maximum residue levels with decline for three insecticides on … · 2014. 11. 19. · richland, wa...

Washington State University FEQL Study No. 0313

Food and Environmental Quality Laboratory Page 1 of 62

Maximum Residue Levels with Decline for Three Insecticides on Highbush

Blueberry after Mistigation and Airblast Treatments

Authors

Jane LePage and Vince Hebert

Testing Facility

Food and Environmental Quality Laboratory

Department of Entomology

Washington State University

2710 Crimson Way

Richland, WA 99354-1671

FEQL Study No.: 0313

Principle Field Investigators

Lynell K. Tanigoshi1, Beverly S. Gerdeman

1 and Wei Yang

2

1 Washington State University Mount Vernon Northwestern Washington Research &

Extension Center (WSU-NWREC), 16650 State Route 536 Mount Vernon, WA 98273 2

North Willamette Research and Extension Center (OSU-NWREC), 15210 NE Miley Rd.,

Aurora, OR 97002

Collaborators

Steve Erikson, CEO, Pan-American Berry Growers, Salem OR

Study Timetable

Study Initiation Date: 7/15/13

Experimental Termination Date: 2/20/14

Report Date

4/20/2014



Certification

The undersigned hereby declares that this study was performed according to the procedures

described herein, and that this report provides a true and accurate record of the results obtained.

Associate Research Scientist: Date: 04/17/2014

Dr. Vince Hebert, Food and Environmental Quality Laboratory

Washington State University, Tri-City Campus, Richland WA

Analytical work performed by:

Jane LePage Research Analyst

Archives (Location of Raw Data)

The original raw data, correspondence logs, and all relevant information for the study titled:

“Maximum Residue Levels with Decline for Insecticides on Highbush Blueberry after

Mistigation and Airblast Treatments,” FEQL project number 0313, along with certified originals

of the signed analytical summary report will be maintained by the testing facility for a period of

3 years. Exact copies of the analytical summary report and relevant information for the

construction of this study can be made available to the principle field investigators or

collaborators on request.

Associate Research Scientist Dr. Vincent Hebert

Testing Facility: Food and Environmental Quality Laboratory

Washington State University

2710 Crimson Way

Richland, WA 99354-1671



Table of Contents

Page

Certification 2

Archives (location of raw data) 2

Table of Contents 3

Executive Summary 4

Analytical Summary 8

I. Objective/Introduction 8 II. Sample Inventory & History 8

III. Standard Preparation 16

IV. Analytical Procedure 17

A. Residue Method 17 B. Analytical Limits 18 C. Instrumentation 18 D. Quantitation 19 E. Interferences 20 F. Confirmatory Techniques 21 G. Time Required for Analysis 21 H. Modifications or Potential Problems 21

V. Results 22

A. Method Validation and Recovery Results 22 B. Storage Stability 24 C. Residue Results 24

Appendix A: Protocol 35

Appendix B: Working method 43

Appendix C: Sample Chromatograms 46



Executive Summary

International pesticide maximum residue level (MRL) issues will remain a major concern

for blueberry growers seeking effective season-long Spotted Wing Drosophila (SWD)

control. Although many US and foreign agricultural agencies are working towards global

MRL harmonization, developing an effective resistance management spray program remains

a challenge to our PNW growers, especially when exporting to the Pacific Rim where vastly

different MRL requirements exist. Until there is more uniformity in MRL setting,

understanding season-long insecticide field decline and appropriately planning spray

programs on a customer-by-customer basis for now may be the best insurance to avert crop

rejection concerns.

To better understand season-long field decline, from July through late September 2013, a

weekly insecticide application program was performed on late-season ripening Aurora

highbush blueberries as part of a program to control SWD at Pan-American Berry Growers

(PBG), Salem, OR (see Figure 1). During the SWD spray season, multiple applications of

Malathion AquaTM

, Mustang Maxx™

, and a single late season DanitolTM

application were

conducted at commercial rates (Table 1).

Analytical Summary Report

Figure 1: Plot locations for Salem Oregon 2013 blueberry decline study



Table 1: Salem OR SWD Spray Program and Sampling Events

Treatment Insecticide Application Interval Sampling

Week 1 Malathion Aqua (1.25 pts 100 GPA; 1 day PHI**)

-1 through 14 DAT*

Week 2 Mustang Maxx (4.0 fluid oz 100 GPA ;1 Day PHI)

-1 through 14 DAT

Week 3 Malathion Aqua (1.25 pts 100 GPA; 1 day PHI)

-1 through 14 DAT

Week 4 Mustang Maxx (4.0 fluid oz 100 GPA ;1 Day PHI)

-1 through 14 DAT

Last week Danitol (16 fluid oz 100 GPA; 3 Day PHI) ***

-1 through 24 DAT

* DAT = Days after treatment

** PHI = Preharvest Interval

*** Because of the lack of a label use for mistigation, an airblast application was

solely evaluated for Danitol decline

This insecticide decline study examined pesticide residues on marketable fruit after

pesticide application by two commercial application techniques being used by the grower,

chemigation using misters (mistigation; M) and airblast (AB).

Malathion and Mustang Maxx M and AB chemical applications were conducted on the

same day to compare if there are residue decline differences due to application method.

Marketable berries were sampled before chemical application (-1), and at 0, 1, 3, 5, 7, 10,

and 14 days after treatment (DAT; see Table 1). There is no label allowed use for mistigation

using Danitol and here only AB residue decline was evaluated. Since we anticipated that

Danitol could decline at a slower rate, we continued field sampling through 24 DAT. Two

composited berry samples were collected from each of the above AB and M treatment plots

on the above DATs. A separated control block (C, see Figure 1) did not receive any of the

three insecticide treatments and was sampled similarly to treatment blocks at the above

DATs. After sampling, the composit treatment and control berry samples were stored at the

OSU North Willamette Research and Extension Center (NWREC) USDA IR-4 freezer

facilities until vehicle transport by ACDS refrigerated trucking services to the WSU Food

and Environmental Quality Laboratory (WSU-FEQL) in Richland WA.

Quality Control: When generating residue decline data, it is essential to reliably

demonstrate precision in both field sampling and chemical analysis. To show field sampling

precision, duplicate composited berry field samples were taken from 20 randomly selected

highbushes in each of the M, AB, and C treatment locations on each sampling interval day.

To demonstrate precision in chemical analysis, fortified control blueberry samples were

prepared with each analytical set. For this study, over 129 quality control results were

calculated to support the 148 multi-residue malathion Aqua, Mustang Maxx, and Danitol

decline measures reported in this seasonal decline study. We also followed season-long field



M and AB applications for Imidan (phosmet) with appropriate quality control to evaluate if

berry residues approached Pacific Rim MRL values.

MRL and Field Decline Results:

Malathion: Figure 2, page 26 shows field residues before and after malathion applications

occurring in late July and early August 2013. The reproducibility among the duplicate

composited berry sample data points at each interval date for M (in green) and AB (in blue)

demonstrates a high degree of uniformity when gathering berries for our residue

determinations. Thirty-nine laboratory fortifications (spikes) resulted in an overall average

recovery of 102 +

8%. The high precision in both field sampling and laboratory analysis

indicate actual residues on berries in the field over the July 28 through mid-August study

decline period.

The fairly rapid residue decline for malathion as well as other organophosphorus

insecticides in field crops has been understood for quite some time. Our decline results are

also very similar to a recent decline study conducted at similar rates on sweet cherries

(Haviland and Beers 2012). For malathion, the allowable maximum use is 5 pints per acre

per year where up to 2.5 pints can be applied for any one application. Although this is data

from a single field study, it is reasonable to state that 4 seasonal blueberry applications at

1.25 pints/acre will not trigger MRLs in the US (8 ppm), or Korea (10 ppm). However, other

Pacific Rim MRLs may be exceeded. Japan’s current MRL is 0.5 ppm where Taiwan’s is

more conservatively set at 0.1 ppm. When developing a harvest program for malathion, the

grower may choose to delay picking 3-5 days later than the allowed 1 day PHI to better

insure that field residues will not trigger a Japan MRL concern. However, this data is only

from one season and risks of exceeding the MRL can still exist.

Mustang Maxx: Figure 3, page 26 shows field residues before and after applications in early

to late August 2013. The good reproducibility among the duplicate composited berry sample

data points for M and AB applications at each interval date and consistent recovery among

35 fortified samples (89 +

15%) indicate that testing laboratories should find similar

concentrations in marketable berries. Mustang Maxx berry residues (as zeta-cypermethrin)

were found at much lower than US (MRL = 8 ppm) and Pacific Rim MRLs from Korea and

Japan (respectively 10 and 0.5 ppm). It is important to note that Taiwan does not currently

provide an MRL for the active ingredient zeta-cypermethrin in Mustang Maxx. As such, any

detected residue may trigger a trade barrier concern. The appreciably slower rate of residue

decline when compared to organophosphorus insecticides is typical of pyrethroid insecticides

and again similar to recent cherry decline work by Haviland and Beers (2012). We did

observe a consistently higher level of Mustang Maxx residues after the second air blast

application. Although results from one-season decline study make it difficult to precisely

predict residues that may occur under differing climatic and growing conditions, it is

reasonable to state that growers should be wary of making too many consecutive applications

of this substance if planning to export to counties such as Japan.

Danitol: This substance can currently be only applied twice in any one growing season and

was used in late August as a clean-up application. Because of its longer-lasting efficacy on

SWD (Lynell Tanigoshi, personal communication), we anticipated that this pyrethroid



chemistry would decline slowly in the field as is evident in Figure 4 on page 27. Decline

on/in blueberry was similar to the recent decline study conducted at a similar rate on sweet

cherries by Haviland and Beers (2012). Although the Danitol data again represents a single

PNW field study, it is reasonable to anticipate that Danitol applied at the commercial rate of

16 fluid oz per acre should not trigger MRLs in the US (8 ppm), Japan (5 ppm), or Taiwan (3

ppm). However, Korea MRLs may likely be exceeded well after the 3 day PHI.

Fenpropathrin, the active ingredient in Danitol appears to be a longer lasting pyrethroid. The

grower may consider using this substance as a start and late season finish SWD treatment

since current label use of this material (as of 2013) only allows two seasonal applications.

Cumulative Season-long Field Residues: Malathion, Mustang Maxx, and Danitol blueberry

residues were measured in the field on 32 separate sampling events from late July through

mid-September. Residues of Imidan (phosmet) were also assessed over the 48 day spray

period. Figure 5, page 27 provides the residue data for the 4 compounds. This profile

suggests that cumulative residues over the growing season may be effective in controlling

SWD field populations thus reducing the need for weekly applications. As a result, the

grower should consider season-long residual pesticide field concentrations together with

scouting as part of the SWD spray management program.

The results from this one-year seasonal decline study suggests

• Pesticide residues for the three evaluated active ingredients at commercial application rates can sometimes exceed MRLs for certain Pacific Rim exporting markets.

• Blueberry field decline is similar for these active ingredients to other PNW small fruits.

This study also suggests:

• For certain Pacific Rim markets, delay harvesting longer than the label specified PHI. • Consider season-long residual pesticide field concentrations as part of the SWD spray

management program.

• Start and finish the spray season with a longer-lasting active ingredient.

Reference:

Haviland D. Beers E. 2012 chemical control programs for Drosophila suzukii that comply

with international limitations on pesticide residues for exported sweet cherries. J. Integ. Pest

Mngmt. 3(2): 2012; DOI: http://dx.doi.org/10.1603/IPM11034

http://dx.doi.org/10.1603/IPM11034



Analytical Summary

I. Objective/Introduction

Pesticides were applied weekly on high bush blueberries (Vaccinium corymbosum) at Pan-

American Berry Growers (PBG), Salem, OR as part of a program to control spotted wing

drosophila, Drosophila suzukii (Matsumura; SWD). This study specifically monitored the

pesticide residue on marketable fruit after pesticide application.

From July through September, 2013, malathion (Malathion Aqua®, 1.25 pts 100 gallons per

acre (GPA); 1 day pre-harvest interval (PHI)), zeta-cypermethrin (Mustang Maxx™

; 4.0 fluid oz

100 GPA; 1 day PHI) were applied at the maximum allowed grower use rates using chemigation

(mistigation; M) and air blast (AB) spray methods. Applications by these two methods occurred

on the same day; marketable berries were sampled at -1, 0, 1, 3, 5, 7, 10, and 14 days after

treatment (DAT) to evaluate decline of pesticide residues. In addition, in September Danitol®

(active ingredient: fenpropathrin) was applied by airblast to that treatment plot. Berries were

sampled for fenpropathrin residue decline at -1, 0, 1, 2, 4, 8, 12, 15, and 24 DAT. Phosmet was

also monitored in field samples as a secondary pesticide of interest.

The generated residue information in tandem with WSU-NWREC SWD bioassay efficacy

foliage data (Project Number 0313-B) provides growers with a regional reference tool to decide

on an appropriate harvest day that controls crop injury while reducing uncertainty of exceeding

international maximum residue levels (MRLs).

II. Sample Inventory & History

A separate control block of Aurora high bush blueberries was designated at the start of this

study (see Figure 1). This plot received no malathion, zeta-cypermethrin or fenpropathrin

pesticide applications during the study. Control blueberries were collected from the control block

on each sampling day. At the treatment blocks, berries were picked at low, mid, and high cluster

locations from at least 20 randomly selected high bush blueberry plants for a composite sample

which represented commercial harvesting practices. Duplicate treatment samples were collected

on each sampling day.

Samples were labeled according to the protocol (FEQL 0313, see Appendix A) with M, AB,

or C to designate treatment block (mistigation, airblast or control), the sampling date and T or

TD for treatment or treatment duplicate.

The control and treated blueberry samples were stored in freezers at PBG or the North

Willamette Research and Extension Center (OSU-NWREC) until transport to the WSU-Food

and Environmental Quality Laboratory (FEQL). Samples were shipped by ACDS freezer truck

on 8/12/13, 9/13/13 and 10/15/13. On arrival at the laboratory all samples were placed in a

freezer (ID Dasher) until processing and analysis. Samples were processed by pulverizing frozen

berries with dry ice using Robot Coupe Processor. The entire sample was processed and returned

to the freezer. Table 2 provides the sample inventory and dates for subsequent handling of the

samples in frozen storage at FEQL. The sample names represent the name on the sample upon

arrival appended with the FEQL project number, 0313.



Table 2 FEQL Blueberry Sample Inventory

Sample IDs Sampling

Date

Treatment Status

Days after Treatment

Arrival at FEQL

Date processed

Weighed for extraction

Date of extraction

Days in frozen storage

Set

0313-C-072713 7/27/2013 M(-1) 8/13/2013 8/13/2013 9/12/2013 9/23/2013 58 set2re

0313-M-072713-T 7/27/2013 M(-1) 8/13/2013 8/15/2013 9/12/2013 9/23/2013 58 0313-M-072713-TD 7/27/2013 M(-1) 8/13/2013 8/15/2013 9/12/2013 9/23/2013 58 0313-AB-072713-T 7/27/2013 M(-1) 8/13/2013 8/15/2013 9/12/2013 9/23/2013 58 0313-AB-072713-TD 7/27/2013 M(-1) 8/13/2013 8/15/2013 9/12/2013 9/23/2013 58 0313-C-072813 7/28/2013 M0 8/13/2013 8/13/2013 10/7/2013 10/7/2013 71 set11re

0313-M-072813-T 7/28/2013 M0 9/14/2013 10/2/2013 10/7/2013 10/7/2013 71 0313-M-072813-TD 7/28/2013 M0 9/14/2013 10/2/2013 10/7/2013 10/7/2013 71 0313-AB-072813-T 7/28/2013 M0 9/14/2013 10/2/2013 10/7/2013 10/7/2013 71 0313-AB-072813-TD 7/28/2013 M0 9/14/2013 10/2/2013 10/7/2013 10/7/2013 71 0313-C-072913 7/29/2013 M1 8/13/2013 8/13/2013 10/11/2013 10/11/2013 74 set14

0313-M-072913-T 7/29/2013 M1 8/13/2013 8/15/2013 10/11/2013 10/11/2013 74 0313-M-072913-TD 7/29/2013 M1 8/13/2013 8/15/2013 10/11/2013 10/11/2013 74 0313-AB-072913-T 7/29/2013 M1 9/14/2013 10/10/2013 10/11/2013 10/11/2013 74 0313-AB-072913-TD 7/29/2013 M1 9/14/2013 10/10/2013 10/11/2013 10/11/2013 74 0313-C-073013 7/30/2013 M2 8/13/2013 8/14/2013 9/12/2013 9/23/2013 55 set3RE

0313-M-073013-T 7/30/2013 M2 8/13/2013 8/19/2013 9/12/2013 9/23/2013 55 0313-M-073013-TD 7/30/2013 M2 8/13/2013 8/19/2013 9/12/2013 9/23/2013 55 0313-AB-073013-T 7/30/2013 M2 8/13/2013 8/19/2013 9/12/2013 9/23/2013 55 0313-AB-073013-TD 7/30/2013 M2 8/13/2013 8/19/2013 9/12/2013 9/23/2013 55 0313-C-073113 7/31/2013 M3 8/13/2013 8/13/2013 9/23/2013 9/24/2013 55 set4RE

0313-M-073113-T 7/31/2013 M3 8/13/2013 8/15/2013 9/23/2013 9/24/2013 55 0313-M-073113-TD 7/31/2013 M3 8/13/2013 8/15/2013 9/23/2013 9/24/2013 55 0313-AB-073113-T 7/31/2013 M3 8/13/2013 8/15/2013 9/23/2013 9/24/2013 55



Sample IDs Sampling

Date

Treatment Status


Arrival at FEQL

Date processed


Date of extraction


Set

0313-AB-073113-TD 7/31/2013 M3 8/13/2013 8/15/2013 9/23/2013 9/24/2013 55 0313-C-080213 8/2/2013 M5 8/13/2013 8/14/2013 9/23/2013 9/24/2013 53 set5RE2

0313-M-080213-T 8/2/2013 M5 8/13/2013 8/19/2013 9/23/2013 9/24/2013 53 0313-M-080213-TD 8/2/2013 M5 8/13/2013 8/19/2013 9/23/2013 9/24/2013 53 0313-AB-080213-T 8/2/2013 M5 8/13/2013 8/19/2013 9/23/2013 9/24/2013 53 0313-AB-080213-TD 8/2/2013 M5 8/13/2013 8/19/2013 9/23/2013 9/24/2013 53 0313-C-080313 8/3/2013 MM(-1) 8/13/2013 8/14/2013 9/23/2013 9/25/2013 53 set6RE

0313-M-080313-T 8/3/2013 MM(-1) 8/13/2013 8/14/2013 9/23/2013 9/25/2013 53 0313-M-080313-TD 8/3/2013 MM(-1) 8/13/2013 8/14/2013 9/23/2013 9/25/2013 53 0313-AB-080313-T 8/3/2013 MM(-1) 8/13/2013 8/14/2013 9/23/2013 9/25/2013 53 0313-AB-080313-TD 8/3/2013 MM(-1) 8/13/2013 8/14/2013 9/23/2013 9/25/2013 53 0313-C-080413 8/4/2013 M7, MM0 8/13/2013 8/14/2013 9/30/2013 9/30/2013 57 set7

0313-M-080413-T 8/4/2013 M7, MM0 8/13/2013 8/19/2013 9/30/2013 9/30/2013 57 0313-M-080413-TD 8/4/2013 M7, MM0 8/13/2013 8/19/2013 9/30/2013 9/30/2013 57 0313-AB-080413-T 8/4/2013 M7, MM0 8/13/2013 8/19/2013 9/30/2013 9/30/2013 57 0313-AB-080413-TD 8/4/2013 M7, MM0 8/13/2013 8/19/2013 9/30/2013 9/30/2013 57 0313-C-080513 8/5/2013 MM1 8/13/2013 8/14/2013 9/30/2013 10/1/2013 57 set8

0313-M-080513-T 8/5/2013 MM1 8/13/2013 8/19/2013 9/30/2013 10/1/2013 57 0313-M-080513-TD 8/5/2013 MM1 8/13/2013 8/19/2013 9/30/2013 10/1/2013 57 0313-AB-080513-T 8/5/2013 MM1 8/13/2013 8/19/2013 9/30/2013 10/1/2013 57 0313-AB-080513-TD 8/5/2013 MM1 8/13/2013 8/19/2013 9/30/2013 10/1/2013 57 0313-C-080713 8/7/2013 M10, MM3 8/13/2013 8/14/2013 9/30/2013 10/1/2013 55 set9

0313-M-080713-T 8/7/2013 M10, MM3 8/13/2013 8/14/2013 9/30/2013 10/1/2013 55 0313-M-080713-TD 8/7/2013 M10, MM3 8/13/2013 8/14/2013 9/30/2013 10/1/2013 55 0313-AB-080713-T 8/7/2013 M10, MM3 8/13/2013 8/14/2013 9/30/2013 10/1/2013 55



Sample IDs Sampling

Date

Treatment Status


Arrival at FEQL

Date processed


Date of extraction


Set

0313-AB-080713-TD 8/7/2013 M10, MM3 8/13/2013 8/14/2013 9/30/2013 10/1/2013 55 0313-C-080913 8/9/2013 MM5 8/13/2013 8/14/2013 9/30/2013 10/1/2013 53 set10

0313-M-080913-T 8/9/2013 MM5 8/13/2013 8/15/2013 9/30/2013 10/1/2013 53 0313-M-080913-TD 8/9/2013 MM5 8/13/2013 8/15/2013 9/30/2013 10/1/2013 53 0313-AB-080913-T 8/9/2013 MM5 8/13/2013 8/15/2013 9/30/2013 10/1/2013 53 0313-AB-080913-TD 8/9/2013 MM5 8/13/2013 8/15/2013 9/30/2013 10/1/2013 53 0313-C-081013 8/10/2013 M(-1) 8/13/2013 8/14/2013 9/11/2013 9/11/2013 32 set1re

0313-M-081013-T 8/10/2013 M(-1) 8/13/2013 8/15/2013 9/11/2013 9/11/2013 32 0313-M-081013-TD 8/10/2013 M(-1) 8/13/2013 8/15/2013 9/11/2013 9/11/2013 32 0313-AB-081013-T 8/10/2013 M(-1) 8/13/2013 8/15/2013 9/11/2013 9/11/2013 32 0313-AB-081013-TD 8/10/2013 M(-1) 8/13/2013 8/15/2013 9/11/2013 9/11/2013 32 0313-C-081113 8/11/2013 M0, MM7 9/14/2013 9/25/2013 10/8/2013 10/8/2013 58 set12

0313-M-081113-T 8/11/2013 M0, MM7 9/14/2013 10/7/2013 10/8/2013 10/8/2013 58 0313-M-081113-TD 8/11/2013 M0, MM7 9/14/2013 10/7/2013 10/8/2013 10/8/2013 58 0313-AB-081113-T 8/11/2013 M0, MM7 9/14/2013 10/7/2013 10/8/2013 10/8/2013 58 0313-AB-081113-TD 8/11/2013 M0, MM7 9/14/2013 10/7/2013 10/8/2013 10/8/2013 58 0313-C-081213 8/12/2013 M1 9/14/2013 10/2/2013 10/8/2013 10/10/2013 59 set13

0313-M-081213-T 8/12/2013 M1 9/14/2013 10/8/2013 10/8/2013 10/10/2013 59 0313-M-081213-TD 8/12/2013 M1 9/14/2013 10/8/2013 10/8/2013 10/10/2013 59 0313-AB-081213-T 8/12/2013 M1 9/14/2013 10/8/2013 10/8/2013 10/10/2013 59 0313-AB-081213-TD 8/12/2013 M1 9/14/2013 10/8/2013 10/8/2013 10/10/2013 59 0313-C-081313 8/13/2013 M2 9/14/2013 9/26/2013 10/15/2013 10/15/2013 63 set16

0313-M-081313-T 8/13/2013 M2 9/14/2013 10/14/2013 10/15/2013 10/15/2013 63 0313-M-081313-TD 8/13/2013 M2 9/14/2013 10/14/2013 10/15/2013 10/15/2013 63 0313-AB-081313-T 8/13/2013 M2 9/14/2013 10/14/2013 10/15/2013 10/15/2013 63



Sample IDs Sampling

Date

Treatment Status


Arrival at FEQL

Date processed


Date of extraction


Set

0313-AB-081313-TD 8/13/2013 M2 9/14/2013 10/14/2013 10/15/2013 10/15/2013 63 0313-C-081413 8/14/2013 M3, MM10 9/14/2013 9/30/2013 10/14/2013 10/14/2013 61 set15

0313-M-081413-T 8/14/2013 M3, MM10 9/14/2013 10/9/2013 10/14/2013 10/14/2013 61 0313-M-081413-TD 8/14/2013 M3, MM10 9/14/2013 10/9/2013 10/14/2013 10/14/2013 61 0313-AB-081413-T 8/14/2013 M3, MM10 9/14/2013 10/10/2013 10/14/2013 10/14/2013 61 0313-AB-081413-TD 8/14/2013 M3, MM10 9/14/2013 10/10/2013 10/14/2013 10/14/2013 61 0313-C-081613 8/16/2013 M5 9/14/2013 9/25/2013 10/16/2013 10/16/2013 61 set17

0313-M-081613-T 8/16/2013 M5 9/14/2013 10/15/2013 10/16/2013 10/16/2013 61 0313-M-081613-TD 8/16/2013 M5 9/14/2013 10/15/2013 10/16/2013 10/16/2013 61 0313-AB-081613-T 8/16/2013 M5 9/14/2013 10/15/2013 10/16/2013 10/16/2013 61 0313-AB-081613-TD 8/16/2013 M5 9/14/2013 10/15/2013 10/16/2013 10/16/2013 61 0313-C-081713 8/17/2013 MM(-1) 9/14/2013 9/30/2013 10/17/2013 10/17/2013 61 set18

0313-M-081713-T 8/17/2013 MM(-1) 9/14/2013 10/16/2013 10/17/2013 10/17/2013 61 0313-M-081713-TD 8/17/2013 MM(-1) 9/14/2013 10/16/2013 10/17/2013 10/17/2013 61 0313-AB-081713-T 8/17/2013 MM(-1) 9/14/2013 10/16/2013 10/17/2013 10/17/2013 61 0313-AB-081713-TD 8/17/2013 MM(-1) 9/14/2013 10/16/2013 10/17/2013 10/17/2013 61

0313-C-081813 8/18/2013 M7, MM14, MM0 9/14/2013 9/30/2013 10/21/2013 10/21/2013 64 set19

0313-M-081813-T 8/18/2013 M7, MM14, MM0 9/14/2013 10/17/2013 10/21/2013 10/21/2013 64

0313-M-081813-TD 8/18/2013 M7, MM14, MM0 9/14/2013 10/17/2013 10/21/2013 10/21/2013 64

0313-AB-081813-T 8/18/2013 M7, MM14, MM0 9/14/2013 10/17/2013 10/21/2013 10/21/2013 64



Sample IDs Sampling

Date

Treatment Status


Arrival at FEQL

Date processed


Date of extraction


Set

0313-AB-081813-TD 8/18/2013 M7, MM14, MM0 9/14/2013 10/17/2013 10/21/2013 10/21/2013 64

0313-C-081913 8/19/2013 MM1 9/14/2013 9/26/2013 10/22/2013 10/22/2013 64 set20

0313-M-081913-T 8/19/2013 MM1 9/14/2013 10/9/2013 10/22/2013 10/22/2013 64 0313-M-081913-TD 8/19/2013 MM1 9/14/2013 10/9/2013 10/22/2013 10/22/2013 64 0313-AB-081913-T 8/19/2013 MM1 9/14/2013 10/9/2013 10/22/2013 10/22/2013 64 0313-AB-081913-TD 8/19/2013 MM1 9/14/2013 10/9/2013 10/22/2013 10/22/2013 64 0313-C-082113 8/21/2013 M10, MM3 9/14/2013 9/30/2013 10/24/2013 10/24/2013 64 set22

0313-M-082113-T 8/21/2013 M10, MM3 9/14/2013 10/23/2013 10/24/2013 10/24/2013 64 0313-M-082113-TD 8/21/2013 M10, MM3 9/14/2013 10/23/2013 10/24/2013 10/24/2013 64 0313-AB-082113-T 8/21/2013 M10, MM3 9/14/2013 10/23/2013 10/24/2013 10/24/2013 64 0313-AB-082113-TD 8/21/2013 M10, MM3 9/14/2013 10/23/2013 10/24/2013 10/24/2013 64 0313-C-082313 8/23/2013 MM5 9/14/2013 9/30/2013 10/28/2013 10/28/2013 66 set23

0313-M-082313-T 8/23/2013 MM5 9/14/2013 10/10/2013 10/28/2013 10/28/2013 66 0313-M-082313-TD 8/23/2013 MM5 9/14/2013 10/10/2013 10/28/2013 10/28/2013 66 0313-AB-082313-T 8/23/2013 MM5 9/14/2013 10/10/2013 10/28/2013 10/28/2013 66 0313-AB-082313-TD 8/23/2013 MM5 9/14/2013 10/10/2013 10/28/2013 10/28/2013 66 0313-C-082413 8/24/2013 D(-1) 9/14/2013 9/25/2013 10/23/2013 10/23/2013 60 set21

0313-M-082413-T 8/24/2013 D(-1) 9/14/2013 10/22/2013 10/23/2013 10/23/2013 60 0313-M-082413-TD 8/24/2013 D(-1) 9/14/2013 10/22/2013 10/23/2013 10/23/2013 60 0313-AB-082413-T 8/24/2013 D(-1) 9/14/2013 10/22/2013 10/23/2013 10/23/2013 60 0313-AB-082413-TD 8/24/2013 D(-1) 9/14/2013 10/22/2013 10/23/2013 10/23/2013 60

0313-C-082513 8/25/2013 M14, MM7, D0 9/14/2013 10/2/2013

10/29/2013 11/5/2013

10/30/2013 11/5/2013

61 67

set24 set 24r for zeta-cypermethrin



Sample IDs Sampling

Date

Treatment Status


Arrival at FEQL

Date processed


Date of extraction


Set

0313-C-083013 8/30/2013 D5 9/14/2013 9/25/2013 10/29/2013 11/5/2013

10/30/2013 11/5/2013

61 67


0313-M-083013-T 8/30/2013 D5 9/14/2013 10/29/2013 10/30/2013 11/5/2013

10/30/2013 11/5/2013

61 67

0313-M-083013-TD 8/30/2013 D5 9/14/2013 10/29/2013 10/30/2013 11/5/2013

10/30/2013 11/5/2013

61 67

0313-AB-083013-T 8/30/2013 D5 9/14/2013 10/29/2013 10/30/2013 11/5/2013

10/30/2013 11/5/2013

61 67

0313-AB-083013-TD 8/30/2013 D5 9/14/2013 10/29/2013

10/30/2013 11/5/2013

10/30/2013 11/5/2013

61 67

0313-C-090113 9/1/2013 D7, MM14 9/14/2013 9/25/2013 10/31/2013 10/31/2013 60 set25

0313-M-090113-T 9/1/2013 D7, MM14 9/14/2013 10/21/2013 10/31/2013 10/31/2013 60 0313-M-090113-TD 9/1/2013 D7, MM14 9/14/2013 10/21/2013 10/31/2013 10/31/2013 60 0313-AB-090113-T-A 9/1/2013 D7, MM14 9/14/2013 10/21/2013 10/31/2013 10/31/2013 60 0313-AB-090113-TD-A 9/1/2013 D7, MM14 9/14/2013 10/21/2013 10/31/2013 10/31/2013 60 0313-AB-090113-T-B 9/1/2013 D0 9/14/2013 10/24/2013 10/31/2013 10/31/2013 60 0313-AB-090113-TD-B 9/1/2013 D0 9/14/2013 10/24/2013 10/31/2013 10/31/2013 60 0313-C-090213 9/2/2013 D1 9/14/2013 10/2/2013 11/5/2013 11/6/2013 65 Set26

0313-AB-090213-T 9/2/2013 D1 9/14/2013 10/30/2013 11/5/2013 11/6/2013 65 0313-AB-090213-TD 9/2/2013 D1 9/14/2013 10/30/2013 11/5/2013 11/6/2013 65 0313-C-090313 9/3/2013 D2 9/14/2013 9/26/2013 11/5/2013 11/6/2013 64 set26

0313-AB-090313-T 9/3/2013 D2 9/14/2013 10/24/2013 11/5/2013 11/6/2013 64 0313-AB-090313-TD 9/3/2013 D2 9/14/2013 10/24/2013 11/5/2013 11/6/2013 64 0313-C-090513 9/5/2013 D4 9/14/2013 10/28/2013 11/7/2013 11/7/2013 63 set27

0313-AB-090513-T 9/5/2013 D4 9/14/2013 10/28/2013 11/7/2013 11/7/2013 63



Sample IDs Sampling

Date

Treatment Status


Arrival at FEQL

Date processed


Date of extraction


Set

0313-AB-090513-TD 9/5/2013 D4 9/14/2013 10/28/2013 11/7/2013 11/7/2013 63 0313-C-090913 9/9/2013 D8 9/14/2013 9/30/2013 11/7/2013 11/7/2013 59 set27

0313-AB-090913-T 9/9/2013 D8 9/14/2013 11/6/2013 11/7/2013 11/7/2013 59 0313-AB-090913-TD 9/9/2013 D8 9/14/2013 11/6/2013 11/7/2013 11/7/2013 59 0313-C-091313 9/13/2013 D12 9/14/2013 9/26/2013 11/12/2013 11/12/2013 60 set28

0313-AB-091313-T 9/13/2013 D12 9/14/2013 10/30/2013 11/12/2013 11/12/2013 60 0313-AB-091313-TD 9/13/2013 D12 9/14/2013 10/30/2013 11/12/2013 11/12/2013 60 0313-C-091613 9/16/2013 D15 10/17/2013 11/7/2013 11/12/2013 11/12/2013 57 set28

0313-AB-091613-T 9/16/2013 D15 10/17/2013 11/5/2013 11/12/2013 11/12/2013 57 0313-AB-091613-TD 9/16/2013 D15 10/17/2013 11/5/2013 11/12/2013 11/12/2013 57 0313-C-092513 9/25/2013 D24 10/17/2013 11/7/2013 11/12/2013 11/12/2013 48 set28

0313-AB-092513-T 9/25/2013 D24 10/17/2013 11/6/2013 11/12/2013 11/12/2013 48 0313-AB-092513-TD 9/25/2013 D24 10/17/2013 11/6/2013 11/12/2013 11/12/2013 48



III. Standard Preparation

Linearity standards in control matrix were prepared with each sample set to compare sample

residues to a linear regression calculated from four standard concentrations. When necessary,

samples were diluted to fit the range of linearity standards. Table 3 lists the test substances,

spiking solutions, and standard dilutions used throughout this study.

Table 3: Test Substances and Standards

Compounds

Use Reference

No. Purity Source

Expiration

Date

Malathion Test Substance 1436 99.5% ChemService 5/31/16

Phosmet Test Substance 1437 99.5 ChemService 11/30/15

Zeta-cypermethrin Test Substance 1438 99.4 ChemService 3/31/18

Fenpropathrin Test Substance 1441 99.3 ChemService 6/30/18

Solutions & Dilutions of Test Substances

Compound Use Solution

No. Conc. Solvent

Expiration

Date

Malathion

Spiking 14361 1 mg/mL acetonitrile 5/22/14

Spiking 143611 100 ug/mL acetonitrile 5/22/14


Std verification 14362 1 mg/mL acetonitrile 6/10/14

Std verification 143621 100 ug/mL acetonitrile 6/10/14


Zeta-cypermethrin







Fenpropathrin







Phosmet






Mixed Solutions

Compounds Solution No. Conc. Solvent Expiration

Data

Malathion; Zeta-cypermethrin;

Fenpropathrin; Phosmet

M0313T-8 100 µg/mL each acetonitrile 5/22/14



M0313T-10 10 µg/mL each toluene 5/22/14



M0313T-22 1 µg/mL toluene 5/22/14



M0313T-23 0.5 µg/mL toluene 5/22/14



M0313T-24 0.2 µg/mL toluene 5/22/14



M0313T-25 0.1 µg/mL toluene 5/22/14



M0313T-26 0.05 µg/mL toluene 5/22/14

All standard solutions were stored in the freezer at



PSA and magnesium sulfate. This tube was then mixed and centrifuged again. Finally, 4 mL

of the resulting organic solvent was solvent exchanged to toluene and brought to final

volume for analysis.

B. Analytical Limits

The working method was validated by fortifying and recovering malathion, zeta-

cypermethrin, phosmet and fenpropathrin from control blueberries. The method was

validated in triplicate at three concentration levels: 0.05 ug/g, 0.5 ug/g and 5 ug/g (6 ug/g for

zeta-cypermethrin). Results from the method validation are presented in Section V. Results.

C. Instrumentation

Pesticide residue concentrations were determined using one of three instruments. Instrument

conditions are presented below.

A Varian 3400 CX gas chromatograph with pulsed flame photometric detection (GC/PFPD)

and 8200 CX autosampler was used for malathion and phosmet determination. Integration of

chromatographic data was performed using the Star Workstation software.

Column: Alltech EC-1, 15m x 0.53mm, 1.2 μm film thickness

Carrier gas: Ultrapure helium, flow ca. 12 mL/min.

Temperatures: Detector: 300°C

Injector port: 225 to 250°C at 250°C/min

Oven program

Initial: 100°C

ramp 30°C/min to 300°C, hold 1 min.

Injection volume: 2 μl

Detector: Air

Hydrogen

Nitrogen makeup gas

Retention time: Based on the observed retention times of external calibration

standards in each set.

An Agilent 6890N gas chromatograph with micro-electron capture detection (GC/µECD) and

7683 Autosampler was used for fenpropathrin detection and quantification. Integration of

chromatographic data was performed using Chemstation software.

Column: DB-5ms, 30m x 0.32mm, 0.25 μm film thickness

Carrier gas: Ultrapure helium, constant flow 2.2 mL/min.

Temperatures: Injector port: splitless, 250°C

Oven program

Initial: 100°C

ramp 25°C/min to 150°C,





Detector: µECD 250°C; hydrogen 2 mL/min; air 60 mL/min;

nitrogen makeup 30 mL/min



An Agilent 6890N gas chromatograph with mass spectrometry detection (GC/MS) and 7683

Autosampler was used for zeta-cypermethrin detection and quantification. Integration of

chromatographic data was performed using Chemstation software.

Column: DB-5ms, 25m x 0.25mm, 0.25 μm film thickness

Carrier gas: Ultrapure helium, constant flow 2.2 mL/min.

Temperatures: Injector port: 250°C

Oven program

Initial: 100°C

ramp 25°C/min to 150°C,



Detector: Source 230 ˚C, Quad 150 ˚C

SIM Zeta-cypermethrin: 91 m/z, 163 m/z, and 181 m/z



To verify the reliability of the GC instruments, calibration standards were inserted into the

sample set during each GC analysis. The peak area counts and retention times for the

compounds were assessed for reproducibility and accuracy. Additionally, extracts were

injected in duplicate. If extract peak areas agreed within 20% then the average of the two

results were used to calculate concentrations.

D. Quantification

The quantification of pesticide residues in 15 g blueberry was performed by electronic peak

area measurement of each pesticide and comparison to the linear regression from at least four

standards in the concentration range of sample extracts. To assure high quality during GC

operation, all samples were bracketed with external calibration standards during the

analytical set. For each analytical set, linearity and calibration standards were used to

construct the calibration curves using a spreadsheet program (Excel®).

The residue concentration in the blueberry samples is calculated by multiplying the

calculated concentration by the equivalent final volume of the sample extract, and then

dividing by the weight of berry sample. Results are reported as total concentration of each

individual pesticide in blueberry.



For example, set-24, sample 0313-SO-FS33, the malathion linear regression line of best fit,

computed from the combined linearity and calibration standards of this set (n=15, R2=0.999)

is expressed by equation 1:

Eq. 1 Y =m X + B

Where Y is peak area, m is the slope of the line, X is detected concentration, and B is the

intercept.

Y = 9017.934196 x X – 44.6356526

4 mL of the acetonitrile extract was exchanged to toluene for analysis and brought to a final

volume of 2 mL. This is equivalent to 4 g of crop in 2 mL. The average peak area count from

two injections of the sample was 8959.5. Because this is a fortified sample, the peak area of

the control is subtracted from the peak area of the fortified sample. However, there was no

malathion detected in the corresponding control sample in this set. The concentration (in

µg/mL) of malathion in the extract is calculated according to Eq. 1:

8959.5 = 9017.934196 x X – 44.6356526

X=0.998 µg/mL malathion

The concentration of malathion in the blueberry sample is then figured by multiplying by the

ratio of the final volume to the sample weight:

(0.998 µg/mL malathion)(2 mL/4 g) = 0.50 µg/g malathion

To assess overall analysis precision and percent recovery on a per-set basis, control samples

were fortified with a known amount of standard prior to extraction. For each analytical set,

percent recovery for the fortified sample was calculated according to Equation 2. When

necessary, control-sample peak area was subtracted from fortified recovery sample peak of

similar dilution for fortified-residue determination.

Eq. 2 % Recovery = (amount detected*) x 100

Amount fortified

* amount detected is calculated from fortified peak area minus control peak area.

For example, sample 0313-SO-FS33 was a fortified sample spiked with 7.5 µg malathion

(0.5 µg/g in blueberry). The percent recovery of malathion in the extract is then calculated by

eq. 2.

% Recovery = (0.50 µg/g) x 100 = 100%

µg/g

The same calculation method was used for each of the pesticides in this study.

E. Interferences

The GC/PFPD analysis for malathion and phosmet was very straight forward and sensitive.

The quantitation of phosmet often required additional sample dilutions and reanalysis to suit

the range of standards.



In the case of zeta-cypermethrin there was a large interfering peak at the retention time of the

compound which prevented use of µECD for quantitation. The use of GC/MS-single ion

monitoring overcame this problem but the interference still existed to some degree. The zeta-

cypermethrin peak is a cluster of four isomers of the compound. To adequately quantify the

compound the integration program was set to force the peak and sum all peak areas within

the retention time window.

Typical for ECD chromatography, the µECD chromatograms have some interfering peaks at

the lower concentration levels, making integration of the peak of interest difficult.

Additionally, matrix enhancement was present which required the use of matrix-matched

standards for all berry sample analyses.

F. Confirmatory Techniques

Matrix-matched analytical standards were used to confirm the presence of malathion, zeta-

cypermethrin, fenpropathrin, and phosmet by retention times.

G. Time Required for Analysis

The time required for an experienced person to work up a set of samples (generally five

samples, one control, and one fortified sample) was approximately 6 hours. The duration of

the GC analyses of each set depended on which compounds were of interest in the samples.

Sample sets were analyzed on multiple instruments after extraction. Each sample set was

injected using the auto sampler associated with the instrument.

H. Modifications or Potential Problems

High-quality reagents, pesticide grade or better, must be used throughout the study to avoid

chromatography problems and contamination in the control.

Method development work indicated a significant matrix enhancement effect characterized

by improved peak shape and peak response in the presence of matrix compared to the

analytical standards made in pure solvent. To overcome the influence of the matrix, matrix-

matched standards were created for each set.

The QuEChERS method was quick and easy and yielded reliable extraction results. The

method uses far less solvent than traditional liquid-liquid extraction, however the method

introduces a lot of salt and co-extractable components to the sample extracts. The

consumption of disposable supplies, need for matrix standards and the greatly increased

maintenance requirements on the GC inlet and column make this method less than ideal for a

project of this magnitude. It is highly recommended that a better extraction method be used

for future blueberry MRL studies.



V. Results

A. Method Validation and Recovery

All reagents and instruments used during the course of this study are commercially available

and typical of what would be present in most analytical laboratories. The working method

was validated at three concentration levels, 0.05 µg/g, 0.5 µg/g and 5 µg/g. The low end

fortification of 0.05 µg/g was designated as the method’s limit of quantitation (mLOQ) for

malathion, zeta-cypermethrin, fenpropathrin, and phosmet. The method limit of detection

(mLOD) was empirically estimated at approximately 0.01 µg/g for malathion, fenpropathrin

and phosmet. However, due to background in the control samples which was occasionally as

high as the equivalent of 0.02 µg/g zeta-cypermethrin the LOD for that compound was

empirically determined at half the mLOQ, or 0.025 µg/g zeta-cypermethrin. Table 4 lists the

method validation results. Table 5 provides the concurrent recovery results for malathion,

zeta-cypermethrin, fenpropathrin, and phosmet in the fortified samples extracted with each

set.

Table 4

Method Validation

Percent Recoveries

Sample ID

Fortificatio

n Level

(µg/g) Malathion Phosmet Fenpropathrin

Zeta-

cypermethrin

0313-Y2-MV11 0.05 113.1% 112.3% 102.1% rejected

0313-Y2-MV11re1 0.05 102.0% 100.6% 100.5% 86.6%

0313-Y2-MV12 0.05 112.5% 112.5% 106.0% 85.7%

0313-Y2-MV13 0.05 111.6% 115.6% 104.9% 79.7%

0313-Y2-MV14 0.5 93.4% 91.4% 90.1% 86.3%

0313-Y2-MV15 0.5 96.4% 92.4% 92.6% 89.1%

0313-Y2-MV16 0.5 97.1% 92.2% 93.2% 84.9%

0313-Y2-MV17 5 102.8% 103.0% 102.0%

0313-Y2-MV18 5 96.5% 96.5% 98.0%

0313-Y2-MV19 5 95.4% 91.9% 97.3%

0313-Y2-MV20 6 112.7%

0313-Y2-MV21 6 99.9%

0313-Y2-MV22 6 96.9% 1 re = this set was re-extracted a second time due to initially high (rejected) zeta-cypermethrin

recovery



Table 5

Concurrent Fortified Samples

Percent Recoveries

Sample ID

Fortification

Level

(µg/g) Set Malathion Phosmet Fenpropathrin

Zeta-

cypermethrin

0313-Y-FS10 0.05 SET1RE1 118.4% 118.6% NA 78.1%

0313-Y-FS11 0.05 SET2RE 101.1% 106.0% NA 37.1%2

0313-Y2-FS12 0.05 SET3RE 104.5% 113.3% NA 53.2%2

0313-Y-FS15 0.05 SET6RE 109.5% 105.5% NA 86.2%

0313-SO-FS16 0.05 set7 101.7% 110.1% NA 104.9%

0313-SO-FS21 0.05 set12 101.2% 87.4% NA 86.8%

0313-SO-FS22 0.05 set13 114.6% 106.7% NA 77.7%

0313-SO-FS24 0.05 set15 94.2% 96.2% NA 103.6%

0313-SO-FS26 0.05 set17 105.3% 112.1% NA 113.4%

0313-SO-FS27 0.05 set18 103.7% 109.4% NA 96.3%

0313-EFO-FS36 0.05 set27 103.4% 105.9% 110.9% 100.9%

0313-SO-FS28 0.1 set 19 108.2% 104.0% NA 79.0%

0313-SO-FS29 0.1 set20 102.7% 106.2% NA 102.0%

0313-SO-FS30 0.1 set21 100.5% 100.5% 94.8% 79.6%

0313-SO-FS32 0.1 set23 98.1% 104.2% NA 89.6%

0313-Y-FS13 0.5 SET4RE 99.8% 104.8% NA NA

0313-Y-FS14 0.5 SET5RE2 99.6% 103.0% NA NA

0313-SO-FS17 0.5 set8 96.2% 100.6% NA 89.0%

0313-SO-FS18 0.5 set9 78.4% 78.5% NA 75.8%

0313-SO-FS19 0.5 set10 90.3% 91.3% NA 76.6%

0313-SO-FS20R 0.5 set11re 93.5% 97.7% NA 84.1%

0313-SO-FS23 0.5 set14 113.3% 124.9% NA NA

0313-SO-FS25 0.5 set16 101.7% 130.3% NA 83.2%

0313-SO-FS31 0.5 set22 110.0% 122.8% NA 114.2%

0313-EFO-FS33 0.5 set24 99.8% 118.2% 98.0% 95.4%

0313-EFO-FS34 0.5 set25 114.4% 115.9% 93.8% 95.8%

0313-EFO-FS35 0.5 set26 92.6% 98.9% 97.5% 98.0%

0313-EFO-FS37 0.5 set28 100.9% 108.6% 96.9% 97.8%

0313-072713-C-FS1 0.5 Storstab 100.3%

89.8% 85.3%

Overall Average Recovery 102.0% 105.0% 98.1% 88.7%

Standard Deviation 8% 11% 6% 15%

Total Count (includes validation) 39 38 17 35 1 re = these sets were re-extracted due to one or more poor recoveries.

2 These recoveries accepted. Results were low due to high control peak which was subtracted

from the fortified sample peak for calculation.



B. Storage Stability

To verify stability of malathion, zeta-cypermethrin, fenpropathrin, and phosmet on

blueberries during frozen storage, FEQL fortified organic control berries purchased from a

grocery store at 0.5 µg/g on 9/4/2013. These storage stability samples, were maintained in

the freezer (ID Dasher) with study samples. Storage stability samples were extracted on

3/19/2014 according to the analytical method to verify the stability of the pesticides of

interest in frozen storage. This storage interval represents 196 days of demonstrated storage

stability. All berry samples from this study were extracted within 74 days of sampling. Table

6 provides the storage stability recovery results for malathion, zeta-cypermethrin,

fenpropathrin, and phosmet on blueberry.

Table 6

Storage Stability Samples

Percent Recoveries

Sample ID Fortification

Level

(µg/g) Malathion Phosmet

1 Fenpropathrin

Zeta-

cypermethrin

0313-Y2-SS1 0.5 89.5% 87.1% 87.0% 78.7%

0313-Y2-SS2 0.5 86.7% 80.1% 93.0% 88.7%

0313-Y2-SS3 0.5 87.4% 87.2% 97.1% 93.7% 1

Phosmet quantified against prepared standards because matrix control had detectable levels of phosmet.

C. Residue Results

This project monitored the pesticide residue on marketable fruit from two different

application methods one day before application through approximately 14 days after

application. Figures 2-4 illustrate the individual pesticide decline after application. Figure 5

is a plot of all monitored pesticides for the duration of the study that also included Imidan.

Table 7 provides the results for the analyzed MRL blueberry samples. All residues are

expressed as micrograms of pesticide per gram of blueberry (µg/g or ppm). Results below the

method limit of detection are listed as



per year where up to 2.5 pints can be applied for any one application. Although this is data

from a single field study, it is reasonable to state that 4 seasonal blueberry applications at

1.25 pints/acre will not trigger MRLs in the US (8 ppm), or Korea (10 ppm). However, other

Pacific Rim MRLs may be exceeded. Japan’s current MRL is 0.5 ppm where Taiwan’s is

more conservatively set at 0.1 ppm. When developing a harvest program for malathion, the

grower may choose to delay picking 3-5 days later than the allowed 1 day PHI to better

insure that field residues will not trigger a Japan MRL concern. However, this data is only

from one season and some level of risk of exceeding the MRL can still exist.

Mustang Maxx: Figure 3 shows field residues before and after Mustang Maxx

applications in early to late August 2013. The good reproducibility among the duplicate

composited berry sample data points for M and AB applications at each interval date and

consistent recovery among 35 fortified samples (89 +

15%) indicate that testing laboratories

should find similar concentrations in marketable berries. Mustang Max berry residues (as

zeta-cypermethrin) were found at much lower than US (MRL = 8 ppm) and Pacific Rim

MRLs from Korea and Japan (respectively 10 and 0.5 ppm). It is important to note that

Taiwan does not currently provide an MRL for the active ingredient zeta-cypermethrin in

Mustang Maxx. As such, any detected residue may trigger a trade barrier concern. The

appreciably slower rate of residue decline when compared to organophosphorus insecticides

is typical of pyrethroid insecticides and again similar to recent cherry decline work by

Haviland and Beers (2012). We did observe a consistently higher level of Mustang Maxx

residues after the second air blast application. Although results from any one-season decline

study make it difficult to precisely predict residues that may occur under differing climatic

and growing conditions, it is reasonable to state that growers should be wary of making too

many consecutive applications of this substance if planning on exporting to countries such as

Japan.

Danitol: Currently, this substance can only be applied twice in any one growing season

and was used in late August as a clean-up application. Because of its longer-lasting efficacy

on SWD (Lynell Tanigoshi, personal communication), we anticipated that this pyrethroid

chemistry would decline slowly in the field as is evident in Figure 4. Decline on/in blueberry

was similar to the recent decline study conducted at a similar rate on sweet cherries by

Haviland and Beers (2012). Although the Danitol data again represents a single PNW field

study, it is reasonable to anticipate that Danitol applied at the commercial rate of 16 fluid oz

per acre should not trigger MRLs in the US (8 ppm), Japan (5 ppm), or Taiwan (3 ppm).

However, Korea MRLs may likely be exceeded well after the 3 day PHI. Fenpropathrin, the

active ingredient in Danitol appears to be a longer lasting pyrethroid. The grower may

consider using this substance as a start and late season finish SWD treatment since current

label use of this material (as of 2013) only allows two seasonal applications,.

Cumulative Season-long Field Residues: Malathion, Mustang Maxx, and Danitol

blueberry residues were measured in the field on 32 separate sampling events from late July

through mid-September. Residues of Imidan (phosmet) were also assessed over the 48 day

spray period. Figure 5 provides the residue data for the four compounds. This profile

suggests that cumulative residues over the growing season may be effective in controlling

SWD field populations thus reducing the need for weekly applications. As a result, the

grower should consider season-long residual pesticide field concentrations together with

scouting as part of the SWD spray management program.



Figure 2: Malathion applications on 7/28/2013 and 8/11/2013

Figure 3: Mustang Maxx (zeta-cypermethrin) applications on 8/4/2013 and 8/18/2013

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

2

Mal

ath

ion

(p

pm

)

Malathion Applications

Field Control (ppm)

Mistigation-T(ppm)Mistigation-TD(ppm)Airblast-T (ppm)

Airblast-TD (ppm)

0.000

0.050

0.100

0.150

0.200

0.250

0.300

zeta

-Cyp

erm

eth

rin

(p

pm

)

Mustang Maxx Applications

Field Control(ppm)Mistigation-T(ppm)Mistigation-TD(ppm)



Figure 4: Danitol (fenpropathrin) application by airblast sprayer on 9/1/2013

Figure 5: Cumulative pesticide concentrations, monitored 7/27/2013-9/25/2013

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

Fen

pro

pat

hri

n (

pp

m)

Danitol Application

Field Control(ppm)Airblast-T (ppm)

Airblast-TD(ppm)

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

Pes

tici

de

(pp

m)

Date Malathion Mistigation (ppm) Phosmet mistigation (ppm)Zeta-cypermethrin mistigation (ppm) Malathion Airblast (ppm)Phosmet airblast (ppm) Zeta-cypermethring airblast (ppm)



Table 7

Analysis Results

Sample IDs Sampling

Date

Treatment Status


Date of extraction

Set Malathion

(µg/g) Phosmet

(µg/g) Fenpropathrin

(µg/g)

Zeta-cypermethrin

(µg/g)

0313-C-072713 7/27/2013 M(-1) 9/23/2013 set2re ND 0.32 NA



Sample IDs Sampling

Date

Treatment Status


Date of extraction

Set Malathion

(µg/g) Phosmet


(µg/g)

Zeta-cypermethrin

(µg/g)

0313-M-073113-TD 7/31/2013 M3 9/24/2013

0.10 0.18 NA NA

0313-AB-073113-T 7/31/2013 M3 9/24/2013

0.37 0.41 NA NA

0313-AB-073113-TD 7/31/2013 M3 9/24/2013

0.49 0.34 NA NA

0313-C-080213 8/2/2013 M5 9/24/2013 set5RE2 ND 0.64 NA NA

0313-M-080213-T 8/2/2013 M5 9/24/2013

0.06 0.18 NA NA

0313-M-080213-TD 8/2/2013 M5 9/24/2013

0.06 0.21 NA NA

0313-AB-080213-T 8/2/2013 M5 9/24/2013

0.28 0.48 NA NA

0313-AB-080213-TD 8/2/2013 M5 9/24/2013

0.18 0.46 NA NA

0313-C-080313 8/3/2013 MM(-1) 9/25/2013 set6RE ND 0.85 NA



Sample IDs Sampling

Date

Treatment Status


Date of extraction

Set Malathion

(µg/g) Phosmet


(µg/g)

Zeta-cypermethrin

(µg/g)

0313-M-080713-TD 8/7/2013 M10, MM3 10/1/2013



Sample IDs Sampling

Date

Treatment Status


Date of extraction

Set Malathion

(µg/g) Phosmet


(µg/g)

Zeta-cypermethrin

(µg/g)

0313-M-081313-TD 8/13/2013 M2 10/15/2013

0.15 0.19 NA



Sample IDs Sampling

Date

Treatment Status


Date of extraction

Set Malathion

(µg/g) Phosmet


(µg/g)

Zeta-cypermethrin

(µg/g)

0313-AB-081813-T 8/18/2013 M7, MM14, MM0

10/21/2013

0.15 0.19 NA

0.18

0313-AB-081813-TD 8/18/2013 M7, MM14, MM0

10/21/2013

0.13 0.20 NA

0.15

0313-C-081913 8/19/2013 MM1 10/22/2013 set20 ND 1.43 NA



Sample IDs Sampling

Date

Treatment Status


Date of extraction

Set Malathion

(µg/g) Phosmet


(µg/g)

Zeta-cypermethrin

(µg/g)

0313-C-082513 8/25/2013 M14, MM7, D0

10/30/2013 11/5/2013


ND 0.91 ND



Sample IDs Sampling

Date

Treatment Status


Date of extraction

Set Malathion

(µg/g) Phosmet


(µg/g)

Zeta-cypermethrin

(µg/g)

0313-AB-090213-TD 9/2/2013 D1 11/6/2013

0.12 0.09 0.52 0.07

0313-C-090313 9/3/2013 D2 11/6/2013 set26 1.34 0.63



Appendix A: Protocol



Appendix B: Working Method



Appendix C: Sample Chromatograms

Figure C1 - Malathion & Phosmet 0.5 ug/mL standard in blueberry extract matrix

malathion 0.5 ug/mL

phosmet 0.5 ug/mL



Figure C2 – Malathion & Phosmet: Control berry extract, 0313-EFO-C33 in 2 mL

malathion expected

retention time ~4.5 min;

phosmet expected retention

time ~6.0 min



Figure C3 – Malathion & Phosmet: fortified recovery sample, 0313-EFO-FS33 in 2 mL

malathion, 0.998 ug/mL in 2 mL

extract, equivalent to 0.5 ug/g;

phosmet, 1.18 ug/mL in 2 mL

extract, equivalent to 0.59 ug/g



Figure C4 – Malathion & Phosmet: mistigation sample, 0313-M-083013-T in 2 mL







Figure C5 – Malathion & Phosmet: airblast sample, 0313-AB-083013-T in 4 mL







Figure C6 – Malathion & Phosmet: field control sample, 0313-C-083013 in 2 mL

malathion, ND in 2 mL extract,

equivalent to 0.83 ug/g;

phosmet: Sample later diluted and

reanalyzed for phosmet, 0.67 ug/g



Figure C7 - Zeta-cypermethrin 0.5 ug/mL standard in blueberry extract matrix

Zeta-cypermethrin 0.5 ug/mL

SIM, cluster of peaks at 15.68 min



Figure C8 - Zeta-cypermethrin Control berry extract, 0313-EFO-C33R in 2 mL

Zeta-cypermethrin background,

0.02 ug/g in control



Figure C9 - Zeta-cypermethrin fortified recovery sample, 0313-EFO-FS33R in 2 mL

Zeta-cypermethrin 0.954 ug/mL in 2

mL extract, equivalent to 0.48 ug/g



Figure C10 - Zeta-cypermethrin mistigation sample, 0313-M-083013-TR in 2 mL

Zeta-cypermethrin 0.072 ug/mL in 2

mL extract, equivalent to



Figure C11 - Zeta-cypermethrin airblast sample, 0313-AB-083013-TR in 2 mL

Zeta-cypermethrin 0.224 ug/mL in 2 mL




Figure C12 - Zeta-cypermethrin field control sample, 0313-C-083013R in 2 mL

Zeta-cypermethrin 0.056 ug/mL in 2 mL

extract, equivalent to



Figure C13 – Fenpropathrin 0.5 ug/mL standard in blueberry extract matrix

Fenpropathrin 0.5 ug/mL



Figure C14 - Fenpropathrin Control berry extract, 0313-EFO-C37 in 2 mL

Fenpropathrin, expected retention

time 14.77 min



Figure C15 – Fenpropathrin fortified recovery sample, 0313-EFO-FS37 in 2 mL

Fenpropathrin 0.969 ug/mL in 2 mL




Figure C16 – Fenpropathrin airblast sample, 0313-AB-092513-T in 2 mL





Figure C17 – Fenpropathrin field control sample, 0313-C-092513 in 2 mL


extract, equivalent to

maximum residue levels with decline for three insecticides on … · 2014. 11. 19. · richland, wa...

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