UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

WASHINGTON, D.C.  20460

OFFICE OF           

PREVENTION, PESTICIDES

AND TOXIC SUBSTANCES

MEMORANDUM

Date:		14-SEP-2006

Subject:		Diflubenzuron.  IR-4’s Request To Register New Food/Feed
Uses on Barley, Oats, Wheat, Brassica Leafy Greens (Crop Subgroup 5B),
Turnip Greens, Eggplant, Okra, Peanut, and Pummelo.  Summary of
Analytical Chemistry and Residue Data.  PP#s 5E6965, 5E6966, and 5E6967.

DP#s:	321623, 321625, and 321627	Decision #s:	359314, 359335, and 359336

PC Code:	108201	MRID #s.:	46609401, 46609501, and 46609601



40 CFR §180.	377



Chemical Family:	Urea Derivative





From:		George F. Kramer, Ph.D., Senior Chemist

		Registration Action Branch (RAB1)

		Health Effects Division (HED) (7509P)

Through:		P.V. Shah, Ph.D., Branch Senior Scientist

		RAB1/HED (7509P)

To:		Barbara Madden/Dan Rosenblatt, PM Team 05

		Registration Division (RD; 7505P)

This document was originally prepared under contract by Dynamac
Corporation (2275 Research Blvd, Suite 300; Rockville, MD 20850;
submitted 06/23/2006).  The document has been reviewed by HED and
revised to reflect current Office of Pesticide Programs (OPP) policies.

Executive Summary

Diflubenzuron
(N-[((4-chlorophenyl)amino)carbonyl]-2,6-difluorobenzimide), a member of
the urea-derivative chemical family, is an insecticide/acaricide (insect
growth regulator) that behaves as a chitin inhibitor to suppress the
growth of many leaf-eating larvae, mosquito larvae, aquatic midges, rust
mite, boll weevil, and flies.  The Interregional Research Project No. 4
(IR-4), in cooperation with Crompton Corporation, has submitted several
petitions for the establishment of permanent diflubenzuron tolerances on
several raw agricultural and processed commodities.

Under PP#5E6965, IR-4 requests the establishment of tolerances for the
combined residues of diflubenzuron and its metabolites
4-chlorophenylurea (CPU) and 4-chloroaniline (PCA) in/on the following
raw agricultural commodities (RACs):

Barley, grain	0.06 ppm

Oat, grain	0.06 ppm

Wheat, grain	0.06 ppm

Barley, forage	5.0 ppm

Oat, forage	5.0 ppm

Wheat, forage	5.0 ppm

Barley, hay	2.0 ppm

Oat, hay	2.0 ppm

Wheat, hay	2.0 ppm

Barley, straw	2.0 ppm

Oat, straw	2.0 ppm

Wheat, straw	2.0 ppm

Grain, aspirated fractions	3.0 ppm

Pummelo	0.5 ppm

Under PP#5E6966, IR-4 requests the establishment of tolerances for the
combined residues of diflubenzuron and its metabolites CPU and PCA,
expressed as parent diflubenzuron, in/on the following RACs:

Brassica, leafy greens, subgroup 5B	8.0 ppm

Turnip greens	8.0 ppm

Eggplant	1.0 ppm

Okra	1.0 ppm

Lastly, under PP#5E6967, IR-4 requests the establishment of tolerances
for the combined residues of diflubenzuron and its metabolites CPU and
PCA, expressed as parent diflubenzuron, in/on the following raw
agricultural and processed commodities:

Peanut	0.2 ppm

Peanut, hay	20.0 ppm

Peanut, refined oil	0.2 ppm

The data package for the current petitions includes magnitude of the
residue studies on barley, wheat, peanuts, and mustard greens as well as
processing studies on peanuts and wheat.  These studies have been
reviewed by HED, and the Executive Summaries from the individual Data
Evaluation Records (DERs) are incorporated in this summary document.  No
residue data were submitted for some commodities, and the petitioner
requests translation of the available/submitted data:  (i) from barley
and wheat to oats; (ii) from grapefruit, orange (sweet), and tangerine
to pummelo; and (iii) from peppers to eggplant and okra.

IR-4 proposes to add new food/feed uses on the following diflubenzuron
end-use products:  Dimilin® 2L (EPA Reg. No. 400-461, a flowable
concentrate formulation containing 2 lb ai/gal), Dimilin® 25W (EPA Reg.
No. 400-465, a wettable powder formulation containing 25% ai), and
Micromite® 80WGS (EPA Reg. No. 400-487, 80%, a water-dispersible
granule formulation containing 80% ai.

Dimilin® 2L is proposed for use on:  (i) barley, oats, triticale, and
wheat for a maximum of one foliar application per growing season at
0.0625 lb ai/A with a preharvest interval (PHI) of 45 days for grain and
straw; (ii) Brassica leafy greens and turnip greens for up to 4 foliar
applications at 0.0625 lb ai/A/application for a seasonal rate of 0.25
lb ai/A with a 7-day PHI; and (iii) peanuts for up to 3 foliar
applications at 0.125 lb ai/A/application for a seasonal rate of 0.375
lb ai/A with a 28-day PHI.  Dimilin® 25W is proposed for use on
eggplant and okra for multiple foliar applications at a maximum single
application rate of 0.125 lb ai/A/application and a maximum seasonal
rate of 0.375 lb ai/A with a 7-day PHI.  Micromite® 80WGS is proposed
for use on pummelos for up to 3 foliar applications at 0.3125 lb
ai/A/application for a seasonal rate of 0.9375 lb ai/A with a 21-day
PHI.  Ground and/or aerial applications may be used for the above crops
except on Brassica leafy greens, turnips greens, eggplant, and okra
where applications may only be made by ground equipment.  The proposed
use of Dimilin® 2L on barley, oats, triticale, and wheat also specifies
that the formulation may also be applied by ultra-low-volume (ULV)
equipment.

Tolerances for residues of diflubenzuron are established under 40 CFR
§180.377.  Tolerances listed in 40 CFR §180.377(a)(1) are expressed in
terms of diflubenzuron per se.  Under this section, the listed
tolerances are:  (i) 0.05 ppm for residues in/on eggs, milk, and the fat
and meat of cattle, goat, hog, horse, poultry, and sheep, and for the
meat byproducts of poultry; (ii) 0.2 ppm for residues in/on undelinted
cottonseed and mushroom; (iii) 0.5 ppm for residues in/on grapefruit,
orange (sweet), tangerine, and soybean hulls; and (iv) 6.0 ppm for
residues in/on globe artichoke.

Tolerances listed in 40 CFR §180.377(a)(2) are expressed in terms of
the combined residues of diflubenzuron and its metabolites CPU and PCA. 
Under this section, the listed tolerances are:  (i) 0.02 ppm for
residues in/on rice grain; (ii) 0.06 ppm for residues in/on tree nuts
(group 14) and pistachios; (iii) 0.07 ppm for residues in/on fruit,
stone (group 12) except cherry; (iv) 0.15 ppm for residues in/on the
meat byproducts of cattle, goat, hog, horse, and sheep; (v) 0.50 ppm for
residues in/on pear; (vi) 0.8 ppm for residues in/on rice straw; (vii)
1.0 ppm for residues in/on pepper; and (viii) 6.0 ppm for residues in/on
almond hulls.

Time-limited tolerances listed in 40 CFR §180.377(b) are expressed in
terms of the combined residues of diflubenzuron and its metabolites CPU
and PCA, expressed as the parent diflubenzuron, in connection with use
of the pesticide under Section 18 Emergency Exemptions granted by EPA. 
Under this section, the listed tolerances are:  (i) 0.05 ppm for
residues in/on barley grain and wheat grain; (ii) 0.10 ppm for residues
in/on wheat milled byproducts; (iii) 0.50 ppm for residues in/on barley
straw and wheat straw; (iv) 1.0 ppm for residues in/on barley hay and
wheat hay; (v) 6.0 ppm for residues in/on alfalfa forage and alfalfa
hay; and (vi) 30 ppm for residues in/on wheat aspirated grain fractions.
 Tolerances for alfalfa commodities will expire 6/30/2007 and tolerances
for barley and wheat commodities will expire 12/31/08.

The qualitative nature of the residue in plants and fungi is adequately
understood based on data from citrus, mushroom, rice, and soybean
metabolism studies.  The metabolism of diflubenzuron in crops tested is
similar, and the radioactive components are also similar to those found
in soil.  The nature of the residue in livestock is also adequately
understood based on acceptable poultry and ruminant metabolism studies
reflecting oral dosing.  The HED Metabolism Assessment Review Committee
(MARC) has concluded that the residues of concern in plants, livestock,
and fungi, for the purpose of tolerance expression, are diflubenzuron
and its metabolites PCA and CPU.

  SEQ CHAPTER \h \r 1 The nature of the residue in rotational crops is
adequately understood for purposes of reregistration (Residue Chemistry
Chapters for the Reregistration Eligibility Decision (RED) document,
3/15/95).  The Residue Chapter concluded that although the available
confined rotational crop study was inadequate to fully satisfy
reregistration requirements, another confined rotational crop study will
not be requested because the study allowed HED to make regulatory
conclusions regarding the need for limited rotational-crop studies and
to comment on the appropriateness of the currently established plantback
interval (PBI) on diflubenzuron end-use product labels.

An acceptable limited field rotational crop study has been submitted. 
HED’s review of the study concluded that   SEQ CHAPTER \h \r 1
quantifiable residues of diflubenzuron, CPU and PCA are unlikely to
occur in rotated crops planted at least 30 days following treatment at
the proposed rate.  The petitioner’s proposed PBI of 30 days is
appropriate.

There are adequate enforcement methods, published in the Pesticide
Analytical Manual (PAM, Vol. II), for determining diflubenzuron residues
of concern.  In addition, a new analytical methodology for plant
commodities was successfully validated by an independent laboratory as
well as by Agency chemists at the Analytical Chemistry Branch
(ACB)/Biological and Economics Analysis Division (BEAD) in conjunction
with the approved rice petition (PP#8F4925).  The new methods were
forwarded to the Food and Drug Administration (FDA) for publication in
PAM Vol. II as Roman Numeral Methods.  T  SEQ CHAPTER \h \r 1 hese
methods can separately determine residues of diflubenzuron by gas
chromatography/electron-capture detection (GC/ECD), CPU by GC/ECD, and
PCA by GC/mass spectrometry (MS).  The reported limit of quantitation
(LOQ) for diflubenzuron in/on rice grain, straw, and bran is 0.01 ppm,
and is 0.05 ppm in/on rice hull.  In rice straw, the LOQ for CPU is 0.01
ppm and 0.005 ppm for PCA.

Samples of raw agricultural and processed commodities, collected from
the field, processing, and storage stability studies, were separately
analyzed for residues of diflubenzuron, CPU, and PCA using methods,
which are similar or based on method submissions previously deemed
acceptable by HED.  The data-collection methods were adequately
validated, and method recoveries were generally within the acceptable
range of 70-120%.

The submitted storage stability data indicate that diflubenzuron is
reasonably stable in/on the RACs of barley, wheat, peanut, and mustard
greens as well as in the processed commodities of peanut.  However, CPU
exhibited instability in a few commodities and PCA exhibited instability
in many commodities.  The storage stability studies suggest that
residues of CPU and PCA should be corrected in order to determine the
residue levels that were present at the time of sample collection. 
However, HED has determined that correction of CPU and PCA residues for
degradation during storage would not have a significant effect on the
results of the submitted field trials because individual residues of the
metabolites in/on treated RAC samples were mostly below the respective
LOQs.

Additional storage stability data for wheat processed commodities
(except bran) are requested to validate the storage conditions and
intervals of samples from the submitted wheat processing study.

There are ruminant and/or poultry feed items associated with the
proposed uses of diflubenzuron on barley, oats, wheat, and peanuts.  The
calculated maximum theoretical dietary burdens (22.2 ppm for beef
cattle, 34.8 ppm for dairy cattle, 0.052 ppm for poultry, and 0.058 ppm
for hog), resulting from the proposed/registered uses, are supported by
previously submitted livestock feeding studies.  HED concludes that the
current tolerances on meat, milk, poultry, and eggs are adequate to
cover the added residues resulting from the proposed uses.

Adequate magnitude of the residue data have been submitted for barley
grain, barley hay, barley straw, wheat grain, wheat forage, wheat hay,
and wheat straw.  These data were generated from field trials using
spray volumes of 10-20 gallons per acre using ground equipment.  The
petitioner should delete the proposed application method using ULV
(24-32 fl. oz/A) equipment. Barley forage is not listed in Table 1 of
OPPTS 860.1000 and should be removed from the petitioner’s Section F. 
As the proposed use is geographically limited, the available data for
wheat may be translated to oats; the corresponding tolerances
recommended for wheat commodities also apply to oat commodities.  The
proposed use on triticale is supported by the submitted data for wheat
as per 40 CFR 180.1.

The established grapefruit tolerance may be used to support the
requested tolerance of 0.5 ppm on pummelos.

Adequate magnitude of the residue data have been submitted for mustard
greens, the representative commodity of the Brassica leafy greens
(subgroup 5B).

Turnip greens will be removed from Crop Group 2:  Leaves of root and
tuber vegetables group, and will become a member of Crop Subgroup 5B: 
Leafy Brassica greens (Reviewer’s Guide and Summary..., B. Schneider,
6/14/02).  Forage turnip varieties grown for livestock feed uses only
will remain in Crop Group 2:  Leaves of root and tuber vegetables group.
 As mustard greens are the representative commodity of the Brassica
leafy greens (subgroup 5B), the mustard green residue data can be
translated to turnip greens.  However, the label should be amended to
prohibit use on dual purpose turnip cultivars or varieties which produce
a harvestable root.

No residue data were submitted in support of the proposed uses on okra
or eggplant.  The petitioner requests translation of the available data
from pepper to okra and eggplant.  However, HED does not generally
translate residue data among members of a crop group unless a crop group
tolerance is established.  Thus, the proposed tolerances for okra and
eggplant should be withdrawn and the use directions for okra and
eggplant removed from the label until adequate okra and eggplant residue
data are available or a crop group tolerance for fruiting vegetables is
established.

The submitted data for peanut nutmeat and peanut hay are inadequate
because geographic representation of residue data is insufficient as the
results from three trials were invalidated because of possible sample
contamination.  Confirmatory residue data from an additional three
peanut field trials conducted in Zone 2 are requested.

The submitted peanut processing study is inadequate because the study
has not definitively proven that diflubenzuron residues of concern will
not concentrate in the processed commodities of peanuts as a result of
the proposed use.  A new peanut processing study is requested.

The submitted wheat processing study is not supported by adequate
storage stability data, and these data are requested.  Although
inadequate, the study indicates that the combined residues of
diflubenzuron and its CPU and PCA metabolites do not appear to
concentrate in shorts, middlings, flour, bran, and germ processed from
wheat grain treated at 1x and 10x the field rate.  The combined
residues, however, concentrated >35x and 180x in aspirated grain
fractions processed from wheat grain treated at 1x and 10x,
respectively.

  SEQ CHAPTER \h \r 1 REGULATORY RECOMMENDATIONS 

PP#5E6965:  Provided revised Sections B and F are submitted,   SEQ
CHAPTER \h \r 1 HED concludes there are no residue chemistry data
requirements that would preclude the establishment of the
HED-recommended tolerances for diflubenzuron in/on the relevant
commodities as specified in Table 12.  The proposed uses of Dimilin® 2L
on barley, oats, triticale, and wheat should be made conditional upon
resolving the storage stability deficiencies cited below.  The proposed
use of Micromite® 80WGS on pummelos can be unconditional.

PP#5E6966:  Provided revised Sections B and F are submitted,   SEQ
CHAPTER \h \r 1 HED concludes there are no residue chemistry data
requirements that would preclude the establishment of the
HED-recommended tolerances as specified in Table 12 and unconditional
registration for diflubenzuron on Brassica leafy greens (subgroup 5B)
and turnip greens.  

PP#5E6967:  Provided a revised Section F is submitted,   SEQ CHAPTER \h
\r 1 HED concludes there are no residue chemistry data requirements that
would preclude the establishment of the HED-recommended tolerances for
diflubenzuron in/on the relevant commodities as specified in Table 12. 
The proposed use of Dimilin® 2L on peanuts should be made conditional
upon submission of additional field trial and processing data as cited
below.  

RESIDUE CHEMISTRY DEFICIENCIES

860.1200 Directions for Use

Barley, oats, and wheat:  The petitioner should delete the proposed
application method using ULV (24-32 fl. oz/A) equipment.  Label
revisions are requested to specify appropriate PHIs based on the
reviewed data.  Labels should be revised to specify PHIs of 50 days for
grain and straw, 3 days for forage, and 15 days for hay.  

Turnip greens:  The label should be amended to prohibit use on dual
purpose turnip cultivars or varieties which produce a harvestable root.

Okra and eggplant:  The use directions for okra and eggplant should be
removed from the label.

860.1380 Storage Stability

Barley, oats, and wheat:  Additional storage stability data for wheat
processed commodities (except bran) are requested to validate the
storage conditions and intervals of samples from the submitted wheat
processing study.  The available storage stability data for rice bran
may be translated to wheat bran; the petitioner is only requested to
generate storage stability data for wheat flour, middlings, shorts, and
germ.  The requested data should reflect the storage conditions and
intervals of samples from the wheat processing study.

860.1500 Crop Field Trials

Peanut:  Confirmatory residue data on peanut nutmeat and peanut hay are
requested from three additional field trials conducted in Zone 2.

860.1520 Processed Food/Feed

Peanut:  A new peanut processing study is requested using a minimum
seasonal rate of ≥3x, which is the maximum theoretical concentration
factor (by crop) for peanuts.  The meal samples from this study should
be analyzed with a method which has a LOQ for diflubenzuron which is
comparable to that of the RAC (0.05 ppm).

860.1550 Proposed Tolerances

Barley, oats, and wheat:  A revised Section F should be submitted to
reflect HED-recommended tolerance levels of 3.0 ppm for residues in/on
barley hay, 1.8 ppm for residues in/on barley straw, 7.0 ppm for
residues in/on wheat forage, 6.0 ppm for residues in/on wheat hay, 3.5
ppm for residues in/on wheat straw, and 11 ppm for residues in/on
aspirated grain fractions.  Barley forage is not listed in Table 1 of
OPPTS 860.1000; therefore, this entry should be removed from the
petitioner’s Section F.  The available data for wheat may be
translated to oats; the corresponding tolerances recommended for wheat
commodities also apply to oat commodities.

Brassica leafy greens:  A revised Section F should be submitted to
reflect HED-recommended tolerance level of 9.0 ppm for residues in/on
Brassica leafy greens, subgroup 5B.

Peanut:  A revised Section F should be submitted to reflect
HED-recommended tolerance levels of 0.10 ppm for residues in/on peanut,
55 ppm for residues in/on peanut hay, and 0.20 ppm for residues in/on
peanut oil.

Mustard greens:  A revised Section F should be submitted to reflect
HED-recommended tolerance level of 9.0 ppm.

Okra and eggplant:  The proposed tolerances for okra and eggplant should
be withdrawn.

A human-health risk assessment will be prepared as a separate document.

Background

Diflubenzuron was first registered in the United States in 1979 for use
as an insecticide.  The Agency issued a Registration Standard for
diflubenzuron in September, 1985, (NTIS #PB86-176500).  Diflubenzuron
was also the subject of a Residue Chemistry Chapter dated 11/16/84, an
Addendum to the Registration Standard dated 12/4/84, and a
Reregistration Standard Update dated 6/21/91.  The RED for diflubenzuron
was issued in August, 1997 (EPA 738-R-97-008).  The chemical structure
and nomenclature of diflubenzuron are presented in Table 1.  The
physicochemical properties of the technical grade of diflubenzuron are
presented in Table 2.

Table.1.  Diflubenzuron Nomenclature.

Compound	

Common Name	Diflubenzuron

Trade and other Names	Dimilin, Vigilante, Micromite, Adept

IUPAC Name	1-(4-chlorophenyl)-3-(2,6-difluorobenzoyl)urea

CAS Name	N-[[(4-chlorophenyl)amino]carbonyl]-2,6-difluorobenzamide

CAS Registry Number	35367-38-5

End-Use Products (EP)	2 lb/gal FlC formulation; DIMILIN® 2L (EPA Reg.
No. 400-461);

25% WP formulation; DIMILIN® 25W (EPA Reg. No. 400-465);

80% G formulation; Micromite® 80WGS (EPA Reg. No. 400-487);

Regulated Metabolite	

Common name	4-chlorophenylurea (CPU)

Regulated Metabolite	

Common Name	4-chloroaniline (PCA)



Table 2.  Physicochemical Properties of Diflubenzuron.

Parameter	Value	Reference

Melting range	230-232 °C	  HYPERLINK
"http://www.arsusda.gov/acsl/services/ppdb/textfiles/DIFLUBENZURON" 
http://www.arsusda.gov/acsl/services/ppdb/textfiles/DIFLUBENZURON 

pH	Not available

	Density	Not available

	Water solubility (25 °C)	0.08 ppm

	Solvent solubility (25 °C) (ppm)	6.5 x 103     Acetone             

2 x 103        Acetonitrile        

2.4 x 104     Dioxane             

1.04 x 105   Dimethylformamide    

1.2 x 105     Dimethylsulfoxide   

1 x 103        Methanol            

6 x 102        Dichloromethane     

	Vapor pressure (25 °C)	1.2 x 10- 4 mPa

	Dissociation constant, pKa	Not available

	Octanol/water partition coefficient, Log(KOW)	3.89

	UV/visible absorption spectrum	Not available

	

860.1200 Directions for Use

A summary of the proposed end-use products is presented in Table 3. 
Table 4 lists the summary of proposed use patterns.

Table 3.  Summary of Proposed End-Use Products.



Trade Name	

Reg. No.	% ai (formulation)	Formulation Type	

Target New Crops	

Target Pests	Label Date

Dimilin® 2L	400-461	22%

(2 lb ai/gal)	Flowable concentrate (FlC)	Barley, oats, triticale, and
wheat, peanut, leafy Brassica, and turnip greens	Grasshoppers, cereal
leaf beetle, velvet bean caterpillar, Mexican bean beetle, green clover
worm, armyworms, lesser cornstalk borer, soybean looper (suppression)
Undated specimen label

Dimilin® 25W	400-465	25%	Wettable powder (WP)	Eggplant and okra
Foliage-feeding Lepidopteran insects	Undated specimen label

Micromite® 80WGS	400-487	80%	Water-dispersible granule	Pummelos	Citrus
rust mite, Lepidopterous miners, and citrus root weevil complex	Undated
specimen label



Table 4.  Summary of Proposed Directions for Use of Diflubenzuron.

Applic. Timing, Type, 

Equipment.	Formulation

[EPA Reg. No.]	Applic. Rate 

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

(lb ai/A)	PHI

(days)

Barley, Oats, Triticale, and Wheat

Foliar prior to boot stage

ULV (24-32 fl. oz/A)

Aerial (3-5 GPA)

Ground (5-15 GPA)	Use Directions and Limitations:  Use limited to crops
grown in Alaska, Colorado, Idaho, Montana, Nevada, Oregon, Utah,
Washington, Wyoming, Western North and South Dakota, and Western
Nebraska (West of Route 281 in ND, SD, & NE).  Do not apply after boot
stage of growth.  For control of grasshoppers, apply when pests have
reached the 2nd to 3rd nymphal stage of development.  For control of
cereal leaf beetle, apply at first sign of egg laying.

	2 lb/gal FlC

[400-461]	0.0625	1	0.0625	45 for grain and straw

Brassica Leafy Greens including Mustard Greens; Turnip Greens

Foliar

Ground (Min 30 GPA)	Use Directions and Limitations:  For control of
grasshoppers, apply when pests have reached the 2nd to 3rd nymphal stage
of development.  Reapply in 7-10 day intervals if nymphal hatchout or
crop re-infestations continue.

	2 lb/gal FlC

[400-461]	0.0625	4	0.25	7

Eggplant

Foliar

Ground (Min 30 GPA)	Use Directions and Limitations:  Allow a minimum of
7 days between any 2 applications.

	25% WP

[400-465]	0.125	Up to 5 treatments may be made as long as the maximum
seasonal rate of 0.375 lb ai/A is not exceeded.	7

Okra

Foliar

Ground (Min 30 GPA)	Use Directions and Limitations:  Allow a minimum of
7 days between any 2 applications.

	25% WP

[400-465]	0.125	Up to 5 treatments may be made as long as the maximum
seasonal rate of 0.375 lb ai/A is not exceeded.	7

Peanut

Foliar 

Aerial (3-5 GPA)

Ground (10-20 GPA)	Use Directions and Limitations:  Allow at least 14
days between any two applications.  Repeat applications if the egg
laying period is lengthy and/or another pest infestation occurs.

	2 lb/gal FlC

[400-461]	0.125	3	0.375	28

Pummelo

Foliar

Aerial (5-20 GPA)

Ground (50-1,000 GPA)

	Use Directions and Limitations:  Maintain a minimum of 90 days between
applications.  Do not harvest cover crops for livestock feed or graze
livestock in treated groves.

	80% WGS

[400-487]	0.3125	3	0.9375

(max yearly rate)	21



The following rotational crop restriction is specified on the undated
draft specimen labels of the 2 lb/gal FlC (Dimilin® 2L; EPA Reg. No.
400-461) and 25% WP (Dimilin® 25W; EPA Reg. No. 460-465) formulations: 
“Do not plant food or feed crops in DIMILIN treated soils within 1
month following last application, unless DIMILIN is authorized for use
on these crops.”

Conclusions.  The submitted labels are adequate to allow evaluation of
the residue data relative to the proposed uses except:  Barley, oats,
and wheat:  The petitioner should delete the proposed application method
using ULV (24-32 fl. oz/A) equipment.  Label revisions are requested to
specify appropriate PHIs based on the reviewed data.  Labels should be
revised to specify PHIs of 50 days for grain and straw, 3 days for
forage, and 15 days for hay.  Turnip greens:  The label should be
amended to prohibit use on dual purpose turnip cultivars or varieties
which produce a harvestable root.  Okra and eggplant:  The use
directions for okra and eggplant should be removed from the label. 
Revised Section Bs should be submitted.

860.1300 Nature of the Residue – Plants, Livestock & Fungi

Summary of Plant Metabolism Studies (DP# 272978, G. Kramer, 4/3/2001)

HED Metabolism Assessment Review Committee (MARC) Meetings of 2/20/2001
and 5/8/2001.

Residues of Concern for Cancer Risk Assessment (DP# 272976, G. Kramer
and G. Reddy, 5/31/2001)

The qualitative nature of the residue in plants, livestock and fungi is
adequately understood based on data from citrus, mushroom, rice,
soybean, poultry, and ruminant metabolism studies.  The HED MARC has
concluded that the residues of concern are diflubenzuron and its
metabolites PCA and CPU.

860.1340 Residue Analytical Methods

Tolerance enforcement methods

Residue Chemistry Chapter of the Diflubenzuron RED (DP# 209032, S.
Knizner, 3/15/1995)

DP# D285141 (G. Kramer, 9/6/2002)

Three enforcement methods for diflubenzuron are published in the
Pesticide Analytical Manual (PAM, Vol. II) as Methods I, II, and III. 
Method I is a GC/ECD method that determines diflubenzuron in plants as
derivatized PCA.  Method II is a GC/ECD method that can separately
determine residues of diflubenzuron, CPU and PCA in eggs, milk, and
livestock tissues, each as derivatized PCA.  Method III is a
high-performance liquid chromatography/ultraviolet (HPLC/UV) method that
determines diflubenzuron per se in eggs, milk, and livestock tissues. 
All three methods have undergone successful Agency validations.  The
Diflubenzuron RED stated that Methods I and II are the preferred
enforcement methods because they are easier to perform, have less
interference, and are more sensitive.

In conjunction with the approved rice petition (PP#8F4925), a new
analytical methodology for plant commodities was successfully validated
by an independent laboratory as well as by Agency chemists at ACB/BEAD,
and was forwarded to FDA for publication in PAM Vol. II as Roman Numeral
Methods.  T  SEQ CHAPTER \h \r 1 hese methods can separately determine
residues of diflubenzuron by GC/ECD, CPU by GC/ECD, and PCA by GC/MS
using an isotopically labeled internal standard and by summing the
response of the two ions.  The reported LOQ for diflubenzuron in/on rice
grain, straw, and bran is 0.01 ppm, and is 0.05 ppm in/on rice hull.  In
rice straw, the LOQ for CPU is 0.01 ppm and 0.005 ppm for PCA.

Data-collection methods

Samples of raw agricultural and processed commodities, taken from the
field, processing, and storage stability studies were separately
analyzed for residues of diflubenzuron, CPU, and PCA using methods,
which are similar or based on method submissions previously deemed
acceptable by HED.  The data-collection methods were adequately
validated, and method recoveries were generally within the acceptable
range of 70-120%.  Complete descriptions of these methods along with
method recoveries are presented in the individual study DERs.

860.1360 Multiresidue Methods

PAM Vol. I, Appendix II 

DP# 194722, L. Edwards, 9/17/93:  Transmission of MRM data for
diflubenzuron to FDA.

DP# 254273, J. Rowell, 12/15/1998:  Transmission of MRM data for PCA and
CPU to FDA

  SEQ CHAPTER \h \r 1 The FDA PESTDATA database dated 1/94 (PAM Vol. I,
Appendix II) contain no information on diflubenzuron recovery using
Multiresidue Methods PAM, Vol. I Sections 302, 303, and 304. However,
the registrant has submitted Multiresidue testing data for diflubenzuron
that HED has forwarded to the FDA.  In addition, the results of
Multiresidue Method testing of PCA and CPU have been submitted and
forwarded to FDA.  Neither PCA nor CPU was adequately recovered.

860.1380 Storage Stability

The storage intervals and conditions of samples from the crop field
trials and processing studies submitted to support these petitions are
presented in Table 5.



Table 5.  Storage Conditions and Intervals of Samples from Crop Field
Trial and Processing Studies.  



Matrix 	Storage Temperature

(°C)	Actual Storage Duration (Days)	

Interval of Demonstrated Storage Stability

Barley and Wheat Field Trials (MRID 46609501)

Grain	<0	169-189	Diflubenzuron is stable in barley grain for 296 days,
barley straw for 301 days, wheat forage for 422 days, and wheat hay for
337 days.  CPU is stable in barley grain for 348 days and wheat forage
for 267 days but showed a decline in barley straw after 299 days and in
wheat hay after 355 days.  PCA was reasonably stable in barley straw
after 302 days, marginally stable in wheat hay after 359 days, and
unstable in barley grain and wheat forage after 345 days.

Straw	<0	166-232

	Forage	<0	183-262

	Hay	<0	205-245

	Wheat Processing Study (MRID 46609501)

Wheat grain	<0	100-105	Diflubenzuron is stable for 296 days, CPU for 348
days, and PCA for 293 days in the RAC (wheat grain). 

Shorts	<0	90-113	The available storage stability data (DP# 244487, G.
Kramer, 2/17/1999) for rice bran may be translated to wheat bran  SEQ
CHAPTER \h \r 1 .

Middlings	<0	90-113

	Flour	<0	96-111

	Bran	<0	92-98

	Germ	<0	96-321

	Aspirated Grain	<0	92-98

	Mustard Greens Field Trials (MRID 46609601)

Mustard greens	<0	422-520	Diflubenzuron is stable in mustard greens for
up to 422 days and CPU for up to 520 days.  PCA was unstable after 423
days of storage.

Peanut Field Trials (MRID 46609401) 

Peanut nutmeat	<0	244-408	Diflubenzuron is stable in nutmeat for up to
295 days; however, CPU and PCA exhibited 33-37% reduction in residues
after 421 and 289 days.  A similar profile was observed for peanut hay. 
Diflubenzuron is stable in hay for up to 356 days; CPU and PCA exhibited
25-71% reduction in residues after 484 and 338 days of frozen storage,
respectively.

Peanut hay	<0	323-481

	Peanut Processing Study (MRID 46609401)

Peanut meal 	<0	254-639	Diflubenzuron is stable in meal and oil
fortified at 0.5 ppm and stored for 643 and 365 days, respectively.  CPU
is stable in meal and oil stored 645 and 294 days, respectively.  PCA is
stable in meal and oil stored 488 and 286 days, respectively.

Peanut oil	<0	252-276

	

Storage stability data

DP 244487; G. Kramer, 2/17/1999

To validate sample storage conditions and intervals, the petitioner
included storage stability data in the respective magnitude of the
residue study submissions.  These data are summarized below.

The submitted storage stability study for small grains indicate that
diflubenzuron is reasonably stable in barley grain for 296 days, barley
straw for 301 days, wheat forage for 422 days, and wheat hay for 337
days.  CPU was reasonably stable in barley grain for 348 days and wheat
forage for 267 days but showed a decline in barley straw (average
corrected stored recovery of 34%) after 299 days and in wheat hay
(average corrected stored recovery of 30%) after 355 days. PCA was
reasonably stable in barley straw after 302 days, marginally stable in
wheat hay after 359 days, and unstable in barley grain (average
corrected stored recovery of 33%) and wheat forage (average corrected
stored recovery of 39%) after 345 days.

No storage stability data for wheat processed commodities are available.
 The available storage stability data for rice processed commodities may
be translated to wheat processed fractions.  These data indicate that  
SEQ CHAPTER \h \r 1 diflubenzuron and CPU are stable in the processed
commodities of rice over a 12-month period.  PCA is unstable, degrading
significantly after 1 month.

The submitted storage stability data for mustard greens show that
diflubenzuron is reasonably stable in frozen mustard greens for up to
422 days.  CPU was also found to be stable in frozen mustard greens for
up to 520 days.  However, residues of PCA were unstable (average
corrected stored recovery of 17%) after 423 days of storage.

The submitted storage stability data for peanuts indicate that
diflubenzuron is relatively stable in/on nutmeat for up to 295 days;
however, CPU (average corrected stored recovery of 67%) and PCA (average
corrected stored recovery of 63%) exhibited 33-37% reduction in residues
after 421 and 289 days of frozen storage, respectively.  A similar
storage stability profile was observed for peanut hay.  Diflubenzuron is
relatively stable in/on hay for up to 356 days; CPU (average corrected
stored recovery of 29%) and PCA (average corrected stored recovery of
75%) exhibited 25-71% reduction in residues after 484 and 338 days of
frozen storage, respectively.

The submitted storage stability data for peanut processed commodities
indicate that diflubenzuron is stable in meal and oil fortified at 0.5
ppm and stored for 643 and 365 days, respectively.  CPU is stable in
meal and oil stored for 645 and 294 days, respectively.  PCA is stable
in meal and oil stored for 488 and 286 days, respectively.

Conclusions:  The submitted storage stability data indicate that
diflubenzuron is reasonably stable in/on the RACs of barley, wheat,
peanut, and mustard greens as well as the in the processed commodities
of peanut.  However, CPU exhibited instability in a few commodities and
PCA exhibited instability in many commodities.  The storage stability
studies suggest that residues of CPU and PCA should be corrected in
order to determine the residue levels that were present at the time of
sample collection.  However, HED has determined that correction of CPU
and PCA residues for degradation during storage would not have a
significant effect on the results of the submitted field trials because
individual residues of the metabolites in/on treated RAC samples were
mostly below the respective LOQs. 

Additional storage stability data for wheat processed commodities
(except bran) are requested to validate the storage conditions and
intervals of samples from the submitted wheat processing study.  The
available storage stability data for rice bran may be translated to
wheat bran; the petitioner is only requested to generate storage
stability data for wheat flour, middlings, shorts, and germ.

860.1480 Meat, Milk, Poultry, and Eggs

Maximum Theoretical Dietary Burdens (MTDB)

There are ruminant and/or poultry feed items associated with the
proposed uses of diflubenzuron on barley, oats, wheat, and peanuts. 
Although there are many plausible ways of estimating the MTDB of
diflubenzuron to livestock, the calculation of dietary burdens,
presented in Table 6, largely incorporates the feed items associated
with these petitions.  The calculated dietary burdens should be
considered tentative because additional field trial data are being
requested for some commodities including peanut hay; a new peanut
processing study is also requested.  The MTDBs of diflubenzuron are 22.2
ppm for beef cattle, 34.8 ppm for dairy cattle, 0.052 ppm for poultry,
and 0.058 ppm for hog.

Table 6.  Calculation of Maximum Theoretical Dietary Burdens of
Diflubenzuron Residues to Livestock.

Feedstuff	% Dry Matter1	% Diet1	Recommended Tolerance (ppm)	Dietary
Contribution (ppm)2

Beef Cattle

Peanut hay	85	25	553	16.2

Wheat grain	89	50	0.06	0.03

Grass forage 	25	25	6.0	6.00

TOTAL BURDEN

100

22.2

Dairy Cattle

Peanut hay	85	50	553	32.4

Wheat grain	89	40	0.06	0.03

Grass forage 	25	10	6.0	2.40

TOTAL BURDEN

100

34.8

Poultry

Wheat grain	89	80	0.06	0.048

Rice grain	88	20	0.02	0.004

TOTAL BURDEN

100

0.052

Hog

Wheat grain	89	80	0.06	0.048

Soybean seed	89	20	0.05	0.010

TOTAL BURDEN

100

0.058

1  Table 1 (OPPTS Guideline 860.1000).  

2  Contribution = ([tolerance /% DM] X % diet) for beef and dairy
cattle; contribution = ([tolerance] X % diet) for poultry and hog. 

3  Tentatively assessed tolerance level for peanut hay based on input of
limited residue data into HED’s Tolerance Spreadsheet; additional
confirmatory field trials on peanuts are requested.

Livestock Feeding Studies

Residue Chemistry Chapter of the Diflubenzuron Registration Standard
(11/84)

Residue Chemistry Chapter of the Diflubenzuron RED (DP# 209032, S.
Knizner, 3/15/1995)

No livestock feeding studies were submitted with these petitions.    SEQ
CHAPTER \h \r 1 Numerous diflubenzuron feeding studies have been
reviewed previously by HED.  Those that are the most relevant to the
current petitions are discussed below.

In one cattle study, lactating cows were dosed orally twice a day with
diflubenzuron at either 25 (0.7x) or 250 (7x) ppm in the diet for up to
28 consecutive days.  Residues of diflubenzuron per se were
nondetectable (<0.05 ppm) in milk from both feeding levels sampled
following 1 to 28 days of dosing.  Residues of diflubenzuron per se were
also nondetectable (<0.05 ppm) in the fat, muscle, liver, and kidneys of
cows sacrificed after 8, 18, and 28 days of dosing at 25 (0.7x) ppm. For
cows sacrificed after dosing at 250 (7x) ppm for 8, 18 and 28 days,
residues of diflubenzuron per se were nondetectable (<0.05 ppm) in the
muscle and kidney, 0.06-0.08 ppm in fat, and 0.09-0.1 ppm in liver.

In the third study, four dairy calves were fed diflubenzuron at a rate
of 2.8 mg ai/kg body weight for 4-5 months and two were sacrificed. 
Then three others were fed at 1 mg ai/kg body weight for another year
and sacrificed.  The 2.8 and 1.0 mg/kg doses were equivalent to
approximately 180 (5x) and 65 (2x) ppm, respectively, in the diet. 
Following dosing at 180 ppm (5x), residues of diflubenzuron were 0.02
ppm in liver and kidney, 0.04-0.08 ppm in fat, and <0.02 ppm in muscle. 
Residues of diflubenzuron per se were nondetectable (<0.02 ppm) in
tissues from livestock after dosing at 65 ppm (2x).

Acceptable data are also available for residues of diflubenzuron in
eggs, meat, meat byproducts, and fat of poultry.  The Residue Chemistry
Chapter of the Diflubenzuron Registration Standard (11/84) and the
Addendum to the Diflubenzuron Registration Standard (12/84) cited five
feeding studies on poultry.  In one study, laying hens were orally dosed
via capsule for 1-28 consecutive days at 0.05 (1x), 0.5 (10x), and 5
(100x) ppm of [14C]diflubenzuron in the diet.  Hens were sacrificed at
3- to 7-day intervals throughout the study.  Residues of diflubenzuron
per se were 0.21 ppm in fat after dosing at 5 ppm (100x) for 7 days. 
After 24 days of dosing at 5 ppm (100x), residues of diflubenzuron per
se were 0.05 ppm in muscle and kidney, 0.16 ppm in liver, and 0.14 ppm
in eggs.

2 weeks and remained constant at 0.3-0.6 ppm for the remainder of
the dosing period.  Hens were sacrificed after a 3-day withdrawal
period.  For BBR/RIR hens, average residues of diflubenzuron were 1.17
ppm in fat, 0.12 ppm in liver, and nondetectable (<0.01 ppm) in muscle
at the end of the dosing period.  For WL hens, average residues of
diflubenzuron were 1.85 ppm in fat, 0.45 ppm in liver, and nondetectable
(<0.01 ppm) in muscle at the end of the dosing period.

Male Hubbard chickens in another study were dosed for 98 days with feed
containing diflubenzuron at 2.5 and 250 ppm, five hens at each level. 
At the 2.5 ppm feeding level (50x), residues of diflubenzuron per se
were 2.2-6.9 ppm in fat, 0.09-0.45 ppm in muscle and skin, and 0.06-0.72
ppm in liver.  At the 250 ppm feeding level (5000x), residues of
diflubenzuron were 23-62 ppm in fat, 0.9-3.3 ppm in muscle and skin, and
0.8-3.8 ppm in liver.

Conclusions.  There are ruminant and/or poultry feed items associated
with the proposed uses of diflubenzuron on barley, oats, wheat, and
peanuts.  The calculated maximum theoretical dietary burdens (22.2 ppm
for beef cattle, 34.8 ppm for dairy cattle, 0.052 ppm for poultry, and
0.058 ppm for hog), resulting from the proposed uses, are supported by
previously-submitted livestock feeding studies.  HED concludes that the
current tolerances on meat, milk, poultry, and eggs are adequate to
cover the added residues resulting from the proposed uses.

860.1500 Crop Field Trials

Barley and Wheat

46609501.de1.doc

Seven field trials on barley (2 winter and 5 spring varieties) and three
trials on wheat (1 winter and 2 spring varieties) were conducted in EPA
Zones 5, 7, 8 and 11 between the 2002 and 2003 growing seasons.  At each
location, diflubenzuron (2 lb/gal FlC) was applied once to barley and
wheat fields as a broadcast foliar application at 0.0592-0.0642 lb ai/A
(1x) during crop development (pre-boot, pre-stem elongation, jointing,
or Feekes 8 growth stage).  A single control and duplicate treated
samples of mature grain and straw were harvested from each site at 50-76
days after treatment (DAT).  Hay was harvested from each site at 15-39
DAT, and wheat forage was harvested at 3-12 DAT.   SEQ CHAPTER \h \r 1 
The collected samples of grain, straw, forage, and hay were stored
frozen for up to 189, 232, 262 and 245 days, respectively, prior to
residue analysis.  The storage intervals and conditions are supported by
adequate storage stability data.

The harvested commodities of barley and wheat were analyzed for residues
of diflubenzuron, CPU, and PCA using HPLC/UV, GC/MS, and GC/MS with
selected ion monitoring, respectively.  These methods, which are similar
or based on method submissions previously deemed acceptable by HED, were
adequately validated in conjunction with the field sample analyses.  The
lowest limit of method validations (LLMV) are 0.05 ppm for diflubenzuron
and 0.005 ppm for CPU and PCA.

The results of the field trials (Table 7) indicate that following a
single foliar application of the 2 lb/gal FlC formulation, the combined
residues of diflubenzuron, CPU and PCA were:  0.13-1.47 ppm in/on barley
hay (15-39 day PHI); <0.06 ppm in/on barley grain (50-76 day PHI);
<0.06-0.58 ppm in/on barley straw (50-76 day PHI); 1.17-3.97 ppm in/on
wheat forage (3-12 day PHI); 0.11-1.31 ppm in/on wheat hay (28-32 day
PHI); <0.06 ppm in/on wheat grain (56-62 day PHI); and <0.06-1.04 ppm
in/on wheat straw (56-62 day PHI).  The combined highest-average field
trial (HAFT) values were:  1.40 ppm for barley hay; <0.06 ppm for barley
grain; 0.57 ppm for barley straw, 3.80 ppm for wheat forage; 1.28 ppm
for wheat hay; <0.06 ppm for wheat grain; and 0.91 ppm for wheat straw.

Table 7.  Summary of Residue Data from Barley and Wheat Field Trials
with Diflubenzuron.



Commodity	Total Applic. Rate (lb ai/A)	PHI (days)	Combined Residues of
Diflubenzuron, CPU, and PCA (ppm)1



	N	Min.	Max.	HAFT2	Median	Mean	Std. Dev.

Barley, hay	0.0592-0.0629	15-39	14	0.13	1.47	1.40	0.68	0.67	0.38

Barley, grain

50-76	14	<0.06	<0.06	<0.06	<0.06	<0.06	0.0

Barley, straw

50-76	14	<0.06	0.58	0.57	0.32	0.33	0.20

Wheat, forage	0.0619-0.0642	3-12	6	1.17	3.97	3.80	2.57	2.70	1.00

Wheat, hay

28-32	6	0.11	1.31	1.28	0.89	0.78	0.50

Wheat, grain

56-62	6	<0.06	<0.06	<0.06	<0.06	<0.06	0.0

Wheat, straw

56-62	6	<0.06	1.04	0.91	0.30	0.43	0.40

1  The LLMV is 0.05 ppm for residues of diflubenzuron, and 0.005 ppm for
residues of CPU and PCA.

2   HAFT = Highest-Average Field Trial. 

Conclusions:  The submitted field trial data for barley and wheat
commodities reflect the proposed crop use pattern and are supported by
acceptable storage stability data.  Samples were analyzed for
diflubenzuron residues of concern using adequate data-collection
methods.  Geographic representation of residue data is adequate for the
purpose of seeking regional registration of diflubenzuron on crops grown
in Alaska, Colorado, Idaho, Montana, Nevada, Oregon, Utah, Washington,
Wyoming, Western North and South Dakota, and Western Nebraska (West of
Route 281 in ND, SD, & NE).  Note that HED previously approved the
number and location of these field trials (e-mail correspondences
between J. Corley of IR-4 and G. Herndon, 11/25/03).

The submitted data for barley grain and wheat grain showed that residues
were below the respective LLMVs for each analyte (with a combined LLMV
of <0.06 ppm) in/on treated samples.  The proposed tolerance of 0.06 ppm
for barley grain and wheat grain are appropriate pending label revision
to specify a 50-day PHI for barley grain and wheat grain.

The submitted data for the remainder of barley and wheat commodities
were entered into the tolerance spreadsheet (see Appendix I).  Using the
rounding procedure as outlined in the Guidance for Setting Pesticide
Tolerances Based on Field Trial Data SOP, HED recommends tolerance
levels of 3.0 ppm for barley hay, 1.8 ppm for barley straw, 7.0 ppm for
wheat forage, 6.0 ppm for wheat hay, and 3.5 ppm for wheat straw. 
Barley forage is not listed in Table 1 of OPPTS 860.1000; therefore,
this entry should be removed from the Section F.  

Label revisions are requested to specify appropriate PHIs based on the
reviewed data.  Labels should be revised to specify PHIs of 50 days for
grain and straw, 3 days for forage, and 15 days for hay.

The submitted residue data for wheat commodities may be translated to
oat commodities because the registered uses on small grains are
identical and proposed use is geographically limited.  This
recommendation is contingent upon the requested label revisions.

The proposed use on triticale is supported by the submitted data for
wheat as per 40 CFR 180.1.

Pummelo

No residue data were submitted in support of the proposed tolerance for
pummelo.  The petitioner requests translation of the available data from
citrus fruits to pummelo.  As pummelos are to be included in the
definition of grapefruit (Reviewer’s Guide and Summary..., B.
Schneider, 6/14/02), this data translation is appropriate. 

Conclusions:  The established grapefruit tolerance may be used to
support the requested tolerance of 0.5 ppm for residues in/on pummelos. 

Mustard Greens

46609601.der.doc

Eight field trials on mustard greens were conducted in EPA Zones 2, 3,
5, 6, and 10 during the 2001 growing season.  At each location,
diflubenzuron (2 lb/gal FlC) was applied four times (except for one
trial site where only three treatments were made) as broadcast foliar
applications using ground equipment at 0.061-0.066 lb ai/A/application
for a total rate of 0.19-0.26 lb ai/A (0.8-1x).  Treatments were made
during the crop’s vegetative growth stage at a retreatment interval of
8-15 days.  Duplicate control and treated samples of mature mustard
greens were harvested from each site at 6-8 DAT.   SEQ CHAPTER \h \r 1 
Mustard green samples were stored frozen up to 520 days prior to residue
analysis, an interval supported by available storage stability data.

The harvested samples of mustard greens were analyzed for residues of
diflubenzuron, CPU, and PCA using HPLC/UV, GC/ECD and GC/MSD methods,
respectively.  These methods, which are similar or based on method
submissions previously deemed acceptable by HED, were adequately
validated in conjunction with the field sample analyses.  The LOQs are
0.05 ppm for diflubenzuron, 0.01 ppm for CPU, and 0.005 ppm for PCA.

The results (Table 8) show that the combined residues of diflubenzuron,
CPU, and PCA were <0.065 ppm-7.07 ppm in/on mustard greens harvested 6-8
days following the last of 3 to 4 foliar treatments of a 2 lb/gal FlC
test formulation for a total application rate of 0.19-0.26 lb ai/A.  The
HAFT was 6.85 ppm and the average combined residues were 2.05 ppm.

No residue decline data were submitted.  HED generally requires residue
decline data when a pesticide is applied when the edible portion of the
crop has formed and/or it is clear that quantifiable residues may occur
in/on food or feed commodities at the earliest harvest time.  However,
decline data were previously submitted with the stone fruit residue
trials (45252206.der.wpd).  These data do demonstrate that residues
generally declined from the 14-day PHI to the 28-day PHI.  HED is
willing to translate these data to mustard greens and concludes that
additional residue decline data on mustard greens will not be requested.
 

Table 8.  Summary of Residue Data from Mustard Green Field Trials with
Diflubenzuron.

Commodity	Total Applic. Rate (lb ai/A)	PHI (days)	Combined Residues of
Diflubenzuron, CPU, and PCA (ppm)1



	n	Min.	Max.	HAFT2	Median	Mean	Std. Dev.

Mustard Greens	0.19-0.26	6-8	16	<0.065	7.07	6.85	1.23	2.05	2.05

1  The LOQ is 0.05 ppm for diflubenzuron, 0.01 ppm for CPU, and 0.005
ppm for PCA.

2  HAFT = Highest-Average Field Trial. 

Conclusions:  The submitted field trials for mustard greens, the
representative commodity of the Brassica leafy greens (subgroup 5B),
reflect the proposed crop use pattern and are supported by acceptable
storage stability data.  Geographic representation of residue data for
mustard greens is adequate.  Samples were analyzed for diflubenzuron
residues of concern using adequate data-collection methods.  The
submitted data for mustard greens were entered into the tolerance
spreadsheet (see Appendix I).  Using the rounding procedure as outlined
in the Guidance for Setting Pesticide Tolerances Based on Field Trial
Data SOP, HED recommends a tolerance level of 9.0 ppm for residues in/on
Brassica leafy greens (subgroup 5B).

Turnip Greens

Turnip greens will be removed from Crop Group 2:  Leaves of root and
tuber vegetables group, and will become a member of Crop Subgroup 5B: 
Leafy Brassica greens (Reviewer’s Guide and Summary..., B. Schneider,
6/14/02).  Forage turnip varieties grown for livestock feed uses only
will remain in Crop Group 2:  Leaves of root and tuber vegetables group.
 As mustard greens are the representative commodity of the Brassica
leafy greens (subgroup 5B), HED recommends a tolerance level of 9.0 ppm
for residues in/on turnip greens.  However, the label should be amended
to prohibit use on dual purpose turnip cultivars or varieties which
produce a harvestable root.

Eggplant

No residue data were submitted in support of the proposed tolerance for
eggplant.  The petitioner requests translation of the available data
from pepper to eggplant.  However, HED does not generally translate
residue data among members of a crop group unless a crop group tolerance
is established.

Conclusions:  The available data for peppers may not be translated to
support the requested tolerance of 1.0 ppm for residues in/on eggplant. 
Thus, the proposed tolerance for eggplant should be withdrawn and the
use directions for eggplant removed from the label until adequate
eggplant residue data are available or a crop group tolerance for
fruiting vegetables is established.

Okra

No residue data were submitted in support of the proposed tolerance for
okra.  The petitioner requests translation of the available pepper data
to okra and has included in the administrative materials of the petition
a technical proposal to amend the definition of fruiting vegetables
(except cucurbits) to add okra.  However, HED does not generally
translate residue data among members of a crop group unless a crop group
tolerance is established. 

Conclusions:  The available data for peppers may not be translated to
support the requested tolerance of 1.0 ppm for residues in/on okra. 
Thus, the proposed tolerance for okra should be withdrawn and the use
directions for okra removed from the label until adequate okra residue
data are available or a crop group tolerance for fruiting vegetables is
established.

Peanut

46609401.de1.doc

Twelve peanut field trials were conducted in EPA Zones 2, 3, and 6
during the 2001 growing season.  At each trial location, diflubenzuron
(2 lb/gal FlC) was applied three times as broadcast foliar applications
using ground equipment at 0.121-0.132 lb ai/A/application for a total
rate of 0.373-0.385 lb ai/A (1x).  The first application was at first
bloom, the second was 14 (± 1) days after the first, and the third was
28 (± 1) days before harvest at nine sites, 20 days at two sites and 26
days at one site.  A single control and single or duplicate treated
samples of peanuts and peanut hay were harvested from each site at 20-28
DAT.   SEQ CHAPTER \h \r 1  Additional samples of peanut nutmeat and hay
were collected from one site at 15, 20, 29, and 35 DAT to generate
residue decline data.  All samples were stored frozen for up to 481 days
prior to residue extraction and analysis, an interval partially
supported by available storage stability data.

The harvested samples were analyzed for residues of diflubenzuron using
HPLC/UV method for nutmeat and hay, for residues of CPU using HPLC/MS/MS
or UV for nutmeat or GC/MS methods for hay, and for residues of PCA
using GC/MS method for nutmeat and hay.  These methods, which are
similar or based on method submissions previously deemed acceptable by
HED, were adequately validated in conjunction with the field sample
analyses.

The results from three field sites (Trial IDs TN03, GA01, and GA03)
showed possible sample contamination since residues of diflubenzuron or
CPU in/on control samples of peanut nutmeat were equal to or higher than
treated samples.  No adequate explanation was provided except a
statement from the petitioner commenting that the magnitude of residues
in/on control samples which bore quantifiable residues was low relative
to the residues in/on treated samples.

When samples from Trial IDs TN03, GA01, and GA03 are excluded, the
combined residues of diflubenzuron, CPU and PCA ranged <0.060-<0.070 ppm
in/on 18 samples of peanut nutmeat and 1.12-18.46 ppm in/on 11 samples
of peanut hay that were harvested 20-28 days following the last of three
foliar treatments of a 2 lb/gal FlC test formulation for a total
application rate of 0.373-0.385 lb ai/A; see Table 9.  The HAFT values
were <0.070 ppm for nutmeat and 18.46 ppm for hay.  The average combined
residues were 0.06 ppm for nutmeat and 7.14 ppm for hay.

The submitted residue decline data for peanut nutmeat is inconclusive,
and a trend could not be established because residues of the parent and
its metabolites were all below the respective LOQs from samples
collected at PHIs of 15, 20, 29, and 35 days.  Although detectable
residues in peanut hay were observed from the decline trial, a
meaningful trend in residue decline could not also be established since
residue levels fluctuated at various sampling intervals.

Table 9.  Summary of Residue Data from Peanut Field Trials with
Diflubenzuron.



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



	n	Min.	Max.	HAFT2	Median	Mean	Std. Dev.

Nutmeat	0.373-0.385	20-28	18	<0.060	<0.070	<0.070	0.060	0.060	0.0

Hay

	11	1.12	18.46	18.46	7.17	7.14	6.24

1   The LOQ is 0.05 ppm for residues of diflubenzuron, and 0.005 ppm for
residues of CPU and PCA in nutmeat.

2   HAFT = Highest Average Field Trial. 

Conclusions:  The submitted field trials for peanuts reflect the
proposed crop use pattern and are supported by acceptable storage
stability data.  However, geographic representation of residue data for
is inadequate because the results from three trials were invalidated
because of possible sample contamination.  Confirmatory residue data
from additional three peanut field trials conducted in Zone 2 are
requested.  Although geographic representation of data is incomplete,
the residue values reported for peanut hay were entered into HED’s
tolerance spreadsheet.  The residue values for peanut nutmeat were not
entered into the tolerance spreadsheet because the combined residues
ranged from <0.060 to <0.070 ppm.  Based on the available data, HED
tentatively recommends tolerance levels of 0.10 ppm for residues in/on
peanut nutmeat and 55 ppm for residues in/on peanut hay.

860.1520 Processed Food and Feed

Peanut

46609401.de2.doc

In a field trial conducted during the 2001 growing season in TX,
diflubenzuron (2 lb/gal FlC) was applied to peanuts as three broadcast
foliar applications during the crop’s developmental stage at ~0.125 lb
ai/A/application for a total rate of 0.379 lb ai/A (1x the field rate). 
Single bulk samples of untreated and treated peanuts were harvested at
commercial maturity, 29 DAT.  The harvested peanuts were dried, shelled,
and processed into meal and refined oil using simulated commercial
practices.  Prior to analysis, peanut nutmeat, meal, and oil were stored
frozen for 244-639 days; the storage intervals are supported by the
concurrent storage stability data.

The peanut nutmeat and its processed commodities (meal and refined oil)
were analyzed for residues of diflubenzuron using an HPLC/UV method, for
residues of CPU using an HPLC/MS/MS or UV method, and for residues of
PCA using a GC/MS method.  These methods, which are similar or based on
method submissions previously deemed acceptable by HED, were adequately
validated in conjunction with the peanut sample analyses.

The results (Table 10) show that combined residues of diflubenzuron,
CPU, and PCA were below the combined method LOQ (<0.06 ppm) in/on peanut
nutmeat treated at a seasonal rate of 0.379 lb ai/A.  Following
processing of the treated nutmeat, the combined residues were below the
method LOQs (<0.525 ppm) in peanut meal and <0.066 ppm (below the LOQ
for diflubenzuron and PCA, and 0.011 ppm for CPU) in peanut oil. 
Processing factors for meal and oil could not be reliably calculated due
to differing LOQs and <LOQ residues in all matrices (raw and
unprocessed).  Table 1 of OPPTS 860.1520 reports that the maximum
theoretical concentration factor (by crop) is 3x for peanuts.

Table 10.  Residue Data from Peanut Processing Study with Diflubenzuron.

RAC	Processed Commodity	Total Rate

(lb ai/A) 	PHI 

(days)	Diflubenzuron + CPU + PCA = 

Combined Residues (ppm)	Processing Factor

(Combined Residues)

Peanut	Nutmeat (RAC)	0.379	29	<0.05 + <0.005 + <0.005 = <0.06	--

	Meal

	<0.5 + <0.02 + <0.005 = <0.525	NC1

	Refined oil

	<0.05 + 0.011 + <0.005 = <0.066	NC

1  Processing factors could not reliably be calculated (NC) because most
residues were below the respective LOQ for that matrix.

≥3x, which is the maximum theoretical concentration factor (by crop)
for peanuts.  The meal samples from this study should be analyzed with a
method which has a LOQ for diflubenzuron which is comparable to that of
the RAC (0.05 ppm).  Pending receipt of these data, HED concludes that
the proposed tolerance of 0.2 ppm for residues in/on peanut oil is
appropriate (HAFT residue (<0.06 ppm; see Table 9) multiplied by the
maximum theoretical concentration factor of 3x).

Wheat

46609501.de2.doc

In a field trial conducted during the 2002 growing season in WA,
diflubenzuron (2 lb/gal FlC) was applied to a wheat crop (pre-booting
growth stage) as one broadcast foliar application at rates of 0.066 or
0.646 lb ai/A (1x and 10x the field rate, respectively).  Single bulk
samples of control and treated wheat grain were harvested at commercial
maturity, 83 DAT.  Wheat grain was processed into aspirated grain, germ,
bran, flour, shorts and middlings using simulated commercial procedures.
 

Prior to analysis, wheat grain and processed products were stored frozen
for up to 90-113 days, and one wheat germ sample was stored for up 321
days prior to analysis of diflubenzuron.  The storage conditions and
intervals of processed samples are marginally supported by storage
stability data.  The available storage stability data for rice bran may
be translated to wheat bran; however, the petitioner is requested to
generate storage stability data for wheat flour, middlings, shorts, and
germ.

Samples of wheat grain and its processed commodities were analyzed for
residues of diflubenzuron, CPU, and PCA, using HPLC/UV, GC/MS, and GC/MS
with selected ion monitoring, respectively.  These methods, which are
similar or based on method submissions previously deemed acceptable by
HED, were adequately validated in conjunction with the field sample
analyses.  The LLMV is 0.05 ppm for diflubenzuron and 0.005 ppm for CPU
and PCA in all wheat matrices.

The results (Table 11) show that following one application of the test
formulation at 0.066 lb ai/A (1x), individual residues of diflubenzuron,
CPU, and PCA were each below the respective LOQ in/on the RAC (wheat
grain) for a combined total of <0.06 ppm.  The combined residues were
<0.06 ppm in shorts, middlings, flour, bran, and germ, and were <2.104
ppm in aspirated grain fractions.  These data indicate that the combined
residues did not concentrate in all processed fractions of wheat but did
concentrate in aspirated grain fractions.  The calculated processing
factor for wheat aspirated grain fraction following processing of
1x-treated wheat grain is >35x.

Following one application of the test formulation at 0.646 lb ai/A
(10x), individual residues of diflubenzuron, CPU, and PCA were 0.147
ppm, <0.005 ppm, and <0.005 ppm, respectively in/on the RAC (wheat
grain) for a combined total of <0.157 ppm.  The combined residues were
<0.085 ppm in shorts, <0.06 ppm in middlings, <0.06 ppm in flour, <0.104
ppm in bran, <0.061 ppm in germ, and <28.069 ppm in aspirated grain
fractions.  These data also indicate that the combined residues did not
concentrate in all processed fractions of wheat but did concentrate in
aspirated grain fractions.  The calculated processing factor for wheat
aspirated grain fraction following processing of 10x-treated wheat grain
is 180x.

Table 11.  Residue Data from Wheat Processing Study with Diflubenzuron.

RAC	Processed Commodity	Total Rate

(lb ai/A) 	PHI 

(days)	Diflubenzuron + CPU + PCA = 

Combined Residues (ppm)	Processing Factor

(Combined Residues)

Grain	RAC	0.066	83	<0.05 + <0.005 + <0.005 = <0.06	--

	Shorts

	<0.05 + <0.005 + <0.005 = <0.06	1x

	Middlings

	<0.05 + <0.005 + <0.005 = <0.06	1x

	Flour

	<0.05 + <0.005 + <0.005 = <0.06	1x

	Bran

	<0.05 + <0.005 + <0.005 = <0.06	1x

	Germ

	<0.05 + <0.005 + <0.005 = <0.06	1x

	Aspirated grain

	2.094 + <0.005 + <0.005 = <2.104	>35x

Grain	RAC	0.646	83	0.147 + <0.005 + <0.005 = <0.157	--

	Shorts

	0.075 + <0.005 + <0.005 = <0.085	0.54x

	Middlings

	<0.05 + <0.005 + <0.005 = <0.06	0.38x

	Flour

	<0.05 + <0.005 + <0.005 = <0.06	0.38x

	Bran

	0.094 + <0.005 + <0.005 = <0.104	0.66x

	Germ

	0.051 + <0.005 + <0.005 = <0.061	0.42x

	Aspirated grain

	27.920 + 0.144 + <0.005 = <28.069	180x



Conclusions:  The wheat processing study is acceptable pending
submission of additional storage stability data.  The combined residues
of diflubenzuron and its CPU and PCA metabolites do not appear to
concentrate in shorts, middlings, flour, bran, and germ processed from
wheat grain treated at 1x and 10x the field rate.  The combined
residues, however, concentrated >35x and 180x in aspirated grain
fractions processed from wheat grain treated at 1x and 10x,
respectively.

The maximum diflubenzuron residues of concern expected in wheat
aspirated grain fractions is 6.42 ppm which is derived by multiplying
the HAFT residue (<0.06 ppm; see Table 7) with the processing factor
generated from RAC samples with quantifiable residues (180x).  Based on
this calculation, HED recommends a tolerance for aspirated grain
fractions at 11 ppm.  

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

Analytical standards for diflubenzuron and its metabolites CPU and PCA
are currently available in the National Pesticide Standards Repository
[6/16/2006 e-mail communication between D. Wright of ACB/BEAD and D.
Martinez of Dynamac].  

860.1850 Confined Accumulation in Rotational Crops

MRID 43274101 (DP# 205481, S. Knizner, 2/2/1995)

  SEQ CHAPTER \h \r 1 The nature of the residue in rotational crops is
adequately understood for purposes of reregistration (Residue Chemistry
Chapters for the RED document, 3/15/95).  Although the available
confined rotational crop study was inadequate to fully satisfy GLN 165-1
reregistration requirements, another confined rotational crop study will
not be requested because the study allowed HED to make regulatory
conclusions regarding the need for limited rotational-crop studies and
to comment on the appropriateness of the currently established PBIs on
diflubenzuron end-use product labels.

860.1900 Field Accumulation in Rotational Crops

MRID 44689703 (DP#s 244487, 251221, 251609, 253041, 253043; G. Kramer,
2/17/99)

≤0.375 lb ai/A, the proposed PBI of 30 days is appropriate.

860.1550 Proposed Tolerances

The HED MARC (DP# 272976, G. Kramer and G. Reddy, 5/31/2001) has
determined that the residues of concern, for the purpose of tolerance
expression, are diflubenzuron and its metabolites PCA and CPU.  The
proposed tolerance expression, listed in Section F of the petitions
discussed herein, is in agreement with HED MARC’s determination.

Tolerances for residues of diflubenzuron are established under 40 CFR
§180.377.  Tolerances listed in 40 CFR §180.377(a)(1) are expressed in
terms of diflubenzuron per se whereas tolerances listed under in 40 CFR
§180.377(a)(2) and 40 CFR §180.377(b) are expressed in terms of the
combined residues of diflubenzuron and its metabolites CPU and PCA.  

A summary of tolerance reassessment is presented in Table 12.  The
recommended tolerances for all commodities except barley grain, wheat
grain, and peanut nutmeat were derived with the aid of HED’s tolerance
spreadsheet.  The tolerance spreadsheet was not used for the
above-listed commodities because residues in/on treated samples were
mostly below the respective LOQs.  The recommended tolerances for the
commodities of small grains are contingent upon the requested label
revisions to specify appropriate PHIs.

Codex Harmonization

  SEQ CHAPTER \h \r 1 The Codex Alimentarius has established maximum
residue limits (MRL), expressed in terms of diflubenzuron per se, for
many commodities including:  apple (5 ppm), citrus fruits (0.5 ppm),
edible offal (mammalian) (0.1 ppm), eggs (0.05 ppm), meat (from mammals
other than marine mammals) (0.1 ppm), milks (0.02 ppm), mushrooms (0.3
ppm), pear (5 ppm), pome fruits (5 ppm), poultry meat (0.05 ppm), rice
(0.01 ppm), and rice straw and fodder (dry) 0.7 ppm).  As the U.S.
residue definition includes CPU and PCA, compatibility is not possible
with the proposed tolerances.  A copy of the International Residue Limit
Status (IRLS) sheet is attached to this memorandum.

Table 12.  Tolerance Summary for Diflubenzuron.

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

[Correct Commodity Definition]

Tolerances Proposed in PP#5E6965

Barley, grain	0.06	0.06

	Barley, forage	5.0	Delete	Not a RAC of barley as per Table 1 of OPPTS
860.1000.

Barley, hay	2.0	3.0

	Barley, straw	2.0	1.8

	Oat, grain	0.06	0.06	The available data for wheat may be translated to
oat; the corresponding tolerances recommended for wheat commodities also
apply to oat commodities.

Oat, forage	5.0	7.0

	Oat, hay	2.0	6.0

	Oat, straw	2.0	3.5

	Wheat, grain	0.06	0.06

	Wheat, forage	5.0	7.0

	Wheat, hay 	2.0	6.0

	Wheat, straw	2.0	3.5

	Grain, aspirated fractions	3.0	11	The maximum diflubenzuron residues of
concern expected in wheat aspirated grain fractions is 6.42 ppm which is
derived by multiplying the HAFT residue (<0.06 ppm; see Table 7) with
the processing factor (180x).

Pummelo	0.5 	0.50	The available data for citrus fruits may be translated
to pummelo.

Tolerances Proposed in PP#5E6966

Brassica, leafy greens, subgroup 5B	8.0	9.0

	Turnip greens	8.0	9.0

	Eggplant	1.0	Delete	Residue data for eggplant are required to determine
appropriate tolerance.

Okra	1.0	Delete	Residue data for okra are required to determine
appropriate tolerance.

Tolerances Proposed in PP#5E6967

Peanut	0.2	0.10

	Peanut, hay	20.0	55

	Peanut, refined oil	0.2	0.20	Peanut, oil 

A new peanut processing study is requested.



References

  SEQ CHAPTER \h \r 1 DP#:		261060

Subject:	  SEQ CHAPTER \h \r 1 PP# 8F4925.  Diflubenzuron (Dimilin® 2L,
EPA Reg #400-461) on Rice.  Results of Petition Method Validation (PMV).
 Case 289260.  Submission S571149.

From:		G. Kramer

To:		R. Kumar and M. Laws

Dated:		9/6/2002

MRID(s):	443993-03 & -06

  SEQ CHAPTER \h \r 1 DP#:		272976

Subject:	  SEQ CHAPTER \h \r 1 Health Effects Division (HED) Metabolism
Assessment Review Committee (MARC) Meetings of 2/20/01 & 5/8/01. 
Diflubenzuron.  Residues of Concern for Cancer Risk Assessment. 
Chemical 108201.

From:		G. Kramer and G. Reddy

To:		Y. Donovan

Dated:		5/31/2001

MRID(s):	None

  SEQ CHAPTER \h \r 1 DP#:		272978

™ 2L, EPA Reg #400-461) in/on Pears.  Evaluation of Residue Data and
Analytical Methods.

From:		G. Kramer

To:		S. Brothers and R. Forrest

Dated:		4/3/2001

MRID(s):	451196-01 and -02

  SEQ CHAPTER \h \r 1 DP#:		254273

Subject:	Submission of   SEQ CHAPTER \h \r 1 Multiresidue Method (MRM)
test information for updating PAM-I, Appendix II:

From:		J. Rowell

To:		B. McMahon

Dated:		3/22/199

MRID(s):	44707401

  SEQ CHAPTER \h \r 1 DP#:		254275

Subject:	  SEQ CHAPTER \h \r 1 PP# 8F4925.  Multiresidue Method Testing
of p-Chloroaniline and 4-Chlorophenylurea in Rice Grain and Soybeans.

From:		J. Rowell

To:		F. Griffith

Dated:		3/22/1999

MRID(s):	44707401

DP#s:		  SEQ CHAPTER \h \r 1 253043, 253041, 244487, 251221 and 251609

Subject:	  SEQ CHAPTER \h \r 1 PP#8F4925.  Diflubenzuron (Dimilin® 2L,
EPA Reg #400-461) on Rice.

Amendments of 8/19/98, 11/20/98, 12/3/98, 1/21/99, 1/27/99 & 2/3/99.

Analytical Method for Metabolites, Revised Label, Additional Residue,
Storage 

Stability and Rotational Crop Data.

From:		G. Kramer

To:		M. Johnson/A. Sibold

Dated:		2/17/1999

MRIDs	44577601, 44689701-02, 44699201, 44692701, 44692703, 4469500102,
and 44707401

  SEQ CHAPTER \h \r 1 DP#:		240107

Subject:	  SEQ CHAPTER \h \r 1 PP#8F4925.  Diflubenzuron (Dimilin® 2L,
EPA Reg #400-461) on Rice.  Evaluation of Residue Data and Analytical
Methods.

From:		G. Kramer

To:		T. Levine

Dated:		6/23/1998

MRID(s):	44486401, 44399301 thru 44399306

  SEQ CHAPTER \h \r 1 DP#:		209032

Subject:	  SEQ CHAPTER \h \r 1 Chemistry Chapters of the Reregistration
Eligibility Document

From:		S. Knizner

To:		S. Jennings, K, Whitby, and L. Kutney

Dated:		3/15/1995

MRID(s):	None

  SEQ CHAPTER \h \r 1 DP#s:		205481

Subject:	  SEQ CHAPTER \h \r 1 Diflubenzuron.  Confined Rotational Crop
Study.

From:		S. Knizner

To:		S. Jennings

Dated:		2/1/1995

MRID(s):	43274101

  SEQ CHAPTER \h \r 1 Attachments:

IRLS sheet

Appendix I - Tolerance Assessment Calculations

cc: G. Kramer (RAB1)

RDI: P.V. Shah (8/30/06); RAB1 Chemists (8/30/06)

G.F. Kramer:S10781:PY-S:(703)305-5079:7509P:RAB1

Template Version September 2005



INTERNATIONAL RESIDUE LIMIT STATUS

Chemical Name: N-[[(4-chlorophenyl)
amino]carbonyl]-2,6-difluorobenzamide	Common Name:  Diflubenzuron

	X Proposed tolerance

X Reevaluated tolerance

 Other	Date:  06/23/2006

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

 No Codex proposal step 6 or above

 No Codex proposal step 6 or above for the crops requested	Petition
Number:  PP#5E6965, PP#5E6966, and PP#5E6967

DP#s:  321623, 321625, and 321627

Residue definition (step 8/CXL):  Diflubenzuron per se	Reviewer/Branch:
RAB1

	Residue definition:  Combined residues of diflubenzuron and its
metabolites PCA and CPU

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

Apple  	5	Barley, grain	0.06

Citrus fruits  	0.5	Oat, grain	0.06

Edible offal (mammalian)  	0.1	Wheat, grain	0.06

Eggs  	0.05	Barley, forage	5.0

Meat (from mammals other than marine mammals)  	0.1	Oat, forage	5.0

Milks  	0.02	Wheat, forage	5.0

Mushrooms  	0.3	Barley, hay	2.0

Pear  	5	Oat, hay	2.0

Pome fruits  	5	Wheat, hay	2.0

Poultry meat  	0.05	Barley, straw	2.0

Rice  	0.01	Oat, straw	2.0

Rice straw and fodder, Dry 	0.7	Wheat, straw	2.0



Grain, aspirated fractions	3



Pummelo	0.5



Peanut	0.2



Peanut, hay	20



Peanut, refined oil 	0.2



Brassica, leafy greens, (subgroup5B)	8.0



Turnip greens	8.0



Eggplant	1.0



Okra	1.0

Limits for Canada	Limits for Mexico

X No Limits

 No Limits for the crops requested	  No Limits

  No Limits for the crops requested

Residue definition:	Residue definition:

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

Rev. 1998

APPENDIX  I.  Tolerance Assessment Calculations.

The Agency’s Guidance for Setting Pesticide Tolerances Based on Field
Trial Data was utilized for determining appropriate tolerance levels
for:  mustard greens, peanut hay, barley hay, barley straw, wheat
forage, wheat hay, and wheat straw.  The combined residue levels of
diflubenzuron in these commodities were readily quantifiable, and in
each case, <10% of the residue values were below the LOQ.  Residue data
for peanut nutmeat, barley grain, and wheat grain were not entered into
the spreadsheet because >15% of residue values were below the LOQ.

The dataset used to establish a tolerance for combined diflubenzuron
residues on mustard greens consisted of field trial data representing
application rates of 0.19-0.26 lb ai/A (3 or 4 applications at
0.061-0.066 lb ai/A/application) with a 6- to 8-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 residues values used to calculate the tolerance are provided in
Table I-1.

The dataset used to establish a tolerance for combined diflubenzuron
residues on peanut hay consisted of field trial data representing
application rates of 0.373-0.385 lb ai/A (3 applications at 0.121-0.132
lb ai/A/application) with a 20- to 28-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
residues values used to calculate the tolerance are provided in Table
I-2.

The dataset used to establish tolerances for combined diflubenzuron
residues on barley hay and straw consisted of field trial data
representing application rates of 0.0592-0.0629 lb ai/A with a 15- to
39-day PHI for hay and a 50- to 76-day PHI for straw.  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
residues values used to calculate the tolerances are provided in Table
I-3.

The dataset used to establish tolerances for combined diflubenzuron
residues on wheat forage, hay, and straw consisted of field trial data
representing application rates of 0.0619-0.0642 lb ai/A with a 3- to
12-day PHI for forage, a 28- to 32-day PHI for hay, and a 56- to 62-day
PHI for straw.  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 residues values used to calculate
the tolerances are provided in Table I-4.

For peanut hay, barley hay, barley straw, wheat forage, wheat hay, and
wheat straw, visual inspection of the lognormal probability plots
(Figures 3, 5, 7, 9, 11, and 13) indicates that the datasets are
reasonably lognormal, and the result from the approximate
Shapiro-Francia test statistic (Figures 4, 6, 8, 10, 12, and 14)
confirmed that the assumption of lognormality should not be rejected. 
For mustard greens, visual inspection of the lognormal probability plot
and the result from the approximate Shapiro-Francia test statistic
indicate that the dataset for mustard greens is not lognormal.

Since the field trial data for diflubenzuron on mustard greens are not
lognormal, the upper bound on the 89th percentile should be selected as
the tolerance value (distribution-free method).  Using the rounding
procedure as outlined in the Guidance for Setting Pesticide Tolerances
Based on Field Trial Data SOP, the upper bound on the 89th percentile
rounds to the value 9.0 ppm.  Therefore, 9.0 ppm is the recommended
tolerance level for diflubenzuron on mustard greens.

Since the field trial data for diflubenzuron on peanut hay represent a
small dataset (i.e., less than 15 samples) and are reasonably lognormal,
the upper bound estimate of the 95th percentile based on the median
residue value was compared to the minimum of the 95% upper confidence
limit (UCL) on the 95th percentile and the point estimate of the 99th
percentile, and the minimum value was selected as the tolerance value. 
Using the rounding procedure as outlined in the Guidance for Setting
Pesticide Tolerances Based on Field Trial Data SOP, 55 ppm is the
recommended tolerance level for diflubenzuron on peanut hay.

Since the field trial data for diflubenzuron on barley hay represent a
small dataset (i.e., less than 15 samples) and are reasonably lognormal,
the upper bound estimate of the 95th percentile based on the median
residue value was compared to the minimum of the 95% UCL on the 95th
percentile and the point estimate of the 99th percentile, and the
minimum value was selected as the tolerance value.  Using the rounding
procedure as outlined in the Guidance for Setting Pesticide Tolerances
Based on Field Trial Data SOP, 3.0 ppm is the recommended tolerance
level for diflubenzuron on barley hay.

Since the field trial data for diflubenzuron on barley straw represent a
small dataset (i.e., less than 15 samples) and are reasonably lognormal,
the upper bound estimate of the 95th percentile based on the median
residue value was compared to the minimum of the 95% UCL on the 95th
percentile and the point estimate of the 99th percentile, and the
minimum value was selected as the tolerance value.  Using the rounding
procedure as outlined in the Guidance for Setting Pesticide Tolerances
Based on Field Trial Data SOP, 1.8 ppm is the recommended tolerance
level for diflubenzuron on barley straw.

Since the field trial data for diflubenzuron on wheat forage represent a
small dataset (i.e., less than 15 samples) and are reasonably lognormal,
the upper bound estimate of the 95th percentile based on the median
residue value was compared to the minimum of the 95% UCL on the 95th
percentile and the point estimate of the 99th percentile, and the
minimum value was selected as the tolerance value.  Using the rounding
procedure as outlined in the Guidance for Setting Pesticide Tolerances
Based on Field Trial Data SOP, 7.0 ppm is the recommended tolerance
level for diflubenzuron on wheat forage.

Since the field trial data for diflubenzuron on wheat hay represent a
small dataset (i.e., less than 15 samples) and are reasonably lognormal,
the upper bound estimate of the 95th percentile based on the median
residue value was compared to the minimum of the 95% UCL on the 95th
percentile and the point estimate of the 99th percentile, and the
minimum value was selected as the tolerance value.  Using the rounding
procedure as outlined in the Guidance for Setting Pesticide Tolerances
Based on Field Trial Data SOP, 6.0 ppm is the recommended tolerance
level for diflubenzuron on wheat hay.

Since the field trial data for diflubenzuron on wheat straw represent a
small dataset (i.e., less than 15 samples) and are reasonably lognormal,
the upper bound estimate of the 95th percentile based on the median
residue value was compared to the minimum of the 95% UCL on the 95th
percentile and the point estimate of the 99th percentile, and the
minimum value was selected as the tolerance value.  Using the rounding
procedure as outlined in the Guidance for Setting Pesticide Tolerances
Based on Field Trial Data SOP, 3.5 ppm is the recommended tolerance
level for diflubenzuron on wheat straw.

Table I-1.	Residue data used to calculate tolerance for diflubenzuron on
mustard greens.

Regulator:	  EPA

Chemical:	  Diflubenzuron

Crop:	  Mustard greens

PHI:	  6-8 Days

App. Rate:	  0.190-0.256 lb ai/A

Submitter:	  IR-4

MRID Citation:	  MRID 46609601

	Combined Residues of Diflubenzuron (ppm)

	1.04

	1.18

	0.84

	2.21

	1.97

	3.09

	1.10

	0.93

	<0.065

	<0.065

	1.19

	1.26

	1.28

	2.91

	7.07

	6.62



Figure   SEQ Figure \* ARABIC  1 :  Lognormal Probability Plot of
Combined Diflubenzuron Residues in Mustard Greens.

Figure   SEQ Figure \* ARABIC  2 :  Data summary table for combined
residues of diflubenzuron in mustard greens.

Table I-2.	Residue data used to calculate tolerance for diflubenzuron on
peanut hay.

Regulator:	  EPA

Chemical:	  Diflubenzuron

Crop:	  Peanut hay

PHI:	  20-28 Days

App. Rate:	  0.373-0.385 lb ai/A

Submitter:	  IR-4

MRID Citation:	  MRID 46609401

	Combined Residues of Diflubenzuron (ppm)

	18.46

	10.79

	17.04

	8.42

	7.90

	2.70

	1.12

	1.18

	1.67

	7.17

	2.05



Figure   SEQ Figure \* ARABIC  3 :  Lognormal probability plot for
combined residues of diflubenzuron in peanut hay.

 

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-Data summary table for residues of diflubenzuron in peanut hay.

Table I-3.	Residue data used to calculate tolerance for diflubenzuron on
barley.

Regulator:	EPA

Chemical:	Diflubenzuron

Crop:	Barley Hay	Barley Straw

PHI:	15-39 days	50-76 days

App. Rate:	0.0592-0.0629 lb ai/A

Submitter:	IR-4

MRID Citation:	MRID 46609501

	Combined Residues of Diflubenzuron (ppm)	Combined Residues of
Diflubenzuron (ppm)

	0.74	0.23

	0.76	0.15

	0.47	0.11

	0.82	0.14

	0.28	0.31

	0.70	0.32

	0.54	0.45

	0.66	0.48

	0.56	0.58

	0.73	0.56

	0.13	<0.06

	0.13	<0.06

	1.33	0.55

	1.47	0.56



Figure   SEQ Figure \* ARABIC  5 :  Lognormal probability plot of
combined diflubenzuron residues in barley hay

Figure   SEQ Figure \* ARABIC  6 :  Data summary table for combined
residues of diflubenzuron in barley hay.

Figure   SEQ Figure \* ARABIC  7 : Lognormal probability plot for
combined residues of diflubenzuron in barley straw.

Figure   SEQ Figure \* ARABIC  8 : Data summary table for combined
residues of diflubenzuron in barley straw.

Table I-3.	Residue data used to calculate tolerance for diflubenzuron on
wheat.

Regulator:	EPA

Chemical:	Diflubenzuron

Crop:	Wheat Forage	Wheat Hay	Wheat Straw

PHI:	3-12 days	28-32 days	50-76 days

App. Rate:	0.0619-0.0642 lb ai/A

Submitter:	IR-4

MRID Citation:	MRID 46609501

	1.17	0.90	0.24

	2.49	0.87	0.35

	2.65	1.25	0.78

	2.30	1.31	1.04

	3.97	0.26	<0.06

	3.62	0.11	0.08



Figure   SEQ Figure \* ARABIC  9 :  Lognormal probability plot for
combined residues of diflubenzuron in wheat forage.

Figure   SEQ Figure \* ARABIC  10 :  Summary data for combined residues
of diflubenzuron in wheat forage.

Figure   SEQ Figure \* ARABIC  11 :  Lognormal probability plot of
combined residues of diflubenzuron in wheat hay.

Figure   SEQ Figure \* ARABIC  12 :  Summary data of combined residues
of diflubenzuron in wheat hay.

Figure   SEQ Figure \* ARABIC  13 :  Lognormal probability plot of
combined residues of diflubenzuron in wheat straw.

Figure   SEQ Figure \* ARABIC  14 :  Data summary for combined residues
of diflubenzuron in wheat straw.

Diflubenzuron	Summary of Analytical Chemistry and Residue Data	DP#
321623

 PAGE   

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Diflubenzuron	Summary of Analytical Chemistry and Residue Data	DP#
321623

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