Group Title: Berry/vegetable times.
Title: Berry/vegetable times. September 2008.
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Title: Berry/vegetable times. September 2008.
Uniform Title: Berry/vegetable times.
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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: September 2008
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September 2008

Calendar of Events
Oct. 3 Kennco Field Day, Kennco
Manufacturing, Ruskin, 10:00-
4:00. CORE Bingo at 2:00 for 1
CORE. For more information and
to RSVP for the Bingo game, call

Oct. 14 & Nov. 12 Pesticide
License Testing. Hillsborough
County Extension Office, Seffner.
9 am. For more information call
Mary Beth Henry, 813-744-5519,
ext 103.

Nov. 5 Florida Ag Expo at
GCREC, Balm. 7:30 till 5:00. http://


Wednesday, November 5th
Call (813) 634-0000 or visit
for details.
Register your entire
team today!

A University of Florida/IFAS and Florida
Cooperative Extension Service newsletter
Hillsborough County, 5339 CR 579,
Seffner, FL 33584
(813) 744-5519 SC 541-5772
Joe Pergola, County Extension Director
Alicia Whidden, Editor
Gulf Coast Research & Education Center
14625 County Road 672,
Wimauma, FL 33598
(813) 634-0000 SC514-6890
Christine Cooley, Layout and Design
Craig K Chandler, Co-Editor
Jack Rechcigl, GCREC Center Director
http //gcrec ifas ufl edu

From Your Agent...
CORE Credits for Your Pesticide License

Growers who have Private Applicator Restricted Use
pesticide licenses need 4 CORE and 4 private applicator
CEUs ( continuing education units) every 4 years to renew
their license. The 4 CORE CEUs can be hard to get since
most grower meetings are given private applicator CEUs for
their program content but not CORE. The Bureau of
Compliance Monitoring, which makes the decisions on what
credits are given for programs, gives CORE credits for a very
strict set of topics that are listed in the CORE manual,
"Applying Pesticides Correctly".
If you are in need of CORE credits now or want to
start earning them for the next time you renew your license,
here are some ways you can earn CORE credits right now. I
will be doing a CORE Bingo game at the Kennco Field Day
on Oct. 3 from 2:00 to 3:00. This will be good for 1 CORE
credit. Kennco will be celebrating their 35th anniversary and
will be having a big party from 10:00 till 4:00. Their will be
food and drinks, vendors, demos and presentations. All are
(Continued on page 2)

EPA Reassessment of the Fumigants: New
Requirements for Buffer Zones
J.W. Noling and Alicia Whidden

Once finalized, a future outcome of the EPA Fumigant
Reregistration process will include the requirement for a
buffer zone surrounding fumigant treated fields. In general,
buffer zones are areas that must be maintained between the
outermost boundary of fumigant treated field and residential
property line of people living along the perimeter of the
treated field. According to EPA, buffer zones are defined as
areas, measured in perimeter distances around a fumigant
treated field, which are needed to ensure that airborne
concentrations of a fumigant compound do not encroach into
(Continued on page 2)

IFAS is an Equal Employment Opportunty-Affirmative Action Employer authonzed 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 ongin U S Department of Agriculture, Cooperative Extension Service, Umversity of Flonda, IFAS, Flonda A & M
University Cooperative Extension Program, and Boards of the County Commissioners Cooperating

September 2008

BerryNegetable Times

Berry/egetable Times

(Continued from page 1)
welcome but there is a RSVP for the CORE
Bingo. Call 1-800-645-2591 right away.
Another option for earning 1 CORE
credit that you need to take advantage of
very quickly is an article Phyllis Gilreath
wrote last October for Citrus & Vegetable
magazine. The way this works is you read
the article and then answer 10 questions on
the article and if you get a score of 70 or
higher you get 1 CORE point. Get in touch
with me and I can provide you the article and
the question set. I need the question set back
to me no later than Oct. 10 for you to be able
to get credit before the article expires in mid-
Mary Beth Henry, an Extension
Agent who handles pesticide testing at the
Extension office in Seffner, has a set of
videos you can watch to receive 1 CORE
credit. You will need to set up an
appointment with Mary Beth. She can be
reached at 813-744-5519, ext. 103. She also
has written on article for Ornamental
Outlook magazine which is good for 1
CORE. Contact her for a copy of her article
and question set and return the completed
questions to her.
Here are 4 ways for you to get CORE
credits that are required for your pesticide
renewal. Take advantage of some or all of
these CORE credit opportunities. Don't wait
until it is time to renew- there may not be
ways available for you to earn all the credits
you need on short notice. Take advantage of
the opportunities you have now!

813-744-5519, ext. 134

(Continued from page 1)
the adjacent property or exceed a specified
threshold concentration or dosage value of
human concern. Based on measurable
distance and regulatory requirement for
specific fumigant use, buffer zones thus
ultimately restrict where fumigant
treatments, relative to the residential property
line, or in some cases, occupied structure,
can legally occur.
At present only a few soil fumigant
products have buffer zone restrictions which
must be considered as a prerequisite for their
use. For example, all soil fumigants
containing 1,3-dichloropropene (Telone)
cannot be applied within 100 feet of an
occupied structure, such as a school, hospital,
business, or residence. If an occupied
structure does occur within the 100 ft buffer
zone, then the fumigation can proceed only if
"no person shall be present within the
structure at any time during the seven
consecutive day period following
application". With the fumigant
reassessment process nearing completion, it
appears that all of the remaining soil
fumigants undergoing reregistration
(Chloropicrin, Vapam, Kpam, Methyl iodide)
will also require buffer zone considerations
for their use. Like for Telone, EPA will
demand that no fumigant application will be
permitted within 0.25 miles of schools,
licensed day care centers, nursing homes,
assisted living facilities, hospitals, clinics or
prisons. More importantly, it would also
appear that buffer zone distances will be
measured to the property line and not to the
actual structure (as with Telone). This small
change will significantly increase overall
buffer zone impact in highly integrated urban
and agricultural areas such as Hillsborough
and West Palm Beach County.
Table 1 on page 4 attempts to
summarize buffer zone requirements for
typical chloropicrin use rates in a variety of
fruit and vegetable crops. As the table

September 2008

Berry/egetable Times

indicates, the actual size of the buffer zone
will be based upon field specific soil
application rates (lb/a), field acreage treated
(acres/day) and whether certain gas
impermeable plastic mulches (Hytibar,
Bromostop,etc.) are used to reduce fumigant
emissions from soil. For vegetable crops like
tomato and pepper, typically grown on wide
beds and row centers, Chloropicrin use rate is
generally less than 75 lb a.i. / acre (150 lb/
treated acre). At these per acre use rates,
buffer zones requirements only become a
significant issue when growers fumigant
significant acreage per day (ie., 40 acres per
day requiring al50 ft buffer). For strawberry
growers who may use as much as 100 lb of
chloropicrin per acre, buffer zones of more
than 200 feet will be required when treating
more than 20 acres per day. If growers are
willing to incur the additional cost for certain
virtually impermeable (VIF) plastic mulch
films, buffer zone distances could be
immediately reduced by 40 percent. If buffer
zones are still a problem after utilizing VIF
credit, the optimizing strategy to reduce buffer
zone impacts would be to treat only as many
acres along the field periphery as possible to
satisfy the current distance from treated field
location to residential property line. This
would suggest that growers would clearly
benefit from a planning and mapping process
which provides adjustments to treated acres
per day and for coordination of treatment
schedules and field locations to minimize
buffer zone impacts and distance
requirements. Clearly however, partitioning
fields and treatment schedules adds a new
level of complexity and management
expertise and other added costs resulting from
use inefficiencies of land, labor, and
equipment. These costs can be significant if
new equipment and labor crews have to be
frequently moved to satisfy treated acre per
day constraints.
Another strategy growers might adopt
to minimize buffer zone impact is to take

advantage of 25 ft buffer zone distances when
drip fumigation, rather than shank application,
is used as the means of fumigant delivery. All
of the specific EPA reassessments for the
different fumigants appear to indicate that
tarped drip irrigation applications, ie.,
chemigational approaches to soil fumigant
treatment rather than shank injections, are the
most efficient means in which to reduce
buffer zone requirement. Unfortunately, this
will also likely require changes to the design
and zoning of irrigation delivery to
accommodate treatment of appropriate field
areas. For seep irrigated fields, it is also
possible for growers to avoid significant
buffer zone impact by treating field
peripheries bounding residential property with
formulation of methyl iodide to take
advantage of shank applications to as much as
5 acres or more and buffer zones of as little as
25 feet.
In summary, Table 1 clearly shows
buffer zone requirements increase
dramatically with fumigant application rate,
the number of acres fumigated per day, and
when a LDPE plastic mulch is used rather
than one of the approved VIF mulch films. In
this regard, buffer zones are currently
regarded as an objectionable prerequisite to
fumigant use which growers must assume
responsibility for implementation. Not every
grower will be equally affected. In general,
the severity of the problem to a given grower
will be defined by the number and extent of
residential property bounding the fumigated
field border.
The entire process of fumigant
reregistration has been a long, multiphase
process and EPA is currently seeking
stakeholder comment and critique to their
final Human Health Risk Assessments for the
various fumigants. In response to EPA
fumigant reassessments, there is still
considerable grower concern that, if
mandated, buffer zone requirements will
significantly impact Florida growers,

September 2008

Berry/egetable Times

particularly strawberry growers and vegetable growers along the East Coast. We also think the
real impact from EPA reassessment of the fumigants goes well beyond buffer zones, with the
need for Fumigant Management Plans (FMP) (Figure 1) and air monitoring requirements for
field and buffer periphery, posting and notification, and for requirements for medical
certification, safety training, and fit testing to satisfy EPA respirator requirements when and if
needed in the field. In total, changes required to develop and implement the FMP will be
complex and comprehensive, adding a new burden of grower responsibility and liability. We
would encourage concerned growers to critically review the fumigant reassessment documents.
Copies of the assessments can be viewed and downloaded from the following website: http:// fumigants/#more We would also highly
recommend to those growers who object to these new restrictions, to submit, in writing, their
comments and concerns directly to EPA via the web address:
reregistration/soil fumigants/#comments or to contact representatives within Florida Farm
Bureau, Florida Strawberry Growers Association, Florida Tomato Exchange, or to Florida Fruit
and Vegetable Association. The deadline for the comment period is Oct. 30, 2008. It is very
important, especially for growers, to make comments. It is felt that EPA will take notice if a
large number of comments are received.

Table 1. Chloropicrin buffer zone distances (ft) based on per acre
use rates and numbers of acres treated per day (Block Size). Buffer
zone distances are interpolated from the EPA Fumigant Reassessment
published for Chloropicrin. To use the table, per acre use rates of
Chloropicrin (lb/a) must be determined as a percent of what the
grower will apply of the maximum broadcast (or treated acre) use
rate. For example, tomato growers typically apply 50% of the broad-
cast or treated acre rate (150 lb a.i./a) when the land is treated as
strips( 3 ft wide beds x 6 ft row centers).

Size Per Acre Use Rate of Chloropicrin (lb a.i./ acre)

65 70 75 80 85 90 95 100 105

1 25 25 25 25 25 25 25 25 25

5 25 25 25 25 25 29 36 43 50

10 43 50 57 64 71 79 86 93 100

20 46 50 71 93 114 143 179 214 250

30 60 70 107 144 181 221 264 307 350

40 86 100 150 200 250 296 339 382 425

Buffer zone distances above represent tarped bedded applications
without credits or use of buffer zone mitigating practices (ie., VIF
mulches). For example, field use of specific VIF mulch films will
provide a 40% reduction in the buffer zone distance represented

Figure 1.
Site-Specific Fumigant Management
Plans. Obligates Certified
applicators to verify and document
before proceeding:

General Site Info: Address, description,
map aerial photo, property lines,
surrounding structures, bus stops,
schools, day care etc.

Applicator Info: License numbers,
address, location & dates for completing
all require training programs and health/
safety certifications.

Authorized on-site personnel: Handler
names and training provided.
Good Agricultural Practices:
Measurement & Description of all
mandatory GAPS.

Buffer Zones: Calculations & rationale
for buffer zone distances, including
fumigant rates used, block size, credits,
start-stop time for buffer zones.

Respirators and other PPE: Verifications
that PPE requirements met, respirator
training, fit testing, medical certifications

Air Monitoring interior field and buffer
zone perimeter: When, where samples
acquired. Names, address of sampler.

Additional Items: Posting, Notification of
neighbors, Record keeping, Emergency
Hazard Communication Procedures

September 2008

Berry/Vegetable Times

Sap Beetle Relief Expected
Jim Price and Curtis Nagle

Sap beetles have been problematic in
strawberry production for many, many years
and have been a most acute problem since
Lannate (methomyl) insecticide was removed
from use in strawberries over a year ago. The
adult sap beetles fly into strawberry fields
from nearby orchards, woodlands, or fruit
crops where they and their offspring create
holes in strawberry fruit and sometimes
establish residence there.

The University of Florida GCREC in
Wimauma has performed the research support
for and the FSGA and FFVA have put
together the application for a Section 18
emergency exemption to use Rimon 0.83EC
(novaluron) (Chemtura Corporation) to
control sap beetles in strawberries. Rimon is
an insect growth regulator ("IGR") that
effectively stops the reproduction of sap
beetles and prevents accumulation of their
larvae in fruit.
Asian cockroaches, building up in the
Plant City strawberry production area over
about the last 20 years, also eat holes in
strawberry fruit similarly to sap beetles.
GCREC data reveal that Rimon insecticide
stops the reproduction of Asian cockroaches
If approval to use Rimon is granted, it
is expected to be available by the time sap
beetles become a big problem in February
2009. The label will restrict applications to a

maximum of three, so there will be a period of
discovering the most effective timing of the
insecticide. Additionally, GCREC workers
are examining adulticides to partner with the
IGR for most effective control.
The introduction of Rimon would
reduce reproduction and the overall load of
sap beetles and Asian cockroaches in
strawberry fields, reduce occurrence of
feeding holes in strawberry fruit, and reduce
infestations of sap beetle larvae in fruit.
Benefits to fresh market production and to the
late-season processing market would be

Whitefly-transmitted Viruses in
Gary Vallad, UF/IFAS GCREC, Wimauma
Crystal Snodgrass, UF/IFAS Manatee Co. Extension
Scott Adkins, USDA/ARS, Fort Pierce

While tomato growers are quite familiar with
the need to manage whitefly populations to
minimize the impact of viruses like Tomato
yellow leaf curl virus (TYLVC), now cucurbit
growers need to be vigilant as well. Several
new whitefly-transmitted viruses are now
present in Florida, and include Cucurbit
yellowing stunt disorder virus (CYSDV),
Squash vein yellowing virus (SqVYV), and
Cucurbit leaf crumple virus (CuLCrV). All
cucurbit crops are susceptible to these viruses
to varying degrees. However, these viruses
pose little, if any, threat to solanaceous crops,
such as tomato or pepper. An outbreak of
CYSDV and SqVYV was already identified
in early September in Manatee County. The
following photos and descriptions are meant
to aid in the recognition of some of the
disease symptoms associated with these
viruses. Growers are strongly encouraged to
submit suspect samples to a county extension
office for an accurate diagnosis, since some
symptoms can easily be confused with
nutritional disorders or other diseases.

September 2008

Berry/egetable Times

Cantaloupe infected with Cucurbityellow
stunting disorder virus (CYSDV):
Causes a range of symptoms in various
cucurbits including stunting, deformation of
leaves, interveinal chlorosis, leaf mottling
and spotting. Symptoms often start on older
leaves and then progress to the younger

Watermelon vine decline caused by
Squash vein yellowing virus (SqVYV):
Most severe in watermelon, causes a sudden
decline of the plant near harvest that includes
chlorosis and necrosis of the leaves, necrosis
and collapse of petioles, and ultimately a
collapse of the vine. Although fruit may
appear normal from the outside, the rind is
often found to be discolored (necrotic) when
cut and the flesh may have a bitter taste.

Summer squash infected with Cucurbit
leaf crumple virus (CuLCrV):
On squash, causes stunting of the plant and a
thickened distortion of the leaves that give
them a curled or crumpled appearance.
CuLCrV also causes an uneven ripening and
distortion of squash fruit, often giving them a
distinctive striped appearance.
Management of these viral diseases is
similar to the recommendations made for
TYLCV control in tomato, focusing on the
management of whitefly populations:
Start with healthy transplants free of
whitefly and virus.
Employ a whitefly management program
based on frequent scouting of crop
and a proper rotation of systemic
insecticides and insecticidal oils and
Use silver reflective mulch.

September 2008

Berry/Vegetable Times

Destroy crop residue immediately
following harvest.
Avoid planting new cucurbit crops near
older symptomatic crops.
Also be aware that mixed viral infections can
occur, which can have a big effect on
symptom development among the various
cucurbit crops.

Additional References:
Whidden, A., J. Polston, P. Gilreath, and S.
Adkins. Triple threat for cucurbits. The Vegetarian,
UF/IFAS Horticultural Sciences Department
Newsletter, December 2007, lhp \ \\ \\
Webb, S.E., F. Akad, T.W. Nyoike, O.E.
Liburd, and J.E. Polston. Whitefly-transmitted cucurbit
leaf crumple virus in Florida. EDIS, Fact Sheet ENY-

Controlling Powdery Mildew on
Jim Mertely and Natalia Peres

Powdery mildew, caused by the
fungus Podosphaera macularis, is one of the
first diseases that appear after strawberries are
planted. It is also the first disease that
requires adding additional fungicides to the
spray tank. Powdery mildew is a sporadic
problem that is damaging some seasons, but
not others. Disease severity depends on three
main factors: 1) presence of the fungus early
in the season, 2) susceptibility of the cultivar
being grown, and 3) the weather. Under
favorable conditions, P. macularis produces
millions of spores that germinate and infect
new leaves within 24 hours (Photo 1-left).
Thus, the disease can rapidly get out of
control and cause epidemics. Good disease
management depends on spotting the fungus
early and starting an appropriate spray
program without delay or routinely applying
protective sprays during periods favorable to
the disease.

Strawberry transplants are commonly
infected by powdery mildew, which is not
surprising given the dense plant populations
and summer growing conditions found in
most nurseries. Some spores and mycelium
are still living when the transplants arrive in
Florida, but they do not immediately cause an
outbreak. Unlike many other plant pathogens,
P. macularis is suppressed by water due to
rainfall or overhead watering during the
establishment period. After establishment,
disease development occurs during periods of
mild temperatures (60 80 F) and high
relative humidity (75-95%). These conditions
can occur anytime from October to mid-
December. Growers should be especially
vigilant during this period regardless of the
disease control strategy they follow.
Proactive growers apply powdery mildew
fungicide(s) on a 7- to 14 day schedule during
November and early December, whether or
not the disease is visible. These fungicides do
not include captain or thiram which are not
very effective against powdery mildew. A
variant on this strategy would be to apply
suitable fungicides during this period
whenever temperature and relative humidity
favor disease development. Those who apply
fungicides only when the disease is
discovered should scout their fields
frequently, looking for whitish fungal growth
on the undersides of the leaves (Photo 1-
right). Sometimes this growth is sparse and
hard to see, especially in 'Camarosa'.
Therefore the scout should also be alert for
the first signs of purpling and upward curling
of the leaves (Photo 2). Anyone trying to
control powdery mildew should keep in mind
that fungicides work best during early stages
of the disease when the number of spores is
relatively small and controllable.
For this season, the list of fungicides
available for powdery mildew control has
changed and grown. Nova, which contains
the active ingredient myclobutanil, has been
renamed Rally. Sonoma is a competing brand

September 2008

Berry/egetable Times

that also contains myclobutanil. Fungicides in
the same chemical class as myclobutanil (Rally
and Sonoma) include trifumizole (Procure), and
two brands of tetraconazole (Bumper and
Orbit). These products are mentioned as a
group since they have similar properties. All
are systemic fungicides with curative action,
which comes in handy if a grower is delayed in
starting his control program. All share a
common, single mode of action and, for this
reason, should be rotated with other fungicides
with different properties to counteract the
development of resistance. Rotation partners
include the strobilurin fungicides Abound,
Cabrio, and Pristine. In addition, powdery
mildew was recently added to the label of
Switch. Quintec, a new and effective product
with a different mode of action from other
powdery mildew products, also has been
labeled for strawberries. Quintec has a 12
month plant-back interval for crops not on the
label. Fortunately, peppers, and cucurbits with
non-edible peels such as cantaloupe, honeydew,
and watermelon have been added to the label
and may be planted immediately after
strawberry if Quintec is used.
Alternative products for powdery
mildew control include the bicarbonates
(Amicarb, Kaligreen, and Milstop), hydrogen
peroxide (Oxidate), sulfurs, oils, and potassium
silicate (Sil-Matrix). Care must be exercised
when using the sulfurs when temperatures
exceed 80 to 850. Oil-based products are
occasionally phytotoxic under Florida
conditions and may suppress plant growth.
Additional information on strawberry powdery
mildew and the products used to control it are
given in a fact sheet (
PP129) on the University of Florida's EDIS

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 of others of
suitable composition. Use pesticides safely. Read and
follow directions on the manufacturer's label.

Photo 1. Left: Fungal growth with chains of spores
(60X). Right:Fungal growth on lower leaf surface

Photo 2. Left: Leaf purpling. Right: Leaf curling.

Soil Fumigation with K-Pam:
Importance of Water Volumes and
Fumigant Concentration for
Nutsedge Control
Bielinski M. Santos
Gulf Coast Research and Education Center,
University of Florida

Background. The search for methyl
bromide (MBr) alternatives has been a vast
source of research during the last decade, in
which hundreds of trials have been
conducted statewide to examine different
combinations of soil fumigants in
polyethylene-mulched tomato, pepper,
strawberry, and cucurbits. Although, a great
deal of progress has been achieved in this
field, currently there is no single molecule

September 2008

Berry/egetable Times

to replace MBr. Instead, on-going research
focuses not only on certain fumigant and
herbicide active ingredients, but also on
application techniques and formulations to
improve efficacy on weeds.
Nutsedge species are the most
troublesome weeds to control in polyethylene-
mulched beds. Both purple and yellow nutsedge
(Cyperus spp.) have the ability to emerge
through the mulch films and cause yield and
quality losses. A great deal of research has been
conducted on tomato, where some important
alternatives are available. However, in other
vegetables and ornamentals, these alternatives
do not look as clear as for tomato. Examples of
these are the methyl isothiocyanate generators
dazomet, metam sodium, and metam potassium
(K-Pam). The first two molecules have been the
subject of extensive scrutiny with mixed results
on nutsedge control. Recently, various reports
have suggested improved K-Pam performance
on these weeds. However, K-Pam rates,
application techniques and formulations are
blamed for the inconsistent results on nutsedge.
Field research with drip-applied K-Pam has
focused on determining the most appropriate
water application volumes and flow rates,
injection rates, and concentrations for nutsedge
Water Application Volume and Flow.
Research plots were established at the GCREC
to determine the effect of water volumes and
flow levels of K-Pam on nutsedge control. For
these trials, 8 inch tall by 28 inch wide beds
were pressed and covered with low-density
polyethylene mulch. Two drip irrigation lines
with emitters every 12 inches were placed under
the plastic. A single K-Pam rate of 60 gal/acre
was injected with 1 (>>3000 ppm) and 2 acre-in/
acre (>>1500 ppm) of water. The flow rates were
0.22, 0.34, and 0.45 gal/min/100 ft within each
water volume. An untreated control was
included. Nutsedge was counted at 2, 10, and 15
weeks after treatment (WAT). The results
indicated that the application of K-Pam
improved nutsedge control at 2 WAT. However,

this effect disappeared at 10 WAT and
beyond. There were no differences among
these water flow levels and volumes,
indicating that speed of K-Pam injection did
not improve efficacy. This finding
suggested that K-Pam rates and
concentrations had to be studied more
closely to improve performance.
Application Rates. Field trials at the
GCREC were carried out as described
above. Application rates were: a) 30 gal/
acre applied with 0.5 acre-inch/acre of water
(>>3000 ppm); b) 60 gal/acre in 0.5 acre-
inch/acre of water (>>6000 ppm); c) 60 gal/
acre in 1 acre-inch/acre of water (>>3000
ppm); d) 120 gal/acre in 1 acre-inch/acre of
water (>>6000 ppm); e) 120 gal/acre in 2 acre
-inch/acre of water (>>3000 ppm); and f) 240
gal/acre applied with 2 acre-inch/acre of
water (>>6000 ppm). Nutsedge was counted
at 4 and 10 WAT. All the K-Pam treatments
improved nutsedge control with respect to
the untreated check. These trials confirmed
that water volume alone was not an
important factor to improve efficacy.
Instead, water volume and rate combined
played significant roles in the definition of
the concentrations applied in the field.
Those treatments with 6000 ppm, regardless
of the water volume and rate, had better
nutsedge control than those with 3000 ppm.
Concentration Levels. The effect of
K-Pam concentrations on nutsedge growth
was assessed using similar methodology as
explained previously. The applied
concentrations were 0, 2000, 3000, 4000,
5000, and 6000 ppm. Nutsedge densities
were determined at 4, 6, and 10 WAT. The
application of 2000 ppm caused a sharp
decrease on the weed population, followed
by slow density reductions thereafter
(Figure 1). At 4, 6 or 10 WAT, there were
no differences in efficacy between 5000 and
6000 ppm. This indicated that 5000 ppm
appeared to be the critical K-Pam
concentration to obtain nutsedge densities

September 2008

Berry/Vegetable Times

below 100 plants/10 ft row. The application of 3000 ppm had poor performance in the trials.
This concentration has been usually recommended based on 60 gal/acre of K-Pam applied with
1 acre-inch/acre of water. These trials consistently show that concentration is more important
than rates for effective nutsedge control with K-Pam.

-*- 4WAT

0 1000

-*- 6WAT

2000 3000

-A- 10WAT

4000 5000 6000

Metam potassium concentration (ppm)

Figure 1. Effect of metam potassium (K-Pam) concentrations on nutsedge densities (WAT= weeks after

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September 2008

Berry/egetable Times

Brazilian Strawberry
Symposium and
Workshop on
Colletotrichum Diseases
of Fruit Crops
Natalia Peres

At the beginning of August, Craig
Chandler and I went to Brazil to give
presentations at the Brazilian Strawberry
Symposium. The symposium was organized by
EMBRAPA (Brazil's equivalent to the USDA)
and was held in Pelotas in the state of Rio
Grande do Sul in southern Brazil. The meeting
was attended by about 250 people including
researchers, extension agents, consultants,
growers, and students from about 10 different
states in Brazil, Argentina and Uruguay. After
the symposium, the Brazilian representatives
for Viansa strawberry nursery of Argentina
served as our hosts to visit a couple of
strawberry growers in the area. One of those
growers has been very successful in producing
'Strawberry Festival' on a semi-hydroponic
system. In the past few years, 'Strawberry
Festival' has become one of the most popular
short day cultivars in the major strawberry
growing areas of Brazil. More information
about strawberry production in Brazil can be
found in the April 2007 issue of the BVT
Newsletter (
In the middle of August, I had the
opportunity to attend the International
Congress of Plant Pathology
(ICPP) which was held in
Torino, Italy. The meeting was
attended by about 1800 plant
pathologists from all over the
world and it was a great
opportunity to interact with researchers from
many different places. Dr. Pete Timmer (from
the UF-CREC, Lake Alfred) and I organized a
one-day workshop on Colletotrichum Diseases
of Fruit Crops prior to the general ICPP. The

workshop dealt with the species, populations
and control of diseases caused by the fungus
Colletotrichum on many crops such as
strawberries, blueberries, citrus, apples,
grapes, olives, almonds and tropical fruits.
About 40 investigators from many different
countries attended the workshop. The
principal talks were presented by invited
speakers from Costa Rica, Israel, New
Zealand, Spain and the U.S. (AR, CA, FL,
NC, and NJ). In addition, there were 12
contributed posters and short talks by experts
from other countries such as Belgium,
England, Norway and Australia. A booklet
was prepared in advance including summaries
of all the invited talks and abstracts of the
contributed posters. A CD is being prepared
of the written summaries and the PowerPoint
presentations and will be distributed to all the
participants as well as to others with interest
in the area that were unable to attend. More
importantly, the workshop served to stimulate
interesting discussions on the status of
knowledge on these diseases and hopefully
served to generate future collaborations
among researchers working on diseases
caused by Colletotrichum. The ICPP meeting
is only held every 4 years and, unfortunately,
it coincided with our Agritech meeting this
year. I apologize for missing Agritech and I
hope to make it up to you during our AgExpo
on November 5!

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September 2008

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