UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

WASHINGTON, D.C. 20460 

MEMORANDUM 

Date: 22-July-2015 

OFFICE OF 

CHEMICAL SAFETY AND 

POLLUTION PREVENTION 

SUBJECT: Fludioxonil; Petitions for Tolerances for Residues in/on Carrot, Stone Fruit, 

Group 12-12, and Rapeseed, Subgroup 20A. Summary of Analytical Chemistry 

and Residue Data. 

PC Code: 

Decision Nos.: 

Petition Nos.: 

071503 

491305, 491195 

4E8272 (Carrot) & 

4F8277 (Rapeseed) 

DP Barcodes: 

Registration Nos. 

Regulatory Action: 

Risk Assessment Type: NA Case No.: 

TXR No.: NA CAS No.: 

MRID No.: 49347001 /:1 /) tH.. ~~ 

From: 'William D. Wassell, Chemist fj;p 'rt-XI 

Risk Assessment Branch 1 (RAB 1) 

Health Effects Division (HED, 7509P) 

0421064, 0421602 

100-1242, 100-758 

Section 3 Registration 

7017 

131341-86-1 

§180.516 

Through: George F. Kramer, Ph.D., Branch Senior Chem~ tt ;::ISE 2 's-z 

RAB 1/HED (7509P) ;::::::::;--

To: Barbara Madden/ A. Willis Ertman, RM 05 

Registration Division (7505P} 

Executive Summary 

Fludioxonil, 4-(2,2-difluoro-1,3-benzodioxol-4-yl)-lH-pyrrole-3-carbonitrile, is a phenyl-pyrrole 

fungicide registered for use on a variety of field and vegetable crops, fruit trees, berries, herbs, 

and grasses. It can be applied as a seed treatment, an at-planting soil application, broadcast foliar 

applications, and/or post-harvest uses. A total of 26 end-use products (EPs) containing 

fludioxonil are currently registered to Syngenta Crop Protection for use on food/feed crops, with 

the majority of these EPs being registered for seed treatment uses. These EPs contain 0.13 to 

50% fludioxonil as the active ingredient (ai) and are formulated as wettable-powders (WP), 

water-dispersible granules (WDG), flowable-concentrates (FlC), flowable suspension 

concentrates (SC), and dusts. / 

Permanent tolerances have been established for residues of fludioxonil per se in/on a variety of 

plant commodities, ranging from 0.01 ppm on numerous commodities to 500 ppm on citrus oil 

[40 CFR §180.516(a)(l)]. Specifically, tolerances for residues of fludioxonil are established 

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Fludioxonil Summary of Analytical Chemistry and Residue Data DP#: 421064 

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in/on rapeseed, crambe, and lesquerella at 0.01 ppm, and stone fruit group 12 at 5.0 ppm. 

Additionally, permanent tolerances have been established for residues of fludioxonil and its 

metabolites converted to 2,2-difluoro-l,3-benzodioxole-4-carboxylic acid in/on a livestock 

commodities ranging from 0.01 ppm to 0.05 ppm [40 CFR §180.516(a)(2)]. 

The Interregional Research Project No. 4 (IR-4) has proposed the use of Scholar® SC Fungicide 

(EPA Reg. No. 100-1242) on carrots as a post-harvest treatment for the control of white mold. 

Scholar® is an SC formulation which contains 1.92 lbs of fludioxonil per gallon. The proposed 

use on carrots is for a single dip or drench application at 16 fl. oz. product per 100 gallons (0.23 

lbs ai/100 gallon). Additionally, IR-4 has proposed the fludioxonil tolerance and use for stone 

fruit, group 12 be extended to the redefined stone fruit, group 12-12. The treatment of stone fruit 

is for the control of brown rot, gray mold, rhizopus rot, and gilbertella rot. In conjunction with 

the proposed use, IR-4 has proposed the following tolerances for fludioxonil residues in/on: 

 

Carrot ...................................................................................7.0 ppm 

Fruit, stone, group 12-12 ......................................................5.0 ppm 

In conjunction with this proposal, the tolerance for residues in/on vegetable, root, except sugar 

beet, subgroup 1B should be changed to root, except sugar beet and carrot, subgroup 1B. 

Additionally, tolerances for residues of fludioxonil in/on crambe, lesquerella, and flax seed 

should be deleted as the tolerance for residues on rapeseed subgroup 20A covers these 

commodities. 

Syngenta has proposed the use of fludioxonil on rapeseed subgroup 20A, except flax seed. 

Fludioxonil is registered for use as a seed treatment on rapeseed which is the representative 

commodity for subgroup 20A. The formulation registered for use on rapeseed is Maxim® 4FS 

(EPA Reg. No. 100-758) which contains 4 lbs ai per gallon. Maxim® 4FS is also registered for 

use on flax, crambe, and lesquerella which are also members of subgroup 20A. The tolerance 

level for residues of fludioxonil in/on rapeseed, crambe, and lesquerella is 0.01 ppm while the 

tolerance level for residues in/on flax is 0.05 ppm. The registered use on rapeseed, crambe, 

lesquerella, and flax is for the application of 0.08 to 0.16 fl oz of Maxim® 4FS per 100 lbs of 

seed (0.0025 to 0.0050 lbs ai/100 lbs seed) for protection against seed-borne and soil-borne fungi 

which cause decay, damping off, and seedling blight. In conjunction with the proposed use, 

Syngenta has proposed the following tolerance for fludioxonil residues in/on: 

 

Rapeseed, subgroup 20A, except Flax Seed .......................0.01 ppm 

Syngenta makes note that this requests reflects the established Canadian maximum residue limit 

(MRL) for residues at 0.01 ppm in/on rapeseed, but not the Codex MRL of 0.02 ppm. 

The nature of the fludioxonil residues in plants is adequately understood based on adequate 

metabolism studies on peaches, grapes, onions, and head lettuce and seed treatment applications 

to rice, wheat, cotton and soybeans. Based on the results from these studies, HED has 

determined that the residue of concern in plants following foliar applications is fludioxonil per 

se.

The nature of the residues in livestock is also understood based on the adequate goat and hen 

metabolism studies. For purposes of tolerance enforcement and risk assessment, the residues of 

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Fludioxonil Summary of Analytical Chemistry and Residue Data DP#: 421064 

Page 3 of 14 

concern in ruminants are fludioxonil and Metabolite B-1, and the residues of concern in poultry 

are fludioxonil, CGA-344623, and Metabolite I-1. 

Adequate high-performance liquid chromatography/ultraviolet light detector (HPLC/UV) 

methods (Syngenta Methods AG-597 and AG-597B) are available for enforcing tolerances of 

fludioxonil in plant commodities. In the current post-harvest trials, residues of fludioxonil in/on 

carrots were determined using a liquid chromatography and tandem mass-spectrometry detection 

(LC-MS/MS) method, which is a modified version of Method AG-597B. The LC-MS/MS 

method was adequately validated in conjunction with the analysis of samples from the postharvest trial. The validated limit of quantitation (LOQ) for fludioxonil was 0.01 ppm in each 

canola matrix, and the limit of detection (LOD) was 0.003 ppm. 

Based on the potential dietary exposure of livestock to fludioxonil residues from the current and 

proposed uses in the U.S., quantifiable residues of fludioxonil are not likely to occur in livestock 

commodities [40 CFR §180.6(a)(3)]. Therefore, HED has concluded that cattle and poultry 

feeding studies and tolerances for livestock commodities are not required at this time. 

The submitted carrot post-harvest data are adequate and support the proposed use on carrots. An 

adequate number of field trials were conducted at ~1x the maximum proposed application rate. 

Samples were collected after the treatment solution dried and analyzed using an adequate LCMS/MS method. The residue data would support a 7.0 ppm tolerance for residues of fludioxonil 

in/on carrots. 

Adequate confined and limited field rotational crop trials are available and support the labelspecified 30-day plant-back interval (PBI) for crops without uses on the fludioxonil label. The 

available data indicate that tolerances are not currently required for rotational crops. 

Regulatory Recommendations and Residue Chemistry Deficiencies

There are no residue chemistry issues that would preclude establishing a permanent tolerance for 

fludioxonil residues in/on carrots, stone fruit, group 12-12, and rapeseed, subgroup 20A, except 

flax seed. A human-health risk assessment for these uses is required. 

Background

Fludioxonil is a contact, phenyl-pyrrole fungicide which inhibits protein kinase (Group 12), 

leading to reduced fungal growth and development. In the U.S., fludioxonil is registered to 

Syngenta for use on a wide variety of field and vegetable crops, fruit trees, berries, herbs, and 

grasses. Fludioxonil is applied to food/feed crops as a seed treatment, at-planting soil 

application, broadcast foliar applications and/or post-harvest applications. 

In support for a purposed use on carrots as a post-harvest treatment, IR-4 has submitted data 

generated by The Pest Management Centre (PMC) of Agriculture and Agri-Food Canada 

(AAFC) for fludioxonil to support the proposed use on carrots. No new data have been 

submitted to support the expansion of the stone fruit and rapeseed uses. The chemical structure, 

nomenclature, and physicochemical properties of fludioxonil are presented in Tables 1 and 2. 

Page 3 of 22
Fludioxonil Summary of Analytical Chemistry and Residue Data DP#: 421064 

Page 4 of 14 

Table 1. Fludioxonil Nomenclature.

Compound 

Common name Fludioxonil 

Company experimental name CGA-173506 

IUPAC name 4-(2,2-difluoro-1,3-benzodioxol-4-yl) )-1H-pyrrole-3-carbonitrile 

CAS name 4-(2,2-difluoro-1,3-benzodioxol-4-yl)-1H-pyrrole-3-carbonitrile 

CAS registry number 131341-86-1 

End-use products (EPs) Scholar® SC Fungicide (EPA Reg. No. 100-1242) 

Maxim® 4FS Fungicide (EPA Reg. No. 100-758)

Table 2. Physicochemical Properties of Fludioxonil.

Parameter Value Reference 

Melting point 199.8°C DP# 325160, G. Kramer, 

pH 8-9 @ 25°C (1% aqueous dispersion) 11/16/2006 

Density 1.54 g/cm3 typical at 23°C 

Water solubility (25°C) 1.8 mg/L 

Solvent solubility (mg/L @ 25°C) Ethanol 44,000 

Acetone 190,000 

Toluene 2,700 

n-Octanol 20,000 

n-Hexane 7.8 

Vapor pressure (25°C) 2.9 x 10-9 mm Hg 

Dissociation constant, pKa pKa1 <0 

pKa2 ~ 14.1 

Octanol/water partition coefficient, Log(KOW) 4.12 @ 25°C 

UV/visible absorption spectrum 12,384 L/mol x cm @266 nm (neutral solution) 

12,327 L/mol x cm @ 265 nm (acidic solution) 

11,790 L/mol x cm @ 271 nm (basic solution) 

860.1200 Directions for Use

IR-4 is proposing the use of Scholar® SC Fungicide (EPA Reg. No. 100-1242) for the control of 

white mold on carrots. Applications are proposed as post-harvest in-line dip or drench 

applications at 16 fl oz (0.23 lbs ai) per 100 gallons. The application solution may be made 

using water, wax/emulsion, or aqueous dilution of wax/oil emulsion. The fruit should be dipped 

for approximately 30 seconds and allowed to drain. The following restriction is included: do not 

make more than one post-harvest application to carrots. 

The currently registered use for Scholar® SC on stone fruits (except cherries) is for in-line dip or 

drench application at 16 fl oz (0.23 lbs ai) per 100 gallons or in-line aqueous or fruit coating 

spray at 16 to 32 fl oz (0.23 to 0.46 lbs ai) per 200,000 lbs of fruit for the control of brown rot, 

gray mold, rhizopus rot, and gilbertella rot. The application may be made using water, 

wax/emulsion, or aqueous dilution of wax/oil emulsion. When performing the dip application, 

fruit should be dipped for approximately 30 seconds and allowed to drain. Use T-Jet, CDA, or 

similar application system for in-line aqueous or fruit coating applications. The following 

restrictions are included: do not make more than one post-harvest application to the fruit; for 

maximum efficacy, use low volume concentrate application systems for treatment of plums. The 

currently registered use for use for Scholar® SC on cherries is for in-line aqueous or flooder 

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Fludioxonil Summary of Analytical Chemistry and Residue Data DP#: 421064 

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application at 16 to 32 fl oz (0.23 to 0.46 lbs ai) per 50,000 lbs of fruit. The application solution 

may be made using water, wax/emulsion, or aqueous dilution of wax/oil emulsion. Use flooders, 

T-Jet, or similar application system. The following restrictions are included: do not make more 

than one post-harvest application to the fruit. 

The currently registered use for Maxim® 4FS (EPA Reg. No. 100-758) on rapeseed, flax, 

crambe, and lesquerella is for protection against seed-borne and soil-borne fungi which cause 

decay, damping-off, and seedling blight. Applications are made at 0.08 to 0.16 fl oz (0.0025 to 

0.0050 lbs ai) of formulated product per 100 pounds of seed. 

The proposed and registered use patterns are summarized in Table 3. 

Table 3. Summary of Directions for Use of Fludioxonil. 

Applic. Timing, 

Type, and Equip.1 

Formulation 

[EPA Reg. 

No.] 

Applic. Rate 

Max. 

No. 

Applic. 

per 

Season 

Max. 

Seasonal 

Applic. Rate 

PHI 

(days)

Use Directions and 

Limitations 

Carrots 

Post-harvest dip or 

drench 

Suspension 

concentrate

[100-1242] 

16 fl oz per 100 gallons 

(0.23 lbs ai) 1 

16 fl oz per 

100 gallons 

(0.23 lbs ai) 

NA 

The fruit should be dipped for 

30 seconds and allowed to 

drain. Do not make more than 

one post-harvest application. 

Stone Fruit except Cherry 

Post-harvest dip, 

drench, in-line 

aqueous or fruit 

coating spray 

Suspension 

concentrate

[100-1242] 

16 to 32 fl oz per 100 

gallons (dip, drench) or 

per 200,000 lbs fruit 

(aqueous or fruit coating 

spray) 

(0.23 to 0.46 lbs ai) 

1 32 fl oz 

(0.46 lbs ai) NA 

When performing the dip 

application, fruit should be 

dipped for approximately 30 

seconds and allowed to drain. 

Use T-Jet, CDA, or similar 

application system for in-line 

aqueous or fruit coating 

applications. Do not make 

more than one post-harvest 

application to the fruit; for 

maximum efficacy, use low 

volume concentrate 

application systems for 

treatment of plums. 

Cherry 

Post-harvest inline aqueous or 

flooder application 

Suspension 

concentrate

[100-1242] 

16 to 32 fl oz per 50,000 

lbs fruit 

(0.23 to 0.46 lbs ai) 

1 32 fl oz 

(0.46 lbs ai) NA 

Use flooders, T-Jet or similar 

application system. Do not 

make more than one postharvest application to the fruit. 

Rapeseed Subgroup 20A 

Seed treatment 

Water-based 

slurry 

[100-758] 

0.08 to 0.16 fl oz per 100 

lbs seed 

(0.0025 to 0.0050 lbs ai) 

1 

0.16 fl oz 

(0.0050 lbs 

ai) 

NA 

Seeds that are treated and 

bagged for later use must be 

labelled to say this seed has 

been treated with fludioxonil 

seed treatment. Do not use 

treated seed for feed, food, or 

oil purposes. 

Conclusions: The proposed use directions for carrots, stone fruit, and rapeseed subgroup 20A 

are adequate to allow for evaluation of the uses. The available field trial data for fludioxonil on 

carrots support the proposed use directions. 

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Fludioxonil Summary of Analytical Chemistry and Residue Data DP#: 421064 

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860.1300 Nature of the Residue - Plants

Memo, 10/27/97, S. Willett, D206301 

Memo, 08/31/98, W. Wassell, D246235 

Memo, 12/14/99, W. Donovan, D261603 

Memo, 02/12/2003, T. Bloem, D287808 

MARC Decision Memo, 1/18/2000, W. Donovan, D262022 

The nature of fludioxonil in plants is understood based on adequate metabolism studies utilizing 

foliar applications to peaches, grapes, onions, and head lettuce and seed treatment applications to 

rice, wheat, cotton, and soybeans. Based on the results of these studies, HED has determined 

that the residues of concern in plants is fludioxonil per se. 

860.1300 Nature of the Residue - Livestock

Memo, 12/18/95, S. Willett, D210762 

MARC Decision Memo, 01/18/2000, W. Donovan, D262022 

Adequate poultry and ruminant metabolism studies are available. The metabolism of fludioxonil 

in ruminants involves hydroxylation of the pyrrole ring followed by formation of glucuronide or 

sulfate conjugates. In poultry, fludioxonil is metabolized by oxidation, ring hydroxylation, 

degradation of the pyrrole moiety, and formation of glucuronide or sulfate conjugates. Based on 

the results of these studies, HED has concluded that the residues of concern in ruminants, for 

purposes of tolerance expression and risk assessment, are fludioxonil and Metabolite B-1 [4-

(2',2'-difluoro-1',3'-benzdioxol-4'-yl)-1H-pyrrole-3-carbonitrile, 2-O-glucuronide]. The residues 

of concern in poultry, for purposes of tolerance expression and risk assessment, are fludioxonil, 

CGA-344623 [2-cyano-3-(2,2-difluoro-1,3-benzdioxol-4-yl)succinamic acid], and Metabolite I-1 

[4-(2',2'-difluoro-1',3'-benzdioxol-4'-yl)-pyrrole-3-carbonitrile, 1-O-sulfate ester]. 

860.1340 Residue Analytical Methods

Enforcement methods: Adequate HPLC/UV methods (Methods AG-597 and AG-597B) are 

available for enforcing tolerances for fludioxonil on plant commodities. The LOQs for these 

methods range from 0.008 to 0.05 ppm depending on the plant commodity. 

Data collection methods: In the submitted carrot field trials, residues of fludioxonil were 

determined using Method AG-597B which determines residues by analysis using LC-MS/MS. 

Residues were extracted by blending the sample in the presence of acetonitrile (ACN):water 

(90:10, v/v) twice. The extracts were centrifuged, combined, and adjusted to a total volume of 

200 mL. The ACN extract was concentrated on a rotary evaporator and a saturated solution of 

NaCl was added to the extract. The extract is then partitioned with dichloromethane and then 

evaporated to dryness. The extract is reconstituted in ACN containing 0.1 % acetic acid. 

Residues were analyzed by LC-MS/MS using the m/z 247→180 and m/z 247→125 ion 

transitions for quantification and confirmation of fludioxonil, respectively. Residues were 

quantified using external standards. The validated LOQ is 0.01 ppm and the LOD was reported 

as 0.003 ppm. 

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Fludioxonil Summary of Analytical Chemistry and Residue Data DP#: 421064 

Page 7 of 14 

The above method was adequately validated using control samples of carrot fortified with 

fludioxonil at levels of 0.01 to 4.0 ppm. 

Conclusions: Adequate methods are available for enforcing the proposed tolerance for residues 

on carrots and the residue data from carrot post-harvest trials were determined using an adequate 

LC-MS/MS method. 

860.1360 Multiresidue Methods 

DP# 206301, S. Willett, 3/01/1995 

Multiresidue method testing data are available for fludioxonil. Fludioxonil was tested according 

to Protocols C, D, and E using sorghum, corn, and potatoes. Recoveries were inadequate using 

corn and sorghum; however, fludioxonil was recovered from potatoes, a representative nonfatty 

crop. Testing was not conducted according to protocols A and B as fludioxonil does not have an 

N-methylcarbamate structure (protocol A) nor is it an acid or phenol (protocol B). Recoveries 

from potatoes (using multiresidue protocol D) were 49 to 121% at the 0.05 ppm fortification 

level, and 78 to 87% at the 0.5 ppm fortification level. Additionally, fludioxonil is recoverable 

by the multiresidue method QuEChERS using HPLC-MS/MS for analysis. 

860.1380 Storage Stability

DP# 216233, S. Willett, 8/17/1995 

DP# 258870, W. Donovan, 12/20/1999 

DP# 258861, W. Donovan, 11/29/1999 

DP# 280799, W. Donovan, 2/28/2002 

DP# 287808, T. Bloem, 2/12/2003 

Adequate storage stability data are available indicating that fludioxonil is completely stable at 

-20°C for at least 24 months in corn grain and forage, sweet corn ears, sorghum hay, and 

potatoes; 28.5 months in grapes; 12 months in carrots, broccoli, cabbage, and mustard greens; 6 

months in corn meal, sorghum flour, and potato flakes; and 4 months in stone fruits and 

raspberries. To date, no decline of fludioxonil during frozen storage has been observed in any 

plant commodities tested. 

The storage durations and conditions of samples from the canola field trials and processing 

studies submitted to support this petition are presented in Table 4. 

Table 4. Summary of Storage Conditions and Durations of Samples from Canola Field Trial and 

Processing Studies. 

Matrix Storage 

Temperature (°C) 

Actual Storage Duration 

(days) 

Interval of Demonstrated 

Storage Stability (days) 

Carrots ≤-15.6 162 365

Conclusions: Adequate storage stability data are available for fludioxonil in/on carrots to 

validate the storage interval for samples in the crop field trials. 

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Fludioxonil Summary of Analytical Chemistry and Residue Data DP#: 421064 

Page 8 of 14 

860.1480 Meat, Milk, Poultry, and Eggs 

DP# 287808, T. Bloem, 2/12/2003 

There are no livestock feeding studies available for fludioxonil. Based on the available goat and 

poultry metabolism data and the previously calculated dietary exposures of livestock to 

fludioxonil residues, HED previously concluded that quantifiable residues of fludioxonil were 

unlikely to occur in livestock commodities [40 CFR §180.6(a)(3)]. Therefore, cattle and poultry 

feeding studies and tolerances for livestock commodities were not required. 

The maximum dietary burdens of livestock to fludioxonil residues were previously calculated to 

be 0.13 ppm for beef cattle, 0.11 ppm for dairy cattle, 0.03 ppm for poultry, and 0.02 ppm for 

swine (DP# 287808, T. Bloem, 2/12/2003). The maximum dietary burdens of livestock to 

fludioxonil residues has been recalculated to be 0.047 ppm for beef cattle, 0.033 ppm for dairy, 

0.026 ppm for poultry, and 0.023 ppm for swine (Table 5). 

As the recalculated dietary burden does not alter HED’s previous conclusions regarding the need 

for livestock feeding studies and tolerances for livestock commodities. 

Table 5. Calculation of Dietary Burdens of Fludioxonil Residues for Livestock.

Feedstuff Dietary 

Component 

% Dry 

Matter 1 % Diet1 Residues (ppm)2 

Dietary Contribution 

(ppm)3

Beef Cattle

Alfalfa, hay R 89 15 0.01 0.002 

Corn, grain CC 88 25 0.02 0.006 

Sorghum, grain CC 86 25 0.02 0.006 

Potato, culls CC 20 30 0.024 0.030 

Flax, meal PC 88 5 0.05 0.0028 

TOTAL BURDEN 100 0.047 

Dairy Cattle 5

Alfalfa, forage R 35 20 0.01 0.006 

Grass, hay R 88 25 0.01 0.003 

Sorghum, grain CC 86 35 0.02 0.008 

Potato, culls CC 20 10 0.024 0.010 

Flax, meal PC 88 10 0.05 0.0057 

TOTAL BURDEN 100 0.033 

Poultry 

Sorghum, grain CC NA 75 0.02 0.015 

Canola, meal PC NA 5 0.016 0.001 

Flax, meal PC NA 20 0.05 0.01 

TOTAL BURDEN 100 0.026 

Swine 

Sorghum, grain CC NA 80 0.02 0.016 

Corn, grain CC NA 5 0.02 0.001 

Canola, meal PC NA 5 0.016 0.001 

Flax, meal PC NA 10 0.05 0.005 

TOTAL BURDEN 100 0.023 

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Fludioxonil Summary of Analytical Chemistry and Residue Data DP#: 421064 

Page 9 of 14 

1

 Potential dietary burdens for livestock were determined using recent Agency guidance on calculating 

reasonably balanced diets for livestock (memo, 6/30/2008). 2

 The tolerance level for the RAC was used for any associated processed fractions unless otherwise indicated. 3 Contribution = ([tolerance /% DM] X % diet) for beef and dairy cattle; contribution = ([tolerance] X % diet) for 

poultry and swine. 4

 Based on 0.02-ppm tolerance on root and tuber vegetables (group 1). 

5

 Although there is a 30 ppm tolerance for leaves of root and tuber vegetables, turnips tops were not included in 

the diet for dairy cattle as the label prohibits the feeding of leaves of root and tuber vegetables to livestock. 6

 Based on 0.01 ppm tolerance for rapeseed seed. 

860.1500 Crop Field Trials

Carrot: 

49347001.der.docx (Carrots - Canadian post-harvest trials) 

IR-4 has submitted residue data for fludioxonil on carrots to support the proposed use expansion 

to this crop. Two post-harvest trials were conducted in Canada, with one trial in Zone 1A (Nova 

Scotia) and one trial in Zone 12 (British Columbia). The carrots were grown during the 2009 

growing season. Samples of carrot roots were harvested from both trials, and stored for ~1-2 

months. The carrots were then treated with a mixture containing 0.3 g ai/L (0.0025 lbs ai/gal) 

fludioxonil SC formulation. At each trial site, two treatment regimens were used. For the first 

treatment, the test mixture was applied via a drench application (TRT 03), where the carrots were 

placed in a plastic mesh bag in a single layer and sprayed with test mixture for 10 seconds, then 

flipped over and sprayed for another 10 seconds; the spray rate was not indicated. For the 

second treatment, the test mixture was applied via a dip application (TRT 02), where the carrots 

were placed in plastic mesh boxes and submerged in the test mixture for ~30 seconds. An 

adjuvant was not added to the spray mixture for any of the applications. Samples of carrots were 

collected after the test mixture had dried on the day of application [0 DAA (days after 

application)] and placed in frozen storage. 

When carrots were treated with 1 application of fludioxonil at 0.3 g ai/L (0.0025 lbs ai/gal), 

fludioxonil residues ranged from 1.91 to 3.49 ppm for the dip application (TRT 02) and 1.63 to 

2.35 ppm for the drench application (TRT 03). The results of the post-harvest trials are 

summarized in Table 6. 

TABLE 6. Summary of Residue Data from Crop Field Trials with Fludioxonil.

Commodity Total Applic. 

Rate 

g ai/L 

(lbs ai/gal) 

DAA 

(days) 

Residue Levels 

 (ppm) 

n Min. Max. HAFT1 LAFT2 Median 

(STMdR) 

Mean 

(STMR) 

Std. Dev.

TRT 02 (Dip) 

Carrot roots 0.3 

(0.0025) 

0 8 1.91 3.49 -- -- 2.43 2.51 0.53 

2 -- -- 2.59 2.43 2.51 2.51 -- 

TRT 03 (Drench) 

Carrot roots 0.3 

(0.0025) 

0 8 1.63 2.35 -- -- 1.94 1.95 0.22 

2 -- -- 2.01 1.88 1.95 1.95 -- 1 HAFT = Highest Average Field Trial. 

2 LAFT = Lowest Average Field Trial. 

Page 9 of 22
Fludioxonil Summary of Analytical Chemistry and Residue Data DP#: 421064 

Page 10 of 14 

Stone Fruit, Crop Group 12-12: 

Memo, 11/16/2006, G. Kramer, D325160 

Tolerances are currently established for residues of fludioxonil in/on stone fruit, crop group 12 at 

5.0 ppm in conjunction with a post-harvest use of Scholar® SC. IR-4 has proposed to extend the 

tolerance and registered use for fludioxonil in/on crop group 12 to the newly defined crop group 

12-12 which includes additional commodities. 

Conclusions: HED has no objection to extending the tolerance and registered use for fludioxonil 

in/on crop group 12 to crop group 12-12. 

Rapeseed, Subgroup 20A: 

Memo, 08/31/1998, W. Wassell, D246235 

Tolerances are currently established for residues of fludioxonil in/on rapeseed and forage, 

crambe, and lesquerella at 0.01 ppm in conjunction with a seed treatment use of Maxim® 4FS. 

Additionally, a tolerance is currently established for residues of fludioxonil in/on flax at 0.05 

ppm in conjunction with a seed treatment use of Maxim® 4FS. Syngenta has proposed to extend 

the tolerance and registered use for fludioxonil in/on rapeseed to the rapeseed subgroup 20A. 

Rapeseed, canola varieties only, is the representative commodity for the rapeseed crop subgroup 

20A. Crambe, lesquerella, and flax are members of the rapeseed subgroup. 

Conclusions: HED has no objection to extending the tolerance and registered use for fludioxonil 

in/on rapeseed to the rapeseed subgroup 20A, except flax seed. 

860.1520 Processed Food and Feed

Memo, 11/04/2009, W. Wassell, D362488 

47644301.de4.doc (canola) 

Syngenta has previously submitted processing data for fludioxonil in/on rapeseed. Following a 

single broadcast foliar application of fludioxonil to canola at rates of ~750 g ai/ha (0.669 lbs 

ai/A), residues were <LOD (<0.003 ppm) in samples of canola seed, meal, and refined oil from 

both field trials. Therefore, processing factors could not be calculated. The theoretical 

processing factors for canola are 1.9x for meal and 3.0x for refined oil. 

Conclusions: The data indicate that quantifiable residues of fludioxonil are unlikely to occur in 

canola meal and refined oil following an application at 1x the maximum use rate; therefore, 

separate tolerances are not required for canola meal and refined oil. 

860.1650 Submittal of Analytical Reference Standards 

Analytical reference standards for fludioxonil and its metabolite B-1 are currently available at 

the EPA National Pesticide Standards Repository (personal communication with Theresa Cole, 

ACB, 11/03/2014). Availability of analytical grade standards are not an issue for these petitions. 

 

Page 10 of 22
Fludioxonil Summary of Analytical Chemistry and Residue Data DP#: 421064 

Page 11 of 14 

860.1850/1900 Confined and Field Accumulation in Rotational Crops

DP# 258865, W. Donovan, 12/17/1999 

MARC Decision Memo, DP# 262022, W. Donovan, 1/18/2000 

An adequate confined rotational crop study is available reflecting the application of [phenyl14C]fludioxonil to soil at ~1.0 lb ai/A. Based on the results from this study, HED has concluded 

that the residue of concern in rotational crops is fludioxonil per se. 

An adequate limited field rotational crop study is also available. At two test sites in CA and NY, 

fludioxonil (50% WP) was applied to bare soil as four broadcast applications at 0.25 lb 

ai/A/application at 7-day RTIs, for a total rate of 1.0 lb ai/A (1.1x maximum seasonal rate). 

Rotational crops of lettuce, turnips, and wheat were planted at each site at PBIs of 27 to 30 days. 

Single control and duplicate treated samples of lettuce, turnip roots and tops, and wheat forage, 

hay, grain, and straw were harvested from each trial at the appropriate stage for maturity, and 

samples were analyzed for residues of fludioxonil using an adequate HPLC/UV method (Method 

AG-597B). Residues of fludioxonil were <LOQ (<0.01 ppm) in/on all samples of each 

rotational crop matrix. 

These data support the 30-day PBI on the current fludioxonil labels and indicate that rotational 

crop tolerances are not currently required. 

860.1550 Proposed Tolerances

The Agency has determined that the residues of concern in plant commodities are fludioxonil. 

Permanent tolerances have been established for residues of fludioxonil. Permanent tolerances 

have been established [40 CFR §180.516(a)(1)] for residues of the fungicide fludioxonil, 

including its metabolites and degradates, in or on the various commodities ranging from 0.01 

ppm to 500 ppm. Compliance with the tolerance levels specified in the following table is to be 

determined by measuring only fludioxonil. 

Recommended Tolerances: Table 7 is a summary of the proposed and HED-recommended 

tolerances for residues of fludioxonil. A revised Section F specifying the new tolerance expression 

and the HED-recommended tolerances should be submitted. 

Table 7. Tolerance Summary for Fludioxonil.

Commodity Proposed 

Tolerance (ppm) 

Recommended 

Tolerance (ppm) 

Correct Commodity 

Definition/Comments 

To be established under 40 CFR §180.516 (a) General. (1) 

Carrots 7.0 

Fruit, stone, group 12-12 5.0 

Rapeseed subgroup 20A, except Flax Seed 0.01 

The U.S. tolerance and Codex and Canadian MRLs for fludioxonil in/on fruit, stone are 

harmonized. The U.S. tolerance and Canadian MRL for residues in/on carrots are harmonized; 

however the Codex MRL is significantly lower. The U.S. tolerance and Canadian MRL for 

residues in carrots are based on a post-harvest use whereas the Codex MRL is based on a foliar 

use. The U.S. tolerance and Canadian MRL for fludioxonil in/on rapeseeds are harmonized; 

however, the Codex MRL is not harmonized. Canadian MRLs for fludioxonil in/on flax seed, 

Page 11 of 22
Fludioxonil Summary of Analytical Chemistry and Residue Data DP#: 421064 

Page 12 of 14 

mustard seed, and poppy seed are not harmonized as these commodities are included in subgroup 

20A. 

Attachments: 

Appendix I. International Residue Limit Status Sheet. 

Appendix II. Tolerance-Assessment Calculations. 

Petition Numbers: 4E8272, 4F8277 

DP#s: 421064, D421602 

PC Code: 071503 

Page 12 of 22
Fludioxonil Summary of Analytical Chemistry and Residue Data DP#: 421064 

Page 13 of 14 

Appendix I. International Tolerances 

International Residue Limits 

Fludioxonil (071503; 10/30/2014) 

Summary of US and International Tolerances and Maximum Residue Limits 

Residue Definition: 

US Canada Mexico2 Codex3

40 CFR 180.490: 

Plant: 4-(2,2-difluoro-1,3-

benzodioxol-4-yl)-1-H-pyrrole3-carbonitrile Livestock: N/A 

4-(2,2-difluoro-1,3-

benzodioxol-4-yl) 

1H-pyrrole-3-

carbonitrile 

 Plants: Fludioxonil 

Livestock: fludioxonil 

and its benzopyrrole 

metabolites, determined 

as 2,2-difluoro-1,3-

benzodioxole-4-

caboxylic acid and 

expressed as 

fludioxonil. 

The residue is fat 

soluble. 

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

US Canada Mexico2 Codex 

Carrots 7.0 7 carrot roots 0.7 

Fruit, stone, group 12-

12 

5.0 

5.0 apricots, fresh 

prune plums, 

nectarines, peaches, 

plumcots, plums, 

prune plums, sweet 

cherries, tart 

cherries 

 5 Po 

Rapeseed, subgroup 

20A 

0.01 

0.05 flaxseeds 

0.02 mustard 

seeds, poppy seeds 

0.01 rapeseeds 

(canola) 

 0.02 rape seed (*) 

 

 

 

Completed: M. Negussie; 11/03/14 

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. 

 

Page 13 of 22
Fludioxonil Summary of Analytical Chemistry and Residue Data DP#: 421064 

Page 14 of 14 

Appendix II. Tolerance-Assessment Calculations. 

Fludioxonil 

Carrot 

Post-harvest 

16 fl oz per 100 gallons

(0.23 lbs ai) 

 

Total number of data (n) 4 

 

Percentage of censored data 0% 

Number of non-censored data 4 

 

Lowest residue (LR) 1.880 

Highest residue (HR) 2.590 

Median residue (STMR) 2.220 

 

Mean 2.228 

Standard deviation (SD) 0.337 

 

Correction factor for censoring (CF) 1.000 

 

Proposed MRL estimate 

 

Unrounded 6.683 

Rounded to the next MRL class 7 

 

High uncertainty of MRL estimate due to small dataset. 

Fludioxonil 

Carrot 

Post-harvest 

"16 fl oz per 100 gallons(0.23 lbs ai)" 

Residues (mg/kg) 

2.590 

1.880 

2.430 

2.010 

Page 14 of 22
Fludioxonil/FLD/ Syngenta Canada Inc. /SYZ 

DACO 7.4.117.4.2/0PPTS 860.1500/0ECD IIA 6.3.l , 6.3.2, 6.3.3 and IIIA 8.3.1, 8.3.2, 8.3.3 

- Crop Field Trial/ Residue Decline - Carrot roots 

Primary Evaluato 

Approved by 

W lliam D. Wassell, Chemist 

Risk Assessment Branch 1 (RABI); 

Heath Effects Division (HED) (7509P) 

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

RABI, HED (7509P) 

Date: 22-July-20I5 

Note: This DER was originally prepared by the Canadian Pest Management Regulatory Agency (PMRA). The 

DER has been reviewed by HED and revised to reflect current Office of Pesticide Programs (OPP) policies. 

STUDY REPORTS: 

PMRA No. 2309994. MRID No. 49347001. Subedi, K. (20I2) "Fludioxonil: Magnitude of the 

Residue on Carrots." Study Number AAFC08-013R. Laboratory Identification Number 

AAFC08-013R-556. Unpublished study prepared by Agriculture and Agri-Food Canada, Pest 

Management Centre. 302 pages. 

EXECUTIVE SUMMARY: 

The Pest Management Centre (PMC) of Agriculture and Agri-Food Canada (AAFC) has 

submitted residue data for fludioxonil on carrots to support the proposed use expansion to this 

crop. 

Two post-harvest trials were conducted in Canada, with one trial in Zone IA (Nova Scotia) and 

one trial in Zone I2 (British Columbia). The carrots were grown during the 2009 growing 

season. Samples of carrot roots were harvested from both trials, and stored for -I-2 months. 

The carrots were then treated with a mixture containing 0.3 g ai/L (0.0025 lbs ai/gal) fludioxonil 

soluble-concentrate (SC) formulation. At each trial site, two treatment regimens were used. For 

the first treatment, the test mixture was applied via a drench application (TRT 03), where the 

carrots were placed in a plastic mesh bag in a single layer and sprayed with test mixture for IO 

seconds, then flipped over and sprayed for another 10 seconds; the spray rate was not indicated. 

For the second treatment, the test mixture was applied via a dip application (TRT 02), where the 

carrots were placed in plastic mesh boxes and submerged in the test mixture for -30 seconds. 

An adjuvant was not added to the spray mixture for any of the applications. Samples of carrots 

were collected after the test mixture had dried on the day of application [O DAA (Days After 

Application)] and placed in frozen storage. 

Carrot samples were analyzed for fludioxonil residues using a modified version of the reference 

method "Analytical Method for Determination of CGA-I 73506 in Crops by High Performance 

Liquid Chromatography Including Validation Data," Analytical Method No. AG-597B (PMRA # 

2044023, MRID No. 43960411). The reference method has been reviewed and deemed 

acceptable for data gathering and enforcement purposes (REG 2006-08; Memo, 8/I4/95, S. 

Willett, D20630I). Modifications to the method include analysis using liquid chromatography 

with tandem mass spectroscopy (LC/MS/MS) instead of high-performance liquid 

chromatography with ultraviolet detection (HPLC/UV), using a reverse phase Phenomenex 

Polar-RP column with acetic acid water/methanol phase instead of a normal column with 

MRID No. 49347001 Pagel of 8 

Page 15 of 22
 Fludioxonil/FLD/ Syngenta Canada Inc. /SYZ 

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

 Crop Field Trial/ Residue Decline – Carrot roots 

MRID No. 49347001 Page 2 of 8

hexane/methanol/isopropanol phase, using dichloromethane instead of methyl tert-butyl ether 

(MTBE) for the liquid/liquid partition, and omitting the solid-phase extraction (SPE) clean-up 

steps. The limit of quantitation (LOQ) was set at 0.01 ppm, and the limit of detection (LOD) 

was set at 0.003 ppm. The method was validated prior to sample analysis by spiking untreated 

control samples with 0.01, 0.5, 1.0, 2.0, and 4.0 ppm fludioxonil. All method validation 

recoveries were within the acceptable 70-120% range. Adequacy of the method was confirmed 

by spiking control samples with 0.01 and 1.0 ppm fludioxonil, and determining recoveries 

concurrently with analysis of treated sample sets. All concurrent recoveries were also within the 

acceptable range. Given that all method validation and concurrent recoveries were within the 

acceptable range, Analytical Method No. AG-597B, as modified for the current study, is 

adequate for the determination of fludioxonil residues in this study. 

Carrot samples were stored frozen (≤ -15.6o

C) from sampling to extraction for a maximum of 

162 days. Samples were analyzed for residues within 27 days of extraction. A storage stability 

study was not conducted concurrently with the analytical portion of the residue trial study. Data 

on file indicates that residues of fludioxonil are stable when stored frozen for up to 24 months in 

corn, sorghum, and potato (PMRA # 1189618; Reviewed with S1998-1449; Memo, 8/17/95, S. 

Willett, D216233, MRID No. 43690403). Given that the storage stability has been demonstrated 

in another root crop, the potato, the assumption can be made that fludioxonil residues are stable 

in all root and tuber vegetables for up to 24 months (DIR98-02; Section 5.3.2). Therefore, there 

are no concerns regarding the stability of fludioxonil in this study. 

When carrots were treated with 1 application of fludioxonil at 0.3 g ai/L (0.0025 lbs ai/gal), 

fludioxonil residues ranged from 1.91 to 3.49 ppm for the dip application (TRT 02) and 1.63 to 

2.35 ppm for the drench application (TRT 03). 

STUDY/WAIVER ACCEPTABILITY/DEFICIENCIES/CLARIFICATIONS: 

Under the conditions and parameters used in the study, the field trial residue data are classified 

as scientifically acceptable. 

The acceptability of this study for regulatory purposes is addressed in Canada’s forthcoming 

Evaluation Report and in EPA’s summary memo. 

COMPLIANCE:

Signed and dated Good Laboratory Practice (GLP), Quality Assurance and Data Confidentiality 

statements were provided. The study was conducted in compliance with the Organization for 

Economic Co-operation and Development (OECD) Principles for Good Laboratory Practice 

(GLP) (revision 1997), with the exception of the following: 

 Information on weather records, irrigation records, soil characterization, pH 

measurement, test site history and cultural practices for carrots production, maintenance 

fertilizers and pesticides data, and sample weight measurement were not collected 

according to GLP. 

Page 16 of 22
 Fludioxonil/FLD/ Syngenta Canada Inc. /SYZ 

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

 Crop Field Trial/ Residue Decline – Carrot roots 

MRID No. 49347001 Page 3 of 8

It is the opinion of the Study Director and the Evaluators that the cited deviations did not affect 

the scientific integrity of the study. 

A. BACKGROUND INFORMATION

Fludioxonil is a contact fungicide, which is active through inhibition of protein kinase leading to 

reduced growth and development. 

TABLE A.1. Test Compound Nomenclature.

Compound 

Common name Fludioxonil 

Company experimental name A9859E 

IUPAC name 4-(2,2-difluoro-1,3-benzodioxol-4-yl)pyrrole-3-carbonitrile 

CAS name 4-(2,2-difluoro-1,3-benzodioxol-4-yl)-1H-pyrrole-3-carbonitrile 

CAS # 131341-86-1 

End-use product/(EP) Fludioxonil (Scholar 230 SC) 

TABLE A.2. Physicochemical Properties of Fludioxonil

Parameter Value Reference 

Melting point 199.8 oC e-Pesticide Manual, 

Thirteenth Edition, Version 

3.1 

pH Not indicated 

Density (20oC) 1.54 g/cm3

Water solubility ( 25°C) 1.8 mg/L 

Solvent solubility (g/L at 25°C) Solvent Solubility 

(g/L) 

Acetone 

Ethanol 

Toluene 

n-octanol 

Hexane 

190 

44 

2.7 

20 

0.01 

Vapour pressure at 25°C 3.9 x 10-4 mPa 

Dissociation constant (pKa) pKa1 <0; pK2 c. 14.1 

Octanol/water partition coefficient Log(KOW) 4.12 (25oC) 

UV/visible absorption spectrum Not indicated 

B. EXPERIMENTAL DESIGN

B.1. Study Site Information 

TABLE B.1.1. Trial Site Conditions.

Trial Identification (City, Prov./Year) Soil characteristics 

Type %OM* pH* CEC* 

meq/g 

Trial ID # AAFC08-013R-554 

Berwick1, NS/2009

Sandy Loam 2.3 6.3 10.7 

Trial ID # AAFC08-013R-555 

Abbotsford2, BC/2009 

Sandy Loam 2.2 6.0 5.8 

*These parameters are optional except in cases where their value affects the use pattern for the chemical. 

1 Because this study was conducted as a post-harvest trial, the pesticide was applied in Kentiville, NS although the carrots were

grown in Berwick, NS. 

O

O

F F

N

H

CN

Page 17 of 22
 Fludioxonil/FLD/ Syngenta Canada Inc. /SYZ 

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

 Crop Field Trial/ Residue Decline – Carrot roots 

MRID No. 49347001 Page 4 of 8

2 Because this study was conducted as a post-harvest trial, the pesticide was applied in Summerland, BC although the carrots 

were grown in Abbotsford, BC. 

No weather data was provided for these trials because the trials were conducted indoors with 

post-harvest applications under ambient temperatures and controlled conditions. 

TABLE B.1.2. Study Use Pattern.

Location 

(City, 

Prov./Year) 

Trial ID 

EP1 Application Tank Mix/ 

Treatment Adjuvants 

No. 

Method/ 

Timing 

Total 

Treatment 

Volume (L)

 Rate 

g ai/L 

(lbs 

ai/gal) 

RTI2 (days) Total Rate 

g ai/L 

(lbs ai/gal) 

Trial ID # 

AAFC08-

013R-554 

Kentiville, 

NS/2009 

Fludioxonil 

(Scholar 

230 SC) 

02 Dip/ Postharvest 30 0.3 

(0.0025) 

n/a3 0.3 

(0.0025) 

None 

03 Drench/ 

Postharvest 

5 0.3 

(0.0025) 

n/a 

Trial ID # 

AAFC08-

013R-555 

Summerland, 

BC/2009 

Fludioxonil 

(Scholar 

230 SC) 

02 Dip/ Postharvest 12 0.3 

(0.0025) 

n/a 0.3 

(0.0025) 

None 

03 Drench/ 

Postharvest 

6 0.3 

(0.0025) 

n/a 

1 EP = End-use Product 

2 Retreatment Interval 

3 n/a = not applicable 

TABLE B.1.3. Trial Numbers and Geographical Locations. 

NAFTA 

Growing 

Zones 

Carrots 

Submitted Requested* 

1A 1 -- 

5 -- -- 

5B -- -- 

12 1 -- 

Total 2 2 

* Given that the post-harvest trials are conducted indoors under controlled conditions, the trials can be conducted in any zone

(DIR98-02 section 9.4, point 13). 

B.2. Sample Handling and Preparation

At all test sites, four carrot samples were collected from each treated lot (TRT 02 and TRT 03), 

while two carrot samples were collected from each untreated lot (TRT 01). All samples were 

placed in frozen storage ~4 to 4.5 hours after treatment. Each sample weighed at least 2.0 kg 

(maximum of 3.0 kg) and consisted of 20 carrots. 

The samples were shipped frozen to ALS Laboratory Group (Edmonton, AB) via Fed-Ex for 

residue analysis, where they arrived frozen and in good condition. The samples were stored 

frozen at ≤ -15.6o

C until sample preparation. Samples were prepared by grinding with dry ice in 

a Hobart food grinder while frozen. The macerated samples were then placed in frozen storage 

until extraction. 

Page 18 of 22
 Fludioxonil/FLD/ Syngenta Canada Inc. /SYZ 

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

 Crop Field Trial/ Residue Decline – Carrot roots 

MRID No. 49347001 Page 5 of 8

B.3. Analytical Methodology

Residues of fludioxonil were determined in carrot samples using a modified version of the 

reference method “Analytical Method for Determination of CGA-173506 in Crops by High 

Performance Liquid Chromatography Including Validation Data,” Analytical Method No. AG597B (PMRA # 2044023, MRID No. 43960411). The reference method has been reviewed and 

deemed acceptable for data gathering and enforcement purposes (REG 2006-08). Modifications 

to the method include analysis using LC/MS/MS instead of HPLC/UV, using a reverse phase 

Phenomenex Polar-RP column with acetic acid water/methanol phase instead of a normal 

column with hexane/methanol/isopropanol phase, using dichloromethane instead of methyl tertbutyl ether for the liquid/liquid partition, and omitting the SPE clean-up steps. 

Briefly, residues were extracted by blending a 10g carrot sample with a 150 mL solution of 

acetonitrile (ACN): water (90:10, v/v). The extract was centrifuged, and the supernatant was 

extracted again with 40 mL ACN: water (90:10, v/v). The extracts were combined, adjusted to a 

total volume of 200 mL with ACN: water (90:10, v/v), and concentrated on a rotary evaporator. 

A saturated NaCl solution was added, and the solution was partitioned with dichloromethane. 

The solution was then evaporated to dryness, and the extract was reconstituted in 10 mL ACN 

with 0.1% acetic acid. Residues were then determined using LC/MS/MS. The LOQ was set at 

0.01 ppm, and the LOD was set at 0.003 ppm. 

The method was validated prior to sample analysis by spiking untreated control samples with 

0.01, 0.5, 1.0, 2.0, and 4.0 ppm fludioxonil. All method validation recoveries were within the 

acceptable 70-120% range. Mean method validation recoveries were 98 ± 4%, 86 ± 7%, 84 ± 

6%, 96 ± 6%, and 74 ± 1% in samples spiked with 0.01, 0.5, 1.0, 2.0, and 4.0 ppm fludioxonil, 

respectively. Adequacy of the method was confirmed by spiking control samples with 0.01 and 

1.0 ppm fludioxonil, and determining recoveries concurrently with analysis of treated sample 

sets. All concurrent recoveries were also within the acceptable range. Mean concurrent 

recoveries were 89 ± 15% and 98 ± 10% in samples spiked with 0.01 and 1.0 ppm fludioxonil, 

respectively. Given that all method validation and concurrent recoveries were within the 

acceptable range, Analytical Method No. AG-597B, as modified for the current study, is 

adequate for the determination of fludioxonil residues on carrots in this study. 

C. RESULTS AND DISCUSSION 

Two post-harvest trials were conducted on carrots in Canada in the 2009 growing season. The 

trials were conducted in Zone 1A (Nova Scotia), and 12 (British Columbia). Fludioxonil, 

formulated as a suspension concentrate, was applied once to the carrots post-harvest at a rate of 

0.3 g ai/L (0.0025 lbs ai/gal). Adjuvants were not added to the solution. Samples were collected 

on the day of application after the treatment solution dried. Two treatment regimens were used 

at each test site. The first was a dip application (TRT 02), and the second was a drench 

application (TRT 03). 

Residues of fludioxonil were determined in carrot samples using a modified version of the 

reference method “Analytical Method for Determination of CGA-173506 in Crops by High 

Page 19 of 22
 Fludioxonil/FLD/ Syngenta Canada Inc. /SYZ 

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

 Crop Field Trial/ Residue Decline – Carrot roots 

MRID No. 49347001 Page 6 of 8

Performance Liquid Chromatography Including Validation Data,” Analytical Method No. AG597B (PMRA # 2044023). The reference method has been reviewed and deemed acceptable for 

data gathering and enforcement purposes (REG 2006-08; Memo, 8/14/95, S. Willett, D206301). 

Modifications to the method include analysis using LC/MS/MS instead of HPLC/UV, using a 

reverse phase Phenomenex Polar-RP column with acetic acid water/methanol phase instead of a 

normal column with hexane/methanol/isopropanol phase, using dichloromethane instead of 

methyl tert-butyl ether for the liquid/liquid partition, and omitting the SPE clean-up steps. The 

LOQ was set at 0.01 ppm, and the LOD was set at 0.003 ppm. The method was validated prior 

to sample analysis by spiking untreated control samples with 0.01, 0.5, 1.0, 2.0, and 4.0 ppm 

fludioxonil. All method validation recoveries were within the acceptable 70-120% range (Table 

C.1). Adequacy of the method was confirmed by spiking control samples with 0.01 and 1.0 ppm 

fludioxonil, and determining recoveries concurrently with analysis of treated sample sets. All 

concurrent recoveries were also within the acceptable range. Given that all method validation 

and concurrent recoveries were within the acceptable range, Analytical Method No. AG-597B, 

as modified for the current study, is adequate for the determination of fludioxonil residues in 

carrots in this study. Sample chromatograms were provided for standards, solvent blanks, 

untreated control samples, fortified controls, and treated samples. Overall, the peaks were well 

defined and symmetrical, and untreated controls were free from interference above the 

chromatographic background. In the submitted calibration curves, detector linearity was 

demonstrated over a 6-point range of 1.00-40.0 ng/mL (R2 ≥ 0.9970). 

Carrot samples were stored frozen (≤ -15.6 oC) from sample collection to extraction for a 

maximum of 162 days (Table C.2). Samples were analyzed for residues within 9 to 27 days of 

extraction. A storage stability study was not conducted concurrently with the analytical portion 

of the residue trial study. Data on file indicate that residues of fludioxonil are stable when stored 

frozen for up to 24 months in corn, sorghum, and potato (PMRA # 1189618; Reviewed with 

S1998-1449; Memo, 8/17/95, S. Willett, D216233, MRID No. 43690403). Given that the 

storage stability has been demonstrated in another root crop, the potato, the assumption can be 

made that fludioxonil residues are stable in all root and tuber vegetables for up to 24 months 

(DIR98-02; Section 5.3.2). Therefore, there are no concerns regarding the storage stability of 

fludioxonil in this study. 

When carrots were treated with 1 application of fludioxonil at 0.3 g ai/L (0.0025 lbs ai/gal), 

fludioxonil residues ranged from 1.91 to 3.49 ppm for the dip application (TRT 02) and 1.63 to 

2.35 ppm for the drench application (TRT 03) (Table C.3 and C.4). 

 

Page 20 of 22
 Fludioxonil/FLD/ Syngenta Canada Inc. /SYZ 

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

 Crop Field Trial/ Residue Decline – Carrot roots 

MRID No. 49347001 Page 7 of 8

TABLE C.1. Summary of Method Validation and Concurrent Recoveries of Fludioxonil from Carrots.

Matrix Recovery 

Type 

Spike 

level 

(ppm) 

Sample size 

 (n) 

Recoveries 

 (%) 

Mean ± std dev 

(%) 

Fludioxonil 

Carrots Method 

Validation 

0.01 3 102, 98.4, 94.8 98 ± 4 

0.5 3 78.3, 86.3, 93.2 86 ± 7 

1.0 3 78.0, 88.8, 86.2 84 ± 6 

2.0 3 88.8, 99.3, 100 96 ± 6 

4.0 3 72.8, 74.5, 73.8 74 ± 1 

Concurrent 

Recovery 

0.01 9 95.9, 81.8, 86.9, 126*, 

82.7*, 86.1, 76.2, 79.3, 

81.6* 

89 ± 15 

1.0 3 110*, 94.0, 91.0 98 ± 10 

* Average of duplicate analysis 

TABLE C.2. Summary of Storage Conditions.

Matrix 

(RAC) 

Storage Temperature 

 (°C) 

Actual Storage 

Duration (days) 

Interval of Demonstrated Storage Stability 

 (months) 

Carrots -31 to -15.6 162 days* A storage stability study was not conducted with the 

analytical portion of the residue trial. Data on file 

indicates residues of fludioxonil are stable when 

stored frozen for up to 24 months in corn, sorghum, 

and potato (PMRA # 1189618; Reviewed with 

S1998-1449; Memo, 8/17/95, S. Willett, D216233, 

MRID No. 43690403). Given that storage stability 

data has been demonstrated in a root crop, the potato, 

the assumption can be made that residues are stable in 

all root and tuber vegetables for up to 24 months 

(DIR98-02; Section 5.3.2). 

* Longest storage duration of any sample from time of sampling to extraction. Samples were analyzed within 9 and 27 days of 

extraction. 

TABLE C.3. Residue Data from Crop Field Trials with Fludioxonil.

Trial ID 

(City, 

Prov./Year) 

Zone Crop/ 

Variety 

Commodity Total Rate 

g ai/L 

(lbs ai/gal) 

DAA1

(days) 

Application 

Method 

Residues (ppm) 

[Average] 

Trial ID # 

AAFC08-

013R-554 

Kentiville, 

NS/2009 

1A Carrot/ 

Pronto 

Carrot 

(roots) 

0.3 

(0.0025) 

0 Dip 

[TRT 02] 

3.49 

2.61 

2.30 

1.94 

[2.59] 

0.3 

(0.0025) 

0 Drench 

[TRT 03] 

2.07 

2.04 

1.79 

1.63 

[1.88] 

Trial ID # 

AAFC08-

013R-555 

Summerland 

BC/2009 

12 Carrot/ 

Bolero 

Carrot 

(roots) 

0.3 

(0.0025) 

0 Dip 

[TRT 02] 

2.96 

2.55 

2.31 

1.91 

[2.43] 

0.3 

(0.0025) 

0 Drench 

[TRT 03] 

2.01 

1.81 

2.35 

1.87 

[2.01] 

Page 21 of 22
 Fludioxonil/FLD/ Syngenta Canada Inc. /SYZ 

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

 Crop Field Trial/ Residue Decline – Carrot roots 

MRID No. 49347001 Page 8 of 8

1 DAA = Days After Application. 

TABLE C.4. Summary of Residue Data from Crop Field Trials with Fludioxonil.

Commodity Total Applic. 

Rate 

g ai/L 

(lbs ai/gal) 

DAA 

(days) 

Residue Levels (ppm) 

n Min. Max. HAFT1 LAFT2 Median 

(STMdR) 

Mean 

(STMR) 

Std. Dev.

TRT 02 (Dip) 

Carrot roots 0.3 

(0.0025) 

0 8 1.91 3.49 -- -- 2.43 2.51 0.53 

2 -- -- 2.59 2.43 2.51 2.51 -- 

TRT 03 (Drench) 

Carrot roots 0.3 

(0.0025) 

0 8 1.63 2.35 -- -- 1.94 1.95 0.22 

2 -- -- 2.01 1.88 1.95 1.95 -- 1 HAFT = Highest Average Field Trial. 

2 LAFT = Lowest Average Field Trial. 

D. CONCLUSION 

The supervised crop field trials for fludioxonil on carrots are considered scientifically valid. 

Two post-harvest trials were conducted on carrots in Zone 1A and 12. Fludioxonil was applied 

once to the carrots post-harvest at a rate of 0.3 g ai/L (0.0025 lbs ai/gal). Residues of fludioxonil 

ranged from 1.91 to 3.49 ppm for the dip application (TRT 02) and 1.63 to 2.35 ppm for the 

drench application (TRT 03). 

E. REFERENCES

PMRA # 1189618. MRID No. 43690403. Eudy, L.W. (1997) “Stability of CGA-173506 

Fortified into Corn, Sorghum, and Potato Substrates under Freezer Storage Conditions.” Report 

No. ABR-97108. Study No. 115-93. Unpublished study prepared by Novartis Crop Production 

Inc., Greensboro, USA. 78 pages. 

PMRA # 2044023. MRID No. 43960411. Campbell, D.D. (1996) “Analytical Method for the 

determination of CGA-173506 in Crops by High Performance Liquid Chromatography Including 

Validation Data.” Analytical Method No. AG-597B. Protocol No. 56-92. Project No. 426982. 

Unpublished study prepared by Ciba-Geigy Corporation, Greensboro, USA. 112 pages. 

F. DOCUMENT TRACKING

Not Applicable. 

Template Version June 2005.

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