MRID 49665201 CDPR IMI Soil and Foliar Tomato Study

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Reference

Gould, T., and Jerkins, E. (2015) Determination of the Residues of Imidacloprid, 5-Hydroxy 

Imidacloprid, and Imidacloprid Olefin in Bee Relevant Matrices Collected from Tomatoes Following 

Application of Imidacloprid Over Two Successive Years: Final Report. Project Number: EBNTN012. 

Unpublished study prepared by Bayer CropScience 466pg. MRID 49665201, CDPR study ID 285680, 

Data Volume 51950-0899, Tracking ID#270950

1. STUDY INFORMATION

Chemical: Imidacloprid PC Code 129099

Test Material: Admire Pro Systemic 

Protectant (SC) Purity: 43.50% a.i. w.w.

Study Type:

Non-Guideline field residue study on tomatoes to establish imidacloprid and 

metabolite levels in pollen, nectar, and leaves after at plant soil drip/drench 

application followed by two foliar spray applications in each of two successive 

years and three different soil types (fine, medium, and coarse).

Sponsor:

Bayer CropScience

2T.W. Alexander Drive

Research Triangle Park, NC 

USA 27709

Experiment Start and

End Date:

July 2, 2013 -

April 9, 2015

Sponsor Study 

ID: EBNTN012

Study Locations:

9 Field Trials in the 

cities of:

Fresno, Guadalupe, 

Kerman, Porterville, 

Sanger, San Joaquin, San 

Luis Obispo, California

Study 

Completion 

Date:

June 29, 2015

GLP Status: GLP-compliant; protocol reviewed by EPA, PMRA, CDPR.

[CDPR study ID 254887, Data Volume 51950-0757, Tracking ID# 241047.]

2. REVIEWER INFORMATION

Primary Reviewers:

California 

Department of 

Pesticide Regulation

John Troiano, Ph.D., Research Scientist III, Environmental Monitoring 

Branch

Richard Bireley, Senior Environmental Scientist (Specialist), Ecotoxicology 

Group, Pesticide Registration Branch

Denise Alder, Senior Environmental Scientist (Specialist), Lead Reevaluation 

Coordinator, Pesticide Registration Branch 

Russell Darling, Environmental Scientist, Reevaluation Coordinator, 

Pesticide Registration Branch

3. EXECUTIVE SUMMARY

A total of nine field trials were conducted to measure the magnitude of imidacloprid residues in 

transplanted tomato pollen and in/on transplanted tomato leaves following three applications of 

Admire Pro Systemic Protectant, EPA Reg. No. 264-827 in each of two successive years. Admire Pro 

Systemic Protectant is a suspension concentrate formulation containing 550 g/L imidacloprid. Five trials 

have one year of data and four trials have two years of data.
MRID 49665201 CDPR IMI Soil and Foliar Tomato Study

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Trials NT017-13ZB and NT039-13ZA through NT042-13ZA were started/restarted in 2014, so only one 

year of data from these trials are reported here.

Across all reported trials and years, treated plots received one soil (in-furrow) drip/drench application of 

Admire Pro five to seven days after tomato transplantation followed by two equivalent Admire Pro foliar 

spray applications per planting season. Individual soil application rates ranged from 0.37 to 0.38 lb 

imidacloprid/A per application (0.42 to 0.43 kg/ha). The interval between the soil and first foliar 

applications was 48 to 78 days. Individual foliar application rates ranged from 0.058 to 0.062 lb 

imidacloprid/A/application (0.066 to 0.070 kg/ha). All foliar applications were made to flowering tomato 

plants, after the first two sampling events were complete. The interval between foliar applications was 

four to five days. The foliar spray volumes ranged from 50 to 101 gal/A, with the exception of the 

second foliar spray in 2013 to trial NT018-13ZA (48 gal/A). Total seasonal application rates were 0.50 lb 

imidacloprid/A (0.56 kg/ha).

All applications were made using ground-based equipment. The adjuvant Dyne-Amic (0.25 or 0.5 % v/v) 

was used in all foliar applications, with the exception of the first foliar application in trial NT017-13ZB 

and both foliar applications in trial NT039-13ZA. 

One bee tunnel was erected on untreated plot UTC, and two bee tunnels were erected on treated plot 

TRTD, except in trials NT013-13ZA, NT040-13ZA, and NT041-13ZA, when only one TRTD tunnel was 

erected. Bumble bee (Bombus impatiens) colonies (1 to 3 per tunnel) were placed in each tunnel for the 

collection of pollen. One sample was collected per bee tunnel, yielding two TRTD samples and one UTC 

sample at each sampling interval, except in trials NT013-13ZA, NT040-13ZA, and NT041-13ZA, when two 

replicate samples were collected from the single erected TRTD tunnel. 

Tomato leaf and pollen samples were collected at four sampling intervals: two samples were collected 

after the soil application, approximately 14 days apart (31 to 68 and 45 to 77 days after the soil 

application, respectively), and two samples were collected after the last foliar application, 

approximately 14 days apart (2 to 8 and 16 to 22 days after the last foliar application, respectively). At 

each interval, fresh bumble bee colonies were placed in each bee tunnel, and the bumble bees were 

allowed to forage from the tomato flowers for several days. Then, bumble bees carrying pollen were 

collected from the tunnels, and the pollen was removed from the bees. To ensure a large enough pollen 

sample for analysis, some trials collected bees over multiple days (up to seven) per sampling event. 

Multi-day pollen samples from the same sampling interval and bee tent were composited together into 

one sample vial.

During the described sampling intervals, composite samples of tomato leaves were collected from 

within the tunnels of the treated plots. Composite samples of tomato pollen and leaves were collected 

from the control plot tunnel of each trial on the same days and using the same methods as samples 

collected from the treated plots.

The residues of Admire Pro Systemic Protectant (imidacloprid, 5-hydroxy imidacloprid, and imidacloprid 

olefin) were quantitated by high performance liquid chromatography/triple stage quadrupole mass 

spectrometry (LC/MS/MS) and LC/high resolution mass spectrometry (LC/HRMS) using stable 

isotopically labeled internal standards. The individual analyte residues were summed to give a total 

imidacloprid residue.
MRID 49665201 CDPR IMI Soil and Foliar Tomato Study

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Storage stability studies indicate that the imidacloprid residues would have been stable during frozen 

storage for at least for at least 1,080 days (36 months) in tomato leaves prior to analysis. Transit stability 

samples showed that imidacloprid residues were stable in pollen for the duration of the study. The 

maximum storage period of frozen samples in this study for Admire Pro Systemic Protectant was 

561 days for tomato leaves and 560 days for tomato pollen.

4. STUDY VALIDITY

Guideline Followed: Non-guideline study (protocol was reviewed by U.S. EPA/PMRA/CDPR)

Guideline Deviations: N/A

Other Deviations: N/A

Classification: Quantitative

Rationale: The data from the study will provide a basis for developing a 

quantitative assessment of exposure levels to bees that can be used in a 

risk assessment scenario.

Reparability: N/A

5. MATERIALS AND METHODS

Test Material Characterization

Test item:

Admire Pro Systemic Protectant 

(Imidacloprid) 550 g a.i./L SC CAS #: 138261-41-3

Description: Suspension concentrate (SC) Purity: 43.50% w/w

Lot No./Batch No. Batch No. NK41CX0578 Density: 1.41 – 1.54 g/mL

Material Source: Bayer CropScience Cert. # 213CJ2446

Material Receipt 

Date: Not Reported

Analysis 

Date: 12/03/2012

Expiration Date: 12/03/2014 Solubility: 0.51 to 0.61 g/L

Storage of Test 

Material:

Ambient (35-86oF) 

except trials NT010-13ZA and

NT016-13ZA when the 

temperature briefly reached 

95oF; trial NT017-13ZB when 

the temperature briefly 

reached 90oF; and, trial NT018-

13ZA when the temperature 

reached as low as 32oF and as 

high as 90oF.

Sample 

Storage:

 -27oC to -7oC

-16oF to 19oF

5A. STUDY DESIGN

This study requirement was part of the imidacloprid special review at the California Department of 

Pesticide Regulation (CDPR). The study design and protocol were approved by CDPR prior to study 

initiation. This study was conducted using GLP standards and following an approved protocol. The study 

initiation date was June 21, 2013. The experimental start date was July 02, 2013 (first application), and 

the experimental end date was April 09, 2015 (last analysis).

Nine trials in California were conducted for this study, representing all three soil texture categories 

(fine, medium, and coarse). Each trial, includes two treated plots, both to be planted and treated for two 
MRID 49665201 CDPR IMI Soil and Foliar Tomato Study

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consecutive years. To date, Bayer CropScience has collected at least one year of residue data from all 

nine trial sites (five coarse texture fields, one medium, and three fine). Two years of data collection are 

complete at four sites (two coarse texture sites, one medium, and one fine). Bayer CropScience 

continues work on a second year of data collection on five sites in the 2015 growing season (three 

coarse texture sites and two fine) which is anticipated in January 2016.

Indeterminate (continuously flowering and fruiting) tomato varieties representing those commonly 

grown in the area of the trials and agronomic practices typical for commercial production of tomato 

were used at all trial locations. Once bloom began, the tomato plots were sampled at four intervals. The 

plots were sampled twice at early bloom approximately 14 days apart, prior to any foliar sprays, to 

assess the residues in bee-relevant matrices resulting from the at-plant soil application. The flowering 

tomatoes were then given two foliar applications of imidacloprid. The tomatoes were sampled twice 

more after the last foliar application, approximately 14 days apart, to assess the residues resulting from 

the soil application at planting plus two additional at-bloom foliar applications.

Homogenization and analysis of the samples from this study were performed by Bayer CropScience in 

Research Triangle Park (RTP), NC. Final report preparation was performed by Critical Path Services, LLC, 

located in RTP, NC.

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

final report under Notebook Number EBNTN012 at Bayer CropScience, 2 T. W. Alexander Drive, RTP, NC 

27709.

5B. APPLICATION TIMING AND RATES

The full study report provides (1) Chronological listing of significant study dates (Appendix 1); (2) Field 

report summaries for each trial detailing the actual amount of test substance applied, plot sizes, dates of 

treatment, dates of sample collection, maintenance chemicals, climatic data, and irrigation data 

(Appendix 2); and (3) Quality assurance statements for each trial (Appendix 3). Information on 

application timing is provided in Table 1. Soil and meteorological characteristics of the study sites are 

provided in Table 2 and Table 3. Table 4 provides the sampling dates and tomato developmental stages. 

BBCH or Biologische Bundesanstalt, Bundessortenamt und CHemische Industrie, identifies the specific 

phenological development stages of tomato. Plot TRTD received one soil (in-furrow) drip/drench 

application of Admire Pro five to seven days after tomato transplantation followed by two equivalent 

Admire Pro foliar applications per planting season. Individual soil application rates ranged from 0.37 to 

0.38 lb imidacloprid/A per application (0.42 to 0.43 kg/ha). The interval between the soil and first foliar 

applications was 48 to 78 days. Individual foliar application rates ranged from 0.058 to 0.062 lb 

imidacloprid/A/application (0.066 to 0.070 kg/ha). All foliar applications were made to flowering tomato 

plants, after the first two sampling events were complete. The interval between foliar applications was 

four to five days. The foliar spray volumes ranged from 50 to 101 gal/A, with the exception of the 

second foliar spray in 2013 to trial NT018-13ZA (48 gal/A). Total seasonal application rates were 0.50 lb 

imidacloprid/A (0.56 kg/ha).

Temperature and precipitation data were recorded for each trial and are summarized in Appendix 2 of 

the study report EBNTN012. Temperatures recorded during the field phase of the study were similar to 

average historical records except in trial NT013-13ZA, which had a slightly warmer spring 2014. 
MRID 49665201 CDPR IMI Soil and Foliar Tomato Study

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Recorded rainfall was slightly lower than historical records in trials NT010-13ZA, NT016-13ZA, and 

NT018-13ZA. However, there were no significantly unusual weather conditions that would affect the 

conclusions of the study. CDPR requested that the trial sites be distributed as three coarse, three 

medium, and three fine textured soils [per USDA’s Soil Survey Geographic database (SSURGO) mapping 

units]. There are nine trial sites in this tomato study design: three in fine texture soils, one in medium, 

and five in coarse; three sandy loams (as determined by SSURGO and shown in the general texture 

description of were considered coarse textured. One to two years of data for each site are presented in 

this report. The three fine texture sites have one to two years of data (trial NT016-13ZA has two years of 

data and trials NT039-13ZA and NT040-13ZA each have one year, for four total trial years of data). The 

medium texture site has two years of data (trial NT013-13ZA). The five coarse texture sites have one to 

two years of data (trial NT017-13ZB, NT041-13ZA, and NT042-13ZA each have one year of data; trials 

NT010-13ZA and NT018-13ZA have two years of data). Therefore, there are four trial years in fine 

texture soils, two trial years in medium soil, and seven trial years in coarse soils. See Table 3 for more 

site specific soil information.
MRID 49665201 CDPR IMI Soil and Foliar Tomato Study

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Table 1. Summary of soil and foliar application rates and timing*.
MRID 49665201 CDPR IMI Soil and Foliar Tomato Study

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a

Values for spray volume, rate, and total rate have been rounded using values provided in Appendix 2.

b

NA = Not applicable. c

Trials NT017-13ZB and NT039-13ZA through NT042-13ZA were started/restarted in 2014, so only 

one year of test substance application data are reported.

d

NR = Not reported; the BBCH at this application was not reported by the Principal Field Investigator.

*Table 4 of the study report.
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5C. STUDY SITE LOCATION AND CHARACTERISTICS 

Table 2. Soil and meteorological characteristics of the study sites*.

Trial

IDa

Trial Location (City, 

Country/State, Year, GPS 

Coordinatesb)

Soil Characteristicsc MeteorologicalDatad

OM (%) pH Variety

CEC

(meq/

100 g

soil)

% 

Sand

% 

Silt

% 

Clay Type

Total 

Rainfall 

(in)

Temp. Range

(°F)

NT010-

13ZAv

Porterville, CA, 2013-2014

(36.005, -119.0721) 1.2 7.7 13.7 58 36 6

Sandy 

Loam 4.56 29 97

Garden 

Delight

NT013-

13ZA

Fresno, CA, 2013-2014

(36.7362, -119.87476) 0.7 7.7 9.1 71 20 9

Sandy 

Loam 3.62 30 102 Big Beef

NT016-

13ZA

Porterville, CA, 2013-2014

(36.0348, -118.9964) 1.7 7.0 29.4 44 21 35

Clay 

Loam 4.62 29 97

Garden 

Delight

NT017-

13ZB

Guadalupe, CA, 2014

(N34.96917, W120.60196) 0.6 7.4 28.6 75 14 11

Sandy 

Loam 0.01 51 74 Sungold

NT018-

13ZA

Sanger, CA, 2013-2014

(36.739659, -119.576766) 0.8 7.1 4.9 78 12 10

Sandy 

Loam 4.34 28 100

Cherry 

Tomato

NT039-

13ZA

San Luis Obispo, CA, 2014

(35.306478, -120.677548) 2.8 7.5 32.7 46 21 33

Sandy 

Clay 

Loam 0 50 78 Naomi

NT040-

13ZA

San Joaquin, CA, 2014

(36.59885, -120.20671) 1.4 8.4 62.0 11 24 65 Clay 0.0 52 105 Naomi

NT041-

13ZA

Kerman, CA, 2014

(36.79380, -120.05320) 0.4 5.4 4.6 79 18 3

Sandy 

Loam 0.11 58 98 Naomi

NT042-

13ZA

Sanger, CA, 2014

(36.70034, -119.461982) 0.4 6.7 4.5 62 29 9

Sandy 

Loam 0.48 56 97

Cherry 

Tomato 

(Golden 

Gem)

a Site conditions listed are for the TRTD plot. For UTC plot conditions, see Appendix 2 of the study 

report.

b GPS coordinates are in the form (latitude, longitude).

c These soil characteristics are based on analyses of soil samples collected from within approximately

500 ft of the treated plot. Abbreviations used: %OM = percent organic matter; CEC = cation exchange 

capacity.

d Data is for the interval of the month of first application through the month of last sampling.

Meteorological data were obtained from nearby government weather stations.

* Combined table from Table 3A and Table 8 of the study report.

Table 3. SSURGO soil characteristics of the study sites*.

Trial

ID

Trial

Location

General Texture

Description

(SSURGO)

Component

%a

CDPR

Texture

Category

Drainage

Class

Hydrologic

Group Runoff

Particle

Size

NT010-

13ZA

Porterville, 

CA

Tujunga loamy

sand,

0-2% slopes 85 Coarse

Somewhat

excessively 

drained A Negligible NAb
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Trial

ID

Trial

Location

General Texture

Description

(SSURGO)

Component

%a

CDPR

Texture

Category

Drainage

Class

Hydrologic

Group Runoff

Particle

Size

NT013

-13ZA Fresno, CA Ramona loam 80 Medium

Well 

drained C Low

Fine

Loamy

NT016

-13ZA

Porterville, 

CA

Centerville clay,

2-9% slopes 80 Fine

Well 

drained D NA Fine

NT017

-13ZB

Guadalupe, 

CA

Mocho sandy

loam,

0-3% slopes 85 Coarse

Well 

drained A Negligible

Fine

Loamy

NT018

-13ZA Sanger, CA

Delhi loamy sand,

0-3% slopes 85 Coarse

Somewhat 

excessively 

drained A Very Low NA

NT039

-13ZA

San Luis

Obispo, CA

Salinas silty clay 

loam, 0-2% slope 85 Fine

Well

Drained C Medium

Fine 

loamy

NT040

-13ZA

San

Joaquin, CA

Merced clay, 

slightly saline 85 Fine

Very Poorly

Drained C Medium Fine

NT041

-13ZA Kerman, CA

Hanford coarse 

sandy loam 85 Coarse

Well 

drained A Very Low

Coarseloamy

NT042

-13ZA Sanger, CA

Hanford fine sandy

loam, gravelly 

substratum 85 Coarse

Well

Drained A Very Low

Coarseloamy

a Major component of the soil as a percentage of totalsoil.

b NA = Not applicable.

5D. SAMPLE COLLECTION, HANDLING, PROCESSING

Tomato Plant Matrices. 

Composite samples (one per each bee tunnel) of tomato leaves and pollen were collected from plots 

UTC and TRTD in years one and two of the study, except in trials NT017-13ZB and NT039-13ZA through 

NT042-13ZA, which were started/restarted in 2014 and have only completed one year of the study. All 

tomato leaf and pollen samples were collected from within the erected bee tunnels on both plots at 

four sampling intervals. The first and second samples were collected at early bloom approximately 

14 days apart, prior to any foliar sprays (31 to 68 and 45 to 77 days after the soil application, 

respectively). The third and fourth samples were collected after the last foliar application, approximately 

14 days apart (2 to 8 and 16 to 22 days after the last foliar application, respectively). UTC samples were 

collected at the same sampling intervals and via the same methods as the TRTD samples.

All samples were protected from sunlight and placed in field coolers containing ice substitute. Upon 

arrival at the site facility, all composite leaf samples were placed directly into frozen storage. All 

composite pollen samples were placed directly into frozen storage after their removal from the bumble 

bees (used as a sampling device).

Composite samples were placed into labeled (study number and sample number) containers for 

shipment. All samples were frozen within four hours of their collection. Samples were shipped and 

remained frozen until receipt at Bayer CropScience (RTP, NC).
MRID 49665201 CDPR IMI Soil and Foliar Tomato Study

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During the described sampling intervals, duplicate composite samples (one per bee tunnel) of tomato 

leaves were collected from the treated plots (one day of sampling only).

All composite leaf samples were collected by hand from different areas of the tomato plants (top and 

middle, left and right). Each composite sample of leaves contained a target of 150 g collected from any 

number of healthy-appearing plants located inside the bee tunnel.

Tomato Pollen Samples and Bee Handling. 

Details on the pollinator portions of the study are located in Appendix 5. One bee tunnel was erected on 

untreated plot UTC, and two bee tunnels were erected on treated plot TRTD, except in trials NT013-

13ZA, NT040-13ZA, and NT041-13ZA, when only one TRTD tunnel was erected. Bumble bee (Bombus 

impatiens) colonies (1 to 3 per tunnel) were placed in each tunnel for the collection of pollen. One 

sample was collected per bee tunnel, yielding two TRTD samples and one UTC sample at each sampling 

interval, except in trials NT013-13ZA, NT040-13ZA, and NT041-13ZA, when two replicate samples were 

collected from the single erected TRTD tunnel.

At each testing location, the control and treated plots were divided into sampling subplots for the 

construction of bee-tight, ventilated mesh-covered tents (tunnels). When the tomato bloom was 

sufficient to support pollen sampling after the first (soil) application, the tunnels were erected. The 

tunnels were 100 to 210 feet long and 20 to 40 feet wide, and each tunnel enclosed four to eight rows 

of tomato plants. In some trials, the tunnel was removed after sampling interval two to allow for the 

foliar applications and re-erected prior to sampling interval three.

Normally developed, apparently healthy bumble bees (Bombus impatiens) were used for pollen 

collection. One to three bumble bee colonies were placed in each bee tunnel. Bumble bee colonies were 

contained in Class A research hives, Class C garden hives, or boxed colonies. In all trials, the bumble bee 

colonies were allowed access to sugar water feeders or nectar/syrup bags.

Fresh bumble bee colonies were placed in each bee tunnel prior to each sampling event; the bumble 

bees were allowed to forage from the tomato flowers for several days. Bumble bees were observed for 

visible pollen collected in the pollen basket on their legs. Bees with pollen were collected using nets or 

vacuums and placed in containers with dry ice at the field. The bees were transported to the site facility 

for pollen removal. All available pollen was collected from the bees using an appropriate tool such as 

tweezers or forceps, and the pollen samples were placed in 40-mL amber glass containers.

To ensure a large enough pollen sample for analysis, some trials collected bees over multiple days (up to 

seven) per sampling event (see Appendix 2). Multi-day pollen samples from the same sampling interval 

and bee tent were composited together into one sample vial. Bumble bee colonies were removed from 

the tents after the end of the sampling event.

Bumble bee colonies were removed from the tents after the end of the sampling event.
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Table 4. Sampling dates and tomato developmental stages for plant residue analysis*

Pollen and Leaf Sampling

Year 1 Year 2 Year 1 Year 2

BBCH† Dates‡ BBCH† Dates‡ BBCH† Dates‡ BBCH† Dates‡

Fresno = NT013-13ZA Sanger 1 = NT018-13ZA

XX3

62-68 DASA,

-16 to -10 

DA1FA

XX

31-33 DASA, 

-17 to -15 DA1FA

71 55 DASA, 

-17 DA1FA

61

52-54 DASA, 

-20 to -18 DA1FA

XX

75-77 DASA,

-3 to -1 

DA1FA

XX

45-47 DASA, 

-3 to -1 DA1FA

83

70-71 DASA, 

-2 to -1 

DA1FA

71 69 DASA, 

-3 DA1FA

XX 2-8 DA2FA XX 4 DA2FA1 85 6 DA2FA 72 7 DA2FA

XX 17-20 DA2FA XX 19-21 DA2FA 85 20 DA2FA 86 20 DA2FA

Guadalupe = NT017-13ZB Sanger 2 = NT042-13ZA

69 46 DASA, 

-15 DA1FA

TBC2 XX

36-38 DASA, 

-16 to -14 

DA1FA

TBC

72 59 DASA, 

-2 DA1FA

TBC XX

49-51 DASA, 

-3 to -1 

DA1FA

TBC

74 8 DA2FA TBC XX 5-6 DA2FA TBC

79 19-20 DA2FA TBC XX 16-18 DA2FA TBC

Kerman = NT041-13ZA San Joaquin = NT040-13ZA

XX

33-37 DASA, 

-17 to -13 

DA1FA

TBC XX

35-37 DASA, 

-17 to -15 

DA1FA

TBC

XX 49 DASA, 

-1 DA1FA1 TBC XX 50 DASA, -2 DA1FA1 TBC

XX 4-7 DA2FA TBC XX 4-6 DA2FA TBC

XX 19-21 DA2FA TBC XX 19-22 DA2FA TBC

Porterville 1 = NT010-13ZA San Luis Obispo = NT039-13ZA

XX

44-45 DASA,

-13 to -12 

DA1FA

XX 61 DASA, 

-14 DA1FA

XX 50 DASA, 

-14 DA1FA1 TBC

XX

54-56 DASA,

-3 to -1 

DA1FA

XX

72-73 DASA, 

-3 to -2 DA1FA

XX

61-63 DASA, 

-3 to -1 

DA1FA

TBC

XX 4 DA2FA1 XX 4-6 DA2FA XX 5-6 DA2FA TBC

XX 20-21 DA2FA XX 17-19 DA2FA XX 17-18 DA2FA TBC

Porterville 2 = NT016-13ZA

XX

48-50 DASA,

-13 to -11 

DA1FA

XX

59-61 DASA,

-16 to -14 

DA1FA

XX 59 DASA, 

-2 DA1FA1 XX

72-73 DASA, 

-3 to -2 DA1FA
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Pollen and Leaf Sampling

Year 1 Year 2 Year 1 Year 2

BBCH† Dates‡ BBCH† Dates‡ BBCH† Dates‡ BBCH† Dates‡

XX 5 DA2FA1 XX 4-6 DA2FA

XX 20 DA2FA XX 17-19 DA2FA

†

BBCH = Biologische Bundesanstalt, Bundessortenamt und CHemische Industrie growth stage scale for tomato.

‡

DASA = Days after the soil (in-furrow) application; DA1FA = days after the first foliar application;

DA2FA = days after the second foliar (and last) application. A negative number designates days prior to the 

indicated application. Ranges indicate that samples were collected over several days and composited together to 

create a large enough volume for analysis.

1

Leaf sampling ONLY. No pollen data, insufficient sample weight.

2

TBC = To Be Collected; the samples will be collected when the second year of the trial is performed.

3

BBCH XX indicates no growth stage reported in the field data summary.

*Combination of Appendix 1 and Appendix 5 of the study report.

Sample Storage.

Composite samples were placed into labeled (study number and sample number) containers for 

shipment. All samples were frozen within four hours of their collection. Samples were shipped and 

remained frozen until receipt at Bayer CropScience (RTP, NC).

5E. ANALYTICAL METHODS

The analytical methods1-2 used in this study measured the residues of imidacloprid, 5-hydroxy 

imidacloprid, and imidacloprid olefin in tomato leaves and pollen. These data are reported in 

Appendix 4 of the full study report titled, “Analytical Report for EBNTN012 Determination of the 

Residues of Imidacloprid, 5-Hydroxy Imidacloprid, and Imidacloprid Olefin in Bee Relevant Matrices 

Collected from Tomato Plants Following Soil and Foliar Applications of Admire Pro Over Two Successive 

Years.”

All neat analytical reference standards were stored frozen prior to dilution. All reference standard 

solutions were prepared in parent equivalents and corrected for purity during initial preparation. The 

reference standard solutions were stored refrigerated or frozen and have been shown to be stable for 

the length of storage time required for this study.

For the tomato leaves a 2.5 g sample was weighed into a 50-mL polypropylene conical centrifuge tube, 

and 10 mL HPLC-grade water was added. The tube was mixed manually for 1 min, followed by adding 

20 mL of acetonitrile and mechanical shaking (HS501 digital, IKA-Werke, Wilmington, NC) for an 

additional 1 min. Then, 3 g of MgSO4 and 1.5 g of NaCl were added. The sample was amended with a 

mixed internal standard solution, capped, and shaken for 1 min. For leaf samples which were found to 

contain high residues of imidacloprid (>2 ppm), the sample was amended with a 10X mixed internal 

standard solution before the salts were added. The sample was centrifuged. For low imidacloprid 

residue samples, 20 mL of organic supernatant was transferred into a separate 50-mL polypropylene 

conical centrifuge tube containing 0.3 g of Bondesil-PSA and 1.8 g of MgSO4. For high imidacloprid 

residue samples, 2.0 mL of organic supernatant and 18.0 mL of acetonitrile were transferred into a 

separate 50-mL polypropylene conical centrifuge tube containing 0.3 g of Bondesil-PSA and 1.8 g of 

MgSO4, which was capped and shaken for 1 min. The sample extract was centrifuged, and a 1.25 mL 

aliquot of supernatant was transferred into a clean culture tube. The sample aliquot was evaporated to 
MRID 49665201 CDPR IMI Soil and Foliar Tomato Study

13

near dryness on the Turbo-Vap (Biotage, Charlotte, NC). The solid was reconstituted with 1.25 mL of 

9:1 H2O:MeOH and transferred into a 2-mL sample vial for LC/MS/MS analysis.

For pollen, a 0.1 g sample was weighed into a 2-mL centrifuge tube containing 2.8 mm steel balls. If the 

available pollen amount was less than 0.1 g but greater than 0.025 g for a sample, the sample was 

considered sufficient for analysis. A 1 mL portion of methanol/water (3:1 v/v) was added, and the 

mixture was homogenized with a bead mixer at 5000 beats/min for 1 min on a Precellys homogenizer 

(Bertin Technologies, Rockville, MD). The isotopically labeled internal standards were added and mixed, 

and the mixture was centrifuged at 12,000 rpm for 2 min. The supernatant was transferred into a clean 

culture tube containing 2.5 mL of water and was evaporated to an aqueous remainder, then applied to a 

3-mL ChemElut SPE cartridge. After 10 to 15 min, the cartridge was washed with 4 mL of hexane/ethyl 

acetate (1:1 v/v) three times into a clean culture tube. The combined eluates were evaporated to 

dryness. The analytes were dissolved from the tube with 0.5 mL of MeOH/H2O (1:4 v/v). The solution 

was transferred into a 2 mL sample vial for analysis by LC/high resolution mass spectrometry (LC/HRMS).

Quantitation of each analyte was based on the daughter ion transitions of the analyte and the 

respective internal standard analog. The responses of the LC/MS/MS and LC/HRMS systems to each 

analyte and its internal standard were measured in samples and in standards, and a relative 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.

The relative responses of imidacloprid and its analytes were measured over the range of 0.00012 to 

0.040 ppm (0.0006 to 0.200 ppm sample equivalent). The analyte relative responses were fit to a 

linearity curve calculated using linear regression analysis with 1/x weighting (Thermo Finnigan XCalibur 

2.7.0.20 or 2.2 SP1.48). Correlation coefficients were calculated with the same software.

All data are reported in parent equivalents, and the individual measured residues of imidacloprid, 

5-hydroxy imidacloprid, and imidacloprid olefin are summed to give a total imidacloprid residue.

The methods for determining imidacloprid, 5-hydroxy imidacloprid, and imidacloprid olefin residues 

in/on tomato leaves and pollen were 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 from fortified samples were measured 

with each set of samples to verify method performance.

5F. QUALITY ASSURANCE RESULTS

The responses of the LC/HRMS and LC/MS/MS systems to imidacloprid, 5-hydroxy imidacloprid, and 

imidacloprid olefin were linear in solvent over the range of 0.00012 to 0.040 ppm (0.0006 to 0.200 ppm 

sample equivalent). The coefficients of determination were >0.99. The response data are located in 

Appendix 4.

Control interferences for tomato matrices are discussed in this paragraph; no total imidacloprid residue 

was calculated for the UTC samples, so the levels of imidacloprid as an individual analyte are described. 

Imidacloprid (parent) residues in UTC tomato pollen ranged from below the analyte LOD to 0.060 ppm 
MRID 49665201 CDPR IMI Soil and Foliar Tomato Study

14

(trial NT018-13ZA). Imidacloprid residues in UTC tomato leaves ranged from below the analyte LOD to 

0.031 ppm (trial NT017-13ZB).

The recovery data for imidacloprid (parent), 5-hydroxy imidacloprid, and imidacloprid olefin residues are 

summarized in Table 5.

All recoveries were corrected for any interferences in corresponding controls. The overall means of the 

recoveries for each matrix at each fortification level were within the acceptable range of 70 to 120%, 

and the standard deviation values were below 20%. The analytical data summaries are located in 

Appendix 4.

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 a 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 analyte 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 deviation of recovery measurements at the LOQ by t0.99 [where t0.99 is the 

one-tailed t-statistic at the 99% confidence level for the number of replicates (n)].8 The LOD for the total 

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

particular matrix.

Table 2. Limits of quantification and detection for imidacloprid and metabolites*.

*From page 11 of the study report.

6. RESULTS:

6.A. COMPARISON OF CONCENTRATIONS MEASURED FOR PARENT AND DEGRADATES

Comparison of the relative concentrations measured for parent imidacloprid and degradation products 

in pollen and leaves are presented in Table 7 and Table 8. The LOD of values for pollen were very low 

ranging from 0.3 ppb to 0.5 ppb. The LOD for leaves ranged from 0.7 to 2.2 ppb. Data reported as below 

the LOD were assigned one-half the LOD value. Comparison of the contribution of each chemical to the 

total residue indicates that parent imidacloprid represented the majority of the total residue measured 

in each plant part. For pollen, parent imidacloprid comprised 90% or greater of the total residue for the 

first three sampling intervals and was at 88% at the last sampling interval. For leaves, parent 

imidacloprid comprised 95% of the total residue for the first three sampling intervals and was at 90% for 

the last sampling interval. Since the degradation products comprised a small portion of the measured 

residue and since they are considered as toxic as parent imidacloprid, the following discussions will 

focus on comparing total imidacloprid residue measured in plant tissues.
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6.B. MAGNITUDE OF RESIDUES IN BEE-RELEVANT MATRICES 

Figure 1 explains the statistical aspects relayed in the Box-and-Whisker plots used to compare the 

distribution of concentrations calculated for comparison of total imidacloprid residue at each sampling 

interval. For each data set analyzed, the box graphic presents values for the mean, median, minimum, 

maximum, and 25th and 75th percentiles. The LOD of values were very low ranging from 0.3 ppb to 

2.2 ppb so data reported as below the LOD were assigned one-half the LOD value.

Pollen. Comparison of overall statistics for total imidacloprid residue indicated much greater 

concentrations in all plant parts at the third sampling interval than at the other three sampling intervals 

(Figure 2). The soil application occurred at planting. Two samplings were conducted at 14 day intervals 

after the soil application and before two foliar applications. The first sampling occurred at a mean of 

48 days after the soil application with a range of values from 31 to 65 days. The second sampling interval 

that was also made prior to foliar applications occurred at a mean of 62 days after the soil application 

with a range of 45 to 77 days. Mean total imidacloprid residues in pollen, which is relevant to potential 

bee exposure, was 66 and 39 ppb for sampling intervals 1 and 2, respectively (Table 7). After the second 

sampling interval plants received two additional foliar applications at approximately 5 day intervals. 

Concentrations measured at the third sampling interval that occurred around 6 days after the second 

foliar application increased nearly tenfold to a mean of 493 ppb with the 90th percentile value at 

1,003 ppb. The fourth and final sampling interval occurred around 19 days after the second foliar 

application where mean total imidacloprid residue concentration were found to drop back down to 

88 ppb. 

6.C. MAGNITUDE OF RESIDUES IN LEAVES

For leaves the same pattern was measured as for pollen where mean total imidacloprid values were 

163, 143, 1527, and 131 ppb for intervals 1, 2, 3, and 4, respectively (Table 8). The tenfold increase at 

the third sampling interval indicated a strong relationship between residues measured in leaves and 

their effect on levels measured in pollen. The sharp decrease in concentration between intervals 3 and 4 

does not appear to be due to wash-off from rainfall or irrigation because drench/drip irrigation was 

indicated at each site and there was essentially no recorded rainfall during the interval between foliar 

applications and sampling of plant tissues.

6.D. SITE SPECIFIC TRENDS

Temporal patterns in residue concentration for each site are depicted in Figure 3 and Figure 4 for pollen 

and leaves, respectively. For pollen data, three sites lacked data for sampling interval 3. Based on the 

pattern noted in section 6.B, this is obviously an important interval so graphs are not presented for sites 

where data was missing for this interval. Data were also not available for sampling interval 2 at the San 

Joaquin and Kerman sites and for interval 1 at the San Luis Obispo site, but they are presented because 

they have data for interval 3 and conformed to the noted trend. The general pattern of mean 

concentrations rising nearly tenfold at the third sampling interval was observed at all sites (Figure 3). A 

sharp decline in concentration between intervals 3 and 4 was also predominant except for the San Luis 

Obispo site where there was only a slight decrease at interval 4.

For leaves, a steep rise at the third sampling interval was reflected at 8 of the 13 curves (Figure 4). 

Curves not reflective of the predominant pattern were indicated at 2 sites (Sanger 1 2014 and Fresno 

2013). Pollen data for these two sites do indicate a significant rise in concentration at the third sampling 

interval. The lack of a similar pattern between leaves and pollen for these two sites indicate a large 

variability in distribution of concentration in leaf tissue. This might be due to variability in application

methodology.
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6.E. Potential Carry-over of Residues

The site specific curves provide comparison for levels measured between 2013 and 2014 for only one 

site, the Sanger site, for pollen and at 4 sites, the Sanger, Porterville, and Fresno sites for leaves 

(Figure 3 and Figure 4). For leaves the values in 2013 are either equal to or greater than the values 

measured in 2014. For pollen the values are similar between the two years. Although the data are 

sparse there is no indication of a carry-over effect of residues between each year.

6.F. LEAF AND NECTAR CONCENTRATION IN RELATION TO SOIL TYPE

Originally, the proposed study design suggested sampling sites located in coarse, medium, and finetextured soils with three replicates assigned to each soil type. The reported soils in this study were 

biased towards coarse soils where, in 2013 two sites were located in coarse-textured soil, one in a 

medium-textured soil and one in the fine-textured category. In 2014, three were located in the finetextured category, one site in medium-textured soil, and five sites in the coarse-textured category. In 

Figure 5 the concentration of total imidacloprid residue in pollen is plotted in relation to levels 

measured in corresponding leaf samples. Data for both years are plotted with data for interval 1 

indicated as black markers, interval 2 as red markers, interval 3 as blue markers, and interval 4 as orange 

markers. Soil texture categories are represented with circles indicating coarse-textured soil, squares for 

medium-texture soil, and triangles for fine-textured soil. Levels measured in pollen from fine-textured 

soil sites approximate levels measured in coarse-textured soils, especially for sampling interval 3. 

Although more representative sampling of the soil groups is needed to provide a definitive relationship 

between method of pesticide application and concentration in plant tissue due to soil type, data at 

interval 3 provide an initial indication that foliar applications greatly increased levels in all plants parts 

irrespective of soil type.
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Table 7. Magnitude of imidacloprid and related metabolites in tomato pollen (ppb).

Interval 1 Interval 2 Interval 3 Interval 4

Olefin 5-OH IMI Total Olefin 5-OH IMI Total Olefin 5-OH IMI Total Olefin 5-OH IMI Total

N 12 12 12 12 10 10 10 10 10 10 10 10 13 13 13 13

Mean 1.1 2.7 62.1 66 0.4 1.5 37.1 39 6.0 22.5 464.3 492.9 1.8 7.0 78.7 88

SD 1.4 2.7 54.0 58.0 0.4 1.2 29.5 30.8 1.8 12.2 291.8 302.7 1.6 10.1 75.9 86.0

CV (%) 127% 103% 87% 88% 107% 94% 80% 79% 31% 54% 63% 61% 86% 144% 96% 99%

Min. 0.2 0.3 6.6 7.0 0.2 0.3 2.6 3.0 3.0 9.7 232.9 249.1 0.2 1.0 21.8 22.9

Median 0.5 1.4 38.6 40.9 0.2 1.2 29.4 30.8 6.4 16.8 364.8 387.1 0.9 4.4 60.6 68.4

75th 1.7 4.3 102.3 108.3 0.4 2.1 48.2 51.6 7.9 30.2 426.1 458.9 3.6 6.9 79.1 87.3

90th 2.4 6.6 121.9 130.8 1.0 4.0 83.4 87.6 8.0 40.0 955.9 1003 3.9 9.7 119.6 132.9

Max. 4.6 8.7 185.1 198.4 1.4 4.8 103.3 106.6 8.1 49.3 1212.3 1268.4 4.4 39.4 312.2 353.9

% of 

Total

1.7% 4.1% 94.2% 0.9% 3.8% 95.1% 1.2% 4.6% 94.2% 2.1% 8.0% 89.8%

NOTES: IMI= imidacloprid, olefin = imidacloprid olefin, 5-OH = 5 hydroxy imidacloprid, Total = sum of IMI, olefin and 5-OH (in bold). SD=standard deviation, CV = 

coefficient of variation.

Table 8. Magnitude of imidacloprid and related metabolites in tomato leaves (ppb).

Interval 1 Interval 2 Interval 3 Interval 4

Olefin 5-OH IMI Total Olefin 5-OH IMI Total Olefin 5-OH IMI Total Olefin 5-OH IMI Total

N 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13

Mean 7.2 8.1 147.6 163 6.2 5.7 131.1 143 38.1 71.0 1417.5 1527 7.2 8.6 115.1 131

SD 7.0 11.3 148.6 165.7 4.6 5.3 100.2 109.4 21.8 46.8 1213.3 1276.1 4.2 5.9 86.8 95.8

CV (%) 97% 141% 101% 102% 74% 92% 76% 76% 57% 66% 86% 84% 58% 68% 75% 73%

Min. 0.5 0.4 1.7 2.5 0.8 0.4 18.6 20.7 7.6 12.3 221.9 241.8 2.3 1.7 39.1 43.1

Median 4.5 4.4 111.5 121.1 6.3 3.4 102.2 114.6 29.6 56.2 863.6 942.8 6.2 7.4 67.5 82.3

75th 9.6 6.3 159.2 173.5 9.0 9.0 231.9 253.7 54.0 107.7 2794.2 2968.2 9.5 11.3 129.1 150.0

90th 16.4 26.5 388.1 445.8 13.3 13.3 266.4 293.4 69.2 121.3 3311.5 3502.3 9.7 16.3 268.6 292.1

Max. 24.7 38.3 517.2 568.4 13.5 16.5 284.0 306.6 78.0 163.6 3348.9 3566.5 18.5 22.0 324.7 365.2

% of 

Total

4.4% 5.0% 90.7% 4.3% 4.0% 91.6% 2.5% 4.7% 92.8% 5.5% 6.6% 87.9%

NOTES: IMI= imidacloprid, olefin = imidacloprid olefin, 5-OH = 5 hydroxy imidacloprid, Total = sum of IMI, olefin and 5-OH (in bold). SD=standard deviation, CV = 

coefficient of variation.
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7. STUDY STRENGTHS, LIMITATIONS AND CONCLUSIONS

The data from this study provide an expected distribution of the concentration of imidacloprid residues 

that bees are exposed to in pollen in tomato flowers grown under actual agronomic practices in 

California. Relating concentrations measured in flower parts to bee health is possible by comparing the 

concentrations measured in bee relevant plant parts to target values that define acute or chronic 

exposure scenarios. The data set is incomplete as the year two results from five trials have not been 

reported yet. Based on the data received, results would represent a minimal exposure assessment to 

foliar applications because samples were not taken during the period of foliar application. Therefore, 

there is some uncertainty with respect as to how reflective the values obtained at the four sampling 

intervals represent maximum exposure scenarios.

In the context of documenting the magnitude of imidacloprid residues in bee-related matrices of 

tomato, the following strengths are observed with this study. 

1. Data provide quantitative values of total imidacloprid residues expected in pollen, and leaves of 

tomato plants grown under California conditions.

2. Measurements were taken at four time intervals in an attempt to quantify levels expected in 

plant tissues: First and second intervals reflected concentrations following a period of time after 

a soil application at planting, and third and fourth intervals reflected concentrations after the 

final foliar application.

Limitations noted in this study include:

1. The study did not follow the residue data protocol calling for three replicates each in fine, 

medium and coarse soils resulting in uncertainty in regards to the effects of soil type on 

imidacloprid uptake in tomato. 

2. The values most likely reflect a minimal exposure because bee relevant tissue was not sampled 

during the period of foliar application.

3. Data were available for two years at only one site for pollen and four sites for leaf data. Thus, 

data to determine whether or not carry-over occurred was not maximal. 

4. Data were missing for pollen sampling at interval 3 at three sites. Highest concentrations were 

measured at this sampling interval so characterization of the distribution for the third sampling 

interval across all sites is incomplete.

5. Data are inadequate to compare the residues among coarse, medium, and fine textured soil 

types because data from coarse soils was disproportionately represented compared to the 

medium and fine soil types.

Overall, considering the strengths and limitations of this study, the following conclusions can be drawn:

1. At approximately 48 days after soil application of approximately 0.38 lb ai/A maximum 

concentration of total imidacloprid residue was 198 ppb in pollen. 

2. For samples taken approximately six days after two foliar applications of approximately 0.068 lb 

ai/A, maximum total imidacloprid residue was 1,268 ppb in pollen. 

3. Mean total imidacloprid residue for samples taken 48 days after the soil application was 66 ppb 

in pollen.

4. Mean total imidacloprid residue was 493 ppb in pollen when sampled 6 days after the second 

foliar application.

5. For the limited data available, there was no evidence of year to year carryover.

6. Generally, residues were highest when sampling occurred following six days after the second

foliar application.
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8. STUDY VALIDITY/CLASSIFICATION

The data from this study provide an expected distribution of the concentration of imidacloprid residues 

that bees are exposed to in pollen of tomato plants grown under actual agronomic practices in 

California. Relating concentrations measured in flower parts to bee health is possible by comparing the 

concentrations measured in bee relevant plant parts to target values that define acute or chronic 

exposure scenarios. These data, however, would represent a minimal exposure assessment to foliar 

applications because samples were not taken during the period of foliar application. Therefore, there is 

uncertainty with respect as to how reflective the values obtained at the four sampling intervals

represent maximum exposure scenarios. The study is considered scientifically sound and useful for risk 

assessment purposes. The study is classified as ACCEPTABLE for quantitative use in risk assessment

9. REFERENCES

1. Brungardt, J. 2010. An Analytical Method for the Determination of Residues of Imidacloprid and its 

Metabolites Imidacloprid Olefin and 5-Hydroxy Imidacloprid in Bee Relevant Matrices Using LC/MS/MS. 

Bayer Method No. NT-005-P10-01.

2. Miller, A. 2014. An Analytical Method for the Determination of Residues of Imidacloprid and its 

Metabolites Imidacloprid Olefin and 5-Hydroxy Imidacloprid in Bee Relevant Matrices Using LC/MS/MS. 

Bayer CropScience Report Number: NT-006-A13-01.

3. Office of Pesticide Programs, US EPA. 2000. Assigning values to nondetected/nonquantified pesticide 

residues in human health food exposure assessments. EPA Docket #OPP-00570A.
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Figure 1. Explanation of statistical meaning of the Box-and-Whisker plots.

Maximum Observation

Minimum Observation

Median Value (50%)

Mean Value 

25% Quartile

75% Quartile
MRID 49665201 CDPR IMI Soil and Foliar Tomato Study

Page 21 of 24

Figure 2. Relative concentration of total imidacloprid residues measured in tomato (A) pollen and (B) 

leaves compared between sampling intervals. Data were averaged over all sites.

A. Pollen B. Leaves

Interval: 1 2 3 4 Interval: 1 2 3 4
MRID 49665201 CDPR IMI Soil and Foliar Tomato Study

Page 22 of 24

Figure 3. Trend in total imidacloprid residue measured in pollen at each site. Within each panel markers 

denote the site, for example Sanger site 1 is solid circles and Sanger site 2 are open squares. Black 

dashed lines are data collected in 2013 and green solid lines are data collected in 2014. Note the 

difference in scale for Fresno and Guadalupe graphs.

Total Imidacloprid Residue (ppb)

Days After Imidacloprid Soil Application

0

100

200

300

400

500 Sanger1 - 2013

Sanger1 - 2014

Sanger2 - 2014

0

100

200

300

400

500

20 30 40 50 60 70 80 90 100 110

San Luis Obispo - 2014

San Joaquin - 2014

Kerman - 2014

0

100

200

300

400

500 Porterville1 - 2014

Porterville2 - 2014

Specific Site Information:

Sanger1=NT018-13ZA

Sanger2=NT042-13ZA

Fresno=NT013-13ZA

Guadalupe=NT017-13ZB

Specific Site Information:

Porterville1=NT010-13ZA

Porterville2=NT016-13ZA

San Luis Obispo=NT039-13ZA

San Joaquin=NT040-13ZA

Kerman=NT041-13ZA

0

500

1000

1500

20 30 40 50 60 70 80 90 100 110

Fresno - 2013

Guadalupe - 2014
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Figure 4. Trend in total imidacloprid residue measured in leaf tissue at each site. Within each panel 

markers denote the site, for example Sanger site 1 is solid circles and Sanger site 2 are open squares. 

Black dashed lines are data collected in 2013 and green lines are data collected in 2014. Note the 

differences in scale between the graphs.

Total Imidacloprid Residue (ppb)

Days After Imidacloprid Soil Application

0

1000

2000

3000

4000

Sanger1 - 2013

Sanger1 - 2014

Sanger2 - 2014

0

500

1000

1500

20 30 40 50 60 70 80 90 100 110

Fresno - 2013

Fresno - 2014

Guadalupe - 2014

0

500

1000

1500

20 30 40 50 60 70 80 90 100 110

San Luis Obispo - 2014

San Joaquin - 2014

Kerman - 2014

0

1000

2000

3000

4000 Porterville1 - 2013

Porterville1 - 2014

Porterville2 - 2013

Porterville2 - 2014

Specific Site Information:

Sanger1=NT018-13ZA

Sanger2=NT042-13ZA

Fresno=NT013-13ZA

Guadalupe=NT017-13ZB

Specific Site Information:

Porterville1=NT010-13ZA

Porterville2=NT016-13ZA

San Luis Obispo=NT039-13ZA

San Joaquin=NT040-13ZA

Kerman=NT041-13ZA
MRID 49665201 CDPR IMI Soil and Foliar Tomato Study

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Figure 5. Relationship between concentration of total imidacloprid residues measured in tomato leaves 

and pollen parsed out by soil type. Numbers after the texture category indicate data for interval 1, 2, 3, 

or 4 where black markers are from sampling interval 1, red markers from interval 2, and blue markers 

from interval 3. Circles are coarse-texture soils, squares are medium-textured soils, and triangles are 

fine-textured soils. 

0.00

500.00

1000.00

1500.00

0 500 1000 1500 2000 2500 3000 3500

Coarse -1 Medium -1 Fine -1

Coarse -2 Medium -2 Fine -2

Coarse -3 Medium -3 Fine -3

Coarse -4 Medium -4 Fine -4

Pollen Total Imidacloprid Residue (ppb)

Leaf Total Imidacloprid Concentration