Boscalid Summary of Analytical Chemistry and Residue Data Barcode D421150 

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

WASHINGTON, D.C. 20460 

OFFICE OF CHEMICAL SAFETY AND 

POLLUTION PREVENTION 

MEMORANDUM 

Date: 

Subject: 

From: 

Through: 

To: 

06/30/2014 

Boscalid. Petition for the Establishment of Permanent Tolerances and 

Registration for Use on Herb Subgroup 19A and Dill Seed. Request for Crop 

Group Expansions/Revisions for Stone Fruit Group 12-12 and Tree Nut Group 

14-12. Summary of Analytical Chemistry and Residue Data. 

PC Code: 128008 DP Barcode: D421 150 

Decision No.:484932 Registration Nos.: 7969-198, 7969-199 

Petition No.: 3E8215 Regulatory Action: Section 3 Registration 

Risk Assessment Type: NA Case No.: N/A 

TXR No.: NA CAS No.: 188425-85-6 

MRID Nos.: 4701480 1-47014803 40 CFR: 180.589 

Stephen Funk, Senior Chemist {1.' / 1/1! ~ Y 

Risk Assessment Branch III (RAB III) J F ~I () 

Health Effects Division (HED; 7509P 

Risk Assessment Branch III (RABIII)/J / j Christine Olinger, Branch Chief ~ 

Health Effects Division (HED; 7509'(Y ~ 

Barbara Madden, RM05 

Andrew Ertman 

Registration Division (RD; 7505P) 

And 

Barry O'Keefe, Senior Biologist 

Risk Assessment Branch III (RABBI) 

Health Effects Division (HED; 7509P) 

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Boscalid Summary of Analytical Chemistry and Residue Data Barcode 0421150 

OCSPP860 MRID Number Title 

Series 

Guideline 

860.1500 4701480 1 D. Carpenter, 2006, BAS 5 I 6: Magnitude of the Residue in Dill. 

Crop Field Unpublished Study Prepared by BASF Agro Research, University of 

Trials Florida and Artichoke Research Assn., Project No. 08691/03/BAR03. 

08691 , 2000/5001019.214p. 

860. 1500 47014802 D. Carpenter, 2006, BAS 5 16: Magnitude of the Residue on Chives. 

Crop Field Unpublished Study Prepared by BASF Agro Research, University of 

Trials Maryland and U.S. Dept of Agriculture Agr. Res. Service, Project Number 

08793, 08793/03/BAR05. I 73 p. 

860.1500 47014803 D. Carpenter, 2006. BAS 5a6: Magnitude of the Residue on Basil. 

Crop Field Unpublished Study Prepared by BASF Agro Research, Cornell University 

Trials and Artichoke Research Assn, Project Number 08792, 08792/03/BAR04. 

203 p, 

Page 2 of29 
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Table of Contents

1.0 Executive Summary............................................................................................................ 5

2.0 Regulatory Recommendations............................................................................................ 6

2.1 Data Deficiencies/Data Needs.......................................................................................... 6

2.2 Tolerance Considerations................................................................................................. 6

2.2.1 Enforcement Analytical Method............................................................................... 6

2.2.2 Recommended Tolerances........................................................................................ 7

2.2.3 Revisions to Petitioned-For Tolerances.................................................................... 7

2.2.4 International Harmonization ..................................................................................... 8

2.3 Label Recommendations.................................................................................................. 8

3.0 Introduction......................................................................................................................... 8

3.1 Chemical Identity ............................................................................................................. 8

3.2 Physical/Chemical Characteristics................................................................................... 9

3.3 Pesticide Use Pattern/Directions for Use (860.1200)....................................................... 9

4.0 Metabolite/Degradate Residue Profile.............................................................................. 10

4.1 Nature of the Residue..................................................................................................... 10

4.1.1 Summary of Plant Metabolism (860.1300)............................................................. 10

4.1.2 Summary of Livestock Metabolism (860.1300)..................................................... 10

4.1.3 Summary of Confined Rotational Crops (860.l850)............................................... 11

4.1.4 Summary of Metabolites and Degradates............................................................... 11

4.2 Comparison of Metabolic Pathways .............................................................................. 12

4.3 Residues of Concern Summary and Rationale............................................................... 12

5.0 Residue Profile.................................................................................................................. 13

5.1 Residue Analytical Methods (860.1340)........................................................................ 13

5.1.1 Data Collection Methods ........................................................................................ 13

5.1.2 Multi-Residue Methods (860.1360)........................................................................ 14

5.1.3 Tolerance Enforcement Methods............................................................................ 14

5.1.4 Submittal of Analytical Reference Standards (860.1650) ...................................... 14

5.2 Storage Stability (860.1380) .......................................................................................... 14

5.3 Residue Data .................................................................................................................. 15

5.3.1 Crop Field Trials (860.1500) .................................................................................. 15

5.3.2 Field Rotational Crops (860.1900) ......................................................................... 16

5.3.3 Processed Food and Feed (860.1520)..................................................................... 17
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5.3.4 Meat, Milk, Poultry and Eggs (860.1480) .............................................................. 17

5.3.5. Food Handling (860.1460)...................................................................................... 18

5.3.6 Water, Fish, and Irrigated Crops (860.1400).......................................................... 18

6.0 Tolerance Derivation ........................................................................................................ 18

Appendix A. Tabular Summary of Metabolites........................................................................... 19

Appendix B. Metabolic Pathways................................................................................................ 23

Appendix C. International Residue Limits Table ........................................................................ 26

Appendix D. OECD MRL Calculation Procedure Inputs/Outputs.............................................. 27

 
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1.0 Executive Summary

Boscalid, 2-chloro-N-(4 ́-chloro[1,1 ́-biphenyl]-2-yl)-3-pyridinecarboxamide, is a carboxamide 

(anilide) class fungicide that inhibits mitochondrial respiration, thereby inhibiting spore 

germination, germ tube elongation, mycelial growth, and sporulation in all major stages of fungal 

development and reproduction necessary for disease development in a variety of vegetable, fruit 

and row crops. There are currently two water-dispersible granular (WDG) boscalid end-use 

products (EPs) registered to BASF in the US for use on food/feed crops, one containing only 

boscalid and one which is a mixture of two active ingredients. The single active ingredient 

formulation is a 70% WDG (Endura® Fungicide; EPA Reg. No. 7969-197) and the mixture 

formulation is a WDG containing 25.2% boscalid and 12.8% pyraclostrobin (Pristine®

Fungicide; EPA Reg. No. 7969-199). The latter is the subject of the current registration action.

Only boscalid is addressed in this document; pyraclostrobin is being evaluated separately. 

The Interregional Research Project Number 4 (IR-4) is proposing new uses for boscalid 

(Pristine® Fungicide) on the herb subgroup 19A and dill. The relevant field trial data were 

reviewed previously, and that review is incorporated by reference: D373144, C. Olinger, 

11/27/2011. The proposed use for the herb subgroup 19A and for dill is up to two applications of 

a WG formulation with a seasonal maximum rate of 0.58 lb ai/acre and a 0 day pre-harvest 

interval (PHI). 

IR4 is also requesting crop group conversions for stone fruit 12-12 and nut tree group 14-12. 

The nature of boscalid residues in primary crops and livestock is adequately understood, based 

on the acceptable metabolism studies on lettuce, grapes, beans, goats, and hens. For purposes of 

tolerances and dietary risk assessment, the HED has concluded that the residue of concern in 

plant commodities is boscalid, and the residue of concern in livestock commodities include 

boscalid, its 5-hydroxy metabolite (M510F01), and the glucuronic acid conjugate of the 5-

hydroxy metabolite (M510F02).

An adequate gas chromatography/mass spectrometric detection (GC/MS) method (Method 

D0008) is available for enforcing boscalid tolerances in plant commodities, and an adequate 

GC/electron capture detection method (Method DFG S19) is available for enforcing the 

tolerances in livestock commodities. These methods have been found adequate by the Analytical 

Chemistry Branch (ACB) of the Biological and Economic Analysis Division (BEAD).

An adequate data collection method is available for plant commodities. Boscalid residues in 

plant commodities were determined using liquid chromatography with tandem mass 

spectrometric detection (LC/MS/MS) method (BASF Method D9908). This method was 

adequately validated in conjunction with the analysis of field trial study samples, and the 

validated limit of quantitation (LOQ) is 0.05 ppm for boscalid in all plant commodities tested.

Residues of boscalid and its metabolite M510F01 were not adequately recovered using the 

multiresidue methods.
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Adequate storage stability studies are available indicating that boscalid is relatively stable at 

≤-20oC in various plant commodities for up to 24 months. The available storage stability data 

are adequate and support the storage conditions and durations for chives, dill, and basil samples 

from the current field trials.

There are no feed commodities associated with chives, dill, and basil. Therefore, the livestock 

diets are not impacted, and the existing livestock commodity tolerances remain adequate.

The data generated from chives, dill, and basil field trials are adequate and support the proposed 

uses of the 25% WDG formulation of boscalid on these crops. An adequate number of tests were 

conducted on the crops in the appropriate geographic regions, and the tests were conducted at 

~1x the proposed use rate. Samples were collected around the proposed preharvest interval 

(PHI) and analyzed for residues of boscalid. Samples of basil from each trial were dried and 

analyzed to provide data for dried herbs. 

Adequate confined, limited and extensive field rotational crop studies are available supporting 

the existing tolerances for indirect residues of boscalid in rotational crops. These data support 

the 14-day plant-back interval currently specified for crops without boscalid uses. No additional 

rotational crop data are required for purposes of this petition. 

2.0 Regulatory Recommendations

HED has examined the residue chemistry database for boscalid. There are no residue chemistry 

considerations that would preclude granting the requested registration and establishing the 

recommended tolerances for boscalid on the herb subgroup 19A (fresh and dried) and on dill 

seed. The specific tolerance recommendations are discussed in 2.2, and label modifications are 

discussed in section 2.3.

The requested crop group conversions are acceptable.

2.1 Data Deficiencies/Data Needs

There are no deficiencies or data needs related to the requested new registrations, new tolerances, 

and crop group conversions.

2.2 Tolerance Considerations

2.2.1 Enforcement Analytical Method

PP#1F6313; DP# 278385, M. Nelson, 8/15/2003

DP# 284510; D. Swineford and E. Kolbe; 8/12/2003 (PMV memo)

An adequate gas chromatography/mass spectrometry (GC/MS) method (Method D0008) is 

available for enforcing boscalid tolerances in plant commodities. Residues are extracted using 

an aqueous organic solvent mixture followed by liquid/liquid partitioning and column clean-up. 
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Quantitation is by GC/MS, using selected ion monitoring (SIM) of major ions. The method lists 

monitoring ions of m/z 342, 142, or 140, and notes that any ion can be used for quantitation 

based on the cleanness of the chromatograms. Quantitation is performed using an external 

calibration curve of boscalid standards. Adequate validation data were submitted, including 

independent laboratory validation (ILV) data (MRID 45405101). The validated LOQ is reported 

to be 0.05 ppm for residues of boscalid in plant matrices. The ACB/BEAD concluded that the 

method is acceptable for enforcement purposes in plants.

2.2.2 Recommended Tolerances

It is recommended that tolerances be established for residues of the fungicide boscalid, including 

its metabolites and degradates, in or on dill seed and the herb subgroup 19A. Compliance with 

the tolerance levels is to be determined by measuring only boscalid, 3-pyridinecarboxamide, 2-

chloro-N-(4′-chloro[1,1'-biphenyl]-2-yl). The tolerance expression is aligned with the 

requirements of the S. Knizner memo dated 05/27/2009. 

Table 2.2.2. Tolerance Summary for Boscalid

Commodity Proposed 

Tolerance 

(ppm)

Existing 

Tolerance

HED-Recommended 

Tolerance (ppm)

Comments 

(correct commodity 

definition)

Herb subgroup 

19A

190 - 150

Dill, seed 300 - 100

Fruit, stone, 

group 12

- 3.5 Revoke Crop group conversion

Fruit, stone, 

group 12-12

3.5 - 3.5 Crop group conversion

Nut, tree, group 

14

- 0.70 Revoke Crop group conversion

Nut, tree, group 

14-12

0.70

-

0.70 Crop group conversion

Pistachio - 0.70 Revoke Crop group conversion. 

Member of group 14-12.

2.2.3 Revisions to Petitioned-For Tolerances

The stone fruit and tree nut group conversions occur without modification of the existing 

tolerances.

The recommended tolerance for the herb subgroup 19A is 150 ppm, based on the HAFT for basil 

and the processing factor for drying. Dried basil had residues in excess of those found on 

dillweed, fresh basil, and chives. The petitioned for tolerance of 190 ppm is not supported by the 

field trial data and the Organization for Economic Cooperation and Development (OECD)

tolerance calculation procedure. 

The recommended tolerance for dill seed is 100 ppm, based on evaluation of the 0 day PHI data 

with the OECD calculation procedure. It appears that proposed 300 ppm tolerance included data 

from an exaggerated application rate.
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A revised Section F is needed for the herb subgroup 19A and for dill seed.

2.2.4 International Harmonization

Canada and Codex have not established maximum residue limits (MRLs)/tolerances for herbs or 

dill seed, and therefore there is no harmonization issue.

For stone fruit, Canada has an MRL of 1.7 ppm and Codex has and MRL of 3 ppm. The US 

tolerance is 3.5 ppm, based on the evaluation of peach, plum, and cherry data (D364447, A. 

Acierto, 10/16/09). The individual commodity tolerance estimates were 1.6 ppm for plum, 3.0 

ppm for peach, and 3.5 ppm for cherry. The Canada MRL of 1.7 ppm was the former US 

tolerance prior to the latest data review. The tolerance cannot be lowered to 3 ppm to harmonize 

with Codex, as the cherry data necessitate a higher value. The tree nut tolerance (0.7 ppm) is 

harmonized with Canada. The Codex tree nut MRL (0.05 ppm) is lower than the US tolerance, 

and harmonization is not possible.

2.3 Label Recommendations

No changes to the Pristine label are necessary.

3.0 Introduction

Boscalid is a carboxamide (anilide) class fungicide that inhibits mitochondrial respiration, 

thereby inhibiting spore germination, germ tube elongation, mycelial growth, and sporulation in 

all major stages of fungal development and reproduction necessary for disease development in a 

variety of vegetable, fruit and row crops. It is formulated with pyraclostrobin.

3.1 Chemical Identity

Table 3.1. Nomenclature of Boscalid and its Hydroxy Metabolite.

Compound

Common name Boscalid; Nicobifen

Company experimental name BAS 510 F

IUPAC name 2-chloro-N-(4׳-chlorobiphenyl-2-yl)nicotinamide

CAS name 2-chloro-N-(4'-chloro[1,1'-biphenyl]-2-yl)-3-pyridinecarboxamide

Molecular weight 343.2

CAS registry number 188425-85-6

End-use product (EPs) 25.2% WDG (Pristine® Fungicide; EPA Reg. No. 7969-199, also contains 12.8% 

pyraclostrobin)

N

N

O

Cl

Cl
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Table 3.1. Nomenclature of Boscalid and its Hydroxy Metabolite.

Hydroxy-metabolite

Common name Boscalid hydroxy metabolite

Company experimental name M510F01 (glucuronide conjugate – M510F02)

CAS name 2-chloro-N-(4'-chloro-5-hydroxy-biphenyl-2-yl)nicotinamide

Molecular weight 359.2

3.2 Physical/Chemical Characteristics

Table 3.2. Physicochemical Properties of Boscalid.

Parameter Value References

Melting point/range 142.8-143.8 C MRIDs 45404802 and 

pH NA (does not dissociate in water) 45404804-45404809

Relative Density (20oC) 1.381g/cm3

Water solubility (20oC) 4.64 mg/L at pH 6

Solvent solubility (g/100 mL at 20oC) acetone 16-20 ethyl acetate 6.7-8.0 

methanol 4-5 2-propanol <0.01 

acetonitrile 4-5 dichloromethane 20-25 

toluene 2-5 n-heptane <0.01

1-octanol <0.01 olive oil 2.9

N,N-DMF >25

Vapor pressure 7 x 10-9 hPa 

Dissociation constant, pKa None (does not dissociate in water)

Octanol/water partition coefficient, 

Log(KOW)

2.96 

UV/visible absorption spectrum UV molecular extinction (e[lmol-1cm-1]): 3.15 

x104at 228 nm; 1.53 x103at 290 nm

3.3 Pesticide Use Pattern/Directions for Use (860.1200)

Table 3.3 Summary of Proposed Directions for New Use of Boscalid

Applic. Timing, 

Type, and 

Equip.

Formulation

[EPA Reg. 

No.]

Applic. 

Rate

(lb ai/A)

Max. 

No. 

Applic. 

per 

Season

Max. 

Seasonal 

Applic. Rate

(lb ai/A)

PHI

(days)

Use Directions and Limitations

Herb Subgroup 12A and Dill

Foliar, ground or 

aerial

25.2% 

Pristine® WG

7969-199

0.29 2 0.58 0

For aerial application, use no less than 5 

gallons of spray solution per acre. 

Repeat applications at a minimum of 7 

days. To limit development of 

resistance, do not make more than 2 

N

N

O

Cl

Cl

OH
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Table 3.3 Summary of Proposed Directions for New Use of Boscalid

Applic. Timing, 

Type, and 

Equip.

Formulation

[EPA Reg. 

No.]

Applic. 

Rate

(lb ai/A)

Max. 

No. 

Applic. 

per 

Season

Max. 

Seasonal 

Applic. Rate

(lb ai/A)

PHI

(days)

Use Directions and Limitations

applications per season. The restricted 

entry interval (REI) is 12 hours.

The proposed label for end use product 7969-199 (Pristine® fungicide) includes changes for crop 

group/subgroup conversions. The stone fruit group was expanded from the commodities of 

group 12 to the commodities of group 12-12. The tree nut group was expanded from the 

commodities of group 14 to the commodities of group 14-12. No changes were made in the 

good agricultural practices (GAPs) for stone fruits and tree nuts from the previous label of 

06/04/2012.

Conclusions: The submitted use directions are sufficient to allow for evaluation of the submitted 

residue data relative to the proposed use pattern for herb subgroup 19A and dill. The proposed 

label changes related to crop group/subgroup conversions are acceptable. There are no label 

deficiencies.

4.0 Metabolite/Degradate Residue Profile

4.1 Nature of the Residue

4.1.1 Summary of Plant Metabolism (860.1300)

PP#1F6313; DP# 278385; M. Nelson; 8/15/2003

HED MARC Decision Memo; DP# 286786; M. Nelson; 1/09/2003

The nature of boscalid residues in primary crops is adequately understood, based upon 

acceptable grape, lettuce and bean metabolism studies; these studies were reviewed in the initial 

boscalid petition, PP#1F6313. No significant metabolism of boscalid occurred in grapes or 

lettuce; unchanged parent was the only component identified, accounting for 92-98% and 99% 

total radioactive residues (TRR), respectively. In bean plants, boscalid metabolized slowly; 

unchanged parent was the major component identified, accounting for up to 72% TRR in dry 

bean seeds, and 99% TRR in bean plants. Cleavage products, 1-(chlorophenyl)-2-aminobenzene 

and 2-chloronicotinic acid, were present in small amounts, accounting for <1% and <10% TRR, 

respectively.

HED has concluded that the parent compound, boscalid, is the sole residue of concern in primary 

crops for purposes of risk assessment and the tolerance expression. The cleavage products were 

not included, based on the limited cleavage which occurred, and the low levels of their ingestion 

expected from dietary and environmental sources. 

4.1.2 Summary of Livestock Metabolism (860.1300)

PP#1F6313; DP# 278385; M. Nelson; 8/15/2003

HED MARC Decision Memo; DP# 286786; M. Nelson; 1/09/2003
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The nature of boscalid residues in livestock is adequately understood, based upon acceptable 14C 

metabolism studies conducted on lactating goats and laying hens. In both goats and hens, parent 

boscalid, M510F01 (hydroxy metabolite), and M510F 02 (M510F01 glucuronide) were 

identified as the major residues, each with ≥10% TRR. No amide bridge cleavage products were 

identified. Based on the structural similarity of boscalid and M510F 01, and the fact that the 

enzymatic hydrolysis step in the proposed enforcement method will release M510F 02 back to 

free M510F 01, HED concluded that the combined residues of parent boscalid, M510F 01 and 

M510F02 are the residues of concern in livestock matrices for purposes of risk assessment and 

the tolerance expression. 

4.1.3 Summary of Confined Rotational Crops (860.l850)

PP#1F6313; DP# 278385, M. Nelson, 8/15/03

HED MARC Decision Memo; DP# 286786; M. Nelson; 1/09/2003

The nature of the residue in rotational crops is adequately understood and was summarized in a 

previous residue chemistry summary document. A total of 52.6-96.1% of the TRR was 

identified in lettuce, radish roots and tops, and wheat forage and straw from the 30-, 120-, 270-, 

and 365-day PBIs. The parent, BAS 510 F, was the major residue identified in these 

commodities, accounting for 50.0-96.1% TRR (0.009-3.156 ppm). The glucoside metabolite 

M510F61 was identified in radish tops (all PBIs), radish roots (120- and 365-day PBIs only), 

wheat forage (all PBIs), and wheat straw (all PBIs); M510F61 accounted for 0.9-21.2% TRR 

(0.001-0.423 ppm). Unknown metabolites accounted for up to 22.7% TRR; however, individual 

peaks that were present at >10% TRR were each <0.04 ppm. Bound residues in certain samples 

of lettuce, radish tops and roots, and wheat forage and straw were tentatively demonstrated to be 

due to the incorporation of radioactivity into protein, lignin, and cellulose at levels totaling up to 

9.7% TRR. The remaining nonextractable residues were <0.05 ppm and were not further 

characterized.

A total of 1.9-35.4% of the TRR was identified in wheat grain from the 30-, 120-, 270-, and 365-

day PBIs. The parent, BAS 510 F, was the only compound identified in wheat grain at all PBIs, 

accounting for 9.6-35.4% TRR (0.008-0.028 ppm) in diphenyl-label grain and 1.9-6.1% TRR 

(0.005-0.015 ppm) in pyridine-label grain. Unknown metabolites accounted for 5.6% TRR 

(0.010 ppm). Bound radioactivity in wheat grain was tentatively demonstrated to be due to 

incorporation of radioactivity into starch, at 0.6-4.3% TRR (0.001-0.004 ppm) for the diphenyl 

label samples and 36.2-48.4% TRR (0.061-0.118 ppm) for the pyridine label samples, and 

protein, at 4.9-9.6% TRR (0.002-0.012 ppm) for the diphenyl label samples and 3.1-9.6% TRR 

(0.005-0.027 ppm) for the pyridine label samples. Nonextractable residues were 30.3-71.6% 

TRR (0.007-0.174 ppm) in diphenyl-label grain samples and 17.4-26.4% TRR (0.026-0.072 

ppm) in pyridine-label grain samples; these residues were not further characterized.

HED has concluded that the residue of concern in rotated crops for purposes of risk assessment 

and the tolerance expression is parent compound.

4.1.4 Summary of Metabolites and Degradates

Appendix A lists the major metabolites and their chemical structures. Appendix B provides 

metabolic pathway diagrams for beans, goats, and hens.
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4.2 Comparison of Metabolic Pathways

No significant metabolism of boscalid occurred in grapes or lettuce. Unchanged parent was the 

only component identified, and it accounted for 92-98% and 99% TRR in grapes and lettuce, 

respectively. In bean plants boscalid metabolized slowly. Unchanged parent was up to 72% 

TRR in bean dry seeds and 99% TRR in bean plants. Cleavage products 1-(chlorophenyl)-2-

aminobenzene and 2-chloronicotinic acid were present in small amounts in various bean 

matrices, accounting for <1% and <10% TRR, respectively. These metabolites were also found 

in the rat.

Metabolism in rotational crops was similar to primary crops. In the rotational crops lettuce, 

radish (roots, tops) and wheat (forage), boscalid was the major residue identified (50-96% TRR), 

with the glucoside metabolite, M510F61, accounting for 1-21% TRR. Only parent was found in 

wheat grain.

In the goat and hen metabolism studies, parent, M510F01 (hydroxy metabolite), and 

M51F510F02 (glucuronic acid metabolite of M510F01) were the major metabolites. 

Metabolites arising from the cleavage of the amide bond of boscalid were not identified in the 

livestock metabolism studies. In rats, cleavage of the amide bond appears to be very limited, 

based on <2% of the identified radioactivity in urine as the cleavage product 2-chloronicotinic 

acid.

4.3 Residues of Concern Summary and Rationale

MARC Decision Memo, D286786, TXR#0051452, M. Nelson, 01/09/03

Table 4.3. Summary of Metabolites and Degradates to be included in the Risk 

Assessment and Tolerance Expression

Matrix Residues included in Risk 

Assessment

Residues included in 

Tolerance Expression

Plants

Primary Crop Boscalid Boscalid

Rotational Crop Boscalid Boscalid

Livestock

Ruminant Boscalid, M510F01, 

M510F02

Boscalid, M510F01, 

M510F02

Poultry Boscalid, M510F01, 

M510F02

Boscalid, M510F01, 

M510F02

Drinking Water Boscalid Not Applicable
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5.0 Residue Profile

5.1 Residue Analytical Methods (860.1340)

5.1.1 Data Collection Methods

D373144, C. Olinger, 11/27/2007

4701401.der2 (dill)

4701402.der2 (chives)

47014803.der2 (basil)

An adequate liquid chromatography/mass spectrometry/mass spectrometry (LC/MS/MS) method 

(BASF Method D9908) is also available for collecting residue data on plant commodities. 

Boscalid residues in all of the plant commodities associated with the current field trials were 

determined using this LC/MS/MS method. Using this method, residues are extracted with 

methanol:water:2 N HCl (70:25:5; v:v:v) and centrifuged or filtered. Residues are then 

partitioned into cyclohexane, concentrated to dryness, and redissolved in buffered 

methanol:water (80:20, v:v). Residues are determined by LC/MS/MS using the m/z 343→307 

transition for detecting and quantifying boscalid. Residues are quantified using an external 

calibration curve of boscalid standards. The validated limit of quantitation is 0.05 ppm for 

boscalid in all commodities tested. In conjunction with the current field trials, the method was 

adequately validated using control samples of each plant matrix fortified with boscalid at levels 

ranging from 0.05 to 200 ppm.

Concurrent recoveries of boscalid averaged 83% with a standard deviation of 6% for fresh dill 

and 80% with a standard deviation of 8% for dill seed. Apparent residues of boscalid were less 

than the lower level of method validation (<LLMV; <0.05 ppm) ppm in/on all control samples.

Concurrent recoveries of boscalid averaged 82% with a standard deviation of 13% for fresh 

basil. Concurrent recoveries of boscalid averaged 89% with a standard deviation of 10% for 

dried basil. Apparent residues of boscalid were <LLMV (<0.05 ppm) in/on all control samples. 

Concurrent recoveries bracketed residues found in treated samples. 

Concurrent recoveries of boscalid from chives averaged 82% with a standard deviation of 12%. 

This high degree of variability, indicated by the high standard deviation comes from the disparity 

between recoveries at 0.05 and 5.0 ppm. The average recovery for chives fortified with boscalid 

at 0.05 ppm was 91% with a standard deviation of 10%, and the recovery for chives fortified at 

5.0 ppm was 72% with a standard deviation of 4%. Apparent residues of boscalid were <0.05 

ppm (<LLMV) in/on all control samples. Concurrent recoveries did not bracket residues found 

in/on treated samples. However, there are adequate method recovery data from other leafy herbs 

(i.e., basil and dill) that were analyzed by the same method.

Conclusions.

The data collection method has been adequately validated via the concurrent recovery 

determinations. The LLMV is 0.05 ppm for boscalid.
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5.1.2 Multiresidue Methods (860.1360)

The data requirements for testing with the multiresidue methods in the Pesticide Analytical 

Manual (PAM I) have been fulfilled and were discussed in the earlier petitions. Residues of 

boscalid and its metabolite M510F01 were not adequately recovered using multiresidue methods. 

Protocol A was not applicable. Protocol B was not applicable for boscalid and yielded 

inconsistent recoveries of M510F01. Residues of boscalid and M510F01 had good responses 

with GC/electron capture detection (ECD) on a DB-1 column under Protocol C but neither 

analyte was recovered at ≥30% using Protocol D, E, and F. 

Conclusions. 

The PAM multiresidue methods are not suitable for the determination of boscalid.

5.1.3 Tolerance Enforcement Methods

PP#1F6313; DP# 278385, M. Nelson, 8/15/2003

DP# 284510; D. Swineford and E. Kolbe; 8/12/2003 (PMV memo)

An adequate GC/MS method (Method D0008) is available for enforcing boscalid tolerances in

plant commodities. The ACB/BEAD concluded that the method is acceptable for enforcement 

purposes in plants without the need for an EPA validation (DP# 284510; D. Swineford and E. 

Kolbe, 8/12/2003, PMV memo).

5.1.4 Submittal of Analytical Reference Standards (860.1650)

Analytical reference standards for boscalid and its hydroxy metabolite are currently available in 

the EPA National Pesticide Standards Repository.

5.2 Storage Stability (860.1380)

DP# 322235, D. Dotson, 11/03/2005

MRID 47584402.der

The collected samples of fresh dill and dill seed were stored frozen for 171 and 147 days, 

respectively, prior to analysis. Chive samples were stored frozen for 115 days prior to analysis. 

Basil samples were stored frozen for 172 days prior to analysis. No storage stability data were 

included in the study submission. However, previously submitted and reviewed data indicate 

that boscalid is stable under frozen storage conditions for at least 24 months in diverse crop 

matrices (DP# D322235, D. Dotson, 11/3/05). Adequate storage stability studies are available 

indicating that boscalid is relatively stable at ≤-20oC in fortified samples of cabbage (high water 

content), canola seed (high oil content), peach (high water content), sugarbeet roots (high starch 

content), peas (high water content), wheat grain (high starch content), wheat forage (foliage), and 

wheat straw (dry feed) for up to 24 months. Boscalid is stable at -5°C for up to 109 days (3.6 

months) in orange fruit (high acid content), dried pulp, juice and oil.

Conclusions.

While no storage stability data were submitted with the present field trial studies, adequate 
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storage stability data exist to support the intervals of frozen storage of the samples.

5.3 Residue Data

5.3.1 Crop Field Trials (860.1500)

D373144, C. Olinger, 11/27/2007

4701401.der2 (dill)

4701402.der2 (chives)

47014803.der2 (basil)

Herb subgroup 19A

Basil

IR-4 has submitted field trial data for boscalid on basil. Four field trials were conducted in North 

American Free Trade Agreement (NAFTA) Growing Zones 1 (NY, 1 trial), 3 (FL, 1 trial), 10 

(CA, 1 trial), and 11 (WA, 1 trial) during the 2003 growing season. The test formulation used in 

all trials was BAS 510 UCF (Endura® Fungicide, EPA Reg. No. 7969-197), a water dispersible 

granule (WDG) formulation containing 70% boscalid as the active ingredient. BAS 510 UCF 

was applied to basil as two directed foliar sprays at 0.30-0.32 lb ai/A/application for a total rate 

of 0.60-0.63 lb ai/A (~1x the maximum proposed seasonal rate of 0.58 lb ai/A). Applications 

were made beginning when basil plants were at the vegetative/flowering stage and repeated on a 

6- to 8-day retreatment interval using ground equipment (28-54 gal/A of spray volume) and did 

not include the use of a spray adjuvant.

Single control and duplicate treated samples of fresh basil were harvested from each test site at 0 

and 3 days after treatment (DAT). Additional fresh basil samples were collected at 0 DAT and 

then dried according to simulated commercial practices in order to generate residue data for dried 

basil. 

Chives

IR-4 has submitted field trial data for boscalid on chives. Four field trials were conducted in 

NAFTA Growing Zones 2 (MD, 1 trial), 5 (OH, 1 trial), 10 (CA, 1 trial), and 11 (WA, 1 trial) 

during the 2003 growing season. The test formulation used in all trials was BAS 510 UCF 

(Endura® Fungicide, EPA Reg. No. 7969-197), a WDG formulation containing 70% boscalid as 

the active ingredient. BAS 510 UCF was applied to established chive plants as two directed 

foliar sprays at 0.30-0.31 lb ai/A/application for a total rate of 0.60-0.62 lb ai/A (~1x the 

maximum proposed seasonal rate of 0.58 lb ai/A). Applications were made beginning when 

chive plants were at the vegetative stage and repeated on a 6- to 8-day retreatment interval using 

ground equipment (24-50 gal/A of spray volume) and did not include the use of a spray adjuvant.

Single control and duplicate treated samples of fresh chives were harvested immediately from 

each trial site following the last treatment (0 DAT). 
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Dill

IR-4 has submitted field trial data for boscalid on dill. Four field trials were conducted in 

NAFTA Growing Zones 2 (MD, 1 trial), 3 (FL, 1 trial), 10 (CA, 1 trial), and 11 (WA, 1 trial) 

during the 2003 growing season. The test formulation used in all trials was BAS 510 UCF 

(Endura® Fungicide, EPA Reg. No. 7969-197), a WDG formulation containing 70% boscalid as 

the active ingredient. BAS 510 UCF was applied to dill plants as two directed foliar sprays at 

0.29-0.31 lb ai/A/application for a total rate of 0.59-0.62 lb ai/A (~1x the maximum proposed 

seasonal rate of 0.58 lb ai/A). Applications were made beginning when dill plants were at the 

vegetative growth stage through seed production; the retreatment intervals were 6 to 8 days. 

Foliar sprays were made using ground equipment (28-62 gal/A of spray volume) and did not 

include the use of a spray adjuvant.

Single control and duplicate treated samples of fresh dill and dill seeds were harvested 

immediately from each trial site following the last treatment (0 DAT). 

A summary of residue data from the field trials is presented in Table 5.3.1. 

Table 5.3.1. Summary of Residue Data from Field Trials with Boscalid

Crop Matrix

Total Applic. 

Rate

(lb ai/A)

PHI 

(days)

Residue Levels of Boscalid (ppm)1

n Min. Max. HAFT Median

(STMdR)

Mean

(STMR) Std. Dev.

BASIL Proposed use pattern: Two foliar sprays at 0.29 lb ai/A/application for a seasonal rate of 0.58 lb ai/A with a 0-day PHI. 

Fresh Basil 0.60-0.63

0 8 11.3 30.6 24.1 15.5 17.7 7.2

3-4 8 2.0 16.0 13.5 9.3 8.7 4.9

Dried Basil 0 4 60.6 142.0 142.0 117.7 109.5 36

CHIVES. Proposed use pattern: Two foliar sprays at 0.29lb ai/A/application for a seasonal rate of 0.58 lb ai/A with a 0-day PHI.

Chives 0.60-0.62 0 8 1.6 13.2 12.8 11.6 9.5 4.8

DILL. Proposed use pattern: Two foliar sprays at 0.29 lb ai/A/application for a seasonal rate of 0.58 lb ai/A with a 0-day PHI.

Fresh Dill 

(dillweed) 0.60-0.61 0 8 5.88 29.2 28.6 15.6 16.3 8.5

Dill Seed 0.59-0.62 0 6 5.70 42.2 41.2 10.6 22.5 16

Dill Seed 0.91 0 2 117 129 123 N/A N/A N/A

1 n = number of samples, typically 2X number of trials. Min = lowest replicate sample value. Max = highest replicate sample 

value. HAFT = highest average field trial. STMdR = median of average field trials. Mean = mean of average field trials.

Conclusions. 

Studies reflect the proposed use pattern. The number of trials and geographic distribution are 

acceptable. The analytical method used is adequate for determination of the residue of concern, 

and the samples were stored frozen for intervals supported by the storage stability results.

5.3.2 Field Rotational Crops (860.1900)

PP#1F6313; DP# 278385, M. Nelson, 8/15/2003

DP# 322235, D. Dotson, 11/03/2005

DP# 323288, D. Soderberg, 6/14/2007 

Adequate limited and extensive field rotational crop studies are available supporting the existing 

tolerances for indirect residues in rotational crops. These data support the label-specific plant-
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back interval of 14 days for crops without boscalid uses. No additional rotational crop data are 

required for purposes of this petition. 

Conclusion: 

There are currently no deficiencies pertaining to rotational crops.

5.3.3 Processed Food and Feed (860.1520)

D373144, C. Olinger, 11/27/2007

47014803.der2 (basil)

Basil from each of the four field trials was dried.

Table 5.3.3.1 Residue Data from the Basil Processing Study with Boscalid

RAC

(trial #) Processed Commodity

Total Rate

lb ai/A PHI (day)

Residues (ppm) Processing Factor

Boscalid Boscalid

Fresh

Basil

(NY17)

RAC 

(prior to processing) 0.63 0

12.6 -

Dried Basil 60.6 4.8

Fresh Basil

(FL55)

RAC 

(prior to processing) 0.61 0

21.9 -

Dried Basil 142 6.5

Fresh Basil

(CA125)

RAC 

(prior to processing) 0.60 0

24.1 -

Dried Basil 129 5.4

Fresh Basil

(WA18)

RAC 

(prior to processing) 0.61 0

12.3 -

Dried Basil 106 8.6

The median processing factor for the conversion of fresh basil to dry basil is 6.0x.

Conclusion:

The four processing studies conducted for the production of dried basil are adequate to estimate a 

processing factor for the boscalid residue. In each of the trials, the fresh basil contained 

quantifiable residues of boscalid.

5.3.4 Meat, Milk, Poultry and Eggs (860.1480)

PP#1F6313; DP# 278385, M. Nelson, 8/15/2003

DP# 322235; D. Dotson, 11/03/2005

45405110.der (cattle feeding study)

45643801.der (poultry feeding study)

47584403.der (cattle feeding study)

DP# 364447; A. Acierto, 10/16/2009

47584403.der (cattle feeding study)

There are no proposed uses that are relevant to this guideline topic. There are no feed items 

associated with dill seed and the herb subgroup. Therefore, the previous livestock dietary intake 

calculations and resulting tolerance recommendations are not changed.
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5.3.5. Food Handling (860.1460)

This guideline requirement is not relevant to the current petition as there are no food-handling 

uses being proposed for boscalid.

5.3.6 Water, Fish, and Irrigated Crops (860.1400)

This guideline requirement is not relevant to the current petition as there are no aquatic uses 

being proposed for pyraclostrobin.

6.0 Tolerance Derivation

The Organization for Economic Cooperation and Development (OECD) calculation procedure 

was used to determine tolerance estimates for the relevant commodities. All field trial results 

were above the LOQ (0.05 ppm). See Appendix D. 

The tolerance estimates for the herbs fresh basil, fresh dill weed, and fresh chives are 60 ppm, 60

ppm, and 30 ppm, respectively. The tolerance estimate for dried basil is 150 ppm (24.1 ppm 

HAFT X 6.0 processing factor = 145 ppm, rounded to 150 ppm). The recommended tolerance 

for the herb subgroup 19A, which encompasses both fresh and dried herbs, is 150 ppm.

The tolerance estimate for dill seed, a spice, is 100 ppm.
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Appendix A. Tabular Summary of Metabolites 
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Appendix B. Metabolic Pathways

Metabolic pathway in beans
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Metabolic pathway in the goat
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Metabolic pathway in the hen
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Appendix C. International Residue Limits Table

Boscalid (128008; 06/30/2014)

Summary of US and International Tolerances and Maximum Residue Limits 

Residue Definition:

US Canada Mexico2 Codex3

40 CFR §180.589. Plant commodities:

boscalid, 3-pyridinecarboxamide, 2-chloro- N

-(4′-chloro[1,1'-biphenyl]-2-yl),

Plant commodities:

2-chloro-N-(4'-

chloro[1,1'-biphenyl]-2-

yl)-3-pyridinecarboxamide

- Plant commodities: 

boscalid. 

Commodity1 Tolerance (ppm) /Maximum Residue Limit (ppm)

US Canada Mexico2 Codex3

Herbs subgroup 19A

(fresh and dried)

150 None None

Dill, seed 100 None None

Nut, tree, group 14-12 0.70 0.7 0.05 (*)

Fruit, stone, group 12-12 3.5 1.7 3

1

Includes only commodities of interest for this action. Tolerance values should be the HED recommendations and 

not those proposed by the applicant.

2 Mexico adopts US tolerances and/or Codex MRLs for its export purposes.

3 * = absent at the limit of quantitation; Po = postharvest treatment, such as treatment of stored grains. PoP = 

processed postharvest treated commodity, such as processing of treated stored wheat. (fat) = to be measured on the 

fat portion of the sample. MRLs indicated as proposed have not been finalized by the CCPR and the CAC.
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Appendix D. OECD MRL Calculation Procedure Inputs/Outputs

Compound Boscalid Boscalid Boscalid Boscalid

Crop

Dill Seed Dillweed

Basil 

(fresh) Chives

Region / Country US US US US

GAP 2X0.3, 0 

day 2X0.3, 0 d 2X0.3, 0 d 2X0.3, 0 d

Total number of data 

(n) 3 4 4 4

Percentage of 

censored data 0% 0% 0% 0%

Number of noncensored data 3 4 4 4

Lowest residue 5.830 8.110 12.300 1.850

Highest residue 41.200 28.600 24.100 12.700

Median residue 20.600 14.300 17.250 11.750

Mean 22.543 16.328 17.725 9.513

Standard deviation 

(SD) 17.765 8.854 6.158 5.164

Correction factor 

for censoring (CF) 1.000 1.000 1.000 1.000

Proposed MRL 

estimate

- Highest residue 41.200 28.600 24.100 12.700

- Mean + 4 SD 93.603 51.744 42.357 30.170

- CF x 3 Mean 67.630 48.983 53.175 28.538

Unrounded MRL 93.603 51.744 53.175 30.170

Rounded MRL 100 60 60 30

High 

uncertaint

y of MRL 

estimate 

due to 

small 

dataset.

High 

uncertaint

y of MRL 

estimate 

due to 

small 

dataset.

High 

uncertaint

y of MRL 

estimate 

due to 

small 

dataset.

High 

uncertaint

y of MRL 

estimate 

due to 

small 

dataset.

Residues 

(mg/kg)

Residues 

(mg/kg)

Residues 

(mg/kg)

Residues 

(mg/kg)

20.600 28.600 12.600 11.000

41.200 12.200 21.900 12.500

5.830 16.400 24.100 12.700

8.110 12.300 1.850
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References:

DP Number: 410742

Subject: PP#2E8068. Boscalid; Petition for the Establishment of Permanent Tolerances 

and Registration for Use on Belgium Endive, Persimmon, and Globe Artichoke. 

Request for Crop Group Expansions/Revisions for Bulb Vegetable Group 3-07, 

Fruiting Vegetable 8-10, Citrus Fruit Group 10-10, Pome Fruit Group 11-10, 

Berry Subgroups 13-07A, B, F, and G, and Oilseed Group 20. Summary of 

Analytical Chemistry and Residue Data 

From: S. Funk

To: B. Madden/A. Ertman

Dated: 06/20/2013

MRIDs: 48897401, 48897402, 48897403

DP Numbers: 278385, 282532, 286787, 287829

Subject: PP#1F06313. BAS 510 F (Common Name: Boscalid), New Fungicide Active 

Ingredient. Residue Chemistry Summary Document.

From: M. Nelson

To: M. Rodriquez/C. Giles-Parker

Dated: 08/15/2003

MRIDs: 45405021-45405028, 45405101-45405128, 45405202-45405204, 45623401-

45623413, and 45643801

DP Number: 322235

Subject: PP#s 1F6313, 3E6791, 4F6875, and 5E6933: Boscalid, Registrant’s Response to 

Deficiencies Cited in Tolerance Petition 1F6313. Summary of Analytical 

Chemistry and Residue Data for Rotational Root Crops, Direct Uses on Celery, 

Spinach, Bananas, Strawberries, Almonds, and Potatoes, and Seed Treatment 

Uses on Bulb Vegetables, Brassica Leafy Vegetables, Legume Vegetables, 

Peanuts, and Sunflowers.

From: D. Dotson

To: J. Bazuin/T. Kish

Dated: 11/3/2005

MRIDs: 46145101, 46145102, 46160103, 46210606, and 46351401-46351405
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DP Number: 323288

Subject: Boscalid. Petition for a Tolerance for Belgian Endive; Petition for Increased 

Tolerances on Strawberry and the Berries Crop Group; Submission of Requested 

Field Trial Data on Cucumber, Mustard Greens and Sunflower; and Supplemental 

Field Trial Data on Fruiting Vegetables, Radishes, Spearmint, Peppermint, 

Grapes, and Stone Fruits; and Submission of Field Trials and a Processing Study 

for Cotton. Summary of Analytical Chemistry and Residue Data.

From: D. Soderberg

To: C. Swartz

Dated: 6/04/2007

MRIDs: 46512002, 46512003, 46637701, 46665501, 46665502, 46665503, 46665504, 

46665505, 46665506, 46713801, 46685902, 46685901