UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

WASHINGTON, D.C. 20460 

MEMORANDUM 

Date: 05-May-2015 

OFFICE OF 

CHEMICAL SAFETY AND 

POLLUTION PREVENTION 

Subject: Prohexadione Calcium. Section 3 Registration for Use on Strawberry and 

Watercress. Summary of Analytical Chemistry and Residue Data. 

PC Code: I 12600 DP Barcode: 0419981 

Decision No.: 489681 Re istration No.: 7969-188 

Petition No.: 4E8264 Re ulator Action: Section 3 

Risk Assessment Ty e: NA Case No.: 7030 

TXR No.: NA CAS No.: 127277-53-6 

MRID Nos.: 4933900 I, 49339002 40 CFR: §180.547 

From: William 0. Wassell, Chemist 

Risk Assessment Branch I (RAB l) 

Health Effects Division (HED; 7509P) 

Through: George F. Kramer, Ph.D., Branch Senior Chemist ~41-t~~~~~~-a=:;;z_ __ 

RAB 1/HED (7509P) 

To: Barbara Madden/Laura Noll en, RM 05 

Registration Division (RD; 7505P) 

Executive Summary 

Prohexadione calcium [calcium 3-oxido-5-oxo-4-propionylcyclohex-3-enecarboxylate) is a plant 

growth regulator proposed for use by the Interregional Research Project No. 4 (IR-4) on 

strawberry and watercress. The product reduces vegetative growth, shoot growth, and produces 

a larger stem diameter (watercress). Prohexadione calcium works by inhibiting the biosynthesis 

of gibberellins, resulting in a decrease in cell elongation and a slowing .of cell growth. Shoot 

reduction may cause positive benefits such as better light penetration, better fruit coloring, and 

better air flow within the plants. For watercress, prohexadione calcium may suppress growth for 

up to 14 days. For strawberries, vegetative growth suppression lasts for 2 to 5 weeks after 

application and does not affect vegetative growth the following year. The registered product, 

Apogee® Plant Growth Regulator (EPA Reg. No. 7969-188), is formulated as a wettable granule 

(WG) containing 27.5% prohexadione calcium. 

Tolerances are currently established under 40 CFR §I 80.547(a) for residues of prohexadione 

calcium inion pome fruit, peanut, grass, cherry, and livestock commodities at levels ranging from 

0.05 to 3.5 ppm. 

Page I of 13 
Prohexadione Calcium DP#: 4 19981 

The proposed tolerances for residues of prohexadione calcium are: 

Strawberry .......... ....... ....... ..... ........ .... ..... .... ........ ...... 0.3 ppm 

Watercress ................................................................ 2 ppm 

Based on apple and peanut metabolism studies, the HED Metabolism Assessment Review 

Committee (MARC) concluded that for these crops parent compound is the only residue of 

concern for the tolerance expression and dietary risk assessment (Memo, G. Kramer, 4/07/00; 

DP# 263502). HED concludes that this decision may be translated to strawberry and watercress. 

For enforcement of tolerances for prohexadione calcium in pome fruit, grass, peanut, and 

li vestock commodities (registered uses), the petitioner used a residue analytical method (BASF 

Method 0 9601) using gas chromatograph equipped with a mass-selective detector (GC/MSD). 

The method was designed to measure residues of prohexadione calcium as the prohexadione 

methyl ester. The reported level of quantitation (LOQ) for prohexadione calcium is 0.05 ppm for 

all apple, pear, and peanut commodities. The method was successfully validated by the Agency 

Analytical Chemistry Laboratories (ACL) at Fort Meade. Additionally, BASF Method 564/0 has 

been proposed for enforcement of prohexadione tolerances in/on cherries. The extraction of 

residues are performed in the same manner as that of BASF Method No. 09601 . The final 

detem1ination of prohexadione calcium is performed by liquid chromatography equipped with 

tandem mass spectrometers (LC-MS/MS). The LOQ for residues in cherries is 0.0 I ppm. This 

method has been deemed adequate for enforcement of tolerances for residues in cherries. 

BASF Analytical Method 0960 I, with minor modifications, was utilized for the determination of 

residues of prohexadione calcium in watercress samples. The method was validated prior to and 

in conjunction with the analysis of treated samples. The LOQ was validated to be 0.1 ppn1 for 

residues in watercress. BASF Method 564/0 was utilized for the determination of residues of 

prohexadione calcium in strawberry samples. The method was validated prior to and in 

conjunction with the analysis of treated samples. The LOQ was validated to be 0.0 I ppm for 

residues in strawberry. HEO has determined that BASF Analytical Method 0 960 l is adequate 

for the determination of residues of prohexadione calcium in/on watercress and Method 564/0 is 

adequate for the determination of residues of prohexadione calcium in/on strawberries. 

Adequate crop field trial data are available for prohexadione calcium on strawberry and 

watercress. Based on the results of these trials, the appropriate tolerance for residues of 

prohexadione calcium in/on strawberry is 0.3 ppm and in/on watercress is 4.0 ppm. A revised 

Section F is required. 

Regulatory Recommendations and Residue Chemistry Deficiencies 

Pending submission of revised Section F (see requirements under Proposed Tolerances) and an 

analytical-grade standard (see requirements under Submittal of Analytical Reference Standards), 

there are no residue chemistry issues that would preclude establishment of unconditional 

registrations and the following pennanent tolerances for the growth regulator, prohexadione 

calcium, including its metabolites and degradates, in or on the commodities in the table below. 

Compliance with the tolerance levels specified below is to be determined by measuring only 

prohexadione calcium (calcium 3-oxido-5-oxo-4-propionylcyclohex-3-enecarboxylate), in or on 

the following commodities: 

Page 2of13 
Prohexadione Calcium DP#: 419981 

Strawberry ................................................... ....... ...... 0.30 ppm 

Watercress ................................................................ 4.0 pp1n 

860.1550 Proposed Tolerances 

• The petitioner should submit a revised Section F reflecting the I-JED-recommended 

tolerance level specified above for residues in/on watercress. 

860.1650 Submittal of Analytical Reference Standards 

• The analytical reference standard for prohexadione calcium has expired (personal 

communication with Theresa Cole, Analytical Chemistry Branch (ACB), 1230/20 14). 

The registrant must either recertify the lot in the repository and send in an updated 

Certificate of Analysis (COA), or submit new standards (different lot #) if the previous 

lots will not be recertified. 

If new standards are being submitted, they should be sent to ACB, which is located at 

Fort Meade, to the attention of either Theresa Cole at the fo llowing address: 

USEPA 

National Pesticide Standards Repository/Analytical Chemistry Branch/OPP 

701 Mapes Road 

Fort George G. Meade, MD 20755-5350 

(Note that the mail will be returned if the extended zip code is not used.) 

A human health risk assessment is forthcoming in a separate document. 

Background 

Prohexadione calcium is a plant growth regulator that works by inhibiting the biosynthesis of 

gibberellins, resulting in a decrease in cell elongation and a slowing of cell growth. The 

chemical structure and nomenclature of prohexadione calcium is presented in Table 1. The 

physicochemical properties of the technical grade of prohexadione calcium are presented in 

Table 2. 

Page 3of13 
Prohexadione Calcium DP#: 419981 

Table I. Test Compound Nomenclature. 

Compound ~ - - 0 

~ 

Cll1 

cl• - a 

0 

0 

0 

- -

Common name Prohcxadione calcium 

Company experimental name BAS 125 W 

IUPAC name calcium 3-oxido-5-oxo-4-propionylcyclohex-3-enccarboxylatc 

CJ\S name calcium 3-oxido-5-oxo-4-propionylcyclohex-3-enccarboxylate 

CJ\S registry number 127277-53-6 

End-use product (EP) Apogee® Plant Growth Regulator (EPA Reg. No. 7969-188) 

Table 2. Physicochemical Properties of Prohexadione Calcium. 

Parameter Value Reference 

Water solubility (20°C for 96.6% 174 mg/Lin distilled water, 1602 mg/L in pll 5 Memo, H. Podall, 5/18/99. 0253852 

pure sample) bufTer. 786 mg/L in pl I 7 bufTcr. and 665 mg/L 

in pll 9 buffer 

Solvent solubility (20°C for 0.038 mg/L in acetone 

96.6% pure sample) 0.004 mg/L in toluen..: 

I. 11 mg/L in methanol 

0. 105 mg/Lin isopropanol 

<0.003 mg/L in n-hexanc 

Vapor pressure 1.00 x JO·' torr at 20 °C 

Dissociation constant pK. 5.15 

Octanol/watcr partition coefficient log P = -2.9 at 20 •c, pH 7 l1ttQ://sitem.hcrts.ac.uk/acru!footQrint/cn 

/Regorts/539.htm 

860.1200 Directions for Use 

Currently, prohexadione calcium is registered for use on pome fruit, peanut, grass, and cherry as 

a plant growth regulator. IR-4 has proposed to register Apogee® Plant Growth Regulator (EPA 

Reg. No. 7969-188) for use on strawberries and watercress. Information pertaining to the 

registered/proposed end-use product is presented in Table 3. A summary of the proposed use 

patterns is presented in Table 4. 

Page 4of13 
Prohexadione Calcium DP#: 419981 

Table 3. Summary of Registered/Proposed End-Use Products. 

Prohexadione 

EPA File Calcium Fomrnlation 

Trade Name Symbol No. Concentration Type Target Crops Target Pests Label Date 

Apogee® Strawberry Plant Growth 7969- 188 27.5% WG NA None 

Regulator Watercress 

Table 4. Summary of Proposed Directions for Use of Prohexadione Calcium. 

Applic. Timing, Trade Name; Max. No. Max. Seasonal 

Type, and Formulation Applic. Rate Applic. per Applic. Rate PHI 

Equipment [EPA Reg. No.] (lbai/A) Season (lb ai/A) (days) 

Strawberry 

Foliar application with 

ground equipment. 

When 80 to 100% ofthe Apogee® Plant 

plants have 5 fully Growth Regulator 0.034 3 1.02 21 expanded leaves and 27.5% WG 

before plants show first (7969-188] 

sign of runner 

formation. 

Use Directions and Limitations: Do not apply with airblast equipment or by airplane. Use a minimum of IO 

gallons of spray solution per acre per application. Applications may be made at intervals of 14 to 21 days. Use a 

standard spray adjuvant, preferably a non-ionic surfactant. 

Watercress 

Foliar with ground or 

sprinkler irrigation Apogee"" Plant systems. Apply when 

watercress has leafed up 

Growth Regulator 0.1375 2 0.275 3 27.5% WG from the previous (7969-188) harvest (5 to I 0 days). 

Use Directions and Limitations: Apply ground applications through properly calibrated airblast equipment using 

a volume of I 00 gallons per acre. Chemigation applications must be made as concentrated as possible. For best 

results apply at 0.1 inch up to 0.15 inch (2,716 to 4,073 gallons) of water per acre. A second application may be 

made 7 days after the first application. Do not tank mix with any other pesticide products, adjuvants, liquid 

ferti lizer, nutrients, any other additives or anything other than water. 

Conclusions: The submitted use directions for Apogee® Plant Growth Regulator are adequate to 

allow evaluation of the residue data relative to the proposed uses. 

860.1300 Nature of the Residue - Plants 

Memo, 11 /22/99, G. Kramer, D252547 

Based on apple and peanut metabolism studies, the HED MARC concluded that for these crops 

parent compound is the only residue of concern for the tolerance expression and dietary risk 

assessment (Memo, G. Kramer, 4/07/00; OP# 263502). Prohexadione calcium is rapidly 

metabolized to prohexadione and parent-like oxidative intermediates and ultimately to 

tricarballylic acid, citric acid, and other natural products from the plant carbon pool. HED 

concludes that this decision may be translated to strawberry and watercress. 

Page 5of13 
Prohexadione Calcium DP#: 419981 

860.1300 Nature of the Residue -Livestock 

Data requirements regarding this guideline topic are not germane to this petition because there 

are no feedstuffs associated with the proposed uses on strawberry and watercress. 

860.1340 Residue Analytical Methods 

DER Reference: 4810670 l .der.doc 

Memo, 0311 0/200 I, G. Kramer, D2735 I 0 

Memo, 06/02/20 1 I, G. Kramer, D384706 

Existing Enforcement Methods: For enforcement of tolerances for prohexadione calcium in 

pome fruit, grass, and peanut commodities (registered uses), the petitioner used a residue 

analytical method (BASF Method 0 960 1) using GC/MSD. The method was designed to 

measure residues of prohcxadione calcium as the prohexadione methyl ester. The reported LOQ 

for prohexadione calcium is 0.05 ppm for all apple, pear, and peanut commodities. The method 

was successfully va lidated by the Agency ACL in Fort Meade. Additionally, BASF Method 

564/0 has been proposed for enforcement of prohexadione tolerances in/on cherries (registered 

use). The extraction of residues are performed in the same manner as that of BASF Method No. 

D9601. The final determination of prohexadione calcium is performed by LC-MS/MS. The 

LOQ for residues in cherries is 0.0 1 ppm. This method has been deemed adequate for 

enforcement of tolerances for residues in cherries. 

BASF Analyti cal Method D960 1, with minor modifications, was utilized for the determination of 

residues of prohexadione calcium in watercress samples. The method was validated prior to and 

in conjunction with the analysis of treated samples. The LOQ was validated to be 0.1 ppm for 

residues in watercress. For method validation, fortifications ranged from 0.1 to 5.0 ppm with an 

average recovery of 74 ± 3% (n= 9). For concurrent recoveries, fortification levels ranged from 

0.1 to 5.0 ppm with an average recovery of 80 ± 5% (n= 9). 

BASF Method 564/0 was utilized for the determination of residues of prohexadione calcium in 

strawberry samples. The method was validated prior to and in conjunction with the analysis of 

treated samples. The LOQ was validated to be 0.01 ppm for residues in strawbeny. For method 

validation, fortifications ranged from 0.0 1 to l.O ppm with an average recovery of 87 ± 9% (n= 

9). For concurrent recoveries, fortification levels ranged from O. l to 1.0 ppm with an average 

recovery of 92 ± 11 % (n= 18). 

Conclusions: HED has detennined that BASF Analytical Method D960 1 is adequate for the 

determination of residues of prohexadione calcium in/on watercress and Method 564/0 is 

adequate for the determination of residues of prohexadione calcium in/on strawberries. 

860.1360 Multiresi<.lue Methods 

Memo, 06/02/20 11, G. Kramer, D384706 

Memo, G. Kramer, 11 /30/99; DP# 257930 

The petitioner has previously submitted data concerning the recovery of residues of 

prohexadione and its despropionyl metabolite using FDA Multi residue Method protocols (PAM 

Vol. I). These data were forwarded to FDA for a complete evaluation (Memo, G. Kramer, 

l l/30/99; DP# 257930). The petitioner reported that residues of prohexadione and the 

despropionyl metabolite are not recovered using FDA Multiresidue Method protocols. 

Page 6of13 
Prohexadione Calcium DP#: 419981 

Additionally, the QuEChERS method has not been shown to adequately quantify residues of 

prohexadione calcium. 

(http://www.crl-pcsticidcs.eu/I i brarv/docs/fv/CRLFV Mui l i residue methods. pd Q. 

860.1380 Storage Stability 

DER Reference: 4933900 I .der.doc (strawberry) 

DER Reference: 49339002.der.doc (watercress) 

The maximum frozen storage intervals from harvest to analysis for strawberry samples was 390 

days (- I3 months) and for watercress samples was 794 days (-26 months). Storage stabi lity 

data for prohexadione calcium in/on watercress and strawberry were generated in conjunction 

with the crop field trials. The data demonstrate that residues inion strawberries are stable for up 

to 422 days (-14 months); however, the data indicate residues in/on watercress declined by about 

34% during frozen storage. These data are adequate to support the storage conditions and 

durations of samples from the current studies. Residue data for watercress were adjusted for 

degradation during storage. 

860.1480 Meat, Milk, Poultry, and Eggs 

There are no livestock feedstuffs associated with the crops addressed herein. Therefore, data 

requirements pertaining to meat, milk, poultry, and eggs are not relevant to this tolerance 

petition. 

860. l 500 Crop Field Trials 

DER Reference: 4933900 I .der.doc (strawberry) 

DER Reference: 49339002.der.doc (watercress) 

Strawberry: 

Nine field trials for prohexadione calcium on strawberries were conducted in Canada and the 

United States encompassing North American Free Trade Agreement (NAFT A) Growing Regions 

IA ( 1 in NS), 2 ( I in NJ), 3 ( I in FL), S (I in ON), SA (l in MI), SB (I in QC), IO (2 in CA), and 

12 (l BC) during the 20 I 0 and 20 11 growing seasons. 

At each trial location, prohexadione calcium, formulated as a WG, was applied to strawberries as 

three foliar applications. The rates ranged from 36.0 g ai/ha (0.032 1 lbs ai/ A) to 40.8 g ai/ha 

(0.0364 lbs ai/A), the re-treatment intervals (RTis) were 8- 15 days, and the total application rate 

was 110 g ai/ha (0.0990 lbs ai/A). For each application, a non-ioni c surfactant was added in the 

spray mixture at a 0.05% (v/v) rate and ammonium sulfate was added at a l: 1 ratio. Strawberries 

were harvested at preharvest intervals (PHls) of 16-25 days. In one trial (# 12 1), samples were 

collected at different time intervals (PHis of 13, 19, 26, 31 days) to assess residue decline. 

Individual sample (and per-trial average) residues in strawberries ranged from 0.03 ppm to 0.1 6 

ppm (0.03 ppm to 0.15 ppm). Residue decline data show that residues of prohexadione calcium 

decrease in strawberries with increasing PHls. 

Page 7of 13 
Prohexadione Calcium DP#: 419981 

Table 5. Summarv o f Residues from Strawberry Field Trials with Prohexad ione Calcium. 

Total Residues (oom) 

Crop Application PHI 

Matrix Analyte Rate (days) N Min.

1 Max. 1 LAFT2 HAFT2 Median 2 Mean2 so2 

[g ai/ha) 

(lbs ai/A) 

Strawberry Prohexadione 111-11 6 

(0.0990- 16-25 9 0.03 0. 16 0.03 0. 15 0.06 O.o? 0.038 fruit calcium 0. 104) 1 Values based on total number of samples. 2 Values based on per-trial averages. LAFT = lowest average field trial. I IAFT = highest average field trial, SD = standard 

deviation. 

n = number of field trials. 

Conclusions: The submitted field trial data for strawberry are adequate to fulfill data 

requirements. The number and locations of the trials are in accordance with OPPTS Guideline 

860.1500 (Table 6). 

Ta ble 6. Tria l Numbers a nd Geographica l Locations. 

Crop No. Trials NAFT A Growing Zone Total 

I IA 2 3 4 5 5/\ SB 6 7 8 9 10 11 12 

Straw- Submitted I I I 2 I 2 I 9 

berry Req. u.s.1 Il l 110 Il l 111 3/2 Ill 816 

Req. Can.2 I I I I I 5 1 As per Table 5 of 860.1500 for strawberry: the second number reOects a 25% reduction in the number of field trials allowed for 

the crop as a representative commodity in support of a crop group/subgroup tolerance or when application results in no 

quantifiable residues. 2 As per Table 1.2 of PMRA Regulatory Directive DIR20 10-05. 

The residue data for strawberry were entered into the Organization for Economic Co-operation 

and Development (OECD) maximum residue limit (MRL) Calculator. Based on the results of 

these trials, the appropriate tolerance for residues of prohexadione calcium inion strawberry is 

0.30 ppm. 

Watercress: 

The IR-4 has submitted field trial data for prohexadione calcium on watercress from three field 

trials conducted in the United States during the 2009 growing seasons in the NAFTA Growing 

Zones 2 (MO; 1 trial) and 3 (FL; 2 trials). 

Each trial consisted of one untreated plot and one treated plot (pond) with the exception of Trial 

FL24, which had two treated plots set up in different ponds. For purposes of this review, the 

second plot will be treated as a separate trial herein. At each trial one treated plot received four 

foliar broadcast applications of a 27.5% WO formulation of prohexadione calcium (Apogee® 

Plant Growth Regulator) at 0.135-0. 143 lb ai/ A/application, with two applications each made 

before the first and second cuttings for total rates of 0.272-0.284 lb ai/A for each cutting. After 

the first harvest, the watercress was cut and allowed to regrow before the second set of 

applications. At Trial FL24, a second treated plot received four fo liar overhead chemigation 

applications at 0.140 lb ai/ A/application as above for total rates of 0.280 lb ai/ A for each cutting. 

The spray mixtures for the chemigation applications also included a tebuconazole end-use 

product as part of another study. Data and information pertaining to tebuconazole are not 

addressed further in this summary document. Applications were made at RTis of 6-7 days 

between first and second and third and fou11h applications; RTis were 15-24 days bet\.veen the 

second and third applications. Applications were made in spray volumes of 29.4-59.2 gal/A 

Page 8of 13 
Prohexadione Calcium DP#: 41998 1 

using ground equipment for foliar broadcast applications and in spray volumes of l 06.8-250.5 

gal/A for chemigation applications. A nonionic surfactant (NlS) was added to the spray mixture 

for all applications. Samples of watercress from each cutting were harvested at maturity at a 3-

day PHI. 

In watercress harvested at the proposed PHI of 3 days fo llowing the last of two broadcast fo li ar 

or four chemigation applications of the 27.5% WG formulation of prohexadione calcium at a 

total rate of 0.272-0.284 lb ai/A, individual sample (and per-trial average) residues of 

prohexadione calcium were 0.298-2.00 (0.32 1- 1.72) ppm. Residues were generally lower in 

second-harvest samples than they were in first-harvest samples, and residues were lower 

followi ng chemigation applications than they were following foliar applications: overall average 

residues were 0.347 ppm following chemigation applications vs. 1.30 ppm following foliar 

applications. Residue decline was not evaluated. 

Table 7. Summary of Residues from Watercr ess Field T rials wit h Prohexaclione Calcium. 

Total Application Piii Residues (ppm Prohexadione calcium) 

Crop Matrix Rate (lb ai/A) (days) n' Min.

2 Max.2 LAfT1 HAFT3 Mcdian3 Mean3 

As Found 

Watercress. I" cutting 0.272-0.284 3 3 0.203 1.32 0.2 12 1.14 0.933 0.760 

Watercress, 2nd cutting 0.277-0.280 3 3 0. 197 0.725 0.246 0.7 11 0.654 0.537 

Watercress combined 0.272-0.284 3 3 0. 197 1.32 0.212 1.1.t 0.683 0.649 

Corrected for Decline in Storage 

Watercress. I •

1 cutting 0.272-0.284 3 3 0.307 2.00 0.32 1 1.72 1.41 1.15 

Watercress, 2"d cutting 0.277-0.280 3 3 0.298 I. I 0 0.373 1.08 0.991 0.8 14 

Wntercrcss combined 0.272-0.284 3 3 0.298 2.00 0.32 1 1.72 1.03 0.983 1 n = number or field trials. 2 Values based on total number or samples. 3 Values based on per-trial averages. LAFT = lowest average field trial. I IAFT =highest average field trial, SD= standard 

deviation. 

SD3 

0.486 

0.253 

0.367 

0.736 

0.384 

0.557 

Conclusions: The submitted field trial data for watercress are adequate to fulfill data 

requirements. The number and locations of the trials are in accordance with OPPTS Guideline 

860. 1500 (Table 6). 

Ta ble 8. T ria l Numbers a nd Geograph ica l Locations. 

0. NAFT A Growing Zone 

Crop Trials I 2 3 4 5 6 7 8 9 10 11 12 

Watercress Sub. I 2 

Rcq. 1 

1 As per fab le I of 860.1500. Geographic distribution 1s not speci lied for crops requiring three or fewer trials. 

The residue data for watercress were entered into the OECD MRL Calculator. Based on the 

results of these trials, the appropriate tolerance for residues of prohexadione calcium in/on 

watercress is 4.0 ppm. 

860.1520 Processed Food and Feed 

Total 

3 

2 

There is no crop associated with this petition for whi ch HED requires residue data for processed 

fractions. 

Page 9of1 3 
Prohexadione Calcium DP#: 419981 

860.1650 Submittal of Analytical Reference Standards 

The analytical reference standard for prohexadione calcium has expired (personal 

communication with Theresa Cole, ACB, 12/30/2014). The registrant must either recertify the 

lot in the repository and send in an updated COA, or submit new standards (different lot#) if the 

previous lots will not be recertified. 

If new standards are being submitted, they should be sent to the ACL, which is located at Fort 

Meade, to the attention of either Theresa Cole at the following address: 

USEPA 

National Pestic ide Standards Repository/ Analytical Chemistry Branch/OPP 

70 I Mapes Road 

Fort George G. Meade, MD 20755-5350 

(Note that the mail will be returned if the extended zip code is not used.) 

860.1850/860.1900 Confined/Field Accumulation in Rotational Crops 

Rotational crop studies are not germane to this petition as the proposed crops are not rotated with 

other crops. 

860.1550 Proposed Tolerances 

Tolerances are currently established under 40 CFR § l 80.547(a) for residues of prohexadione 

calcium in/on pome fruit, peanut, grass, and livestock commodities at levels ranging from 0.05 to 

3.5 ppm. HED concludes 40 CFR § l 80.547(a) should be revised to include the following 

tolerances: 

Table 9. Tolerance Summa r 1 for Prohexadione Calcium. 

Commodity Proposed HED-Recommendcd Correct Commodity Definition Tolerance (ppm) Tolerance (ppm) 

Strawberry 0.3 0.3 

Watercress 2 4 

A revised Section F is required to revised the requested tolerance level for residues in/on 

watercress. 

An International Residue Limit (IRL) Status Fonn is appended to this document. There are 

currently no established Codex, Canadian, or Mexican MRLs for prohexadione calcium in/on 

strawberries and watercress. The use on strawberry is a joint review between the U.S. EPA and 

Health Canada Pest Management Regulatory Agency (PMRA). The tolerance expression and 

level for prohexadione calcium in/on strawberry is harmonized with PMRA. 

cc: W. Wassell (RAB I) 

ROI: RABI Chemists(Ol /07/20 15) 

Template Version September 2005 

Page 10of13 
Prohexadione Calcium DP#: 419981 

Appendix I. International Residue Limit (IRL) Status Form 

Prohexadione Calc ium (112600; 12/29/2014) 

Summary of US and International Tolerances and Maximum Residue Limits 

Residue Definition: 

us Canada Mexico2 Codex 

40 CFR §180.547 calcium 3,5-dioxo-4-( I- None 

Plant/Livestock: oxopropyl)cyclohexanccarboxyla 

calcium 3-oxido-5-oxo-4- te 

propionylcyclohex-3-

enecarboxylate 

Commodity 1 Tolerance (pom) /Mcui11111111 Residue limit (m f!/kf!.) 

us Canada Mexico2 Codex 

Strawberry 0.3 

Watercress 4.0 

Completed: M. Negussie; 12/30/1 4 1 Includes only commodities of mterest 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. 

Page 11 of 13 
Prohexadione Calcium 

Appendix II. Tolerance-Assessment Calculations. 

Prohexadione 

Strawberry 

Foliar application 

0.0321 - 0.0364 lbs ai/A (36 - 41 g ai/ha) 

Total nwnber of data (n) 

Percentage of censored data 

Nwnber of non- censored data 

Lowest residue (LR) 

Highest residue (HR) 

Median residue (STMR) 

Mean 

Standard deviation (SD) 

Correction factor for censoring (CF) 

Proposed MRL estimate 

Unrounded 

Rounded to the next MRL class 

Prohexadione 

Strawberry 

Foliar application 

0.0321 - 0.0364 lbs ai/A (36 - 41 g ai/ha) 

Residues (mg/kg) 

0 . 040 

0 . 090 

0.080 

0.100 

0 . 040 

0 . 060 

0 . 050 

0 . 150 

0.030 

0.070 

Page 12of 13 

DPll: 419981 

10 

0% 

10 

0.030 

0.150 

0.06 5 

0 . 071 

0 . 03 6 

1 . 000 

0.21 5 

0.3 
Prohexadione Calcium 

Total number of data (n) 

Percentage of censored data 

Number of non-censored data 

Lowest residue (LR) 

Highest residue (HR) 

Median residue (STMR) 

Mean 

Standard deviation (SD) 

Prohexadione 

Watercress 

Foliar application 

Total Rate: 0.272-0.284 lb ai/A 

Correction factor for censoring (CF) 

Proposed MRL e stimate 

Unrounded 

Rounded to the next MRL class 

High uncertainty of MRL estimate due to small dataset . 

Prohexadione 

Watercress 

Foliar application 

Total Rate: 0.272-0.284 lb ai/A 

Residues (mg/kg) 

1. 720 

0.991 

0 . 321 

0.373 

1.410 

1. 080 

Page 13of 13 

DP#: 419981 

6 

0% 

6 

0 . 321 

1 . 720 

1. 036 

0 . 983 

0.556 

1 . 000 

3 . 206 

4 
Prohexadionc calcium [PC Code I I 2600]ffhe Interregional Research Project No. 4 (IR-4) [BAS 125 W] 

05-May-2015 

B.7.6 

B.7.6. J 

B.7.6.1.2 

Document ID: 

Report: 

Guidelines: 

Residues Resulting from Supervised Trials 

(Annex IIA 6.3; Annex IIIA 8.3) 

Residues in Target Crops 

Waterc ress 

MRID No. 49339002 

Corley, J. (2012) Prohexadione Calciwn: Magnitude of the Residue on 

Watercress. IR-4 Study Number: 101 5 1. Unpublished study prepared by 

IR-4. 164 p. 

EPA OCSPP Harmonized Test Guideline 860.1500 Crop Field Trials 

(August 1996) 

PMRA Regulatory Directive DIR98-02 - Residue Chemistry Guidelines, 

Section 9 - Crop Field Trials 

PMRA Regulatory Directive DIR2010-05 - Revisions to the Residue 

Chemistry Crop Field Trial Requirements 

OECD Guideline 509 Crop Field Trial (September 2009) 

GLP Compliance: No deviations from regul atory requirements (Good Laboratory Practice 

Requirements of 40 CFR § 160) were reported which would have an 

impact on the validity of the study. 

Acceptability: 

Evaluator: 

The study is considered scientifically acceptable. The acceptability of this 

study for regulatory purposes is addressed in the forthcoming U.S. EPA 

Residue Chemistry Summary Document, DP# 419981. 

William D. Wassell, mi,Jf~Jf1 th Effec ivision/Risk Assessment 

Branch 1 (HED/RAB I) itl(jf)<flhltNote: This Data Evaluation Record (DER) was originally prepared under contract b Versar, Inc. (6850 Versar Center, 

Springfield, VA 22 151; submitted 9/05114). The DER has been reviewed by 1 IED and revised to reneet current Office of 

Pesticide Programs (OPP) policies. 

EXECUTIVE SUMMARY 

The Interregional Research Project Number 4 (IR-4) has submitted field trial data for 

prohexadione calcium on watercress from three field tri als conducted in the United States during 

the 2009 growing seasons in the North American Free Trade Agreement (NAFT A) Growing 

Zones 2 (MD; 1 trial) and 3 (FL; 2 trials). The three trials reflected herein include two pairs of 

trials conducted in MD and FL that HED has determined to be replicate tri als and a third side-byside trial that was conducted at the same location in FL but reflected a different use pattern 

(chemigation vs. foliar broadcast application). 

Each trial consisted of one untreated plot and one treated plot (pond) with the exception of Trial 

FL24, which had two treated plots set up in different ponds. For purposes of this review, the 

second plot will be treated as a separate tri al herein. At each trial one treated plot received four 

foliar broadcast applications of a 27 .5% water-dispersible granule (WO) formulation of 

EPA MRJD #: 49339002 

Page I of8 
Prohexadione calcium [PC Code l I 2600]ffhe Interregional Research Project No. 4 (IR-4) [BAS 125 W) 

prohexadione calcium (Apogee® Plant Growth Regulator) at 0.135-0.143 lb ai/ Napplication, 

with two applications each made before the first and second cuttings for total rates of 0.272-

0.284 lb ai/ A for each cutting. After the first harvest, the watercress was cut and allowed to 

regrow before the second set of applications. At Trial FL24, a second treated plot received four 

foliar overhead chemigation applications at 0.140 lb ai/ Napplication as above for total rates of 

0.280 lb ai/ A for each cutting. The spray mixtures for the chemigation applications also included 

a tebuconazole end-use product as pai1 of another study. Data and information pertaining to 

tebuconazole were not addressed further in the study. Applications were made at retreatment 

intervals (R Tis) of 6-7 days between first and second and third and fourth applications; RTis 

were 15-24 days between the second and third applications. Applications were made in spray 

volumes of29.4-59.2 gal/A using ground equipment for foliar broadcast applications and in 

spray volumes of l 06.8-250.5 gal/ A for chemigation applications. A nonionic surfactant (NIS) 

was added to the spray mixture for all applications. Samples of watercress from each cutting 

were harvested at maturity at a 3-day preharvest interval (PHI). 

All samples were maintained frozen at the testing facility, during shipment to the laboratory, and 

were stored frozen until analysis. The maximum storage interval for samples between harvest 

and extraction for analysis was 794 days (26. l months). Samples were analyzed within l day of 

extraction. To support sample storage durations, a concurrent storage stability study was 

conducted with the field trial study. No 0-day data were provided. The data demonstrate that 

residues of prohexadione calcium declined in/on watercress during frozen storage for up to 792 

days (recovery of 66%). Reported residues were corrected for loss on storage. These data are 

acceptable to support the storage conditions and durations of the samples from the submitted 

field trials; however, storage stability studies should always include a 0-day sampling interval to 

establish the residue levels present at the time samples are placed into storage [see OCSPP 

860.1380( d)(6)(i)]. 

Samples were analyzed for residues of prohexadione calcium using a gas chromatography 

method with mass-spectrometry detection (GC/MS), BASF Method No. 0960 I with minor 

modifications. The limit of quantitation (LOQ; determined as the lowest level of method 

validation, LLMV) was 0.10 ppm for watercress. Acceptable method validation and concurrent 

recoveries were reported for watercress samples at fortification levels of O. l 0-5 .0 ppm, thus 

validating the method. The fortification levels were adequate to bracket expected residue levels. 

In watercress harvested at PHis of 3 days following the last of two broadcast foliar or 

chemigation applications of the 27.5% WG formulation of prohexadione calcium at a total rate 

of0.272-0.284 lb ai/A, individual sample (and per-trial average) residues of prohexadione 

calcium were 0.298-2.00 (0.32 1-1.72) ppm. Residues were generally lower in second-harvest 

samples than they were in first-harvest samples, and residues were lower following chemigation 

applications than they were following foliar applications: overall average residues were 0.347 

ppm following chemigation applications vs. 1.30 ppm following foliar applications. Residue 

decline was not evaluated. 

I. MATERIALS AND METHODS 

EPA MRJD #: 49339002 

Page 2 of8 
Prohexadione calcium [PC Code l 12600]ffhe Interregional Research Project No. 4 (IR-4) [BAS 125 W] 

A. MA TE RIALS 

Table B.7.6. 1.2- 1. Nomenclature fo r Prohexadionc Calcium. 

Common name Prohexadionc calcium 

IUPAC name Calcium 3-oxido-5-oxo-4-propionylcyclohex-3-enecarboxylate 

CAS no. 127277-53-6 

Company experimental name BAS 125 W 

Other synonyms (if applicable) NA 

- -

~ CHJ ,. Ca 

0 

0 

0 '- -

B. Study Design 

1. Test Procedure 

Three residue trials were conducted on watercress with a 27.5% WG formu lation of 

prohexadione calcium during the 2009 growing season (Table B.7.6. 1.2-2). Two pairs of trials 

were conducted at the same locations and reflected the same use pattern. HED has determined 

that these trials should be considered replicates as detailed in the table below. 

Independent Trial Dctermination1 

Trial Nos. Di fforcnccs Decision 

FL24-02 and FL25 Same location Replicate 

Variety: B& W #47 vs. B& \V # I 

Trials were conducted in separate ponds 

*No other differences in guidance criteri a. 

MD02 and M003 Same location and varietv Replicate 

Trials were conducted in separate ponds 

*No other differences in guidance criteria. 1 All assessments are based on the replicate trial guidance presented 111 drafi memo 568_Cntena for Independence of Trials 

04/23120 13 (EPA and PMRA). 

Table B.7.6. 1.2-2. Tria l Numbers a nd Geographica l Locations. 

Crop No. NAFT A Growing Zone Total Trials I 2 3 4 5 6 7 8 9 10 II 12 

Watercress Sub. I 2 3 

Req. 1 2 1 As per Table I of 860. 1500. Geographic distribution is not speci lied for crops requiring three or fewe r trials. 

Locations and detailed use patterns for the trials are provided in Table B.7.6.1.2-3. 

EPA MRID #: 49339002 

Page 3 of8 
Prohexadione calcium [PC Code I I 2600]ffhe Interregional Research Project No. 4 (IR-4) (BAS 125 W] 

Ta ble B. 7.6. 1.2-3. Study Use Pa ttern. 

Location: End-use Plot Method of Application/ Timing 

County/City. Product' of Application 

State; Year 

(Trial ID) 

Indian River 27.5% 02 I. foliar broadcast before I" 

County, FL; WG cutting; vegetative 

2009 2. Foliar broadcast before I" 

(FL24-02) cutting: vegetative 

3. Foliar broadcast before 2nd 

cutting: vegetative 

4. Foliar broadcast before 2nd 

cutting: vegetative 

(FL24-03) 27.5% 03 I. foliar overhead chemigation 

WG before I" cutting; vegetative 

2. Foliar overhead chemigation 

before 15' cutting: vegetative 

3. Fol iar overhead chemigation 

before 2nd cutting; vegetative 

4. foliar overhead chemigation 

before 2nd cutting; vegetative 

Indian River 27.5% NA I. foliar broadcast before I" 

County. FL: WG cutting; vegetative 

2009 (FL25) 2. Foliar broadcast before I" 

cutting: vegetative 

3. Foliar broadcast before 2nd 

cutting: vegetative 

4. Foliar broadcast before 2nd 

cutting; vegetative 

Clearspring. 27.5% NA I. Foliar broadcast before I" 

MD: 2009 WG cutting: pre-bloom 

(MD02) 2. Foliar broadcast before I" 

cutting; pre-bloom; first buds 

3. Foliar broadcast before 2nd 

cutting: pre-bloom 

4. Foliar broadcast before 2nd 

cutting; pre-bloom 

Clearspring. 27.5% NA I. Foliar broadcast before 151 

MD; 2009 WG cutting; pre-bloom 

(MD03) 2. Foliar broadcast before I" 

cutting: pre-bloom: first buds 

3. Foliar broadcast before 2nd 

cutting; pre-bloom 

4. Foliar broadcast before 2nd 

cutting; pre-bloom . 1 27.:>% WG formulation (Apogcclll Plant Growth Regulator) . 2 Total rate after each cutting. 3 NIS = nonionic surfactant. 

Volume Rate per Retreatment Total 

(gal/A) Application Interval Rate2 

(lb ai/ /\) (days) (lb ai/A) 

30.24 0.142 -- 0.282 

29.85 0. 140 7 

29.80 0. 140 24 0.278 

29.37 0.138 7 

214.12 0.140 -- 0.280 

123.94 0.140 7 

106.76 0. 140 24 0.280 

250.52 0.140 7 

30. 17 0. 141 -- 0.279 

29.36 0.138 7 

29.73 0. 139 24 0.278 

29.63 0. 139 7 

58.13 0. 135 -· 0.272 

59.19 0.137 7 

59.22 0.140 15 0.277 

57.93 0. 137 6 

46.22 0.141 -· 0.284 

47.02 0. 143 7 

41 .07 0. 139 15 0.279 

4 1.1 3 0. 140 6 

Surfactant/ 

Adjuvant

3 

NIS 

NIS 

NIS 

NIS 

NIS 

Watercress was grown and maintained according to typical agricultural practices. No unusual 

weather conditions were reported to have affected crop growth or development during the study. 

EPA MRID #: 49339002 

Page 4 of8 
Prohexadione calcium [PC Code I I 2600)rrhe Interregional Research Project No. 4 (IR-4) [BAS 125 W] 

Sample Handling and Preparation 

Duplicate control and treated samples of watercress were collected at maturity (3-day PHI) after 

the last application. All samples were placed into frozen storage within - 6 hours of collection 

and were stored frozen ( <0-10 °F) at the field sites for 5-26 days before shipment via ACOS 

freezer truck to the University of Florida Food and Environmental Toxicology Laboratory 

(Gainesville, FL). At the analytical laboratory, samples were homogenized in the presence of 

dry ice and were stored at -37 to 7 °C until extraction for analysis. 

2. Description of Analytical Procedures 

Samples were analyzed for prohexadione calcium using a previously validated GC/MS, BASF 

Method No. 09601 with minor modifications (Memo, 3/10/01, G. Kramer, 0273510, MRID 

48 106701 ). A complete description of the method was included in the submission. 

Briefly, samples were extracted twice with acetonitrile (ACN): 1.5 M sulfuric acid (9: 1, v:v), then 

homogenized with 0.05 M sodium acetate and filtered. The combined extract was applied to an 

ENV+ solid-phase extraction (SPE) cartridge, and residues were eluted with methanol. Sulfuric 

acid was added to the eluate, and the mixture was refluxed to convert prohexadione carboxylic 

acid to methyl prohexadione carboxylate. The resulting extract was applied to an ENV+ SPE 

cartridge. Residues were eluted with 0.01% oxalic acid in acetone (w/v), and the eluate was 

reduced under nitrogen for analysis by GC/MS. The method determines residues of 

prohexadione calcium as the methyl ester, methyl prohexadione carboxylate. Residues of methyl 

prohexadione carboxylate were converted to prohexadione acid equivalents by the petitioner 

using a molecular weight conversion factor of 0. 93 8, and these residues were reported 

incorrectly as prohexadione calcium in the study. The reported residues of prohexadione acid 

were converted to prohexadione calcium equivalents by the study reviewer using a molecular 

weight conversion factor of 1.179. The LOQ (determined as the LLMV) was 0.10 ppm. 

We note that the petitioner also presented calculated values for the limit of detection (LOO) and 

LOQ based on recoveries obtained at the O. l 0-ppm fortification level. The LOD was calculated 

by multiplying the standard deviation of recovery measurements at the LLMV by the one-tailed 

t-statistic (confidence level not reported) for 6 replicates, and the LOQ was defined as 3x the 

LOO. The calculated LOD and LOQ were 0.015 ppm and 0.046 ppm, respectively. 

EPA MRJD #: 49339002 

Page 5 of8 
Prohexadione calcium [PC Code I I 2600]ffhe Interregional Research Project No. 4 (I R-4) [BAS 125 W] 

II. RESULTS AND DISCUSSION 

Method performance was evaluated during method validation and by use of concurrent recovery 

samples. For method validation, nine samples of untreated watercress were fortified with 

prohexadione calcium at 0.10, 0.50, and 5.0 ppm; individual recoveri es were 70-78% with a 

standard deviation of 2.8%. For concurrent recovery, nine samples of untreated watercress were 

fortified at 0.10, 0.50 and 5.0 ppm; individual recoveries were 69-87% with a standard deviation 

of 5 .6%. Recoveries were generally within the acceptable range of 70%-120%; therefore, the 

method was considered valid for the analysis of residues of prohexadione calcium in watercress 

matrices. The fortification levels bracketed the measured residues. Concurrent recoveries were 

not corrected for apparent residues in controls. 

The detector response was linear (coefficient of determination, r2 2:0.979 1) within the range of 

0.0204-0.143 ng/mL. Representative chromatograms of control samples, fortified samples and 

treated samples were provided. The control chromatograms generally had no peaks of interest 

above the chromatographic background. The fortified sample chromatograms contained only the 

analyte of interest, and peaks were symmetrical and well defined. Apparent residues in controls 

were below the LOQ ( <0.10 ppm). The reported residue values were not corrected for apparent 

residues in controls. The reported residues of prohexadione acid were converted to prohexadione 

calcium equivalents by the study reviewer using a molecular weight conversion factor of 1.179. 

Table B.7.6.1.1-4. S ummary of Method Validation a nd Concurrent Recoveries of Prohexadione (free acid) 

from Watercress. 

Matrix Fortification Level Recoveries Mean ± Std. Dev. 

(oom) (%) (%) 

Method Validation Recoveries 

Watercress 0. 1 73, 75, 74 74 ± 0.8 

0.5 7 1, 78, 78 76 ± 3 

5.0 72. 75. 70 72 ± 2 

Overall Ranee: 70 to 78 74 ± 3 

Concurrent ll.ccoveries 

\.\latercress 0.1 76, 78, 85 80 ± 4 

0.5 69, 84, 84.80 79 ± 6 

5.0 79.87 83 

Overall Ran2e: 69 to 88 80±5 

The field residue samples were stored frozen a maximum of 794 days (26.1 months) from 

harvest to extraction for analysis (Table B. 7.6. l.2-5a). Freezer storage stability data were 

generated concurrently with the watercress field trials; the results are presented in Table 

B.7.6. l .2-5b. No 0-day data were provided. The data demonstrate that residues of prohexadione 

calcium declined in/on watercress for up to 792 days (26. l months) of frozen storage. Reported 

residues were corrected for loss on storage. These data are acceptable to suppo11 the storage 

conditions and durations of the samples from the submitted field trials; however, storage stability 

studies should always include a 0-day sampling interval to establish the residue levels present at 

the time samples are placed into storage [see OCSPP 860. l 380(d)(6)(i)). 

EPA MRID #: 49339002 

Page 6 of8 
Prohexadione calcium [PC Code 112600)ffhe Interregional Research Project No. 4 (IR-4) [BAS 125 W] 

Table B.7.6.1.2-Sa. Summary of Storage Conditions. 

Matrix Storage Temperature (

0 C) Actual Storage Interval of Demonstrated Storage Stabi lity 

(RJ\C or Extract) Duration' (days/months) 

(days/months) 

Watercress 0- 10 °F at the field sites; 700-794 days Residues declined by - 34% following storage 

-37 to 7 °C at the laboratory (23.0-26.1 months) for 792 days.

2 

1 Interval from harvest to extraction. Samples were analyzed within 0-1 days of extraction. 2 Based on concurrent storage stability study. Sec Table 7.6. I .2-5b. 

Table B. 7 .6.1.2-Sb. Stability of Prohexadione Calcium Residues in Watercress. 

Commodity Spike Storage Fresh Fortification Stored Sample Recoveries Mean Recovery Corrected% 

Level Interval Recoveries(%) (%) (%) Recovery• 

(ppm) (days) 

Watercress 0.5 792 80 52, 48, 58 53 66 

1 Corrected for recovery in freshly fortified samples. 

The results from the submitted field trials are presented in Tables B.7.6.1.2-6 and B.7.6.1.2-7. In 

watercress harvested at PHis of 3 days following the last of two broadcast foliar or chemigation 

applications of the 27.5% WG formulation of prohexadione calcium at a total rate of 0.272-0.284 

lb ai/ A, individual sample (and per-trial average) residues of prohexadione calcium were 0.298-

2.00 (0.321-1. 72) ppm. Residues were generally lower in second-harvest samples than they were 

in first-harvest samples, and residues were lower following chemigation applications than they 

were fo llowing foliar applications: overall average residues were 0.347 ppm following 

chemigation applications vs. 1.30 ppm following foliar applications. Residue decline was not 

evaluated. 

Table B.7.6.1.2-6. Residue Data from Watercress Field Trials with Prohexadione Ca lcium. 1 

Location: Zone Crop/ Matrix Rate PHI Residues2 (ppm prohexadione 

County/City, State; Variety (lb ai/A) (days) calcium) [/\ veragel 

Year (Trial ID) As found Corrected for 

decline on storage 

Indian River County, 3 Watercress/ Leaves and stems; 0.279-0.282 3 1.32, 1.26, 2.00, l.9I, 

FL; 2009 (FL24-02) B & W #47 1 SI cutting 0.968, 0.993 1.47, 1.50 

a nd Indian River and [ 1.1 4] [I. 72] 

County, FL: 2009 B& W# l Leaves and stems; 0.278 3 0. 705, 0.59 1, 1.07, 0.895, (FL25) 2nd cutting 0.626, 0.696 0.949, 1.05 

[0.654) [0.99 I] 

Indian River County. 3 Watercress/ Leaves and stems: 0.280 3 0.220. 0.203 0.334, 0.307 

FL; 2009 (FL24-03) B& W#l I SI cutting [Chcmigation] [0.2121 [0.321] 

Leaves and stems; 0.280 3 0. 197,0.296 0.298, 0.448 

2"d cutting [Chemigation] [0.246) [0.373] 

Clearspring, MD; 2 Watercress/ Leaves and stems; 0.272-0.284 3 1.06, 1.00, 1.61, 1.52, 

2009 (MD02) and B & W #47 ISi cutting 0.81 I, 0.856 1.23, 1.30 

Clearspring, MD: [0.933] [ 1.41] 

2009 (MD03) Leaves and stems; 0.277-0.279 3 0.686. 0.710, 1.04, 1.08 

2nd cutting 0.723, 0.725 I. IO, 1.1 0 

[0.71 I] [ 1.08] 

1 The 27.5% WO formulation {Apogee® Plant Growth Regulator) was used. 2 Residues of prohcxad ionc calcium were determined as methyl prohcxadionc carboxylatc by the method. Residues were 

converted to prohexad ione acid equivalents by the petitioner using a molecular weight conversion factor of0.938, and these 

residues were reported incorrectly as prohcxadione calcium in the MRID. The reported residues of prohcxadione acid were 

converted to prohexadione calcium equivalents by the study reviewer using a molecular weight conversion factor of I .179 and 

arc presented above "As found." These residues were then corrected for decline on storage (- 34%) by the study reviewer. 

EPA MR10 #: 49339002 

Page 7 of8 
Prohexadione calcium [PC Code I 12600]ffhe Interregional Research Project No. 4 (IR-4) [BAS 125 W) 

Table B.7.6.t.2-7. Summa ry of Residues from Wa tercress Field Trials with Prohexadione Calcium. 

Crop Matrix Total Application Piii n' Residues (ppm Prohexadionc calcium) 

Rate (lb ai/A) (days) Min.

2 Max. 2 LAFT1 HAFT3 Mcdian3 Mean3 

As Found 

Watercress. 1st cutting 0.272-0.284 3 3 0.203 1.32 0.2 12 1.1 4 0.933 0.760 

Watercress. 2nc1 cutting 0.277-0.280 3 3 0. 197 0.725 0.246 0.711 0.654 0.537 

Watercress combined 0.272-0.284 3 3 0. 197 1.32 0.212 1.14 0.683 0.649 

Corrected for decline on storagt: 

Watercress. I st cutting 0.272-0.284 3 3 0.307 2.00 0.321 1.72 1.4 1 1. 15 

Watercress. 2"d cutting 0.277-0.280 3 3 0.298 1. 10 0.373 1.08 0.991 0.814 

Watercress combined 0.272-0.284 3 3 0.298 2.00 0.32 1 1.72 1.03 0.983 

1 n = number of field trials. 2 Values based on total number of samples. 3 Values based on per-trial averages. LAFT = lowest average field trial, I IAFT = highest average fi eld trial, SD = standard 

deviation. 

Ill. CONCLUSIONS 

soi 

0.486 

0.253 

0.367 

0.736 

0.384 

0.557 

The watercress field trials are considered scientifically acceptable. In watercress harvested at 

PH Is of 3 days following the last of two broadcast fo liar or chemigation applications of the 

27.5% WG formulation of prohexadione calcium at a total rate of 0.272-0.284 lb ai/ A, individual 

sample (and per-trial average) residues ofprohexadione calcium were 0.298-2.00 (0.32 1-1.72) 

ppm. Residues were generall y lower in second-harvest samples than they were in first-harvest 

samples, and residues were lower following chemigation applications than they were following 

foliar applications: overall average residues were 0.347 ppm following chemigation applications 

vs. 1.30 ppm following fo liar applications. Residue decline was not evaluated. 

An acceptable method was used for residue quantitation, and adequate storage stability data were 

submitted to support sample storage durations and conditions. 

REFERENCES 

None 

EPA MRJO #: 49339002 

Page 8 of8 
Prohexadione calcium [PCB)/ BASF Canada Inc. [BAZ] 

OS-May-20 l S 

B.7.6 Residues Resulting from Supervised Trials 

(Annex IIA 6.3; Annex IIIA 8.3) 

B.7.6.l Residues in Target Crops 

B. 7.6.1.l Strawberries 

Document ID: PMRA No. 237S772 

MRID No. 49339001 

Report: 

Guidelines: 

Liu, S. (2013). "Prohexadione Calcium: Magnitude of the Residue on 

Strawberry". Study Number: AAFCI0-016R. Unpublished study prepared 

by Agriculture and Agri-Food Canada, Ottawa, ON, Canada. 27S pages. 

EPA OCSPP Harmonized Test Guideline 860.1 SOO Crop Field Trials 

(August 1996) 

PMRA Regulatory Directive DIR98-02 - Residue Chemistry Guidelines, 

Section 9 - Crop Field Tria ls 

PMRA Regulatory Directive DIR2010-0S - Revisions to the Residue 

Chemistry Crop Field Trial Requirements 

OECD Guideline S09 Crop Field Trial (September 2009) 

GLP Compliance: No deviations from regulatory requirements were reported which would 

Acceptability: 

Evaluator: 

have an impact on the validity of the study. 

The study is considered scientifically acceptable. 

Pamela Chu, Evaluation Officer, MUAS, HED 

William D. Wassell, Chemis f ealth ffe ivision/Risk Assessment 

Branch I (HED/RAB 1) /f/Vjf/) t.JVt 

EXECUTIVE SUMMARY 

Nine field trials for prohexadione calcium on strawberries were conducted in Canada and the 

United States encompassing North American Free Trade Agreement (NAFT A) Growing Regions 

I A (l in NS), 2 (l in NJ), 3 ( 1 in FL), S (1 in ON), SA (1 in MI), SB (1 in QC), 10 (2 in CA), and 

12 (1 BC) during the 2010 and 2011 growing seasons. • 

At each trial location, prohexadione calcium, formulated as a wettable granule, was applied to 

strawberries as three foliar applications. The rate ranged from 36.0 g ai/ha (0.0321 lbs ai/A) to 

40.8 g ai/ha (0.0364 lbs ai/A), the re-treatment intervals (RTis) were 8-lS days, and the total 

application rate was 110 g ai/ha (0.0990 lbs ai/ A). For each application, a non-ionic surfactant 

was added in the spray mixture at a 0.05% (v/v) rate and ammonium sulfate was added at a 1: 1 

ratio. Strawberries were harvested at preharvest intervals (PHis) of 16-25 days. In one trial 

(# 121 ), samples were collected at different time intervals (PH Is of 13, 19, 26, 31 days) to assess 

residue decline behaviour. 

All samples were maintained frozen at the testing facility, during shipping to the laboratory, and 

were stored frozen until analysis. The maximum storage interval for samples between harvest 

Pa e I of 8 

EPA MRID No.49339001 
Prohexadione calcium [PCB]/ BASF Canada Inc. [BAZ] 

and analysis was 390 days (- 13 months). Residues of prohexadione have been shown to be 

stable in strawberries for up to 422 days (- 14 months) under frozen conditions. Adequate 

storage stability data are therefore available to support the storage conditions and intervals for 

samples in the current trials. 

Samples in the current study were analyzed for residues of prohexadione calcium using a highperformance liquid chromatography method with tandem mass spectrometry detection 

(LC/MS/MS) working method based on Method 564/0 entitled, "Validation of the analytical 

method 564/0: Method for the determination of prohexadione-Ca in plant and animal matrices," 

(PMRA# 1525282, MRID No. 4810670 l) to determine residues of prohexadione calcium. This 

method has been previously reviewed and deemed acceptable for data gathering and enforcement 

(S2007-8864/-8867; PMRA# 1628696; Memo, 11/22/99, G. Kramer, 0252547). Acceptable 

method validation and concurrent recoveries were reported for residues of prohexadione calc ium 

in/on strawberry fruit samples at fortification levels of 0.01 , 0.1, and l.O ppm thus validating the 

method. The limit of quantitation (LOQ) was 0.01 ppm for prohexadione in strawberry fruits. 

Individual sample (and per-trial average) residues in strawberries ranged from 0.03 ppm to 0.16 

ppm (0.03 ppm to 0.15 ppm). Residue decline data show that residues of prohexadione calcium 

decrease in strawberries with increasing PHis. 

I. MA TERI A LS AND METHODS 

A. MATERIALS 

Table B.7.6.1.1-1. Nomenclature fo r Prohexadione calcium. 

Common name Prohcxadionc calcium 

IUPAC Calcium 3-oxido-5-oxo-4-propionylcyclohex-3-cnccarboxylatc 

CAS no. 127277-53-6 

Company experimental name BAS 125 W 

Other synonyms (if applicable) NA 

~ -

#'"• ,. Ca 0 

0 

0 ~ 

-

B. Study Design 

1. Test Procedure 

A total of nine residue trials on strawberries were conducted with a wettable granule formulation 

in Canada and the United States during the 2010-2011 growing season (Table 8. 7 .6. l.1-2). 

Paoc 2 of8 

EPA MRID No.49339001 
Prohexadio ne calcium [PC B)/ BASF Canada Inc. [BAZ] 

Table B.7.6. 1.1 -2. Trial Numbe rs a nd G eographical Locatio ns. 

Crop No. Trials NA IT A Growing Zone Total 

I IA 2 3 4 s SA SB 6 7 8 9 10 11 12 

Straw- Submitted I I I 2 I 2 I 9 

berry Req. U.S.

1 Ill 110 Ill Ill 312 Il l 816 

Req. Can. 2 1 I I I I 5 

1 As per Table 5 of 860. 1500 for strawberry; the second number re flects a 25% reduction in the number of fie ld trials allowed for 

the crop as a repn.:senlative commodity in support of a crop group/subgroup tolerance or when application results in no 

quantifiab le residues. 2 J\s per Table 1.2 of PMRA Regulatory Directive DIR20 I 0-05. 

Locations and detailed use patterns for the trials are provided in Table B.7.6.1.1-3 . 

Table B.7.6. 1.1-3. Stud·v Use Pattern. 

Location: City. Volume Rate per Rctrealmenl Total Rate State/Province: End-use Product/ Method of Application/ 

IUha l Application Interval [g ai/ha] Surfactant/ 

Year Formulation (% ai) Timing of Application (gal/A) [g ai/ha] (days) (lbs ai/A) Adjuvant 

(Trial ID) (lbs ai/A) 

Kentvil le. NS/20 I 0 Apogee/ I. Foliar/ Green berries. 306 37.9 NIA 11 1 Activate Plus 

Trial ID # 11 9 Wettable Granules runners started (33. 7) (0.0338) (0.099) 0.05% (v/v). 

(27.4%) 2. Foliar/ Fruiting 293 36.3 14 Ammonium 

(32.2) (0.0324) sulfate ( I: I) 

3. Foliar/ Fruiting 297 36.7 13 

(32.7) (0.0327) 

I I arrow. ON/20 I 0 Apogee/ I. Foliar/ Some 330 -1 0.8 NIA 11 6 Agral 90 0.05% 

Trial ID # 120 Wettable Granules flowering (36.3) (0.0364) (0. 103) (v/v). 

(27.4%) 2. Foliar/ Flowering 313 38.7 13 Ammonium 

(34.4) (0.0346) sulfate ( I: I) 

3. Foliar/ Fruiting 298 36.9 13 

(32.8) (0.0329) 

Frelighsburg. Apogee/ I. Foliar/ Started 3 10 38.4 NIA 114 Agral 90 0.05% 

QC/2010 Wettable Granules fl owering (34. 1) (0.0343) (0. 102) (v/v), 

Trial ID # 12 1 (27.4%) 2. Foliar/ Starting to 307 38. 1 13 Ammonium 

fruit and fl owering (33.8) (0.0340) sulfate ( I: I) 

3. Foliar/ Fruiting and 303 37.5 15 

flowering (33.3) (0.033 5) 

Langley. BC/20 I 0 Apogee/ I. Foliar/ BBCH 15 294 36.4 NIA 111 Agral 90 0.05% 

Trial ID fl 122 Wettable Granules (Vegetative stage) (32.3) (0.0325) (0.099) (v/v), 

(27.4%) 2. Foliar/ Vegetative 30 1 37.3 13 Ammonium 

(33. 1) (0.0333) sul fate(l :I) 

3. Foliar/ Flowering 299 37.2 14 

(32.9) (0.0332) 

Cream Ridge. Apogee/ I. Foliar/ Bloom 307 37.9 NIA 112 Attach, 0.05% 

NJ/20 10 Wettable Granules (33.8) (0.0338) (0.0999) (v/v), 

Trial ID # 170 (27.4%) 2. Foliar/ Small green 297 36.7 9 Ammonium 

frui t (32.7) (0.0327) sulfate ( I: I) 

3. Foliar/ Fruiting 300 37. 1 8 

(33.0) (0.033 1) 

Parlier. CN2010 Apogee/ I. Foliar broadcast/ 307 38. 1 NIA 11 4 Induce. 0.05% 

Trial ID # 17 1 Wettable Granules Vegetative/blooming (33.8) (0.034) (0. 102) (v/v). 

(27.4%) 2. Foliar broadcast/ 306 37.9 14 Ammonium 

Fruiting/blooming (33.7) (0.0338) sulfate ( I: I) 

3. Foliar broadcast/ 303 37.6 12 

Fruitin!t (33.3) (0.0336) 

lloll, M 1/20 I 0- Apogee/ I. Foliar/ Vegetative 291 36.0 NIA 111 Activator 90. 

20 11 Wellable Granules (32.0) (0.032 1) (0.099) 0.05% (v/ v). 

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Table 8.7.6.1.1-3. Study Use Pattern. 

Location: City, Volume Rate per Retrcatmcnt Total Rate State/Province: End-use Product/ Method of Application/ 

IUhaJ Application Interval [g ai/ha] Surfac1ant/ 

Year Formulation (% ai) Timing of Application [g ai/hal Adjuvant 

(Trial ID) (gal/A) (lbs ai/A) (days) (lbs ai/A) 

Trial ID # 233 (27.4%) 2. Foliar/ Early 300 37.1 13 Ammonium 

nowering (33.0) (0.0331) sulfate ( l: I) 

3. Foliar/ 309 38.2 14 

Flowering/fruiting (34.0) (0.0341 ) 

Balm. Fl/2010- Apogee/ I. Foliar broadcast/ 304 37.6 NIA 113 De-Fae 820. 

20 11 Wettable Granules Bloom to fruiting (33.4) (0.0336) (0.101 ) 0.05% (v/v). 

Trial ID # 234 (27.4%) 2. Foliar broadcast/ 8 10 307 38.0 14 Ammonium 

11 cm (33.8) (0.0339) sulfate ( I: I) 

3. Foliar broadcast/ 305 37.8 15 

Bloom to fruiting (33 .6) (0.0338) 

Salinas. CA/2010 Apogee/ I. Foliar/ Flowers and 295 36.5 NIA 111 R-11. 0.05% 

Trial ID #235 Wettable Grnnulcs fruiting (32.5) (0.0326) (0.099) (v/v). 

(27.4%) 2. Foliar/ Flowers and 308 37.2 14 Ammonium 

fruiting (33.9) (0.0332) sulfate ( I: I) 

3. Foliar/ Flowers and 303 37.2 13 

fruiting (33.3) (0.0332) 

Strawberries were grown and maintained according to typical agricultural practices. Irrigation 

was used at all trial sites except trial IDs 120 and 233. No unusual weather conditions were 

reported during the study. Temperatures were within 4.4°C (7.9°F) of normal and precipitation 

was within 114.1 mm (4.49 in) of normal. Trial IDs# 119, 120, and 233 received more rainfall 

than normal while Trial IDs# 122, 170, and 234 received significantly less precipitation. 

Sample Handling and Preparation 

Two untreated and two treated samples of mature strawberries were hand-picked 20-23 days 

after final application. However, only one sample was collected from each plot in Trial ID # 170 

due to early ripening and in Trial ID # 120, 122, and 170, sampling dates were modified ( 16, 25, 

and 17 days, respectively) to ensure collection of representative mature strawberries. Untreated 

samples were collected first or by a different person to avoid contamination. Ends and edges of 

plots were avoided. Each sample surpassed the minimum target weight of 1 kg except Trial IDs 

# 121 and 170 where sample sizes were reduced due to wildlife interference and/or early fruit 

ripening. Samples were placed in bags then placed in coolers where they were shipped to site 

facility freezers within 4 hours and 33 minutes of harvest. All samples were stored frozen in the 

freezers (S-l 8°C/ -0.4 F) until shipment to the analytical laboratory (ADPEN Laboratories Inc., 

FL). All samples arri ved frozen and in good condition at the analytical laboratory and stored 

frozen (-29 to 3°C/ -20.2 to 37.4°F) until maceration and extraction. The maximum temperature 

(3°C/ 37.4°F) was due to a temporary freezer malfunction, however the study report indicates 

that the samples remained frozen during this period. Strawberry samples were homogenized with 

a Hobart food processor with dry ice and kept frozen until analysis. 

2. Description of Analytical Procedures 

Samples of strawberries were analyzed for residues of prohexadione calcium, detem1ined as 

prohexadione (free acid), using an LC/MS/MS workjng method based on the reference method 

564/0: "Validation of the analytical method 564/0: Method for the determination of 

prohexadione-Ca in plant and animal matrices," (PMRA# 1525282, MRlD No. 4810670 l ). This 

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method has been previously reviewed and deemed acceptable for data gathering and enforcement 

(S2007-8864/-8867; PMRA# 1628696; Memo, 3/ 10/01 , G. Kramer, D273510). Minor 

modifications were made to the method: additional standards were added to the calibration curve 

and extracts were centrifuged longer at a slightly lower rpm. 

Briefly, samples were extracted with acetonitrile: 2M H2S04 solution. Extracts were cleaned up 

using solid-phase extraction (SPE) column eluted with acetonitrile: methanol: formic acid. 

MS/MS detection in positive ionization mode monitored ion transitions from mlz ~ 157 for 

prohexadione. A molecular weight conversion factor ( l .179) was used to express the free acid as 

prohexadione calcium equivalent. The LOQ was 0.0 l ppm for prohexadione and the limit of 

detection (LOD) estimated to be 0.003 ppm. 

II. RESULTS AND DISCUSSION 

Method performance was evaluated during method validation by fortifying strawberry fruit with 

prohexadione at 0.0 I, 0. 1, and 1.0 ppm. Nine samples of strawberry fruit were fortified with 

prohexadione (three samples were fortified at each spiking level). Method validation recoveries 

at spiking levels of 0.0 I ppm, 0. 1 ppm, and 1.0 ppm ranged from 88% to 107% (S.D. ± 10%), 

87% to 89% (S.D. ± 1 %), and 75-79% (S.D. ±2%), respectively. The method was also validated 

concurrently by spiking control strawberry fruit samples with 0.0 I and 1.0 ppm of prohexadione. 

Recoveries at the 0.01 ppm and 1.0 ppm spiking levels ranged from 71-108% (n=9, S.D. ± 12%) 

and 76-110% (n=9, S.D. ± 10%), respectively. All recoveries were within the acceptable range of 

70% to 120%. Therefore, the method was considered valid for the analysis of prohexadione 

residues in strawberry matrices (Table B.7.6.1. 1-4). The fortification levels did bracket the 

measured residues. 

The detector response was linear (correlation coefficient, r 2: 0.9923) within the range of 0.0625-

25 ng/mL. Representative chromatograms of control samples, fortified samples and treated 

samples were provided. The control chromatograms generally had no peaks of interest above the 

chromatographic background. The fort ified sample chromatograms contained only the analyte of 

interest, and peaks were symmetrical and well defined. The reported residue values in fortified 

samples were corrected for apparent residues in controls. 

Table B.7.6. 1. l-4. Summary o f Method Validation and Concurrent Recoveries of Prohexadione (free acid) 

fro m Straw be rry Fruit. 

Matrix Fortification Level Recoveries Mean :!: Std. Dev. 

(oom) (%) (%) 

Method Validation Recoveries 

Strawberry fruit 0.01 88. 107. 92 96±10 

0. 1 88. 89. 87 88± 1 

1.0 76. 79. 75 77±2 

Concurrent Recoveries 

Strawberry fruit 0.01 I 00. I 08. 96. 85. 7 1. 98, 94. I 07, I 08 96±12 

1.0 85. 86. 83, 76. 78. 11 0. 90. 93. 86 87± 10 

The field residue samples were stored frozen a maximum of 390 days (- 13 months) from harvest 

to extraction (Table B.7.6. 1.1-5). Samples were analyzed within I day of extraction. 

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Freezer storage stability data were generated concurrently with the strawberry field trials. One 

untreated sample, three fortified storage samples, and three freshly fortified samples were 

analyzed at each storage interval. The concurrent freezer storage stability data indicate that 

residues of prohexadione were stable when stored frozen at ca. -l 8°C (~ 0.4 F) in strawberries 

for up to 422 days. There are no concerns with the stability of residues of prohexadione in/on 

treated strawberry samples from this study. 

Table B.7.6.2. 1-3. Stability of Pro hexadione Residues in Strawberries During Stora l!e at ca. °C. 

Storage Fortification Recovered Mean Mean Mean 

Commodity Duration Level Residues Recovery 

Concurrent Corrected 

(days/months Recovery Recovery' 

) (ppm) (ppm) (%) (%) (%) 

0.0795 

0 0.0822 82.5 93 89 

0.0858 

0.0966 

30 0.0922 92.6 100.6 93 

0.0890 

0.0869 

120 0.0277* 83.7 76.9 109 

0.0805 

0.0880 

Strawberry fruit 210 0.100 0.0929 91.2 97.5 94 

0.0928 

0.0903 

300 0.0853 86.9 98.7 88 

0.0852 

0.0826 

390 0.0753 76.6 97.0 79 

0.07 18 

0.0875 

422 0.0797 84.3 88.9 95 

0.0858 1 Corrected for concurrent recovery if below 100%. 

• The study report indicates that this value was determined to be an outlier by the Grubbs and Dixon test and was excluded in the 

calculation of the mean recovery. No explanation was provided for this very low recovery. 

Table 8.7.6.1.1-5. Summa r y of Storage Conditions. 

Matrix Storage Temperature Actual Storage Duration Interval of Demonstrated Storage Stability roq (RAC or Extract) (Or) (days) (days) 

A freezer storage stability study was conducted 

concurrently with the analytical portion of the 

Strawberry fru it -29 to 3 390* residue trial study. The data (sec Table 

(-20.2 to 37.4) B.7.6.2.1-3) indicate that prohcxadione residues 

are stable when stored frozen for up to .t22 

days. 

•From harvest to extraction. Samples were analyzed for residues within I day of extraction. 

The results from these trials showed that when harvested 16-25 days after the last of three 

applications at a seasonal rate of 111-1 16 g ai/ha (0.0990-0. 104 lbs ai/ A), residues of 

prohexadione calcium in strawberries ranged from 0.03 ppm to 0.16 ppm (Tables B.7.6.1.1 -6 and 

8.7.6.1.1 -7). 

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Jn the residue decline trials, mean residue level decreased from 0. IO ppm to 0.04 ppm in 

strawberry fruit between PHis of 13 and 31 days. 

T a ble B.7.6.1.1-6. Residue Da ta from Strawberry F ield Trials w ith Prohexadione Calcium. 

Location: City, Rate Total 

State/Province: Region Crop/ Matrix End-Use 

rg ai/ha] 

Pill Prohexadione calcium' (per-trial Year Variety Product (days) (ppm) 

(Trial ID) (lbs ai/A) average) 

Kentvillc. Strawberry/ 

0.04 

NS/2010 IA Seascape Fruit Apogee 111 2 1 0.04 

Trial ID fl 11 9 (Day- WG (0.0990) 

neutral) O.QJ 

Strawberry/ 

0.09 I I arrow, ON/20 I 0 5 Honeoye Fruit Apogee 116 16 0.09 Trial ID fl 120 (Jun1:- WG (0. 104) 0.09 bearing) 

13 0.09 0. 10 0. 10 

19 0.08 0.08 0.08 

Frelighsburg. Strawberry/ 

2 1 0. 10 0. 10 

QC/2010 SB Seascape Fruit Apogee 114 0. 10 

TrialID # 121 (Day- WG (0. I 02) 0.08 

neutral) 26 0.o7 0.08 

0.04 

31 0.04 0.04 

Strawberry/ O.oJ Langley. BC/20 I 0 12 Albion Fruit Apogee 111 25 0.04 Trial ID # 122 (Day- \VG (0.0990) 

neutral) 0.04 

Cream Ridge. Strawberry/ 

NJ/2010 2 Earliglow Fruit Apogee 112 17 0.06 0.06 

Trial ID # 170 (June- WG (0.0999) 

bearing) 

Strawberry/ 0.05 

Parlier. CN20 I 0 10 Albion Fruit Apogee 114 2 1 0.05 Trial ID # 17 1 (Day- WG (0.102) 

neutral) 0.05 

llolt, Ml/20 10- Strawberry/ 0. 16 

20 11 5 Jewel Fruit Apogee 111 20 0. 15 

Trial ID # 233 (June- WG (0.0990) 0. 13 bearing) 

Balm, FL/20 10- Strawberry/ 0.03 

20 11 3 Treasure Fruit Apogee 113 2 1 0.03 

Trial ID # 234 (June- WG (0. 101) 0.03 bearing) 

Salinas, CN2010 Strawberry/ 0.06 Trial ID 11235 Albion Apogee 111 10 (Day- Fruit WG (0.0990) 23 0.07 

neutral) 0.08 

'Expressed as prohexadione calcium equivalents 

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Prohexadione calcium [PCB]/ BASF Canada Inc. [BAZ] 

Table B.7.6.1.1-7. Summary of Residues from Strawberry Field Trials with Prohexad ione Calcium. 

Total Residues (ppm) 

Crop Application PHI 

Matrix Analyte Rate (days) n Min.

1 Max. 1 LAFT2 HAFT2 Mcdian2 Mean2 so2 

[g ai/ha] 

(lbs ai/A) 

Strawbcrr Prohexadionc 111 -116 

y fruit calcium (0.0990- 16-25 9 0.03 0. 16 0.03 0. 15 0.06 0.07 0.038 

0.1 04) 

1 Values based on total number of samples. 2 Values based on per-trial averages. LAFT = lowest average field trial. HAFT = highest average field trial, SD = standard 

dcviation. For computation of the LAFT. HAFT. median, mean. and standard deviation. values< LOQ are assumed to be at the 

LOQ (0.0 I ppm). 

n = number of licld trials. 

III. CONCLUSIONS 

The strawberry field trials are considered scientifically acceptable. The results of the study 

showed that following a total application of 111-116 g ai/ha (0.0990-0. l 04 lbs ai/ A) in 

strawberry samples collected at PI-Ils of 16-25 days, residues of prohexadione calcium ranged 

from 0.03 ppm to 0. 16 ppm. A decline study indicates that the level ofprohexadione calcium 

residues in strawberries decreases with time. Adequate storage stability data has been provided 

to support sample storage durations and conditions. 

REFERENCES 

PMRA# 1525282. MRJD No. 48 l 06701. Lclunann, A. and Mackenroth, C. (2005). "Validation 

of the analytical method 564/0: Method for the determination of Prohexadione-Ca in plant and 

animal matrices". Study code: 84609. BASF Doc 10 2005/100758 1. Unpublished study 

prepared by BASF Aktiengesellschaft, Limburgerhof, Germany. 63 pages. 

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