Document ID: EPA-HQ-OPP-2006-0576-0009
Agency: epa
Document Type: Supporting & Related Material
Title: 
Posted Date: 2007-04-11T04:00Z

SEQ CHAPTER \h \r 1 

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

WASHINGTON D.C., 20460

OFFICE OF

PREVENTION, PESTICIDES AND 

TOXIC SUBSTANCES

						

MEMORANDUM

SUBJECT:	Projected Percent Crop Treated for the Fungicide Tetraconazole
on Three Crops: Peanuts, Soybeans, and Sugar Beets.

FROM:	Jihad Alsadek, Economist

Science Information & Analysis Branch

Biological and Economic Analysis Division (7503P)

			

			Richard Michell, Plant Pathologist

			Biological Analysis Branch

			Biological and Economic Analysis Division (7503P)

TO:			Mary Waller, Product Manager

			Fungicide Branch

			Registration Division (7505P)

THRU:	Diann Sims, Chief

			Science Information Analysis Branch

			Biological and Economic Analysis Division (7503P)

			Arnet Jones, Chief

			Biological Analysis Branch

			Biological and Economic Analysis Division (7503P)

PRP Review: November 29, 2006

I.	SUMMARY

	This memorandum provides projected percent crop treated (PPCT) values
for tetraconazole on three crops (peanuts, soybeans, and sugar beets),
as well as the corresponding Federal Register (FR) language.  The
methodology used to produce the estimates is outlined below, along with
the analysis of additional biological information that could impact the
assessments.  The market leader approach is only used with peanuts;
other approaches are used with soybeans and sugar beets.  The registrant
Isa Gro input and expert opinions are used for soybeans, and the sugar
beet regional value is adjusted for a national one.  We have examined
all the relevant data and conclude that it is unlikely that the actual
percent crop treated (PCT) values for tetraconazole on peanuts, soybeans
and sugar beets in the next five years will exceed the PPCTs provided
for tetraconazole on these three crops. Numbers to be used in risk
analysis are shown in table 1.

Table 1. Values to be used in Risk Assessment

Crop	Chronic	Acute

Peanuts	77	88

Soybeans	27	38

Sugar Beets	70	70

II.	FR LANGUAGE

EPA estimates projected percent crop treated (PPCT) for a new pesticide
use by assuming that the percent crop treated (PCT) during the
pesticide’s initial five years of use on a specific use site will not
exceed the average PCT of the market leader (i.e., the one with the
greatest PCT) on that site.

Typically, EPA uses USDA/NASS as the primary source for PCT data.  When
a specific use site is not surveyed by USDA/NASS, EPA uses other sources
including proprietary data and calculates the PCT.  Comparisons are only
made among pesticides of the same pesticide types (i.e., the leading
fungicide on the use site is selected for comparison with the new
fungicide).  The PCTs included in the average may be for the same
pesticide, or for different pesticides, since the same, or different
pesticides, may dominate for each year selected.    This PPCT, based on
the average PCT of the market leader, is appropriate for use in chronic
dietary risk assessment. The method of estimating a PPCT for a new use
of a registered pesticide or a new pesticide produces a high-end
estimate that is unlikely, in most cases, to be exceeded during the
initial five years of actual use.  

The predominant factors that bear on whether the estimated PPCT could be
exceeded are whether new pesticide use or new pesticide is more
efficacious or controls a broader spectrum of pests than the dominant
pesticide; and/or whether there are concerns with pest pressures as
indicated in emergency exemption requests or other readily available
information; and/or other factor based on analysis of additional
information, such as the total crop acreage and the geographical
distribution of the crops and pests.

All information currently available for the predominant factors
mentioned above or relevant to the case in question have been considered
for this chemical, and it is the opinion of BEAD that it is unlikely
that actual PCT for tetraconazole will exceed the PPCT during the next
five years.  

III.	PROJECTIONS BASED ON MARKET LEADER APPROACH

The PPCTs for peanuts are calculated by averaging the PCTs of the
leading fungicide(s) for the three most recent available years.  The
PPCT for sugar beets showed a 55 percent use of tetraconazole as the
market leader for the year 2000, but 2000 USDA/NASS data for the market
leader tetraconazole is registered on sugar beets in seven states
(Colorado, Michigan, Minnesota, Montana, Nebraska, North Dakota, and
Wyoming).  NASS data are adjusted to get the acres treated in each of
the seven states, summing them up, then dividing by the sum of the
planted acres in these same states, and multiplying by 100 to get, on
average, market leader for sugar beets to be used in chronic dietary
risk assessment and acute risk too.

  The PPCTs for soybeans were based on a modified approach which is
described in the following subsection (Modified PPCT Approach for
Soybeans).

Table 2.  Projected Tetraconazole PCT Values for Dietary Risk
Assessments

Crop	Market Leaders	Average

Market Leader	Maximum

Market Leader	Years

Peanuts	Chlorothalonil 	77	88	1991, 1999, 2004

Soybeans	Unknown, but projected to be a triazole and/or strobilurin
fungicide	27	38	Future projection for next 5 years

Sugar Beets	Tetraconazole	70	70	Adjusted for year 2000

Sources:  Based on 1991 to 2004 NASS usage data for peanuts and sugar
beets.  Crop 

Specialists’ usage projections were used for soybeans.

  Market leaders could be the same chemical for all three years or could
be different for each year. 

b  Averaging the available years.

c  The highest observed percent crop treated of the available survey
years.

IV.         Modified PPCT Approach for Soybeans

Due to the recent discovery of a new and important disease on soybeans,
Asian soybean rust, historical information was not considered useful for
estimating a useful PCT for a fungicide market leader on soybeans. 
Another approach was utilized which involved obtaining PCT estimates for
future market leaders from soybean crop specialists.  The estimates were
obtained via a phone call and four list server responses enlisted by
USDA.  The five crop specialists’ PCT estimates for a market leader
ranged from 10 to 38 percent.  For a conservative estimate we utilized
only the maximum projected values provided by each respondent, which
ranged from 15 to 38 percent.  These values translated into average and
maximum PPCT values of 27 and 38 percent, respectively.

The most common factors used by the crop specialists to project the
market leader PCT were: weather patterns; prevailing winds; length of
time crop is in a growth stage that will lead to yield losses, if
infection occurs during this period; cost-effectiveness of treatments;
and market supply/availability limitations.  Some of the specific
examples provided to support their estimates were:

About 21% of the total soybean acreage is in areas where the prevailing
winds and temperature and humidity are generally unfavorable for soybean
rust infection (e.g., KS, ND, NE, SD).  

About 16% of the total soybean acreage doesn’t have the yield
potential to justify the cost of a soybean rust fungicide treatment.

In most years 40% of the soybean acreage is considered to possess a high
risk for soybean rust infection (e.g., IL, IN, OH, AR, eastern MO).

Pesticide distributors are more likely to carry stock of those soybean
rust fungicides that have other labeled uses relevant to area growers
(e.g., wheat  and corn uses in Midwestern states).  Note: The only
alternate crop uses for tetraconazole are sugar beets and peanuts, which
are not prevalent crops in most soybean production areas.

V.	ADDITIONAL FACTORS

Table 3. Biological Analysis of BEAD’s Projected Percent Crop Treated
(PPCT) for Tetraconazole on Three New Crops

NEW USES

[AVG. /MAX. PPCT]	RECENT MARKET LEADER(S) [SAMPLE YEARS]
JUSTIFICATION/COMMENTS	WILL TETRACONAZOLE EXCEED THE PCT LEVELS OF
MARKET LEADER(S)?

Sugar Beets – cercospora leaf spot, 

powdery mildew 

[70/70]	tetraconazole

[2000]	Tetraconazole is the current market leader (55%), and was
previously only registered for use in 7 sugar beet producing states (CO,
MI, MN, MT, NE, ND, WY); based on the 2006 acreage planted, the addition
of 4 states (CA, ID, OR, WA) increases the potential acreage to be
treated by about 18 percent;  if all the planted acreage in these 4
additional states are treated it could bring the PPCT up to about 77%;
based upon the pest information provided in the USDA Crop Profiles it is
not likely that more than 70% of the planted acreage will be treated in
any of the 4 additional states, because the reported total fungicide
usage for these target pests is less than 70%	No

Soybeans – 

Asian soybean rust, 

cercospora, 

frog eye, 

white mold, powdery mildew, septoria, anthracnose

[27/38]	Not applicable	These values seem to be reasonable estimates for
the future market leader(s) when the following factors are considered:  

1] at least 11 active ingredients are currently available and competing
for the Asian soybean rust control market on the approximately 75
million acres grown; 

2] treatments are only warranted when weather conditions conducive to
disease development occur during the soybean bloom and/or pod fill
stages; 

3] in any given year the probability of a national epidemic which
results in the need for most of the US acreage grown in the 31 soybean
producing states being treated is low, because it would be dependent
upon the widespread occurrence of unusual weather patterns during the
critical crop growth stages; 

4] The proposed labeling allows for up to two applications per year,
which if it occurs will reduce stocks and therefore reduce the total
acreage capable of being treated; Some of the crop specialists projected
that up to 30 - 40% of the acreage in their state may be treated twice.

5] the registrant stated that only one tetraconazole product will be
marketed for the soybean use because the chemical is still under patent,
which would appear to limit the amount likely to be available throughout
the US due to supply limitations and surplus stock concerns if an
epidemic does not occur;

6] The registrant (Isa Gro), per a personal phone call on November 16,
2006, stated that although they projected they might be able to treat as
much as 5.38% of the crop if an epidemic occurred; they felt it would be
impossible to supply enough tetraconazole to treat 10% of the crop
anytime within the next 5 years.

7] Since the disease organism is not considered cold-hardy, each growing
season the disease must start its northward movement from Mexico and/or
extreme southern United States locations.  Accordingly, the northward
disease spread each year and the specific states impacted is dependent
upon wind speed and direction during humid and moderate temperature
weather.  

8] EPA has approved a wide range of active ingredients and products that
can be available to growers.  This effort was initiated because of
national concern that the supply of fungicides would not be adequate in
the case of a soybean rust epidemic.  This involved granting numerous
states permission to use seven active ingredients via Section 18
quarantine emergency exemptions, in addition to the four active
ingredients already available via Section 3 registrations.

9] Based on yields obtained in recent soybean rust efficacy studies
conducted in the US and other countries the triazole and strobilurin
fungicide classes generally seem to be the most efficacious groups of
fungicides to use (Fungicide & Nematicide Tests – Special Section on
Asian Soybean Rust Reports;   HYPERLINK
"http://www.apsnet.org/online/FNtests/" 
http://www.apsnet.org/online/FNtests/ ).  Most crop specialists predict
combinations of these two types of fungicides will be used by many
growers.

10] Since the competing fungicide tebuconazole is reportedly among the
least expensive fungicides, as well as one of the most effective
triazole fungicides, it is generally considered by crop specialists to
be the triazole fungicide of choice.  Since there are multiple products
(alone and in combinations with other fungicides) being sold by
different companies reasonable stocks are expected to be available in
most soybean production areas. 

11] Crop specialists projected that the maximum US soybean acreage to be
treated with a fungicide, if an epidemic occurred, would range from
35-65 percent (average = 54%).  Therefore if one of the eleven active
ingredients available were able to attain a 50% market share this would
only result in a maximum of 32.5% of the crop being treated with any one
fungicide.  BEAD contends that this level of market share is rarely
achieved when a number of competitive active ingredients are available. 
	No,  plus the likelihood of an epidemic although uncertain is thought
to be low

Peanuts – 

early leaf spot, late leaf spot, 

web blotch, 

rust [77/88]	chlorothalonil [ 1991, 1999, 2004]	The market leader
chlorothalonil is  typically inexpensive and is used mainly for control
of the same pests that are claimed on the proposed tetraconazole label
plus the common and important disease white mold (southern stem rot);
chlorothalonil is alternated with various systemic fungicides to delay
the development of resistant pest strains; the introduction of the
systemic fungicide tetraconazole will not likely affect
chlorothalonil’s current usage, but it is expected to share the
existing systemic fungicide market	No

VI. CONCLUSIONS/RECOMMENDATIONS

BEAD recommends that the given average PPCTs be used in the chronic
dietary risk assessment for tetraconazole, and the maximum PPCTs for
acute risk assessment.  BEAD has considered all relevant information and
believes it is unlikely that the above PPCTs will be exceeded during the
next five years for peanuts, soybeans, and sugar beets.

VII. References:

Typically, EPA uses USDA/NASS as the source for raw PCT data because it
is publicly available and does not have to be calculated from available
data sources.  When a specific use site is not surveyed by USDA/NASS,
EPA uses proprietary data and calculates the estimated PCT.

Agricultural Chemical Usage, 1990 Field Crops Summary, May 1991

Agricultural Chemical Usage, 1998 Field Crops Summary, May 1999

Agricultural Chemical Usage, 1999 Field Crops Summary, May 2000

Agricultural Chemical Usage, 2004 Field Crops Summary, May 2005

USDA, 1999, Crop Profile for Sugar Beet in California.  

	  HYPERLINK
"http://www.ipmcenters.org/cropprofiles/docs/casugarbeets.html" 
http://www.ipmcenters.org/cropprofiles/docs/casugarbeets.html 

USDA, 2000. Crop Profile for Sugar Beet in Idaho.  

	  HYPERLINK
"http://www.ipmcenters.org/cropprofiles/docs/IDsugarbeets.html" 
http://www.ipmcenters.org/cropprofiles/docs/IDsugarbeets.html 

USDA, 1999, Crop Profile for Sugar Beet in Oregon.  

	  HYPERLINK
"http://www.ipmcenters.org/cropprofiles/docs/orsugarbeets.html" 
http://www.ipmcenters.org/cropprofiles/docs/orsugarbeets.html 

USDA, 2001, Crop Profile for Sugar Beet in Washington.  

	  HYPERLINK
"http://www.ipmcenters.org/cropprofiles/docs/WAsugarbeets.html" 
http://www.ipmcenters.org/cropprofiles/docs/WAsugarbeets.html 

cc:  	Lisa Jones

	Thomas Bloem 

	Dana Spatz