Document ID: EPA-HQ-OPP-2005-0123-0338
Agency: epa
Document Type: Supporting & Related Material
Title: 
Posted Date: 2007-05-02T04:00Z

ro

  SEQ CHAPTER \h \r 1 UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

WASHINGTON D.C., 20460

OFFICE OF

PREVENTION, PESTICIDES AND TOXIC SUBSTANCES

MEMORANDUM

SUBJECT:	Assessment of the Benefits of Soil Fumigation with
Chloropicrin, Methyl Bromide, Metam Sodium and Dazomet in Ornamental
Production

FROM:	Nicole Zinn, Biologist

Biological Analysis Branch

		Stephen Smearman, Economist	

Economic Analysis Branch

Biological and Economic Analysis Division (7503P)

THRU:	Arnet Jones, Chief 	

Biological Analysis Branch

Timothy Kiely, Chief 

Economic Analysis Branch

Biological and Economic Analysis Division (7503P)

TO:		John Leahy 

Special Review and Reregistration Division (7508P)

PRODUCT REVIEW PANEL DATE:  April 11, 2007

SUMMARY

This assessment attempts to measure the benefits of soil fumigation
through the characterization of the industry in terms of total value,
area and type of production and the various types of pest control
alternatives available to growers.  There is very little data available
to conduct a thorough analysis of the benefits of fumigation to
producers of ornamentals, and the Agency is requesting information that
will assist with the determination of the benefits of fumigant use. 

The ornamentals industry is extremely diverse and is characterized by
numerous crop species and varieties, with multiple cropping systems in
different environments.  According to USDA NASS, in 2005, the
floriculture industry was valued at $5.36 billion, with bedding and
garden plants accounting for more than 50 percent of the total value of
production, or $2.68 billion.

Methyl bromide and chloropicrin are the dominant fumigants used in the
production of ornamentals, but 1,3-dichloropropene, metam sodium and
dazomet are also used.  Fumigants are used in ornamental production to
control diseases, nematodes and weeds.  Based on the available data, an
estimated 1 to 4 percent of ornamental production operations use
fumigants, however the benefits derived from fumigation can be quite
substantial in terms of higher yields, higher quality plant production,
and lower costs of production.  In addition, the benefit to the
propagative sector of the industry assures the availability of viable
stock that is not contaminated with disease or nematode pests, which
affects the future revenues of other sectors in the industry.  

Background

As part of the Reregistration Eligibility Decision (RED) process, EPA is
assessing the risks and benefits of the use of several soil fumigants:
dazomet, chloropicrin, metam potassium, metam sodium, and methyl
bromide.  This document presents the assessment of the benefits provided
by the soil fumigants in the production of ornamentals.  As such, for
the sectors of the floriculture industry where information is available,
it compares the current situation in which fumigants are available for
use, subject to existing label restrictions, to the situation that is
estimated to occur where the fumigants are not available.  This is
somewhat different from an assessment of the impacts of regulation, as
no specific regulatory scheme is considered and a partial budget
analysis is not utilized.  

BEAD has limited information for ornamental crops but has attempted to
characterize the industry and the benefits of fumigation with the
information available.  Most of the information available is for
California and Florida, with some additional information for Michigan,
Hawaii and the Pacific Northwest.  The Agency is requesting information
that will assist with the determination of the benefits of fumigant use.

U.S. FLORICULTURE INDUSTRY

The United States ornamentals industry is extremely diverse and is
characterized by numerous crop species and varieties, with multiple
cropping systems in different environments.  This assessment will focus
on cut flowers, cut foliage, herbaceous perennials, bulbs and plant
propagative material, in both open fields and protected environments
(tunnels, open-ended and closed hoop-houses, shade houses, and permanent
greenhouses). 

The floriculture industry was valued at $5.36 billion according to the
USDA NASS Floriculture Crops 2005 Summary.  The floriculture industry
includes bedding and garden plants, herbaceous perennials, flowering
hanging baskets, potted flowering plants, foliage plants, cut flowers,
cut cultivated greens, and propagative material.   The sectors of the
ornamental industry for which data and information were available and
that are presented in this document include foliage plants, cuts
flowers, cut cultivated greens, and propagative material.  These crops
account for approximately 31 percent of that value or $1.66 billion.  As
stated earlier, bedding and garden plants account for $2.68 billion or
approximately 51 percent of the industry value. 

Nationally, the five leading states in terms of production are
California, Florida, Michigan, Texas and New York out of 36 program
States surveyed.  There were approximately 62,378 total acres in
floriculture production in 2005 with about one-third under protective
cover.  Of this proportion, about 60 percent is under green house cover
and about 40 percent in shade and temporary cover.  In 2005, the USDA
NASS Floriculture Summary estimates that open ground usage totalled
41,350 acres.

.  

USDA NASS estimates that the number of growers in 2005 was approximately
10,563 which is down from 11,385 growers in 2004, a 7 percent decline. 
The industry appears to be consolidating as the number of growers and
the total area in terms of the number of square feet in production have
been declining in all size categories when comparing data from the 2002
Census and the NASS 2005 Floriculture Crops Summary estimates (See Table
1).

Florida is the leading producer of foliage plants with approximately 69
percent of the value. California is the leading producer of cut flowers
with 73 percent.  For cut cultivated greens, Florida is the leading
producer with 75 percent of the total value of program States surveyed
and for propagative material Florida, Michigan, and California account
for 56 percent of the program states surveyed.  Propagative material had
a value of $439 million in 2005 with approximately 49 percent of the
total value or $215 million accounted for by annual bedding and garden
plants according to NASS. (USDA NASS, 2006)

This document does not include other aspects of the ornamental industry,
such as Christmas tree nurseries or nursery stock.  It is not within the
scope of this document to explain every cropping system in the industry.
 The objective is to provide a basic understanding of the industry and
its complexities, and to describe the major issues that growers in this
industry face.  In addition, this industry changes rapidly and
therefore, the species and varieties grown also changes.  For example,
several years ago sunflowers were not a major ornamental crop in Florida
but now they are.  See Appendix A for a list of some of the crop species
grown.

Crop Characteristics:  Plant Varieties, Crop Systems and Crop Rotations

California

There are three basic systems in place for cut flower and bulb crops in
California.  Annuals are shallow rooted crops that represent 50 to 60
percent of the industry.  They are often planted to a depth of 6 to 8
inches.  Fumigants can be shanked into the preformed beds or
drip-applied from drip tapes placed on top of beds under plastic mulch. 
Bulb crops represent about 30 percent of the industry.  Fumigants are
applied by deep shanking.  Bedding up generally occurs after planting
the bulbs.  Perennials are deep-rooted multi-year crops and represent 10
to 20 percent of the industry in California.  Fumigation needs to
penetrate to a depth of 2 to 3 feet and may require multi-level
shanking. 

Species grown in California include ranunculus and calla lilies (see
Appendix A for additional species grown). Many crops, such as
ranunculus, are grown outdoors in open fields.  Ranunculus is grown as
an annual in the field.  In fall, seeds are planted on beds.  Flowers
are harvested in the spring and the tubers are harvested in July and
August.  These tubers are used in landscaping and are planted in the
fall (Elmore et al, 2003).  The tubers, which are distributed worldwide,
are also used in commercial production.  However, fumigants are also
used when cut flowers are produced in greenhouses.

A California cut flower producer may grow many ornamental species and
hundreds of individual varieties.  Crops are grown in rotation on an 8
to 16 week interval per year on the same parcel of land.  Although
species are rotated, the complex nature of this crop makes a typical
crop rotation impossible to identify.  Instead, an example of how a
rotation is outlined is described here. A crop rotation system for a
grower may involve several annuals.  The first annual crop is planted
and then harvested 90 to 180 days later.  A different species is planted
immediately after the first harvest.  The second harvest follows
approximately 90 to 180 days later.  A third crop is then planted. 
Fumigation would occur when the production starts to decline, which may
be an interval of one to two years.  On the same farm, most growers
produce numerous species, including annuals, perennials, and bulbs.  The
rotation involving various species would be more complex than this
example.  

In California, where an ideal climate for ornamental crop production is
often desirable coastal areas, the field grown ornamental industry
produces many crops.  However, this climate also makes it highly
desirable for residential development, resulting in high land prices and
proximity of fields to residential areas. As mentioned above, the
industry is characterized by numerous crop species and varieties, with
variation in pest and chemical susceptibility.  To stay competitive,
growers often introduce new varieties.  When new varieties are
introduced, the susceptibility of the plant to pests or to residual
pesticide applications is often unknown. (SAF, 2005)

Florida

In Florida, some of the typical cut flowers grown are snapdragons,
lilies, gladiolus, lisianthus, delphinium, and sunflowers.  A production
system for a grower may involve several species.  Growers rotate to
other cut flower species, but not to other crops.  Planting occurs
between August and March, with harvesting occurring October through May.
 Two to three plantings occur each year, with only a single annual
application of fumigants, such as methyl bromide + chloropicrin.  As
with California, most growers produce numerous species, including
annuals, perennials, and bulbs, throughout the farm.  The rotation
involving all of these species would be more complex than described
above.  

As in California, in Florida, where an ideal climate for ornamental crop
production is often desirable coastal areas, the field grown ornamental
industry produces many crops.  However, this climate also makes it
highly desirable for residential development, resulting in high land
prices and proximity of fields to residential areas. As mentioned above,
the industry is characterized by numerous crop species and varieties,
with variation in pest and chemical susceptibility.  To stay
competitive, growers often introduce new varieties.  When new varieties
are introduced, the susceptibility of the plant to pests or to residual
pesticide applications is often unknown. (SAF, 2005)

Caladiums are also grown in Florida on either sandy or muck soils.  They
are planted from the middle of March until mid April.  Caladiums are dug
annually from November until the middle of March.  The tubers are
cleaned, graded, repacked, and stored until shipment to customers
throughout the world.  Methyl bromide is applied in the short time
period between the end of harvest of one crop and the planting of the
next.  

Chrysanthemum propagative material is also produced in Florida. 
Chrysanthemum propagative material is shipped to other nurseries to
raise and sell commercially.  Chrysanthemums are planted about 2 to 3
weeks after methyl bromide fumigation.  The plants are grown for 20 to
25 weeks, with cuttings taken weekly for this time period.  These
cuttings are shipped to nurseries to produce finished chrysanthemums. 
The planting beds are then fumigated with methyl bromide again for
replanting in 2 to 3 weeks.  This cycle continues throughout the year,
with about two crop cycles completed per year.  

Michigan

In Michigan, perennial herbaceous nurseries use fumigants, such as
methyl bromide, to control nematodes and weeds.  Some of the species
grown are delphinium, hosta, and phlox.  Herbaceous perennials are grown
in open fields.

Pacific Northwest

The production of ornamental bulbs, including iris, daffodils, and
tulips, are among the species grown in Washington (Roozen, no date).  In
Northern California and Southern Oregon, Easter lilies are produced on
500 to 700 acres (Schmale, 2005).

Hawaii

Major ornamental crops in Hawaii include cut flowers (Anthurium,
tropicals, Protea), orchids, lei products, potted plants and other
nursery products (Tanouye, 2005).

Ornamental crops are grown in other states but BEAD did not have
information on these cropping systems.  The Agency is requesting
information that will assist with the determination of the benefits of
fumigant use.

ACREAGE GROWN 

Floriculture crops (bedding/garden plants, cut flowers and cut florist
greens, foliage plants, and potted flowering plants) are grown in all 50
states (USDA Ag Census, 2002).   The major floriculture production areas
as listed in the USDA Census of Agriculture are described in Table 1. 
In 2002, there were approximately 90,566 acres of floriculture crops
grown in the U.S.  The total combined estimated acreage in 2005
according to the USDA NASS Floriculture Crops 2005 Summary is 62,378
acres, a 31 percent reduction in area in 3 years.  Part of this may be
due to the limitations of the Summary to only include data from
operations with over $10,000 in sales which excludes an untold number of
smaller operations. 

Table 1.  Floriculture1, Acres Grown in the Open and Square Feet Grown
under Glass or Other Protection, by Selected State and U.S. Total ,
2002.

State	Area Under Glass (Sq Feet)	Area in Open Fields (acres)	Total
Acreage

California	146,729,367

(3,368 acres)	18,608	21,976

Florida	320,884,771

(7,367 acres)	12,771	20,138

Michigan	48,186,105

(1,106 acres)	3,880	4,986

New Jersey	17,280,688

(397 acres)	3,441	3,838

Hawaii	28,837,733

(662 acres)	2,913	3,575

Washington	17,831,790

(409 acres)	2,929	3,338

United States	973,658,415 

(22,352 acres)	68,214	90,566

Source:  USDA Census of Agriculture, 2002

1. Floriculture crops include bedding/garden plants, cut flowers and
florist greens, foliage plants, and potted flowering plants, not all of
which will be discussed in this document.

Use of Fumigants 

Use and Usage of Soil Fumigants

Use and usage estimates of soil fumigants are provided by USDA NASS and
can be found in the Agricultural Chemical Usage 2003 Nursery and
Floriculture Summary (USDA, 2004).  The states that are surveyed in this
report include most of the states in the Floriculture Crops 2005 Summary
(except New York) and includes two states not included in the Nursery
and Floriculture Summary (Oregon and Pennsylvania).  In 2003, a combined
total of 771,500 pounds of the following five fumigants (chloropicrin,
1,3-D, dazomet, metam sodium, and methyl bromide) were applied in 6
states (California, Florida, Michigan, Oregon, Pennsylvania, and Texas).
 Table 2 provides the average rates and total amount applied for the
five fumigants.

Table 2.  Fumigant Usage for Program States1 in All Nursery and
Floriculture, 2003

	Chloropicrin	1,3-D	Dazomet	Metam Sodium	Metam Potassium	Methyl Bromide

Rate (lb/acre)	120.59	Not published2	411.79	130.39	Not incl3	195.42

Total applied (1,000 lbs)	255.0	31.5	12.5	22.9	Not incl3	449.6

Source:  USDA NASS Agricultural Chemical Usage 2003 Nursery and
Floriculture Summary, 2004

1 Program states include California, Florida, Michigan, Oregon,
Pennsylvania, and Texas.

2 Not published – Some information was collected during the survey but
was not published.

3 Not incl – metam potassium was not included in the survey

Tables 3 through 7 show the percent of operations using the five
fumigants (chloropicrin, 1-3-D, dazoment, metam sodium, and methyl
bromide) for all nursery and floriculture, all nursery, all
floriculture, and various subsets of the floriculture industry for the
six program states (California, Florida, Michigan, Oregon, Pennsylvania,
and Texas).  

	Table 3.  Percent of Operations Using Chloropicrin, by State, 2003*

Site	CA	FL	MI	OR	PA	TX	Total

	%	%	%	%	%	%	%

All Floriculture	2	<1	<1

<1

Cut Flowers	2	19

	2

Flowering Plants	4

1

Bedding Plants	1

<1

Foliage Plants

	Floriculture Propagation Material

	Cut Cultivated Greens

	Herbaceous Perennials

	1

<1

All Nursery	4	<1	1	1

2	1

All Nursery and Floriculture	3	<1	<1	1

1	1

Source: USDA NASS Agricultural Chemical Usage 2003 Nursery and
Floriculture Summary, 2004

Program states include California, Florida, Michigan, Oregon,
Pennsylvania, and Texas

* Blank spaces indicate no data available.

	Table 4.  Percent of Operations Using 1,3-D, by State, 2003*

Site	CA	FL	MI	OR	PA	TX	Total

	%	%	%	%	%	%	%

All Floriculture	<1

<1

Cut Flowers

	Flowering Plants

	Bedding Plants	1

<1

Foliage Plants

	Floriculture Propagation Material

	Cut Cultivated Greens

	Herbaceous Perennials

	All Nursery	2

	<1	<1

All Nursery and Floriculture	1

	<1	<1

Source: USDA NASS Agricultural Chemical Usage 2003 Nursery and
Floriculture Summary, 2004

Program states include California, Florida, Michigan, Oregon,
Pennsylvania, and Texas

* Blank spaces indicate no data available.

	Table 5.  Percent of Operations Using Dazomet, by State, 2003*

Site	CA	FL	MI	OR	PA	TX	Total

	%	%	%	%	%	%	%

All Floriculture	2

	1

	<1

Cut Flowers	3

2

Flowering Plants

	Bedding Plants

	Foliage Plants

	Floriculture Propagation Material

7

	1

Cut Cultivated Greens

	Herbaceous Perennials

	All Nursery

<1	<1

<1

All Nursery and Floriculture	1

	<1	<1

<1

Source: USDA NASS Agricultural Chemical Usage 2003 Nursery and
Floriculture Summary, 2004

Program states include California, Florida, Michigan, Oregon,
Pennsylvania, and Texas

* Blank spaces indicate no data available.

	Table 6.  Percent of Operations Using Metam Sodium, by State, 2003*

Site	CA	FL	MI	OR	PA	TX	Total

	%	%	%	%	%	%	%

All Floriculture	<1	<1

	<1

Cut Flowers	<1

<1

Flowering Plants

1

	<1

Bedding Plants

	Foliage Plants

	Floriculture Propagation Material

	Cut Cultivated Greens

	Herbaceous Perennials

	All Nursery	2

	<1

	<1

All Nursery and Floriculture	1	<1

<1

	<1

Source: USDA NASS Agricultural Chemical Usage 2003 Nursery and
Floriculture Summary, 2004

Program states include California, Florida, Michigan, Oregon,
Pennsylvania, and Texas

* Blank spaces indicate no data available.

	Table 7.  Percent of Operations Using Methyl Bromide, by State, 2003*

Site	CA	FL	MI	OR	PA	TX	Total

	%	%	%	%	%	%	%

All Floriculture	3	<1	<1	1

<1	1

Cut Flowers	3	19

	2

Flowering Plants	5

1

Bedding Plants	3

	1	<1

Foliage Plants

	Floriculture Propagation Material

	Cut Cultivated Greens

	Herbaceous Perennials

	1	4

	1

All Nursery	4	<1	1	1

2	1

All Nursery and Floriculture	3	<1	1	1

1	1

Source: USDA NASS Agricultural Chemical Usage 2003 Nursery and
Floriculture Summary, 2004

Program states include California, Florida, Michigan, Oregon,
Pennsylvania, and Texas

* Blank spaces indicate no data available.

FUMIGATION CHARACTERISTICS

Target Pests

Fumigants are used to control a variety of nematodes, weeds, and
diseases in ornamental production (Table 8).  BEAD has pest information
for California, Florida, Michigan, and Hawaii.  See Appendix A for key
pests in select ornamental species.  

Table 8. Key diseases, Pests, and weeds

Region 	Key diseases, Pests and weeds 

California	Diseases - Verticillium spp., Fusarium spp., Pythium spp.

Nematodes - Meloidogyne spp.

Weeds - Nutsedge (Cyperus spp.), Malva spp., Poa spp., and previous crop
propagules  

Specific pest problems vary by individual crop and variety.  

Florida	All soil borne diseases, weeds, and nematodes, including  

Diseases - Fusarium spp., Rhizoctonia spp., Phytoplithora, Stromatinia,
Pythium spp., Erwinia

Nematodes - Meliodogyne spp. 

Weeds - previous crop propagules

Specific pest problems vary by individual crop and variety.  

Michigan	Nematodes - Meloidogyne hapla, Pratylenchus spp., Ditylenchus
spp.;

Fungi - Pythium (damping-off, root rot), Fusarium (damping-off, root
rot), Phytophthora, Rhizoctonia; 

Weeds - Cyperus esculentus (yellow nutsedge), Inula brittanica, Oxalis
stricta, Cirsium arvense, Rorippa sylvestri

Hawaii	For the crop Anthurium:

Nematodes - root knot nematodes, burrowing nematodes

Other - soil-borne insects, fungi, weeds 

(Kawate and Tarutani, 2005; Tanouye, 2005)

Use Characteristics

A survey conducted by the Society of American Florists in 2005 (Schmale,
2005) provided some information on the use and usage of fumigants in
different crops in several states.  The results are summarized in Table
9.  Application rates were given in the survey but due to multiple
active ingredients and multiple products, it was difficult to determine
the rate of active ingredient being used.   Table 2 provides average
rate information for several fumigants used in the floriculture
industry.  For individual species or cropping situations, the rates used
can vary considerably.

Table 9.  Fumigant Use and Usage as Reported in a Society of American
Florists Survey 

State	Crop	Fumigants Used	Row/

Broadcast	App Method 	Application Timing

California	Easter lily	1,3-D, metam sodium or both sequentially
Broadcast	Mechanical soil injection (soil cap)	July and August

	Cut flowers	Methyl bromide/chloropicrin (various formulations:  75/25,
67/33, 57/43); metam sodium 	Row or broadcast	Drip, mechanical soil
injection (water cap, tarps)	Throughout year

	Aster	Methyl bromide	n/a	Mechanical soil injection (tarp)	March, June -
August

	Delphinium	Methyl bromide; Methyl bromide/chloropicrin (80:20)
Broadcast	Mechanical soil injection (tarp)	May, July - October

	Stock	Methyl bromide;  methyl bromide/chloropicrin; 1,3-D	Broadcast
Mechanical soil Injection (tarp)	June, September

	Iris	Methyl bromide/chloropicrin (80:20; 75:25); 1,3-D	Broadcast or row
Mechanical soil injection (tarp)	February, May – August, October

	Calla lily	Methyl bromide; 1,3-D/chloropicin; metam sodium	Row	Drip
(tarps)	April - May

Florida	Chrysanthemum propagative material	Methyl bromide/chloropicrin
(98:2)	Broadcast	Shank/chisel injection (tarp)	Every week

	Cut Flowers (snapdragon, lily, gladiolus)	Methyl bromide/chloropicrin
(98:2)	Broadcast or row	Mechanical soil injection (tarp)	June through
December

Michigan	Herbaceous

Perennials	1,3-D/chloropicrin, methyl bromide/chloropicrin, or 1,3-D and
herbicides	Broadcast or row	Mechanical soil Injection (tarp)	May to June
and in August and September

Oregon	Easter lily	1,3-D, metam sodium or both sequentially	Broadcast
Mechanical soil injection (soil cap)	July and August

	Bulbs	Methyl bromide/chloropicrin	Broadcast	Mechanical soil injection
(soil cap)	September

Washington	Iris, lily	Methyl bromide/chloropicrin	Broadcast	Mechanical
Soil Injection (tarp)	March – May; September

	Daffodil, tulip, iris	Metam sodium	Broadcast	Mechanical Soil Injection
(tarp)	May - October

In Washington bulb production, metam sodium needs to be applied to a
depth of 18 inches, which is accomplished with a fumigator developed
specifically for this purpose (Roozen, no date).  Trials with the
fumigator were successful at metam sodium application rates of 55
gallons product/acre (42% metam) and 66 gallons product/acre (Roozen, no
date).  The product was not identified but assuming it was Sectagon 42
or Vapam HL, the rates used were 232-234 lb ai/acre and 279-281 lb
ai/acre.

In Hawaii, metam sodium is used for anthurium (Anthurium andraeanum)
production on about 10 to 15 percent of the acreage.  Since this crop
has a five year crop cycle, metam sodium is only used once every five
years.  The typical application rate is 213 lb ai/acre.  (Kawate and
Tarutani, 2005).  Table 10 provides information describing typical metam
sodium use in Hawaii. 

Table 10.  Fumigant Application Information For Metam Sodium in Hawaii.

	Hawaii (Anthurium)

Application Rate (lb ai/acre)	213

Acres Treated per Day per tractor	0.5

Time of Fumigation	Throughout year

Application Method	Drench

Strip Application	No data

Tarps or Water Caps	Tarp

Acreage Fumigated

For ornamental production, fumigant treatments are often applied to
small acreages.  To demonstrate the small acreage treated with
fumigants, BEAD reviewed California Department of Pesticide Regulation
data for applications of methyl bromide to outdoor grown cut flowers or
greens and greenhouse grown cut flowers or greens in 2005.  This range
includes both greenhouse and open field production. The area treated
averaged 1 acre.  The smallest acreage treated was 0.05 acres and the
largest acreage treated was approximately 30 acres.  (One report of 85
acres treated had such a low number of pounds applied that BEAD did not
believe this number was valid.  In addition, two reports did not have a
unit treated so BEAD could not determine the acreage).  Approximately 80
percent of the reported acreage treated values were less than 1 acre. 
Methyl bromide fumigations were made during every month of the year.
(CDPR, 2005)

In Hawaii, anthurium is grown on 250 acres on 61 farms.  This averages
to about 4 acres per farm.  Metam sodium fumigation occurs on 0.5
acres/day/farm (Kawate and Tarutani, 2005) 

Chemical Control Alternatives

Chemical Control Practices

For ornamental species, growers often use a combination of fumigants,
such as methyl bromide+chloropicrin, 1,3-D+chloropicin, or 1,3-D
followed by metam sodium.

Methyl bromide

Methyl bromide is scheduled for phase out under the Montreal Protocol. 
However, there is a Methyl Bromide Critical Use Exemption for California
and Florida ornamentals, including cut flowers, cut foliage, bulbs and
plant propagative material, in both open fields and protected
environments (tunnels, open-ended and closed hoop-houses, shade houses,
and permanent greenhouses) and Michigan herbaceous perennials.

1,3-dichloropropene (1,3-D)

1,3-D controls nematodes but will not provide adequate control of
diseases and weeds at label rates.  Current buffer zones make using this
alternative difficult because often flowers are produced on small
parcels of land, often near homes.  (SAF, 2005)

Township caps are in place for 1,3-D that limit its use in California
and use restrictions are in place in some Florida counties (SAF, 2005). 
Many crops are grown in coastal areas, where cut flowers are also grown.
 Affecting some rotations are plant back times, which can be 1 to 2
weeks longer with 1,3-D compared to methyl bromide.  

Some growers have found adequate control when 1,3-D is combined with
other fumigants or herbicides.  

Chloropicrin

Controls diseases but does not provide adequate control of weeds and
nematodes.  Adequate efficacy for the pest complex cannot be achieved
with lower use rates (SAF, 2005).  There are also concerns about
phytotoxicity to nearby plantings if greater than 2 percent chloropicrin
is used in a combination (SAF, 2005).  Chloropicrin phytotoxicity to
adjacent beds is a concern for chrysanthemum propagative material
production.  

Metam sodium

Efficacy of metam sodium can be erratic and inconsistent, depending on
soil type, moisture content, and temperature. Many years of research
have indicated difficulty achieving consistent efficacy with metam
sodium on high value ornamental crops.  Also, pest populations tend to
build up over time with metam sodium.  Problematic for bulb growers is
the fact that it suppresses active nematodes, and not the eggs.  Similar
limitations occur with other methyl isothiocyanate (MITC) generators,
such as metam potassium and dazomet.

Dazomet

Dazomet is effective against Fusarium, Rhizoctonia, Erwinia, and
Pseudomonas in some cut flowers (carnation and chrysanthemum).  Plant
back restrictions may cause some growers to be able to grow fewer crops
in a year.  See metam sodium above for additional information on
limitations with MITC generators.

Furfural

This chemical was registered for greenhouse ornamentals in October 2006
to control nematodes and fungal pathogens.  The label describes a
greenhouse as “any enclosed structure type with a nonporous covering
and is large enough to allow a person to enter.”  Some growers
producing in protected structures may not be able to use this material
if the structure is not completely enclosed or if the protected covering
is made up of a porous material.  This chemical cannot be used on field
grown ornamentals.  According to the label, about 23 species are listed
and described as showing tolerance of post-plant drench applications. 
The label also mentions that furfural may injure celosia, coleus, New
Guinea impatiens, lisianthus, petunia, and leather leaf fern and that
not all species and cultivars have been tested.  

Fenamiphos

For anthurium production in Hawaii, fenamiphos could be used but is
being phased out (Kawate and Tarutani, 2005; Tanouye, 2005).

Other chemicals, such as herbicides, may also be available to control
certain pests in specific crops.  The Agency welcomes additional
information on chemical alternatives, as well as cultural control
practices.

Cultural Control Practices

Solarization

Solarization is used to kill pests by using solar energy to heat the
soil, which is accomplished by placing clear plastic on the soil
(McSorley and Wang, 2004; Strausbaugh, 1996).  Solarization seems
promising in Florida cut flower production but would take a while to
adopt.  It must be adapted to work in a broadcast system. It may also
not control pests to an adequate depth (SAF, 2005).  Pest pressures may
build during the first crop preventing a second crop from being planted
(SAF, 2005).  

Solarization takes several weeks to control many pests to a depth of 30
cm.  This length of time for a treatment may not be feasible for many
growers due to the intensive, year-round production situation of the cut
flower industry (Pizano, 2001). 

Solarization is not feasible under Michigan field conditions. 
Production areas in California are mainly coastal where solarization is
not feasible due to cool temperatures and cloud cover most of the year. 

Steam pasteurization

Steam pasteurization can be an effective alternative but it is very
expensive to heat soil uniformly to an adequate depth (0.3 to 0.9
meters) for the length of time required to be effective.  There are also
costs associated with setting up steam systems, especially in
older/established greenhouses.   

Field steam pasteurization is cost prohibitive, in part because of the
high cost of fuels.  Installation of pipes is labor intensive and in
some cases must be removed after steaming to accommodate cultural
practices.  In Florida, some soils prevent burial of pipes to an
adequate depth. (SAF, 2005)  

Crop rotation 

Rotation with other cut flower species is used extensively in cut flower
production.  However, in annual cropping they are generally too short
for the full effects of rotating schemes to be effective. The previous
crop (bulbs, corms) often contaminate the following crop or may harbor
pathogens.  In addition, crop rotation is not really a solution to pest
problems in floriculture because either the crop cycle is too long
(perennials) or the pests persist in the soil for a long period of time
(Pizano, 2001).  Most cut flower species are sensitive to the same
pathogens.  Flower rotations are generally not a true rotation in the
pest control sense.  

Some growers have had success with crop rotation.  In California, some
gladiolus growers are leasing land to strawberry growers.  The
strawberry growers fumigate the land with methyl bromide, and a crop of
gladiolus can follow without additional methyl bromide fumigation.  This
practice is most feasible for large growers and requires flexibility. 
This arrangement is not feasible for calla lily growers because calla
lilies are very susceptible to the root disease complex supported by
strawberries and raspberries.  This type of arrangement is not
guaranteed to be available to growers in the future and relies on
continued availability of methyl bromide. (SAF, 2005)

Soilless media production 

Some crops have had success with soilless media, or substrates, in
greenhouses.  These crops include roses, gerbera, lilies and tulips. 
For some crops using substrates, lilies and tulips, the soil used in
production needs to be fumigated.  After a year or two the soil in the
greenhouse under the crate becomes contaminated with diseases like
Pythium and Phytophthora.  Growers using this system need to reuse the
soil in order for the system to be cost effective.  Methyl bromide is
used in this system to eliminate diseases, old bulbs and weeds.   

In the case of roses and gerberas, substrate production is more feasible
than for other crops because these crops are perennials.  Production in
substrates for these crops results in increased yield and quality.  In
perennial systems, infrastructure costs can be amortized over several
years.  However, due to the high production costs, cut rose production
is decreasing.  

Lilies and tulips are also often grown in substrates.  These crops are
"forced", which means that that the bulbs are planted in crates and
actually grown in very large cooler/growth chambers.  They are stacked
floor to ceiling in these growing rooms for the first 4 to 8 weeks after
planting and then taken into the greenhouse where they are spread out 2
dimensionally for finishing the last 4 to 6 weeks.  This results in a
lower cost of production and a faster turn on space in the greenhouse,
which is very costly. 

There are challenges associated with substrate production. Generally,
for most crops, there isn't an offsetting yield or quality increase to
defer the costs associated with substrate production.   Costs include a
large increase in inputs, capital expenditures for the systems coupled
with high costs of potting mix or substrates, plus the labor to move
crates or install the system.  In addition, growers must be very careful
in substrate systems when it comes to water quality management,
fertility management and disease containment.  Yield losses can be very
high if mistakes are made.  Soil has a buffering capacity that limits
some of the problems that are associated with substrate production.  In
addition, substrates may cause significant increases in the cost of
production.  Some growers that have tried substrates ended up going back
to ground production for the reasons described above.  For example,
Gerbera flowers are sensitive to fertility and water issues in the
substrate system.  Some growers have even moved back to ground
production due the risks that are involved.  

Planting Clean Stock

In Hawaiian anthurium production, planting clean stock would help but
because cinder (volcanic) media are reused and ground media are used,
losses are still expected with this practice (Kawate and Tarutani, 2005;
Tanouye, 2005).

BENEFITS of FUMIGATION

As described above, fumigant(s) used varies by crop.  Some of the next
best alternatives are described below. Cut flowers are often marketed
for a certain time of year or holiday.  Missing specific dates can be
detrimental to the grower and cause severe economic impacts.  Quality is
also a major concern for the industry.

  

Yield and Quality Benefits

California

For many cut flower species, 1,3-D + chloropicrin is considered one of
the best currently available alternatives to methyl bromide.  However,
as currently registered, this alternative to methyl bromide does not
provide sufficient control of weeds and regulatory restrictions, such as
township caps and label application rates, limit use.  

For California (and Oregon) Easter lily production, growers use 1,3-D,
metam sodium or 1,3-D and metam sodium.  Fumigation is necessary to
produce the crop.  Plants will not survive without fumigation (Schmale,
2005).

Two trials were conducted on calla lily rhizomes.  Fumigants were drip
applied.  Based on these trials, yield losses of 39 to 66 percent of
salable rhizomes harvested would be expected if the fumigants were not
available (Gerik et al, 2006).

One trial with ranunculus compared methyl bromide/chloropicrin (50:50),
the preferred treatment, to an untreated control.  Other treatments
(except iodomethane/chloropicrin) were compared to an untreated control
but not to methyl bromide/chloropicrin.  This study suggests that if
methyl bromide/chloropicrin were not available (and in the absence of
other fumigants), yield losses of 34 percent would occur (Elmore et al.,
2003).

Michigan

For herbaceous perennials, if methyl bromide were no longer available
the next best registered alternative is 1,3-D with or without
chloropicrin plus herbicides.  This combination is expensive due to the
material cost and the need for multiple applications.  Use of the
fumigants without herbicides may not adequately control weeds.  However,
contact herbicides may damage the crop in the field, resulting in yield
or quality losses.  Damage to the following crop planted may occur if
soil residual herbicides are used.  

Florida

In Florida, the best available alternative to methyl bromide is 1,3-D +
chloropicrin if use restrictions were removed and labeled use rates
increased.  It is not clear to what extent this alternative would be
used with the current use restrictions and label rates. 

Solarization also seems promising in Florida production but would take
awhile to adopt.  

Solarization takes several weeks to control many pests to a depth of 30
cm.  This length of time for a treatment is not economically feasible
for many growers due to the intensive, year-round production situation
of the cut flower industry.   

Two snapdragon trials were conducted on sandy soils in Florida. The
first study indicated that in the absence of fumigation yield losses
were 6 to 7 percent (McSorley and Wang, 2003). 

In the second study, solarization was one of the treatments used.  All
treatments were affected by a rain event that caused weed seeds and
Fusarium spp. to enter the plots. This study suggests, in the absence of
fumigation or solarization, yield losses of at least 37 percent. 
Compared to the most effective fumigation treatments, yield losses would
be 58 percent.  If solarization is feasible and used, yield losses would
be less. (McSorley and Wang, 2004)

Chrysanthemum propagative material must be certified to be free of
certain pests in order to ship to certain states and countries.  In
particular the material must not be contaminated with burrowing,
reniform, and cyst nematodes.  The propagative material must also be
free from other pathogens and pests. Contamination with these pests
could cause losses. 

Hawaii

In anthurium production, it is estimated that without metam sodium,
yield losses would exceed 50 percent.  Eventual loss of farms and/or the
industry is possible due to the lack of alternatives (Kawate and
Tarutani, 2005).

ECONOMIC BENEFITS

According to the USDA NASS Floriculture Crops 2005 Summary, in 2005 the
floriculture industry was valued at $5.36 billion.  Two sectors of the
floriculture industry, bedding and garden plants, accounted for
approximately 51 percent of that value or $2.68 billion.  In terms of
the benefits of fumigant use, there is ample evidence of that fumigant
use increases yield, quality and production especially when a formerly
untreated area is treated for a particular pest.  However, there is very
little data available to conduct a thorough analysis of the impacts of
substituting one fumigant pest control alternative for another on an
existing site.  The data that is available suggests that yield and
quality impacts due to the unavailability of a particular fumigant for a
given industry would result in significant losses to the industry.  This
is especially significant for the propagative sector because for
example, an estimated yield loss of 50 percent to seedling stock could
result in exponential losses to grower future revenues if the current
control alternatives were not available.  This would result in a
combination of direct revenue losses due to adverse impacts on yield and
quality resulting in unviable or unmarketable stock because of pest
infestation.  Many of the yield losses cited in this document estimate
losses in yield alone ranging from 40-60 percent if alternative fumigant
controls are not effective.  Some alternatives such as solarisation are
promising but the transition costs are high and effectiveness is greatly
influenced by weather conditions.  

According to a document submitted by the California Cut Flowers
Association, the Society of American Florists and the Caladium growers
of Florida for the 2003 methyl bromide critical use exemption request
that was produced by the International Labour Organization (ILO) –
Sectoral Activities Committee, US producers are currently suffering from
competition from Central and South American producers who are not
subject to the methyl bromide phaseout because of their developing
country status and from lower production and labor costs.  The US is one
of the largest import markets for cut flowers and foliage worldwide
according to the ILO report, second only to Germany.  To supply US
demand, many US producers have resorted to producing their product
overseas where there are fewer restrictions and production costs are
lower.  The fumigants not only increase yields, quality and production
but also result in lower production costs such as reducing hand labor or
increasing technological inputs.  In addition, fumigants allow producers
to maintain US floriculture industry jobs.  This is important because US
producers are facing increased competition from producers with lower
production and labor costs and less stringent environmental standards.  

The agency is requesting information that will assist with the
determination of benefits of fumigant use including the cost of the
different fumigant controls.  Data are needed that can be used to
measure changes in yield, cost of alternative controls and changes in
the cost of production for the various types of floriculture production.
 This would include crop budgets or enterprise budgets that present
estimates of variable and fixed  production costs including, alternative
fumigant control costs, cultural controls costs such as additional hand
labor or material costs, estimated yield losses if the fumigant of
choice were not available, variable production costs including labor and
material inputs as well as gross and net revenues and other economic
information that would be useful to measure the impact to net revenue
for different sectors of the floriculture industry that may have to
apply buffer zones in open fields or capture fumigant off-gassing to
mitigate risk impacts.

Limitations to assessment

This document attempts to characterize the use of fumigants in the
floriculture industry.  Due to a lack of information to adequately
estimate the impacts to the industry, a quantified assessment of the
benefits provided by the soil fumigants in the production of ornamentals
is not presented.  The following are limitations of this analysis:

Social benefits of pesticide use accrue to several groups, e.g.,
ornamental producers and consumers of ornamentals.  This document
attempts to describe qualitatively the benefits of fumigant use from the
perspective of ornamental producers, and does not quantify economic
impacts for the floriculture industry on other related entities due to
limited information.

The assessment does not account for transition to new agronomic
practices such as a conversion to greenhouse production, introduction of
new growing areas, or the introduction of newer as yet unregistered
fumigants.  

Due to limited information, this assessment does not use partial budget
analyses to estimate potential benefits to the industry but rather
attempts to characterize the industry in terms of value by market
segment, production methods and fumigant control alternatives and their
use.  

REFERENCES

Ajwa, H., C. Elmore, and S. Klose, Life After Methyl Bromide.CDPR
Pesticide Use Report Data, 2005

Chase, A., Scientific Adviser CCFC, Personal communication with Nicole
Zinn, December 17, 2004.

Elmore, C., J. Roncoroni, K. Robb, C. Wilen, and H. Ajwa, 2003, Preplant
Pest Production in Ranunculus Production, Proceeding from the 2003
Annual International Research Conference on Methyl Bromide Alternatives
and Emissions Reductions, Web address:    HYPERLINK
"http://www.mbao.org"  www.mbao.org 

Foliage, Floriculture, and Cut Greens.  May 2003.  Florida Agricultural
Statistics Service.  Web address:  http://www.nass.usda.gov/fl

Foliage, Floriculture, and Cut Greens.  July 2004.  Florida Agricultural
Statistics Service.  Web address:  http://www.nass.usda.gov/fl

Gerik, J. S., I. D. Greene, P. Beckman, and C. L. Elmore, 2006, Preplant
Drip-applied Fumigation for Calla Lily Rhizome Nursery, HortTechnology
16(2), p. 297-300

International Labour Organization (ILO) – Sectoral Activities
Committee, Web address:     HYPERLINK
"http://www.ilo.org/public/english/dialogue/sector/papers/ctflower/" 
http://www.ilo.org/public/english/dialogue/sector/papers/ctflower/ 

Kawate, M. and C. Tarutani, Department of Plant and Environmental
Protection Sciences, University of Hawaii, Information submitted to
Metam Sodium Docket OPP-2005-0125, September 12, 2005. 

McSorley, R. and K.-H. Wang., 2003, Fumigant Alternatives to Methyl
Bromide for Managing Nematodes and Weeds in Snapdragon, Proc Fla State
Hort Soc. 

McSorley, R. and K.-H. Wang, 2004, Impact of Soilborne Pest Problems on
Field-Grown Snapdragons, Proc Fla State Hort Soc.

Pennisi, B. and P.A. Thomas, 2005, Cooperative Extension Service,
University of Georgia College of Agriculture and Environmental Sciences:
Foliage Products – An Opportunity for the Georgia Ornamental Industry.

Pizano, M., 2001, Floriculture and the Environment: Growing Flowers
without Methyl Bromide, United Nations Environment Programme.

Romo, M.J., L.K. Hood and R.C. Sloan, SNA Research Conference –Vol.48
– 2003; Production Costs Budgets for Selected Varieties of Cut Flowers
in Mississippi.

Roozen, J., Washington Bulb Company, Application of Metam Sodium is the
Key to Effective Pest Control.   

Schmale, L., 2005, Fumigant Survery, Society of American Florists.

Society of American Florists (SAF), California Cut Flower Commission,
and Florida Floriculture Growers, September 2005, Methyl Bromide
National Management Strategy, Field Grown Ornamentals in Florida and
California, Bulbs, Cut Flowers, Cut Foliage and Propagative Plant
Material.

Strausbaugh, C., 1996, Soil Solarization for Control of Soilborne Pest
Problems, University of Idaho, Web address:    HYPERLINK
"http://www.uidaho.edu/ag/plantdisease/soilsol.htm" 
http://www.uidaho.edu/ag/plantdisease/soilsol.htm 

Tanouye, E.S., President, Hawaii Florists and Shippers Association,
Information submitted to Metam Sodium Docket OPP-2005-0125, September
12, 2005

USDA Census of Agriculture, 2002

USDA ERS, 1999, Table 30—Cut gladioli: Growers, production, and value
of sales, major States, 1991-98,   Web address:    HYPERLINK
"http://usda2.mannlib.cornell.edu/data-sets/specialty/99003/" 
http://usda2.mannlib.cornell.edu/data-sets/specialty/99003/  

USDA ERS, Amber Waves 2004 article – “Volume Production Keeps
Floriculture Prices Low”,   HYPERLINK
"http://www.ers.usda.gov/amberwaves/February04/Findings/VolumeProduction
.htm" 
http://www.ers.usda.gov/amberwaves/February04/Findings/VolumeProduction.
htm    

USDA NASS Floriculture Crops 2005 Summary, April 2006,   HYPERLINK
"http://www.nass.usda.gov/publications/" 
www.nass.usda.gov/publications/ 

USDA NASS Agricultural Chemical Usage 2003 Nursery and Floriculture
Summary, September 2004,   HYPERLINK
"http://www.nass.usda.gov/publications/agriculturalchemical" 
www.nass.usda.gov/publications/agriculturalchemical usage/

APPENDIX A  ORNAMENTAL SPECIES GROWN AND TARGET PESTS  TC "APPENDIX B 
ORNAMENTAL SPECIES GROWN AND TARGET PESTS" \f C \l "1"  

California Species Grown

It is difficult to determine acreage information for cut flowers. 
However, production data for the major cut flower and bulb species grown
is available and estimates of the acreage have been made (See Tables
below).

Table 1.  California Ornamentals - Partial Listing and Estimate of Cut
Flower and Foliage Area Produced in California in 2002  TC "Appendix B
Table 2.  California Ornamentals Partial Listing and Estimate of Cut
Flower and Foliage Area Produced in California in 2002" \f F \l "1"  

Crop	Area (estimate of outdoor field production) - ha	Area1 (estimate of
greenhouse production) – m2

Alstroemeria	8	47,100 (5 ha)

Antirrhinum (snapdragon)	126	164,898 (17 ha)

Aster

57,598 (6 ha)

Calla lily	16

	Carnation	30	21,739 (2 ha)

Chrysanthemum	88	281,023 (28 ha)

Delphinium	22

	Eucalyptus	54

	Gerbera

214,413 (21 ha)

Gypsophila	55

	Iris (Dutch)	18

	Larkspur	6

	Lilium	32	205,959 (21 ha)

Limonium spp.	13

	Lisianthus	13

	Protea	190

	Rose	41	123,557 (12 ha)

Stock (Matthiola)	26

	Wax flower	317

	Other	791	59,177 (6 ha)

Greenhouse misc.	70	278,700 (28 ha)

Field misc.	303

	Cut greens misc.	389

	Total	2609	1,454,164 (145 ha)

Source:  Chase, 2004

1  Area has been provided in m2 but an estimate of the area in ha has
also been included.  Total does not add due to rounding.  

Florida Species Grown

According to the 2002 Census of Agriculture, cut flowers and florist
greens were grown on 3,402 ha (outdoors) and foliage plants were grown
on 1,198 ha (outdoors).  Approximately 2,511 additional ha of cut
flowers, florist greens, and foliage plants were grown indoors (under
glass) (USDA, 2002).

Although it would be useful to have more accurate acreage information
for each species this has been difficult to obtain for several reasons. 
1) There are hundreds of species of cut flowers, foliage, and bulb crops
grown, and often several species are grown in the same field in the same
year.  2) The species grown are constantly changing and fluctuations may
occur at any time.  For example, several years ago sunflowers were not a
major commercial crop in Florida but currently it is a major crop.  3) 
There are no records available that show which crops are grown at any
one time.  Due to the sheer number of species, and the constant
fluctuation in the industry, the acreage of each species is unable to be
determined.  The Table below shows a few of the major crops grown and
the numberof spikes or stems produced, although acreage information was
not available.  This information indicates that gladioli are another
major crop grown in Florida, and would be expected to be grown on more
acreage than some of the other crops.  

The only three cut flower species identified by the Florida Agricultural
Statistics Service are gladioli, lilies and snapdragon.  These are
assumed to have the highest acreage (See Table below for production
information).  These crops have also been identified by the applicant as
using methyl bromide. 

Table 2. Florida Ornamentals - Crop Production for Certain Cut Flower
Species2  TC " Appendix B Table  . Florida Ornamentals - Crop Production
for Certain Cut Flower Species" \f F \l "1"    

	2001	2002	2003

Crop	# of producers	Quantity sold (1000 spikes)1	# of producers	Quantity
sold (1000 spikes)1	# of producers	Quantity sold (1000 spikes)

Gladioli	4	40,331	4	49,581	4	39,444

Snapdragons	5	6,806	4	4,415	4	4,757

Lilies	4	3,031	3	2,257	-	-

Other cut flowers	-	-	9	-	10	-

1 Quantity of lilies sold 1000 stems.

2 This table only includes data for growers with sales over $100,000.

Source: Foliage, Floriculture, and Cut Greens, May 2003, Florida
Agricultural Statistics Service; Foliage, Floriculture, and Cut Greens,
July 2004, Florida Agricultural Statistics Service. 

Using several data sources, a rough estimate of the number of acres of
gladioli grown can be obtained.  The quantity sold, shown in the Table
above, was averaged and divided by an average yield, which was
calculated using data from 1991 to 1998.  This method resulted in
approximately 638 ha of gladioli.  This number does not take into
account the variability in yield in an individual year or if yields have
changed since 1998 (USDA, 1999). 

Table 3. Florida Ornamentals - Other Cut Flower Species Grown in Florida
 TC " Appendix B Table. Florida Ornamentals - Table 11.5 Other Cut
Flower Species Grown in Florida" \f F \l "1"    

Crop	Crop Rotation Limitation

Delphinium	These species are often sensitive to the same insects and
pests as the other cut flower, foliage and bulb species.

Larkspur

	Gerbera

	Lisianthus

	Sunflower

	Aster

	Chrysanthemum

	

Key Pests of Select Cut Flower Species

The following list is not comprehensive, but is intended to demonstrate
the complexity of the industry. In addition to the diseases and
nematodes listed below, there are numerous weed species that are major
problems in cut flower production.  These species include the bulbs,
tubers, or cormlets from a previous crop, yellow nutsedge (Cyperus
esculentus), little mallow (Malva parviflora), and common sow thistle
(Sonchus oleracea).

Table 4.  Diseases and Nematodes of cut flower crops currently
controlled with Methyl Bromide.  TC "Appendix B Table 5.  Diseases and
Nematodes of cut flower crops currently controlled with Methyl Bromide."
\f F \l "1"  

Crop	Key Pests	Scientific name

Antirrhinum	Nematodes

	 Belanolaimus longidorus, Criconomella spp., Dolichodorus
heterocephalus

	Pythium root rot	Pythium irregulare (documented resistance to mefenoxam
is 25-50 percent)

Calla lily	Erwinia soft rot	Erwinia carotovora

	Pythium root rot	Pythium spp. (resistance to mefenoxam suspected to be
widespread

Delphinium	Sclerotinia stem rot	Sclerotinia spp.

Dianthus	Fusarium wilt	Fusarium oxysporum fsp. dianthii

Eustoma	Fusarium wilt, root rot, and stem rot	Fusarium oxysporum, F.
solani, and F. avenaceaum 

Freesia	Fusarium wilt	Fusarium spp.

Gladiolus	Fusarium wilt	Fusarium oxysporum fsp. gladioli

	Stromatinia neck rot	Stromatinia gladioli

Helianthus	Downy mildew	Plasmopara halstedii (this is a soil-borne
pathogen)

Hypericum 	Root knot nematode	Meloidogyne spp.

	Pythium root rot	Pythium spp.

Iris	Fusarium wilt	Fusarium oxysporum fsp. iridis

Larkspur	Sclerotinia stem rot	Sclerotinia sclerotiorum

Liatris spicata	Sclerotinia stem rot	Sclerotinia sclerotiorum

Lilium	Pythium root rot	Pythium spp.

Matthiola	Sclerotinia stem rot	Sclerotinia sclerotiorum

	Xanthomonas leaf spot	Xanthomonas campestris pv. campestris

Ranunculus	Pythium root rot	Pythium spp.

	Xanthomonas leaf spot	Xanthomonas campestris

Similar information was provided in a recent grower education document
(Ajwa, Elmore and Klose).  In addition to the crops described in the
table above, Gerbera was described as susceptible to Sclerotinia stem
rot.    

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