J0f UNIVERSITY of
A monthly newsletter of the University of
5339 CR 579, Seffner, FL 33584
(813) 744-5519 SC 541-5772
Alicia Whidden, Editor
Mary Chernesky, Director
Gulf Coast Research
and Education Center
14625 County Road 672,
Wimauma, FL 33598
Christine Cooley, Layout and Design
Craig K. Chandler, Co-Editor
Jack Rechcigl, Center Director
From Your Extension Agent-
Summer Blueberry Care
The pruning given to blueberry plants after harvest is
to encourage branching and greater leaf canopy so the plant
can set a greater number of flower buds for next year's
harvest. It is important to have your plants grow as vigorous
as possible during the summer and to hold the leaves till late
fall. As much as you may want to just go stay in the air
conditioning until cooler weather gets here your plants will
need attention from you to help get the most growth possible.
First is soil moisture. It may be the rainy season but
as we have seen this July and August there can be prolonged
times with little or no rain and very high temperatures.
Blueberries are planted in pine bark which drains very well;
translate that to: it dries out quickly, and a small amount of
rainfall may not be enough. This is very true when you are
(Continued on page 3)
Methyl Bromide Alternatives, High Barrier
Mulches, and Reduced Rate Application
Technologies: What Growers Should be
Considering for the Fall!
J.W. Noling, Alicia Whidden, and J.P. Gilreath
The price of methyl bromide, like that of gasoline and
diesel, has now exceeded the $3.00 benchmark. This was not
unexpected as we have previously reported, since the methyl
bromide price is a direct function of supply and demand. As
CUE approved levels and existing supplies of methyl bromide
(stocks) are reduced, prices have increased and will continue
to do so as long as demand remains high. There are ways,
however, to reduce methyl bromide costs, and this is the
subject of this newsletter article.
(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
University Cooperative Extension Program, and Boards of the County Commissioners Cooperating
This past spring we conducted a
field day at the FSGA research farm to talk
about methyl bromide price and
availability and to introduce some new
plastic mulch products. All of these plastic
mulch products were high barrier and
virtually impermeable (VIF) to diffusion of
methyl bromide and other fumigant gases.
Previous research has demonstrated that
field application rates of methyl bromide
can be reduced by as much as 50 percent
without problem or yield penalty. The
purpose of the field day was also to
demonstrate that the mulches could be
rapidly played in the field without problem
or tractor stoppage. A list of the mulch
products which provide enhanced
containment of methyl bromide and will
allow field application rate reductions of as
much as 50% are listed in Table 1. The
list may not include all VIF mulches
commercially available. Growers are
strongly encouraged to contact the
distributors of these products for pricing
information and field evaluations this fall.
The savings derived from reduced rates of
methyl bromide application should more
than compensate for the added material
costs for any of these high barrier mulches.
There are other reasons besides cost
to reduce fumigant field application rates
and to use high barrier mulch. We believe
that new EPA regulatory decisions
regarding the re-registration of the
alternative fumigants (metham sodium,
chloropicrin, methyl iodide, dazomet, and
others) will absolutely require very
dramatic reductions of field application
rates. In our opinion, this will mandate use
of high barrier mulch films and reduced
rate fumigant application technology on the
part of growers. For this season, it is still
not too late to trial an alternative fumigant
like Telone C35 at a reduced rate (17 gal/
treated acre) with the high barrier mulch.
At some point we will have to
accept the use of an alternative fumigant and
the sooner we begin the evaluation with high
barrier mulch the better off we will be.
Table 1. Manufacturing and or Distribution
Sources of High Barrier/Virtually Imperme-
able Plastic Mulch Films.
Atofina Chemical Inc.
2000 Market Steet, Philadelphia, PA 19103-3222
PH: (215) 419-7000 FAX: (215)419-7591
1 (800) 225-7788
Bruno Rimini Corp.
305 Ballards Lane London N12 8 NP
PH: +44 (0) 20 8446 3646
FAX: +44 (0) 20 8446 7654
Florida Distribution: Intergro Inc.
Attention: Jim Stoutz
Klerk's Plastic Products Manufacturing Inc.
546 L & C Distribution Park, Richburg, S.C. 29729
PH: (803) 789-4000 FAX: (803) 789-4001
Florida Distribution: Intergro Inc.
Attention: Jim Stoutz
(813) 245-8799 (800) 783-0416
BLOCKADE VIF www.pliant.com
Florida Distribution: Pliant Sales Representative
Attention: Dennis Sutton
2007 74th NW, Bradenton, FL 34209
PH: (941) 761-8293 FAX: (941) 792-5603 Mobile
GINEGAR OZGARD VIF www.ginegar.com
Ginegar Plastic Products LTD.
Florida Distribution: Crop Protection Inc.
Attention: Charlie Young
2607 Sammond's Road, Plant City, Florida
PH: (813) 754-3083 Fax: (813) 754-3896 Mobile
CANSLIT BLACK METALIZED MULCH
Imaflex Inc. / Canslit Inc.
5710 Notre Dame West
Montreal, Quebec, Canada H4C 1V2
Tel: (514) 935 -5710 FAX: (514) 935-0264
Florida Distribution: Intergro Inc.
Attention Jim Stoutz
(813) 245-8799 (800) 783-0416
Table 2 Summary of recommended fumi-
gant injection equipment modifications re-
quired for use of high barrier / VIF mulch and
reduced rate applications of soil fumigants.
Replace tubing from manifold to chisels
with smaller diameter poly tubing to
compensate for the new reduced
flow capacity requirement and to
increase line back pressure needed
to insure accurate, uniform flow. (ie.,
yellow, red, or black polytubing.
To the manifold flow divider, install indi-
vidual sight gauges to observe uni-
formity of fumigant liquid flow to
each chisel outlet.
Install a low pressure gauge (0-30 psi)
immediately upstream of the mani-
fold or flow divider to insure at least
15 psi of backpressure.
Insure that the flow meter registers a
minimum of 10% flow
At the UF IFAS / FSGA field day in
May, we also stressed how successful use
of high barrier VIF mulch involves more
than just reducing gas flow and laying the
more gas impermeable mulch film in the
field. Reduced rate applications requires a
new level of sophistication and application
technology, such as changes in fumigant
metering and flow systems, as well as
balancing gas flow between chisels by
ensuring sufficient back pressure on each
gas delivery line by reducing line size from
the manifold to the gas knives. Table 2
summarizes application and fumigant
injection equipment modifications required
to use high barrier / VIF plastic mulch.
These are but a few new considerations and
equipment modifications required to
successfully use VIF and reduced rates of
methyl bromide or any other fumigant. We
want to encourage growers who plan to use
the high barrier VIF mulches to contact
their fumigant distributors and address
these issues before the strawberry
fumigation season begins in late August.
For additional, more comprehensive
information, growers are also encouraged to
review "Application Considerationsfor
Successful Use of VIF and MetalizedMulches
, i/h Reduced Fumigant Rates ". http.//
(Continuedfrom page 1)
growing in pots. Pay attention to the moisture in
the root zone no matter what growing system
you use. Be sure plants are staying well watered,
whether from Mother Nature or you.
After you have made sure your plants are
receiving enough water, you need to provide
adequate fertilizer so the plant is able to grow
lots of leaves and set the maximum flower buds
in the fall. Fertilizer is very susceptible to
leaching from heavy rains. The use of slow
release fertilizer helps prevent leaching of
nutrients in heavy rain and you don't have to
apply as often. This is the least labor intensive
method of fertilization but is the most expensive.
Just be sure you still have adequate amounts for
good summer growth; heavy rainfall and high
temperatures will release fertilizer faster. You
may need to replenish your slow release fertilizer
or use another type such as dry or liquid. Dry or
liquid fertilizer is cheaper but both are easily
leached and must be applied more frequently.
Be sure you are giving adequate amounts
through the summer so plants can achieve
maximum growth. Always pay attention to rain
patterns and adjust your fertilization schedule as
Leaves need to remain on the bushes till
late fall. However, during the summer leaves can
stay wet for long periods and with the high
temperatures leaf spot can become a big
problem. If leaves are heavily infected, plants
will typically drop most of their leaves in late
summer or early fall and this will decrease the
amount of flowers set for next year's harvest.
Scout your plants for signs of disease and then
take appropriate control measures. For control
of leaf spot use a strobilurin, such as Abound
and Cabrio, in a rotation with Bravo.
Usually insects are not a problem in
Central Florida on blueberries but some
growers had an insect problem in early
summer. The young foliage on their plants
was being eaten. If plants were small this
could be a big problem. Several types of
beetles may be responsible. Dr. Oscar
Liburd identified one type that several
It is the
larvae can eat
roots and the
adults do the
damage on the
foliage. Notice the notch in the leaf in the
picture. I would like to hear from you if
you had a problem with this.
A last note is to be careful working
out in the heat and humidity. Be cautious
of heat stress. Drink plenty of fluids and
take frequent breaks preferably in the
Be safe in the heat!
Hillsborough County Extension Service
813-744-5519, ext. 134
Early Season Disease
Jim Mertely and Natalia Peres
By now, most runner plants have
been ordered for the fall strawberry crop.
This is a good time to think about disease
management and the products needed to
get our strawberry plants off to a healthy
The first consideration is whether to
dip plants in fungicides before planting.
Dip treatments could have prevented
painful losses several years ago, when
nurseries had problems with the anthracnose
fungus Colletotrichum acutatum. Anthracnose-
infected transplants from these nurseries grew
poorly or died from extensive root infections (Fig
1). More recently, nursery owners have improved
their control of C. acutatum, thus removing the
main justification for pre-plant dips. Never-the-
less, it pays to be vigilant when dealing with this
pathogen. If dark, sunken lesions are found on
the petioles of some transplants (Fig. 2), bring
them to your county extension office or the UF
Plant Diagnostic Lab on County Road 672 to
determine the cause. Dip treatment with
Abound or Switch may be recommended if C.
acutatum is found. Transplants should be dipped
at recommended rates, and set as soon as possible
after treatment to avoid phytotoxicity.
Crown rots are another problem which
may strike unexpectedly. There are two principal
crown rot diseases, both of which first appear
after plant establishment in the fall. They are
Colletotrichum crown rot caused by C.
gloeosporioides, and Phytophthora crown rot
caused by several species of Phytophthora. The
symptoms are similar for each disease, i.e.,
reddish brown discoloration in the crown leading
to plant collapse and death (Figs. 3 & 4), but the
pathogens are distinctly different and are
controlled in different ways.
C. gloeosporioides survives on native
vegetation and infects young plants from the top.
During normal seasons, this pathogen is
controlled by routine applications of captain.
The roots of runner plants may be invaded
by Phytophthora species in the nursery. The
pathogen eventually enters the crown to cause a
typical crown rot in the production field. Last
season, many 'Sweet Charlie' and 'Carmine'
transplants were infected by Phytophthora,
including those planted at GCREC. When our
plants began dying, we injected Ridomil Gold
through the drip system, and sprayed the foliage
twice with potassium phosphite, which is
available under several brand names. These
aggressive actions illustrate two different
strategies for controlling Phytophthora crown rot.
Using them together after the plants begin
to collapse is fairly effective, but
expensive. Commercial growers should
consider a preventive treatment, that is,
deploy one product or the other by mid-
November, or as soon as the plants have
sufficient roots or foliage for absorption. If
the treatment is started before plants begin
to collapse, this one-product strategy
should provide good insurance against
Hopefully, early season anthracnose
and crown rots will not be severe this year.
However, early applications of broad- Fig. 2. Petiole lesions (C. acutatum)
spectrum fungicides such as captain or
thiram often result in higher yields and
better quality later in the season, even in
the absence of major diseases. Sprays
should begin as soon as the plants are
watered in, and continue on a regular
schedule throughout the season. Since
disease pressure is generally low during the
early season, low rates of captain or thiram
are adequate to protect the first crop.
However, higher rates may be necessary in
February and March as warmer Fig. 3. Crown rot discoloration
temperatures and spring rains increase
disease pressure on the main crop.
During certain times of the season,
standard applications of captain or thiram
can be replaced by or supplemented with
other products to better control powdery
mildew, Botrytis fruit rot, and anthracnose
fruit rot. Future issues of Berry/Vegetable
Times will carry articles about these
Fig. 4. Crown rotplant collapse
Fig. 1. Root necrosis The use of trade names in this publication is solely for the
(C. acutatum) purpose ofproviding specific information. It is not a
guarantee or warranty of the products names and does
not signify that they are approved to the exclusion of oth-
ers of suitable composition. Use pesticides safely. Read
and follow directions on the manufacturer's label
Abacus, Abba, Agri-Mek, and
Epi-Mek Have the Same Active
Jim Price and Curtis Nagle
Abamectin, active ingredient of
Agri-Mek (by Syngenta), has been a good
miticide for the Florida strawberry
industry. There was a period several years
ago though, when spider mites became
resistant to it because there were
insufficient rotational partners and
abamectin was overused. Since then
several good miticides (including
acequinocyl Kanemite, bifenazate
Acramite, etoxazol Zeal, hexythiazox
Savey and spiromesifen Oberon') have
been developed, registered, and rotated into
management schemes and abamectin has
become effective again. These days it
consistently performs well in miticide trials
at UF GCREC.
There is a chance now that
abamectin could become overused again
simply through growers' misunderstanding
the nature of some products newly
available. Epi-Mek abamectin (by
Syngenta) has appeared on the strawberry
pesticide market and recently a new
abamectin product, Abba (by Makhteshim
Agan of North America), has been
registered for spider mite control. Another
product, Abacus abamectin (by Rotam
USA, LLC), is nearing registration and
other abamectin products may be registered
in the intermediate future. Abacus',
Abba, Agri-Mek, and Epi-Mek are all
formulations of the same abamectin active
ingredient. The registered labels restrict
their use to 64 ounces per season but none
explain that, for resistance management
purposes, 64 ounces should be the total
abamectin product applied among all
Additionally, to reduce the chances
that the resistant spider mite form will
reappear, abamectin always should be applied
strictly according to label instructions which
include use of 16 ounce per acre. There never
should be more than four applications delivered
per season. These practices assure the most
complete elimination of resistant forms and
reduce the chances for selecting for resistance in
other spider mite generations that season. As
always, the above rotational partners should be
used after two abamectin applications separated
by 7-10 days.
Spider mites do not threaten the welfare of
the Florida strawberry industry today, but only
because the industry possesses excellent chemical
and biological tactics of management. It would
be a big loss if abamectin were overused again
and became unfit to carry its weight in spider mite
Representatives from GCREC and
FSGA visit New Zealand and Australia
Craig Chandler and Natalia Peres
Dr. Chip Hinton, Executive Director of
the Florida Strawberry Growers Association, and
Natalia Peres and Craig Chandler of GCREC
spent four days in New Zealand and 10 days in
Queensland Australia, visiting strawberry farms,
making presentations to groups of growers,
researchers, and industry reps, and working with
members of the Better Berries Team at the
Maroochy Research Station in Nambour. This
was done at the invitation of government
scientists in the two countries. Also, while in
Australia, Dr. Hinton, representing the Florida
Strawberry Research and Education Foundation
(a sister organization to FSGA), signed a five year
agreement with the Queensland Department of
Primary Industries and Forestry to collaborate in
raising funds to support research that is
considered important to both organizations.
Initially, funds will be used to conduct research
on diseases that affect transplant quality.
Photos on page 7.
i ne owner or the largest strawberry tarm in
New Zealand, Francie Perry, is on the far
left, along with her son-in-law and daughter,
Grant and Katie Perich.
Chip Hinton of the Florida Strawberry
Growers Association signs an agreement of
cooperation with Queensland government.
Two types of harvesting carts used on
many Australian strawberry farms.
Sunray Strawberry Farm's new truck. On the back it reads "You are following another
load of Yummy Queensland Strawberries".