Group Title: Berry/vegetable times.
Title: Berry/vegetable times. May 2003.
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Title: Berry/vegetable times. May 2003.
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: May 2003
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Bibliographic ID: UF00087388
Volume ID: VID00017
Source Institution: University of Florida
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SFLORIDA -Berry/Vegetable Times 0
I-.....u. ,o .^.d. &,,i .M ay 20031

In this issue

Spring Blueberry Growing Page 3

Cold Wintery Conditions and Page 3
the Impact on Thrips
Abundance in Blueberry
Potential Weed Host for Page 4
Tomato Spotted Wilt Virus in
Effect oflnterplanting Page 4
Secondary Crops on
Pesticide Registrations and Page 5

Miticide Trial Results Page 5

I ; 3ookfor Page 5
Growers, Others

Florida State Horticultural Page 5
Society Meeting CEU
Balm Update Page 5

at H ilsboroughCo i

Annua(IIl Meetl ing.-l k~'l

Oradilrda ii

Sting Nematode The
Scourge of Florida
J. W. Noling, J. L. Nance, and A.
J. Whidden
Edited by A. J. Whidden

The Problem
The sting nematode,
Belonolaimus longicaudatus, is the
most economically important
nematode pest of strawberry in
Florida. In most years it has only
caused sporadic problems but this past
season in the Plant City area
strawberry fields it caused significant
problems for many growers. Yields
reduced by the cool winter were
further reduced by sting nematode
damage. Also problems in the
rotation crops following the berries
are becoming apparent in the double
crops of tomato, green beans, bell
pepper, onions, cantaloupe and
squash. These crops are displaying
severe stunting and decline due to
sting nematode parasitism.

Nematode damage in a
pepper field.

As with strawberries the infested areas
consist of various sized spots but the
boundary is fairly well defined
between damaged and undamaged
plants. The degree of damage
expressed depends on the soil
population levels. Visible plant top

Tomatoes damaged by nematodes.
develops as a result of root damage
from nematode feeding. In general,
the roots of infected plants are unable
to p enetrate below the upper 3 to 4
inches of soil. Sting nematode feed
externally, particularly on root tips
which are killed, resulting in little or
no new root growth, plants lacking in
fine feeder roots, and the development
of short stubby branches formed from
the development of new lateral roots.
This produces a shallow root system
of coarse roots with knobby tips.

Why A Problem This Year?
It is likely sting nematode
was a greater problem this year
because soil and environmental
conditions played a very significant
role, as did farmer pest management
practices. During August and
September of 2002, when fields were
being fumigated, air temperatures for
these months were on average 5F
higher than the 30 year average for the
area and rainfall was only 15 to 25%
of the 30 year average for this time of
year. Hot and dry conditions favor
the rapid escape of soil fumigant
gases which likely translated to poorer
nematode control. Also the atypically
cool winter we had favored root and
nematode population growth rather
than foliage and fruit production.
In many fields there is the
presence of a compacted traffic
layer that restricts the diffusion of the
fumigant into deeper soil and this
likely played a significant role in the
loss of fumigation efficacy. Sting
nematodes are known to be at soil
(Continued on page 2)

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Volume III Issue 5

Berry/Vegetable Times

Volume III Issue 5 Berry/Vegetable Times

depths below 24 inches so it is
necessary to be able to get the
fumigant gases deep into the ground.
Although the impact of the
compaction layer on loss of fumigant
efficacy has yet to be field evaluated,
destruction of the compacted traffic
layer via chisel plow prior to
fumigation is highly recommended for
sting nematode infested fields this
coming season.

How to Resolve the Problem
Nematode management
should be viewed as a year-round
program requiring consideration of all
cultural, chemical and agronomic
practices within the areas where
strawberry plants will be grown.
Since there are currently no post plant
remediation measures available,
growers must insure the best
conditions (particularly soil moisture)
for soil fumigation in early fall. After
final harvest, all crops should be
destroyed as soon as possible to
remove nematode food sources; a
delay leads to greater nematode
populations and greater difficulty in
achieving control. Injection of water
soluble fumigant compounds through
the drip tube has been successfully
used to get rid of the crop and reduce
the sting population.
Sting nematode seem to be
very sensitive to sudden changes in
soil conditions such as rapid drying so
fallowing even for a short time,
especially when coupled with early
crop destruction, can give significant
and immediate reduction in nematode
numbers. To extend the fallow
period, it may be necessary to
frequently cultivate the field to
maintain a clean weed-free condition.
Many weeds, such as bermuda and
crabgrass as well as other native
plants, can support a large increase in
sting population so weeds must be
managed during the summer to
control nematode numbers.
An alternative to summer
fallowing is cover cropping with a
poor or non-host crop. Cover crop
rotations with American jointvetch,
hairy indigo, or showy crotalaria have
all been shown to reduce sting
nematode populations. Hairy indigo
(Indigofera hirsuta) and velvet bean
(Mucuna deeringiana), two vigorous
growing legumes, have been reported
to suppress sting and root-knot

nematode populations. Sorghum
sudangrass is a poor choice for sting
infested fields and iron clay pea has
been observed to increase sting
populations. To be effective, cover
crop stands should be established
quickly and kept as free as possible of
grasses and other undesirable host

Sting Nematode
Management Suggestions
Avoid methyl bromide
formulations with high
levels of chloropicrin since
the pic has only limited
nematicidal activity. Do not
compromise maximum
application rate per acre in
sting infested field areas.

Implement year-round weed
management practices
which minimize weed

Ensure chemical and/or
physical destruction of all
crop roots as early as
possible after final harvest
to minimize further increase
of nematode population.

Consider a summer weed
free, clean fallow.

Consider broadcast
application of Telone II, C-
17, or C-35, using deep
injection and effective soil
sealing systems (i.e. Yetter,
roller, surface water seal).
Do not rotovate or disturb
soil after fumigation, other
than to roll or surface water

Consider chisel plowing of
field to destroy compacted
traffic layer prior to soil

Green bean damage.

Obvious damage to onions.

Field of squash damage by

Cantaloupe field damage.

Volume III Issue 5

Berry/Vegetable Times

Volume III Issue 5 Berry/Vegetable Times

Spring Blueberry
Growing Tips
Alicia Whidden

Blueberries require acid
soils (pH 3.5-5.5) to grow well in
Florida. They are susceptible to iron
deficiency and iron is more available
at a lower pH. If iron deficiency
symptoms are seen, this could be a
sign that the soil pH is too high for
blueberries so check the soil pH to see
if it is in the proper range for good
growth. Foliar applications of iron
chelates can be sprayed until the pH
problem can be corrected.
Blueberry roots do not have
root hairs, therefore, they have a small
surface area to absorb nutrients and
are not very efficient. The roots are
very sensitive to waterlogged or dry
conditions. If mycorrhizae, which are
naturally occurring specialized fungi
associated with roots, are present the
nutrient uptake is improved. Roots
are sensitive to nitrate fertilizers and
chlorides. An ammonium source of
fertilizer should be used, such as
ammonium sulfate or urea; also do not
use muriate of potash (KC1) because
of the chloride content.
Blueberry plants have little
lateral translocation in the plant of
water and nutrients so the entire root
zone should be reached by the
irrigation system and fertilizer should
be evenly distributed over the entire
root zone. In Florida it is necessary to
fertilize more often than in other
states due to our long growing season,
heavy summer rains and the low
fertilizer-holding capacity of the soils
and bark used to grow blueberries.
Dr. Paul Lyrene recommends
fertilizing lightly 8 times per year-
approximately the first of each month
from February to September. Use a
NPK fertilizer plus magnesium and
the total amount of nitrogen applied
per acre for the year should not be less
than 1001b/acre/year; put out a fairly
equal amount of nitrogen in each
Southern highbush
blueberry plants are pruned to
stimulate vegetative growth for the
next crop and to adjust fruit load.
You can prune to adjust the fruit load
in late winter and through petal drop.
Pruning done as soon as the fruit
harvest is finished is to stimulate a

vegetative growth flush. This pruning
will produce the new growth that
forms flower buds for next year's crop
of fruit. It is important to have as
many leaves as possible and to keep
them on the bush through the fall to
produce a large amount of bloom for
next year. To retain the leaves on the
bush it is necessary to protect them
from fungal diseases and this will
require several fungicide applications
throughout the growing season.

Thanks to Dr. Paul Lyrenefor the
f, ,i- .l.. .... ,,i and reviewing
the article.

Cold Wintery
Conditions may have
Impacted Thrips
Abundance in Florida
Blueberries during 2003
Dr. Oscar Liburd, Entomology
and Nematology, Gainesville,
Florida. E. mail

Little is known about flower
thrips management with regards to
blueberry production in the
southeastern United States. In a
recent survey conducted by the
University of Florida Fruit and
Vegetable IPM Laboratory in
Gainesville, in cooperation with
several county extension agents,
Florida blueberry growers cited
flower thrips as their most important
insect pest that warrants management.
In general, flower thrips species have
a very short life cycle, approximately
18-22 days under ideal conditions,
and will complete multiple
generations per year. In Florida, the
Florida flower thrips, Frankliniella
bispinosa (Morgan), eastern flower
thrips, F. tritici (Fitch), and western
flower thrips F. occidentalis
(Pergrande) have been identified as

pests of both southern highbush and
rabbiteye blueberries. These three
species of flower thrips are known to
have a wide host range and cause
extensive damage on many different
crop plants. In north-central Florida,
the Florida Flower thrips appear to be
the dominant species in blueberries,
occurring in about 95% of our
samples. Thrips feed on ovary, style,
filaments and anthers, as well as
developing berries, which can
ultimately affect yield. During 2003,
growers in north central Florida
experienced fewer problems from
thrips damage compared with 2002.
We believe the primary reason for this
may be that the cold December and
January freeze resulted in a quick
bloom and delayed the emergence and
movement of thrips into commercial
blueberry fields. In Gainesville, by
the time thrips population was high
enough to cause economic damage the
bloom period was over. A similar less
dramatic situation occurred south-
central Florida. Populations of thrips
became high during mid bloom in
Haines City, subsequently posing less
threat to blueberry yields. Growers
in those areas who were using
insecticide tactics for managing thrips
apparently used less insecticide
sprays. In our spring insecticide
screening trials for thrips, the only
compound that performed well in
suppressing thrips population was
SurroundTM (kaolin clay).
SurroundTM is produced by Engelhard
Corporation in Iselin, New Jersey and
is available at selected agricultural
retail stores. SurroundTM is a white
powdery compound, which does not
kill the insect but apparently prevent
the insect from feeding on floral
organs. SurroundTM has been reported
to be compatible with most sprayers.
The mechanism in which SurroundTM
control thrips has not been fully
understood and needs further research.
However, it is important to note that
similar findings have been reported
for SurroundTM with respect to thrips
in other fruit crops. A more detailed
account of our thrips insecticide work
will be reported in the next issue of
the newsletter.

Volume III Issue 5

Berry/Vegetable Times

Volume III Issue 5 Berry/Vegetable Times

Potential Weed Host for
Tomato Spotted Wilt
Virus in Florida
Scott Adkins, Larry T. Markle &
Erin Rosskopf- USDA-ARS-
USHRL, Fort Pierce & Carly
Baker, FDACS-DPI, Gainesville
Edited by Alicia Whidden

As reported in a UF Pest
Alert, American black nightshade
(Solanum americanum) found in
a vegetable field in southeast
Florida was confirmed as having
tomato spotted wilt virus
(TSWV). Symptoms were most

noticeable on new growth.
American black nightshade is a
common weed in fields and could
possibly serve as a source of
TSWV for infection of the crop.
TSWV infects tomatoes, peppers
and a wide range of other
vegetables and ornamental crops.
The Solanaceae and Compositae
families have the largest number
of susceptible plant species. The
virus is transmitted by several
species of thrips, including the
western flower (Frankliniella
occidentalis) and tobacco thrips
(F. fusca). Only larval thrips can
acquire TSWV, but both larval and

adult thrips can transmit the virus in a
persistent, though often sporadic
fashion. TSWV replicates in the
thrips vector and the plant hosts. The
virus and vector are frequently spread
through transport of ornamentals and
vegetable transplants.
The extremely wide and
overlapping host range of the virus
and its thrips vector makes control
difficult. There are very few host
plant resistance genes and a large
number of weed and ornamental hosts
providing between crop virus
reservoirs which make the situation
more difficult. The use of virus-free
transplants is a necessity.

Effect of Interplanting
Secondary Crops on
Strawberry Yield
John Duval, GCREC-Dover

To increase the utility of
land preparation, existing plastic
mulch, and micro-irrigation,
secondary crops are planted in beds
with winter annual strawberries. This
practice allows for earlier harvesting
of the secondary crop. The effect of
these secondary crops on marketable
yield of strawberry has not been
thoroughly investigated. Planting
takes place up to 5-6 weeks before the
end of the strawberry production
season dependent on strawberry
variety. Common secondary crops are

squash, cantaloupe, pickles, and
A study was instituted that
examined the effect of interplanting
squash, cantaloupe, and pickles from
seed, and cantaloupe and pepper from
transplants, on yield of strawberry.
Plantings of secondary crops occurred
on 28 Feb., 7 Mar., 14 Mar., and 21
Mar., 2003 into a stand of 'Strawberry
Festival' strawberries spaced 15
inches apart in row and 12 inches
between rows. Treatments were
replicated 3 times. Fertilization was
increased from 0.75 lbs N/acre/day
(IFAS recommendation) to 0.83
lbs/N/acre/day, a 10% increase to
compensate for additional plants in
the field. Data was collected from the
time of planting the second crop into
the plots until the end of the harvest

period. Data was collected for
marketable yield, number of
marketable berries, and cull fruit until
31 Mar. 2003. Data was subjected to
ANOVA procedures using SAS
statistical software. No significant
differences were detected among
treatments (p<0.05) for yield (Fig. 1),
number of berries (Fig. 2) or number
of cull fruit (data not presented).
This data suggests that there
is no detriment to strawberry fruit
from the interplanting of strawberries
with squash, pickles, cantaloupes, or
pepper planted up to 31 days before
the end of fruit harvest. This is true
when the strawberry population of the
field has been maintained and no
plants removed for the planting of the
second crop.

Figure 1. Effect of interplanting on
marketable yield of strawberry

2- 3000
z 2000
S 1000

28- 7-Mar 14- 21-
Feb Mar Mar

Figure 2: Effect of interplanting four
second crops on number of marketable


28- 7-Mar 14- 21-
Feb Mar Mar

N Control U Cantaloupe from transplants M Control I Cantlou
o Cantaloupe from seed D Pepper 0 Cantaloupe from seed 0 Pepper
M Squash U Pickles U Squash M Pickles

pe from transplant

Volume III Issue 5

Berry/Vegetable Times

Volume III Issue 5 Berry/Vegetable Times

Pesticide Registrations
and Actions Chemically
Speaking April 2003

On March 18, the Florida
Department of Agriculture and
Consumer Services (FDACS) sent a
letter to Syngenta Crop Protection to
inform them that the Department had
accepted the Section 24(c) application
for the use of Fulfill (pymetrozine)
insecticide (EPA Reg. # 100-912) for
control of green peach aphid and potato
aphid, and suppression of whitefly in
tomato grown for transplant. The
Special Local Needs (SLN) number is
FL-030004. (FDACS letter of 3/18/03).
Based on work by IR-4,
tolerances have been obtained for the
use of herbicide Dual Magnum (S-
metolachlor) in or on grass forage (10
ppm), grass hay (0.2 ppm), spinach (0.5)
ppm), and tomato (0.1 ppm). (Federal
Register, 4/2/03).

Miticide Trial Results
Jim Price, GCREC-Bradenton

Curtis Nagle, John Hogue and
Jim Price experimented with several
miticides in the UF GCREC Dover
fields this season, and the data are in and
statistical work has been performed.
The results of these experiments will be
shared among sponsoring businesses,
EPA, and the agricultural industry in
general. In then end, there should be
additional miticides and better patterns
of use available to the strawberry
industry that will result in improved
mite management and profitability.
The most important points at
this time are that we have had very good
results from some experimental
miticides that are in the more advanced
stages of development including:

1. Valent's ovicidal Zeal
(etoxazole) whether alone or
in combination with Danitol
2. Gowan's Mesa(
(milbemectin) alone and in
combination with Savey
3. Nichino America's Fujimite"
(fenpyroximate) alone
4. Arvesta's TM-41301
(acequinocyl) alone
Each of these has been under testing at
GCREC Dover for two to several years
and it is very likely that Zeal and
Mesa will be available for growers this

next season under those names.
Fujimite and TM-41301 will not be
available until later; they likely will be
given other names.

The Strawberry

A Book for Growers,
Others-Norman Childers,
Ph.D., Editor

Dr. Norman Childer's newest
book is now available to the public.
This is a complete and concise book on
strawberry production, modern
plasticulture with annual cultivars,
matted row with perennial cultivars,
protected culture, marketing, foreign
production, diseases, and more. Color
photography enhances each chapter and
contributions from GCREC-Dover
faculty are included. To order your
copy, send check or money order for
$29 plus $6 postage and handling to:
Dr. Norman F. Childers Publications,
3906 NW 31st Place, Gainesville, FL
Phone: 888-501-8822

Florida State Horticultural

Society- CEU Day
IPM strategies for controlling
pests with a wide host range and
pesticide safety, laws, and
Jonathan H. Crane, Pres.,

As part of the 116th Annual
Meeting of the Florida State
Horticultural Society, Dr. Steve Sargent,
Florida State Horticultural Society
Program Chairman, is pleased to
announce a CEU program aimed at
anyone interested in controlling pests on
fruits, vegetables, ornamentals, and
landscapes and being updated on the
latest in pesticide safety, laws, and
regulations. Richard Tyson, Seminole
County Vegetable and Turf Extension
Agent put the program together.
Featured speakers include Entomologist
Lance Osborne, who will address the
audience on "Integrated pest
management strategies for controlling
pests with wide plant host ranges" and
Thomas Dean, Asst. Extension Scientist,
who will instruct the audience on

"General standards/core -safety, laws,
and regulations". This IPM/Core
workshop will be held on Monday, June
9th beginning at 8:00 AM and ending at
12:00 noon at the Sheraton World
Resort (10100 International Drive,
Orlando). CEUs will be offered for
holders of pesticide licenses, Certified
Crop Advisors, and FNGA Certified
Industry Professionals. This CEU Day
is part of the FSHS annual meeting,
which will be held from 8 to 10 June.
Early registration (before 8 June) is $50
per person and includes a one-day
(Monday, June 9) pass to attend the
CEU Day, the concurrent Master
Gardener Training Workshop, all FSHS
presentations, and the Industry
Reception that evening. Room rates at
the Sheraton are very reasonable at
$89/night (call 1-800-327-0363 for
reservations, mention FSHS). To learn
more about FSHS and this year's
Annual Meeting, visit our web site
( or better yet
come to our meeting!
(c:/fshs/promotion/press release 4.doc)

Balm Update
Craig Chandler, GCREC-Dover

An architectural firm from
Gainesville, Ponikvar & Associates, is
currently finalizing plans for roads,
parking areas, sidewalks, and out-
buildings at the research center site in
Balm. These buildings will include
housing for the farm manager, graduate
students, and visiting scientists; offices
for the farm manager and maintenance
supervisor; restrooms and a break area
for field staff; a garage for vehicle and
tractor maintenance; space for pesticide
storage and handling, growth chambers,
and rearing rooms; and pole barns for
the storage of tractors, sprayers, and
field implements. Ponikvar is also
working with a civil engineering firm
that is obtaining water permits and
designing irrigation and drainage
systems for the new site. The bidding
process will begin soon, and
construction should start sometime this

A monthly newsletter of the University of Florida Institute of Food
.. I...cation

Editor AliciaWhidden, Director MaryChernesky
Gulf CoastResearch andEducation Center-Dover
13138 Lewis Gallagher Road Dover, FL 33527
(813)744-6630 SC512-1160
http //strawberry fas ufl edu
Design and Layout Chrintine Cooley (cecooley@nmal ifas ufl edi)
Director JackRechcigl

Volume III Issue 5

Berry/Vegetable Times

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