UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

WASHINGTON, D.C. 20460      

	OFFICE OF PREVENTION, PESTICIDE

	AND TOXIC SUBSTANCES

	

  SEQ CHAPTER \h \r 1 MEMORANDUM

Date:  6/12/2008

SUBJECT:  Ingredient:  Fenbuconazole

		Title:  Petition for Registration for Use on Pepper, Bushberry
Subgroup (13-B), and Cranberry.  Summary of Analytical Chemistry and
Residue Data.

  

 

PC Code:  129011 	 DP #s:  313752, 313753, 345256, 351444  

Decision No.:  354084, 354085, 383131, 383432              	
Registration No.:  62719-421 

Petition Nos.:  9E5041, 1E6252, and 7E7256	 Regulatory Action:  Section
3 

Risk Assessment Type:  None 	 Case No.:  None 

TXR No.: None	 CAS No.:  114369-43-6

MRID No.:   44690600, 44690601, 45268401,

                     45296000, 45296001, 47215801 	 40 CFR:  180.480

		              							

	          	

FROM:  	Douglas Dotson, Ph.D., Chemist

	Registration Action Branch 2

	Health Effects Division (7509P)  SEQ CHAPTER \h \r 1 		

		

THROUGH:	William Drew, Chemist

		Richard Loranger, Ph.D., Senior Scientist

	Registration Action Branch 2

Health Effects Division (7509P)  SEQ CHAPTER \h \r 1 	

		

TO:		Barbara Madden/Shaja Brothers, RIMUERB

		and

		John Bazuin/Tony Kish, RM 22, Fungicide Branch

		Registration Division (7505P)

This document was originally prepared under contract by Dynamac
Corporation (1910 Sedwick Road, Building 100, Suite B, Durham NC 27713;
submitted 1/23/2008).  The document has been reviewed by the Health
Effects Division (HED) and revised to reflect current Office of
Pesticide Programs (OPP) policies.		  SEQ CHAPTER \h \r 1   SEQ CHAPTER
\h \r 1 

Executive Summary

Fenbuconazole
[α-[2-(4-chlorophenyl)ethyl]-α-phenyl-1H-1,2,4-triazole-1-propanenitri
le] is a broad spectrum, triazole-type fungicide that acts by inhibiting
sterol biosynthesis in fungi.  It is formulated as a flowable
concentrate (FlC) or wettable powder (WP), and is currently registered
for use on the following food/feed crops:  cranberries, the Bushberry
Subgroup (Crop Subgroup 13-B), almonds, apples, bananas, citrus fruits,
pecans, peanuts, stone fruits, sugar beets, and wheat.  Permanent
tolerances are established for the combined residues of fenbuconazole
and its lactone metabolites, RH-9129 and RH-9130 [trans- or
cis-5-(4-chlorophenyl)dihydro-3-phenyl-3-(1H-1,2,4-triazol-1-ylmethyl)-2
(3H)-furanone], expressed as parent in/on plant commodities at levels
ranging from 0.05 ppm in/on almonds and pecans to 40 ppm in citrus oil
[40 CFR §180.553(a)].  Permanent tolerances have also been established
at 0.05 ppm for the combined residues in meat byproducts of cattle,
goats, horses, and sheep.

A tolerance of 0.3 ppm is currently in effect for Crop Subgroup 13-B,
the Bushberry Subgroup, and a tolerance of 0.5 ppm is in effect for
cranberries.  These tolerances were recommended by HED in a human health
risk assessment performed for several commodities (Memo, D316607, M.
Collantes, et al., 8/3/2006).  Although the field trial data for
blueberries and cranberries were reviewed and a residue chemistry
summary document was prepared, the summary document was never finalized.
 The human health risk assessment referenced above was prepared,
however.  The bushberry registration was made conditional, and the
registrant was asked to submit two additional field trials for
blueberries.  The blueberry and cranberry field trial data are being
included in this document and the associated human health risk
assessment (Memo, D344351, D. Dotson, 6/12/2008).  

A 75% WP formulation of fenbuconazole (INDAR® 75WSP; EPA Reg, No
62719-421) is currently registered to Dow AgroSciences for use on a
variety of fruit and nut crops, sugar beets, and wheat.  Interregional
Research Project No. 4 (IR-4) has submitted a petition proposing the use
of this formulation on peppers for control of Cercospora leafspot and
powdery mildew.  The proposed use is for multiple broadcast foliar
applications to peppers at up to 0.188 lb ai/A/application with a
minimum retreatment interval (RTI) of 10 days, for a maximum of 0.75 lb
ai/A/season.  Applications may be made using either ground or aerial
equipment, although use of aerial equipment is not recommended.  Ground
applications should be made in a minimum volume of 30 gal/A, and can
include the use of a non-ionic surfactant.  The minimum preharvest
interval (PHI) is 7 days for peppers.  In conjunction with this use,
IR-4 is proposing the following permanent tolerance for the combined
residues of fenbuconazole and its lactone metabolites, RH-9129 and
RH-9130, expressed as fenbuconazole:

Pepper	0.4 ppm

The qualitative nature of fenbuconazole residues in plants is adequately
understood based upon the adequate peach, peanut, sugar beet, and wheat
metabolism studies.  The residues of concern in/on peppers, bushberries,
and cranberries, for purposes of both tolerance expression and risk
assessment, are fenbuconazole and its lactone metabolites, RH-9129 and
RH-9130.  

The crop uses being proposed in this petition do not include any
regulated livestock feedstuffs.  As a result, issues pertaining to
livestock metabolism, analytical methods, storage stability in animal
commodities, and residues in livestock commodities are not relevant to
the current petitions.

A GC/NPD method, 34-90-47R, is currently available for enforcing
tolerances of fenbuconazole and its two lactone metabolites (RH-9129 and
RH-9130) in/on stone fruits, and a slightly modified version of this
method was demonstrated to be adequate for determining residues in
peppers.  For this method, the validated limit of quantitation (LOQ) for
residues in/on peppers is 0.01 ppm for each analyte, for a combined LOQ
of 0.03 ppm.  The statistically calculated limit of detection (LOD) was
0.003-0.004 ppm for each analyte.  The method was adequately validated
in conjunction with the pepper field trials.

Method 34-90-47R was demonstrated to be adequate for determining
residues in bushberries and cranberries.  The validated LOQ is 0.01 ppm
for each analyte in/on berries, for a combined LOQ of 0.03 ppm.  The LOD
was not reported.  As currently written, the method expresses residues
of RH-9129 and RH-9130 in terms of the individual analytes.  To
calculate combined residues (expressed as parent), the metabolites must
be multiplied by the molecular weight conversion factor of 0.95x.  The
above method was adequately validated in conjunction with the blueberry
and cranberry field trials.  The average method recoveries were 89-106%
for the three analytes.

Adequate storage stability data were submitted with the pepper field
trials, indicating that fenbuconazole and its lactone metabolites are
stable in peppers at <-10ºC for up to 16.6 months of storage.  These
data adequately support the maximum duration of frozen storage (16.4
months) from the pepper field trials. 

The available storage stability data indicate that residues of
fenbuconazole, RH-9129, and RH-9130 are stable in frozen storage for at
least 8 months in blueberries and 5.5 months in cranberries.  In the
current field trials, the maximum frozen storage durations were
approximately 8 months for blueberries and approximately 5 months for
cranberries.

Adequate field trial data are available supporting the proposed use on
peppers.  Following the last of four or five broadcast foliar
applications of fenbuconazole (WP) at rates totaling 0.66-0.84 lb
ai/A/season (0.9-1.1x rates), the combined residues of fenbuconazole,
RH-9129, and RH-9130 were 0.05-0.23 ppm in/on 18 samples of bell and
non-bell peppers harvested 6-7 days after the last treatment (DAT). 
Average combined residues were 0.14 ppm in/on peppers at ~7 DAT, and
residues were shown to decline at longer post-treatment intervals.  No
processing studies are required for this petition, as there are no
regulated processed commodities associated with peppers.

The available cranberry data are adequate and support the use of up to
five foliar applications of fenbuconazole (WP or FlC) at up to 0.188 lb
ai/A/application, for a maximum seasonal rate of 0.94 lb ai/A.  The data
support the label PHI of 30 days, a minimum RTI of 10 days, and the use
of a non-ionic surfactant in the spray mix.  In the five cranberry field
trials, the combined residues of fenbuconazole and its lactone
metabolites were 0.09-0.49 ppm in/on 10 samples harvested 25-28 DAT, and
average combined residues were 0.199 ppm.

Nine of the ten submitted blueberry field trials are adequate.  Eight
acceptable field trials are needed for blueberries.  Data from the
blueberry field trials support the use of up to five foliar applications
of fenbuconazole (WP or FlC) to bushberries at up to 0.094 lb
ai/A/application, for a maximum seasonal rate of 0.47 lb ai/A.  The data
support the label PHI of 30 days, a minimum RTI of 10 days, and the use
of a non-ionic surfactant in the spray mix.  The combined residues of
fenbuconazole, RH-9129, and RH-9130 (expressed as parent) were
<0.03-0.24 ppm in/on 18 samples harvested 25-35 DAT and average combined
residues were 0.083 ppm.

Adequate confined rotational crop studies are available and indicate
that the metabolite profile in rotational crops is similar to the
metabolite profile in primary crops.  The rotational crop restrictions
on the current label for the 75% WP are adequate.  No limited rotational
crop field trials or rotational crop tolerances are required.

  SEQ CHAPTER \h \r 1 Regulatory Recommendations and Residue Chemistry
Deficiencies

In its February 7, 2006 risk assessment for 1,2,4-triazole and its
metabolites, triazole alanine and triazole acetic acid (M. Doherty et
al, DP# 322215), HED recommended that resolution of various issues be
made a condition of registration for new uses of triazole-derivative
fungicides and for new active ingredients which contain the
1,2,4-triazole ring.  The requirement for a chronic
toxicity/oncogenicity study in male rats and female mice in the 2/7/2006
memo was later modified by HED to a 1-year chronic study in male and
female rats (D321328, Kit Farwell, 5/10/2006).  The other conditions of
registration that were listed in the 2/7/2006 risk assessment have not
been satisfied and are conditions for the use of fenbuconazole on
peppers.

No major deficiencies were noted in the subject petition that would
preclude establishing a permanent tolerance for fenbuconazole on
peppers.  However, an error was noted in the proposed use directions and
no data were provided on residues of 1,2,4-triazole, triazole alanine,
or triazole acetic acid.  These deficiencies (see below) need to be
resolved as a condition of registration.  HED recommends establishing a
permanent tolerance with a conditional registration for the combined
residues of fenbuconazole and Metabolites RH-9129 and RH-9130, expressed
as parent, in/on pepper at 0.40 ppm.

	•	The use directions contain an error in the single use rate.  The
single application rate is specified as 2-4 oz. of product (75%
WP)/A/application, which is equivalent to 0.094-0.188 lb
ai/A/application.  However, in terms of lb ai/A, the directions indicate
that the rate is 0.10-0.167 lb ai/A.  This error should be corrected. 
The data will support a maximum single use rate of up to 0.188 lb ai/A.

	•	Although adequate residue data were provided on fenbuconazole and
its regulated metabolites RH-9129 and RH-9130, none of the samples were
analyzed for residues of triazole, triazole alanine, or triazole acetic
acid, as required by current Agency guidance (Memo, D327788, M. Doherty,
4/25/2006).  

For Crop Subgroup 13-B, the Bushberry Subgroup, HED is in agreement with
the registrant that adequate field trials have been submitted.  In order
for the conditional registration to be converted to unconditional, the
data for the triazole metabolites, discussed above, should be submitted
and be considered to be adequate by the Agency.

Deficiencies Cited in Previous Actions

In its risk assessment of 8/3/2006, HED noted several data deficiencies
(Memo, D316607, M. Collantes, et al, 8/3/2006).  Dow AgroSciences
addressed some of these deficiencies in two letters that were submitted
to the Agency (3/30/2007 and 7/12/2007).  HED has evaluated Dow’s
responses to the data deficiencies.

HED requested that Dow submit updated analytical reference standards for
fenbuconazole, RH-9129, and RH-9130.  These standards have been
submitted.

HED requested that Dow submit an apple processing study.  This study has
been submitted; however, it has not been reviewed by HED.

HED requested that Dow submit the results of two additional blueberry
field trial studies.  As discussed in this summary document, two
acceptable studies were submitted.

HED requested that Dow submit the results of 20 field trials performed
on wheat forage and 12 field trials performed on wheat hay.  Dow has not
submitted the requested data.  Dow’s representative responded by
stating that Dow is of the opinion that the 8 field trials that were
performed for each commodity should be sufficient.  The OPPTS Series 860
Guidelines recommend that 20 field trials be performed for each of these
commodities.  As stated above, Dow performed 8 trials for each.  The
forage trials were performed at a 2x application rate.  Dow’s
representative gave 3 reasons as to why Dow felt that the original 8
trials should be satisfactory:  (1) the maximum application rates used
in the 8 trials were the same or lower than the currently labeled ones,
(2) the cattle dietary intake of fenbuconazole residues through
ingestion of wheat forage and hay is insignificant because very little
wheat is treated with fenbuconazole (compared to other commodities), and
because wheat forage and hay make up a small fraction of cattles’
diets, and (3) based on the results of the ruminant metabolism study,
the secondary residues in cattle would be very low.  Most forage and hay
used for cattle feed is grown in the Southern United States.  The field
trials were performed in Ohio, Michigan, Minnesota, North Dakota, South
Dakota, Nebraska, Montana, and Wyoming.  Most of these states are more
northern.  HED continues to request that twenty field trials be
performed for forage and 12 trials be performed for hay.  HED bases this
request on the following three factors:  1)  considerably fewer trials
were performed than are generally needed, 2)  all of the forage trials
were performed at a 2x rate, and 3)  the trials were not performed in
major feedstuff producing geographical regions.

HED requested that Dow submit another citrus processing study.  In the
original study, samples were not analyzed within the time interval for
which residues have been demonstrated to be stable.  Fenbuconazole
residues have been shown to be stable in fruit for 8 months and in oil
and dried pulp for 12 months.  In the citrus processing study, the
maximum storage durations were 24 months for fruit and 39 months for oil
and dried pulp.  Rather than performing another citrus processing study,
Dow requested that the Agency translate peach and apple storage
stability data to the processed citrus fractions.  In peaches and
apples, very little decay occurred in residues of fenbuconazole and the
metabolites RH-9129 and RH-9130 over a period of 54 months (4.5 years)
and 36 months, respectively.  In peaches, percent recovery after 54
months for the 3 analytes is as follows:  fenbuconazole (94%), RH-9129
(91%), and RH-9130 (87%).  In apples, percent recovery after 36 months
for the 3 analytes is as follows:  fenbuconazole (103%), RH-9129 (97%),
and RH-9130 (93%).  The available storage stability data for peaches,
apples, and processed citrus fractions demonstrate to the satisfaction
of HED that residues of fenbuconazole, RH-9129, and RH-9130, would be
stable in citrus fruit for 24 months and oil and dried pulp for 39
months.

Finally, HED informed Dow that the analytical method proposed for
enforcement of tolerances on animal commodities (GC/NPD Method TR
34-94-142), must undergo a tolerance method validation.  BEAD/ACB has
not performed the validation.

Background

Fenbuconazole is a broad spectrum, triazole-type fungicide used to
control various fungal diseases.  It acts by inhibiting sterol
biosynthesis in fungi (MOA Group 3).  Fenbuconazole is formulated as a 2
lb/gal FlC or 75% WP and is registered to Dow AgroSciences, LLC, for use
on almonds, apples, bananas, bushberries, citrus fruits, cranberries,
pecans, peanuts, stone fruits, sugar beets, and wheat.

IR-4 submitted a petition proposing the use of fenbuconazole, formulated
as a 75% WP (Indar® 75WSP; EPA Reg. No. 62719-421), on peppers for the
control of Cercospora leaf spot and powdery mildew.   The nomenclature
of fenbuconazole and its regulated metabolites is presented in Table 1,
and the physicochemical properties of fenbuconazole are presented in
Table 2.

On behalf of the Blueberry Research Council and the Cranberry Institute,
IR-4 submitted tolerance petitions PP#9E5041 and PP#1E6252 supporting
the use of fenbuconazole, formulated as a 75% WP, on various bushberries
and cranberries for control of mummyberry disease, Septoria leaf spot,
anthracnose leaf spot, cottonball disease, and fruit rot diseases.  In
conjunction with these uses, the petitioner proposed the establishment
of permanent tolerances for the combined residues of fenbuconazole and
its metabolites RH-9129 and RH-9130, expressed as fenbuconazole, in/on
cranberries and Crop Subgroup 13-B, the Bushberry Subgroup.  The
tolerances are established at 0.3 ppm for bushberries and 0.5 ppm for
cranberries.

Table 1.	Fenbuconazole Nomenclature. tc "TABLE A.1.	Test Compound
Nomenclature" 

Compound

	



Common name	Fenbuconazole

Company experimental name	RH-7592

IUPAC name	

(RS)-4-(4-chlorophenyl)-2-phenyl-2-(1H-1,2,4-triazol-1-ylmethyl)butyroni
trile

CAS name	

α-[2-(4-chlorophenyl)ethyl]-α-phenyl-1H-1,2,4-triazole-1-propanenitril
e

CAS #	114369-43-6

End-use product/EP	75% WP (Indar® 75 WSP Fungicide, EPA Reg. No.
62719-421)

Metabolites	 cis and trans isomers



Common name	

cis and trans lactone metabolites; Lactones A and B



Company experimental names	

RH-9129 and RH-9130



IUPAC names	

(3R,5R) or
(3S,5R)-5-(4-chlorophenyl)-3-phenyl-3-(1H-1,2,4-triazol-1-ylmethyl)dihyd
rofuran-2(3H)-one



CAS names	

trans- or
cis-5-(4-chlorophenyl)dihydro-3-phenyl-3-(1H-1,2,4-triazol-1-ylmethyl)-2
(3H)-furanone

CAS #	cis isomer, 146887-38-9; trans isomer, 146887-37-8



Table 2.	Physicochemical Properties of the Technical Grade
Fenbuconazole.

Parameter	Value	Reference

Melting point/range	

127(C	

DP# D310959, S. Oonnithan, 7/25/2006

pH	

not available

	Density (20ºC)	

0.50 g/mL

	Water solubility (mg/L at 22°C)	

3.8 mg/L

	Solvent solubility (g/L at 25°C)	

Acetonitrile: 231	

Cyclohexanone: 445

ethyl alcohol: 39 

1-octanol: 13	

aromatic 200: 77 ethyl acetate: 159 heptane: 1.0

	Vapor pressure at 25°C	

0.37 (10-7 mm Hg (4.9 ( 10-6Pa)

	Dissociation constant (pKa)	

Not expected to dissociate in water

	Octanol/water partition coefficient Log(KOW)	

3.02 ± 0.08

	UV/visible absorption spectrum	λ max (nm)	ε (L(mol-1(cm-1)

    196		    53,000 

    262		         750

    268		         740

    275		         480

	

860.1200  Directions for Use

There are currently three fenbuconazole end-use products (EPs)
registered to Dow AgroSciences for use in the U.S. on food/feed crops. 
These EPs are marketed under the trade names Enable™ and Indar™ and
include a 2 lb/gal FlC and two 75% WPs.  IR-4 is proposing the use of a
75% WP (Indar™ 75 WSP; EPA Reg. No. 62719-421) on peppers.  An example
label was provided for the 75% WP, and the proposed use directions are
summarized below in Table 3.

A 75% WP formulation is registered for use on bushberries and
cranberries.  The use directions are summarized in Table 3.

Table 3.	Summary of Directions for Use of Fenbuconazole.

Applic. Timing, Type, and Equip. 1	Formulation

[EPA Reg. No.]	Applic. Rate 

(lb ai/A)	Max. No. Applic. per Season	Max. Seasonal Applic. Rate

(lb ai/A)	PHI

(days)	Use Directions and Limitations 2

Peppers (Including but not limited to: bell, chili, cooking, non-bell,
pimento and sweet)

Broadcast foliar applications to peppers when disease first appears

Ground or aerial equipment	75% WP

[62719-421]	0.188 3	NS	0.75	7	Apply in a minimum of 30 gal/A, using
ground equipment.

The minimum RTI is 10-14 days. Use of NIS is recommended.

Bushberry Subgroup (including blueberry, currant, elderberry, 

gooseberry, and huckleberry)

Broadcast foliar applications beginning at bud break (green tip) through
fruit development.

Ground or aerial equipment

	75% WP

[62719-421]	0.094	5	0.47	30	A minimum retreatment interval of 10 days
specified.

Do apply through any type of irrigation system.

For ground and aerial applications, apply in a minimum volume of 10 and
20 gal/A, respectively.

A non-ionic surfactant should be used in the spray mix.

Cranberries

Broadcast foliar applications beginning when 50% of shoots show ¼ inch
of new growth, through fruit development.

Ground or aerial equipment

	75% WP

[62719-421]	0.188	5	0.94	30	A minimum retreatment interval of 7 days is
specified.

Do apply through any type of irrigation system.

For aerial applications, apply in a minimum volume of 10 gal/A.

A non-ionic surfactant should be used in the spray mix.

1	Do not apply through any type of irrigation system.  Although
application using aerial equipment is permitted, ground application is
recommended.

2	Rotational crop restrictions:  the minimum plant-back interval is 35
days when the last application of the product is <0.188 lb ai/A, and 210
days when the last application of the product is 0.2-1 lb ai/A.

3	The maximum use rate is based on the use of 4 oz
product/acre/application.

NS = not specified.

Conclusions.  The use directions are adequate to allow for evaluation of
the residue data relative to the proposed use.  The available field
trial data on peppers are adequate and support the proposed use;
however, the maximum use rate on the label needs to be corrected.  The
label specifies a maximum application rate of 4 oz product/A or 0.167 lb
ai/A; however, 4 oz product/A is actually equivalent to 0.188 lb ai/A. 
Although the single application rates used in the field trials were
~0.167 lb ai/A (0.9x rate), the residue data from these tests support
the 0.188 lb ai/A/application rate.

The available blueberry and cranberry field trial data support the label
use directions.  Although only the WP formulation is registered for use
on bushberries and cranberries, the field trial data using the 75% WP
also support the use of FlC and dry flowable (DF) formulations.

860.1300 Nature of the Residue - Plants

MARC Decision memo (N. Dodd and W. Wassell, 3/9/94)

Memo, D200171, N. Dodd, 4/5/94

Memo, D241864, G. Otakie, 3/30/06

Adequate studies are available depicting the metabolism of
[14C]fenbuconazole in peaches, peanuts, and wheat.  Results from these
studies were previously summarized for review by the HED Metabolism
Committee (Memo, N. Dodd and W. Wassell, 12/10/93).

In the peach metabolism study, peach trees received five foliar
applications of either [phenyl-14C] or [triazolyl-14C] fenbuconazole
(6.8% emulsifiable concentrate (EC)) at rates totaling approximately 1
lb ai/A, and whole fruit were sampled at 22 days after the last
application.  For both 14C-labels, the major residues identified in
fruit were fenbuconazole (16-45% TRR) and the lactone metabolite RH-9129
(4-14% TRR).  Triazole alanine (RH-3968, 48% TRR) and triazole acetic
acid (RH-4098, 7% TRR) were also identified in the
[triazolyl-14C]-labeled fruit, and additional analysis by the petitioner
detected only minor amounts of glucose conjugates of RH-4911 (4.4% TRR).

In the peanut metabolism study, vine and nutmeat samples were collected
28 days after the last of four foliar applications of either
[phenyl-14C] or [triazolyl-14C] fenbuconazole (6.8% EC) at one-month
intervals, at rates totaling ~2 lb ai/A.  For both 14C-labels, the major
residues in vines were parent (45-54% TRR), RH-9129 (4-5% TRR), RH-6467
(8-10% TRR), and the glucose conjugates of 4911 (18-19% TRR).  Triazole
alanine (7% TRR) was also identified in the [triazolyl-14C]-labeled
vines.  The major residues in nutmeats were triazole alanine (88% TRR)
from the [triazolyl-14C]-label and the glucose conjugate of 4911 (29%
TRR) from the [phenyl-14C] label.

In the wheat metabolism study, plants received two foliar applications,
8 days apart, of either [Phenyl-14C] or [Triazolyl-14C] fenbuconazole
(7% EC) at rates totaling ~0.72 lb ai/A.  Samples of straw, chaff, and
grain were collected at 39 days after the second application.  For both
14C-labels, the major residues in straw were parent (65% TRR), RH-9129
(8% TRR), and RH-6467 (3-5% TRR).  The glucose conjugates of 4911 (3%
TRR) were only a minor component of wheat straw.  The major residue
identified in [phenyl-14C]-labeled grain was parent (12.5% TRR), and the
major residues identified in [triazolyl-14C]-labeled grain were triazole
alanine (48% TRR) and triazole acetic acid (20% TRR).

Based on the above metabolism studies, the HED Metabolism Committee
concluded that the residues of concern for uses on stone fruit, wheat,
pecans, bananas, apples, and almonds are fenbuconazole and its lactone
metabolites RH-9129 and RH-9130 (N. Dodd and W. Wassell, 3/9/94).  Based
on differences in metabolism between the three crops, the Committee also
concluded that a metabolism study would be required for any crop not
botanically similar to the crops for which metabolism studies are
available.

The conclusion regarding the residues of concern was contingent upon the
petitioner providing data showing that RH-4911 is only a minor residue
in these crops.  The petitioner subsequently fulfilled this requirement
by providing data from the wheat and peach metabolism studies showing
that conjugates of RH-4911 accounted for <5% of the TRR in peaches and
wheat straw (D200171, N. Dodd, 4/5/94).

In addition, the Metabolism Committee noted that the iminolactone
metabolite (RH-6468) would also be included de facto in the residues of
concern, as the petitioner has indicated that this compound is converted
to the lactones by the analytical methodology.

In addition to the above metabolism studies, an adequate sugar beet
metabolism study was reviewed (D241864, 44343303.der) in conjunction
with a petition for use on sugar beets.  In this study, [phenyl-14C]
fenbuconazole (EC) was applied to sugar beets as three foliar
applications at 39, 103, and 183 days after planting, at rates totaling
3 lb ai/A, and samples of tops and roots were collected 7 days after the
final application.  The major residue identified in both tops and roots
was parent (83-91% TRR), along with minor amounts of the lactone
metabolites (<3% TRR).

Conclusions.  Adequate studies are available depicting the metabolism of
[14C]fenbuconazole in peaches, peanuts, sugar beets, and wheat.  The
qualitative nature of fenbuconazole residues in plants is adequately
understood for the purposes of the current tolerance petitions.  The
residues of concern in/on peppers, bushberries, and cranberries are
fenbuconazole, its lactone metabolites, RH-9129 and RH-9130, and the
triazole metabolites, 1,2,4-triazole, triazole alanine, and triazole
acetic acid.

860.1300 Nature of the Residue - Livestock

There are no livestock feedstuffs associated with the established or
proposed uses on peppers, bushberries, or cranberries; therefore, data
requirements for livestock metabolism are not relevant to this tolerance
petition

860.1340 Residue Analytical Methods

A GC/NPD tolerance enforcement method, 34-90-47R, is available for
determining residues of fenbuconazole, RH-9129, and RH-9130 in/on stone
fruits.  For this method, residues are extracted with methanol, filtered
through Celite, diluted with aqueous 9.1% NaCl, and partitioned into
methylene chloride.  Residues are then concentrated, redissolved in
toluene:acetone (100:10, v:v), and cleaned up using a silica gel column
eluted with toluene:acetone (100:30, v:v).  Residues in the resulting
eluate are concentrated to dryness, redissolved in toluene:acetone
(100:5, v/v), and eluted through a Florisil column with toluene:acetone
(100:30, v:v).  Residues are again concentrated to dryness, redissolved
in toluene:methanol (100:3, v:v), and analyzed by GC/NPD using external
standards.  The reported LOQ is 0.01 ppm each for fenbuconazole,
RH-9129, and RH-9130.

Residues in/on peppers were determined using a slightly modified version
of the above method. The modifications were made to improve the
performance of the method.  The GC/NPD method was adequately validated
prior to, and in conjunction with, the analysis of field trial samples
using control samples fortified with each analyte at 0.01-1.0 ppm.  The
validated LOQ for each analyte is 0.01 ppm in/on peppers, for a combined
LOQ of 0.03 ppm.

The above method was validated for analysis on blueberries and
cranberries in conjunction with the field trials.  For cranberry samples
fortified with each analyte separately at 0.01-2.0 ppm, average method
recoveries were 101% with a standard deviation (s.d.) of 10% for parent,
100% (s.d. 14%) for RH-9129, and 97% (s.d. 13%) for RH-9130.  For
blueberry samples fortified with each analyte separately at 0.01-1 ppm,
average method recoveries were 102% (s.d. 9%) for parent, 95% (s.d. 6%)
for RH-9129, and 96% (s.d. 4%) for RH-9130.

Conclusions.  The available GC/NPD method, TR 34-90-47R, is adequate for
enforcing tolerances and collecting data on fenbuconazole residues in/on
peppers, bushberries, and cranberries.

860.1360 Multiresidue Methods

Adequate multiresidue method testing data are available for
fenbuconazole and its lactone metabolites.  The FDA PESTDATA database,
dated 11/01 (PAM Vol. I, Appendix I), indicates that fenbuconazole is
completely recovered using Multiresidue Methods Section 302 (Protocol
D), but is not recovered by Methods 303 and 304 (Protocols E and F). 
The recovery of the lactone metabolites (RH-9129 and RH-9130) through
Method 302 was variable or partial (68-92% for RH-9129 and 48-71% for
RH-9130), and the recovery of RH-6467 was small (<50%).  None of these
metabolites were recovered through Methods 303 or 304.

860.1380 Storage Stability

Memo, D249012, W. Wassell, 11/19/98

Memo, D223761, W. Wassell. 4/23/96

Memo, D239002, G. Otakie, 3/30/06

Adequate storage stability data are available indicating that
fenbuconazole and its lactone metabolites (RH-9129 and RH-9130) are
stable in frozen storage for up to 54 months in pecans and stone fruits,
and 36 months in apples, wheat grain, and wheat straw.

(≤-10ºC) as the field trial samples.  No 0-day analysis was conducted
prior to placing the samples in frozen storage; therefore, the original
fortification levels could not be verified.  After 16.6 months of frozen
storage, the stored samples were analyzed in triplicate along with a
control sample and control samples freshly fortified with each analyte
at 1.0 ppm.  The average recovery (corrected for concurrent recovery)
was 89% for fenbuconazole and RH-9130 and 91% for RH-9129.  These data
indicate that fenbuconazole, RH-9129, and RH-9130 are stable in frozen
peppers for up to 16.6 months.  Samples from the pepper field trials
were stored at <-10°C for up to 16.4 months prior to analysis.

Studies examining the stability of fenbuconazole, RH-9129, and RH-9130
during frozen storage were conducted in conjunction with the blueberry
(44690601.der) and cranberry (45296001.der) field trials.  Triplicate
control samples of blueberry fruit were fortified separately with the
three analytes at ~1 ppm and placed in frozen storage (<-14(C) for 240
days, and triplicate control samples of cranberry fruit were fortified
separately with the three analytes at 2.02 ppm and placed in frozen
storage (<-10(C) for up to 168 days.  The stored samples were analyzed
along with freshly fortified control samples.  For blueberry, average
corrected recoveries of parent, RH-9129, and RH-9130 were 99%, 98%, and
100%, respectively, following 7.9 months of frozen storage.  For
cranberry, average corrected recoveries of parent, RH-9129, and RH-9130
were 91%, 81%, and 91%, respectively, following 5.5 months of frozen
storage.  In the field trials, the maximum frozen storage durations were
7.9 months for blueberries and 5.3 months for cranberries.

Conclusions.  In the pepper storage stability study, no 0-day analysis
was conducted on the fortified samples prior to storage.  However, for
the purposes of the pepper tolerance petition, HED accepts the available
data to support the pepper field trials.

The available storage stability data are adequate and support the sample
storage durations and conditions used in the blueberry and cranberry
field trials.

860.1400 Water, Fish, and Irrigated Crops

There are no proposed uses that are relevant to this guideline topic.

860.1460 Food Handling

There are no proposed uses that are relevant to this guideline topic.

860.1480 Meat, Milk, Poultry, and Eggs

As there are no livestock feedstuffs associated with the
proposed/established uses on peppers, blueberries, and cranberries, data
requirements pertaining to meat, milk, poultry, and eggs are not
relevant to these tolerance petitions.

860.1500 Crop Field Trials

47215801.der (peppers)

IR-4 submitted field trial data on bell and non-bell peppers to support
the proposed use of fenbuconazole (WP) on peppers.    SEQ CHAPTER \h \r
1 The results from these tests are discussed below, and the residue data
are summarized in Table 4.



Table 4.	Summary of Residue Data from Pepper Field Trials with
Fenbuconazole (WP).

Crop matrix	Total Applic. Rate  (lb ai/A)	PHI (days)	Combined Residue
Levels (ppm) 1



	n	Min.	Max.	HAFT 2	Median	Mean	Std. Dev.

Peppers (proposed use = 0.75 lb ai/A total application rate, 7-day PHI)

Bell and Non-bell Peppers	0.656-0.844	6-7	18	0.05	0.22	0.21	0.15	0.14
0.06

1	The calculated LOQs were 0.008 ppm for fenbuconazole, 0.010 ppm for
RH-9129 and 0.011 ppm for RH-9130.  The

	calculated LODs were 0.003 ppm for fenbuconazole and RH-9129, and 0.004
ppm for RH-9130.  The LLMV in/on peppers

	for each analyte is 0.01 ppm, for a combined LLMV of 0.03 ppm.

2	HAFT = Highest average field trial result.

Nine field trials were conducted on bell peppers (6 tests) and non-bell
peppers (3 tests) during 2000 in EPA Growing Zones 2, 3, 5, 6, and 10. 
At each test site, fenbuconazole (75% WP) was applied to peppers during
fruit development and maturation as four or five broadcast foliar
applications at rates of 0.163-0.173 lb ai/A (0.9x single rate), at RTIs
of 10-14 days, for totals of 0.66-0.68 or 0.84 lb ai/A (0.9-1.1x total
rate).  Three of the nine trials used a fifth application because
peppers in these tests were too immature for harvest following the
fourth application.  All applications were made using ground equipment
in volumes of 29-53 gal/A, and included the use of non-ionic surfactants
at 0.12-0.13% v/v.  Single control and duplicate treated samples of
peppers were harvested from each test site at 6-7 DAT.  Additional
samples from three field trials were collected at 0 and 14 DAT to
measure residue decline.  Samples were stored frozen for up to 493 days,
a duration supported by available storage stability data.

The GC/NPD method used to determine residues of fenbuconazole and
Metabolites RH-9129 and RH-9130 in/on peppers was adequately validated
prior to, and in conjunction with, the analysis of field trial samples. 
This method is a slightly modified version of the current tolerance
enforcement method for stone fruits.  The statistically calculated LOQs
were 0.008 ppm for fenbuconazole, 0.010 ppm for RH-9129 and 0.011 ppm
for RH-9130.  The calculated LODs were 0.003 ppm for fenbuconazole and
RH-9129, and 0.004 ppm for RH-9130.  The lower limit of method
validation (LLMV) in/on peppers for each analyte is 0.01 ppm, for a
combined LLMV of 0.03 ppm.

RH-9130 were ≤0.01 ppm in/on all pepper samples harvested at 6-7 DAT. 
The average combined fenbuconazole residue in/on peppers was 0.14 ppm
and the highest average field trial (HAFT) combined residues were 0.21
ppm.  In the three residue decline tests, average combined fenbuconazole
residues in/on peppers declined from 0.25-0.43 ppm at 0 DAT to 0.10-0.19
ppm by 14 DAT.

44690601.der (blueberry)

45268401.der (blueberry)

45296001.der (cranberry)

To support the use of fenbuconazole (75% WP) on cranberries and
bushberries, IR-4 submitted field trial data for cranberries and high
bush blueberries, respectively.  Blueberries are the representative crop
for Crop Subgroup 13-B.  The results from these field trials are
discussed below and summarized in Table 5.

Table 5.	Summary of Residue Data for Crop Field Trials using
Fenbuconazole (WP).



Commodity (MRIDs)	

Formulation	

Total Rate

(lb ai/A) 	

PHI (days)	

Combined Residues (ppm) 1







n	

Min.	

Max.	

HAFT 3	

Median (STMdR4)	

Mean (STMR4)	

Std. Dev.



Bushberries (proposed use = 0.47 lb ai/A total application rate, 30-day
PHI)



Blueberry 5

(44690601 & 45268401)	

75% WP	

0.47	

25-35	

18	

0.03	

0.24	

0.19	

0.080	

0.083	

0.048



Cranberry (proposed use = 0.94 lb ai/A total application rate, 30-day
PHI)



Cranberry

(45296001)	

75% WP	

0.918-0.944	

25-28	

10	

0.09	

0.49	

0.45	

0.160	

0.20	

0.13

1  The combined residues include parent and the lactone metabolites
RH-9129 and RH-9130, expressed in parent equivalents.  The LOQ is 0.01
ppm for each analyte in/on berries, for a combined LOQ of 0.03 ppm.  For
calculation of the median, mean, and standard deviation, ½LOQ was used
for samples with residues <LOQ.

3  HAFT = Highest Average Field Trial. 

4  STMdR = Supervised Trial Median Residue;  STMR = Supervised Trial
Mean Residue.

5  Includes data from the 9 acceptable blueberry field trials only.

Blueberry

Eight blueberry field trials were conducted during 1996 and 1997
(44690601.der) in EPA Growing Zones 1 (NH, 1 trial), 3 (NJ, NC, GA, 1
trial each), 5 (MI, 3 trials) and 12 (OR, 1 trial).  Except in the NJ
field trial, fenbuconazole (75% WP) was applied to high bush blueberries
as five broadcast foliar applications beginning at green tip and
continuing through fruit development at target rates of 0.094 lb
ai/A/application, for a total of 0.47 lb ai/A/season.  Actual
application rates were reported for the NJ test only, in which
fenbuconazole was applied below the target rate, for a total of 0.28 lb
ai/A (0.6x rate).  RTIs varied considerably, but were generally 7 to 21
days between the first 4 applications, and 28-39 days between the fourth
and fifth applications.  In each trial, applications were made using
ground equipment at 16-91 gal/A and included the use of a non-ionic
surfactant at an unspecified rate.  Duplicate control and treated
samples of berries were collected from each test at 25-35 DAT.  Samples
were stored frozen from collection to analysis for up to 7.9 months, a
duration supported by the available stability data.

Residues of fenbuconazole, RH-9129, and RH-9130 were determined using
the current GC/NPD tolerance enforcement method (Report No. 34-90-47R),
with minor modifications.  The method was adequately validated in
conjunction with the field trial analyses and has an LOQ of 0.01 ppm for
each analyte, for a combined LOQ of 0.03 ppm.  The LOD was not reported.

There is a question as to the adequacy of the three Michigan field
trials that were performed in 1996 and 1997.  The trials were conducted
with a hand-pumped sprayer.  It took about 50 seconds to spray the plot.
 The sprayer was pumped to 60 psi and then re-pumped to 60 psi after
every 15 seconds of spray time.  IR-4 personnel stated that they were
not certain that that procedure would maintain the appropriate spray
pressure, and the low pressures reached were not recorded.  Because of
the question concerning the adequacy of the Michigan field trials, IR-4
performed two additional trials in 1998.  HED considered these trials to
be adequate (Memo, D316607, M. Collantes, et al., 8/3/2006).  However,
HED felt that only six of the ten blueberry field trials that were
submitted were adequate.  Three were considered to be inadequate because
of the pump pressure issue, and the New Jersey trial was considered to
be inadequate because it was performed at a 0.6x application rate.  In
2006, HED recommended in favor of a conditional registration on
bushberries and requested that IR-4 perform two additional field trials.
 HED requested that these two trials be performed because eight were
needed for the Bushberry Subgroup and, as stated above, HED felt that
only six acceptable trials had been submitted.

IR-4 personnel responded by stating that they felt that the three
original Michigan field trials should be considered to be acceptable. 
They were of that opinion because the person who made the applications
in the field trials was an experienced applicator.  They stated that the
applicator probably observed the pressure drop during previous
applications and compensated for it by re-pumping every 15 seconds of
spray time.  He calibrated his apparatus in this manner.  They also
stated that the results of the Michigan field trials were consistent
with the results of the other four acceptable field trials.  The data
from 2 of the 3 trials fall within the ranges of the data from the other
trials.  Excluding the Michigan trials, the combined residues of parent
and metabolites range from 0.05 ppm to 0.24 ppm.  In 2 of the Michigan
trials the residues range from 0.05 to 0.09 ppm.  In the 3rd trial, the
combined residues are 0.03 ppm for both samples.  In that case, the
parent and isomers were all detected at the LOQ of 0.01 ppm.

In the eight field trials, residues of fenbuconazole ranged from <0.01
ppm to 0.20 ppm.  Residues of RH-9129 ranged from <0.01ppm to 0.03 ppm,
and residues of RH-9130 were either at, or below, the LOQ of 0.01 ppm. 
Combined residues, expressed as parent equivalents, ranged from 0.03 ppm
to 0.24 ppm.

In the 2 additional blueberry field trials conducted during 1998 in
Michigan (45268401.der), fenbuconazole (75% WP) was applied to high bush
blueberries as five broadcast foliar applications beginning at green tip
and continuing through fruit development at 0.094-0.096 lb
ai/A/application, for a total of 0.47 lb ai/A/season.  RTIs were 7-17
days between the first 4 applications, and 54-64 days between the fourth
and fifth applications.  Applications were made using ground equipment
at ~50 gal/A and included the use of a non-ionic surfactant at ~0.1% of
the spray mix.  Duplicate control and treated samples of berries were
collected from each test at 30 DAT.  Samples were stored frozen from
collection to analysis for up to 5.2 months, a duration supported by the
available stability data.

Residues of fenbuconazole, RH-9129, and RH-9130 were determined using
the current GC/NPD tolerance enforcement method (Report No. 34-90-47R),
with minor modifications.  The method was adequately validated in
conjunction with the field trial analyses and has an LOQ of 0.01 ppm for
each analyte, for a combined LOQ of 0.03 ppm.  The LOD was not reported.

Residues of fenbuconazole were 0.06-0.07 ppm in/on the 4 blueberry
samples from the two additional trials, and residues of both RH-9129 and
RH-9130 were at or below the LOQ of 0.01 ppm in all samples.  Combined
residues (expressed in parent equivalents) were 0.08 to 0.09 ppm.

Considering both sets of blueberry field trials together, nine field
trials are available reflecting the 1x application.  The combined
residues of fenbuconazole, RH-9129, and RH-9130 (expressed as parent)
were 0.03-0.24 ppm in/on 18 samples harvested 25-35 DAT.  Average
combined residues are 0.083 ppm (with a standard deviation of 0.048 ppm)
and combined HAFT residues are 0.19 ppm.  Apparent residues of each
analyte are <LOQ in/on all 18 control samples.

The geographical representation of field trials is not completely in
accordance with that which is recommended in the OPPTS Series 860
Guidelines.  Three trials in Zone 2 are recommended, but only two
acceptable trials were submitted.  The New Jersey trial was performed in
Zone 2, but it is not acceptable.  However, 5 acceptable trials were
performed in Zone 5 whereas only 3 are recommended.

Cranberry

In five field trials conducted during 1998, fenbuconazole (75% WP) was
applied to cranberries as five broadcast foliar applications at
0.178-0.194 lb ai/A/application, for a total of 0.918-0.944 lb
ai/A/season.  Applications began at flowering and continued through
fruit development at RTIs of 10-14 days.  Applications were made using
ground equipment at 30-300 gal/A and included the use of a non-ionic
surfactant at ~0.1% of the spray volume.  Duplicate control and treated
samples of cranberries were harvested from each test at 25-28 DAT. 
Samples were stored frozen from collection to analysis for up to 5.3
months, a duration supported by the available storage stability data.

Residues of fenbuconazole, RH-9129, and RH-9130 were determined using
the GC/NPD tolerance enforcement method (Report No. 34-90-47R), with
minor modifications.  The method was adequately validated in conjunction
with the field trial analyses and has an LOQ of 0.01 ppm for each
analyte, for a combined LOQ of 0.03 ppm.  The LOD was not reported.

At 25-28 days after the final application, residues of fenbuconazole
were 0.07-0.45 ppm in/on 10 treated cranberry samples.  Residues of
RH-9129 were 0.01-0.04 ppm and residues of RH-9130 were <0.01-0.01 ppm,
for total combined residues of 0.09-0.49 ppm (expressed in parent
equivalents).  Average combined residues were 0.20 ppm and combined HAFT
residues were 0.45 ppm.  Apparent residues of each analyte were <LOQ
in/on all 10 control samples.

Conclusions.  Although the single application rates for peppers were
slightly below (0.9x) the maximum proposed use rate, the submitted field
trial data are adequate and support the use of fenbuconazole (WP) on
peppers.  Adequate numbers of tests were conducted in the appropriate
geographical regions, and samples were analyzed for residues of concern
using an adequate data collection method.

HED concludes that nine of the ten submitted blueberry field trials are
adequate.  The trial performed in New Jersey is not adequate because the
application rate is only 0.6x the label rate.  HED feels that the three
original Michigan field trials are acceptable.  Although there is a
question as to the application technique, the results of the trials in
question are consistent with the results of the other trials.  In one of
these trials, residues were below the range of residue values in the
other trials; however, they were not significantly below.  When the
recommended tolerance is determined using HED’s statistical tolerance
generator, the same tolerance is generated regardless of whether or not
this sample is included.  The recommended tolerance is 0.25 ppm.  In
addition, the field report states that application instrumentation was
calibrated at each application.

In the nine acceptable field trials, fruit samples were collected at the
appropriate intervals, and were analyzed using an adequate method.  The
sample storage durations are also supported by the available storage
stability data.  Data from these nine blueberry field trials support the
use of up to five foliar applications of fenbuconazole (WP or FlC) to
bushberries at up to 0.094 lb ai/A/application, for a maximum seasonal
rate of 0.47 lb ai/A.  The data support the established PHI of 30 days,
a minimum RTI of 10 days, and the use of a non-ionic surfactant in the
spray mix.

For cranberries, adequate numbers of tests were conducted in
representative geographic regions, and the fruit samples were collected
at intervals slightly shorter than the proposed PHI.  Samples were
analyzed using an adequate method, and the sample storage durations are
supported by the available storage stability data.  The available
cranberry data are adequate and support the use of up to five foliar
applications of fenbuconazole (WP or FlC) at up to 0.188 lb
ai/A/application, for a maximum seasonal rate of 0.94 lb ai/A.  The data
support the proposed PHI of 30 days, a minimum RTI of 10 days, and the
use of a non-ionic surfactant in the spray mix.  As maximum combined
residues were 0.49 ppm at 25-28 DAT, a tolerance of 0.5 ppm will be
sufficient to cover the 30-day PHI.  In the pepper, blueberry, and
cranberry field trials, no residue data were provided on 1,2,4-triazole,
TA, or TAA as required under the current guidance for field trials using
triazole compounds (Memo, D327788, M. Doherty, 4/25/2006).

860.1520 Processed Food and Feed

HED does not require residue data for any processed commodities
associated with peppers, blueberries, or cranberries.  Therefore, data
requirements for processed food and feed are not relevant to these
tolerance petitions.

  SEQ CHAPTER \h \r 1 860.1650 Submittal of Analytical Reference
Standards

Analytical reference standards for fenbuconazole and its metabolites,
RH-9129 and RH-9130, are available at the EPA National Standards
Repository (Electronic communication, D. Wright, 4/21/2008).  Their
expiration dates are as follows:  fenbuconazole (3/21/2009), RH-9129
(1/4/2009), and RH-9130 (8/17/2009).

860.1850/1900 Confined and Field Accumulation in Rotational Crops

D259204, S. Oonnithan, 7/25/06

An adequate confined rotational crop study is available indicating that
the metabolite profile for fenbuconazole in rotational crops is similar
to the metabolism in primary crops.  Limited rotational crop field
trials and rotational crop tolerances are not required provided that the
labels specify a minimum PBI of 35 days following applications to
peppers totaling ≤0.188 lb ai/A and a minimum PBI of 210 days
following applications totaling 1.0 lb ai/A.

As bushberries and cranberries are perennial crops, requirements
pertaining to rotational crops are not relevant to these petitions.

860.1550 Proposed Tolerances

For purposes of establishing tolerances, HED has concluded that the
residues of concern in plants include fenbuconazole and its lactone
metabolites, RH-9129 and RH-9130.  A permanent tolerance is established
for the combined residues of fenbuconazole and Metabolites RH-9129 and
RH-9130, expressed as parent equivalents on cranberries at 0.5 ppm.  A
tolerance is established for the Bushberry Subgroup, Crop Subgroup 13-B,
at 0.3 ppm.

Using the Agency’s Guidelines for Setting Pesticide Tolerances Based
on Field Trial Data, the appropriate tolerance for pepper was calculated
using the 6-7 DAT residue data from the adequate U.S. field trials
conducted at a 0.9x rate.  The calculated tolerance for peppers was 0.40
ppm (Appendix II).  The tolerances that are generated for cranberries
and blueberries are 0.70 ppm and 0.25 ppm, respectively. 

Maximum residue limits (MRLs) for residues of fenbuconazole have been
established by Codex, Canada, and Mexico.  The residue definition for
both Codex and Mexico is fenbuconazole, per se, and the Canadian residue
definition is the combined residues of fenbuconazole and its
metabolites, RH-9129 and RH-9130, each expressed as parent (i.e., the
same as the U.S. tolerance definition).  As there are no established or
proposed Canadian, Mexican, or Codex MRLs for fenbuconazole on peppers,
there are no international harmonization issues for the pepper tolerance
petition.

The U.S. has already established tolerances for cranberries at 0.5 ppm
and bushberries at 0.3 ppm.  Mexico established tolerances for these
commodities based on the established U.S. tolerances.  Therefore, HED
recommends that the current tolerances remain in effect, even though
they are different than the tolerances that are recommended by HED’s
statistical tolerance generator.  As a result, HED recommends that the
0.30 ppm tolerance for bushberries remain in effect, even though the
tolerance generator recommends a tolerance of 0.25 ppm, and the 0.50 ppm
tolerance for cranberries remain in effect, even though the tolerance
generator recommends a tolerance of 0.70 ppm.



Table 6. 	Tolerance Summary for Fenbuconazole.

Commodity	Proposed Tolerance (ppm)	Recommended Tolerance (ppm)	Comments;

Correct Commodity Definition

Pepper	0.4	0.40	Adequate field trial data are available on peppers.

Commodity definition:  Pepper 



References

Fenbuconazole on Stone Fruit, Pecans, Almonds, Bananas, Apples, and
Wheat.  New Chemical Registration.  Issues to be Presented at the
12/15/93 Meeting of the HED Metabolism Committee., N. Dodd and W.
Wassell, 12/10/93

Fenbuconazole Metabolism in Stone Fruit, Pecans, Almonds, Bananas,
Apples, and Wheat.  The HED Metabolism Committee Meeting Held on
3/1/94., N. Dodd and W. Wassell, 3/9/94.

D200171, PP#1F3995.  Fenbuconazole on Pecans.  Amendment dated 2/25/94,
N. Dodd, 4/5/1994.

D197760, PP# 1F3989 - Fenbuconazole on Stone Fruit.  Revised Enforcement
Method, N. Dodd, 4/8/94, MRID:  43044401.

D223758, PP#2F4127.  Fenbuconazole, Govern 2F and Govern 75WSP
Agricultural Fungicide in or on Wheat.  Amendment of 2/1/96, W. Wassell,
4/23/96.

D249012, Fenbuconazole (RH-7592 Technical, Enable 2F and Indar 75WSP,
respectively) in/on the Crop Group Stone Fruit (except plums and prunes)
and the Crops Bananas and Pecans.  Evaluation of Crop Field Trial Data
and Storage Stability Data, W. Wassell, 11/19/98.

D241864, Fenbuconazole. Request for Tolerances on Sugar Beets. Summary
of Analytical Chemistry and Residue Data. Petition Number: 7F4887, G.
Otakie, 3/30/06.

D239002, Fenbuconazole. Request for Tolerances on Apples. Summary of
Analytical Chemistry and Residue Data. Petition Number 2F4135, G.
Otakie, 3/30/06.

327788, Triazole-Based Metabolites:  Guidance On Residue Chemistry Data
Submissions, M. Doherty, 4/25/2006.

D259204, Fenbuconazole. Request for Tolerances on Peanuts. Summary of
Analytical Chemistry and Residue Data, S. Oonnithan, 7/25/06.

Multiresidue Test Information for Updating PAM I, N. Dodd, 1/27/93,
MRID:  41875044.

	

  SEQ CHAPTER \h \r 1 Attachments:

 

Appendix I – International Residue Limit Status sheet 

 α-[2-(4-chlorophenyl)ethyl]-α-phenyl-1H-1,2,4-triazole-1-propanenitri
le	Common Name: Fenbuconazole

	X Proposed tolerance

⁪ Reevaluated tolerance

⁪ Other	Date:  1/22/2008

Codex Status (Maximum Residue Limits)	U. S. Tolerances

⁪ No Codex proposal step 6 or above

X No Codex proposal step 6 or above for the crops requested	Petition
Numbers: 7F7256

DP Number:  	345256

Other Identifier:  

Residue definition (step 8/CXL): Fenbuconazole	Reviewer/Branch:  C.
Swartz/RAB2

	Residue definition:  Combined residues of fenbuconazole and its lactone
metabolites, RH-9129 and RH-9130, each expressed as fenbuconazole.

Crop (s)	MRL (mg/kg)	Crop(s) 	Tolerance (ppm)



Peppers	0.40



Bushberry Subgroup	0.3



Cranberry	0.5



































	Limits for Canada	Limits for Mexico

⁪ No Limits

X No Limits for the crops requested	⁪ No Limits

⁪ No Limits for the crops requested

Residue definition: Combined residues of fenbuconazole and its lactone
metabolites, RH-9129 and RH-9130, each expressed as fenbuconazole.
Residue definition:  Fenbuconazole

Crop(s)	MRL (mg/kg)	Crop(s)	MRL (mg/kg)



Blueberries	0.3 ppm (US tolerance)



Cranberries	0.5 ppm (US tolerance)

Notes/Special Instructions:



	

Appendix II - Tolerance Assessment Calculations and Field Trial
Results.

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--day PHI.  As specified by the Guidance for Setting Pesticide
Tolerances Based on Field Trial Data SOP, the field trial application
rates and PHIs are within 25% of the maximum label application rate and
minimum label PHI, respectively.  The residue values used to calculate
the tolerance are provided in Table II-1.  The combined residues of
fenbuconazole and its metabolites were above the LOQ (0.03 ppm) in all
field trial samples.

The dataset was entered into the tolerance spreadsheet.  Visual
inspection of the lognormal probability plot (Figure II-1) provided in
the spreadsheet indicates that the dataset is reasonably lognormal.  The
result from the approximate Shapiro-Francia test statistic (Figure II-2)
confirmed that the assumption of lognormality should not be rejected. 
Because the field trial data for the combined residues represent a large
dataset (>15 samples) and are reasonably lognormal, the 99th percentile
was selected as the appropriate percentile for the pepper tolerance
level (0.40 ppm). 

Table II-1.	Residue data used to calculate tolerance for fenbuconazole
on peppers.

Regulator:	EPA

Chemical:	Fenbuconazole

Crop:	Bell and Non-Bell Peppers

PHI:	6-7 days

App. Rate:	0.66-0.84 lb ai/A/season

Submitter:	IR-4

MRID Citation:	MRID 47215801

	Combined Residues

	0.05	0.16

	0.06	0.16

	0.07	0.17

	0.07	0.17

	0.07	0.18

	0.07	0.19

	0.10	0.22

	0.12	0.22

	0.14	0.22





Figure II-1.	Lognormal probability plot of fenbuconazole field trial
data for peppers

Figure II-2.	Tolerance spreadsheet summary of fenbuconazole field trial
data for peppers.



Table II-2.                                              	Blueberry
Field Trial Data

Chemical:	Fenbuconazole

Crop:	Blueberries

PHI:	25-35  days

App. Rate:	0.47 lb ai/A/season

Submitter:	IR-4

MRID Citation:	MRIDs 44690601 and 45268401

	Combined Residues (ppm)

	0.03	0.08

	0.03	0.08

	0.05	0.08

	0.05	0.09

	0.05	0.09

	0.05	0.10

	0.07	0.12

	0.08	0.13

	0.08	0.24



Table II-3.	                                                 Cranberry
Field Trial Data

Chemical:	Fenbuconazole

Crop:	Cranberries

PHI:	25-28 days

App. Rate:	0.92-0.94 lb ai/A/season

Submitter:	IR-4

MRID Citation:	MRID 45296001

	Combined Residues (ppm)

	0.09	0.17

	0.10	0.17

	0.11	0.20

	0.12	0.41

	0.16	0.47



 PAGE   

Page   PAGE  1  of   NUMPAGES  24 

Fenbuconazole	Summary of Analytical Chemistry and Residue Data	DP#: 
313752

