Group Title: Berry/vegetable times.
Title: Berry/vegetable times. January 2005.
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Title: Berry/vegetable times. January 2005.
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, University of Florida
Publisher: Gulf Coast Research and Education Center, University of Florida
Place of Publication: Dover
Publication Date: January 2005
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Volume ID: VID00032
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January 2005

In this issue...
Market Outlook for Blueberries Page 2

Information from the BMP Page 2
Workshops held in Hillsborough
and Manatee Counties in
Molybdenum in Strawberries Page 3
Sugars, Vitamin C, and Page 3
Anthocyanin levels in Strawberry
Fruit Vary During the Season
Actara" Aphid and Whitefly Page 4
Insecticide Registered in
Pesticide Regulations and Actions/ Page 4
Pesticide Potpourri
How Colorful is Your Diet? Page 4

The Tumid Mite: A Pest of Page 5
The Flowers Are Coming: Be Page 6
SHEET-Angular Leaf Spot: A
Bacterial Disease in Strawberries
in Florida

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) 744-5519 SC 541-5772
Alicia Whidden, Editor Mary Chemesky, Director
Gulf Coast Research and Education Center
13138 Lewis Gallagher Road, Dover, FL 33527
(813) 744-6630 SC 512-1160
Chistine Cooley, Layout and Design
Jack Rechcigl, Director

From Your Extension
In this month's issue of the
Florida Market Bulletin there is an
article on the spring 2004 Florida
agricultural produce promotion
campaign called i'. i, c Grid". This
was the third year of a campaign to
promote Florida produce across the
country and into Canada. The
campaign was expanded in the third
year due to the success of the first
two campaigns. According to the
Florida Department of Agriculture
and Consumer Services (DACS) this
campaign has increased retail sales of
Florida produce. USDA statistics
report that Florida's agriculture
production value increased 4.7% in
2002. At the same time the eight
southern states of Alabama,
Arkansas, Georgia, Louisiana,
Mississippi, North and South
Carolina, and Texas as a group had
an 11.7% decline in their ag
production sector. For more
information check out the January
2005 Florida Market Bulletin.
The Florida Market Bulletin
is published monthly by DACS and
is free to Florida residents who
request it. DACS uses it to get
information to consumers. Also
there is a classified section where
you can find or advertise for sale ag-
related items that have been produced
or used on the farm. There is no
charge for putting an ad in the
Market Bulletin. Contact
information is: Florida AgLine 1-
888-816-6854 or www.florida-
February 7th will be Food
Checkout Day. It is estimated that

the average American will have
earned enough disposable income in
the first 37 days of the year to pay for
their food supply for the whole year.
It is estimated that only 10% of a
person's disposable income goes
toward food. We have one of the
best food supplies in the world. Not
only is it cheap but also one of the
safest in the world and with a great
diversity of products. US farmers
should be very proud of the job they

flqk& #I faZen
Hillsborough County Extension
Service 813-744-5519, ext.134

Alicia Whidden

In 2004 the University of
Florida Horticulture Department
started a new Florida Stone Fruit
Extension Program. As part of the
program a new on-line quarterly
newsletter, the Florida Peach
newsletter, has been created. It will
focus on peaches but will also have
the latest information on plums and
nectarines for the state. The first
edition of the newsletter came out in
December and can be found at http://

IFAS is an Equal Employment Opportunity Affirmative Action Employer authorized 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 Departmein of Agnculture, Cooperative Extension Service, University of Flonda, IFAS, Florida A & M
University Cooperative Extension Program, and Bloards of the County Commissioners Cooperating

January 2005

Berry/Vegetable Times

Berry/Vegetable Times

Market Outlook for Blueberries
Alicia Whidden

Blueberries have been touted as a great
"health" food. With the number of health food books
telling us to eat blueberries to have better health the
demand for the product should only increase.
Blueberries are native to North America and are one of
the few truly blue foods. North America produces 90%
of the world's production. The US and Canada are the
largest producers and consumers but worldwide demand
for blueberries is increasing. The harvest runs from
about April 1st to early October. The nation's 2004
highbush crop was approximately 269 million pounds
and 154 million of those were consumed fresh.
Christine Morris in The Fruit Growers News, Sparta,
Michigan quoted Mark Villata, executive director for
the U. S, Highbush Blueberry Council as saying the
demand for blueberries has convinced the West Coast to
plant more. There is strong domestic demand for the
fruit but the international demand continues to grow.
According to Vallata, Japan is the largest off-shore
market and South Korea looks to be next. Production of
blueberries is also increasing in South America. Chile
and Argentina are the largest exporters of blueberries to
the US. According to Morris' article, in 2003 the
average consumption in the US of highbush blueberries
both fresh and processed was about 17 ounces per
person. This was a 9% increase from 1999.

2004 Highbush Crop Estimate (millions of pounds).


2003 Fresh 2004 Fresh Percent (%)
and Process and Process Change

West 79.7 111 +39
Midwest 64 69 +8
Northeast 40.9 37.5 -8
South 46.3 51.4 +11
Total All 230.9 268.9 +16

Source: North American Blueberry Council

Information from the BMP
Workshops held in Hillsborough and
Manatee Counties in December
Vegetable and Agronomic Crop BMP Manual
Workshop Notes
Phyllis Gilreath and Alicia Whidden

The Best Management Practices (BMP)
Manual for Vegetable and Agronomic Crops was
developed to address agricultural nonpoint pollution
sources as originally mandated by the Federal Clean
Water Act back in 1972. More recently, Total
Maximum Daily Load (TMDL) guidelines have been a
driving force behind ensuring that growers are following
BMPs to reduce impacts to impaired water bodies.
Currently the draft BMP manual is 167 pages in length
and after 3 years of development and review, is
scheduled to be adopted by rule. The purpose of the
recent workshops was to give growers an opportunity to
provide input and feedback to FDACS, the lead agency
in development of the manual. What's in it for you?
Once adopted by rule, verified by FDEP and
implemented, growers who voluntarily sign up and
follow BMP guidelines will receive a "Presumption of
Compliance" with regards to state water quality
standards. Also, monetary assistance may be available
through cost share programs such as FARMS.
BMP implementation will rely upon a three-
pronged approach. There are 13 general or universal
BMPs that are applicable to many farming operations
(page 10 of the manual). By doing an inventory of
current farm practices, growers will find that they are
already following some of these baseline BMPs. You
do not have to do them all, but growers will be expected
to make a reasonable effort to implement as many as
practical. Think of these as Tier 1 guidelines.
Following this inventory, growers should turn to the
BMP Decision Tree Flowchart (pages 7 & 8) which will
take you to Tier 2 guidelines. These are more specific
BMPs applicable to different situations. For vegetable
growers in Central Florida, the two that would be most
applicable include the Plasticulture Farming and the
Seasonal/Temporary Farming Operations. The
Plasticulture Farming Performance Standard includes 2
pages of qualitative guidelines (beginning on page 133).
The Seasonal/Temporary Farming Guidelines begin on
page 137. Follow the flowchart until you reach the
blocks) that best describe your farming operation. The
implication here is that participating growers will
implement both the general or Tier 1 BMPs and the Tier
2 BMPs applicable to their situation.
The next step is an on-farm assessment using
(Continued on page 3)

January 2005

Berry/Vegetable Times

the checklist in appendix A-1. FDACS Ag-Teams may
be able to assist growers with these on-farm assessments
which are specific for vegetable growers. This is the
tool that growers would use to mitigate the risks from
practices such as "over-fertilization". BMP 33
(Optimum Fertilization Management/Application)
contains these guidelines. Obviously, as with most
programs these days, documentation and recordkeeping
will be important.
Growers are encouraged to take a look at the
manual which is available online at htt://
vegetable&agronomicCrops.pdf, paying particular
attention to the sections that would be applicable to
them. There is still time to comment. Call your
extension agent if you have comments or concerns and
we will pass your comments along to FDACS. Once
the manual has been adopted (anticipated date of
adoption is currently March, 2005), then growers can
sign-up electronically by completing a Notice of Intent
form. We will pass along more information as it
becomes available.

Molybdenum in Strawberries
John Duval

Molybdenum (Mo) is an essential element for
plant growth and is one of the elements regularly tested
for by tissue analysis. Mo is very important for the
proper physiologic use of nitrate in plants. Therefore,
Mo deficiency often appears as a nitrogen deficiency.
Deficiency usually occurs when soil temperatures are
low (< 45 F) and plants are still growing. Recently
several growers have noted very high levels of Mo in
their plants, around 12-18 ppm. As there is no known
level of toxicity for Mo, this does not pose a problem for
our berries. When the level of Mo has been found at
1500 ppm in tomato, an intense yellow color in the
leaves was found but no other symptoms. So, if you
find you have high levels of Mo in your strawberry
plants there is no cause for worry; your plants will be
just fine.

The use of trade names in this publication is
solely for the 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 others of
suitable composition. Use pesticides safely.
Read and follow directions on the
manufacturer's label.

Sugars, Vitamin C, and Anthocyanin
levels in Strawberry Fruit Vary
During the Season
Craig Chandler and Steve Talcott*

Strawberry fruit may look the same from
harvest to harvest, but the levels of important chemical
compounds within the cells of these fruit can change
dramatically over the course of the season. We
harvested fruit from 9 cultivars and 13 breeding
selections on January 23rd, 2003 and then again a month
later on February 27th. The fruit was analyzed for
soluble solids (which consists mostly of sugars) and
chemical compounds known to be strong antioxidants.
The study was repeated in 2004, with 5 cultivars and 4
In every case, both in 2003 and 2004, the fruit
harvested in January had higher levels of soluble solids
than the fruit harvested in February. For example,
'Festival' fruit harvested in January 2003 had an average
TSS (total soluble solids) of 10.5 % compared to 5.2%
for fruit harvested in February. A difference of this
magnitude probably has a significant effect on flavor:
the fruit with higher soluble solids being sweeter.
The pattern for vitamin C in 2003 was similar
to that for soluble solids. Fruit harvested in January had
higher levels of vitamin C than fruit harvested in
February, for all but one selection. But in 2004, the
vitamin C content of fruit harvested in January was
higher than that of fruit harvested in February for only 5
of the 9 genotypes tested. The Vitamin C levels in
February fruit of 'Festival' were 39% and 24% less than
in January fruit in 2003 and 2004 respectively. Similar
differences were obtained for 'Treasure', with February
fruit having 37% and 38% less vitamin C than January
fruit in 2003 and 2004 respectively.
The opposite pattern occurred with
anthocyanins, compounds that give fruit their red color,
and the most important class of antioxidants in
strawberries. Anthocyanins were at higher levels in
February fruit than January fruit, for all but one cultivar.
The anthocyanin level of February fruit of 'Festival' was
almost double that of January fruit in 2003, and over
two-thirds higher than that of January fruit in 2004.
Vitamin C and anthocyanins are both
antioxidants: the level of one appears to be decreasing as
the other is increasing. One conclusion that could be
drawn from our study is that later season fruit, in
general, is not as sweet as earlier season fruit, but the
total quantity of antioxidant compounds in fruit remains
high over time.
*Steve Talcott is an assistant professor in the Food Science
and Human Nutrition Department, University of Florida,

January 2005

Berry/Vegetable Times

Actara Aphid and Whitefly
Insecticide Registered in
Jim Price, Curtis Nagle and Silvia Rondon

Thiamethoxam formulated as Actara recently
has been registered by Syngenta Crop Protection, Inc. in
field-grown strawberries for control of aphids and
whiteflies. It cannot be used in the greenhouse or on
plants grown for use as transplants. Actara can be
applied as a spray at 1.5 to 3 ounces (aphids) or 3 to 4
ounces (whiteflies) per acre up to 3 days before harvest.
No more than 8 ounces can be used in each growing
season and 7 days must elapse between applications.
Actara carries the signal word "Caution" and a 12 hour
worker reentry interval.
Thiamethoxam is a systemic neonicotinoid as is
imidacloprid Admire registered last year by Bayer
Crop Science. Actara has the advantage that it can be
applied as a spray during the cropping season.
Actara is highly toxic to bees and precautions
should be taken to protect them. Labelling information
indicates that Actara generally is safe to beneficial,
but the degree of compatibility of this product with
Phytoseiulus persimilis predatory mites in strawberries
is not sufficiently understood yet.
Scientists at the Gulf Coast Research and
Education Center have worked with thiamethoxam over
many years of development and conclude that is an
effective material to control whiteflies and aphids. The
Florida strawberry industry is fortunate to have this
material now available to them.
At the time Actara was registered, another
formulation of thiamethoxam also was registered as
Platinunl for aphids and whiteflies in strawberries.
Platinunl bears the prohibitive restriction that it must
be applied to the soil bed and not within 50 days of

Pesticide Regulations and Actions

?? On August 12, the Florida Department of
Agriculture and Consumer Services issued the
special local needs registration SLN FL-040006 to
Syngenta Crop Protection for the use of
pymetrozine (FulFill Ri insecticide (EPA Reg.
#100-912) on tomato to manage whitefly.
Specifically, the number of applications has been
increased from two to four. (FDACS notice of

?? Based on a request by KIM-C1, time limited
tolerances have been approved for the plant growth
regulator forchlorfenuron. The tolerances for
blueberry and will expire 5/31/06. (Federal
Register, 8/11/04).
?? Based on a request by Bayer Crop Science and
Janssen Pharmaceutica, Inc., tolerances have been
approved for the pre- and post-harvest fungicide
pyrimethanil. This is an anilinopyrimidine
fungicide that is active against Botrytis spp.,
Venturia spp., Alternaria solani, Alternaria mali,
Sphaerotheca macularis, and Monilinia spp.
Tolerances of importance to Florida include citrus
(post-harvest), strawberry, tomato, and tuberous/
corm vegetables. (Federal Register, 8/26/04).
?? Bayer CropScience has proposed to the EPA to
delete the usage on blueberry from their iprodione
(Rovral) product labels. (Agricultural Chemical
News, 8/15/04).
?? Syngenta has added suppression of black rot in cole
crops to their Actigard (acibenzolar) label.
(Agricultural Chemical News, 8/15/04).

Pesticide Potpourri

?? A nematode that had until recently been referred to
as race 3 of root knot has been classified as its own
species, Meloidogynefloridensis. An international
team of USDA and French scientists collaborated
on the placement of this new species. It was
originally isolated from root knot resistant peach
rootstocks in Gainesville, FL. These rootstocks are
the only known hosts as of now. (USDA ARS,

How Colorful is Your Diet?
Consumer Reports on Health

Eating your greens every day is not enough. According
to the National Cancer Institute, people should eat at
least one item from the five color group daily, the reds,
white, blues/purples, yellows and greens. That advice
stems from studies showing that different-colored
produce contains different phytochemicals, including

antioxidants and other disease-fighting substances.
Below is a list of the possible benefits of the
phytochemicals in fruits and vegetables of different
colors. For additional information, go to

(Continued on page 5)

January 2005

Berry/Vegetable Times

Phytochemical: Lycopene andAnthocyanins
Red fruit or vegetable: Lycopene-guava, pink
grapefuirt, tomatoes, and watermelon.
Anthocyanins- beets, cranberries, kidney beans,
raspberries, red applies, red cabbage, red onions,
strawberries, and cherries.
Possible Benefits: Lycopene-reduced prostate cancer
risk. Anthocyanins-lowered blood pressure; protection
against circulatory problems caused by diabetes.

Phytochemical: Allicin
White fruit or vegetable: Garlic, leeks, and white
Possible Benefits: reduced risk of cancer spread and
heart attack, lowered cholesterol and blood pressure;
enhanced infection defenses.

Phytochemical: Anthocyanins and Phenolics
Blue/Purple fruit or vegetable: Anthocyanins-black
berries, black currants, blueberries,
elderberries, purple grapes.
Phenolics-eggplant, plums, prunes, and raisins.
Possible Benefits: Anthocyanins-reduced risk of
cancer, heart disease, and age-related memory loss.
Phenolics-slowing of some effects of aging.

Phytochemical: Beta-carotene and Bioflavonoids
Yellow fruit or vegetable: Beta-carotene apricots,
butternut squash, cantaloupe, carrots, mangos, peaches,
pumpkin, and sweet potatoes. Bioflavonoids-apricots,
clementines, grapefruit, lemons, nectarines, oranges,
papaya, peaches, pears, pineapple, tangerines, yellow
peppers, and yellow raisins.
Possible Benefits: Beta-carotene reduced risk of
cancer and heart disease; maintenance of good vision;
increased infection fighting ability. Bioflavonoids -
together with the Vitamin C in these fruits, reduced
cancer and heart-attack risk; maintenance of healthy
skin, bones, and teeth.

Phytochemical: Lutein and Indoles
Green fruit or vegetables: Lutein-broccoli, green peas,
honeydew melon, kale, kiwifruit, leafy greens, romaine
lettuce, spinach. Indoles-arugula, broccoli, brussel
sprouts, cabbage, cauliflower, kale, rutabaga, Swiss
chard, turnips, watercress.
Possible Benefits: Lutein-maintenance of good vision;
reduced risk of macular degeneration and cataracts.
Indoles-reduced risk of breast and prostate cancer.

The Tumid Mite: A Pest of
Silvia Rondon and James Price

The tumid spider mite or tumid mite,
Tetranychus tumidus Banks, is dark red to purplish and
rather robust mite that can be found on the strawberry
crop throughout Florida (Fig. 1). The injury inflicted to
strawberry plants resembles the damage caused by the
twospotted spider mite (Tetranychus urticae Koch)
(Fig. 2). This injury appears as russeting of the lower
surface of leaves and in severe cases, discoloration to
the upper surface. The tumid mite and the twospotted
spider mite co-exist in the strawberry crop, and
particularly this year, the presence of the tumid mite has
been unusually high on some local farms. In some
instances, tumid mite densities have been higher than
densities of the twospotted spider mite.
Control of this pest is somewhat easier to
accomplish than is that of the twospotted spider mite. In
general, miticides that control twospotted spider mite
will control the tumid mite. Some broad-spectrum
insecticides, such as methomyl, kill the tumid mite but
do not control twospotted spider mite. Accordingly,
applications of such broad-spectrum insecticides may
render the tumid mite unnoticeable. Since the two
species are competitors for the same plant resources, the
twospotted spider mite may gain an advantage in the
strawberry crop when insecticides remove the tumid
mite. Currently, researchers at the University of Florida
are conducting trials to investigate the predatory mites
Phytoseiulus persimilis and Neoseiulus californicus for
control of the tumid mite.
Hosts. The tumid mite is a polyphagous spider
mite with over 70 host plants of various families such as
(Graminaceae, Leguminoseae, Compositae and
Malvaceae). It is a serious pest of cotton, celery, beans,
eggplant, beets, okra, peas, and sweet potato. It also
lives on hyacinth, castor bean, dahlia, morning glory,
palms, milkweed, mint, avocado, and other ornamental
and tropical plants.
Distribution. The tumid mite has been
reported in Georgia, Tennessee, South Carolina,
Louisiana, Texas, Hawaii, Arizona, and California.
Outside the continental U.S.A. it is known in Brazil,
Mexico, Puerto Rico, Guam and Trinidad and Tobago
(Saba. 1973. Life cycle and population dynamics of
Tetranychus tumidus (Acarina: Tetranychidae) in
Florida. Fla. Entomol. 57: 47-63).
Development. Female adults lay reddish or
whitish eggs on lower leaf surfaces. As a result, eggs of
both colors can be found on the same leaf, complicating
distinctions between tumid eggs and the whitish
twospotted spider mite eggs. As rule of thumb, the
(Continued on page 6)

January 2005

Berry/Vegetable Times

warmer it is, the more prolific the females become. Fe-
males can live for over 1 week at 75-840F (24-290C) and
for over 2 weeks at 66F (190C).
Monitoring. Procedures similar to those used
to detect twospotted spider mites should be followed to
monitor the tumid mite. In each block of plants (i.e, a
group of plant of the same variety from the same nursery
and planted on the same day) examine weekly, with the
aid of a 5x lens, the undersurface of 100 leaflets More
detail can be gained when needed by using a second
14X lens. No action threshold has been determined yet
for this mite, but an informal miticide action threshold
of about 5% if the leaflets possessing one or more tumid
and/or twospotted spider mite is good. As usual, scout-
ing should start as soon as transplant establishment irri-
gation ends.
Tumid mites can be damaging in Florida straw-
berries and attention must be given to them. Since con-
trol of this pest is normally reliable with available tools,
losses to this pest mite should remain low.
For more information visit hI ii 1I1.0. Iv!r-.
entomolo g/spidermites.htm

Fig. 1. Adult and egg stage of the tumid mite. The adult
is a robust red mite (0.1 mm), with prominent hairs
around the body which are visible with the aid of a 14X
lens. Credit Univ. of Georgia.

The Flowers Are Coming: Be Ready
Jim Mertely and Natalia Peres

In west central Florida, strawberries usually
start their main bloom in late January. During early to
mid-February, flowering is heavy and the final crop is
set. These are critical times for plant disease manage-
ment. Strawberry flowers are easily infected by Botrytis
cinerea (the cause of Botrytis fruit rot or gray mold) and
Colletotrichum acutatum (the cause of anthracnose fruit
rot). For this reason, timely applications of fungicides
during the main bloom period are essential for a healthy
During the early season, Captan and Thiram are
used regularly for general disease control. These appli-
cations should be continue during the main bloom pe-
riod, but additional fungicides may be needed. The
choice of what fungicide(s) to apply depends on the cul-
tivar grown and the diseases present. If Camarosa, Fes-
tival, Treasure, or Ventana are being grown, fungicides
such as Abound, Cabrio, Pristine, or Switch may be
needed to control anthracnose disease. If Carmine, Flor-
ida 39, or Sweet Charlie are being grown, Botrytis is the
main target, and can be controlled by Captevate or
Thiram. Pristine and Switch are also effective against
Botrytis. Captan, one of the ingredients of Captevate,
also suppresses anthracnose. Fields should be moni-
tored closely this time of year so that the bloom period
disease control program is started on time. Many fungi-
cide labels advise starting at "10% bloom". At this
stage, the average plant has one to two fully opened
flowers. Plan ahead and start on time!
To avoid the development of fungicide resis-
tance, products such as Abound, Cabrio, and Pristine
should not be applied more than four or five times per
season and no more than two sequential applications
should be made. Always follow product label and do
not go over the limit per season or the limit of consecu-
tive applications.

Fig. 2. The twospotted spider mite (0.07mm length).
Recognized by the two characteristic spots in the upper
surface. Arrow shows the feeding damage on the leaf
Credits. S.I.Rondon, IFAS, UF.

January 2005

Berry/Vegetable Times

Angular Leaf Spot: A Bacterial
Disease in Strawberries in Florida
Natalia Peres, Silvia Rondon, James Price, and
Daniel Cantliffe
Contacts: naperes(,,
srondon(,, iprice(,

Angular Leaf Spot (ALS) is a bacterial disease
caused by Xanthomonasfragariae Kennedy & King, a
pathogen highly specific to wild and cultivated
strawberry (Legard et. al. 2003). ALS is an important
disease on winter strawberry production worldwide. In
the U.S., it ranks 6th in economic importance after gray
mold (Botrytis cinerea L.), verticillium wilt (Verticillium
alboatrum Reinke & Berth), powdery mildew
(Sphaerotheca macularis L.), anthracnose
(Colletotrichum spp.), and pythium root rot (Pythium
spp.) (Sorensen et. al 1997). The rapid spread of ALS is
associated with the increasing rate of interchange of
plant material.
AL S was first reported in Minnesota in 1960
and since then it has been found in almost all cultivated
strawberry areas in the U.S. (Funt et. al. 1997). In
California, the largest U.S. producer of fresh
strawberries, ALS is a minor disease that occurs
especially during rainy weather or when overhead
sprinkler irrigation is used (Strand 1993). ALS is the
only strawberry disease in Florida caused by a bacterium
(Howard et. al 1985). Little is known regarding the
epidemiology of ALS (Funt et. al. 1997; Mass 1998);
however, development of the disease is favored by
warm days (200C/680F) and cold nights (2-4C/ 36-
390F) (Howard et al. 1985).

X. fragariae, the causal agent of ALS, is a
slow-growing, Gram-negative bacterium that produces
water-soaked lesions on the lower leaf surfaces (Fig. 1).
Lesions begin as small and irregular spots on the
undersurface of the leaflets. When moisture is high on
the leaves, lesions ooze sticky droplets of bacteria
(Howard et al. 1985). As the disease develops, these
lesions enlarge and coaleses to form reddish-brown
spots, which later become necrotic (Fig. 2). A practical
way to recognize the disease is to place the leaves
against a source of background light where the
translucent spots can be seen (Fig. 3).
During severe epidemics, the pathogen also can
cause lesions on the calyx of fruit that are identical to
foliar lesions (Fig. 4) and. when severe, can make the
fruit unmarketable (Legard et al. 2003). The tissue with
older damage eventually dies and dries up giving leaves
a ragged appearance (Strand 1993).

Spread of the Disease.
The primary source of inoculum in a new field
is contaminated transplants (Mass 1998). Secondary
inoculum comes from bacteria that exude from lesions
under high moisture conditions. Bacteria can survive on
dry infested leaves and tissue buried in the soil for up to
1 year (Roberts et al. 1997; Strand 1993). The pathogen
can be spread easily by harvesting operations when wet
and cool conditions favor the production of bacterial
exudate. The pathogen also can be dispersed by rain
and overhead sprinkler irrigation. If the pathogen
invades the vascular system of the plant, the disease will
be difficult to control and affected plants may wilt and
die, although this is rarely seen in Florida

Control Methods
The best way to control ALS is to use
pathogen-free transplants. Hydrogen peroxide and
copper fungicides can provide effective control of the
disease in some instances, but low rates of copper
should be used since phytotoxicity has been documented
with repeated sprays. Growers should avoid harvesting
and moving equipment through infected fields when the
plants are wet. Overuse of surfactants (wetter-stickers)
should be avoided when the disease is present.
Minimizing the use of overhead sprinklers during plant
establishment and for freeze protection will also reduce
the spread of the disease.

Literature Cited
Funt, R.C., M.A. Ellis, and C. Welty. 1997. Midwest small fruit pest
management handbook. The Ohio State University. 196
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Continued on page 8

January 2005

Berry/Vegetable Times

Fig. 1. Water soaked lesions ofAngular LeafSpot. Fig. 3. Translucent spots ofAngular Leaf Spot.

Fig. 2. Reddish-brown spots ofAngular Leaf Spot. Fig. 4. Angular Leaf Spot lesions on the calyx.

January 2005

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