Group Title: Berry/vegetable times.
Title: Berry/vegetable times. July 2005.
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Title: Berry/vegetable times. July 2005.
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: July 2005
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Volume ID: VID00036
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July 2005

A monthly newsletter of the University of Florida IFAS
Florida Cooperative Extension Service,
Hillsborough County
5339 CR 579, Seffner, FL 33584
(813) 744-5519 SC 541-5772
Alicia Whidden, Editor Mary Chernesky, Director
Gulf CoastResearchandEducation Center
14625 County Road 672, Wimauma, FL 33598
(813) 634-0000 SC514-6890
Christine Cooley, Layout and Design
Craig K Chandler, C oEditor
Jack Rechcigl, Center Director

From Your Extension

On August 16th and
17th the 2005 Strawberry
Agritech Educational Session
and Trade Show will be held
at the Florida Strawberry
Festival Grounds in Plant City.
A variety of talks informing
growers of the latest
regulatory issues and IFAS
research trials are slated. Also
available will be sets of
questions from Citrus and
Vegetable magazine CORE
CEU articles that have been
published so far this year.
These articles are sponsored
by chemical companies with
Bayer being this year's
sponsor and the magazine.
Articles are written by
Extension agents to give
growers an easy way to get
restricted pesticide license
CORE credits. Articles can be
found on-line. All you need to
do is read the article and
answer the questions, then
send the completed test to the
author of the article to grade.
A score of 70 or better is
needed to get 1 CORE credit.
For a restricted pesticide
license to be renewed you now
need 4 CORE and 4 private
applicator CEUs every 4

years. This is an easy way to
get all the question sets in one
place and be able to do them at
your convenience and meet
your pesticide license CORE
Looking forward to
seeing you at Agritech!

Alicia Whidden
Hillsborough County Extension
813-744-5519, ext. 134

Oberon Miticide/
Insecticide Approved
for Strawberries
Jim Price, Silvia Rondon and Curtis

The approval by EPA
and FDACS for Oberon' 2 SC
miticide/insecticide by Bayer
CropScience is welcomed
since it has proven itself to be
an excellent control agent for
twospotted spider mites and
whiteflies in several years of
work at GCREC Dover and
Bradenton. Oberon's
spiromesifen active ingredient
represents a new mode of
action (inhibitor of lipid
synthesis) and new class of
compound (cyclic tectronic
(Continued on page 2)

IFAS is an Equal Employment Opportunity Affirmative Action Employer authored to provide research, educational information and other services only to individuals and institutions that
function without regard to race, color, sex, age, handicap, or national origin U S Department of Agnculture, Cooperative Extension Service, University of Flonda, IFAS, Florida A & M
Umnversity Cooperative Extension Program, and Bloards of the County Commissioners Cooperating

July 2005

BerryNegetable Times

Berry/Vegetable Times

acids) for strawberries and can be a good
rotational partner with other miticides of
diverse modes of action.
Oberon" is a non-systemic, contact
pesticide active against spider mite eggs and
all the other developmental stages; however
immature mite stages are most susceptible. In
addition to control of twospotted spider mites,
it controls immature whiteflies, emerging pests
of strawberries. It cannot be used in
greenhouses in Florida.
Oberon" is compatible with Florida's
strawberry culture. The pre-harvest interval
(PHI) is 3 days, field re-entry interval (REI) is
12 hours, and three applications may be made
per crop season at as close as 7 day intervals.
Treated areas can be planted back immediately
to fruiting vegetables, leafy vegetables and
cucurbits, which include most of the second
crops that traditionally follow strawberries in
the Plant City area.
The label carries a "Caution"
precautionary statement and product will be
available in time for the 2005-06 strawberry
season. We look forward to integrating this
additional miticide into our strawberry culture.

Hillsborough County Extension Service Factsheet 05-2
Required Workplace Posters
P. R. Gilreath and A. J. Whidden, May, 2005
(Source: Florida Fruit & Vegetable Association, Florida
Strawberry Grower's Association)

The following are posters which should
be posted at the work site. Most can now be
downloaded and printed from the websites
listed. Phone numbers are also included for
additional information. Please note that FFVA
and FSGA does provide some posters for their
members. This list also includes some optional
posters and information on the WPS poster.
The following six posters can be
printed from the Poster Page of the U.S.
Department of Labor at
osbp/sbrefa/poster/main.htm (Or call 1-866-

USWAGE or 1-866-487-9243)

?? Family & Medical Leave Act Needed if
you hire 50 or more people at any one time
during the year within a 50 mile radius.
?? Fair Labor Standards Act Federal
Minimum Wage. You must now have the
state poster as well. It is not available
online but should be available from your
commodity organization and the law goes
into effect May 2, 2005.
?? Job Safety & Health Protection- OSHA
Health & Safety.
?? The Law: Equal Employment
Opportunity Commission.
?? MSPA Migrant & Seasonal Worker
Protection Act.
?? Uniformed Services Employment
and Reemployment Rights Act. (A
new poster)
?? Unemployment Compensation (From
your insurance carrier)W
?? Workers' Compensation (get this from
your carrier broken arm poster)
?? Florida Human Relations Commission. (Tallahassee, 850-
488-7082 or 1-800-342-8170 for voice
messaging) This poster not available
online. Call the commission for a copy.
?? Florida Child Labor (needed only if
anyone under 18 is hired) (FL Dept of
Labor, Tallahassee, 850-488-3131) http//
?? Tractor Decals (Spanish and English,
side-by-side) (These are available from
FFVA to members only. This is
supposedly related to an OSHA Training
requirement, although when I called
OSHA, they did not have it on their list of
required posters.)
?? Protect Yourself from Pesticides (EPA
WPS Poster) (Can be ordered from
Gempler's along with other WPS materials
at 1-800-382-8473)
?? WH-516 (this is not a poster, but a MSPA
disclosure statement that you can post.
Form WH-516 English.PDF

July 2005

Berry/Vegetable Times

New Molecular-Genetic Resources
for Strawberry Research
Kevin Folta, Molecular Biologist
Horticultural Sciences Dept., University of Florida

Despite its value as a crop plant,
relatively little is known about the molecular
mechanisms that affect strawberry form and
function. Most of what is understood comes
from studies of model plant systems such as
Arabidopsis thaliana, a laboratory-friendly
weed species with a sequenced genome, rapid
life cycle, and compact growth habit. Gene
constructs may be easily added, and public
repositories of mutants are extensive.
Arabidopsis has taught us much about
processes important to plant growth and
development, yet has no direct relevance to
The current challenge to researchers is
to translate the wealth of fundamental
information from the model systems into
studies in species of interest. Molecular-
genetic endeavors have characterized genes
involved in critical plant processes (flowering,
disease, fruit development) in many crop
species. Hundreds of thousands of fruit-crop
gene sequences have been obtained from
citrus, peach, apple, grape and many other
species. But, relatively little comparable
research has been performed in strawberry.
Research directives at the University of

Florida's Horticultural Sciences Department
seek to correct the dearth of information in
cultivated strawberry. Newly-developed
resources have expanded the public databases
and present new research tools that promise to
speed development of molecular markers for
genetic mapping, the discovery of new genes
important to strawberry (and other species) and
expand the understanding of plant traits critical
to efficient production in today's challenging
The first resource is a database of
Expressed Sequence Tags (ESTs) and Simple
Sequence Repeats (SSRs) from strawberry. In
early 2004 only 54 strawberry gene sequences
existed in the public domain. Generous
funding from the North American Strawberry
Growers Association and the Horticultural
Sciences Department funded the production of
an EST library, a collection of sequences from
expressed genes. Over 1800 genes were
sequenced, analyzed and immediately
deposited to public databases. The results of
these analyses are presented in a recent report
in BMC- Plant Biology (5:12). Briefly, genes
sequences associated with control of
photoperiodic flowering, disease, stress, and
general metabolism have been isolated from
strawberry, and now serve as a basis to test
gene function. Comparisons were made to
genes isolated from other plants in the rose

(Continued on page 4)

The Laboratory Festival #9 genetic line is a promising tool for development of transgenic plants for strawberry research. A
1cm petiole is removed from the plant, sterilized with bleach and placed onto media containing a lpei itic combination of
growth regulators (top ;r r' Within days changes in cell identity and growth are observed (bottom left panel; left side ofpetiole
segment). After 35 days in culture the petiole segmentproduces tens to hundreds of shoots, each a clone of the parental line
(middle panel). The panel on the right shows a juvenile plant in culture after approximately 90 days.

July 2005

Berry/Vegetable Times

family, suggesting a short list of strawberry
specific genes. With this basic parts list, it is
now possible to test what was learned from
Arabidopsis and other model systems in
strawberry. The SSRs have been used as
molecular markers, allowing integration of
gene sequences of known function onto the
strawberry genetic linkage map.
The other new tool is the LF9 genetic
line. LF9 stands for "Laboratory Festival #9"
a plant produced from a 'Strawberry Festival'
self-pollination, selected in the laboratory for
robust growth in culture. This plant line
readily accepts bacterial insertion of new
genes, allowing for studies of gene function.
The LF9 line has attracted great interest from
the Rosaceae (rose family) research
community as it represents a vehicle to finally
test the role of specific genes in a Rosaceae
background on the scale of months instead of
years. The most tangible roles for this line lie
in the creation of strawberry lines harboring
mis-expressed genes of interest. These studies
promise to add resolution to understanding the
molecular mechanisms associated with
photoperiodic flowering, fruit ripening, yield,
disease resistance and a host of other
agriculturally-relevant traits.
The EST database and the LF9 genetic
line represent only two of emerging
technologies that will facilitate translation of
new molecular-genetic paradigms to cultivated
strawberry. The current research goals are to
create a means to understand gene function,
map genes in the cultivated strawberry
background, and then implement use of
transgenic (gene insertion) tools and new
genetic markers to assist in cultivar
improvement. Such technologies promise to
assist breeders, growers and the industry adjust
to changes in policy and practice with even
greater speed and agility.

Recent Experiments Yield New
Ideas: Comparing Strawberry
Jim Mertely, Craig Chandler, and Natalia Peres

Last season, several field experiments
were carried out in Dover to find better ways
to control strawberry diseases. Some of our
findings were surprising. Results from our
most recent variety trial are summarized in this
In October 2004, five strawberry
cultivars were planted in a replicated field trial
at Dover. The five cultivars were Camino
Real, Condonga, Strawberry Festival, Sweet
Charlie, and Ventana. The experimental area
was tractor sprayed weekly throughout the
season with a low rate of Captan 80WP (1 7/8
lb in 100 gal/A) to maintain a minimal level of
disease control. During the early season, plots
were harvested regularly, but no data was
taken. Fruit from the ripening between
February 21 and March 31 were harvested
twice weekly, and graded to determine
marketable yield, weight of marketable berries,
and the percent of fruit infected by
anthracnose, Botrytis, and powdery mildew:
Yields of marketable fruit were highest
for Festival and Ventana, and lowest for Sweet
Charlie. While no early season data was taken,
Ventana started fruiting later and was probably
out-produced by Festival in December and
January. Many Sweet Charlie plants in this
trial were stunted and reddish from the onset
due to infection by Strawberry Mild Yellow
Leaf and possibly other viruses. In addition,
Sweet Charlie is an early season cultivar which
typically "plays out" in March when most
yield data from this trial was gathered.
As expected, the California cultivars
Camino Real and Ventana produced larger,
heavier fruit than the Florida cultivars Festival
and Sweet Charlie. The Spanish cultivar
Condonga also produced larger fruit, although
many had green shoulders during the cooler
parts of the season.
(Continued on page 5)

July 2005

Berry/Vegetable Times

Environmental conditions from
January to March 2005 encouraged the devel-
opment of Botrytis fruit rot, but suppressed the
spread of anthracnose. Nevertheless, the inci-
dence of anthracnose fruit rot was sufficient to
demonstrate the high resistance of Sweet Char-
lie to this disease. In addition, Festival
proved more resistant to anthracnose than Ven-
tana, but not significantly more resistant than
Camino Real. Festival was also moderately


Fruit wt

resistant to Botrytis, while Camino Real and
Ventana lost large numbers of fruit to Botrytis
fruit rot. Powdery mildew typically appears on
the foliage early in the season and on the fruit
later on. In our trial, the powdery mildew fun-
gus grew conspicuously on the seeds of some
Condonga and Sweet Charlie fruit, but oc-
curred less frequently on Camino Real, Festi-
val, and Ventana.

Percent fruit

Camino Real 12,500 b 22.6 a 46.7 b 6.3 bc 37.6 d 0.5 a
Condonga 12,000 b 22.3 ab 45.5 b 6.2 bc 13.8 a 11.0 c
Strawberry Festival 15,000 a 16.7 c 33.3 a 3.6 b 13.3 a 1.8 ab
Sweet Charlieb 6,700 c 16.0 c 67.4 c 0.5 a 17.5 b 10.5 c

Ventana 15,300 a 21.1 b 51.8 b 9.7 c 32.4 c 2.4 b

Application Considerations for
Reduced Rates of Methyl Bromide
with VIF and Metalized Mulch Film in
Vegetable Production
James P. Gilreath, GCREC-Balm
Phyllis R. Gilreath, Manatee County Extension Service
Bielinski Santos, GCREC-Balm

The amount of methyl bromide in 350
lb. of a 67:33 methyl bromide:chloropicrin
(w:w) formulation is about 235 lb. of actual
methyl bromide. This rate of 235 lb. of methyl
bromide per treated acre (field rate) is thought
to be the lowest rate for maintaining good
nutsedge control under typical application
conditions. This is based on use of methyl
bromide with standard low or high density
polyethylene (ldpe or hdpe, respectively) film
mulch which has low retention capacity for
methyl bromide.
Over the past 6 years, considerable
research has been conducted with virtually

impermeable films (VIF) which have much
higher fumigant retention capacity compared
to Idpe and hdpe. Research and grower trials
with tomato and pepper have established that
methyl bromide rates can be reduced by one-
half with VIF products and still maintain
nutsedge control and crop yields comparable to
those achieved with a full rate with standard
film. Unfortunately, there are 2 drawbacks to
most VIF products: cost and handling
characteristics. Today, all VIF is made in
Europe and must be imported, thus resulting in
much higher cost than standard film. Also,
most VIF products are more difficult to lay
than standard films in that they are prone to
linear sheer under too much tension. Handling
characteristics among VIF materials differ
significantly, but all are based on polyamides,
such as nylon, for their barrier properties and
these polyamides do not stretch well. Also,
none are embossed at the present time.
(Continued on page 6)

July 2005






Berry/Vegetable Times

In the past 2 years, we have examined
the barrier properties of metalized films under
field conditions, first with Inline and more
recently with methyl bromide. In each case,
application of Inline or methyl bromide in
conjunction with metalized film greatly
increased the retention of the fumigant. In the
case of methyl bromide, nutsedge control was
obtained with 175 lb/acre of 67:33 under
Canslit metalized film that was equal or
superior to that obtained with the full 350 lb/
acre rate under standard Idpe or hdpe film in
each of four experiments. Grower trials
confirmed these results. The retention of
methyl bromide and resultant nutsedge control
with Canslit metalized film was similar to what
we obtained with VIF at every rate of methyl
bromide, ranging from 88 to 350 lb/acre of
While it is possible to use VIF or
Canslit metalized film to reduce methyl
bromide rates by one-half, successful use
involves more than just reducing gas flow and
laying mulch film. Methyl bromide has a high
vapor pressure, which means that at typical
application temperatures it rapidly becomes a
gas and can do so even within the tubing and
gas knives. This is an advantage for reduced
rate application, but does not solve one
inherent problem uniformity of application.
Typical gas rigs employ 3 knives per bed. A
good fumigation job requires that all 3 knives
deliver the same amount of product per minute
so the application rate is uniform in the area
being fumigated. When the rate is reduced,
there is less fumigant in the system and more
opportunity for the formation of bubbles as the

Fig. 1. Various diameter tubing for fumigant
dehvery to chisels.

methyl bromide "boils." This "boiling" easily
can be visualized by inserting small sight
glasses in the application equipment at the
flow divider just ahead of the tubes which
carry the fumigant to the knives g_. 1).
Under normal conditions, a certain amount of
back pressure exists in the application system
and can be measured at the flow divider by
installing a pressure gauge. Application of a
full 350 lb/acre rate will generate in excess of
30 psi of back pressure at this point. Reducing
the methyl bromide flow rate to deliver lower
rates per acre will reduce the back pressure
measured at the flow divider. Our experience
indicates that back pressure below 15 psi
results in nonuniform distribution to the three
knives which means inequalities in rate across
the bed. Usually the edges suffer the most and
this can be observed later in the season as poor
nutsedge control on bed shoulders.
To increase back pressure when using
low rates of methyl bromide or any other
fumigant, you must decrease the flow capacity
of the delivery system between the flow
divider and the gas knives. This can be
accomplished in two ways. First, you can use a
smaller diameter tubing to deliver fumigant to
the gas knives. Standard gas rigs use inch
inside diameter tubing. We have found the use
of poly tubing ranging from 1/16 to 1/8 inch
inside diameter is necessary to achieve
balanced or uniform delivery of greatly
reduced rates of methyl bromide. Tubing of
this size is not readily available, but can be
obtained and is an important modification for
using reduced rates of methyl bromide with a
highly retentive film. Fine tuning of flow
capacity or rate of any tube can be
accomplished by increasing or decreasing the
length of the tube connecting the flow divider
to the gas knife. There is some amount of
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 names and does not signify that they are approved to the
exclusion ofothers ofsuitable composition. Use pesticides safely.
, directions on the manufacturer's label.

July 2005

Berry/Vegetable Times

friction loss within any size tube which
increases with increased length and decreased
tubing inside diameter. Typical length for 1/16
and 1/8 inch tubing is 5 ft, although longer
tubing has been used when trying to achieve
really low rates. Color coded tubing is
available which can be a big help when
adjusting flow rates. Yellow tubing has the
thickest walls and smallest inside diameter of
1/16 inch. Black tubing is available in 1/8 inch
inside diameter (Fig. 2). These tubes all fit the
same size connector, making it easy to switch
from one flow capacity to another. Select the
tube needed for the desired flow capacity; once
installed, adjust the flow regulator valve for
the required flow rate on the flow meter.

Fig. 2. Flow divider with sight glasses and pressure
A second way to decrease flow and increase
back pressure is to use orifice plates (Teejet
flow regulators) in the tubing at the top of the
gas knife fitting. To use these plates, you have
to know what flow rate you need in each tube.
Since the flow rates of orifice plates are based
on water, you have to do some mathematical
conversions to methyl bromide or choose one
on the high side and try it. Do not use a plate
with the exact same flow rate as desired; a
slightly higher flow rate is necessary so that
clogging potential is lowered. The plates are
stamped with numbers that indicate the size of
the hole in the plate ig 3). It is
recommended to keep a supply of various sizes
on hand. Orifice plates work over a more
narrow range of rates than tubing does,
because the restriction in flow occurs at one
point rather than over a length of tubing.
The system we use is commercially
available (manufactured by Mirruso

Enterprises, Inc., available through Chemical
Containers, Inc.) and constitutes an easily
installed, simple modification. It consists of a
flow divider with a small sight glass for each
knife, a 0 to 30 psi pressure gauge and small
diameter poly tubing. The sight glasses are
equipped with standard quick connect (insert
friction connectors) couplings on top so the
poly tube can be connected and disconnected
easily. Similar couplings are located on the top
of the gas knives. Sight glasses allow you to
monitor flow and detect plugging of chisels or
lines. Plugging can be a significant issue with
low rates of fumigant; thus, fumigant filtration
is important and filters must be checked
periodically and maintained free of debris to
assure consistent flow.
When using reduced rates of fumigant,
the flow rate has been greatly diminished so
accuracy and uniformity of delivery are
critical. A common observation on commercial
farms is tractor movement as soon as the
fumigant flow valve is opened. There is a
much longer delay in supplying all the knives
uniformly when the rate is reduced, so tractor
movement should not begin until all lines are
fully charged. This condition can be easily
monitored by observing the sight gauges and
back pressure gauge. Once the back pressure
stabilizes, fumigation can begin. Addition of
an inline check valve at the top of each gas
knife can be beneficial because it diminishes
loss of fumigant out of the line to the knife. By
keeping the line full all the way to the gas
knife, there are fewer delays in fumigant
delivery and less time wasted purging air from
lines. This would be especially important for
those growers who use radar controlled
fumigant delivery systems.
Rate reduction with methyl bromide
works when combined with a highly retentive
mulch film like VIF or metalized film. In
addition to the use of the right film, success
requires close monitoring, assuring not only
the correct rate, but also uniform delivery to all
three knives in the bed. Nonuniformity
guarantees poor fumigant performance at any

July 2005

Berry/Vegetable Times

rate, but with reduced rates of methyl bromide,
the results can be even more dramatic. The
simple modifications described above can
greatly improve uniformity of delivery and
performance. These modifications are
relatively inexpensive and are readily available
as a package. Before trying rate reductions,
growers should modify their fumigation
equipment to allow better control over
uniformity of flow. This can mean the
difference between success and failure.

Selectivity of Spinosad (Spintor)
Chemically Speaking June 2005

Pesticide levels previously thought to
be safe for pollinators may prove harmful to
wild bee health, according to research
published in May's Pest Management Science.
The Canadian study shows that adult bumble
bees exposed to the pesticide spinosad during
larval development-at environmentally
relevant concentrations-have impaired
foraging ability. Bees are important
pollinators of crops. In developed counties,
approximately a third of human food is reliant
on pollinating activity. Wild bees are thought
to contribute significantly to this effort.
Although many pesticides are known to
be toxic to bees, toxicity testing is largely
restricted to direct lethal effects on adult hony
bees, if tested on bees at all. Sub-lethal effects
on honey bees could be going unnoticed, and
other bee species could be differentially
affected. Lora Morandin and colleagues at
Canada's Simon Fraser University tested the
effects of different levels of spinosad on
bumble bee colony health and foraging ability.
Bee colonies were fed the pesticide in a
manner that mimicked contact in an
agricultural setting. Adult bees and developing
larva were exposed to spinosad in pollen. The
bees foraging ability on an array of "complex"
artificial flowers made of centrifuge tubes was
then evaluated. High levels of spinosad
residues (about 10 times what bees should
experience in the environment) caused rapid

colony death. Colonies exposed to more
realistic levels of spinosad in pollen did not
show any acute effects and only minimal
immediate colony effects. However, bees that
were fed realistic levels of spinosad during
larval development were slower foragers.
They took longer to access complex flowers,
resulting in longer handling times and lower
foraging rates. The bees also displayed
"trembling", which impaired their ability to
land on the flowers and enter the flower tubes.
This impaired foraging ability in bumble bees
could result in weaker colonies and lower
pollination of crop plants, according to
Morandin. "Adult bees that have been
exposed to a pesticide during larval
development may display symptoms of
poisoning that are not detected with current
tests required by regulatory agencies." (Society
of Chemical Industry 5/6/05).

Pesticide Registration and Actions
Chemically Speaking June and May 2005
?? On April 8, the FDACS issued the Special
Local Needs registration SLN FL-05001 to
Syngenta for Switch fungicide
(cyprodinil + fludioxonil). The registration
is for a reduction in plant back restriction
(from 12 months to 30 days) for plants not
on the label. Plants on the label can be
planted anytime after the last application.
(FDACS PREC Agenda, 5/5/05.)
?? The EPA has approved a specific
exemption for the use of thiophanatemethyl
(Topsin M) fungicide for management of
white mold (Sclerotinia sclerotiorum) on
fruiting vegetables (tomato, pepper,
eggplant). The exemption runs from April
8, 2005 to April 7, 2006. (FDACS letter of
?? Based on a request by Bayer CropScience
tolerances are approved for the insecticide
spiromesifen. This is a spirocyclic phenyl-
substituted tetronic acid that is effective
against whiteflies and mites, with juvenile
stages more severely affected. Tolerances
of importance to Florida include cotton,
seed, strawberry, tomato paste, brassica

July 2005

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