1 

OFFICE OF CHEMICAL SAFETY 

AND POLLUTION PREVENTION 

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

WASHINGTON, D.C. 20460 

August 18, 2015 

PC Code: 128819 

 DP Barcode: 428390 

MEMORANDUM 

SUBJECT: Forchlorfenuron: Response to Comments on the Preliminary Work Plan for 

Registration Review: Initial Docket Case Number 7057 

FROM: Christina Wendel, Biologist 

Environmental Risk Branch 2 

Environmental Fate and Effects Division (7507P) 

THROUGH: Elyssa Arnold, Risk Assessment Process Leader 

Brian Anderson, Branch Chief 

 Environmental Risk Branch 2 

Environmental Fate and Effects Division (7507P) 

TO: Wilhelmena Livingston, Chemical Review Manager 

 Cathryn Britton, Team Leader 

 Kevin Costello, Branch Chief 

 Risk Management and Implementation Branch 4 

Pesticide Re-evaluation Division (7508P) 

 

The Environmental Fate and Effects Division (EFED) has completed its response to public 

comments on the Preliminary Work Plan (PWP) for the Registration Review of Forchlorfenuron 

(Docket ID No.: EPA-HQ-OPP-2014-0641). Comments were received from KIM-C1, LLC 

(registrant for forchlorfenuron products), and the Center for Biological Diversity (CBD). The 

comments from CBD will be addressed by the Pesticide Re-evaluation Division (PRD). The 

comments received by KIM-C1, LLC that were relevant to EFED are summarized below, 

followed by EFED’s responses.

KIM-C1, LLC 

Comment 1: “Under Table 1 (“Anticipated Data Needs for the Forchlorfenuron Registration 

Review”), page 4, “Terrestrial plant toxicity, vegetative vigor” is listed. KIM-C1, LLC has 

initiated a new study to replace the prior study which was classified “Supplemental”. The 

plant culture phase of the new study was scheduled to begin June 15, 2015. Applications will 

2015.08.18 08:27:59 -04'00'
2 

begin approximately July 1, 2015 and terminate approx. July 30, 2015 when shoot dry weight 

data is collected. A draft report is targeted for October, 2015 and a final report for December, 

2015.”

EFED Response: EFED is looking forward to reviewing the terrestrial plant, vegetative 

vigor data when it is submitted to the Agency. EFED recommends that care is taken to 

ensure that the study is conducted at the maximum application rate of 0.022 lbs a.i./A. This 

was one of the deviations that resulted in the downgrading of the currently available 

vegetative vigor toxicity study, and there is uncertainty of risk at the maximum application 

rate. In addition, a no-effect concentration level needs to be established; this is especially 

vital for endangered species risk assessments. 

Comment 2: The registrant does not agree with the initial conclusions of the avian 

reproduction study by EFED that were presented in the “EFED Registration Review Problem 

Formulation for Forchlorfenuron Christina Wendel and Greg Orrick, PC Code: 128819, DP 

Barcode: 422524, January 28, 2015.” KIM-C1, LLC cite data presented in the study report 

(Frey LT, Martin KH, Beavers JB, Jaber M. 2014. “Forchlorfenuron: A Reproduction Study 

with the Northern Bobwhite”, MRID No. 49350901). Including the reproduction of Table 6, 

and conclusion section of the report. 

“KIM-C1, LLC respectfully requests EFED to re-examine this issue prior to completing 

the Final Work Plan, and any final conclusions therein, relative to the submitted avian 

reproduction study.”

EFED Response: EFED has completed the final review of the avian reproduction DER 

for bobwhite quail (MRID 49350901). The DER can be found attached to this 

memorandum in Appendix A. Please see EFED’s response to the avian reproduction data 

waiver request (USEPA, 2015; DP 417353) for additional discussion regarding this study. 

References: 

Frey L.T., Martin K.H., Beavers J.B., and Jaber M. (2014). Forchlorfenuron: A Reproduction 

 Study with the Northern Bobwhite. Unpublished study performed by Wildlife 

 International, Ltd., Easton, Maryland. Laboratory report number 248-108. Study 

 sponsored by Degussa AG, Product Line Agriculture, D-83308 Trostberg, Germany. 

 Study completed on December 3, 2003 and report amended on March 21, 2014. 

MRID 49350901. 

United States Environmental Protection Agency (USEPA). 2015. Wendel, C., G. Orrick, E. 

Arnold and B. Anderson. Memorandum “Forchlorfenuron: Response to Data Waiver 

Requests for a Terrestrial Field Dissipation Study and an Avian Reproduction Study AND

Summary of the Review of an Ecotoxicity Study on the Ecological Effects of 

Forchlorfenuron” DP barcode: 316642, 417353, and 420428. Dated August 11, 2015. 

Office of Pesticide Programs, Environmental Fate and Effects Division. Memorandum to 

the Registration Division. 
Data Evaluation Report on the Reproductive Effects of Forchlorfenuron on Avian Species 

Colinus virginianus

PMRA Submission Number {......} EPA MRID Number 49350901 

Page 1 of 15 

Data Requirement: PMRA Data Code {............} 

EPA DP Barcode 420428 

OECD Data Point {............} 

EPA MRID 49350901 

EPA Guideline OCSPP (formerly OPPTS) 850.2300 

Test material: Forchlorfenuron Purity: 96.95% 

Common name: Forchlorfenuron 

Chemical name: IUPAC: Not Reported 

CAS name: N-(2-chloro-4-pyridinyl)-N’-phenylurea 

CAS No.: 68157-60-8 

Synonyms: None Reported

Primary Reviewer: John Marton, Ph.D. Signature: 

Environmental Scientist, CDM Smith Date: 09/13/2014 

Secondary Reviewer: Teri S. Myers, Ph.D. Signature: 

Environmental Scientist, CDM Smith Date: 09/22/2014 

Primary Reviewer: N.E. Federoff Signature:

Wildlife Biologist/USEPA/OPP/EFED/ERB2 Date: 08/5/2015 

EPA PC Code 128819

CITATION: Frey L.T., Martin K.H., Beavers J.B., and Jaber M. 2014. Forchlorfenuron: A Reproduction Study with 

the Northern Bobwhite. Unpublished study performed by Wildlife International, Ltd., Easton, Maryland. 

Laboratory report number 248-108. Study sponsored by Degussa AG, Product Line Agriculture, D-83308 

Trostberg, Germany. Study completed on December 3, 2003 and report amended on March 21, 2014. 

Appendix A. Forchlorfenuron Avian Reproduction DER; MRID 49350901
Data Evaluation Report on the Reproductive Effects of Forchlorfenuron on Avian Species 

Colinus virginianus

PMRA Submission Number {......} EPA MRID Number 49350901 

Page 2 of 15 

EXECUTIVE SUMMARY

The one-generation reproductive toxicity of forchlorfenuron to groups of 16 pairs of 20-week-old Northern bobwhite 

quail (Colinus virginianus) were assessed over 20 weeks. Forchlorfenuron was administered to the birds in the diet at 

nominal concentrations of 0 (negative control), 160, 400, and 1000 mg a.i./kg diet (ppm). Mean-measured 

concentrations in the diet were 170, 435, and 1070 mg a.i./kg diet, respectively. The NOAEC was determined to be 

<170 mg a.i./kg diet based on significant, slightly (7.0-9.1%) dose-dependent reductions (p < 0.05) in 14-d survivor 

weight at the 170, 435, and 1070 mg a.i./kg diet levels when compared to the negative control. 

There were no treatment-related mortalities, abnormal signs of toxicity, or remarkable pathological findings in any 

treatment group relative to the negative control. Further, mean food consumption and sex-specific adult body weight 

gain were comparable between the control and treatment groups. With the exception of 14-d survivor weight, there 

were no other treatment-related effects on any reproductive parameter analyzed. 

This study is classified as supplemental. 

Results Synopsis

Test Organism Size/Avg. (mean Weight): 20 weeks 

NOAEC: <170 mg a.i./kg diet 

LOAEC: 170 mg a.i./kg diet 

Endpoint(s) Affected: 14-d survivor weight 
Data Evaluation Report on the Reproductive Effects of Forchlorfenuron on Avian Species 

Colinus virginianus

PMRA Submission Number {......} EPA MRID Number 49350901 

Page 3 of 15 

I. MATERIALS AND METHODS

GUIDELINE FOLLOWED: This study was conducted following guidelines outlined in the 

Environmental Protection Agency’s Registration Guidelines Pesticide 

Assessment Guidelines, FIFRA Subdivision E, Hazard Evaluation: Wildlife 

and Aquatic Organisms, Subsection 71-4; U.S. Environmental Protection 

Agency Series 850- Ecological Effects Test Guideline OCSPP (formerly 

OPPTS) Number 850.2300; OECD Guideline 206; and the ASTM 

“Standard Practice for Conducting Reproductive Studies with Avian 

Species”. There were no deviations from OCSPP 850.2300 (June 2012) 

noted. 

COMPLIANCE: Signed and dated No Data Confidentiality, GLP, and Quality Assurance 

statements were provided. This study was conducted in compliance with 

Good Laboratory Practice Standards as published by the U.S. 

Environmental Protection Agency, 40 CFR Part 160, 17 August 1989; 

OECD Principles of Good Laboratory Practice (ENV/MC/CHEM(98) 17); 

and Japan MAFF, 11 Nohsan Notification No. 6283. Agricultural 

Production Bureau, 1 October 1999, with the following exceptions: the test 

substance was not characterized in accordance with GLP standards; and, 

stability under storage conditions at the test site was not determined in 

accordance with GLP standards. 

A. MATERIALS:

 1. Test Material Forchlorfenuron 

Description: Powder

Lot No./Batch No. : 97030010 (Batch No.) 

Purity: 96.95% 

Stability of compound 

under test conditions: Mean-measured concentrations were 170, 435, and 1070 mg a.i./kg diet, 

 yielding recoveries of 106, 109, and 107% of nominal. 

(OECD recommends water solubility, stability in water and light, pKa, Pow, and vapor pressure of test 

compound)

Storage conditions of 

test chemicals: Stored under ambient conditions. 

 Physicochemical properties of Forchlorfenuron. 

Parameter Values Comments 

Water solubility at 20°C Not Reported 

Vapor pressure Not Reported

UV absorption Not Reported

pKa Not Reported

Kow Not Reported
Data Evaluation Report on the Reproductive Effects of Forchlorfenuron on Avian Species 

Colinus virginianus

PMRA Submission Number {......} EPA MRID Number 49350901 

Page 4 of 15 

2. Test organism: 

Table 1: Test organism. 

Parameter Details 

Remarks 

Criteria 

Species (common and scientific names): Northern Bobwhite quail, 

(Colinus virginianus) Recommended species include a wild 

waterfowl species, preferably the 

mallard (Anas platyrhynchos) or an 

upland game species, preferably the 

northern bobwhite (Colinus 

virginianus)

Age at Study Initiation: 20 weeks From the same hatch, 

approaching first breeding 

season, and have not been used in 

any previous testing. 

Birds approaching their first 

breeding season should be used.

Body Weight: (mean and range) 170-216 g Weight at test initiation 

Body weights should be recorded at 

test initiation and at biweekly 

intervals up to week eight or up to the 

onset of egg laying and at 

termination.

Source: Trace Pheasantry, 

288 Levengood Rd.

Douglassville, PA, USA All birds should be from the same 

source.

B. STUDY DESIGN:

1. Experimental Conditions 

a. Range-finding study: No range-finding data were reported. 

b. Definitive Study 

 
Data Evaluation Report on the Reproductive Effects of Forchlorfenuron on Avian Species 

Colinus virginianus

PMRA Submission Number {......} EPA MRID Number 49350901 

Page 5 of 15 

Table 2: Experimental Parameters. 

Parameter Details 

Remarks 

Criteria 

Acclimation period: 

Conditions (same as test or not):

Feeding:

Health (any mortality observed):

4 weeks 

Same as test

Diet was provided ad libitum and 

was formulated by Agway Inc., 

and contained at least 27% 

protein, 2.5% fat, and no more 

than 5% fiber. 

Appeared normal and healthy 

prior to testing. 

Phenotypically indistinguishable 

from wild type at start of 

acclimation. Basal diet contained 

approx. 1.1% calcium; however, 

additional limestone is needed for 

breeding birds. Therefore, basal 

diets contained supplemental 

limestone of 5% (w/w); (38.5% Ca) 

for adult birds. 

Recommended observation period 

includes a 2-3 week health observation 

period prior to selection of birds for 

treatment. Generally, birds should be 

healthy without excess mortality. 

Feeding should be ad libitum, and 

sickness, injuries or mortality should be 

noted. 

Test duration 

pre-laying exposure: 

egg-laying exposure: 

withdrawal period, if used:

10 weeks 

(7 weeks pre-photostimulation 

 + 

3 weeks post-photostimulation) 

10 weeks 

N/A

Pre-laying exposure: 

pre-photostimulation - 7 weeks; preegg laying: (w/ photostimulation) – 

3 weeks (7+3 = 10 weeks). 

Egg-laying: Approx. 10 weeks 

Recommended pre-laying exposure 

duration:

At least 10 weeks prior to the onset of 

egg-laying. 

Recommended exposure duration with 

egg-laying:

At least 10 weeks.

Recommended withdrawal period: 

If reduced reproduction is evident, a 

withdrawal period of up to 3 weeks 

should be added to the test phase.
Data Evaluation Report on the Reproductive Effects of Forchlorfenuron on Avian Species 

Colinus virginianus

PMRA Submission Number {......} EPA MRID Number 49350901 

Page 6 of 15 

Parameter Details 

Remarks 

Criteria 

Pen (parental and offspring) 

size:

construction materials:

number:

Adult Pens: 27 x 51 cm; sloping 

floors that resulted in ceiling 

height ranging from 20 to 25 cm. 

Offspring Pens: Hatchlings 

housed in batteries of brooding 

pens 72 x 90 x 23 cm high. 

Adult Pens: Pens were 

constructed of galvanized wire 

mesh and galvanized sheeting. 

Offspring Pens: External walls 

and ceilings were constructed of 

galvanized wire mesh and 

galvanized sheeting; floors were 

of galvanized wire mesh.

Adult Pens: 16 pens per treatment 

with one male and one female in 

each pen. 

Offspring Pens: 

Adult Pens: GQFM Model No. 0330 

Offspring Pens: Beacon Steel Co. 

Model B735Q

Pens 

Pens should have adequate room and 

be arranged to prevent crosscontamination.

Materials

Recommended materials include 

nontoxic material and nonbinding 

material, such as galvanized steel. 

Number

At least 5 replicate pens should be used 

for mallards housed in groups of 7. For 

other arrangements, at least 12 pens 

should be used, but considerably more 

may be used if birds are kept in pairs. 

Chicks should be housed according to 

parental grouping.

Number of birds per pen (male:female) One male and one female Sex of birds were determined by a 

visual examination of plumage. 

One male and one female per pen 

should be used. For quail, one male 

and two females should be used. For 

ducks, two males and five females 

should be used.

Number of pens per group/treatment 

negative control:

solvent control:

treated:

16

N/A

16

At least 12-16 pens should be used, but 

considerably more if birds are kept in 

pairs. 

Test concentrations (mg a.i./kg diet) 

nominal:

measured:

0 (negative control), 160, 400, 

and 1000 mg a.i./kg diet 

0, 170, 435, and 1070 mg a.i./kg 

diet (mean-measured) 

Recommended test concentrations 

include at least two concentrations 

other than the control; three or more 

will provide a better statistical analysis. 

The highest test concentrations should 

show a significant effect or be at or 

above the actual or expected field 

residue level.
Data Evaluation Report on the Reproductive Effects of Forchlorfenuron on Avian Species 

Colinus virginianus

PMRA Submission Number {......} EPA MRID Number 49350901 

Page 7 of 15 

Parameter Details 

Remarks 

Criteria 

Maximum labeled field residue 

anticipated and source of information: 

Not reported 

The highest test concentrations should 

show a significant effect or be at or 

above the actual or expected field 

residue level. The source (i.e., 

maximum label rate in lb a.i./A and 

ppm), label registration no., label date, 

and site should be cited]

Solvent/vehicle, if used 

type:

amount:

N/A; a solvent was not used

Recommended solvents include corn oil 

or other appropriate vehicle not more 

than 2% of diet by weight

Was detailed description and nutrient 

analysis of the basal diet provided 

(Yes/No)

Yes A commercial breeder feed or an 

equivalent that is appropriate for the 

test species is recommended.

Preparation of test diet Test diets were prepared by 

mixing forchlorfenuron into a 

premix that was used for weekly 

preparation of the diet. Control 

and treatment diets were prepared 

weekly and were adjusted for the 

purity of the test material. 

A premixed diet containing the test 

substance should be mechanically 

mixed with basal diet. If an evaporative 

vehicle is used, it should be completely 

evaporated prior to feeding.

Indicate whether stability and 

homogeneity of test material in diet 

determined (Yes/No) 

Yes

Were concentrations in diet verified by 

chemical analysis? Yes LOD=1.0 μg a.i./mL = 50.0 ppm a.i 

LOQ = 75.0 ppm a.i. 

Did chemical analysis confirm that diet 

was stable and homogeneous? Yes

Feeding and husbandry Feeding and husbandry conditions 

appeared to be adequate, given 

guideline recommendations.

Basal diets contained supplemental 

limestone 5% (w/w); (38.5% Ca) 

for adult birds. For offspring the 

basal diet did not contain either the 

test substance or the additional 

supplemental limestone. 
Data Evaluation Report on the Reproductive Effects of Forchlorfenuron on Avian Species 

Colinus virginianus

PMRA Submission Number {......} EPA MRID Number 49350901 

Page 8 of 15 

Parameter Details 

Remarks 

Criteria 

Test conditions (pre-laying) 

temperature:

relative humidity:

photoperiod:

20.6 ± 1.3°C (SD) 

31 ± 11% (SD) 

8L: 8D for acclimation and the 

first seven weeks of the test; then 

it increased to 17L: 7D (at 

beginning of week 8 to induce 

egg laying – maintained at that 

length until adult birds were 

euthanized) 

Throughout the test, birds received 

a mean of approx. 217 lux (~20 foot 

candles) of illumination by 

fluorescent lights – closely 

approximated noon-day sunlight. 

The air handling system in study 

room – designed to vent up to 15 

room air volumes every hour and 

replace them with fresh air. 

Recommended temperature: 

about 21°C (70°F) 

Recommended relative humidity:

about 55%

Recommended lighting

First 8 weeks: 7 h per day.

Thereafter: 16-17 h per day. 

At least 6 foot-candles are 

recommended at bird level.

Egg Collection and Incubation

Egg collection and storage: 

collection interval:

storage temperature:

storage humidity:

Incubation: 

temperature:

humidity:

Daily

14.0 ± 0.1°C (SD) – mean temp. 

81 ± 6% (SD) – mean relative 

humidity

37.0 ± 0.0°C (SD) – avg. temp. 

54 ± 0.4% (SD) – avg. relative 

humidity

Collected daily from all pens, when 

available. Eggs were stored in a 

cold room until incubation. All eggs 

laid in a weekly interval were 

considered as one lot.

NatureForm Incubator (Model No. 

NMC-4000 or NMC-7000), 

equipped with pulsator fan and 

blades –produced mild breathing 

movement; also equipped w/ 

automatic egg rotation device 

designed to rotate eggs 90q every 

hour through 21 days of incubation. 

Eggs should be collected daily; 

recommended egg storage temperature 

is approximately 16°C (61°F); 

recommended humidity is 

approximately 65%.

Recommended collection interval: daily
Data Evaluation Report on the Reproductive Effects of Forchlorfenuron on Avian Species 

Colinus virginianus

PMRA Submission Number {......} EPA MRID Number 49350901 

Page 9 of 15 

Parameter Details 

Remarks 

Criteria 

Were eggs candled for cracks prior to 

setting for incubation?

Were eggs set weekly?

Yes

Yes

Speed King (Model No. 32) eggcandling lamp, eggs to be incubated 

were fumigated with formaldehyde 

gas. Placed into a NatureForm 

Incubator (Model No. NMC-4000 

or NMC-7000) 

Eggs should be candled on day 0

When candling was done for fertility? Eggs were candled on Day 11-12 

of incubation to determine 

embryo viability and on Day 21 to 

determine embryo survival.

Speed King (Model No. 32) eggcandling lamp. 

Quail: approx. day 11 

Ducks: approx. day 14

When the eggs were transferred to the 

hatcher?

Day 21 Petersime Hatcher (Model No. 

S6H) 

Bobwhite: usually day 21 

Mallard: usually day 23

Hatching conditions 

temperature:

humidity:

photoperiod: 

37.2 ± 0.0°C (SD) – avg. temp. in 

hatching compartment; 33.3 ± 

0.0% (SD) – avg. wet bulb temp. 

77%

Not Reported 

Eggs were not rotated in the hatcher 

Recommended temperature is 39°C 

(102°F) 

Recommended humidity is 70%

Day the hatched eggs were removed and 

counted

Day 25 or 26 All hatchlings, unhatched eggs, and 

egg shells were removed from 

hatcher. 

Eggs for bobwhite should be removed 

on day 24; for mallard on day 27

Egg shell thickness 

no. of eggs used:

intervals:

mode of measurement:

One egg, when available, from 

each group

Weekly

Five points around the waist of 

the shell using a micrometer 

calibrated to 0.002 mm. 

Opened at waist, contents removed, 

rinsed with water, and air dried for 

at least 1 week. 

Newly hatched eggs should be collected 

at least once every two weeks. 

Thickness of the shell plus membrane 

should be measured to the nearest 0.01 

mm with 3 - 4 measurements per shell.

Were egg shells washed and dried for at 

least 48 hrs. before measuring? 

Yes, shells were dried for at least 

one week 
Data Evaluation Report on the Reproductive Effects of Forchlorfenuron on Avian Species 

Colinus virginianus

PMRA Submission Number {......} EPA MRID Number 49350901 

Page 10 of 15 

Parameter Details 

Remarks 

Criteria 

Brooding Chambers 

temperature:

humidity:

photoperiod: 

27.3 ± 1.1°C (SD) – avg. ambient 

room temp.

21 ± 8% (SD) – avg. relative 

humidity

16 hours light per day 

Thermostats in brooding compartment 

of each pen were set to maintain a 

temperature of approx. 38°C from 

time of hatching until birds were 14 

days old.

Reference chemical, if used N/A; a reference chemical was 

not used

2. Observations: 

Table 3: Observations. 

Parameter Details Remarks 

Parameters measured

Parental 

(mortality, body weight, mean feed 

consumption)

Egg collection and subsequent 

development

(no. of eggs laid, no. of eggs 

cracked, shell thickness, no. of eggs 

set, no. of viable embryos, no. of 

live 3 week embryos, no. hatched, 

no. of 14-day survivors, average 

weight of 14-d old survivors, 

mortality, gross pathology, others) 

-Mortality

-Signs of toxicity

-Body weight

-Feed consumption 

- eggs laid

- eggs cracked

- egg weight

- egg shell thickness

- eggs set

- viable embryos

- live 3-week embryos 

- hatchlings

- hatchling body weight

- 14-day-old survivors 

- 14-day-old survivor body weight 

Recommended endpoints measured 

include:

x Eggs laid/pen 

x Eggs cracked/pen 

x Eggs set/pen 

x Viable embryos/pen 

x Live 3-week embryos/pen 

x Normal hatchlings/pen 

x 14-day-old survivors/pen 

x 14-day-old survivors/pen 

x Weights of 14-day-old 

x survivors (mean per pen) 

x Egg shell thickness 

x Food consumption (mean per 

pen) 

x Initial and final body weight 

(mean per pen)

Indicate if the test material was 

regurgitated 

None reported 
Data Evaluation Report on the Reproductive Effects of Forchlorfenuron on Avian Species 

Colinus virginianus

PMRA Submission Number {......} EPA MRID Number 49350901 

Page 11 of 15 

Parameter Details Remarks 

Observation intervals (for various 

parameters)

Birds were observed daily for signs 

of toxicity and abnormal behavior. 

Additionally, all offspring were 

observed daily from hatching until 

14 days of age. Adult body weights 

were measured at test initiation, on 

weeks 2, 4, 6, 8, and at termination. 

Feed consumption from each pen 

was measured weekly throughout 

the test. 

Body weights and food consumption 

should be measured at least biweekly

Were raw data included? Yes 

II. RESULTS AND DISCUSSION:

A. MORTALITY: 

No treatment-related mortalities occurred in the control or treatment groups throughout the test. One incidental 

death occurred in the highest treatment group. On Day 2 of Week 12 one female was found dead and prior do 

death was noted to have a head lesion and feather loss. At necropsy the bird was well muscled and had a body 

weight of 181 grams. Externally, the bird was noted with a laceration at the back of the head and along the 

dorsal surface of the neck. Internally, a hematoma at the back of the head and neck, and a neck fracture at C1 

were noted. A hematoma was also noted on the inner left thigh. The spleen and kidneys were slightly pale, the 

cecal contents were firm, and the ovary was developing. No other lesions were noted and necropsy of the male 

pen mate was unremarkable. This single mortality was not considered to be treatment related and the study 

authors reported a NOAEC of 1000 mg a.i./kg diet 

Table 4: Effect of Forchlorfenuron on Mortality of Northern Bobwhite Quail (Colinus virginianus).

Mean-Measured and (Nominal) 

Concentrations 

mg a.i./kg diet (ppm a.i.) 

Observation Period 

Week 1 Week 12 Week 20 

No. Dead 

Male Female 

No. Dead 

Male Female 

No. Dead 

Male Female 

Negative Control 0 0 0 0 0 0 

170 (160) 0 0 0 0 0 0 

435 (400) 0 0 0 0 0 0 

1070 (1000) 0 0 0 1 0 1 

 
Data Evaluation Report on the Reproductive Effects of Forchlorfenuron on Avian Species 

Colinus virginianus

PMRA Submission Number {......} EPA MRID Number 49350901 

Page 12 of 15 

B. REPRODUCTIVE AND OTHER ENDPOINTS: 

Abnormal Effects/Behavior: No overt signs of toxicity were noted in any treatment group. Incidental clinical 

observations were made and included those normally associated with injuries and penwear. Such observations 

included head and foot lesions, ocular injury, an abscess on the head, feather loss, feather picked, nostril picked, 

and a general pen-worn appearance. Clinical observations, usually associated with the incidental injuries included 

lameness. Except for these incidental findings, all birds appeared normal throughout the study. 

Food Consumption: There were no significant treatment-related differences in weekly feed consumption at any 

treatment level. Overall mean feed consumption ranged from 18 to 19 g/bird/day for all control and treatment 

groups. The study authors reported a NOAEC of 1000 mg a.i./kg diet. 

Body Weights: There were no treatment-related effects on adult body weight for either sex throughout the test. 

Mean male body weight ranged from 186 to 191 g and from 201 to 207 g at test initiation and termination, 

respectively. Mean female body weight ranged from 187 to 190 g and from 227 to 234 g at test initiation and 

termination, respectively. The study authors reported a NOAEC of 1000 mg a.i./kg diet. 

The study authors noted significant reductions in hatchling body weight at the 400 and 1000 mg a.i./kg diet 

treatment groups relative to the control. However, the differences were slight (approximately 0.5 g; 8%) and were 

not concentration responsive. Therefore, the study authors did not consider these reductions to be treatmentrelated. The study authors reported a NOAEC of 1000 mg a.i./kg diet. 

Reproductive Effects: There were no apparent treatment-related effects on any reproductive parameter or eggshell 

thickness at any treatment level relative to the negative control. The study authors reported a NOAEC of 1000 mg 

a.i./kg diet. 

 
Data Evaluation Report on the Reproductive Effects of Forchlorfenuron on Avian Species 

Colinus virginianus

PMRA Submission Number {......} EPA MRID Number 49350901 

Page 13 of 15 

Table 5: Reproductive and Other Parameters (nominal concentrations; mg/kg-diet) 

Parameter Control 100 400 1000 NOAEC/ 

LOAEC 

No. laying pairs 16 16 16 16 N/A 

Eggs laid/pen 41 42 40 40 1000/>1000 

Eggs laid/hen/day(a) 0.44 0.46 0.43 0.44 1000/>1000 

Eggs cracked 6 12 8 15 1000/>1000 

Eggs set 552 588 546 514 1000/>1000 

Shell thickness (mm ± SD) 0.230±0.012 0.228±0.014 0.221±0.018 0.229±0.013 1000/>1000 

Viable embryos 520 509 492 460 1000/>1000 

Live 3-week embryos 512 507 485 456 1000/>1000 

No. of hatchling/hen 469 478 451 435 1000/>1000 

Hatchling weight (g) 5.9 5.8 5.4* (b) 5.5* (b) 1000/>1000 

14-day old survivors 437 434 408 380 1000/>1000 

14-day old survivors weight (g) 25 24 23 23 1000/>1000 

Mean food consumption 

(g/bird/day) 18 18 19 18 1000/>1000 

Weight of females (g; parent) 

at test initiation: 

at test termination: 

190

234 

187 

230 

189 

232 

189

227 

1000/>1000 

Weight of males (g; parent) 

at test initiation: 

at test termination: 

191

207 

186 

201 

190 

204 

190

202 

1000/>1000 

Gross pathology None considered treatment-related 

(a) Based on 92 days of egg production 

(b) Not considered treatment-related 

* Significantly reduced from control (p < 0.05). 

C. REPORTED STATISTICS: 

Adult sex-specific body weight, mean food consumption, and reproductive parameters were analyzed using 

ANOVA. Dunnett’s multiple comparison procedure was used to compare the three treatment means with the 

control group mean and assess the statistical significance of the observed differences. Sample units were the 

individual pens within each experimental group, except adult body weights were the sample unit was the 

individual bird. Percentage data were examined using Dunnett’s method following acrsine square root 

transformations. Percentage data included the following endpoints: eggs laid of maximum laid, eggs cracked of 

eggs laid, viable embryos of eggs set, live 3-week embryos of viable embryos, hatchlings of 3-week embryos, 

14-d old survivors of hatchings, hatchlings of eggs set, 14-d old survivors of eggs set, hatchlings of maximum 

set, and 14-d old survivors of maximum set. 
Data Evaluation Report on the Reproductive Effects of Forchlorfenuron on Avian Species 

Colinus virginianus

PMRA Submission Number {......} EPA MRID Number 49350901 

Page 14 of 15 

D. VERIFICATION OF STATISTICAL RESULTS: 

Statistical Method: The reviewer analyzed eggs laid per, eggs not cracked per egg set, viable embryos per egg 

set, live embryos per egg set, hatchlings per egg set, 14-d survivors per egg set, live embryos per viable embryo, 

hatchlings per live embryo, 14-survivors per normal hatchling, eggshell thickness, and sex-specific adult body 

weight change. Prior to determining NOAEC values all data were tested for normality using the Shapiro-Wilk’s 

(α=0.01) test and for homogeneity of variance using Levene’s test (α=0.01). Eggs laid per pen, eggshell 

thickness, and mean food consumption met the assumptions of ANOVA and were analyzed using Dunnett’s test. 

Male weight gain, hatchling weight, and survivor weight also exhibited a suggestive monotonically decreasing 

trend and was therefore also analyzed using the Williams (14-d survivor weight, male weight gain) or the 

Jonckheere-Terpstra (hatchling weight) test. All remaining endpoints were analyzed using Wilcoxon/Bonferroni 

Adjustment test. All analyses were conducted using CETIS statistical software version 1.8.7.12 with database 

backend settings implemented by EFED on 3/25/2014. All analyses were conducted using the mean-measured 

concentrations, and the α level was set to 0.05 unless specified otherwise. 

NOAEC: <170 mg a.i./kg diet 

LOAEC: 170 mg a.i./kg diet 

Most Sensitive Endpoint(s): 14-d survivor weight 

Table 6: Reproductive and Other Parameters (mean-measured concentrations, mg a.i./kg diet). 

Parameter Control 170 435 1070 NOAEC/ 

LOAEC 

Eggs laid/pen 40.6 42.0 39.9 40.2 1070/>1070 

Eggs not cracked/eggs laid (%) 99.1 98.1 98.9 97.0 1070/>1070 

Viable embryos/eggs set (%) 93.9 87.0 87.2 89.7 1070/>1070 

Live embryos/eggs set (%) 92.0 86.2 85.7 89.0 1070/>1070 

Hatchlings/eggs set (%) 83.7 82.4 78.6 84.9 1070/>1070 

14-d hatchlings/eggs set (%) 76.2 73.2 69.6 75.6 1070/>1070 

Live embryos/viable embryos (%) 97.8 99.1 97.3 98.8 1070/>1070 

Hatchlings/live embryos (%) 90.8 95.8 90.9 95.7 1070/>1070 

14-d hatchlings/normal hatchlings (%) 90.1 88.0 90.0 88.9 1070/>1070 

Eggshell thickness (mm) 0.229 0.228 0.221 0.229 1070/>1070 

Hatchlings weight (g) 5.75 5.73 5.44 5.47 1070/>1070 

14-d survivor weight (g) 25.4 23.6* 23.1* 23.1* <170/170 

Mean food consumption (g/bird/day) 17.8 17.7 18.6 17.8 1070/>1070 

Male weight gain (g) 16.1 14.9 14.1 11.6 1070/>1070 

Female weight gain (g) 44.6 42.4 43.1 38.9 1070/>1070 

* Significant reduction relative to the negative control (William’s test, p < 0.05) 
Data Evaluation Report on the Reproductive Effects of Forchlorfenuron on Avian Species 

Colinus virginianus

PMRA Submission Number {......} EPA MRID Number 49350901 

Page 15 of 15 

E. STUDY DEFICIENCIES: 

There were no study deficiencies.

F. REVIEWER’S COMMENTS: 

The reviewer’s results were based on the mean-measured concentrations whereas those of the study authors were 

based on nominal concentrations. Further, the study authors did not consider the significant reductions in 14-d 

survivor body weight to be treatment-related. The reviewer detected significant reductions in 14-d survivor body 

weight at all treatment levels (7.0-9.1%) relative to the negative control and these reductions followed a mildlysuggestive dose-dependent pattern. Therefore, the reviewer’s results are reported in the Executive Summary and 

Conclusions sections of this DER. 

Homogeneity of the test substance in the diet was evaluated by collection of six samples from each of the treated 

diets and one sample from the control diet on Day 0 of Week 1. Samples were collected from the top, middle, and 

bottom of the left and right sections of the mixing vessel. Control and treatment group diet samples were also 

collected from the feed troughs on Day 7 of Week 1 to assess stability of the test substance under actual test 

conditions. None of the control samples showed any indication of the presence of the test substance or of the 

presence of co-eluting substances. Means and standard deviations for the three concentrations were 170 ± 5.24, 

432 ±5.56, and 1060 ±16.4 mg a.i./kg diet, with coefficients of variation of 3.08, 1.29, and 1.55%, respectively. 

A sample was also collected from the control and treatment group diets during Weeks 2, 3, 4, 8, 12, 16, and 20 of 

the test to measure/verify test concentrations. Means and standard deviations were 170 ± 7.90, 435 ± 7.66, and 

1070 ± 35.3 mg a.i./kg diet, with coefficients of variation of 4.65, 1.76, and 3.30%, respectively. Mean measured 

concentrations yielded recoveries of 106 to 109% of nominal. 

The in-life portion of the definitive toxicity test was conducted from October 16, 2002 to April 14, 2003. 

G. CONCLUSIONS: 

This study is scientifically sound but is classified as supplemental because a valid NOAEC was not established. 

The NOAEC and LOAEC were <170 and 170 mg a.i./kg diet, respectively, based on significant and suggestively 

dose-dependent inhibitions in 14-d survivor weight at all treatment levels relative to the negative control. 

NOAEC: <170 mg a.i./kg diet 

LOAEC: 170 mg a.i./kg diet 

Endpoint(s) Affected: 14-d survivor weight 

III. REFERENCES: 

Merck & Co., Inc. 1991. The Merck Veterinary Manual. Merck & Co. Rahway, NJ. 1832 pp. 

Dunnett, C.W. 1955. A Multiple Comparison’s Procedure for Comparing Several Treatments with a Control. Jour. 

Amer. Statis. Assoc. 50: 1096-1121. 

Dunnett, C.W. 1964. New Tables for Multiple Comparisons with a Control. Biometrics 20:482-491.