not provide satisfactory
control of nutsedge. In long term testing
conducted in Georgia the use of these
systems actually increased the amount of
nutsedge present in the field after four
years of use. These systems may include a
combination of Telone II and 100%
chloropicrin or may come as pre-mix such
as products like Telone C35 and PicClor
60. Methyl Bromide 50:50 will provide
good control of nutsedge while Midas
50:50 will provide good to excellent
control and the soon to be registered
product Paladin Pic will provide excellent
control. The use of the 3-WAY system
consisting of Telone II plus chloropicrin
plus KPam or Vapam will also provide
good to excellent control. When using
KPam or Vapam a minicoulter rig will give
the best control of nutsedge; however if
using drip applications good control can be
achieved provided the grower uses two drip
tapes to maximize coverage of the bed.
Yellow and purple nutsedge will be
a major factor in future fumigation
decisions. Preventing this weed from
getting a foothold may allow a strawberry
grower to use a reduced fumigant system
provided they are willing to spend the time
to remove any nutsedge escapes from their
production fields.

In Crop
If you have nutsedge emerging through your
plastic mulch it is important to spot spray a
glyphosate product (Roundup, Touchdown,
Glyfos Xtra, etc.) to not only kill the top
growth but to also kill the tubers the plant is
producing. Hand pulling will only result in
removing the top growth and repeat pulling
may take all season before exhausting the
root reserves of an established plant.

Post Harvest
At the end of the growing season either an
application of a fumigant in the drip tape or a
post emergence application of a glyphosate
product will be needed reduce the population
of nutsedge tubers present in the soil. The
use of a fumigant can also help in reducing
disease and nematode populations.

Fallow Period
Maintaining control of nutsedge will require
an active management plan. The key is to
break the chain of nuts to maximize nutsedge
emergence at a time that you can apply
control measures. An example would be to
use tillage to break the chain and then
following that with an application of
glyphosate after the nutsedge shoots have
emerged. After you have knocked down the

population of nutsedge, then seed a cover crop
that will form a crop canopy quickly,
preventing further emergence of the nutsedge.
Broadleaf cover crops tend to develop thicker
crop canopies and are more suitable to limited
light from penetrating to the soil surface.
Initial infestation of nutsedge will be
noticed coming from the edges of the field
(Figure 2) and may get a foothold at the end of
the rows where the fumigant has not been
properly applied. It will be important to
maintain good weed management practices
around the edges of the field for not only
nutsedges but all weeds. A little bit of time
spent from now on can help reduce the
possibility of a nutsedge population increasing
to the point where a full fumigant system will
be required to keep the nutsedge population
below damaging levels.

Pesticide Registrations and Actions
* Based on a request by IR-4 and Syngenta,
the EPA has approved tolerances for the
insecticide thiamethoxam (Actara).
Tolerances of importance to Florida
include bushberry (blueberry), canistel,
small climbing fruit (except fuzzy kiwi
fruit), mango papaya, rice, sapodilla, black
sapote, mamey sapote, star apple, and root
vegetables (subgroup 1A). (Federal
Register, 9/30/09).
* On October 5, the Florida Department of
Agriculture and Consumer Services
accepted EUP submitted by Pasteuria
Bioscience, Inc., which allows the use of
the nematicidal active ingredient Pasteuria
usgae on strawberry and turf to evaluate
control of sting nematode. (FDACS letter,

Fi ..- 2. Purple nutsedge infestation 'il, i,. from
the edge of the field.

New, web-based tool to aid disease
control available for strawberry
Natalia Peres, Assistant Professor Plant Pathology
GCREC; Clyde Fraisse, Assistant Professor Biological
Engineering GNV; and Willingthon Pavan, Assistant
Research Scientist Biological Engineering GNV

A new, web-based tool to help growers
to time their fungicide applications is now avail-
able. The web decision support system can be
accessed at http ://aroclimate. org/tools/
strawberry/. The system gives information on the
current risk level for the two most important fruit
rot diseases in Florida, Botrytis (or gray mold)
and anthracnose, and makes recommendations on
the timing of fungicide applications for control
of those diseases.
The disease models that were used to develop the
web-based system have been tested in field re-
search trials for the past four seasons. In most
cases, the number of fungicide applications was
reduced to about half compared to the currently
preventive spray program without any significant
loss of disease control or yield. Thus, the use of
the system can significantly help growers to re-
duce the number of sprays and the cost of pro-
duction, especially in years when the conditions
for disease are not favorable.
When growers go to the website, the first
page displays a map showing the currently avail-
able weather stations in the system. Those are
part of the Florida Automated Weather Network
(FAWN) and are located at Dover, Balm, Lake
Alfred and Arcadia. The stations are displayed
with different colors to quickly show the current
disease risk level (green: no risk, yellow: moder-
ate risk or red: high risk). By passing the mouse
over the stations, the user can check which spe-
cific diseases are affecting that area.
When conditions for disease are moder-
ate or high, users can click on the station symbol
and then on the link to check for a more specific
spray recommendation. A few questions about
previous fungicide applications and the stage of
crop development will then need to be answered.
Once the responses are entered, the system ap-

plies the rules and gives a spray recommenda-
tion for each disease, including a list of possi-
ble products to use.
A 'Disease simulation' tab presents the
outputs for disease risk levels throughout the
season as well as the forecast for the next 3
days in graphic and table formats. A display of
weather data observed during the last 48 hours
and forecast for the next 24-hours (provided by
the National Weather Service) can also be
found under the 'Weather' tab.
E-mail and cell phone text messages
(SMS) are also available during the season for
growers who register for those options. This
service is automatically activated to send alerts
when disease risk reaches moderate or high
We would like to encourage growers to
test this system to manage diseases on a small
acreage of your farm so that you can gain ex-
perience and confidence in this new tool. The
system is simple to operate and very user
friendly. On a small trial in a commercial
strawberry farm last season, the grower saved
about 50% on fungicide related costs by using
this tool. Overall, the use of the tool will offer
growers the same level of disease control with
less applications of fungicide but the potential
savings will vary according to the weather con-
ditions. Thus, it is possible that fungicide
sprays won't be reduced as much in a wetter
season under influence of El Nifio conditions
such as the current one.
Project funds to develop this system
were granted by the USDA-RMA (Risk Man-
agement Agency). Future grants for enhancing
the system that would allow the addition of
more weather stations for greater accuracy are
being sought.
Finally, if you haven't yet, check it out
the tool at http://agroclimate.org/tools/
strawberry. If you are interested in receiving E-
mail and/or text messages when the anthrac-
nose or Botrytis risk level exceeds the thresh-
old, please contact Dr. Natalia Peres
(nperesufl.edu), Dr. Clyde Fraisse
(cfraisse(ufl.edu) or Dr. Willingthon Pavan
(wpavanufl. edu).

Crown Rot (Charcoal Rot) of Strawberries
Caused by Macrophomina phaseolina
Natalia A. Peres and J.C. Mertely

Crown rot of strawberries, also known as charcoal rot, caused by Macrophomina phaseolina, is a
relatively new disease in Florida. This disease was first observed in December 2001, when collapsed and
dying strawberry plants from a commercial field were submitted to our Diagnostic Clinic. During the
2003-2004 season, M phaseolina was isolated from dying strawberry plants taken from the original
field and two additional farms. Since then, a few additional samples are received in our Diagnostic
Clinic every season. Affected plants are often found along field margins or other areas inadequately fu-
migated with methyl bromide. Charcoal rot has also been reported on strawberry in France, India, and

Causal Agent and Symptoms
Symptoms caused by Macrophomina phaseolina are similar to those caused by other crown-rot
pathogens such as Colletotrichum and Phytophthora species. Plants initially show signs of water stress
during warmer periods of the year and subsequently collapse (Fig. 1). The cut crowns of affected plants
reveal reddish-brown necrotic areas on the margins and along the woody vascular ring (Fig.2). The fun-
gus produces tiny black knots of mycelium (sclerotia) that allow it to persist in the soil even when host
plants are unavailable, making it an adaptable and persistent soil pathogen. To confirm a diagnosis, a
sample must be submitted to a Diagnostic Clinic and the pathogen must be isolated from the diseased
crowns and identified.

Disease Development and Spread
Very little is known regarding this disease on strawberries. M phaseolina is a common soil-
borne pathogen in many warm areas of the world and has a very broad host range. Many vegetable crops
planted as second-crops after strawberry such as squash, cantaloupe, and peppers, among others, are sus-
ceptible. In addition, legumes planted as summer crops are also susceptible. Those infections may in-
crease inoculum levels ofM phaseolina in the soil. In general, high temperatures and low soil moisture
favor infection and disease development.

No fungicides are labeled for control of charcoal rot on strawberries. Topsin 'I' is labeled for ap-
plication through the drip lines for charcoal rot control on cucurbits. Although Topsin is labeled for
foliar application to strawberry, it is not labeled for drip application. Our preliminary results with Topsin
I' have shown that injection of this product early in the season when warm weather and transplant
stress favor disease may help delay onset of symptoms. Studies are currently being conducted to test this
and other chemical and biological products for control and also to determine if cultivars differ in suscep-
tibility to charcoal rot. This disease may be an emerging threat as the Florida strawberry industry transi-
tions from methyl bromide to other fumigants.

Fig. 1. (right) Plant wilting
symptom of charcoal rot.

Fig.2. (left) Internal crown
symptoms of charcoal rot.

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