Document ID: EPA-HQ-OPP-2011-0374-0025
Agency: epa
Document Type: Supporting & Related Material
Title: 
Posted Date: 2022-04-28T04:00Z

﻿
Data Requirement:PMRA Data Code:9.8.4 (TGAI) or 9.8.6 (EP)
                        EPA DP Barcode:420822
                        OECD Data Point:IIA 8.12 (TGAI) and IIIA 10.8.1.1 (EP)
                        EPA Guideline:850.4150

Test material:  Dacthal Flowable Herbicide (DCPA)Purity:54.0%
Common name:  
Chemical name:IUPAC:
CAS name:  
CAS No.:   1861-32-1
Synonyms:  DCPA
Primary Reviewer:Teresa NelisSignature:  
Environmental Scientist, CDM/CSS-Dynamac JVDate: 12/22/16

Secondary Reviewer:  Teri MyersSignature:  
Senior Scientist, CDM/CSS-Dynamac JVDate:   12/22/16

Primary Reviewer:Christina M. WendelSignature: 
EPA/OPP/EFED/ERB2/Biologist Date: 12/02/2021

Secondary Reviewer(s): Michael WagmanSignature: 
EPA/OPP/EFED/ERB2/Senior ScientistDate: 11/30/2021

Reference/Submission No.: {.....................}

Company Code {............}[For PMRA]
Active Code{............}[For PMRA] 
Use Site Category:{............}[For PMRA]
EPA PC Code 078701

Date Evaluation Completed: 02-12-2021

CITATION:  Sindermann, A.B., Porch, J.R, Krueger, H.O. and K.H. Martin, K.H. 2013. Dacthal: A Toxicity Test to Determine the Effects of the Test Substance on Vegetative Vigor of Ten Species of Plants. Final Report. Unpublished study performed by Wildlife International, Easton, Maryland. Study sponsored by Amvac Chemical Corporation. Los Angeles, California. Wildlife International Project Number 246P-106. Study completed December 6, 2013.

This Data Evaluation Record may have been altered by the Environmental Fate and Effects Division subsequent to signing by CDM/CSS-Dynamac JV personnel

EXECUTIVE SUMMARY:

The effect of Dacthal Flowable Herbicide (DCPA) on the vegetative vigor of monocot (corn, Zea mays; onion, Allium cepa; ryegrass, Lolium perenne; and wheat, Triticum aestivum) and dicot (cabbage, Brassica oleracea; lettuce, Lactuca sativa; oilseed rape, Brassica napus; soybean, Glycine max; sugarbeet, Beta vulgaris; and tomato, Lycopersicon esculentum) crops was studied at nominal concentrations of 0 (negative control), 0.66, 1.3, 2.6, 5.2, and 10.5 lb ai/A. 

Treatment levels were analytically confirmed in the dosing solutions at each application rate. The measured concentrations of DCPA were <0.089 (<LOQ, negative control), 0.61, 1.23, 2.52, 4.98, and 10.2 lb a.i./A for onion, ryegrass, soybean, sugarbeet, and tomato, and <0.089 (<LOQ, negative control), 0.61, 1.24, 2.53, 5.08, 10.2 lb a.i./A for cabbage, corn, lettuce, oilseed rape, and wheat.

The growth medium used in the seedling emergence test was a loamy sand made from kaolinite clay, industrial quartz sand and peat (loamy fine sand, pH 7.2, organic carbon 0.56%). On day 21 the surviving plants per pot were recorded and cut at soil level for measuring the plant height and dry weight. 

Negative control survival was 100%. There were no significant inhibitions in seedling survival in any species tested compared to the negative control (p>0.05). 

There were no significant inhibitions in seedling height in any species tested compared to the negative control (p>0.05). 
      
There were no significant inhibitions in dry weight for any species tested except for soybean. Significant inhibitions in soybean dry weight were 19 and 20% at the 4.98 and 10.2 lb a.i./A treatment levels, respectively, compared to the negative control (Dunnett's test, p<0.05). 

Based on the reviewer's results, the most sensitive monocot could not be determined due to lack of toxicity. Inhibitions did not approach 25% and there were no statistically significant effects for any monocot tested. Therefore, the IC25 was visually estimated as >10.2 lb a.i./A, the highest tested application rate, and the NOAEC was 10.2 lb a.i./A for all tested monocot species. The most sensitive dicot was soybean, based on dry weight, with NOAEC and extrapolated IC25 values of 2.52, and 11.9 lb a.i./A, respectively (with 20% effects at the 10.2 lb a.i./A, highest test level); however, the IC25 value and confidence intervals were outside the tested range of concentrations and should be interpreted with caution.  

Based on the phytotoxicity rating system used by the study author, there were no to slight effects in all species.  Soybean and sugarbeet phytotoxic effects included chlorosis, necrosis and leaf curl, and the effects were dose-related.

Maximum Labeled Rate: Not reported

Monocot
   Most sensitive monocot:Could not be determined due to lack of toxicity
   
   EC50/IC50: >10.2 lb a.i./A95% C.I.: N/A
   EC25/IC25: >10.2 lb a.i./A95% C.I.: N/A
   EC05/IC05: N/A95% C.I.: N/A
   NOAEC: 10.2 lb a.i./A
   LOAEC: >10.2 lb a.i./A
   Slope: N/A95% C.I.: N/A

Dicot
   Most sensitive dicot:   Soybean, based on dry weight*
   
   EC50/IC50: >10.2 lb a.i./A 95% C.I.: N/A
   EC25/IC25: 11.9 lb a.i./A95% C.I.: 5.96-20.1 lb a.i./A
   EC05/IC05: 2.72 lb a.i./A95% C.I.: N/A-5.56 lb a.i./A
   NOAEC: 2.52 lb a.i./A
   LOAEC: 4.98 lb a.i./A
   Slope: N/A95% C.I.: N/A
   *Some endpoints and/or confidence intervals are outside the tested range of concentrations and should be interpreted with caution.

Table 1 (Tier II studies).  Summary of most sensitive parameters by species (lb ai/A).
Species
Endpoint
NOEC
EC05/IC05
EC25/IC25
EC50/IC50
Cabbage
None
10.2
NC
>10.2
>10.2
Corn
None
10.2
>10.2
>10.2
>10.2
Lettuce
None
10.2
NC
>10.2
>10.2
Oilseed Rape
None
10.2
NC
>10.2
>10.2
Onion
None
10.2
NC
>10.2
>10.2
Ryegrass
None
10.2
NC
>10.2
>10.2
Soybean1*
Dry Weight
2.52
2.72
11.9
>10.2
Sugarbeet
None
10.2
NC
>10.2
>10.2
Tomato
None
10.2
>10.2
>10.2
>10.2
Wheat
None
10.2
NC
>10.2
>10.2
NC  -  not calculable
*Endpoints and/or confidence intervals are outside the tested range of concentrations and should be interpreted with caution.
1Significant inhibitions in soybean dry weight were <25%; and were 19 and 20% at the 4.98 and the 10.2 lb a.i./A treatment levels, respectively, compared to the negative control (Dunnett's test, p<0.05). 

This study is scientifically sound and is classified as acceptable.

I. MATERIALS AND METHODS
  GUIDELINE FOLLOWED:  This study was conducted in compliance with Series 850-Ecological Effects Test Guidelines, OCSPP Number 850.4150: Vegetative Vigor (2012). The reviewer evaluated the study methods according to EPA Ecological Effects Test Guidelines, OCSPP Guideline 850.4150: Vegetative Vigor (January 2012).
                              
The physico-chemical properties of the test material were not reported. This is a minor deficiency.
Soil CEC and % moisture were not reported. This is a minor deficiency.
A range-finding study was conducted, but only the summary results were reported in Appendix 16 of the study report, and some details were not provided in the data summary tables that were provided in the Appendix.
      
   The deficiencies did not have an impact on the acceptability of this study.
   
   COMPLIANCE: Signed and dated GLP, Quality Assurance and Data Confidentiality statements were provided.  This study was conducted in compliance with Good Laboratory Practice Standards as published by U.S. Environmental Protection Agency (40 CFR Part 160), August 1989; OECD Principles of Good Laboratory Practice (ENV/MC/CHEM (98) 17); and Japan MAFF, 59 NohSan, Notification No. 6283, Agricultural Production Bureau, 1 October 1999. As noted, periodic analyses of well water and soil for potential contaminants were not performed according to GLP but were performed using a certified laboratory and standard U.S. EPA analytical methods. Characterization of the reference substance and the stability of the reference substance under conditions of storage at the test site were determined before the completion of the study in accordance with GLP, however, characterization was conducted after test initiation.
   
   A. MATERIALS:

   1. Test Material       DCPA (Dacthal Flowable Herbicide)
   
      Description: Off-white liquid
      
      Lot No./Batch No.: BT2242030
      
      Purity: 54.0%

      Stability of compound 
      under test conditions:Recovery of test substance in spray solutions ranged from 92-97% (n=18); matrix fortified sample recoveries ranged from 99-100%. Stability (verification) of the test material was reported to be 92.7 to 96.4% of nominal concentrations.
      (OECD recommends chemical stability in water and light) 

      Storage conditions of 
      test chemicals: At ambient room conditions, out of direct sunlight.

Table 2.  Physical/chemical properties of DCPA.
Parameter
Values
Comments
Water solubility at 20˚C
Not reported

Vapor pressure
Not reported

UV absorption
Not reported

pKa
Not reported

Kow
Not reported

   
   2. Test organism:

      Monocotyledonous species: Corn (Zea mays, Poaceae; Nothstine Dent); Onion (Allium cepa, Liliaceae; Yellow Granex Hybrid 33); Ryegrass (Lolium perenne, Poaceae; Gator 3 Perennial); and Wheat (Triticum aestivum, Poaceae; Glenn Hard Red Spring). EPA recommends four monocots in two families, including corn.
      Dicotyledonous species: Cabbage (Brassica oleracea, Brassicaceae; Late Flat Dutch); Lettuce (Lactuca sativa, Asteraceae; Summertime); Oilseed Rape (Brassica napus, Brassicaceae; Dwarf Essex); Soybean (Glycine max, Fabaceae; Maverick); Sugarbeet (Beta vulgaris, Chenopodiaceae; 38WVR0852); and Tomato (Lycopersicon esculentum, Solanaceae; Rutgers). EPA recommends six dicots in four families, including soybean and a root crop. 
      OECD recommends a minimum of three species selected for testing, at least one from each of the following categories: Category 1: ryegrass, rice, oat, wheat, and sorghum; Category 2: mustard, rape, radish, turnip, and Chinese cabbage; Category 3: vetch, mung bean, red clover, fenugreek, lettuce, and cress.
      Seed source: Corn, Wheat and Oilseed Rape from Johnny's Selected Seeds, Winslow ME; Onion from Park Seed Company, Greenwood, SC; Ryegrass, Cabbage and Tomato from Meyer Seed, Baltimore, MD;; Lettuce from Sustainable Seed Company, Covelo, CO; Soybean from Missouri Foundation Seeds, Columbia, MO; and Sugarbeet from Betaseed, Inc., Moorhead, MN.  
      Prior seed treatment/sterilization: None. 
      Historical % germination of seed: Corn (94%), Onion (98%), Ryegrass (90%), Wheat (94%), Cabbage (85%), Lettuce (98%), Oilseed Rape (96%), Soybean (91%), Sugarbeet (98%), and Tomato (90%).
Seed storage, if any: Not reported.

   B. STUDY DESIGN:

      1. Experimental Conditions  

         a. Limit test: None. 
         
         b. Range-finding study: A preliminary non-GLP range-finding test evaluating the effects of Dacthal on the height, plant condition and fresh weight was conducted exposing corn, onion, ryegrass, wheat, cabbage, lettuce, oilseed rape, soybean, sugarbeet, and tomato to nominal application rates of 0.016, 0.08, 0.4, 2, and 10 lb a.i./A, and a control. The results are presented in Appendix 16 (pg. 155-164). Fresh weight inhibitions maximum of 87% were observed; and height inhibitions were a maximum of 32% were observed both for onion. Very limited information is provided in the study report, only data summary tables in Appendix 16. 

         c. Definitive Study
         
Table 3:  Experimental Parameters  -  Vegetative Vigor.
Parameters
Vegetative Vigor

Details
Remarks

Criteria
Duration of the test
21 days

Recommended test duration is 14-21 days.
OECD recommends that the test be terminated no sooner than 14 days after 50 percent of the control seedlings have emerged
Number of seeds/plants/species/ replicate
Six pots (replicates) with 5 seeds per replicate

Five plants per replicate are recommended.
Number of plants retained after thinning
Up to 3 seeds were planted in each pot. One day prior to application, seedlings were thinned to one plant per pot, if necessary.
Seedlings were randomly assigned to test groups prior to application.
Number of replicates
Control:
Adjuvant control:
Treated:

6
N/A
6

Four replicates per dose should be used.
OECD recommends a minimum of four replicates per treatment
Test concentrations (lb ai/A)
Nominal:

Measured:  

0 (negative control), 0.66, 1.3, 2.6, 5.2, and 10.5 lb a.i./A

Onion, ryegrass, soybean, sugarbeet, and tomato:
<0.089 (<LOQ, negative control), 0.61, 1.23, 2.52, 4.98, and 10.2 lb a.i./A 

Cabbage, corn, lettuce, oilseed rape, and wheat:
<0.089 (<LOQ, negative control), 0.61, 1.24, 2.53, 5.08, 10.2 lb a.i./A
The study author reported nominal application rates of 0 (negative control), 0.88, 1.8, 3.5, 7.0 and 14 pt/A. Spray solutions were prepared in well water purified by reverse osmosis (R/O). 
Negative control group was sprayed with reverse osmosis water only. 

Measured application rates and conversions are provided in Appendix 1 below.

Five test concentrations should be used with a dose range of 2X or 3X progression

OECD recommends three concentrations, preferably with application rates equivalent to 0.0 (control), 1.0, 10.0 and 100 mg substance per kg of oven-dried soil.
Method and interval of analytical verification

LOQ:
LOD:
Samples of the dosing solutions were analyzed by Agilent Series 1100 High Performance Liquid Chromatograph, YMC-Pack ODS-AM column (150mm) with an Agilent 1100 Series Variable Wavelength Detector (220nm).
0.089 lb a.i./A
N/A
Samples for verification of the spray mixture were collected on September 5 and 6, 2013 and were found to be 92.7 to 96.4% of nominal concentrations (Table 1 in study report; pg. 21).
Adjuvant (type, percentage, if used)
N/A

Test container (pot)
Size/Volume
Material: (glass/polystyrene)

11 cm diameter by 10 cm depth
Plastic

Non-porous containers should be used.
OECD recommends that non-porous plastic or glazed pot be used.
Growth facility
Greenhouse

Method/depth of seeding
Corn, onion, wheat and soybean: 20mm depth
All others: 10mm depth 

Test material application
Application time including the plant growth stage

Number of applications 

Application interval

Method of application

Onion, 2 leaf stage; corn, cabbage, lettuce, 2-4 leaf stage; wheat, 3 leaf stage; sugarbeet, oilseed rape, soybean, tomato, 3-4 leaf stage; ryegrass, 5-8 leaf stage

1

N/A- single application

The test material was applied at 200L/ha using a DeVries Research Track sprayer with a Teejet 8002E nozzle, 20 psi, applied 41 cm from the soil surface. Calibrations of sprayer system indicated actual spraying rates of 201-202 L/ha.

Details of soil used
Geographic location
Depth of soil collection
Soil texture
   %  sand
   %  silt
   %  clay
pH:

% organic carbon
CEC
Moisture at 1/3 atm (%)

N/A
N/A
Loamy fine sand
89
3
8
7.2 (in water)
6.7 (in 0.01 M CaCl2)
0.56%
Not reported
Not reported 
Soil was a mixture of kaolinite clay, industrial quartz sand and peat with crushed limestone added to buffer pH.
Organic matter 0.96%
A sample of soil representative of that used in this study was sent to Agvise Laboratories, Inc., in Northwood, ND, for analysis of the particle size distribution and organic matter content of the soil. The soil used for plant studies are periodically screened for pesticides and metals. No analytes were measured at levels that were expected to have an impact on the study. Although the complete reports were filed in the archives at EAG Laboratories the results of these analyses were not provided in the study report for reference.

Soil mixes containing sandy loam, loam, or clay loam soil with no greater than 2% organic matter are preferable. Glass beads, rock wool, and 100% acid washed sand are not preferred.
OECD prefers the soil to be sieved (0.5 cm) to remove coarse fragments. Carbon content should not exceed 1.5% (3% organic matter). Fine particles (under 20um) makeup should be between 10 and 20%. The recommended pH is between 5.0 and 7.5.
Details of nutrient medium, if used

N/A

Watering regime and schedules
Water source/type:

Volume applied:
Interval of application:
Method of application:

Laboratory well water purified by reverse osmosis (R/O).
Not specified.
As needed.
The plants were bottom watered every, one to three days, as needed.
The days on which watering occurred are listed in Appendix 5 (pgs. 63-64) of the study report.
The well water used for plant studies are periodically screened for pesticides and metals. No analytes were measured at levels that were expected to have an impact on the study. Although the reports were filed in the archives at EAG Laboratories the results of these analyses were not provided in the study report for reference.

EPA prefers that bottom watering be utilized for vegetative vigor studies so that the chemical is not leached out of the soil during the test.
Any pest control method/fertilization, if used
A slow release fertilizer was added to soil before planting.

Test conditions

Temperature:
Photoperiod:

Light intensity and quality:

Relative humidity:

Temperature:
Photoperiod:

Light intensity and quality:

Relative humidity:
Onion, sugarbeet, soybean, tomato and ryegrass:
Mean 23.09, range 16.06-35.34˚C
16L:8D 
Natural sunlight supplemented with artificial light.  
Mean 14.0, range 12.4-16.7 moles PAR

Mean 66.22, range 29.51-93.20%

Cabbage, oilseed rape, lettuce, wheat and corn: 
Mean 24.26, range 16.98-34.91˚C
16L:8D 
Natural sunlight supplemented with artificial light.  
Mean 14.0, range 10.8-17.0 moles PAR

Mean 62.63, range 28.36-91.50%
Environmental conditions are summarized in Appendix 5 (pgs. 63-64) of the study report.

EPA prefers that the cold vs warm loving plants be tested in two separate groups to optimize plant growth.

OECD prefers that the temperature, humidity and light conditions be suitable for maintaining normal growth of each species for the test period.
Reference chemical (if used)
Name:
Concentrations: 

N/A

Other parameters, if any
None

   2. Observations:  

Table 4:  Observation Parameters - Vegetative Vigor.
Parameters
Vegetative Vigor

Details
Remarks
Parameters measured (e.g., number of germinated seeds, emerged seedlings, plant height, dry weight or other endpoints)
- Survival
- Height
- Mean dry weight
- Phytotoxicity

Measurement technique for each parameter 
Phytotoxicity was visually determined. Height was measured to the apical meristem or the tip of the longest leaf.  Mean plant weight was estimated by cutting plant at soil surface and measuring the total dry weight per replicate divided by number of plants weighed following oven drying.  

Observation intervals 
Each pot was inspected weekly (days 7, 14, & 21) and phytotoxicity assessments performed.  Plant height and dry weight were recorded at study termination (day 21).

Other observations, if any
N/A

Were raw data included?
Yes

Phytotoxicity rating system, if used
0- No effect; 10-30- Slight effect; 40-60- Moderate effect; 70-90- Severe effect; 100 = death of entire plant.
Frans, Robert E. and Ronald E. Talbert. 1977. Design of Field Experiments and the Measurement and Analysis of Plant Responses, pp. 15-23, in B. Truelove, ed., Research Methods in Weed Science. Southern Weed Science Society, Auburn University, Alabama

II. RESULTS and DISCUSSION:

   A. INHIBITORY EFFECTS:

Vegetative Vigor:  

      Negative control survival was 100%. The study author found no significant inhibitions in survival in any species tested compared to the negative control. The reviewer did not find significant inhibitions in survival in any species tested (p>0.05). 

      The study author and reviewer did not find significant inhibitions in height in any species tested compared to the negative control (p>0.05). 
      
      The study author found significant inhibition in soybean dry weight, but not in any other species tested compared to the negative control. Significant inhibitions in soybean dry weight were 19 and 20% at the 5.2 and 10.5 lb ai/A treatment levels, respectively, compared to the negative control (Dunnett's test, p<0.05). The reviewer also found significant inhibitions in soybean dry weight of 19 and 20% at the 4.98 and the 10.2 lb a.i./A treatment levels, respectively, compared to the negative control (Dunnett's test, p<0.05).

      Based on the study author's results, the most sensitive monocot and dicot could not be determined due to lack of toxicity. The study author determined the NOER and LOER for soybean dry weight was 2.6 and 10.5 lb ai/A, respectively, but no treatment related reductions were greater than 25% for any endpoint or any species.
      
      Based on the phytotoxicity rating system used by the study author, there were none to slight effects in all species.  Soybean and sugarbeet phytotoxic effects included chlorosis, necrosis and leaf curl, and the effects were dose-related.
   
   B. REPORTED STATISTICS BY THE STUDY AUTHOR:  
      
   Plant shoot height, shoot dry weight and percent survival means were determined. Parametric assumptions for normal distribution and homogeneity of variance were tested. If appropriate, effects of treatment were evaluated with an ANOVA, and the treatment groups were compared to controls with a Dunnett's test. When assumptions were not met, statistical results were still accepted due to the robust nature of the Dunnett's test. A probability of less than 0.05 was considered statistically significant. Results of the Dunnett's test were used to help establish the NOER. Statistical analyses also included the determination of effect rates (ERX estimates) and their confidence limits, if necessary. ER25 and ER50 estimates were calculated when reductions in test endpoints among one or more treatment groups were at least 25% or 50%, respectively, relative to control means. Where reductions in treatment groups were less than 25% or 50% compared to the control, the ER25 or ER50 values were considered to be greater than the highest treatment group. All statistical computations were performed on a personal computer using SAS version 8. Nominal concentrations were used for all analyses.
   
Table 5: Effect of DCPA on 21-Day Vegetative Vigor
Species
Results summary for height (lb ai/A)

height (cm)
NOEC
ER05
95%CI
ER25
95%CI
ER50
95%CI
slope
95%CI
Cabbage
27-28.7
10.5
ND
N/A
>10.5
N/A
>10.5
N/A
N/A
N/A
Corn
88.4-94.6
10.5
ND
N/A
>10.5
N/A
>10.5
N/A
N/A
N/A
Lettuce
19.4-20.4
10.5
ND
N/A
>10.5
N/A
>10.5
N/A
N/A
N/A
Oilseed Rape
36-38.3
10.5
ND
N/A
>10.5
N/A
>10.5
N/A
N/A
N/A
Onion
28.7-31
10.5
ND
N/A
>10.5
N/A
>10.5
N/A
N/A
N/A
Ryegrass
30.5-33.3
10.5
ND
N/A
>10.5
N/A
>10.5
N/A
N/A
N/A
Soybean
64.1-72.2
10.5
ND
N/A
>10.5
N/A
>10.5
N/A
N/A
N/A
Sugarbeet
30.2-31.5
10.5
ND
N/A
>10.5
N/A
>10.5
N/A
N/A
N/A
Tomato
52.5-56.4
10.5
ND
N/A
>10.5
N/A
>10.5
N/A
N/A
N/A
Wheat
57.6-60
10.5
ND
N/A
>10.5
N/A
>10.5
N/A
N/A
N/A
ND- Not determined. NC- Not calculable.

Table 5a: Effect of DCPA on 21-Day Vegetative Vigor
Species
Results summary for biomass (lb ai/A)

weight (g)
NOEC
ER05
95%CI
ER25
95%CI
ER50
95%CI
slope
95%CI
Cabbage
4.56-5.17
10.5
ND
N/A
>10.5
N/A
>10.5
N/A
N/A
N/A
Corn
3.87-4.44
10.5
ND
N/A
>10.5
N/A
>10.5
N/A
N/A
N/A
Lettuce
4.37-5.02
10.5
ND
N/A
>10.5
N/A
>10.5
N/A
N/A
N/A
Oilseed Rape
4.56-5.01
10.5
ND
N/A
>10.5
N/A
>10.5
N/A
N/A
N/A
Onion
0.177-0.21
10.5
ND
N/A
>10.5
N/A
>10.5
N/A
N/A
N/A
Ryegrass
0.875-1.01
10.5
ND
N/A
>10.5
N/A
>10.5
N/A
N/A
N/A
Soybean1
3.89-5.06
2.6
ND
N/A
>10.5
N/A
>10.5
N/A
N/A
N/A
Sugarbeet
2.69-3.08
10.5
ND
N/A
>10.5
N/A
>10.5
N/A
N/A
N/A
Tomato
5.68-6.32
10.5
ND
N/A
>10.5
N/A
>10.5
N/A
N/A
N/A
Wheat
1.59-1.84
10.5
ND
N/A
>10.5
N/A
>10.5
N/A
N/A
N/A
ND- Not determined. NC- Not calculable.
1 Significant decrease in soybean dry weight, inhibition of 19 and 20% at the 5.2 and 10.5 lb ai/A treatment levels, respectively, compared to the negative control (Dunnett's test, p<0.05).

Table 5b:  Effect of DCPA on 21-Day Vegetative Vigor
Species
Results summary for survival (lb ai/A)

%
NOEC
ER05
95%CI
ER25
95%CI
ER50
95%CI
slope
95%CI
Cabbage
100
10.5
ND
N/A
>10.5
N/A
>10.5
N/A
N/A
N/A
Corn
100
10.5
ND
N/A
>10.5
N/A
>10.5
N/A
N/A
N/A
Lettuce
100
10.5
ND
N/A
>10.5
N/A
>10.5
N/A
N/A
N/A
Oilseed Rape
100
10.5
ND
N/A
>10.5
N/A
>10.5
N/A
N/A
N/A
Onion
100
10.5
ND
N/A
>10.5
N/A
>10.5
N/A
N/A
N/A
Ryegrass
97-100
10.5
ND
N/A
>10.5
N/A
>10.5
N/A
N/A
N/A
Soybean
97-100
10.5
ND
N/A
>10.5
N/A
>10.5
N/A
N/A
N/A
Sugarbeet
100
10.5
ND
N/A
>10.5
N/A
>10.5
N/A
N/A
N/A
Tomato
97-100
10.5
ND
N/A
>10.5
N/A
>10.5
N/A
N/A
N/A
Wheat
100
10.5
ND
N/A
>10.5
N/A
>10.5
N/A
N/A
N/A
ND- Not determined. NC- Not calculable.

Plant Injury Index*
Control
Cabbage
Corn
Lettuce
Oilseed Rape
Onion
Ryegrass
Soybean
Sugarbeet
Tomato 
Wheat
Formulation Blank
0-8
0-2
0-14
0-10
0-10
0-18
0-26
0-28
0-22
0-20
0-4
N/A
*0- No effect; 10-30- Slight effect; 40-60- Moderate effect; 70-90- Severe effect; 100 = death of entire plant.

   C. VERIFICATION OF STATISTICAL RESULTS BY THE REVIEWER: 

   All analyses were conducted comparing treated to the negative control. These analyses were conducted using CETIS version 1.8.7.12 and backend settings approved for use by EFED on 10/20/15.   Data for each endpoint were tested to determine if their distributions were normal and if their variances were homogeneous using Shapiro-Wilk's and Levene's tests, respectively. Data that satisfied these assumptions were subjected to Dunnett's and William's tests, and data that did not satisfy these assumptions were subjected to the non-parametric Mann-Whitney U and Jonckheere's tests. Linear (survival) and non-linear (height and dry weight) regression models were used to interpret EC/ICx values. Measured concentrations were used for all analyses.

Table 6:  Effect of DCPA on 21-Day Vegetative Vigor
Species
Results summary for height (lb ai/A)

height (cm)
NOEC
IC05
95%CI
IC25
95%CI
IC50
95%CI
slope
95%CI
Cabbage*
27-28.7
10.2
11.1
N/A-17.6
>10.2
N/A
>10.2
N/A
N/A
N/A
Corn
88.4-94.6
10.2
>10.2
N/A
>10.2
N/A
>10.2
N/A
N/A
N/A
Lettuce
19.4-20.4
10.2
>10.2
N/A
>10.2
N/A
>10.2
N/A
N/A
N/A
Oilseed Rape*
36-38.3
10.2
>10.2
N/A
>10.2
N/A
>10.2
N/A
N/A
N/A
Onion
28.7-31
10.2
8.98
N/A-30.6
>10.2
N/A
>10.2
N/A
N/A
N/A
Ryegrass
30.5-33.3
10.2
NC
N/A
>10.2
N/A
>10.2
N/A
N/A
N/A
Soybean
64.1-72.2
10.2
NC
N/A
>10.2
N/A
>10.2
N/A
N/A
N/A
Sugarbeet
30.2-31.5
10.2
>10.2
N/A
>10.2
N/A
>10.2
N/A
N/A
N/A
Tomato
52.5-56.4
10.2
>10.2
N/A
>10.2
N/A
>10.2
N/A
N/A
N/A
Wheat**
57.6-60
10.2
30.2
6720-0.26
0.109
30.3-0.000166
0.0000199
28.4-N/A
N/A
N/A
ND- Not determined. NC- Not calculable.
*Endpoint and/or confidence limits are outside the tested range of concentrations and should be interpreted with caution.
**Wheat height showed an inverse dose response.

Table 6a: Effect of DCPA on 21-Day Vegetative Vigor
Species
Results summary for biomass (lb ai/A)

weight (g)
NOEC
IC05
95%CI
IC25
95%CI
IC50
95%CI
slope
95%CI
Cabbage
4.56-5.17
10.2
>10.2
N/A
>10.2
N/A
>10.2
N/A
N/A
N/A
Corn
3.87-4.44
10.2
>10.2
N/A
>10.2
N/A
>10.2
N/A
N/A
N/A
Lettuce
4.37-5.02
10.2
>10.2
N/A
>10.2
N/A
>10.2
N/A
N/A
N/A
Oilseed Rape
4.56-5.01
10.2
>10.2
N/A
>10.2
N/A
>10.2
N/A
N/A
N/A
Onion
0.177-0.21
10.2
NC
N/A
>10.2
N/A
>10.2
N/A
N/A
N/A
Ryegrass*
0.875-1.01
10.2
ND
N/A
ND
N/A
ND
N/A
N/A
N/A
Soybean1*
3.89-5.06
2.52
2.72
N/A-5.56
11.9
5.96-20.1
>10.2
N/A
N/A
N/A
Sugarbeet*
2.69-3.08
10.2
ND
N/A
>10.2
N/A
>10.2
N/A
N/A
N/A
Tomato
5.68-6.32
10.2
>10.2
N/A
>10.2
N/A
>10.2
N/A
N/A
N/A
Wheat
1.59-1.84
10.2
>10.2
N/A
>10.2
N/A
>10.2
N/A
N/A
N/A
ND- Not determined. NC- Not calculable.
*Endpoint and/or confidence limits are outside the tested range of concentrations and should be interpreted with caution.
1 Significant decrease in soybean dry weight, inhibition of 19 and 20% at the 4.98 and the 10.2 lb ai/A treatment levels, respectively, compared to the negative control (Dunnett's test, p<0.05).
Table 6b:  Effect of DCPA on 21-Day Vegetative Vigor
Species
Results summary for survival (lb ai/A)

%
NOEC
EC05
95%CI
EC25
95%CI
EC50
95%CI
slope
95%CI
Cabbage
100
10.2
>10.2
N/A
>10.2
N/A
>10.2
N/A
N/A
N/A
Corn
100
10.2
>10.2
N/A
>10.2
N/A
>10.2
N/A
N/A
N/A
Lettuce
100
10.2
>10.2
N/A
>10.2
N/A
>10.2
N/A
N/A
N/A
Oilseed Rape
100
10.2
>10.2
N/A
>10.2
N/A
>10.2
N/A
N/A
N/A
Onion
100
10.2
>10.2
N/A
>10.2
N/A
>10.2
N/A
N/A
N/A
Ryegrass
97-100
10.2
>10.2
N/A
>10.2
N/A
>10.2
N/A
N/A
N/A
Soybean
97-100
10.2
>10.2
N/A
>10.2
N/A
>10.2
N/A
N/A
N/A
Sugarbeet
100
10.2
>10.2
N/A
>10.2
N/A
>10.2
N/A
N/A
N/A
Tomato
97-100
10.2
>10.2
N/A
>10.2
N/A
>10.2
N/A
N/A
N/A
Wheat
100
10.2
>10.2
N/A
>10.2
N/A
>10.2
N/A
N/A
N/A
ND- Not determined. NC- Not calculable.

Plant Injury Index*
Control
Cabbage
Corn
Lettuce
Oilseed Rape
Onion
Ryegrass
Soybean
Sugarbeet
Tomato 
Wheat
Formulation Blank
0-8
0-2
0-14
0-10
0-10
0-18
0-26
0-28
0-22
0-20
0-4
N/A
*0- No effect; 10-30- Slight effect; 40-60- Moderate effect; 70-90- Severe effect; 100 = death of entire plant.
   Most sensitive monocot:Could not be determined due to lack of toxicity
   
   EC50/IC50: >10.2 lb a.i./A95% C.I.: N/A
   EC25/IC25: >10.2 lb a.i./A95% C.I.: N/A
   EC05/IC05: N/A95% C.I.: N/A
   NOAEC: 10.2 lb a.i./A
   Slope: N/A95% C.I.: N/A
   
   Most sensitive dicot:   Soybean, based on dry weight*
   
   EC50/IC50: >10.2 lb a.i./A95% C.I.: N/A
   EC25/IC25: 11.9 lb a.i./A95% C.I.: 5.96-20.1 lb a.i./A
   EC05/IC05: 2.72 lb a.i./A95% C.I.: N/A-5.56 lb a.i./A
   NOAEC: 2.52 lb a.i./A
   LOAEC: 4.98 lb a.i./A
   Slope: N/A95% C.I.: N/A
   *Some endpoints and/or confidence intervals are outside the range of concentrations and should be interpreted with caution.
   
   D.  STUDY DEFICIENCIES:   
   
The physico-chemical properties of the test material were not reported. This is a minor deficiency.
Soil CEC and % moisture were not reported. This is a minor deficiency.
A range-finding study was conducted, but only the summary results were reported in Appendix 16 of the study report, and some details were not provided in the data summary tables that were provided in the Appendix.

   E.  REVIEWER'S COMMENTS:  
   
      The reviewer and study author results were in agreement for monocots, but not for dicots. Both the study author and reviewer's most sensitive monocot could not be determined due to lack of toxicity. Significant inhibitions in this study did not approach 25% for any monocot species. Therefore, the IC25 was visually estimated as >10.2 lb a.i./A, the highest tested application rate, and the NOAEC was 10.2 lb a.i./A. Based on the study author's results, the most sensitive dicot could not be determined due to lack of toxicity. The study author determined the NOER and LOER for soybean dry weight was 2.6 and 10.5 lb a.i./A, respectively, but concluded the reductions were not treatment related and significant inhibitions did not approach 25% for any endpoint and any species. The reviewer found the most sensitive dicot was soybean, based on dry weight, with NOAEC and IC25 values of 2.52 and 11.9 lb a.i./A, respectively; however, the IC25 value and confidence intervals were outside the tested range of concentrations and should be interpreted with caution. The reviewer's results are presented in the Executive Summary and Conclusions sections of this DER.
      
      The in-life portion of this study was initiated on September 5, 2013 and completed on September 26, 2013 for onion, sugarbeet, soybean, ryegrass, and tomato; and initiated on September 6, 2013 and completed on September 27, 2013 for cabbage, oilseed rape, lettuce, wheat, and corn. Dry weight measurements were completed on September 30, 2013. 
      
   F.  CONCLUSIONS:   
   
      This study is scientifically sound and is classified as acceptable. The most sensitive monocot species could not be determined due to lack of toxicity. Therefore, the IC25 was visually estimated as >10.2 lb a.i./A, the highest tested application rate, and the NOAEC was 10.2 lb a.i./A for all tested monocot species. The most sensitive dicot was soybean, based on dry weight, with NOAEC and extrapolated IC25 values of 2.52, and 11.9 lb a.i./A, respectively (with 20% effects at the 10.2 lb a.i./A, highest test level); however, the IC25 value and confidence intervals were outside the tested range of concentrations and should be interpreted with caution. 
      
Most sensitive monocot and EC25/IC25: None; the IC25 was visually estimated as >10.2 lb a.i./A, the highest tested application rate for all tested monocot species.
Most sensitive dicot and EC25/IC25:  Soybean (based on dry weight, 11.9 lb a.i./A; extrapolated, with 20% effects at the 10.2 lb a.i./A, highest test level)

III.  REFERENCES:  

U.S. Environmental Protection Agency. 2012. Series 850- Ecological Effects Test Guidelines, OCSPP Number 850.4150: Vegetative Vigor. 

Frans, Robert E. and Ronald E. Talbert. 1977. Design of Field Experiments and the Measurement and Analysis of Plant Responses. Pages 15-23 in B. Truelove, ed. Research Methods in Weed Science. Southern Weed Science Society, Auburn University, Alabama. 

SAS Institute, Inc. 1999. SAS Proprietary Software Version 8, Gary, NC, SAS Institute, Inc.

APPENDIX 1. APPLICATION RATE CONVERSIONS from EXCEL FILE