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Hillsborough County Extension Office Pesticide License Testing. Third Tuesday of each month starts at 9:00am. 5339 CR 579, Seffner. Bring a photo ID. September 25 and 26 Core and Private Applicator Training and Exams: Core 10am-12pm Sept. 25 Private 10am-12pm Sept. 26 Manatee County Extension Service, Palmetto, FL. Core Exam training and testing: http://core9-25-13.eventbrite.com/ Private Applicator Exam training and testing: http://private9-26-13.eventbrite.com/ Oct. 21-22 Florida Agriculture Financial Management Conference, Omni Orlando Resort at Champions Gate. For more info go to www.fafmc.org. Oct. 22 Farm Labor Supervisor CORE Training Program. 8-5, Bartow. $80. http://fls2013bartow.eventbrite.com.

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. Department of Agriculture, Cooperative Extension Service, University of Florida, IFAS, Florida A & M

University Cooperative Extension Program, and Boards of the County Commissioners Cooperating.

Berry/Vegetable Times September 2013

A University of Florida/IFAS and Florida

Cooperative Extension Service Newsletter

Alicia Whidden, Editor

Hillsborough County, 5339 CR 579

Seffner, FL 33584 (813) 744-5519

Jack Rechcigl, Center Director

Hugh A. Smith, Co-Editor

Christine Cooley, Layout and Design

Gulf Coast Research & Education Center

14625 County Road 672,

Wimauma, FL 33598 (813) 634-0000

http://gcrec.ifas.ufl.edu

SAVE THE DATE

Wednesday November 6, 2013

Register at www.floridaagexpo.com

From Your Agent … To start off the new growing season, I thought I would

review the requirements for getting and keeping a private applicator

restricted use pesticide license. If you need to get a license, you

must first pass two tests- the CORE and private applicator tests.

Study manuals are available for these tests and can be purchased

from the IFAS Bookstore -http://ifasbooks.ifas.ufl.edu/c-76-

pesticides-exam-study-materials.aspx or at times are available for

purchase at the Hillsborough County Extension Office. The study

guide for CORE is “Applying Pesticides Correctly: A Guide for

Pesticide Applicators” SM-1 or the DVD version which is labeled

as an “Interactive Training by Chapter” and is SM69. The private

applicator manual is titled “Private Applicator Agricultural Pest

Control” and is SM 53; the interactive DVD and manual PDF is SM

73. In Hillsborough County the test is given on the third Tuesday

of each month and starts at 9:00 am. You must bring a photo ID

with you to take the test and there is no charge for taking the test.

Each test is 50 questions. A passing score is 70% and higher so you

must get at least 35 questions correct. Your test will be sent in for

grading and you will receive your results back from the FDACS-

Bureau of Compliance Monitoring in several weeks. If you have

passed both tests you will be sent paperwork to fill out and send in

along with your license fee and then your new pesticide license

will be sent to you.

Licenses are renewed every 4 years. About 6-8 weeks

before your license expires you will mailed paperwork for

renewing. You will need to fill out the forms and send in with your

Continuing Education Unit (CEU) paperwork and your renewal fee.

To renew a private applicator license you will need a minimum of 8

CEUs. You must have 4 CORE CEUs and 4 Private Applicator

CEUs for renewal. If you do not have enough there are 2 things

you can do. The first option is to take both tests over again and get

a new license. The second is that there is a grace period of time to

renew with a financial penalty and you can try to get the CEUs you

need in that grace period. Of course the easiest way is to regularly

attend meetings so that you are getting your CEU points all through

the 4 year renewal period as well as keeping current on pest and

pesticide issues with your crops. If you have any questions get in touch with me at

awhidden@ufl.edu or at 813-744-519 ext. 54134.

Hoping for a great season... Alicia Whidden

2

Thrips management in strawberries Hugh Smith, GCREC Entomologist and Alicia Whidden,

Hills. Co. Extension Agent

Thrips were difficult to manage for many

strawberry growers in Hillsborough County in the

2012-13 season. There were reports that products

such as Radiant were not working as well as

previously. Tests of a few thrips populations

collected from strawberry and vegetables in the

area have indicated that some populations of thrips

have developed tolerance to the spinosyn group of

insecticides. Spinosyns include spinetoram and

spinosad, and are the active ingredients in Radiant

and Entrust. Delegate is the name of the spinosyn-

based insecticide labeled for citrus and blueberries,

and Conserve is the spinosyn product labeled for

ornamentals. Dow Agrosciences, which produces

Radiant and Entrust, has requested that strawberry

growers in Hillsborough County not use Radiant or

Entrust during the 2013-14 season out of concern

that thrips populations resistant to the spinosyns

have developed.

A list of active ingredients available to

manage thrips on strawberry in Florida is presented

in Table 1. In addition to spinosad and spinetoram,

acetamiprid (Assail), naled (Dibrom) and

novaluron (Rimon) are among the active

ingredients that have contributed to suppression of

thrips in strawberry. The active ingredient is the

component in the insecticide that actually kills the

target pest. Active ingredients are assigned a mode

of action number by the Insecticide Resistance

Action Committee (www.irac-online.org). The

number corresponds to the specific target site or

pathway that the active ingredient effects. For

example, the insecticides Malathion and Dibrom

have different active ingredients, but they are both

organosphosphates and so have been assigned the

mode of action number 1B (Table 1). They kill

insects by disrupting the same nervous system

functions. Botanical insecticides such as

azadirachtin products (neem) and microbial

products such as Mycotrol and Grandevo are often

not assigned a MOA number. Similarly, products

that interfere mechanically with pest movement

and feeding such as stylet oils or Surround are not

assigned a MOA number.

Resistance to insecticides develops

when the same mode of action is applied to

successive generations of the same pest. We

can assume that a thrips generation in

strawberry will span 3-4 weeks. Within a four

week interval, the same mode of action can be

applied more than once to suppress thrips, if the

label allows. However after using a certain

mode of action, the grower should switch to

alternative modes of action for a four week

period or longer. The most common thrips

species in strawberry in Hillsborough County is

Florida flower thrips (Figure. 1), which is

thought to be less damaging than western

flower thrips (Figure. 2). It is not possible to

distinguish between the two species without a

microscope and training. Both species of thrips

are fed upon by predatory minute pirate bugs

(Figure. 3), which are found in strawberry and

other crops if broad spectrum insecticides are

not used.

(Continued on page 3)

Figure 1. Florida flower thrips adult. Photo: Lyle Buss.

Figure 2. Western flower thrips adult. Photo: Lyle Buss.

3

Flower thrips become abundant in the flowers of weeds and

trees, including citrus, and can migrate in large numbers

during certain times of the season into horticultural crops such

as strawberry. Sometimes it is unclear if the failure of

insecticides to suppress thrips is due to insecticide resistance,

high levels of migration from outside the field, or a

combination of these and other factors. Because of the mild

winter, some growers began spraying for thrips in January of

this year, while colder winters normally delay the onset of

thrips problems till February. If we experience another mild

winter, we can assume that difficulties will be encountered

in 2014 managing thrips and other pests in strawberries.

Hugh Smith and Alicia Whidden will be working with

strawberry growers this coming season to get a better understanding of why thrips have become more

difficult to manage.

Please contact us if you have any questions.

Hugh Smith – tel: 813-633-4124; email: hughasmith@ufl.edu.

Alicia Whidden – tel: 813-744-5519 ext. 54134; email: awhidden@ufl.edu.

Table 1. Some insecticides labeled for thr ips management on strawber ry.

Active Ingredient Examples MOA #**

Abamectin Agri-Mek 0.15 EC; Temprano; Zoro 6

Acetamiprid Assail 30 SG; Assail 70 WP 4A

Azadirachtin Aza-Direct*; Azatin XL; Ecozin Plus 1.2% ME* UN-botanical

Azadirachtin; Pyrethrins Azera* UN + 3A

Beauvaria bassiana strain GHA Mycotrol O* UN - microbial

Chromobacterium subtsugae Grandevo* UN - microbial

Kaolin Surround WP* UN

Malathion various 1B

Naled Dibrom 8 (restricted) 1B

Novaluron Rimon 0.83 EC 15

Paecilomyces fumosoroseus PFR-97 20% WDG* UN - microbial

Peppermint oil; Rosemary oil Ecotec* UN - botanical

Piperonyl butoxide; Pyrethrins Evergreen EC 60-6 UN + 3A

Pyrethrins Pyganic EC 1.4 II* 3A

Spinetoram Radiant SC 5

Spinosad SpinTor 2 SC; Entrust SC* 5

Sulfoxaflor Closer 4C

*OMRI listed; ** Insecticide Resistance Action Committee Mode of Action number

Figure 3. Minute pirate bug, a thrips predator.

Photo: Hugh Smith.

4

‘Florida Sensation’ Strawberry Vance Whitaker, GCREC Strawberry Breeder

The University of Florida strawberry breeding

program has released ‘Florida Sensation’ (U.S.

PPAF), a new cultivar which was previously trialed

as FL 09-127. As the trial number suggests, this

cultivar was selected as a seedling during the 2009-

10 season, and after additional years of scrutiny

was tested by grower cooperators in west-central

Florida during the 2012-13 season. Plants will be

commercially available to Florida growers

beginning in fall, 2014.

Figure 1. ‘Flor ida Sensation’ grown in Dover , FL

during the 2012-13 season.

Notable characteristics of ‘Florida

Sensation’ based on UF trial data include:

High early and total yield similar to ‘Florida

Radiance’.

Fruit size equal to or greater than ‘Florida

Radiance’ throughout the season.

Good firmness, intermediate between

‘Florida Radiance’ (medium firmness) and

Winterstar™ (high firmness).

Bright red color that maintains fresh

appearance postharvest.

Sweet flavor The flavor of this cultivar has been examined

in multiple sensory panels, in which “sweetness” was

rated higher than ‘Florida Radiance’ on 6 of 7 dates

tested and “flavor” was also rated higher on 5 of 7

dates tested. This is consistent with soluble solids

content data, which showed higher soluble solids for

‘Florida Sensation’ than for ‘Florida Radiance’ on all

5 dates tested.

I nitial disease resistance trials in collaboration

with Dr. Natalia Peres indicate that ‘Florida

Sensation’ has a very similar disease resistance profile

compared with ‘Florida Radiance’, except that the

new cultivar appears to have greater resistance to

Colletotrichum crown rot. While this new cultivar

has greater plant vigor than ‘Florida Radiance’, the

genetic susceptibility of ‘Florida Sensation’ to

Phytophthora root and crown rots is of concern, and

both nurserymen and growers are urged to take

preventative action against this disease.

A limited number of trial plants of ‘Florida

Sensation’ will be available on or around October 1st

for trial this season. The Florida Strawberry Growers

Association will be managing the distribution of these

plants in collaboration with Florida Foundation Seed

Producers, and all inquiries should be directed to the

FSGA.

Figure 2. Disease resistance/

susceptibility of ‘Florida Sensation’ in

comparison with industry standards

based on initial trial data. R= Resistant;

MR=Moderately Resistant;

MS=Moderately Susceptible;

S=Susceptible; HS=Highly Susceptible.

5

Economic Survey Results and Follow-up Research Projects Zhengfei Guan, GCREC Ag Economist and Alicia Whidden,

Hills. Co. Extension Agent

The Florida strawberry industry is facing

various challenges, and the top three on the

growers’ list are Mexican competition, government

regulation, and labor shortages, according to a

comprehensive industry survey we conducted early

this year.

In 2012, Florida strawberry acreage was at

10,100 acres, up from 9,900 in the previous year.

However, the total production was down by 20%

compared to that of the previous year. Our survey

shows that 600-700 flats were left in the field,

while imports of Mexican strawberries were

flooding the market.

Mexican strawberry acreage jumped

dramatically from 17,000 acres in 2011, to 20,800

in 2012, and 25,100 in 2013. The Mexican

Department of Agriculture, Livestock, Rural

Development, Fishing and Food (SAGARPA) is

now pushing to double the acreage in 5 years.

Mexico has the same production window as

Florida. Its total production is estimated at over

600 million pounds in 2012, roughly 3 times

higher than Florida production.

U.S. imports of strawberries increased by

44% in 2012, and the same year the U.S. became a

net importer of strawberries for the first time. Total

imports reached a record 351 million pounds,

almost exclusively from Mexico (99.7%). The

volume imported was almost twice total Florida

production. The imports from Mexico may

continue to increase because of lower costs and

increasing Mexican production capacity.

This situation has been seen before in the

tomato industry, which just managed to increase

the floor price for Mexican tomatoes after a painful

battle. Could this be done for strawberry growers?

Approximately 80% of survey respondents think

Mexico is dumping its strawberries and that the

U.S. government should take action and launch an

anti-dumping investigation.

This information has been shared with

Secretary of Agriculture Tom Vilsack and the

State legislature to communicate various threats

and challenges facing the industry. Besides

Mexican competition, growers rank government

regulation and labor shortages as major threats.

Growers are very concerned about

increasing government regulation. The ban of

methyl bromide created a technological shock for

the industry in the last few years. The latest

example of regulation is the Federal Food Safety

Modernization Act. Food safety measures were

once optional but will soon become mandatory

for the industry, and will incur additional costs to

production.

Growers in Florida are worried about

labor shortages, which partly contributed to

strawberries being abandoned in the field. The

survey suggests that very few growers used the

Guest Worker Program that was set up to bring

in foreign workers. Growers think the current

Guest Worker Program is “expensive and

cumbersome” and needs to be overhauled.

However, many growers indicated they will have

to hire Guest Workers in the next two years

because of labor shortages.

Roughly 30 percent of respondents

indicated they would downsize their operation

when asked early last season. Mexican

competition, government regulation, and labor

shortage were the main reason.

While the industry is facing serious

challenges, there are a few points that need to be

noted regarding the future of the industry.

Agriculture is a risky business. Mexican

strawberry production is not an exception. It is

also subject to uncertainties such as extreme

weather conditions. The bad weather during the

2012/2013 season in Mexico offered some

respite to Florida growers.

Mexican farm labor costs will increase

over time as labor supply experiences structural

shifts from farm work to non-farm industries.

Mechanical harvesting will likely become a

technically feasible and financially viable option

in the future, which could effectively neutralize

the major competitive advantage (labor) of

Mexican strawberries.

Florida growers will continue to have

access to new cultivars the University of Florida

is developing while Mexican growers’ access

might be limited in the future.

Follow-up Projects

As Mexican competition and increasing

(Continued on page 6)

6

costs of production are posing serious challenges

to the industry, the Florida Strawberry Growers

Association (FSGA) is funding two follow-up

research projects to address growers’ concerns.

One aims to provide “A Comprehensive Study of

the Mexico Strawberry Industry.” We will study

Mexican production costs, technologies,

government support, environmental and food

safety policy, and research and development

(R&D) infrastructure, among other issues. The

results will facilitate a comparative analysis with

Florida strawberry production and will help

growers formulate proper strategies to compete

effectively.

The second project will investigate “Cost

Escalation in Florida Strawberry Production and

the Underlying Factors.” The research results will

be used to inform policy making to reduce growers

cost burden. The information will also help

growers in cost management.

Cutleaf Evening Primrose (Oenothera laciniata Hill) Nathan S. Boyd, GCREC Weed Scientist

Cutleaf evening primrose is a common

winter annual or biennial in central Florida. It

emerges, grows, and flowers throughout the year

and can be problematic in commercial vegetable or

strawberry fields where it emerges in the row

middles or planting holes in the plastic mulch. It

typically grows as a basal rosette that is branched

from the base (Figure 2). The leaves are alternate

with coarsely toothed or lobed margins. The plant

tends to grow along the ground (Figure 3) but can

be more upright. Flowers have 4 to 5 yellow to

reddish petals (Figure 4).

Cutleaf evening primrose can be managed

in the row middles with a variety of products with

soil residual activity such as Chateau. Plants

emerging through planting holes can be controlled

with herbicides such as Goal that are applied under

the plastic. Aim and Gramoxone can be applied in

row middles for cutleaf evening primrose control

and are most effective when the plants are small.

Figure 1. Cutleaf evening pr imrose seedling. Note

the whitish colored veins.

Figure 2. Cutleaf evening pr imrose basal rosette with

branches emerging from base.

(Continued on page 7)

7

Herbicide Options for Strawberry

Nathan S. Boyd, GCREC Weed Scientist

Strawberry production in Florida relies on

fumigation to achieve adequate levels of pest

control. For many years growers relied on methyl

bromide until its use was phased out. In recent

years, extensive research has been conducted to

identify alternative fumigants and has resulted in

the registration of multiple methyl bromide

alternatives. Although pest control achieved with

alternative fumigants has looked promising in some

studies, it is generally acknowledged that the

registered alternatives tend to provide poor or

inconsistent weed control. This is especially true

Figure 3. Mature plant with yellow flowers. Note the

prostrate growth.

Figure 4. Yellow flowers that are open from dusk to ear ly

morning.

for purple and yellow nutsedge (Cyperus rotundus

and C. esculentus) which are two of the most

invasive weed species in Florida. They are

especially problematic due to their ability to

penetrate polyethylene mulches and successfully

compete with strawberry. It is likely that effective

weed management post methyl bromide will

require the adoption of more integrated pest

management approaches than were used in the

past that include effective fallow programs, cover

crops, pre- and post emergence herbicides,

fumigation, plastic mulches, and tillage.

There are several herbicides registered for use in

strawberry that can be broadcast applied prior to

transplant, applied under the plastic, applied to

the row middles, or broadcast over the top. It is

important to understand how herbicides work to

minimize risk of damage and maximize

effectiveness. Contact herbicides (eg. Aim) tend

not move in the plant whereas systemic herbicides

(eg. glyphosate) readily move in the plant.

Adequate coverage is needed when using contact

herbicides to achieve satisfactory control. Soil

residual herbicides (eg. Devrinol) inhibit

germination or the growth of emerging seedlings

but have no impact on emerged weeds. Other

herbicides (eg. glyphosate) have little to no

activity in the soil and must come in contact with

plant material to be effective. Herbicides should

be selected that fit into your current management

plan and are effective on the most problematic

weed species present in your field.

(Continued on page 8)

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Trade Name (active ingredient)

Max. Rate (per acre)

Use

Aim EC (carfentrazone)

2 oz Burn down of emerged broadleaf weeds prior to transplant.

Chateau 51 WDG (flumioxazin)

3 oz Broadleaf weed control in row middles. Apply to weed-free soil before laying plastic mulch at least

30 days before transplant.

Devrinol DF XT (napropamide)

8 lbs Apply to weed-free soil before laying plastic mulch.

Goal 2 XL (oxyfluorfen)

2 pt Apply to weed-free soil before laying plastic mulch at least

30 days before transplant.

Prowl H2O (pendimethalin)

1.5 pt Weed control in row middles with hooded applicator. 35

day PHI.

Scythe (Pelargonic acid)

10% v/v Burn down of emerged grasses and broadleaves.

Sinbar WDG (Terbacil)

4 oz Apply to weed-free soil before laying plastic. 110 day PHI.

Various (glyphosate)

variable Emerged broadleaf and grass control.

Trade Name (active ingredient)

Max. Rate (per acre)

Use

Aim EC (carfentrazone)

2 oz Broadleaf weed control in row middles with hooded

applicator.

Chateau 51 WDG (flumioxazin)

3 oz Broadleaf weed control in row middles with hooded

applicator.

Gramoxone (paraquat)

2 pts Weed control in row middles with hooded applicator. 21

day PHI.

Poast 1.5 EC (sethoxydim)

2.5 pts Emerged grass weeds. 7 day PHI.

Prowl H2O (pendimethalin)

1.5 pts Weed control in row middles with hooded applicator. 35

day PHI.

Scythe 4.2 EC (pelargonic acid)

10% v/v Directed spray to row middles for burn down of emerged

grasses and broadleaves.

SelectMax (clethodim)

16 oz Emerged grass weeds. 4 day PHI with single application

and 14 day PHI with multiple applications.

Stinger (Clopyralid)

2/3 pt Emerged broadleaf weeds. 7 day PHI.

Various (glyphosate)

variable Emerged broadleaf and grass control.

Table 1. Herbicides that can be applied before transplant. This information is intended to be used as a

brief summary of herbicide options. Consult product label before use.

Table 2. Herbicides that can be applied after transplant. This information is intended to be used as a br ief

summary of herbicide options. Consult product label before use.

(Continued on page 9)

9

Weed Species A

i

m

E

C

C

h

a

t

e

a

u

D

e

v

r

i

n

o

l

G

o

a

l

G

r

a

m

o

x

o

n

e

G

l

y

p

h

o

s

a

t

e

P

o

a

s

t

P

r

o

w

l

S

c

y

t

h

e

S

e

l

e

c

t

m

a

x

S

i

n

b

a

r

S

ti

n

g

e

r

Activity R R/

F

R R F F F R F R F

Grass weeds

Crowsfoot grass (Dactyloctenium

aegyptium)

T T U U S S U S SD S S T

Goose grass (Eleusine indica)

T S S S S S S S SD S U T

Large crabgrass (Digitaria sanguinalis)

T S S S S S S SS SD S S T

Broadleaf weeds

Black medic (Medicago lupulina)

U U U U U S T U S T U SD

Carolina geranium (Geranium carolinianum)

U U U S U S T U S T S SD

Common purselane (Portulaca oleracea)

S S S S S S T U S T S U

Cutleaf evening-

primrose (Oenothera laciniata)

SD S U S SD S T U S T U SD

Eclipta (Eclipta prostrata)

S S U U S S T U S T U U

Florida pusley (Richardia brasiliensis)

SD S U S SD S T U S T S U

Nightshade, American (Solanum americanum)

S S U S S S T U S T U S

Nutsedge, yellow (Cyperus esculentus)

T T T T SD S T U SD T SD U

Nutsedge, purple (Cyperus rotundus)

T T T T SD S T U SD T U U

Pigweed, Redroot (Amaranthus retroflexus)

S S S S S S T U S T U U

Pigweed, Smooth (Amaranthus hybridus)

S S U S S S T U S T U U

Pigweed, Spiny (Amaranthus spinosus)

S S U S S S T U S T U U

Table 3. Susceptibility of select weed species to herbicides registered for use in strawber ry. This

information is provided to give a concise overview of expected weed susceptibility to herbicides based on

information contained in the label. Consult product label before use.

10

Fungicide resistance monitoring of Botrytis Achour Amiri, GCREC Post-Doc Researcher and

Natalia A. Peres, GCREC Plant Pathologist

Resistance of Botrytis to many

fungicides has been a serious problem in

strawberry fields in Florida for the last

couple of years. Eighteen strawberry

fields were screened for resistance to

most fungicides used to control Botrytis

fruit rot (BFR) in 2013. As shown in

Figure 1, resistance to Cabrio® and

Topsin-M® is widespread across all

locations. These two fungicides should

no longer be used to control BFR.

Resistance to Pristine® persisted in

locations surveyed previously and

ranged from 40 to 85%. Because of

cross-resistance with boscalid (one

active ingredient of Pristine), resistance

to the newly registered Fontelis® was

detected at frequencies varying between

15 to 50%. However, no resistance was

found to Luna® (from the same

chemical group as boscalid and

Fontelis®), which is expected to be

registered soon. As seen in previous

seasons, resistance to Scala® was found

in all locations at frequencies varying

between 18 and 82%. This level of

resistance was also found to cyprodinil,

one of the active ingredients of

Switch®, which is known to be cross-

resistant to Scala®. Resistance to

Elevate® was also confirmed in all

locations but at lower frequencies

compared to the other fungicides. For

the first time, resistance to Rovral® was

found at low frequencies (8 to 30%) in

seven locations in Florida and a few

isolates with low sensitivity to Switch®

were found in three locations. Although

the risk of developing resistance to these

two last fungicides is low, their

extensive use in the fields may select for

resistant populations slowly.

Our recommendation for the

upcoming season is to use captan or

thiram early in the season, when

conditions are not as favorable for disease, or when there is

not much bloom. When conditions for disease

development are moderate, Elevate®, Fontelis® and

Scala® can be used once or twice at most during the

season. Switch® should be saved for periods when

conditions are highly favorable for disease development.

Growers can find out whether conditions are favorable for

disease at http://agroclimate.org/tools/strawberry and sign

up to receive email and/or text message alerts. The table

below summarizes our findings with the fungicide groups

studied and control recommendations. Please do not

hesitate to contact Natalia (nperes@ufl.edu) or Achour

(aamiri@ufl.edu) for additional information.

(Continued on page 11)

11

Chemical (active ingredient)

Fungicide Group Remarks

Thiram Granuflo (thiram)

M3

Low risk of resistance development. Should be

preferred early in the season when conditions are not as

favorable for BFR, or when there is not much bloom.

Captan, Captec (captan)

M4

Low risk of resistance development. Should be

preferred early in the season when conditions are not as

favorable for BFR, or when there is not much bloom.

Topsin (thiophanate-methyl)

1 Resistance widespread. Not recommended for BFR

control.

Rovral (iprodione)

2 Label does not allow more than 1 application per season

and no application “after first fruiting flower”.

Fontelis (penthiopyrad)

7

Resistance detected. Do not use more than once or

twice per season. Tank-mixing with captan or thiram

may help delay resistance development.

Luna (fluopyram)

7 Not yet labeled for use on strawberries

Scala (pyrimethanil)

9 Resistance detected. Do not use more once per season.

Tank-mix with captan or thiram is recommended.

Switch

(cyprodinil + fludioxonil) 9 + 12

Recommended to use when conditions are highly

favorable for BFR.

Cabrio (pyraclostrobin)

11 Resistance widespread. Not recommended for BFR

control.

Pristine

(pyraclostrobin + boscalid) 11 + 7

Resistance widespread. No longer recommended for

BFR control.

Elevate (fenhexamid)

17

Resistance detected. Do not use more once or twice per

season. Tank-mixing with captan

(Captevate®) or thiram is recommended.

Studies on the survival and control of the charcoal rot fungus Macrophomina phaseolina Natalia A. Peres1, Jim Mertely2, and Joe Noling3, 1,2GCREC

Plant Pathology, 3CREC, Nematology

Macrophomina phaseolina was first observed

causing charcoal rot disease on Florida

strawberries in 2001. Infected plants showed

signs of water stress and subsequently collapsed,

especially early and late in the season when

temperatures are warmer. These symptoms are

similar to Colletotrichum and Phytophthora

crown rots, caused by C. gloeosporioides and P.

cactorum, respectively, so suspected samples

should be submitted to a diagnostic clinic for

correct identification.

During the last season, we conducted

studies evaluating the oversummer survival of

Macrophomina phaseolina on dead strawberry

crowns and the effect of fumigants on the fungus.

Survival of Macrophomina over summer

In August 2012, dead strawberry crowns

were collected from seven fields where plastic

was going to be reused for the following season.

Macrophomina phaseolina was recovered from

the dead crowns from all seven farms indicating

the fungus can survive during the summer on

dead plants. The percentage of infected crowns

and the number of Macrophomina colonies per

gram of crown seems to be higher on farms that

had a previous history of charcoal rot. However,

the pathogen was detected even in farms that did

not have a history of charcoal rot disease. This

indicates the potential for inoculum accumulation

that could lead to disease problems in the future.

The number of colonies per gram of crown was

lower in farms that used soil fumigants such as K-

Pam and Vapam than on two farms that only used

Roundup for crop destruction. During the

upcoming 2013-14 season, more farms will be

sampled to confirm these results.

(Continued on page 12)

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Effect of fumigants on inoculum control

Methyl bromide and some alternative

fumigants were evaluated for the control of M.

phaseolina inoculum on infected strawberry

crowns buried in the soil prior to drip

applications (K-pam, Vapam or

DMDS+Chloropicrin+Telone) or immediately

following shank application (methyl bromide,

Telone, DMDS+Chloropicrin,

DMDS+Chloropicrin+Telone, TeloneC35, or

Chloropicrin). The number of surviving spores

(microsclerotia) of M. phaseolina was quantified

by counting the fungi colonies, and comparing to

controls buried in untreated beds.

Preliminary results show that K-Pam, Vapam,

DMDS, and Telone C35 used in conjunction with

VIF (virtually impermeable film) were as

effective as methyl bromide in reducing

Macrophomina inoculum. Telone C-35 applied

under LDPE (low density polyethylene) was less

effective than application under VIF.

Surprisingly, chloropicrin applied alone was not

effective against M. phaseolina. These results

demonstrate the potential for different fumigants

to control Macrophomina inoculum. This trial

will be repeated during the 2013-14 season to

confirm the efficacy of these materials and the

application method.

Strawberry Producer Survey Dr. Emily Hoover's

National Strawberry

Sustainability Initiative

project team from the

University of Minnesota is

looking for current and potential growers to

participate in an online survey. Their project is

funded in part by a grant from the Walmart

Foundation and administered by the University of

Arkansas System Division of Agriculture Center

for Agricultural and Rural Sustainability. They

believe that the feedback from current and

potential strawberry growers will help to develop

a comprehensive e-learning tool that will teach

sustainable methods and marketing and growing

technologies for new strawberry growers. If you are currently a farmer growing

strawberries or you are considering becoming a

strawberry grower, please take 5 minutes to

complete this survey at http://z.umn.edu/

strawberryetool. If you have questions regarding

the survey, please contact Echo Martin, the

project coordinator. His email address is

mart1794@umn.edu.

Wednesday, November 6 Register today at www.floridaagexpo.com

Ag Expo Scheduled Field Tours at 10:30 a.m. and 1:00 p.m. Using Copper and Copper Alternatives for Bacterial Leaf Spot Management on Tomatoes

Evaluating the Efficacy of Methyl Bromide and Alternative Fumigants Against Weeds, Nematodes and Soilborne Diseases for Tomato Production

Integrating Resistant Tomato Varieties, Mulch and Insecticidal Programs to Minimize Losses to Tomato Yellow Leaf Curl

Integrated Management of Arthropod Pests in Protected Agriculture

Post Emergence Herbicides for Nutsedge Control in Peppers, Tomatoes and Cantaloupes

Impact of Moisture Level Within the Bed on Herbicide

Effectiveness Integrated Weed Management Plans for Tomatoes

Improvement of Tomato Cultivars Through Breeding and Genetics

Tomato Variety Trials

Strawberry Varieties for Early Planting

Improvement and Evaluation of New Ornamental Crops

Avoiding Soil Fumigation with Soilless Culture of Vegetable and Fruit Crops

Using Soil Surfactants and Herbicides to Improve Metam Potassium Efficacy Against Nutsedge

Passive Removal of Nitrogen for On-site Wastewater (Septic) Systems

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