Document ID: EPA-HQ-OPP-2006-0181-0009
Agency: epa
Document Type: Supporting & Related Material
Title: 
Posted Date: 2006-11-29T05:00Z

SEQ CHAPTER \h \r 1 Primary Evaluator

Date:  14-SEP-2006

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

Registration Action Branch (RAB1)

Health Effects Division (HED) (7509C)

	Approved by

Date:  14-SEP-2006

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

RAB1/HED (7509C)

	

  SEQ CHAPTER \h \r 1 This DER was originally prepared under contract by
Dynamac Corporation (1910 Sedwick Rd., Building 100, Durham, NC 27713;
submitted 06/23/2006).  The DER has been reviewed by HED and revised to
reflect current Office of Pesticide Programs (OPP) policies.

STUDY REPORT:

46609501.  Corley, J. (2005) Diflubenzuron:  Magnitude of the Residue on
Small Grain.  Lab Project Number:  08024.02-PTR01.  Unpublished study
prepared by Interregional Research Project No. 4 (IR-4).  800 p.

EXECUTIVE SUMMARY:

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 flowable concentrate (FlC)) was
applied once to barley and wheat fields as a broadcast foliar
application at 0.0592-0.0642 lb ai/A 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, 4-chlorophenylurea (CPU), and 4-chloroaniline (PCA)
using high-performance liquid chromatography (HPLC)/ultraviolet (UV),
gas chromatography/mass spectroscopy (GC/MS), and GC/MS with
selected-ion monitoring (SIM), respectively.  These methods, which are
similar or based on method submissions previously deemed acceptable by
the Agency, were adequately validated in conjunction with the field
sample analyses.  The lowest limit of method validations (LLMVs) are
0.05 ppm for diflubenzuron and 0.005 ppm for CPU and PCA.

The results of the field trials 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.

STUDY/WAIVER ACCEPTABILITY/DEFICIENCIES/CLARIFICATIONS:

Under the conditions and parameters used in the study, the submitted
residue data for barley and wheat commodities are scientifically
acceptable.  The acceptability of this study for regulatory purposes
including the adequacy of the number and location of field trials will
be addressed in the forthcoming U.S. EPA Residue Chemistry Summary
Document DP# 321623.

COMPLIANCE:

Signed and dated Good Laboratory Practice (GLP), Quality Assurance and
Data Confidentiality statements were provided.  No deviations were
reported that would substantially impact the validity of the study.

A.	BACKGROUND INFORMATION

Diflubenzuron 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.  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 Reregistration
Eligibility Decision (RED) for diflubenzuron was issued in August, 1997
(EPA 738-R-97-008).  Tolerances for residues of diflubenzuron are
established under 40 CFR §180.377.

TABLE A.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 Product (EP)	2 lb/gal FlC formulation; DIMILIN® 2L (EPA Reg.
No. 400-461)

Regulated Metabolite	

Common name	4-chlorophenylurea (CPU)

Regulated Metabolite	

Common name	4-chloroaniline (PCA)

TABLE A.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

	

B.	EXPERIMENTAL DESIGN

B.1.	Study Site Information

Barley and wheat were grown and maintained at each trial site (Table
B.1.1) using typical agricultural practices for the respective
geographical region.  Information pertaining to soil conditions,
temperature, and precipitation as well as irrigation for all sites was
provided.  Weather conditions were within normal variations for the
region.  Information was also provided on maintenance chemicals and
other pesticides used at each site.

TABLE B.1.1.	Trial Site Conditions.

Trial Identification

(City, State; Year)	Soil characteristics1

	Type	%OM	pH	CEC (meq/g)

Fort Collins, CO; 2003	Sandy Loam	1.7	8.1	28.1

Kimberly, ID; 2002	Clay	1.6	8.2	NR

Aberdeen, ID; 2002	Loamy Sand	1.3	7.5	NR

Kimberly, ID; 2002	Silt Loam	1.65	8.2	NR

Minot, ND; 2003	Loam	3.4	4.7	NR

Fargo, ND; 2003	Silty Clay	5.2	7.4	NR

Minot, ND; 2003	Loam	3.4	4.7	NR

Fargo, ND; 2003	Silty Clay	5.2	7.4	NR

Minot ND; 2003	Loam	3.8	6.0	NR

Velva, ND; 2003	Loam	3.9	6.2	20.7

Prosser, WA; 2002	Loam	1.1	6.3	12.8

1  OM = Organic matter, CEC = Cation-exchange capacity.  These
parameters are optional except in cases where their value affects the
use pattern for the chemical.

NR = Not Reported.

TABLE B.1.2.  Study Use Pattern on Barley and Wheat.

Location

City, State; Year

Trial ID	

EP1	Application	

Tank Mix/ Adjuvants

Method; Timing	Volume GPA	 Single Rate 

(lb ai/A)	RTI2

(days)	Total Rate

(lb ai/A)

	Barley Field Trials

Fort Collins, CO 2003; CO09	2 lb/gal FlC	One broadcast foliar
application; Pre-boot	12	0.0613	NA	0.0613	None

Kimberly, ID 2002;

ID12	2 lb/gal FlC	One broadcast foliar application;  pre-stem elongation
12	0.0592	NA	0.0592	None

Aberdeen, ID 2002;

ID13	2 lb/gal FlC	One broadcast foliar application;  Pre-boot	15	0.0620
NA	0.0620	None

Minot, ND 2003;

ND01	2 lb/gal FlC	One broadcast foliar application;  jointing	10	0.0629
NA	0.0629	None

Fargo, ND 2003;

ND02	2 lb/gal FlC	One broadcast foliar application;  5-6 leaves	12
0.0621	NA	0.0621	None

Minot, ND 2003;

ND03	2 lb/gal FlC	One broadcast foliar application; jointing	10	0.0619
NA	0.0619	None

Velva, ND 2003;

ND12	2 lb/gal FlC	One broadcast foliar application;  Feekes 8	20	0.0628
NA	0.0628	None

Wheat Field Trials

Kimberly, ID 2002;

ID14	2 lb/gal FlC	One broadcast foliar application;  Pre-stem elongation
13	0.0642	NA	0.0642	None

	13	0.621	NA	0.621	None

Fargo, ND 2003;

ND04	2 lb/gal FlC	One broadcast foliar application; 5-6 leaves	12	0.0620
NA	0.0620	None

Minot ND 2003;

ND05	2 lb/gal FlC	One broadcast foliar application;  jointing	10	0.0619
NA	0.0619	None

1  EP = End-use Product; DIMILIN® 2L.

2  RTI = Retreatment Interval.

TABLE B.1.3.	Trial Numbers and Geographical Locations.

NAFTA Growing Zones 1	Submitted	Requested 2

	Barley	Wheat	Barley	Wheat

1	---	---	1 3	---

2	---	---	1 3	1

3	---	---	---	---

4	---	---	---	1

5	1	1	3	5

6	---	---	---	1

7	3	1	4	5

8	1	---	---	6

9	---	---	1	---

10	---	---	1	---

11	2	1	2	1

12	---	---	---	---

Total	7	3	12	20

1   Zones 13-21 and 1A, 5A, 5B, and 7A were not included as the proposed
use is for the US only.

2  Suggested distribution of field trials when individual tolerances are
sought for barley and wheat commodities (Source:  Table 5 of OPPTS
860.1500.

3  Either region/zone is acceptable.

B.2.	Sample Handling and Preparation

Single control and duplicate treated samples of barley hay, grain, and
straw and wheat forage, hay, grain, and straw (amount not reported) were
harvested from each trial site at appropriate stages for the commodity: 
barley hay 15-39 DAT, barley grain and straw 50-76 DAT, wheat forage
3-12 DAT, wheat hay 28-32 DAT, and wheat grain and straw 56-76 DAT.  All
samples were placed in frozen storage within 0.25-2.5 hours of
collection.  Field storage time was not documented.  Samples were
shipped frozen by ACDS freezer truck to the analytical laboratory (PTRL
West, Hercules, CA) where samples were stored frozen at <0 °C until
residue analysis.

B.3.	Analytical Methodology

The collected samples were analyzed for diflubenzuron, CPU, and PCA
using a separate PTRL method for each analyte.  The methods are
described in “Dimilin 25W, Dimilin 80WG, and Dimilin 2L in Almonds: 
Magnitude of Residue Study, J. Rose dated September 1999."

For analysis of diflubenzuron, samples are extracted twice with
acetonitrile (ACN) (three times for wheat straw) and centrifuged.  The
supernatants are combined and partitioned with hexane.  The ACN layer is
concentrated to dryness, redissolved in ACN and water, and sequentially
cleaned up on a C18 solid-phase extraction (SPE) column and silica-gel
SPE column.  After clean up, residues are analyzed by HPLC on a C8 or
C18 column with UV detection.  The limit of detection (LOD) for the
diflubenzuron method for barley grain was calculated to be 0.027 ppm and
the limit of quantitation (LOQ) was calculated to be 0.081 ppm.  The
diflubenzuron LODs for wheat grain and bran were calculated to be 0.012
ppm and 0.023 ppm, respectively, and the LOQs were 0.037 ppm and 0.070
ppm, respectively.  The LLMV for diflubenzuron was 0.05 ppm for each
commodity.

For analysis of CPU, samples are dried with sodium sulfate and extracted
with ethyl acetate.  Residues are evaporated to dryness, redissolved in
acetone and petroleum ether and cleaned up on a silica-gel SPE column. 
Again, residues are evaporated to dryness and redissolved in
acetonitrile.  The sample is filtered and derivatized in a glass tube
with heptafluorobutyric anhydride for 10 minutes.  Residues are then
analyzed by GC/MS.  The LODs for the CPU method for barley grain and hay
were calculated to be 0.001 ppm and 0.002 ppm, respectively, and the
LOQs were calculated to be 0.004 ppm and 0.006 ppm, respectively.  For
wheat grain, the LOD for CPU was calculated to be 0.002 ppm and the LOQ
was 0.006 ppm.  The LLMV for CPU was 0.005 ppm for each commodity.

For analysis of PCA, residues are acidified with HCl and sonicated for
30 minutes at 60 °C.  NaOH and NaCl are added, and residues are
extracted three times with hexane.  Residues are then partitioned with
0.1 N HCl, neutralized, and extracted with hexane.  Extracts are dried
and cleaned up with a Florisil column, derivatized with
heptafluorobutyric acid for 10 minutes, after which water, sodium
carbonate and hexane are added.  Residues in the hexane layer are
analyzed by GC/MS with SIM.  The LODs for the PCA method for barley
grain and straw were each calculated to be 0.001 ppm, and the LOQs were
each calculated to be 0.003 ppm.  The LOD for the PCA method in each
wheat matrices was calculated to be 0.001 ppm and the LOQ was 0.001 ppm
for wheat grain, 0.002 ppm for wheat hay, 0.003 ppm for barley hay,
grain, and straw, wheat grain and straw, and wheat flour and germ, and
0.004 ppm for wheat bran.  The LLMV for PCA was 0.005 ppm for each
commodity.

In conjunction with the analysis of field trial samples, the above
methods were validated using control samples of barley and wheat
matrices fortified with diflubenzuron, CPU or PCA at 0.005-1.0 ppm.

C.	RESULTS AND DISCUSSION

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, a single application of diflubenzuron (2 lb/gal FlC) was made
to barley and wheat fields as a broadcast foliar application at
0.0592-0.0642 lb ai/A 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 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; a few recoveries were outside of this
range but should not impact the validity of the method.  Adequate
examples calculation and samples chromatograms were provided.

Grain, straw, forage and hay samples were stored frozen for up to 189,
232, 262, and 245 days, respectively, prior to residue analysis (Table
C.2.1).  A freezer storage stability study was conducted to validate
sample storage conditions and intervals.  The results of this study
(Table C.2.2) 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.

The results 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 samples were mostly
below the LLMV of 0.005 ppm.

The results of the field trials are presented in Tables C.3 and C.4. 
Following a single foliar application of the 2 lb/gal FlC formulation to
the test crops, the combined residues of diflubenzuron and its CPU and
PCA metabolites 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 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.

Common cultural practices were used to maintain the test crops.  The
weather conditions and the maintenance chemicals and fertilizer used in
the study did not have a notable impact on the residue data.

TABLE C.1.	Summary of Concurrent and Method Recoveries of Diflubenzuron
from Small Grains.

Analyte	

Matrix	Spike Level

(ppm)	

Sample Size (n)	

Recoveries (%)	Mean ± Std Dev

(%)

Concurrent

Diflubenzuron	Grain

(barley and wheat)	0.05-0.10	16	62, 86, 94, 95, 96, 100, 100, 106, 106,
108, 108, 108, 109, 114, 116, 116	102 ( 14

CPU

0.005	14	60, 60, 60, 60, 60, 60, 80, 80, 80, 80, 80, 100, 100, 100	76 (
16

PCA

0.005	14	86, 94, 102, 104, 104, 106, 106, 106, 106, 108, 108, 110, 112,
120	105 ( 8

Diflubenzuron	Hay

(barley and wheat)	0.1-1.0	12	66, 68, 71, 79, 80, 84, 87, 88, 107, 111,
120, 129 	91 ( 21

CPU

0.005-0.10	12	75, 84, 89, 100, 100, 100, 100, 101, 101, 109, 109, 119	99
( 12

PCA

0.005	10	98, 100, 102, 104, 106, 106, 112, 114, 114, 118	107 ( 7

Diflubenzuron	Straw

(barley and wheat)	0.05-0.20	12	62, 71, 76, 77, 81, 82, 84, 88, 90, 90,
93, 109	84 ( 12

CPU

0.10	12	60, 60, 60, 80, 80, 90, 90, 90, 110, 120, 120, 120	90 ( 23

PCA

0.005	12	96, 98, 102, 104, 104, 104, 108, 108, 110, 110, 112, 116	106 (
6

Diflubenzuron	Forage

(wheat)	0.05-1.0	4	84, 98, 102, 116	100 ( 13

CPU

0.1	4	81, 84, 109, 112	97 ( 16

PCA

0.005	4	98, 100, 106, 112	104 ( 6

Method Validation

Diflubenzuron	Grain

(barley and wheat)	0.05-0.5	6	87, 94, 94, 96, 98, 101	95 ( 5

CPU

0.005-0.05	6	58, 72, 80, 80, 100, 120	85 ( 22

PCA

0.005-0.10	9	112, 112, 112, 114, 116, 116, 117, 117, 119	115 ( 3

Diflubenzuron	Hay

(barley and wheat)	0.05-0.5	6	82, 84, 86, 91, 94, 112	92 ( 11

CPU

0.005-0.05	6	80, 80, 80, 92, 96, 98	88 ( 9

PCA

0.005-0.05	6	104, 106, 106, 108, 108, 110	107 ( 2

Diflubenzuron	Straw

(barley and wheat)	0.05-0.50	6	78, 78, 80, 81, 91, 104	85 ( 10

CPU

0.005-0.05	6	80, 80, 80, 88, 88, 90	84 ( 5

PCA

0.005-0.05	6	94, 97, 98, 103, 103, 111	101 ( 6

TABLE C.2.1	Summary of Storage Conditions.

Matrix 	Storage Temperature (°C)	Actual Storage Duration1

(days)	Interval of Demonstrated Storage Stability

(days)

Grain	<0	169-189	293-348

Straw

166-232	299-302

Forage

183-262	267-422

Hay

205-245	251-359

1  From harvest to extraction for analysis.  Extracts were stored for up
to 5 days before analysis



TABLE C.2.2	Stability of Diflubenzuron and its Metabolites in Frozen
Barley and Wheat Matrices.

Matrix	

Analyte	

Spike Level

(ppm)	Storage Interval 

(Days)	Freshly Fortified Recoveries (%)

[Average]	Stored Sample Recoveries (%)

[Average]	Average Corrected Stored Recovery (%)1

Barley grain	Diflubenzuron	0.5	0	108, 106 [107]	--	--

	182	96, 99 [98]	92, 79 [86]	88

	296	86, 86 [86]	93, 88 [91]	105

	CPU

0	80, 100 [90]	--	--

	195	67, 71 [69]	46, 60 [53]	77

	348	80, 80 [80]	59, 77 [68]	85

	PCA

0	108, 106 [107]	--	--

	118	85, 89 [87]	32, 50 [41]	47

	293	106, 102 [104]	31, 35 [33]	33

Barley straw	Diflubenzuron	0.5	0	84, 76 [80]	--	--

	134	72, 74 [73]	73, 79 [76]	104

	301	81, 61 [71]	83, 84 [84]	118

	CPU

0	120, 120 [120]	--	--

	233	77, 104 [91]	40, 67 [54]	59

	299	60, 90 [75]	14, 37 [26]	34

	PCA

0	108, 110 [109]	--	--

	168	104, 108 [106]	88, 87 [88]	88

	302	102, 108 [105]	88, 91 [90]	90

Wheat forage	Diflubenzuron	0.5	0	98, 84 [91]	--	--

	245	84, 99 [92]	72, 81 [77]	83

	422	71, 64 [68]	54, 67 [61]	89

	CPU

0	81, 84 [83]	--	--

	267	105, 101 [103]	90, 78 [84]	84

	PCA

0	98, 100 [99]	--	--

	194	104, 109 [107]	50, 56 [53]	53

	345	100, 100 [100]	38, 40 [39]	39

Wheat hay	Diflubenzuron	0.5	0	107, 111 [109]	--	--

	140	85, 86 [86]	90, 85 [88]	102

	337	80, 71 [76]	80, 77 [79]	103

	CPU

0	100, 101 [101]	--	--

	251	80, 85 [83]	51, 57 [54]	65

	355	80, 80 [80]	21, 27 [24]	30

	PCA

0	102, 106 [104]	--	--

	212	104, 107 [106]	67, 70 [69]	69

	359	110, 104 [107]	75, 77 [76]	76

1  Average corrected recoveries were reported by the petitioner.



TABLE C.3.	Residue Data from Barley and Wheat Field Trials with
Diflubenzuron.

Trial ID

(City, State; Year) 	

Zone	

Crop; Variety	Total Rate

(lb ai/A)	

PHI (days)	

Matrix	

Residues (ppm)1

DFB	CPU	PCA	Combined

Kimberly, ID 2002

ID12	11	Barley; Eight Twelve (Winter)	0.0592	76	Grain	<0.05, <0.05
<0.005, <0.005	<0.005, <0.005	<0.06, <0.06

27	Hay	0.73, 0.75	0.006, 0.005	<0.005, <0.005	0.74, 0.76

76	Straw	0.22, 0.14	<0.005, <0.005	<0.005, <0.005	0.23, 0.15

Aberdeen, ID 2002

ID13	11	Barley;Gallatin (Winter)	0.0620	71	Grain	<0.05, <0.05	<0.005,
<0.005	<0.005, <0.005	<0.06, <0.06

29	Hay	0.46, 0.81	0.011, 0.012	<0.005, <0.005	0.47, 0.82

71	Straw	0.10, 0.13	<0.005, <0.005	<0.005, <0.005	0.11, 0.14

Minot, ND 2003

ND01	7	Barley; Robust (Spring)	0.0629	55	Grain	<0.05, <0.05	<0.005,
<0.005	<0.005, <0.005	<0.06, <0.06

28	Hay	0.25, 0.66	0.024, 0.034	<0.005, <0.005	0.28, 0.70

55	Straw	0.30, 0.31	<0.005, <0.005	<0.005, <0.005	0.31, 0.32

Fargo, ND 2003

ND02	5	Barley;Robust (Spring)	0.0621	54	Grain	<0.05, <0.05	<0.005,
<0.005	<0.005, <0.005	<0.06, <0.06

31	Hay	0.52, 0.64	0.016, 0.015	<0.005, <0.005	0.54, 0.66

54	Straw	0.44, 0.47	<0.005, <0.005	<0.005, <0.005	0.45, 0.48

Minot, ND 2003

ND03	7	Barley;Robust (Spring)	0.0619	54	Grain	<0.05, <0.05	<0.005,
<0.005	<0.005, <0.005	<0.06, <0.06

25	Hay	0.52, 0.70	0.038, 0.025	<0.005, <0.005	0.56, 0.73

54	Straw	0.57, 0.55	<0.005, <0.005	<0.005, <0.005	0.58, 0.56

Fort Collins, CO 2003

CO09	8	Barley; Moravian 37 (Spring)	0.0613	75	Grain	<0.05, <0.05	<0.005,
<0.005	<0.005, <0.005	<0.06, <0.06

39	Hay	0.11, 0.11	0.018, 0.019	<0.005, <0.005	0.13, 0.13

75	Straw	<0.05, <0.05	<0.005, <0.005	<0.005, <0.005	<0.06, <0.06

Velva, ND 2003

ND12	7	Barley; Foster (Spring)	0.0628	50	Grain	<0.05, <0.05	<0.005,
<0.005	<0.005, <0.005	<0.06, <0.06

15	Hay	1.31, 1.44	0.022, 0.031	<0.005, <0.005	1.33, 1.47

50	Straw	0.54, 0.54	0.010, 0.013	<0.005, <0.005	0.55, 0.56

Kimberly, ID 2002

ID14	11	Wheat; Brundage (Winter)	0.0642	76	Grain	<0.05, <0.05	<0.005,
<0.005	<0.005, <0.005	<0.06, <0.06

32	Hay	0.89, 0.86	<0.005, <0.005	<0.005, <0.005	0.90, 0.87

76	Straw	0.23, 0.34	<0.005, <0.005	<0.005, <0.005	0.24, 0.35

12	Forage	1.16, 2.48	<0.005, <0.005	<0.005, <0.005	1.17, 2.49

	0.621	76	Grain	0.064, 0.053	<0.005, <0.005	<0.005, <0.005	0.065, 0.074

32	Hay	18.4, 11.6	0.022, 0.015	0.005, <0.005	18.4, 11.6

76	Straw	6.52, 6.03	0.007, 0.011	<0.005, <0.005	6.53, 6.04

12	Forage	11.7, 11.5	0.006, <0.005	<0.005, <0.005	11.7, 11.5

Fargo, ND 2003

ND04	5	Wheat; Oxen (Spring)	0.0620	56	Grain	<0.05, <0.05	<0.005, <0.005
<0.005, <0.005	<0.06, <0.06

31	Hay	1.24, 1.30	0.012, <0.005	<0.005, <0.005	1.25, 1.31

56	Straw	0.77, 1.03	0.008, 0.008	0.006, 0.006	0.78, 1.04

5	Forage	2.64, 2.29	<0.005, <0.005	<0.005, <0.005	2.65, 2.30

Minot ND 2003

ND05	7	Wheat; Mountrail (Spring)	0.0619	62	Grain	<0.05, <0.05	<0.005,
<0.005	<0.005, <0.005	<0.06, <0.06

28	Hay	0.25, 0.10	<0.005, <0.005	<0.005, <0.005	0.26, 0.11

62	Straw	<0.05, 0.07	<0.005, <0.005	<0.005, <0.005	<0.06, 0.08

3	Forage	3.96, 3.61	<0.005, <0.005	<0.005, <0.005	3.97, 3.62

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



TABLE C.4.	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. 

D.	CONCLUSION

The results of the field trials are adequate and will support use of the
2 lb/gal FlC formulation on barley and wheat for one foliar application
at a maximum seasonal rate of 0.0592-0.0642 lb ai/A.  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.

E.	REFERENCES

None.

F.	DOCUMENT TRACKING

RDI:  RAB1 Chemists (8/23/06)

Petition Number(s):  PP#5E6965

DP#:  321623

PC Code:  108201

Template Version June 2005

	Diflubenzuron/PC Code 108201/IR-4

	DACO 7.4.1/7.4.2/OPPTS 860.1500/OECD IIA 6.3.1, 6.3.2, 6.3.3 and IIIA
8.3.1, 8.3.2, 8.3.3

	Crop Field Trial – Small Grains – Barley and Wheat

PMRA Submission No.     /DP Barcode  D######     /MRID No.  

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