MRID 49103301 CDPR IMI Cotton (2011)

1 Reference

Beedle, E.; Harbin, A. (2011) Determination of Residues of Imidacloprid and its Metabolites 5

- Hydroxy

Imidacloprid and Imidacloprid Olefin in Bee Relevant Matrices Collected from Cotton, Grown at

Locations Treated with Imidacloprid at Least Once Per Year During Two Successive Years: Final Report.

Project Number: EBNTL056/01, M/404577/01/1. Unpublished study prepared by Bayer CropScience

and California Agricultural Research Inc . 149 p. MRID 49103301, CDPR Study ID 259129, Data Volume

51950

- 0785, Tracking ID# 246252

1. STUDY INFORMATION

Chemical: Imidacloprid PC Code 129099

Test Material: Provado 1.6F Percent Active

Ingredient: 17.4% A.I.

Study Type: Non

- Guideline field residue study on cotton to establish imidacloprid and

metabolite levels in nectar and leaves in site locations that have been previously

treated by chemigation for two successive years followed by a foliar spray

application.

Sponsor: Bayer CropScience

2T.W. Alexander Drive

Research Triangle Park, NC

USA 27709 Experiment Start and

End Date: August 13, 2010

– January 13, 2011

Sponsor Study

ID: EBNTL056

- 01

Study Locations: 5 Field Trials in Kern

and Kings County

located in California. Study

Completion

Date: March 31, 2011

GLP Status: Non

- GLP; No final protocol was submitted to CDPR for review and approval

. [CDPR study ID 254886 , Data Volume 51950

- 0758 , Tracking ID# 241026 ]

2. REVIEWER INFORMATION

Study Reviewed by:

California Department

of Pesticide Regulation Richard Bireley, Sr. Environmental Scientist (Specialist)

John Troiano, Ph.D., Research Scientist III

Alexander Kolosovich, Environmental Scientist

Brigitte Tafarella, Environmental Scientist

Denise Alder, Sr. Environmental Scientist (Specialist)

Russell Darling, Environmental Scientist

3. EXECUTIVE SUMMARY

Five trials were conducted in clay soils classified as ‘heavy’ to determine the residues of imidacloprid and

its metabolites (5

- hydroxy imidacloprid and imidacloprid olefin) in nectar and leaves collected from

cotton plants grown at locations treated with imidacloprid at least once per year for two years. All soils

had received previous application(s) of Admire Pro by chemigation at rates r anging from 0.18 to 0.38 lb.

a.i./acre in the prior year(s) and received one aerial foliar spray application of imidacl oprid (Provado 1.6

F, 17.4% imidacloprid by weight) in 2010 during flowering (BBCH61, beginning of flowering to BBCH67,

flowering finished and majority of flowers faded).MRID 49103301 CDPR IMI Cotton (2011)

2 Composite samples of cotton nectar and cotton leaves were collected two to seven day s prior to the

2010 imidacloprid application (pre

- application) and six days following the 2010 application (post

application). Nectar and leaves were collected from the same cotton plants.

The residues of imidacloprid, 5

- hydroxy imidacloprid, and imidacl oprid olefin were quantitated by high

performance liquid chromatography/triple stage quadrupole mass spectrometry (LC/MS/MS) using stable

isotopically labeled internal standards.

4. STUDY VALIDITY

Guideline Followed: Non

- guideline study ( final protocol was never reviewed CDPR)

Guideline Deviations: N/A

Other Deviations: N/A

Classification: Supplemental

Rationale: N/A

Reparability: N/A

5. MATERIALS AND METHODS

Test Material Characterization

Test item: Provado 1.6F Percent Active

Ingredient: 17.4% A.I.

Description: Flowable Concentrate Density: 1.41

- 1.54 g/mL

Material Source: Bayer Corporation Solubility: 0.51 to 0.61 g/L

CAS #: 138261

- 41

- 3 Expiration Date: 05/09/2012

5A. S TUDY D ESIGN

The field and sampling phases of this study were not conducted under GLP. The experimental start date

was August 13, 2010 (collection of the control nectar and leaves), and the experimental end date was

January 13, 2011 (last analysis). The field sampling phase of the study was conducted by California

Agricultural Research, Inc.

Data from five cotton trials conducted in "heavy" soils are presented in this report. All s ites were located

in either K ern County (sites 1, 2 and 3) or Kings County ( sites 4 and 5 ) of California . All had received

applications of imidacloprid in th e preceding year (2009); sites 1, 2, 3, and 5 also received imidacloprid

applications in 2008.

The analytical phase of this study was conducted under GLP and was initiated on December 3, 2010 (leaf

sample homogenization). Homogenization of the leaves and analysis of the all samples from this study

were performed at the Bayer Research Park (BRP) located in Stilwell, KS. Report preparation was

performed at BRP.

All raw data associated wi th this study are retained along with the protocol, protocol amendments and

the final report under Notebook Number EBNTL056

- 01 at locations specified by Bayer CropScience.MRID 49103301 CDPR IMI Cotton (2011)

3 5B. A PPLICATION T IMING AND R ATES

The cotton was grown in locations treated with one aerial application of imidacloprid in 2010 and at

least one chemigation application in preceding years. The 2010 aerial application rate of Provado 1.6F at

all five sites was 0.063 lb. a.i./acre (well below the m aximum label rate of 0.5 lb. a.i./acre )

. The

applications were made during flowering (BBCH61, beginning of flowering to BBCH67, flowering

finished, majority of flowers faded). All aerial applications of Provado 1.6F were made at approximately

10 GPA

. The test substance use pattern for imidacloprid in 2010 for each site is described in Table 1.

Table 1

. Study Use Pattern for 2010 Application of Provado 1.6 F on Cotton.*Trial IdentificationLocation (City, State, NAFTA,Region)End-Use Product(Formulation)Plot NameMethodTiming/Growth Stage (BBCH)Spray VolumeaRate lb a.i./A(oz Formulated Product/A)aInterval BetweenApplications (Days)bTotal Rate lb a.i./A(oz Formulated Product/A)

NT001 Heavy Soil,

Kern County,

CA, NAFTA

Region 10 Provado

1.6F Site 1

Buttonwillow

Clay, (Heavy) Aerial

Foliar BBCH

61

- 67

(Flowering) 10 0.063

(5.0) NA 0.063

(5.0)

NT002 Heavy Soil,

Kern County,

CA, NAFTA

Region 10 Provado

1.6F Site 2

Lokern Clay

(Heavy) Aerial

Foliar BBCH

61

- 67

(Flowering) 10 0.063

(5.0) NA 0.063

(5.0)

NT003 Heavy Soil,

Kern County,

CA, NAFTA

Region 10 Provado

1.6F Site 3

Lokern Clay

(Heavy) Aerial

Foliar BBCH

61

- 67

(Flowering) 10 0.063

(5.0) NA 0.063

(5.0)

NT004 Heavy Soil,

Kings

County, CA,

NAFTA

Region 10 Provado

1.6F Site 4

Houser Clay

(Heavy) Aerial

Foliar BBCH

61

- 67

(Flowering) 10 0.063

(5.0) NA 0.063

(5.0)

NT005 Heavy Soil,

Kings

County, CA,

NAFTA

Region 10 Provado

1.6F Site 5

Tulare Clay

(Heavy) Aerial

Foliar BBCH

61

- 67

(Flowering) 10 0.063

(5.0) NA 0.063

(5.0)

a Rates and spray volumes that were provided in the application order/recommendation. See Appendix 3 of the

study report in study report for field trial summary data.

b Interval between the first and second applications. NA = Not Applicable; only one applica tion occurred.

*Table 4 of the study reportMRID 49103301 CDPR IMI Cotton (2011)

4 Chemigation applications in previous years (2009 and/or 2008) ranged from 0.22 to 0.38 lb ai/acre /year.

Four of the five sites had chemigation applications in 2008 and 2009 ( trial NT001, NT002, NT003, NT005)

using the end product Admire Pro.

5C. S TUDY S ITE L OCATION AND C HARACTERISTICS

Three of the five trial sites were located in Kern County , California while the other two trial sites were

located in Kings County , California . The trial site conditions including soil characteristics can be found

below in Table 2. All five trial sites were conducted on clay soils classified as “heavy” and used

agronomic practices typical for commercial production of cotton. For a control group, untreated nectar

and leaf samples used for validation of the analytical method and for transit stability samples were

obtained from a nearby organic farm.

T emperature and precipitation data for each trial were obtained from th e nearest California Irrigation

Management Information System (CIMIS) weather station. Irrigation supplemented normal rainfall as

needed for all trials. Field report summaries for each trial detailing the site location, record of

imidacloprid use, maintenance chemicals, climat ic data, and irrigation data are located in Appendix 3 of

the study report

.

Table 2

. Trial Site Conditions for Imidacloprid on Cotton*

Trial Identification Trial Location

(County, State) Soil Type a Rainfall b (in) Temperature

Range b (°F)

NT001 Kern County, CA Buttonwillow Clay

(Heavy) 0.00 63

- 95

NT002 Kern County, CA Lokern Clay

(Heavy) 0.00 63

- 95

NT003

Kern County, CA Lokern Clay

(Heavy) 0.00 59

- 93

NT004

Kings County, CA Houser Clay

(Heavy) 0.00 59

- 93

NT005

Kings County, CA Tulare Clay

(Heavy) 0.00 64

- 96

a Classification of the soils was obtained from the Soil Survey Geographic (SSURGO) Database provided by the

Natural Resources Conservation Service. "Heavy" class represents soil with slow drainage capacity.

b Data is fo r the interval of the month of first application through the month of last sampling. Meteorological data

were obtained from nearby government weather stations.

*Table 3 of study report

5D. S AMPLE C OLLECTION

, H ANDLING

, P ROCESSING

At each sampling interval, quadruplicate samples of cotton nectar and leaves were collected from the

plot during flowering (BBCH 61, beginning of flowering to BBCH 67, flowering finished and majority of

flowers faded). Pre

- application samples were collecte d two to seven days prior to application and post

application samples were collected six days following application.MRID 49103301 CDPR IMI Cotton (2011)

5 Nectar and leaves were collected from the same plants, but by different individuals to prevent

contamination. The same number of treated l eaves was collected from each plant as necessary to

achieve a minimum sample weight of 500 g. Each leaf sample was a composite from high, low, inside,

and outside areas of the plant. Nectar was sampled from a minimum of twenty plants to obtain a

minimum sa mple weight of 1 g. The individual collecting nectar samples did not touch leaves or other

plant parts with their hands or any sampling equipment. All samples were protected from sunlight and

placed on either dry ice or blue ice in coolers during field col lection. All samples were placed in frozen

storage upon receipt at California Agricultural Research, Inc. Samples were shipped frozen via

Agricultural Chemicals Development Services (ACDS) and remained frozen until receipt at BRP.

Transit stability samples accompanied the field samples during all sample handling and preparation

steps to ensure the validity of the sampling practices.

Sample Storage

.

Upon arrival at BRP, all samples were immediately transferred to frozen storage. The leaf samples wer e homogenized with dry ice using a Robot Coupe chopper (Jackson, MS). The leaf samples were returned

to frozen storage immediately following homogenization, and all samples remained frozen at all times

except during subsampling for analysis. A summary of c ollection, shipment, and homogenization dates

for the trials is given in Appendix 2 of the study report

.

5E. A NALYTICAL M ETHODS

The analytical method used in this study measured the residues of imidacloprid, 5

- hydroxy imidacloprid,

and imidacloprid olefin in cotton nectar and leaves. 4

All neat analytical reference standards were stored frozen when not in use and all solutions, were stored

refrigerated or frozen. Analytical standard solutions used in this study were not stored for longer than

approxi mately 2 months and have been shown to be stable for this period of time. 5 All reference

standard solutions were prepared in parent imidacloprid equivalents and corrected for purity during

initial preparation.

For the determination of imidacloprid, 5

- hydr oxy imidacloprid (5

- 0H) and imidacloprid olefin (olefin) in

cotton nectar, an aliquot of the nectar was diluted with mobile phase [(9:1 v/v) water (H 2 0)/ methanol

(MeOH) containing 10 mM ammonium bicarbonate (NH 4 HC0 3 )] containing the stable, isotopically

labeled internal standards. The samples were analy zed, by high performance liquid

c hromatography/triple stage quadrupole mass spectrometry (LC/MS/MS).

For the determination of imidacloprid, 5

- 0H and olefin in cotton leaves, a ~0.50

- g aliquot of

homogenize d cotton leaves was extracted by vigorously shaking first with water; followed by

acetonitrile (ACN). The sample was amended with stable, isotopically labeled internal standards,

anhydrous magnesium sulfate (MgS0 4 ) and sodium chloride (NaCI). The sample wa s shaken vigorously

followed by centrifugation. The organic supernatant was decanted or transferred to a centrifuge tube

containing BONDESIL

- PSA (solid

- phase extraction sorbent primary and secondary amine) and MgS0 4 and

mixed, followed again by centrifugat ion. An aliquot of the supernatant was subjected to a C

- 18 SPE bond

elute cartridge and the eluate was evaporated. The solids were reconstituted with mobile phase. The

sample was filtered with a 0.45 um nylon syringe filter and analyzed by LC/MS/MS.MRID 49103301 CDPR IMI Cotton (2011)

6 Quant itation of each analyte was based on the daughter ion transitions of the analytes and the

respective internal standard analogs. The responses of LC/MS/MS system to each analyte and its

internal standard were measured in samples and in standards, and a rela tive response was calculated as

the ratio of the analyte and the stable isotopically labeled internal standard responses. The relative

response of the analyte in each sample was compared to the relative response of the analyte in the

standards (Appendix 4 in the study report ).

The relative responses of imidacloprid, 5

- hydroxy imidacloprid, and imidacloprid olefin in solvent were

measured over the range of 1 ppb to 2000 ppb for each analyte. The coefficients of determination (r 2 )

were calculated using linea r regression analysis (LCQUAN 2.5 TM, Microsoft Excel 2002).

The total imidacloprid residue is the sum of the individual measured residue values of imidacloprid, 5

- hydroxy imidacloprid, and imidacloprid olefin in parent equivalents. For the purpose of cal culating total

imidacloprid residues where individual analyte residue values were less than the limit of detection

(LOD), the residues were assigned a finite value of 1/2 the value of the respective LOD. This value is only

an estimate of potential residue in a sample, not a measured value.

The method for determining imidacloprid, 5

- hydroxy imidacloprid, and imidacloprid olefin residues

in/on cotton nectar and leaves was validated by measuring the recovery of these analytes from control

matrices fortified at their respective LOQs. Additional recoveries at higher fortification levels validated

the method for the highest residues observed in individual matrices. Concurrent recoveries of

imidacloprid, 5

- hydroxy imidacloprid, and Imidacloprid olefin were measur ed with each set of samples

to verify method performance.

5F. Q UALITY A SSURANCE R ESULTS

The responses of the LC/MS/MS system to imidacloprid, 5

- hydroxy imidacloprid, and imidacloprid olefin

were linear in solvent over the range of 1 ppb to 2000 ppb for each analyte. The coefficients of

determination were >0.993.

All control interferences for each analyte in cotton nectar and leaves were less than their respective

LODs.

The recovery data for imidacloprid, 5

- hydroxy imidacloprid, and imidacloprid o lefin re sidues are

summarized in Table 3 . All recoveries were corrected for any interference in corresponding controls. The

overall mean values of the recoveries for each matrix were within the acceptable range of 70% to 120%,

and the relative standard dev iation (RSD) values were below 20%. The analytical data summ aries are

located in Appendix 4 of the study report

.MRID 49103301 CDPR IMI Cotton (2011)

7 Table 3

. Summary of Recoveries of Imidacloprid from Cotton*

Crop Matrix Analyte a Spike Level

(ppm ) Sample

Size (n) Recoveries (%) b Mean %

Recovery Standard

%

DeviationCotton Leaves 5

- OH 0.002 7 107, 93, 93, 126, 88, 83, 105 99 15

0.010 1 95 95 NA

0.750 3 96, 106, 99 100 5

1.750 3 105, 103, 98 102 4

Imidacloprid 0.002 7 99, 95, 97, 108, 105, 101, 114 103 7

0.010 1 85 85 NA

0.750 3 90, 95, 86 90 5

1.750 3 97, 103, 89 97 7

Olefin 0.002 7 107, 109, 96, 113, 91, 96, 94 101 9

0.010 1 91 91 NA

0.750 3 95, 90, 98 94 4

1.750 3 94, 100, 86 93 7Cotton Nectar 5

- OH 0.001 7 92, 93, 96, 99, 69, 96, 82 90 10

0.050 3 101, 101, 101 101 0.3

0.075 3 98, 99, 99 99 0.5

Imidacloprid 0.001 7 99, 98, 94, 102, 111, 99, 98 100 5

0.050 3 101, 101, 102 101 0.4

0.075 3 98, 99, 99 98 0.7

Olefin 0.001 7 97, 83, 94, 100, 81, 100, 85 91 8

0.050 3 102, 102, 101 102 0.3

0.075 3 100, 101, 100 100 0.6

a Analytes are abbreviated: 5

- 0H = 5

- Hydroxy imidacloprid, Olefin = imidacloprid Olefin.

b See Appendix 4 of the study report for the analytical data summaries and refined data used to prepare this

summary.

Mean Recovery = mathematical average of all recoveries.

*Table 6 in study report

The limit of quantitation (LOQ) is defined as the lowest fortification level of an analyte at which

acceptable recovery has been achieved. The LOQ for total residue is the highest of the LOQ values

assigned to the individual analytes for a particular matrix.

The limit of detection (LOD) is defined as the lowest concentration of an analy te that can be determined

to be statistically different from a blank. The LODs were determined from method validation data

obtained from control samples fortified at the respective analyte LOQs. The LODs were calculated by

multiplying the standard deviatio n of recovery measurements at the LOQ by t 0.99 [where t 0.99 is the one

tailed t

- statistic at the 99% confidence level for the number of replicates (n)] 6 . The LOD for the total

imidacloprid residue in each matrix is the highest LOD value of any individual analyte for that particular

matrix.MRID 49103301 CDPR IMI Cotton (2011)

8 Summary of LOQs and LODs

Matrix Analyte LOQ (ppb ) LOD (ppb )

Cotton Nectar Imidacloprid 1.0 0. 1

5

- hydroxy Imidacloprid 1.0 0. 3

Imidacloprid Olefin 1.0 0. 3

Total Imidacloprid 1.0 0. 3

Cotton Leaves Imidacloprid 2.0 0. 6

5

- hydroxy Imidacloprid 2.0 0. 9

Imidacloprid Olefin 2.0 0. 6

Total Imidacloprid 2.0 0. 9

6. RESULTS:

Total imidacloprid was calculated as the sum of imidacloprid, 5

- hydroxy imidacloprid, and imidacloprid

olefin in parent equivalents. Summary statistics of the overall magnitude of total imidacloprid in cotton

nectar and leaves are shown below in Table 4

. In cases where individual analyte residues were l ess than

the LOD, a value of half the LOD was used to calculate total imidacloprid. The average total imidacloprid

residue in cotton leaves in the five sites ranged from 4.3 ppb to 23 ppb before the 2010 aerial (foliar)

application. Then, six days after ap plication, the average total imidacloprid residue in leaves ranged from

230 ppb to 1700 ppb. The average total imidacloprid residue in nectar ranged from 1.4 ppb to 4.2 ppb

prior to the 2010 aerial application. Then, six days after application, the average total imidacloprid

residue in nectar ranged from 16 ppb to 56 ppb.

The total imidacloprid residue data for cotton nectar and leav es are provided below in Table 5A and 5B

.

Table 4

. Magnitude of total imidacloprid residues in cotton nectar and leaves.

Commodity Soil Texture

Category a Days After

Treatment

(DAT) b Total Imidacloprid Residue Levels (ppb) c

N Min Max Highest

Avg. Site

Residue Median Mean Standard

Deviation

Cotton Nectar Heavy Soil Pre

- App

(

- 7 to

- 2 DAT ) 10 1

. 2 4 .3 4

. 2 2

. 7 2

. 8 1

. 0

Cotton Nectar Heavy Soil Post

- App

(6 DAT) 10 13 66 56 21 29 18

Cotton Leaves Heavy Soil Pre

- App

(

- 7 to

- 2 DAT ) 10 3

. 3 25 23 14 14 7

. 8

Cotton Leaves Heavy Soil Post

- App

(6 DAT) 10 15 0 19 00 17 00 36 0 77 0 67 0

a Classification of the soils was obtained from the Soil Survey Geographic (SSURGO) Database provided

by the Natural Resources Conservation Service and converted to soil texture categories.

b Duplicate samples of nectar and leaves from the five trials were analyzed at pre

- and post

a pplication sample intervals.

c Abbreviations used are as follows: Min is the lowest treated residue value; Max is the highest treated

residue value; Median is the geometric median of the treated residue values; Mean is the

mathematical average of the treated residue values; Standard Deviation is the standard deviation for a

small population of “N” samples.MRID 49103301 CDPR IMI Cotton (2011)

9 Table 5A. Imidacloprid Residue Data from Pre

- Application Cotton*Trial IdentificationLocation (City, State,Region)Plot NameCommodityRate, lb a.i./A(2008and 2009)bResidue Sample CollectionDAT (Days after 2010Tratement)cImidacloprid Residue (ppb)5-Hydroxy ImidaclopridResidue (ppb)Imidacloprid Olefin Residue(ppb)Total Imidacloprid Residue(ppb)

Nectar Pre

- Application Residue (ppb ) a

NT001 Kern County,

CA NAFTA

Region 10 Buttonwillow

Clay, Site S1

(Heavy) Nectar,

Pre

- App 0.72

- 7 2.7

3.5 <1

<1 <1

<1 3.0

3.8

Average

3.4

NT002 Kern County,

CA NAFTA

Region 10 2010 Lokern Clay, Site

S2 (Heavy) Nectar,

Pre

- App 0.76

- 3 2.6

2.0 <1

<1 <1

<1 2.9

2.3

Average

2.6

NT003 Kern County,

CA NAFTA

Region 10 Lokern Clay, Site

S3 (Heavy) Nectar,

Pre

- App 0.76

- 3 1.2

<1 <1

<1 <1

<1 1.5

1.2

Average

1.4

NT004 Kings County,

CA NAFTA

Region 10 2010 Houser Clay, Site

S4 (Heavy) Nectar,

Pre

- App 0.25

- 2 2.2

2.1 <1

<1 <1

<1 2.5

2.4

Average

2.5

NT005 Kings County,

CA NAFTA

Region 10 2010 Tulare Clay, Site

S5 (Heavy) Nectar,

Pre

- App 0.47

- 2 4.0

3.8 <1

<1 <1

<1 4.3

4.1

Average

4.2

Leaves Pre

- Application Residue (ppb ) a

NT001 Kern County,

CA NAFTA

Region 10 Buttonwillow

Clay, Site S1

(Heavy) Leaves,

Pre

- App 0.72

- 7 4.8

5.3 <2

2.1 <2

<2 7.8

8.5

Average

0.0082

NT002 Kern County,

CA NAFTA

Region 10 2010 Lokern Clay, Site

S2 (Heavy) Leaves,

Pre

- App 0.76

- 3 11.4

9.4 3.0

2.7 <2

<2 16

13

Average

14

NT003 Kern County,

CA NAFTA

Region 10 Lokern Clay, Site

S3 (Heavy) Leaves,

Pre

- App 0.76

- 3 <2

3.7 <2

<2 <2

<2 3.3

5.3

Average

4.3

NT004 Kings County,

CA NAFTA

Region 10 2010 Houser Clay, Site

S4 (Heavy) Leaves,

Pre

- App 0.25

- 2 16.3

17.8 3.1

3.0 <2

<2 21

22

Average

21MRID 49103301 CDPR IMI Cotton (2011)

10Trial IdentificationLocation (City, State,Region)Plot NameCommodityRate, lb a.i./A(2008and 2009)bResidue Sample CollectionDAT (Days after 2010Tratement)cImidacloprid Residue (ppb)5-Hydroxy ImidaclopridResidue (ppb)Imidacloprid Olefin Residue(ppb)Total Imidacloprid Residue(ppb)

NT005 Kings County,

CA NAFTA

Region 10 2010 Tulare Clay, Site

S5 (Heavy) Leaves,

Pre

- App 0.47

- 2 22.2

18.6 2.2

<2 <2

<2 25

21

Average

23

a See Appendix 4 of the study report for analytical data summaries and refined data used to prepare this summary.

Total imidacloprid is the sum of imidacloprid, 5

- hydroxy imidacloprid, and imidacloprid olefin.

b The rate reported is the total imidacloprid applied during the 2008 and 2009 growing seasons. See section 2.0 of

this report for further detail regarding historical imidacloprid applications to these sites.

c D AT= Days after Treatment. Negative value indicates that samples were collected prior to the 2010 application of

Provado 1. 6F.

*Table 8A in study report.

Table 5B. Imidacloprid Residue Data from 2010 Post

- Application Cotton. *Trial IdentificationLocation (City, State, Region)Plot NameCommodity2010 Total Seasonal Rate,lba.i./A(fl oz FP/A)bResidue SampleCollection(DAT)cImidacloprid Residue (ppb)5-Hydroxy ImidaclopridResidue (ppb)Imidacloprid Olefin Residue(ppb)Total Imidacloprid Residue(ppb)

Nectar Post

- Application Residue (ppb ) a

NT001 Kern County,

CA NAFTA

Region 10 Buttonwillow

Clay, Site S1

(Heavy) Nectar,

Post

- App 0.063

(5.0) 6 14

18.1 <1

1.0 <1

<1 15

20

Average

16

NT002 Kern County,

CA NAFTA

Region 10 2010 Lokern Clay, Site

S2 (Heavy) Nectar,

Post

- App 0.063

(5.0) 6 17.5

11.9 <1

<1 <1

<1 19

13

Average

16

NT003 Kern County,

CA NAFTA

Region 10 Lokern Clay, Site

S3 (Heavy) Nectar,

Post

- App 0.063

(5.0) 6 20.5

14.8 1.2

<1 <1

<1 22

16

Average

19

NT004 Kings County,

CA NAFTA

Region 10 2010 Houser Clay, Site

S4 (Heavy) Nectar,

Post

- App 0.063

(5.0) 6 31.7

42 1.5

2.1 <1

<1 34

45

Average

0.039MRID 49103301 CDPR IMI Cotton (2011)

11Trial IdentificationLocation (City, State, Region)Plot NameCommodity2010 Total Seasonal Rate,lba.i./A(fl oz FP/A)bResidue SampleCollection(DAT)cImidacloprid Residue (ppb)5-Hydroxy ImidaclopridResidue (ppb)Imidacloprid Olefin Residue(ppb)Total Imidacloprid Residue(ppb)

NT005 Kings County,

CA NAFTA

Region 10 2010 Tulare Clay, Site

S5 (Heavy) Nectar,

Post

- App 0.063

(5.0) 6 42.8

61.5 2.4

3.4 <1

<1 46

66

Average

56

Leave Post

- Application Residue (ppb) a

NT001 Kern County,

CA NAFTA

Region 10 Buttonwillow

Clay, Site S1

(Heavy) Leaves,

Post

- App 0.063

(5.0) 6 135

269 14.5

24.1 2.9

4.3 150

300

Average

230

NT002 Kern County,

CA NAFTA

Region 10 2010 Lokern Clay, Site

S2 (Heavy) Leaves,

Post

- App 0.063

(5.0) 6 243

273 50.1

42.2 10.1

8.6 300

320

Average

310

NT003 Kern County,

CA NAFTA

Region 10 Lokern Clay, Site

S3 (Heavy) Leaves,

Post

- App 0.063

(5.0) 6 231

341 42.7

43.7 9.4

10.8 280

400

Average

340

NT004 Kings County,

CA NAFTA

Region 10 2010 Houser Clay, Site

S4 (Heavy) Leaves,

Post

- App 0.063

(5.0) 6 1540

1820 55.4

55.9 14.6

13.4 1600

1900

Average

1700

NT005 Kings County,

CA NAFTA

Region 10 2010 Tulare Clay, Site

S5 (Heavy) Leaves,

Post

- App 0.063

(5.0) 6 792

1460 63.1

95.2 17.1

25.7 870

1600

Average

1200

a See Appendix 4 of the study report for analytical data summanes and refined data used to prepare th1s summary.

Total imidacloprid is the sum of imidacloprid, 5

- hydroxy imidacloprid, and imidacloprid olefin.

b Total Seasonal Rate (lb ai/A) = Provado 1.6 F foliar application to cotton in 201 0. The rate of the formulated

product applied (fl oz FP/A) is indicated in parenthesis. See section 2.0 of this report for further detail regarding

historical imidacloprid applications to these sites.

c DAT = Days after Treatment. Samples were collected 5 to 6 days following the 2010 application of

Provado 1.6 F.

*Table 8B in study report.

7. STUDY VALIDITY/ CLASSIFICATION AND STUDY LIMITATIONS

Classification/Utility for Bee Risk Assessment. This study is classified as SUPPLEMENTAL because the

application rate is far below the maximum annual application rate (so this is not a worst case scenario).

The 2010 application rate of 0.063 lbs. a.i./acre, represents the highest allowable single foliar

application rate, but it does not repres ent the maximum foliar rate per season, resulting from 5

applica tions, of 0.31 lbs./acre/season. The study also does not represent the maximum amount of

imidacloprid allowable per season on cotton, which is 0.5 lbs./acre/season. The submitted data providesMRID 49103301 CDPR IMI Cotton (2011)

12 information on potential residues in nectar from a single foliar application. However, the residues do not

represent cotton treated at the highest label rate possible in accordance with the label. The study

provides data that does not meet all of DPR’s re evaluation data requirements for cotton. Data from a

worst case imidacloprid application scenario (including soil applications) at the maximum seasonal rate

allowed by imidacloprid product labels is still needed.

Temporal Variability in Residues . Samples were collected 2

- 7 days before and 6 days after the aerial

application in 2010 but a decline in residues was not recorded because only one time point was sampled

after application. This study was not designed for temporal analysis of declining concentratio ns, but

rather, to provide a snapshot of residue concentrations during flowering.

Spatial Variability in Residues. All five sites were in Kern and King s County in the Southern Central

Valley (i.e., San Joaquin Valley) of California. All of the sites had s imilar climatic conditions. All five sites

had soil with fine (heavy) texture. Medium and coarse soils were not included in this study.

Pesticide Carryover. The extent to which prior year applications of imidacloprid contributed to year

- to

year carryover was not analyzed by the study authors.

Additionally, if the data is to be used as part of a risk assessment, then the data should be re

- analyzed

taking the following uncertainties into consideration: (1) One of the five sites had two chemigation

applications in 2009 bu t no application at all in 2008 ( NT004) ; and (2) This study did not distinguish

between floral and extra

- floral nectar.

8. CONCLUSION

This report provides data for residues of total imidacloprid in five cotton trials conducted in clay soils

(soil classification: heavy). All plots had received prior applications (2008 and/or 2009) of imidacloprid

containing products at rates ranging from 0.18 to 0.38 lb ai/A, and received a single application of

Provado 1.6 F to cotton in 2010 at 0. 063 lb imidacloprid/A (5.0 fl oz formulated product/A) during

flowering (BBCH 61 to BBCH 67). The average total imidacloprid residue in nectar ranged from 1.4 ppb

to 4.2 ppb prior to the 2010 aerial application. Then, six days after application, the averag e total

imidacloprid residue in nectar ranged from 16 ppb to 56 ppb. The study does not represent the

maximum amount of imidacloprid allowable per season on cotton and thus this study is found to be

supplemental

.

9. REFERENCES

1. Hoelscher, A. 1998. Phys ical and chemical properties of the active ingredient imidacloprid. Bayer CropScience Report No. M0

- 03

- 006885, M

- 1 05510

- 01

- 1.

2. Talbott! T. D. 1991. Product Chemistry of BAY NTN 33893 Technical. Bayer CropScience
Report No. MRID M004227

- 01

- 1.

3. Krohn, J. 1993. Vapour Pressure Curve of lmidacloprid. Bayer CropScience Laboratory
Project ID 14 200 0804. Report No. M

- 004042

- 01

- 1.

4. Brungardt, Jaime 2010. An Analytical Method for the Determination of Residues of
lmidacloprid and its Metab olites lmidacloprid Olefin and 5

- Hydroxy lmidacloprid in BeeMRID 49103301 CDPR IMI Cotton (2011)

13 Relevant Matrices Using LC/MS/MS. Bayer Report No. NT

- 005

- P1 0

- 01.

5. Schoning, R. 1999. Residue Analytical Method for the Determination of Residues of
lmidacloprid, Hydroxy

- lmidacloprid, Olefin

- lmidacloprid, YRC 2894, YRC 2894

- Amide, and

4

- Hydroxy

- YRC 2894

- Amide in Plant Material by HPLC with Electrospray MS/MSDetection.
Method No. 00573. Report No. MR

- 853/98.

6. Office of Pesticide Programs , US EPA. 2000. Assigning values to non

- detected/nonquantified
pesticide residues in human health food exposure assessments. EPA Docket

#OPP

- 00570A