Group Title: Berry/vegetable times.
Title: Berry/vegetable times. April 2004.
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Title: Berry/vegetable times. April 2004.
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: April 2004
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Volume ID: VID00027
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Berry/Vegetable Times


j Emi AS A Ltir.I &J

In this issue...

Twenty-five Years of the North Page 2
American Strawberry Industry

Diaprepes Weevil Problem in Page 3
Strawberries at GCREC Dover

Summer Strategies for Page 4
Strawberry Disease Control

Early Crop Destruction of Page 4
Abandoned Strawberry Field
Wind Damage to Cucurbits Page 6

Update on GCREC Balm Page 6

A monthly newsletter of the University of Florida IFAS,
Gulf Coast Research and Education Center and Flonda
Cooperative Extension Service
Hillsborough County Cooperative Ext Service
5339 CR 579, Seffner, FL 33584
(813) 7445519 SC 541-5772
Alicia Whdden, Editor Mary Chernesky Director
Gulf Coast Research and EducationCenter
13138 Lewis Gallagher Road, Dover FL 33527
(813) 744-6630 SC 512-1160
Chnstine Cooley, Layout and Design
Jack Rechcigl, Director
http //gcrec ifas ufl edu
http //gcrec lfaS ufl edu

From Your Extension
Agent...Afi&&a #Widden

As the strawberry season
winds down, the 2004 blueberry and
spring vegetable harvest is gearing
up. I want to mention a few prob-
lems to be on the lookout for in these
commodities, especially since we
had rainy windy weather in mid-
Thrips: One major concern
we have had recently is the heavy
thrips outbreak in the vegetable in-
dustry. It was feared we had a new
type of thrips, such as Thrips palmi,
which could be a major problem for
us. Dr. Dak Seal of the Tropical
Research and Education Center at
Homestead who is an expert on
Thrips palmi visited the area on
Sunday, April 18 to check out the
problem we have been having. Ac-
cording to Dr. Seal we do not have
T. palmi but we do have Western
Flower thrips, Frankliniella occiden-
talis. We normally have flower
thrips but this year the numbers are
much higher. Dr. Seal does not be-
lieve the thrips will cause much
damage but if you have high num-
bers and want to spray he recom-
mends Spintor at the 7-8 oz. rate
and if numbers of thrips are still high
after 7-10 days you can spray Lan-
nate. We are very lucky this is not T.
palmi since they are more devastat-
ing than flower thrips because they
feed on the foliage as well as flow-
ers. We are very grateful to Dr. Seal
for making the long trip up here es-
pecially on a Sunday to help us with
this problem in our fields.
Blueberries: Be on the

watch for anthracnose fruit rot (ripe
rot). The causal agent can be Colle-
totrichum gloeosporioides or C. acu-
tatum. For those of you who grow
strawberries these will be all too
familiar to you. The rot develops as
the fruit ripen. The blossom end of
the fruit becomes soft and may be
slightly sunken and usually you can
see masses of salmon colored spores
in the lesion. Fungicides that can be
used for this are Captan, Abound and
Another blueberry disease
to watch for is Botryosphaeria stem
blight. This is caused by Botryos-
phaeria dothidea. This is a dieback
disease and early symptoms are a
yellowing and reddening of the
leaves on 1 or a few branches. In
most cases one branch will die and
the rest of the bush will be fine. In-
fection is mostly through wounds.
When the plants are producing lush
tender growth in the spring and be-
come infected the dieback can occur
very quickly. There is no fungicide
registered for this but it is considered
to be good practice to apply a fungi-
cide after pruning and to watch for
leaf spot diseases in the summer and
apply fungicides as needed to keep
as many healthy leaves on the plant
as possible to maximize plant vigor.
Cucurbits: Be on the look-
out for downy mildew, powdery mil-
dew, and gummy stem blight.
Downy mildew appears as small
chlorotic or yellowish areas on the
upper leaf surface and can become
brown and form dead patches. Le-
sions can grow together and become
so large the entire leaf dies which

(Continued on page 2)

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function without regard to race, color, sex, age, handicap, or national origin U S Departmein of Agnculture, Cooperative Extension Service, University of Flonda, IFAS, Florida A & M
University Cooperative Extension Program, and EBoards of the County Commissioners Cooperating

Berry/Vegetable Times

April/May 2004


Volume IV Issue 4/5

Berry/Vegetable Times

can lead to sunscald on the fruit.
Powdery mildew forms white fuzzy
patches on both the upper and lower
surfaces of leaves. Gummy stem
blight can affect the leaves and stem.
The most characteristic symptom is
that the stem cankers can exude a
brown to reddish brown gummy liq-
uid. The plant can be killed and if
fruit is infected there can be a rapid
decay of the interior of the fruit.
There is a wide range of
products listed for these diseases.
Read the fungicide label to be sure
the type of cucurbit you are growing
and the disease you want to control
is on the product label. The manex,
manzate, dithane formulations gen-
erally list downy mildew and gummy
stem blight. The chlorothalonil prod-
ucts such as Equus, Echo, and Bravo
and the strobulurins, such as Amistar
and Cabrio, and the combination
product, Pristine, list downy mil-
dew, powdery mildew and gummy
stem blight. Ridomil and Aliette
have downy mildew listed on their
labels. Flint, sulfur and Nova are
registered for powdery mildew.
This is just a quick list of
potential problems for you to be
aware of. If I can be of any help
please call me at the Extension office
at 813-744-5519, ext. 134.

Twenty-five Years
of the North American
Strawberry Industry
Tom Sjulin, Director of Strawberry
Production and Research for Driscoll
Strawberry Associates, Inc., Watson-
ville, California

The following article fo-
cuses on industry developments in
the past 25 years, and gives a per-
sonal view of what I expect for the
next 25 years.
The California strawberry
industry has strengthened its grip on
the North American industry in the
past 25 years. In 1978, California

produced 76% of the total US pro-
duction, Florida produced 5%, and
the rest of the US's share was 18%.
Last year, California's share of the
total was 88%, Florida was 8%, and
the rest of the US was 4%. During
this same period, total US production
tripled from 659 million pounds to
2.1 billion pounds. The production
value of the crop has grown even
faster, from $209 million in 1978 to
$1.33 billion in 2003.
Several factors have con-
tributed to California's increasing
domination of the North American
strawberry industry. Acreages have
increased in California and Florida,
while those in other states have de-
clined. Yields have continued to
climb over the past 25 years through
improved varieties and production
practices. Fresh market quality has
also improved during this period,
with some varieties combining large,
attractive fruit with high flavor and
good shelf life. Finally, new produc-
tion systems combined with new
genetics has allowed the California
industry to spread its increased pro-
duction across more weeks of the
year without dramatically increasing
peak volumes. These factors have
helped offset declining grower mar-
gins, which have resulted in lower
prices per pound on an inflation-
adjusted basis.
The increased yields in
California during the past 25 years
cannot be attributed to soil fumiga-
tion, as methyl bromide-chloropicrin
soil fumigation was a standard prac-
tice at the start of this period. Im-
proved irrigation and fertilization
practices, improved pest and disease
control and improved varieties have
all contributed to the yield improve-
ment. Adoption of day-neutral va-
rieties along the central coast of
California has extended the flower
initiation period, thus giving higher
yields. New varieties for southern
California are better adapted to early
planting through clear plastic mulch,
and have higher yields in the January
through March period.

Peak volumes in California
have declined as a percent of total
annual volumes from about 10% in
the peak week to 5 to 6%. This is
due to a combination of the earlier
harvests in southern California, the
widespread adoption of later-fruiting
day-neutral varieties in the central
coast districts, and the development
of significant late-fall to early -winter
production from summer-planted
day-neutral varieties in southern
California. This spreading of the
production curve across more weeks
of the year has resulted in more or-
derly marketing of the increased
volume, and helped maintain shelf
space in the produce market.
Florida has improved yields
over the past 25 years, although the
past three years have been affected
by unfavorable weather. The Univ.
of Florida breeding program led by
Craig Chandler has turned out a suc-
cession of better varieties, growers
have improved soil preparation, fer-
tilization and irrigation practices, and
planting stock is now grown rela-
tively free of infection by anthrac-
nose, a serious disease that impacts
both plant health and fruit produc-
The Future of the North
American Strawberry Industry.
One thing is certain, the North
American strawberry industry will
face its share of challenges but will
continue to grow and prosper for
quite some time to come. Helping
drive this expansion is an aging
North American population that is
more concerned about eating right,
and the explosion of research under-
scoring the health benefits of small
fruit consumption. Consumers will
be looking for fresh berries all year,
so I expect that shipments outside
the traditional peak months will in-
crease more rapidly.
Central Mexico will obvi-
ously increase in importance as a
supplier of fresh berries to North
America in the winter. Signs of that
abound in Central Mexico. When
(Continued on page 3)

Volume IV Issue 4/5

Berry/Vegetable Times

you drive into Los Reyes in the state
of Michoacan, international shippers
make offers to growers via bill-
boards; U.S. company names are
being hung on cooling facilities; and
new plantings of strawberries, rasp-
berries and blackberries are every-
where. Why Central Mexico? At
these higher elevations, it rarely
rains in the winter, the days are
sunny and warm but not too hot, and
the nights are cool and dry, all of
which is a great recipe for growing
berries. There is plenty of land, wa-
ter and labor, and truckloads of ber-
ries can reach a lot of the North
American population.
The Florida strawberry in-
dustry will be affected by Central
Mexico, and may even shrink in size.
But Florida is close to a lot of the
U.S. population and has strong
breeding programs. Their challenge
will be to stabilize production swings
during years of unstable weather.
They may have to follow the citrus
industry, and move south of Plant
The California strawberry
industry will face problems of land,
water and labor, but where else in
the world can you produce 100,000
pounds of strawberries per acre be-
tween March and November? Or
70,000 pounds per acre between
January and June? The high yields
per dollar input will keep California
in the driver's seat in the face of de-
clining grower margins, and the fruit
quality will continue to improve
through breeding and better manage-
ment. The strawberry industry will
continue to grow, even with some
year-to-year ups and downs.
In the face of what I've
presented, what can strawberry
growers do? The answer is to find
opportunity in the face of adversity.
Look at the changes in the North
American strawberry industry in the
past 25 years, and take advantage of
them. Consumers now eat fresh
strawberries all year around and they
show every sign of wanting more.
Twelve years ago, prices crashed

when the California industry shipped
more than a million trays a week in
early October; now we ship a million
or more trays a week nearly to the
end of October at profitable prices.
We've figured out ways to pick a lot
more strawberries in January through
March and July through December
without picking too many in April,
and the consumers have responded.
Sure, we don't sell many $30 trays
anymore, but who buys $30 straw-
berries? A few foolish people who
spend too much on dates, weddings
and anniversaries. People are getting
older, they are worried about what
they've been eating the past 30
years, and they want to eat more
fresh strawberries.
(This article was adaptedfrom a presentation
Dr. 5,,,'. : made at the 2004 North American
Conference, February 23-25, 2004, at
the Hilton Westshore in Tampa. The full
version ofDr. S,N'. :'s presentation, including
references and figures, can be viewed on the
GCREC-Dover web-site athtt://
strawberry. )

Diaprepes Weevil
Problem in Strawberries at
Jim Price, GCREC

Weevil larvae tentatively
identified as the Diaprepes root wee-
vil of citrus, killed more than 400
strawberry plants on the GCREC
Dover research farm this season.
The larvae were noticed in late Feb-
ruary, but likely had been present on
roots for some time. They may have
come from eggs laid by adult wee-
vils that had inhabited a nearby
small, un-kept citrus planting up-
rooted earlier for housing.
Weevils are snouted beetles
and Diaprepes weevil adults are
about 3% inch long, black with or-
ange, white or gray stripes. They
often fall to the ground when dis-
turbed. This species arrived in Flor-
ida in about 1964 from the Carib-
bean region and has not been previ-
ously reported from strawberry.

Additional information on the
Diaprepes weevil in Florida can be
found by reaching ht:// on the Internet and
entering "Diaprepes" as the re-
quested search term.

Fig. GCRECDoverfield

Affected plants at the
GCREC Dover farm first wilted,
then appeared to die from anthrac-
nose disease (Fig. 1). This similarity
may have prevented identification of
earlier infestations in the Plant City
area. The plants killed by the weevil
larvae had few roots (Fig. 2) and
would not adhere to the soil when
pulled by the gathered leaves, while
plants killed by anthracnose disease
held tightly to the soil. The more
recently killed and the wilting plants
oftentimes had 3% inch long white,
legless grubs (Fig. 3) that burrowed
from below and hollowed plant

Fig. 2 showing
lack of roots
due to weevil

Fig. 3 displaying
a legless, white

(Continued on page 4)

Volume IV Issue 4/5

Berry/Vegetable Times

Effective control measures
with current strawberry insecticides
may require label changes, so it is
important that growers avoid infesta-
tions until those changes are made.
Until then, any clearing activities in
infested citrus orchards near straw-
berry fields should occur well before

Summer Strategies for
Strawberry Disease
Jim Mertely, Teresa Seijo, Natalia

Crop destruction for the
control of strawberry diseases has
become more problematic with the
loss of paraquat for "burn-down" of
the old crop, and the new popularity
of double cropping. Nevertheless, it
is a good cultural practice that re-
duces the risk of anthracnose fruit rot
epidemics, and helps insure normal
yields in future berry crops.
Studies at the UF Straw-
berry Lab have shown that the an-
thracnose fungus Colletotrichum
acutatum easily survives on straw-
berry plants that are allowed to live
over the summer. However, when
the plants are killed and the crowns
are buried in the soil, the anthracnose
fungi infecting them soon die out
and are no longer detected on crowns
buried for 2 to 3 months. If there is
no second crop, a 6-month interval
between strawberry crops is more
than sufficient to plant a cover crop
and eliminate C. acutatum on old
strawberry debris. If a second crop
is planted, sufficient time is still
available to clean up and bare fallow
a field. This assumes that the old
strawberry crop is destroyed and
incorporated into the soil as soon as
When a second crop is
planted, old strawberry plants may
be physically removed after the last

harvest or as the new crop becomes
established. If a second pass is made
to kill volunteers sprouting from old
buried crowns, this practice is at
least as effective as herbicides, but
probably not as effective as fumi-
gants (e.g., K-Pam, Vapam). Rapid
destruction of the second crop is also
recommended, but more for sup-
pressing nematodes that feed on
both crops. Dr. Joe Noling will ad-
dress the topic of crop destruction
and nematode control in another
It is well known that C.
acutatum often enters our production
system on contaminated nursery
plants. So why put out the extra
effort and expense to destroy the old
strawberry crop? During this past
season, the number of anthracnose-
infected samples submitted to our
Diagnostic lab decreased strikingly
compared to 2001-02 and 2002-03.
This suggests that the nurseries in
California and/or Canada are making
progress in freeing their plant stocks
from C. acutatum. Another argu-
ment against crop destruction stems
from recent research showing that
strawberry isolates of C. acutatum
also survive on other crops and on
weeds. However, this study (based
on artificial inoculations in the green
house) also showed steady decreases
in populations over time. It is an
open question whether C. acutatum
persists on plants other than straw-
berry for meaningful lengths of time
in the field. Given these facts, the
possibility of infecting new straw-
berry crops with an over-summering
pathogen becomes more signifi-

The use of trade names in this pub-
lication 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.

cant... and is similar to shooting one-
self in the foot. Crop destruction is a
well-known practice that reduces the
survival of many diseases, nema-
todes, and insect pests between
Crop destruction, crop rota-
tion, rouging, and related cultural
practices have been used for centu-
ries to suppress plant diseases and
insect pests. The increased use of
pesticide sprays, chemical fumigants,
and increased cost of land and labor
have reduced our dependence on
these time-tested methods, especially
by producers of high-value specialty
crops. However, times are chang-
ing. For a myriad of reasons, famil-
iar pesticides are being lost or are
being increasingly restricted in their
use. Learning how to effectively
combine modern methods with well-
known cultural practices will be-
come increasingly important. It is a
good bet that more research and
more pest management activities will
be done under the IPM banner in the

Early Crop Destruction of
Abandoned Strawberry
J.W. Noling, Citrus REC
Alicia Whidden

We have observed that be-
ing a strawberry grower is a full time
job. The job as we know and under-
stand it does not end at the conclu-
sion of the strawberry picking sea-
son ,which is now over a month past.
The job is a full time responsibility,
because it requires a year- round
commitment to stewardship of the
land. As a full time job, many straw-
berry growers have elected to double
crop squash, cucumber, cantaloupe,
or eggplant among others following
the spring strawberry crop. If you
drive the area you also quickly dis-

Volume IV Issue 4/5

Berry/Vegetable Times

cover that other growers have opted as immediate as it should be to dis- each capable of incrementally reduc-
to simply turn the water and nutrition courage the practice. ing pest populations towards a col-
off to the crop and abandoned the lective, economically acceptable,
strawberry field to the elements. Fig- low level. IPM is now becoming a
ures 1,2, and 3 illustrate 3 different mandatory requirement for sting
nematode infested strawberry fields nematode management, since it is
abandoned after final strawberry becoming increasing clear that single
harvest in early March 2004. For the tactic approaches such as methyl
remainder of this article, we would bromide soil fumigation cannot pre-
like to discuss the ramifications of vent sting nematode problems from
field abandonment and for violating reoccurring within the field during
the early crop destruction principal .l the long production season. Since no
of Integrated Pest Management single tactic is perfect and complete,
(IPM). a number of tactics must be coupled
The sting nematode, Be- together. Lets assume that soil fumi-
lonolaimus longicaudatus, a pest we gation kills 95% of the nematode
are very familiar with, as are many population in soil. Killing 95% of a
growers in the Plant City area, is an soil population of 20 nematodes /
obligate parasite requiring living 100 cc soil leaves 1 nematode re-
plant root tissue to survive and grow. maining in soil, while killing 95% of
Without plant or pest controls, sting 2000 leaves a population of 100 per
populations will continue to grow as i. 100 cc soil. It should be obvious that
long as roots are made available as higher numbers generated during
food. The appearance of green foliar field abandonment, can ultimately
tissue within the abandon field ." translate to higher numbers surviving
(particularly after the recent rains) fumigation, which then accelerates
should remind growers that living the first appearance of nematode
roots continues to be made available problems in the field during the fall,
as food to sustain nematode popula- and for increasing overall strawberry
tion growth. The month long plus yield losses within the field.
delay in crop destruction could easily Growers may not be able to
translate into one or more additional completely eliminate the problem,
generations of nematodes with a but they can surely reduce soil den-
geometric increase in soil population Figure 1,2,3. Post season views of three sity and thus delay the time in which
density. When and if the plants do abandoned strawberry fields promoting the problem reappears within the
die, sting nematode is reputedly continued development and soil increase field. It should be clear that to avoid
ofsoilborne nematodes and other
known to migrate to deeper soil hori- disease ests. or minimize sting nematode prob-
zons to escape the inhospitable envi- lems, growers must do everything
ronment of surface soil. It is also they can to maintain sting popula-
well known that sting nematode is tions as low as possible during each
also capable of surviving for many ..stage of the annual crop production
months in soil in the absence of cycle.
food. In addition to nematodes, Clearly, the opportunity to
there are other soilborne disease enhance nematode control with fall
pests utilizing these food (roots) re- soil fumigation and minimize reoc-
sources being made available within curing losses in strawberry crop
the abandoned field and are as well yield due to nematodes begins with
adapted to survive to a subsequent early crop destruction after final har-
strawberry crop. As such, many dif- vest of each and every crop. For
ferent pest problems can be ampli- Figure 4. Use of a post season crop fields which are repeatedly problem-
fied during the field abandonment destruction chemical to kill strawberry atic with sting nematode, growers
plants, roots, and sting nematodes in
phase of strawberry production. In soil after final strawberry harvest. might also consider crop termination
this case, one of the main problems chemicals such as Vapam, Kpam,
with delaying crop destruction is that IPM is defined as the inte- Telone EC, or Telone Inline, applied
the consequence of the action is not gration of pest management tactics, at seasons end to kill strawberry

Volume IV Issue 4/5

Berry/Vegetable Times

roots and suppress sting nematode
populations. For these chemicals,
application rates of 10-20 gallons per
acre, applied in 100 to 150 gallons
water per 100 linear feet of row, has
been used effectively to kill plants,
roots, and sting nematode in soil
(Figure 4). As a minimum, the field
should be sprayed with Paraquat to
kill the foliage, and ultimately roots
of plants within rows.

Wind Damage to
John R. Duval

With persistent winds dur-
ing the month of March and first half
of April significant wind damage has
been noted at the GCREC and area
farms on cucurbit crops. Incessant
whipping of foliage and vines at the
soil lines have caused severe abra-
sions which has caused vine girdling
and vine damage. The most severe
damage has been observed in sum-
mer squash. Those plants which
were not wrung off at the mulch line
have developed long vertical cracks
along the vine. These can be so
severe as to give the vine the appear-
ance of a ribbon. While it is not
known how seriously this will affect
yield, it can be deduced that some
yield reduction will be evident as
well as increased incidence of dis-
eases which attack the vines of
plants (gummy stem blight and fusa-
rium wilt among others) through
wounds. Therefore, scouting for
disease will be more important for
timing of fungicidal sprays. In addi-
tion, damaged vines will be unable to
move water and nutrients as effec-
tively as undamaged vines so greater
monitoring of an effected field's
water status will be necessary. With
proper management, damaged vines
should be able to continue produc-
ing, albeit at lower levels.

GCREC Balm Update

Great progress has taken
place as construction continues at the
new Gulf Coast Research Center in
Balm. Amidst the activity at the
site, the exterior of the main building
is nearly complete as well as the
roadways throughout the center's
grounds. For continued updates

Tampa Bay Beekeepers
Honey Bee Seminar
Hillsborough Co. Extension Office
Seffner, FL
Saturday May 22, 2004
8:30 am to 3:30 pm
$15 (before May 13)
$20 (day of the event)
$5 each additional family member
Everything beginning beekeepers need to
know as well as advanced beekeeping tech-
niques. Lunch will be provided.
For registration information:
(813) 684-7814 or (813) 654-4705

Volume IV Issue 4/5

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