REGISTRATION REVIEW

ECOLOGICAL RISK ASSESSMENT AND EFFECTS 

DETERMINATION

Trinexapac-Ethyl

CAS Number 95266-40-3

USEPA PC CODE 112602

ethyl (RS)-4-cyclopropyl(hydroxyl)methylene-3,5-

dioxocyclohexanecarboxylate

Prepared by:

Meghan Radtke, Ph.D., Biologist

Christopher Koper, M.S., Chemist

Environmental Risk Branch I

Reviewed by:

Michael Lowitt, Ph.D., Biologist

Faruque Khan, Ph.D., Senior Scientist

Environmental Risk Branch I

Environmental Fate and Effects Division

U. S. Environmental Protection Agency

Office of Pesticide Programs

Environmental Fate and Effects Division

Environmental Risk Branch I

1200 Pennsylvania Ave., NW

Mail Code 7507P

Washington, DC 20460
ii

Executive Summary

E.1 Nature of Stressor

Trinexapac-ethyl is a growth regulator/herbicide in the cyclohexane carboxylic acid class of 

chemicals. It is currently registered for the management of turf growth in warm and cool 

season grasses, lodging prevention in cereals and grasses grown for seed, and internode 

shortening and harvest extension in sugarcane. Trinexapac-ethyl reduces the growth of 

numerous types of turf grasses including bahiagrass, bermuda grass, bluegrass, red and tall 

fescue, and annual and perennial ryegrass for up to 8 weeks. It is taken up through the 

foliage and inhibits the biosynthesis of gibberellin – a plant growth hormone. The free acid 

of trinexapac-ethyl inhibits the hydroxylation of gibberellin20 to gibberellin1 by competitively 

inhibiting the regulatory enzyme 3-hydroxylase, leading to a reduction in the size of leaves 

and stems.

E.2 Assessment of Risk

E.2.1 Physico-Chemical and Environmental Fate Properties

Based on the results of a laboratory soil volatility study, trinexapac-ethyl appears not to 

volatilize. This is supported by its low vapor pressure (1.62 x 10-5 mm Hg at 25oC) (MRID 

41604203) and Henry’s Law (5.27 x 10-10 atm-m3

/mol). 

Biodegradation is the major dissipation pathway for trinexapac-ethyl, specifically aerobic 

biotransformation in terrestrial environments and aerobic and anaerobic biotransformation in 

aquatic environments. Half-lives ranged from 2.8 hours in a loam soil to 4.3 days in a loamy 

sand soil in an aerobic soil metabolism study (MRID 46809303). Half-lives ranged from 2.8 

days in a river water-sand sediment system to 4.0 days in a pond water-sandy clay loam 

sediment system in an aerobic aquatic metabolism study (MRID 46809304). Total system 

half-lives averaged 3.5 days in a pond water-sandy clay loam sediment system and 3.5 days 

in a lake water-loamy sand sediment system in an anaerobic aquatic metabolism study 

(MRID 48043712). Biodegradation was slower under anaerobic soil conditions. The 

estimated half-life is about 25 days in a sandy loam soil (MRID 41563933).

Trinexapac-ethyl is stable to hydrolysis in acidic and neutral conditions and hydrolyzes under 

basic conditions (t1⁄2 = 8.1 days; MRID 41563930). Photodegradation does not appear to be a 

major degradation pathway in aqueous and soil environments. The aqueous photolysis study 

shows an environmental phototransformation half-life of about 18 days (MRID 46809302). 

The compound was considered stable in the soil photolysis study since the extrapolated halflife was well beyond the duration of the study (MRID 42081406). 

The major environmental degradates of trinexapac-ethyl include its free acid CGA-179500, 

CGA-313458, an open chain cyclohexane ring, CO2 and an unidentified hydroproduct M3. 

Trinexapac acid’s (CGA-179500) maximum formation percentages of applied radioactivity

occurred during hydrolysis at 91%, soil photolysis (52%), aerobic soil metabolism (44%), 

aerobic aquatic metabolism (71%) and anaerobic aquatic metabolism (88%). CGA-313458 

maximum formation was 22% occurring in a hydrolysis study. The unidentified 

hydroproduct M3 maximum formation was 35% occurring during a hydrolysis study. The 
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open chain cyclohexane ring maximum formation was 12% occurring during a soil 

photolysis study. In addition, significant CO2 formation (mineralization) occurred during the 

aqueous photolysis (20%), aerobic soil metabolism (71%), aerobic aquatic metabolism 

(73%), and aerobic aquatic metabolism (85%) studies. Structures and MRID references can 

be found in Appendix C. 

The parent ester (including its free acid CGA-179500), CGA-313458, an open chain 

cyclohexane ring, and an unidentified hydroproduct – M3 –) was included in a Total Toxic 

Residue (TTR) approach as an upper bound estimate of risk (i.e., it was assumed that the 

degradates have similar toxicity as their parent – trinexapac-ethyl) (Tables 4 and 5).

Based on the batch equilibrium data, adsorption of trinexapac-ethyl (Koc = 60 to 635 ml/goc; 

MRID 41563936 and 41663937) is characterized as being mobile to moderately mobile in 

the test soils1 (FAO Classification). In addition, adsorption data for trinexapac acid (Koc = 

144 to 609 mL/goc) is characterized as being moderately mobile in test soils. Terrestrial field 

dissipation data indicated that under typical use, the vast majority of the compound and its 

major metabolite, trinexapac acid, dissipate in the grass and thatch and sod layer by study 

termination. Following the final application, dissipation half-lives were less than 3 days for 

trinexapac-ethyl and ranged from 5.1 to 36.5 days for trinexapac-acid (MRID 48043710, 

48043711). It is important to note that this 36.5 day (dissipation) half-life for the acid is 

longer than the 5.2 day 90th percentile TTR (degradation) half-life modeled as the aerobic 

soil input parameter in this assessment. This may be from differences between laboratory 

(degradation) studies and field (dissipation) studies.

For trinexapac-ethyl, the range of bioconcentration factors (BCFs) for edible tissue, nonedible tissue, and whole fish (from 2.5 to 11) indicate a low potential for bioconcentration in 

fish (MRID 41604207).

E.2.2 Ecological Risk Conclusions

The specific taxa that may be at risk from trinexapac-ethyl are dependent on the specific 

registered use. In general, registered uses of trinexapac-ethyl may affect and are likely to 

directly adversely affect birds, reptiles, and land-phase amphibians (acute and chronic), 

terrestrial invertebrates, and terrestrial plants. There were no risks identified for the cereals 

uses; however, direct effects were identified for the sugarcane, grasses grown for seed, and 

turf uses. Direct effects are not expected for other taxonomic groups. 

Given that there are possible direct effects to birds, reptiles, and land-phase amphibians, 

terrestrial invertebrates, and plants, indirect effects to other organisms could occur. Indirect 

effects could include changes to food, shelter, seed dispersal/pollination, or other alterations 

of habitat. 

 1 USEPA. 2006. Standardized Soil Mobility Classification Guidance. U.S. Environmental Protection Agency, Office of 

Prevention, Pesticides and Toxic Substances, Office of Pesticide Programs, Environmental Fate and Effects Division, 

Memorandum. April 21, 2006.
iv

A spray drift analysis indicated that risks to terrestrial invertebrates and birds, reptiles, and 

land-phase amphibians from ground and aerial applications of trinexapac-ethyl could be 

eliminated through the implementation of buffers (3 to 20 ft) around their habitat for the 

sugarcane and grasses grown for seed uses. Protective buffers for the turf use range from 7 

to 20 ft. The risk to plants is primarily driven by runoff, hence spray drift buffers were not 

calculated for terrestrial plants. Generally speaking, plants farther from the use site will be 

exposed to less pesticide than those closer, thus buffers may be a useful mitigation option for 

plants affected by runoff.

Tables E.1 – E.2 list the potential direct and indirect effects to listed and non-listed species, 

based on risk quotients exceeding the level of concern, as well as the organism group and 

size classes potentially at risk from the highest application rate for each use of trinexapacethyl.

Table E.1. Potential direct effects to listed and non-listed terrestrial organisms from 

exposure to trinexapac-ethyl1

TrinexapacethylListed Terrestrial Species Non-Listed Terrestrial Species

Birds2 Mammals Terr. 

inverts

Plants Birds2 Mammals Terr.

inverts

Plants

Acute Chronic Acute Chronic Acute Chronic Acute Chronic

Cereals (oat, 

wheat, barley, 

triticale)

N N N N N N N N N N N N

Sugarcane Y

(S)

N N N Y Y N N N N N N

Grasses 

grown for 

seed

Y

(S)

N N N Y Y N N N N N Y

Turf (0.34 lb 

ai/A)

Y

(S, M)

N N N Y Y N N N N N N

Turf (0.68 lb 

ai/A)

Y

(S, M)

Y N N Y Y N Y N N N Y

Turf (1.36 lb 

ai/A)

Y

(S, M)

Y N N Y Y Y

(S)

Y N N N Y

Turf (0.35 lb 

ai/A) granular

Y

(S)

NC N N NC NC N NC N N NC NC

Turf (0.44 lb 

ai/A) granular

Y

(S)

NC N N NC NC N NC N N NC NC

Turf (0.88 lb 

ai/A) granular

Y

(S)

NC N N NC NC Y

(S)

NC N N NC NC
v

1 Y= Potential direct effects (RQ ≥ LOC); N = Potential direct effects not expected (RQ < LOC); S, M or L 

indicate which size class is potentially affected; S = small bird (20 g) or mammal (15 g); M = medium bird (100 

g) or mammal (35 g); L = large bird (1000 g) or mammal (1000 g). For mammals, chronic size classes are for 

dose-based exposure only. Dietary-based acute and chronic exposure for birds and mammals is not evaluated 

using body weights. RQ values were determined for these specific weights only, therefore, it is expected that 

potential direct effects may exist between two size classes in which the lower size class exceeded the LOC but 

the next size class did not. Therefore, for example, if small birds (20 g) exceeded the LOC but medium birds 

(100 g) did not, then potential direct effects may exist for all birds less than 100 g at any life stage until can be 

shown otherwise.

2 Birds are surrogates for terrestrial reptiles and terrestrial-phase amphibians.

NC = RQs on an LD50/ft2 basis were only calculated for birds and mammals for the granular applications 

because the exposure pathway is via consumption of individual granules.

Table E.2. Potential direct effects to listed and non-listed aquatic organisms from 

exposure to trinexapac-ethyl1

Trinexapac-ethyl Listed and Non-Listed Species

Freshwater Fish Estuarine/Marine 

Fish

Vascular 

Aquatic 

Plants

Freshwater 

Invertebrates

Estuarine/Marine 

Invertebrates

Acute Chronic Acute Chronic Acute Chronic Acute Chronic

Cereals (oat, wheat, 

barley, triticale)

N N N N N N N N N

Sugarcane N N N N N N N N N

Grasses grown for seed N N N N N N N N N

Turf (0.34 lb ai/A) N N N N N N N N N

Turf (0.68 lb ai/A) N N N N N N N N N

Turf (1.36 lb ai/A) N N N N N N N N N 1 Y= Potential direct effects; N = Potential direct effects not expected

E.3 Uncertainties

Some data and other supporting information were not available to the Agency as it conducted 

the preliminary risk assessment for trinexapac-ethyl. As such, certain assumptions were 

made and conclusions were based on the information that was available. For some taxa, this 

may have resulted in the use of overly conservative approaches for evaluating risk. EFED 

has identified information it believes may help best resolve these uncertainties. Additional 

information may allow EFED to refine its risk conclusions for certain species. Below is a 

summary of the uncertainties associated with the risk assessment of trinexapac-ethyl.

E.3.1 Ecotoxicity Data Gaps and Uncertainties

There were several ecotoxicity endpoints for which data were not available. 

• Estuarine/Marine Invertebrate (Chronic) OPPTS 850.1350. Data were not available 

for chronic effects to estuarine/marine invertebrates. In the absence of data, an acuteto-chronic ratio will be used in the registration review risk assessment.

• Estuarine/Marine Fish (Chronic) OPPTS 850.1400. Chronic data are not available for 

the sheepshead minnow. A comparison of acute endpoints shows that freshwater fish 

are more sensitive to trinexapac-ethyl than estuarine/marine fish. Therefore, the 

freshwater fish chronic toxicity value will be used as a protective surrogate for the 

estuarine/marine chronic toxicity value. 
vi

• Honeybee Oral Toxicity (Acute) OECD 213. Acute oral toxicity data are not 

available for the honeybee. As outlined in the Pollinator White Paper, this study is 

necessary to conduct a complete risk assessment on honeybees, which currently act as 

surrogates for terrestrial invertebrates. In the absence of these data, the results from 

the acute contact toxicity analysis were extrapolated to acute oral toxicity.

• Honeybee Larvae Toxicity Non-Guideline. Larval toxicity information is not 

available for the honeybee. As outlined in the Pollinator White Paper, this study is 

necessary to conduct a complete risk assessment on honeybees, which currently act as 

surrogates for terrestrial invertebrates. In the absence of these data, risk was assumed 

for terrestrial invertebrate larvae, based on the results of the acute contact toxicity 

analysis. 

E.3.2 Mixture Toxicity

There are several trinexapac-ethyl products that contain paclobutrazol and/or flurprimidol as 

active ingredients. Both of these are also plant growth regulators and it is uncertain if there 

could be additional adverse effects on terrestrial plants from their use.

E.3.3 Fate Data Gaps

Currently, there are no outstanding data requirements for trinexapac ethyl. However, aside 

from a hydrolysis and an adsorption/desorption study for trinexapac acid (CGA-179500) 

there are no data available for the degradates of concern. A total toxic residue (TTR)

approach was employed for this assessment, including parent and major environmental 

degradates (CGA-179500, CGA-313458, the open chain cyclohexane ring, and the 

unidentified hydroproduct M3). This approach is expected to provide protective exposure 

estimation for aquatic organisms exposed to the major degradates of trinexapac-ethyl. It 

assumes that the degradates have equivalent fate and ecotoxicity properties as the parent – a 

conservative assumption.

E.3.4 Incomplete Life Histories of Listed Species

Currently, an incomplete database of life histories for each of the listed animals and plants is 

available for use by EFED. These life histories would include information such as body size 

at each life stage, food sources, relationships with other taxa, habitat, and reproductive habits. 

As such, conservative (protective) assumptions were made concerning the potential 

relationships between species in that each species was assumed to have a relationship with 

the other taxa. This is assumed to be an overestimation of the actual species that have a 

species dependant relationship. 

E.3.5 Locations of Listed Species

The specific occurrences of listed species are not known in most cases beyond the countylevel. If the location of a species was not known in greater detail than the county level, the 

species was assumed to occur anywhere within that county at any time. Likewise, crop 

location data are also uncertain. Crops may rotate every year and some spatial datasets 

combine several crop types, making it impossible to distinguish one crop from another. Data 

layers for turf are not available and could not be incorporated into the assessment. Further, 

timing may play a role in the location of species and whether it overlaps with the time that a 

particular crop is in a field. These assumptions may lead to an overestimation of co-
vii

occurrence with trinexapac-ethyl exposure and overestimation of the number of species 

potentially at risk.
viii

Table of Contents

Introduction............................................................................................................................. 12

Purpose of Assessment........................................................................................................ 12

Problem Formulation........................................................................................................... 13

Previous Risk Assessments ............................................................................................. 14

Stressor Source and Distribution ..................................................................................... 14

Mechanism of Action.............................................................................................................. 14

Overview of Pesticide Use and Usage .................................................................................... 14

Environmental Fate and Transport .................................................................................. 18

Summary of Environmental Fate ............................................................................................ 18

Receptors......................................................................................................................... 20

Effects to Organisms............................................................................................................... 20

Incident Database Review....................................................................................................... 21

Data Gaps Identified ............................................................................................................... 21

Ecosystems Potentially at Risk ............................................................................................... 22

Conceptual Model............................................................................................................ 22

Risk Hypothesis............................................................................................................... 23

Analysis Plan ................................................................................................................... 24

Measures to Evaluate the Risk Hypothesis and Conceptual Model ....................................... 24

Measures of Effect .................................................................................................................. 24

Integration of Exposure and Effects ....................................................................................... 25

Analysis of Co-occurance of Federally Listed Species with Trinexapac-ethyl...................... 25

Exposure Assessment.............................................................................................................. 27

Aquatic Exposure Assessment ............................................................................................ 27

Monitoring Data .................................................................................................................. 27

Aquatic Exposure Modeling................................................................................................ 27

TIER II PRZM/EXAMS Model.............................................................................................. 28

Aquatic Exposure Modeling Results................................................................................... 33

Dietary-Based Trinexapac-Ethyl Residue Levels............................................................ 35

Off-Field Terrestrial and Wetland/Riparian Plant Trinexapac-Ethyl Exposure.............. 40

Effects Characterization.......................................................................................................... 43

Terrestrial Vertebrate Toxicology....................................................................................... 43

Effects on Birds............................................................................................................... 43

Effects on Mammals........................................................................................................ 44

Terrestrial Invertebrate Toxicology .................................................................................... 45

Aquatic Vertebrate (Fish) Toxicology ................................................................................ 46

Effects to Freshwater Fish and Aquatic-Phase Amphibians ........................................... 46

Effects to Estuarine-Marine Fish..................................................................................... 46

Aquatic Invertebrate Toxicology ........................................................................................ 48

Effects to Freshwater Invertebrates................................................................................. 48

Effects to Estuarine-Marine Invertebrates....................................................................... 48

Terrestrial Plant Toxicology................................................................................................ 50

Aquatic Plant Toxicology.................................................................................................... 51

Results: Risk Characterization................................................................................................ 53

Risk Estimation ................................................................................................................... 53

Direct Effects to Non-Target Terrestrial Vertebrates...................................................... 53
ix

Direct Effects to Birds, Reptiles, and (land-phase) Amphibians..................................... 53

Direct Effects to Mammals............................................................................................ 576

Direct Effects to Non-Target Terrestrial Invertebrates.................................................... 57

Direct Effects to Terrestrial and Wetland/Riparian Plants.............................................. 57

Direct Effects to Freshwater Fish (Amphibians), Invertebrates and Estuarine-Marine 

Fish (Amphibians) and Invertebrates, and Aquatic Plants.............................................. 59

Probit Slope Response Analysis of LOC Values and Acute RQ Values......................... 66

Risk Description.................................................................................................................. 67

Direct Effects to Terrestrial Birds, Reptiles, and Amphibians ............................................... 67

Direct Effects to Terrestrial Mammals ................................................................................... 70

Direct Effects to Terrestrial Invertebrates............................................................................... 71

Direct Effects to Terrestrial Plants.......................................................................................... 72

Direct Effects to Aquatic Fish, Invertebrates, and Plants....................................................... 74

Listed Species Effects Analysis....................................................................................... 76

Action Area............................................................................................................................. 81

Effects Area Determination .................................................................................................... 81

Uncertainties........................................................................................................................... 85

Effects and Risk Assessment Uncertainties ........................................................................ 85

Ecotoxicity Data Gaps..................................................................................................... 85

Mixture Toxicity....................................................................................85

Fate Data Gaps................................................................................................................. 85

Incomplete Life Histories of Listed Species.................................................................... 86

Locations of Listed Species............................................................................................. 86

Other Routes of Exposure................................................................................................ 86

Foliar Dissipation Half-life.............................................................................................. 86

Species Sensitivity........................................................................................................... 87

Endocrine Disruptor Screening Program (EDSP) ........................................................... 87

Spatial Analysis............................................................................................................... 87

References............................................................................................................................... 89

Appendix A – Bibliography of MRIDs .................................................................................. 95

Appendix B – Total Toxic Residue (TTR) Calculations........................................................ 95

Appendix C – Trinexapac-Ethyl and Its Major and Minor Degradates................................ 106

Appendix D – ECOTOX Literature Search .......................................................................... 109

Appendix E – SIP and STIR Model Output.......................................................................... 135

Appendix F – Risk Quotient Method and Levels of Concern .............................................. 138

Appendix G – Surface Water Model Results and Sample Input and Outputs...................... 140

Appendix H – TerrPlant Output............................................................................................ 141

Appendix I – T-REX Output................................................................................................. 143

Appendix J – Listed Species Analysis.................................................................................. 143
x

List of Abbreviated Terms and Symbols

@ symbol for “at”

% symbol for “percent”

> symbol for “greater than”

< symbol for “less than”

μg/L symbol for “micrograms per liter”

oC symbol for “degrees Celsius”

ai active ingredient

Acc# accession number

BEAD Biological and Economical Analysis Division

bw body weight

CI confidence interval

CL confidence limit

DP# data package

EC emulsifiable concentrate

EC25 25% effect concentration

EC50 50% (or median) effect concentration

ECOTOX EPA managed database

EEC estimated environmental concentration

EFED Environmental Fate and Effects Division

e.g. Latin exempli gratia (“for example”)

et al. Latin et alii (“and others”)

etc. Latin et cetera (“and the rest” or “and so forth”)

FESTF FIFRA Endangered Species Task Force

FIFRA Federal Insecticide Fungicide and Rodenticide Act

FQPA Food Quality Protection Act

ft feet

g gram

GENEEC Generic Estimated Exposure Concentration model

IC50 50% (or median) inhibition concentration

i.e. Latin for id est (“that is”)

IMS information management system

Kg kilogram(s)

Km kilometer(s)

Koc symbol for the organic carbon partitioning coefficient

LAA likely to adversely affect

Lbs pounds

lb ai/A pound(s) of active ingredient per acre

LC50 50% (or median) lethal concentration

LD50 50% (or median) lethal dose

LOAEC lowest observable adverse effect concentration

LOAEL lowest observable adverse effect level

LOC level of concern

LOD level of detection

LOEC lowest observable effect concentration

Kow symbol for the octanol water partitioning coefficient
xi

LOQ level of quantitation

LUIS label use information system

m meter(s)

MA may affect

mg milligram(s)

mg/kg milligrams per kilogram (equivalent to ppm, except in the 

case of discussing dose such as mg/kg-bw)

mg/L milligrams per liter (equivalent to ppm)

mi mile(s)

MM may modify primary constituent element

MM/NSF may modify primary constituent element/no shapefile

mmHg millimeter of mercury

MRID master record identification number

MW molecular weight

NASS National Agricultural Statistics Service

NAWQA National Water Quality Assessment

NE no effect

NLAA not likely to adversely affect

NMFS National Marine Fisheries Service

NOAA National Oceanic and Atmospheric Administration

NOAEC no observable adverse effect concentration

NOAEL no observable adverse effect level

NOEC no observable effect concentration

OCSPP Office of Chemical Safety and Pollution Prevention

OPP Office of Pesticide Programs

OPPTS Office of Prevention, Pesticides and Toxic Substances

pH symbol for the negative logarithm of the hydrogen ion 

activity in an aqueous solution, dimensionless

pKa symbol for the negative logarithm of the acid dissociation 

constant, dimensionless

ppb parts per billion (equivalent to μg/L or μg/kg)

ppm parts per million (equivalent to mg/L or mg/kg)

SLUA screening level usage analysis

USDA United States Department of Agriculture

USEPA United States Environmental Protection Agency

USFWS United States Fish and Wildlife Service

USGS United States Geological Survey

Wt weight
12

Introduction

Purpose of Assessment

The purpose of this assessment is to evaluate the potential risks of trinexapac-ethyl’s 

registered uses on federally listed endangered and threatened (“listed”) species and all other 

non-target plant and animal (“non-listed”) species. This risk assessment incorporates the 

available effects data, modeling, and risk methodologies, some of which may not have been 

available at the time when previous trinexapac-ethyl registration actions occurred. Risks 

from direct and indirect effects are derived and evaluated in accordance with the risk 

assessment methodology described in the Agency’s Overview Document (USEPA, 2004). 

These risk findings are then used as part of an “effects determination” for listed species. The 

Agency will reach one of the following three conclusions regarding the potential for the 

registered trinexapac-ethyl use on food crops and turf to affect federally listed species:

• “No effect”

• “May affect, but not likely to adversely affect”

• “May affect, and likely to adversely affect”

If the results of the risk assessment show no indirect effects and the levels of concern (LOC) 

are not exceeded for direct effects for a given listed species taxonomic grouping (e.g., 

freshwater fish, small herbivorous mammal), a “no effect” determination is made, based on 

trinexapac-ethyl’s use within the action area for a “species” within the given taxonomic 

group. If, however, there is a potential for indirect effects and/or exposure exceeds the listed

species LOC values for direct effects for a given group, the Agency concludes a preliminary 

“may affect species” within the taxonomic group. The Agency then considers additional 

lines of evidence such as the geographical nature of the exposure, as well as more in-depth 

evaluations of the toxicological and ecological requirements to determine a rationale for a 

“not likely to adversely affect” or “likely to adversely affect” determination.

Similarly, the Agency will reach one of the following conclusions regarding the potential for 

trinexapac-ethyl uses to result in destruction or adverse modification of critical habitat:

• “No effect”

• “May Modify Primary Constituent Elements”

The Agency uses the risk assessment analysis for direct effects to categories of biological 

resource requirements to draw conclusions about effects to principle constituent elements of 

critical habitat. The Agency is limited in a practical sense to those principle constituent 

elements of critical habitat that are of a biological nature. If the results of the risk assessment 

show that no LOC is exceeded for all taxonomic groups a “no effect” determination for 

habitat modification is made. If an LOC is exceeded for one or more taxonomic groupings 

the Agency then considers additional lines of evidence such as direct effects to the species, 

the type and degree of effect on the taxonomic groupings, expected resultant effects on 

biologically mediated environmental processes (e.g., increased sedimentation from loss of 

vegetation) as compared to baseline environmental conditions, co-occurrence of the action 
13

area with critical habitat, the type of principle constituent elements associated with critical 

habitat for listed species in a taxonomic grouping to determine a rationale for a “may modify 

primary constituent elements.”

Problem Formulation

The problem formulation for this assessment and effects determination was provided in the 

USEPA Registration Review – EFED Problem Formulation for Trinexapac-Ethyl 

Registration Review May 20, 2008 document (D351403). Data were requested for two 

studies; classifications after EFED evaluation are listed in parentheses:

• 835.6100 – Terrestrial field dissipation (“supplemental” classification)

• 850.2100 – Avian acute oral study with a passerine species (“acceptable” 

classification)

All submitted studies for trinexapac-ethyl are listed in the MRID bibliography in Appendix 

A.

There were two modifications to the risk assessment process originally proposed in the 

problem formulation.

• Registrations for wheat, oats, barley, and sugarcane were added to the trinexapacethyl. In addition, the grasses grown for seed local registrations were expanded to the 

national level. These were added to the uses assessed in this risk assessment. 

• A Total Toxic Residue (TTR) approach was adopted for the parent ester, including its 

free acid CGA-179500, CGA-313458, an open chain cyclohexane ring, and an 

unidentified hydroproduct – M3 – based on recommendations from the Residues of 

Concern Knowledgebase Subcommittee (ROCKS) of EPA’s Health Effects Division 

(HED) (D390121). This decision document was based on EFED’s ROCKS 

memorandum (D389767) submitted to HED for review. Given that toxicity data

(EPA holdings) were not available for the degradates and ECOSAR was not a reliable 

predictor of endpoints for the parent, the TTR approach was adopted to provide a 

high end estimate of the risks to aquatic organisms. A more refined approach could 

then be adopted if aquatic risks were identified.

Under the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA), all pesticides 

distributed or sold in the United States generally must be registered by the United States 

Environmental Protection Agency (USEPA). To determine whether a pesticide can be 

registered, the USEPA evaluates its safety to non-target species based on a wide range of 

environmental and health effects studies. In 1996, FIFRA was amended by the Food Quality 

Protection Act (FQPA), and EPA was mandated to implement a new program for the 

periodic review of pesticides, i.e., registration review2

. The registration review program is 

intended to ensure that as the ability to assess risk evolves and as policies and practices 

change, all registered pesticides continue to meet the statutory standard of no unreasonable 

 2 http://www.epa.gov/oppsrrd1/registration_review/
14

adverse effects to human health and the environment. Changes in science, public policy, and 

pesticide use practices will occur over time. Through the registration review program, the 

Agency periodically reevaluates pesticides to make sure that as change occurs, products in 

the marketplace can be used safely.

Previous Risk Assessments

The most recent completed screening level risk assessment for use on cereals, sugarcane, and 

grasses grown for seed (USEPA 2011a, DP Barcode 377923 sub 387340) identified direct 

risks to terrestrial plants (monocots and dicots). Indirect risks were assumed for all listed 

taxa because of their potential dependence on terrestrial plants for survival. These 

conclusions are different than those identified in this risk assessment because turf is 

considered in this risk assessment and the risk assessment process for terrestrial invertebrates 

has changed (USEPA 2012). In addition, the Agency received acute data for passerine birds 

with a lower endpoint than the data that were available for the last risk assessment. 

Stressor Source and Distribution

MECHANISM OF ACTION

Trinexapac-ethyl is a systemic plant growth regulator that is used to slow the growth of 

turfgrasses by 40 to 60 percent over a 4 to 8 week period. It is a cyclohexadione plant 

growth regulator that inhibits gibberellic acid biosynthesis and is absorbed by plant foliage. 

Gibberellic acid is necessary for cellular elongation during a plant’s growth period. The free 

acid of trinexapac-ethyl inhibits the hydroxylation of gibberellin20 to gibberellin1 by 

competitively inhibiting the regulatory enzyme 3-hydroxylase. The lack of gibberellic acid 

causes plants to have shortened internode lengths and shorter cell lengths, thereby reducing 

the overall length of leaves and stolons. The slower plant growth induced by the application 

trinexapac-ethyl is temporary and at normal application rates, plants usually resume regular

growth approximately 8 weeks after application.

OVERVIEW OF PESTICIDE USE AND USAGE

Trinexapac-ethyl is a plant growth regulator that is currently registered for application to turf, 

wheat, barley, oats, triticale, sugarcane, and grasses grown for seed. For turf, it alters growth 

habit to form more compact plants. For the other uses, it reduces lodging (cereal grains and 

grasses grown for seed), promotes ripening, shortens the internode for seed piece production,

and increases/maintains the sugar content in sugarcane. Registered application methods for 

trinexapac-ethyl are chemigation and broadcast (aerial and ground). Thirteen different 

companies currently have registered products with trinexapac-ethyl product concentrations 

ranging from 0.15 to 25.5 percent. Forms include emulsifiable concentrate, granular, liquid, 

micro-encapsulated, and wettable powder (Tables 1 and 2). 

Trinexapac-ethyl was first registered in 1993 for the management of warm and cool season 

turfgrasses. Specific usage data are not available for trinexapac-ethyl. Most of registrations 

are for turf (e.g., lawns, golf courses, edging along sidewalks, flowerbeds). Wheat, barley, 

oats, triticale, and sugarcane were added to the label in 2012 as the first food use. At the 

same time, the grasses grown for seed registration, which was formerly only for Wisconsin, 

Minnesota, Idaho, and Oregon, was expanded to include the entire United States. 
15

Table 1. Current registrations for trinexapac-ethyl

Product Name Registrant

EPA 

Registration #

(latest label 

date)

Active 

Ingredient

(% w/w)

Form Use(s)

Trinexapac-Ethyl 

Technical

Syngenta Crop 

Protection

100-727

(2/17/12) 97 Technical chemical

Cool and warm season turfgrasses, 

seed, wheat, barley, oats, sugarcane

Primo Liquid Syngenta Crop 

Protection

100-729

(11/27/09) 12 Emulsifiable concentrate Cool and warm season turfgrasses

Primo WSB Syngenta Crop 

Protection

100-752

(10/20/03) 25 Wettable powder Cool and warm season turfgrasses

Lawn Primo G Syngenta Crop 

Protection

100-930

(9/3/10) 1 Granular Cool and warm season turfgrasses

Lawn Primo F Syngenta Crop 

Protection

100-931

(9/7/10) 1 Granular Cool and warm season turfgrasses

Primo Maxx Syngenta Crop 

Protection

100-937

(11/21/09) 11.3 Emulsifiable concentrate Cool and warm season turfgrasses

Palisade EC Syngenta Crop 

Protection

100-949

(1/28/13) 12 Emulsifiable concentrate

Grasses grown for seed, wheat, oat 

sugarcane

Palisade 2EC Syngenta Crop 

Protection

100-1241

(1/28/13) 25.5 Emulsifiable concentrate

Grasses grown for seed, wheat, oat 

sugarcane

Trinexapac-Ethyl 1 

ME

Syngenta Crop 

Protection

100-1401

(3/18/11) 11.3 Microencapsulated Cool and warm season turfgrasses

Nufarm T-PAC SPC 

MEC Plant Growth 

Regulator

Nufarm Americas 228-635

(12/18/09) 11.3 Emusifiable concentrate Cool and warm season turfgrasses

T-PAC E-PRO EC 

Plant Growth 

Regulator

Nufarm Americas 228-648

(1/4/07) 12 Emulsifiable concentrate Cool and warm season turfgrasses

The Andersons

0.15% TrinexapacEthyl + Fertilizer

The Andersons 

Lawn Fertilizer 

Division

9198-245

(5/8/09) 0.15 Granular Cool and warm season turfgrasses

The Andersons 

0.39% TrinexapacEthyl + Fertilizer

The Andersons 

Lawn Fertilizer 

Division

9198-246

(3/16/09) 0.39 Granular Cool and warm season turfgrasses

LPI T-Pack MEC 

Plant Growth 

Regulator

Loveland 

Products

34704-1005

(7/22/10) 11.3 Emulsifiable concentrate Cool and warm season turfgrasses

Trinexapac-Ethyl 

Technical Nufarm Limited 35935-66(11/25/09) 98 Technical chemical Cool and warm season turfgrasses

Quali-Pro T-NEX 1 

AQ

Makhteshim Agan 

of North America

66222-212

(1/6/11) 11.3 Emulsifiable concentrate Cool and warm season turfgrasses

SP5075 Turf Growth 

Regulator Sepro Corporation 67690-46(9/1/11)

5

13.26 

(flurprimidol)

Emulsifiable 

concentrate Cool and warm season turfgrasses

SP5114 Sepro Corporation 67690-56

(1/5/12)

3.5

7 

(paclobutrazol)

Soluble 

concentrate Cool and warm season turfgrasses

SP5411 Sepro Corporation 67690-57

(11/2/11)

1.4

5.6 

(paclobutrazol)

5.6 

(flurprimidol)

Emulsifiable 

concentrate Cool and warm season turfgrasses

GoldWing United 

Phosphorus

70506-259

(10/14/10) 11.3 Emulsifiable concentrate Cool and warm season turfgrasses

Provair PGR Prokoz 72112-11

(4/6/10) 11.3 Emulsifiable concentrate Cool and warm season turfgrasses
16

Product Name Registrant

EPA 

Registration #

(latest label 

date)

Active 

Ingredient

(% w/w)

Form Use(s)

Groom PGR Advan 83070-4

(9/22/09) 11.3 Emulsifiable concentrate Cool and warm season turfgrasses

Trinexapac-Ethyl 

Technical

Celsius Property 

B. V., Amsterdam

83558-31

(7/17/09) 97 Technical chemical Cool and warm season turfgrasses

Armor Tech PGR 113 

MC

United Turf 

Alliance

86064-3

(6/24/09) 11.3 Emulsifiable concentrate Cool and warm season turfgrasses

Trin-Pac Select Prime Source 89442-7

(1/4/13) 11.3 Emulsifiable concentrate Cool and warm season turfgrasses
17

Table 2. Use and application rate information for trinexapac-ethyl

Crop

Maximum 

Application 

Rate

Application 

Method

Maximum 

Number of 

Applications 

and Shortest 

Application 

Interval

(weeks)

Reg. #1

Cool and warm season turfgrasses Single max = 

0.34 lb ai/A

Yearly max = 

2.72 lb ai/A

Ground 

broadcast

Chemigation

8

4 weeks

100-727, 100-729, 

100-752, 100-930, 

100-931, 100-937, 

100-1401, 228-635, 

228-648, 9198-245, 

9198-246, 34704-

1005, 35935-66, 

66222-212, 67690-46, 

67690-56, 67690-57, 

70506-259, 72112-11, 

83070-4, 83558-31, 

86064-3, 89442-7

Single max = 

0.68 lb ai/A

Yearly max = 

2.72 lb ai/A

4

8 weeks

Single max = 

1.36 lb ai/A

Yearly max = 

2.72 lb ai/A

2

8 weeks

Single max = 

0.35 lb ai/A

Yearly max = 2.4 

lb ai/A

Granular 

broadcast

8

4 weeks2

100-937

Single max = 

0.44 lb ai/A

Yearly max = 

2.72 lb ai/A2

8

4 weeks

9198-245, 9198-246

Single max = 

0.88 lb ai/A

Yearly max = 2.5 

lb ai/A

8

4 weeks

100-930

Grasses grown for seed Single max = 0.5 

lb ai/A

Yearly max = 0.5 

lb ai/A

Ground or 

aerial broadcast

1

N/A

100-949, 100-1241

Wheat, barley, oats, triticale Single max = 

0.11 lb ai/A

Yearly max = 

0.11 lb ai/A

Ground or 

aerial broadcast

Chemigation

1

N/A

100-949, 100-1241

Sugarcane Single max = 

0.31 lb ai/A

Yearly max = 

0.31 lb ai/A

Ground or 

aerial broadcast

Chemigation

1

N/A

100-949, 100-1241
18

Crop

Maximum 

Application 

Rate

Application 

Method

Maximum 

Number of 

Applications 

and Shortest 

Application 

Interval

(weeks)

Reg. #1

N/A- not applicable 1

Application rates represent maximum application rate for a least one of the EPA Reg. # listed. Other labels 

may have slightly different application rates.

2

Assumed based on similar labels

Environmental Fate and Transport

SUMMARY OF ENVIRONMENTAL FATE

Based on the results of a laboratory soil volatility study, trinexapac-ethyl appears not to 

volatilize. This is supported by its low vapor pressure (1.62 x 10-5 mm Hg at 25o

C) (MRID 

41604203) and Henry’s Law (5.27 x 10-10 atm-m3/mol) constants (calculated from water 

solubility, vapor pressure and molecular weight) (Table 3).

Based on the batch equilibrium data, adsorption of trinexapac-ethyl (Koc = 60 to 635 ml/goc; 

MRID 41563936 and 41663937) is characterized as being mobile to moderately mobile in 

the test soils3 (FAO Classification). In addition, adsorption data for trinexapac acid (Koc = 

144 to 609 mL/goc) is characterized as being moderately mobile in test soils. Terrestrial field 

dissipation data indicated that under typical use, the vast majority of the compound and its 

major metabolite, trinexapac acid, dissipate in the grass and thatch and sod layer by study 

termination. Following the final application, dissipation half-lives were less than 3 days for 

trinexapac-ethyl and ranged from 5.1 to 36.5 days for trinexapac-acid (MRID 48043710, 

48043711). It is important to note that this 36.5 day (dissipation) half-life for the acid is 

longer than the 5.2 day 90th percentile TTR (degradation) half-life modeled as the aerobic 

soil input parameter in this assessment. This may be from differences between laboratory 

(degradation) studies and field (dissipation) studies.

Trinexapac-ethyl is stable to hydrolysis in acidic and neutral conditions and hydrolyzes under 

basic conditions (t1⁄2 = 8.1 days; MRID 41563930). After further review, the neutral pHs of 

environmental compartments in the soil and aquatic metabolism studies suggest microbialmediated hydrolysis. Photodegradation does not appear to be a major degradation pathway 

in aqueous and soil environments. The aqueous photolysis study shows an environmental 

phototransformation half-life of about 18 days (MRID 46809302). The compound was 

considered stable in the soil photolysis study since the extrapolated half-life was well beyond 

the duration of the study (MRID 42081406). 

Biodegradation appears to be the major dissipation pathway for trinexapac-ethyl, specifically 

aerobic biotransformation in terrestrial environments and aerobic and anaerobic 

 3 USEPA. 2006. Standardized Soil Mobility Classification Guidance. U.S. Environmental Protection Agency, Office of 

Prevention, Pesticides and Toxic Substances, Office of Pesticide Programs, Environmental Fate and Effects Division,

Memorandum. April 21, 2006.
19

biotransformation in aquatic environments. Half-lives ranged from 2.8 hours in a loam soil 

to 4.3 days in a loamy sand soil in an aerobic soil metabolism study (MRID 46809303). 

Half-lives ranged from 2.8 days in a river water-sand sediment system to 4.0 days in a pond 

water-sandy clay loam sediment system in an aerobic aquatic metabolism study (MRID 

46809304). Half-lives averaged 3.5 days in pond water and lake water-sediment systems in 

an anaerobic aquatic metabolism study (MRID 48043712). 

Biodegradation was slower under anaerobic soil conditions. The estimated half-life is about 

25 days in a sandy loam soil (MRID 41563933).

For trinexapac ethyl, the range of bioconcentration factors (BCFs) for edible tissue, nonedible tissue, and whole fish (from 2.5 to 11) indicate a low potential for bioconcentration in 

fish (MRID 41604207).

The major environmental degradates of trinexapac-ethyl include its free acid CGA-179500, 

CGA-313458, an open chain cyclohexane ring, CO2 and an unidentified hydroproduct M3. 

Trinexapac acid’s (CGA-179500) maximum formation percentages occurred during 

hydrolysis at 91%, soil photolysis (52%), aerobic soil metabolism (44%), aerobic aquatic 

metabolism (71%) and anaerobic aquatic metabolism (88%). CGA-313458 maximum 

formation was 22% occurring in a hydrolysis study. The unidentified hydroproduct M3 

maximum formation was 35% occurring during a hydrolysis study. The open chain 

cyclohexane ring maximum formation was 12% occurring during a soil photolysis study. In 

addition, significant CO2 formation (mineralization) occurred during the aqueous photolysis 

(20%), aerobic soil metabolism (71%), aerobic aquatic metabolism (73%), and aerobic 

aquatic metabolism (85%) studies. Structures and MRID references can be found in 

Appendix C. 

The parent ester (including its free acid CGA-179500), CGA-313458, an open chain 

cyclohexane ring, and an unidentified hydroproduct – M3) was included in a Total Toxic 

Residue (TTR) approach (Table 4) for this risk assessment. It is important to note that the 

TTR approach is used to estimate aquatic exposure. EECs were not calculated for any of the 

major degradates for trinexapac-ethyl because toxicity data were not available. It was 

assumed that the degradates have similar toxicity as their parent – trinexapac-ethyl.

Table 3. Physical, chemical, and environmental fate properties for trinexapac-ethyl

Property Value Comment Source

Molecular Mass (g/mol) 252.3 -- MRID 41604201

Vapor Pressure at 25°C 

(torr)

1.62 x 10-5 -- MRID 41604203

Henry’s Law Constant

(atm-m3/mol)

5.27 x 10-10 calculated KH = (vapor pressure *

molecular weight) / (760* 

water solubility)

Solubility in Water 

(mg/L at 25o)

2800

10200

21100

at pH 4.9 

at pH 5.5 

at pH 8.2

MRID 41604203
20

Property Value Comment Source

Organic Carbon 

Partition Coefficient 

(KOC) (L/kgOC)

60 to 635 (ethyl)

144 to 609 (acid)

range of values MRID 41663936

MRID 41663937

Aerobic Soil 

Metabolism Half-life 

(days)

2.8 hours 

9.6 hours

4.3 days

individual values MRID 46809303

Anaerobic Soil 

Metabolism Half-life 

(days)

25 sandy loam soil MRID 41563933

Aerobic Aquatic 

Metabolism Half-life 

(days)

2.8 

4.0

individual values MRID 46809304

Anaerobic Aquatic 

Metabolism Half-life 

(days)

3.5 average value in pond 

water and lake watersediment systems

MRID 48043712

Hydrolysis Half-lives 

(days)

Stable

8.1

pH 7

pH 9 (alkaline-based)

MRID 41563930

MRID 46809301

Aqueous Photolysis

Half-life (days)

18 environmental 

phototransformation 

half-life

MRID 46809302

Soil Photolysis

Half-life (days)

stable extrapolated half-life is 

well beyond the duration 

of the study

MRID 42081406

Terrestrial Field 

Dissipation (days)

< 3 (ethyl)

5.1 to 36.5 (acid)

ethyl and acid values MRID 48043710

MRID 48043711

Receptors

EFFECTS TO ORGANISMS

Registrant Submitted Studies for Trinexapac-Ethyl

The registrant(s) have submitted a number of studies in support of trinexapac-ethyl new use 

registrations and registration review that are considered scientifically sound for use in risk 

assessments. Studies are available for freshwater fish (acute and chronic), estuarine/marine 

fish (acute), freshwater invertebrates (acute and chronic), estuarine/marine invertebrates 

(acute), non-vascular aquatic plants, vascular aquatic plants, birds (acute and chronic), 

mammals (acute and chronic), honeybee (acute contact), and terrestrial plants (monocots and 

dicots).

Open Literature Studies

Open literature studies from the ECOTOX database were reviewed for inclusion in the risk 

assessment. Studies were screened to determine if they provided information about species 

for which EFED does not usually receive information, or lower toxicity endpoints than 
21

registrant-submitted studies. Several studies on fungi (a taxon for which information is not 

available) and several studies on grass (lower monocot toxicity endpoints) were identified

and reviewed. All of the ECOTOX papers that were not used and rationales for exclusion are 

listed in Appendix D.

Some aquatic toxicity data for the degradates were available in the European Footprint 

Database (http://sitem.herts.ac.uk/aeru/footprint/en/index.htm). These data were not used in 

the risk assessment because the TTR analysis yielded high end EECs that did not exceed the 

LOC for aquatic species. Consequently, there was no reason to further refine the assessment 

with these data.

INCIDENT DATABASE REVIEW

Incident databases were searched on May 16, 2013. A review of the Ecological Incident 

Information System (EIIS, version 2.1.1), which is maintained by the Agency’s Office of 

Pesticide Programs, the Aggregate Summary Module of OPP’s Incident Database, and the 

Avian Monitoring Information System (AIMS), which is maintained by the American Bird 

Conservancy, was conducted for trinexapac-ethyl.

Neither the EIIS nor the AIMS database identified any adverse ecological incidents involving 

trinexapac-ethyl. Although incident reporting is required under FIFRA Section 6(a)(2), the 

absence of reports in EIIS does not indicate that the chemical has no effects on wildlife; 

rather, it is possible that incidents have gone unreported. Two incidents were documented in 

the Aggregate Incident Report. One incident was reported as a minor fish and wildlife 

incident and involved Primo Liquid between 7/1/00 and 9/30/00. The other was reported as a 

minor plant incident and involved Palisade EC between 11/1/03 and 10/31/04. No other 

information was available.

DATA GAPS IDENTIFIED

The following toxicity data gaps have been identified:

• OPPTS 850.1350- Chronic Estuarine/Marine Invertebrate Toxicity Test

• OPPTS 850.1400- Chronic Estuarine/Marine Fish Toxicity Test

• OECD 213- Acute Oral Honeybee Toxicity Test

• Non-Guideline- Honeybee Larvae Toxicity Test

These data were not identified as gaps in the trinexapac-ethyl problem formulation. At that

time the terrestrial invertebrate assessment for pesticides was conducted only using the acute 

contact LD50; acute oral data for adult honeybees and toxicity data for larval bees are a result 

of the Pollinator White Paper (USEPA 2012). For the chronic estuarine/marine invertebrate 

gap, the problem formulation proposed using an acute-to-chronic ratio to fill in the gap. 

However, the freshwater acute daphnid data is non-definitive; acute-to-chronic ratios are 

generally not calculated with non-definitive endpoints. This assessment also explores 

ECOSAR toxicity estimates and surrogate chemicals to represent this endpoint. For the 

chronic estuarine/marine fish data gap, the problem formulation proposed that 

estuarine/marine fish were less sensitive on an acute basis than freshwater fish. Therefore, 

the freshwater fish acute data could be adopted as an appropriate surrogate.
22

ECOSYSTEMS POTENTIALLY AT RISK

The ecosystems at risk are often extensive in scope, and as a result it may not be possible to 

be specific at the screening level. Trinexapac-ethyl is registered on food items (wheat, oat, 

barley, and sugarcane) and non-food items (grasses grown for seed and turf). In general 

terms, terrestrial ecosystems potentially at risk could include the areas next to treated fields, 

plantations, roadsides, fencerows, equipment storage areas, paved areas, golf courses, and 

lawns. Affected ecosystems could include cultivated fields, fencerows and hedgerows, 

meadows, fallow fields or grasslands, woodlands, riparian habitats and other uncultivated 

areas. 

Aquatic ecosystems potentially at risk include water bodies adjacent to or downstream from 

the treated area and might include impounded bodies such as ponds, lakes and reservoirs, or 

flowing waterways such as streams or rivers. For uses in coastal areas, aquatic habitat also 

includes marine ecosystems and estuaries. 

All of the agricultural uses apply trinexapac-ethyl as a foliar spray (ground or aerial) to 

vegetation. The turf use can be applied as a spray or broadcast treatment. Given the 

widespread distribution of golf courses, lawns, and other turf-covered areas, it is expected 

that trinexapac-ethyl applications could occur in most areas of the United States. 

Conceptual Model

For a chemical to pose an ecological risk, it must reach ecological receptors in biologically 

significant concentrations. An exposure pathway is the means by which a pesticide moves in 

the environment from a source to an ecological receptor. For an ecological exposure 

pathway to be complete, it must have a source, a release mechanism, an environmental 

transport medium, a point of exposure for ecological receptors, and a feasible route of 

exposure.

The conceptual model (Figures 1 and 2) depicts the potential pathways for ecological risk 

associated with trinexapac-ethyl (including its four major degradates) use. The conceptual 

model provides an overview of the expected exposure routes for organisms within the 

trinexapac-ethyl action area. For terrestrial organisms, the major route of exposure 

considered is the dietary route; consumption of food items such as plant leaves or insects that 

have trinexapac-ethyl residues as a result of spraying and drift. Exposure through inhalation 

is unlikely given trinexapac-ethyl’s low vapor pressure and the results of EFED’s Screening 

Tool for Inhalation Risk (STIR v. 1.0). EFED’s Screening Imbibition Program (SIP v. 1.0) 

indicated that drinking water exposure alone is a potential concern for birds or mammals 

(acute and chronic exposures) (Appendix E). 

For aquatic animal species, the major routes of exposure are considered to be via the 

respiratory surface (gills) or the integument.

Direct contact and/or root uptake is the major route of exposure for terrestrial and wetland 

(riparian) plants, while aquatic plants may be exposed via direct uptake and adsorption. 

Estimated exposure concentrations for all organisms are obtained through the use of several 

Agency exposure models.
23

** Route of exposure includes only ingestion of fish and aquatic invertebrates

Stressor

Source

Receptors

Attribute

Change

Trinexapac-Ethyl ( and Degradates) Applications for All Registered Uses

Spray drift

Aquatic animals

Invertebrates 

Vertebrates

**Piscivorous mammals 

and birds

Individual organisms

Reduced survival

Reduced growth

Reduced reproduction

Food chain

Reduction in algae and 

vascular plants

Reduction in prey

Modification of PCEs 

related to prey availability

Habitat integrity

Reduction in primary productivity

Reduced cover

Community change

Modification of PCEs related to 

habitat

Surface water/

Sediment

Runoff

Aquatic Animals

Invertebrates

Vertebrates

Exposure

Media

Uptake/gills 

or integument

Ingestion Ingestion

Atmospheric 

transport

Wet/dry deposition

Soil Leaching to

Groundwater

Uptake/gills 

or integument

Aquatic Plants

Non-vascular

Vascular

Uptake/cell, 

roots, leaves Riparian plants

terrestrial 

exposure 

pathways see 

Figure 2

Figure 1. Conceptual model for the aquatic effects of trinexapac-ethyl applications. Dotted 

lines indicate the pathway is not expected to be significant. 

Stressor

Source

Attribute

Change

Trinexapac-Ethyl (and Degradates) Applications for All Registered Uses

Direct

application Spray drift

Terrestrial 

vertebrates

Terrestrial 

Inverts

Individual organisms

Reduced survival

Reduced growth

Reduced reproduction

Food chain

Reduction in prey and food

Modification of PCEs 

related to prey availability

Habitat integrity

Reduction in primary productivity

Reduced cover

Community change

Modification of PCEs related

to habitat

Terrestrial plants

grasses/forbs, fruit, seeds 

(trees, shrubs)

Runoff

Terrestrial 

vertebrates 

Exposure Media 

& Receptors Soil

Ingestion

Ingestion

Dermal uptake/Ingestion

Atmospheric 

transport

Root uptake/contact

Wet/dry deposition

Ingestion

Leaching to

Groundwater Irrigation 

water

Figure 2. Conceptual model for the terrestrial effects of trinexapac-ethyl applications.

Risk Hypothesis

For trinexapac-ethyl and its degradates, the following ecological risk hypotheses are being 

tested in this baseline risk assessment: 
24

Terrestrial Environment

• Exposure to trinexapac-ethyl and degradate residues on insects, seeds, foliage, and 

other plant parts from direct deposition or spray drift from the labeled use of the 

pesticide has the potential to cause reduced survival, growth and reproduction to 

terrestrial vertebrates (birds, mammals, reptiles, terrestrial-phase amphibians) and 

terrestrial invertebrates.

• Exposure to trinexapac-ethyl and degradate residues on foliage, roots, or other plant 

parts from spray drift alone or from runoff from labeled use of the pesticide has the 

potential to result in reduced survival and biomass to upland plants and 

riparian/wetland plants in areas adjacent to a treated area. 

Aquatic Environment

• Exposure to trinexapac-ethyl and degradate residues in water from spray drift or 

runoff from the labeled uses of the herbicide has the potential to cause reduced 

survival, growth and reproduction to aquatic invertebrates, fish, and plants (vascular 

and non-vascular) in surface waters adjacent to a treated area.

Analysis Plan

In registration review, pesticide ecological risk assessments will follow the Agency’s 

Guidelines for Ecological Risk Assessment and will be in compliance with the paper entitled 

“Overview of the Ecological Risk Assessment Process in the Office of Pesticide Programs, 

U.S. Environmental Protection Agency” (USEPA 2004).

The focus of an ecological risk assessment is on both the toxic effects of a pesticide to nontarget organisms and the potential routes of the pesticide’s exposure to non-target organisms. 

In addition to addressing a pesticide’s toxic effects and potential routes of exposure, an 

ecological risk assessment addresses the uncertainties associated with a pesticide’s risk to 

non-target organisms.

MEASURES TO EVALUATE THE RISK HYPOTHESIS AND CONCEPTUAL MODEL

Measures of exposure are based on aquatic and terrestrial models that predict estimated 

environmental concentrations (EECs) of trinexapac-ethyl using maximum labeled application 

rates and methods of application. The model used to predict aquatic EECs is the PRZM 

[Pesticide Root Zone Model (PRZM v3.12.2)] and EXAMS [EXposure Analysis Modeling 

System (v2.98.4.6)]. The model used to predict terrestrial EECs on food items is T-REX

[Terrestrial Residue Exposure Model version 1.5.1 (August 20, 2012)]. The model used to 

derive EECs relevant to terrestrial and wetland plants is TerrPlant [Version 1.2.2 (10/29/09)].

MEASURES OF EFFECT

Data identified in the Effects Characterization Section are used as measures of effect for 

direct and indirect effects to non-target organisms. Data were obtained from registrant 

submitted studies or from open literature studies identified by ECOTOX. The 

ECOTOXicology database (ECOTOX) was searched to provide more ecological effects data 
25

and to bridge existing data gaps. ECOTOX is a source for locating single chemical toxicity 

data for aquatic life, terrestrial plants, and wildlife. ECOTOX was created and is maintained 

by the USEPA Office of Research and Development and the National Health and 

Environmental Effects Research Laboratory's Mid-Continent Ecology Division.

The acute measures of effect used for animals in this screening level assessment are the LD50, 

LC50, and EC50. LD stands for “Lethal Dose”, and LD50 is the amount of a material, given all 

at once, that is estimated to cause the death of 50% of the test organisms. LC stands for 

“Lethal Concentration” and LC50 is the concentration of a chemical that is estimated to kill 

50% of the test organisms. EC stands for “Effective Concentration” and the EC50 is the 

concentration of a chemical that is estimated to produce a specific effect in 50% of the test 

organisms. Endpoints for chronic measures of exposure for listed and non-listed animals are 

the NOAEL/NOAEC and NOEC. NOAEL stands for “No Observed-Adverse-Effect-Level” 

and refers to the highest tested dose of a substance that has been reported to have no harmful 

(adverse) effects on test organisms. The NOAEC (i.e., “No-Observed-Adverse-EffectConcentration”) is the highest test concentration at which none of the observed effects were 

statistically different from the control. The NOEC is the No-Observed-EffectsConcentration. For non-listed plants, only acute exposures are assessed (i.e., EC25 for 

terrestrial plants and EC50 for aquatic plants). 

INTEGRATION OF EXPOSURE AND EFFECTS

Risk characterization is the integration of exposure and ecological effects characterization to 

determine the potential ecological risk from agricultural and non-agricultural uses of 

trinexapac-ethyl, and the likelihood of direct and indirect effects to non-target organisms in 

aquatic and terrestrial habitats. The exposure and toxicity effects data are integrated to 

evaluate the risks of adverse ecological effects on non-target species. For the assessment of 

trinexapac-ethyl risks, the risk quotient (RQ) method is used to compare exposure and 

measured toxicity values. EECs are divided by acute and chronic toxicity values. The 

resulting RQs are then compared to the Agency’s levels of concern (LOCs) (USEPA 2004). 

There is no established acute listed or non-listed LOC for terrestrial invertebrates; however, 

an interim LOC of 0.4 has been established for honeybees and an interim LOC of 0.05 has 

been adopted for listed terrestrial invertebrates. The LOCs currently in use for birds, 

mammals, and aquatic species are based on 1975 regulations for the enforcement of FIFRA 

(40 CFR Part 154: 49005; 49007; 49016). Refer to Appendix F for addition information on 

the LOCs.

ANALYSIS OF CO-OCCURANCE OF FEDERALLY LISTED SPECIES WITH TRINEXAPAC-ETHYL

Consistent with the Agency’s responsibility under the Endangered Species Act (ESA), the 

Agency will evaluate risks to federally-listed threatened and/or endangered (listed) species 

from registered uses of trinexapac-ethyl. This assessment will be conducted in accordance 

with the Overview Document (USEPA 2004), provisions of the ESA, and the Services’ 

Endangered Species Consultation Handbook (U.S. FWS/NMFS, 1998).

In the case of a nation-wide risk assessment conducted under Registration Review, the action 

area will encompass the entire U.S. and its territories. The purpose of defining the action 

area as the entire U.S. and its territories is to ensure that the initial area of consideration 
26

encompasses all areas where the pesticide may be used now and in the future, including the 

potential for off-site transport via spray drift and downstream dilution. Additionally, the 

concept of a nationwide action area takes into account the potential for direct and indirect 

effects and any potential modification to critical habitat based on ecological effect measures 

associated with reduction in survival, growth, and reproduction, as well as the full suite of 

sub-lethal effects available in the effects literature. 

It is important to note that the nation-wide action area does not imply that direct and/or 

indirect effects and critical habitat modification are expected to or are likely to occur over the 

full extent of the action area, but rather to identify all listed species and critical habitat that 

may potentially be affected by the action. The Agency will use more rigorous analysis 

including consideration of available land cover data, toxicity data, exposure information, and 

species biology to determine areas where individual listed species and designated critical 

habitat may be affected or modified via endpoints associated with reduced survival, growth, 

or reproduction. 
27

Exposure Assessment

Aquatic Exposure Assessment

Monitoring Data

Trinexapac-ethyl and trinexapac acid were not included in the list of the analytes monitored 

in the U.S. surface and groundwater under the USGS’s National Water Quality Assessment 

(NAWQA) program. There were no available monitoring data at the time of this assessment.

Aquatic Exposure Modeling

Tier II screening-level surface water exposures for aquatic risk assessment were conducted 

for all registered uses. Modeled application rates represent the maximum use pattern of the 

proposed label for all uses. The aquatic exposure estimates presented in this assessment were 

based on the use of models. Several major environmental degradates, (free acid CGA179500, CGA-313458, an open chain cyclohexane ring, and an unidentified hydroproduct 

M3) were identified in the environmental fate and terrestrial field dissipation studies (see 

Appendix C for more information on the percent formation of the degradates). There are no 

Agency-reviewed toxicity data related to aquatic species for these major degradates that can 

be used to exclude any of the degradates listed above. Also, very limited environmental fate 

data are available for these degradates. Therefore, a total toxic residue (parent plus 

degradates of concern) approach is used and expected to provide protective exposure 

estimation for aquatic organisms exposed to the major degradates of trinexapac-ethyl. 

Essentially, this method simply extends the duration of the predicted EECs to account for the 

time it would take for both the parent and degradates of concern to dissipate in the 

environment. It assumes that the degradates have equivalent fate and ecotoxicity properties 

as the parent. 

Table 4. Total toxic residue (TTR) expression for trinexapac-ethyl1

Matrix Residues of Concern Structure

Drinking 

Water 

Trinexapac-Ethyl 

(parent)

CGA-179500

(acid)

O

O

OH

O

O

H3C

*

*

*

O

O

O

HO OH
28

Matrix Residues of Concern Structure

CGA-313458

Open chain 

cyclohexane ring

Hydroproduct M3 Unidentified

1 Based on ROCKS decision memorandum (D390121)

Table 5 shows the half-life comparison of trinexapac-ethyl (parent) and total toxic residue 

approach. The half lives differ from those in Table 3 because of the total toxic residue 

approach recommended by the ROCKS memorandum (USEPA 2011b, D390121). This is 

evident by the longer half-life values of the combined residues.

Table 5. Half-life comparison for the trinexapac-ethyl (parent) versus total toxic 

residue approach

Study Parent 

(Ethyl) 

t1/2 (days)

Acid 

t1/2 (days)

TTR Approach

t1/2 (days)

Aqueous Photolysis 18 No data 22.8

Aerobic Soil Metabolism 2.8 hrs to 4.3 No data 3.0 to 5.2 

Aerobic Aquatic Metabolism 2.8 to 4.0 No data 12.3 to 14.8

Anaerobic Aquatic 

Metabolism 

3.5 No data 56 to 290

Terrestrial Field Dissipation < 3 5 to 36.5 NA

NA = Not Applicable

TIER II PRZM/EXAMS Model

The Tier II model Pesticide Root Zone Model (PRZM v3.12.2) linked with EXposure 

Analysis Modeling System (EXAMS v2.98.4.6) via the model shell PRZM/EXAMS (PE 

v5.0, Nov. 15, 2006) was used to estimate baseline-level exposures for representative crop 

scenarios. The PRZM model simulates pesticide movement and transformation on and 

across the agricultural field resulting from crop applications. The EXAMS model simulates 

pesticide loading via runoff, erosion, and spray drift assuming a “standard” 1-ha pond, 2-m 

deep (20,000 m3) with no outlet that borders a 10-ha treated field. Simulations are run for 

multiple (usually 30) years, and the Agency estimates peak and running mean values that are 

expected once every ten years based on the daily values generated during the simulation. 

OH

O O O

O OH
29

The coupled PE models and users manuals are available from the U.S. Environmental 

Protection Agency Water Models Web-page http://www.epa.gov/oppefed1/models/water/.

Exposure estimates generated using this “standard” pond are intended to represent a wide 

variety of vulnerable water bodies that occur in the upper reaches of watersheds including 

prairie pot holes, playa lakes, wetlands, vernal pools, man-made and natural ponds, and 

intermittent and first-order streams. As a group, there are factors that make these water 

bodies more or less vulnerable than the standard surrogate pond. Static water bodies that 

have larger ratios of pesticide-treated drainage area to water body volume would be expected 

to have higher peak EECs than the standard pond. These water bodies will be either smaller 

in size or have large drainage areas. Smaller water bodies have limited storage capacity and 

thus may overflow and carry pesticide in the discharge, whereas the standard pond has no 

discharge. As watershed size increases, it becomes increasingly unlikely that the entire 

watershed is planted with a non-major single crop that is all treated simultaneously with the 

pesticide. Headwater streams can also have peak concentrations higher than the standard 

pond, but they likely persist for only short periods of time and are then carried and dissipated 

downstream. 

An ecological risk assessment was performed using PRZM/EXAMS modeling under the PE5 

shell with approved standard scenarios. The North Dakota wheat scenario was modeled to 

represent the cereals. The Florida and Louisiana sugarcane scenarios were modeled to 

represent sugarcane. A Pennsylvania and Florida turf scenario were modeled to represent 

grasses grown for seed. Application rates and methods were obtained from the proposed 

labels. The following maximum application rates were used: for cereals – 1 application at 

0.11 lb ai/A, for sugarcane – 1 application at 0.31 lb ai/A, and for grasses grown for seed – 1 

application at 0.5 lb ai/A. For turf, the following three application rates were modeled 

because of different rates on the labels: 8 apps at 0.34 lb ai/A, 4 apps at 0.68 lb ai/A, and 2 

apps at 1.36 lb ai/A. Foliar (aerial and ground) spray applications and chemigation methods

(except for turf) were modeled for these maximum use rates. 

For cereals, the initial application date for each scenario was 45 days before harvest based on 

the pre-harvest interval of 45 days and one application. For sugarcane, the initial application 

date for each scenario was 28 days before harvest based on the pre-harvest interval of 28 

days and one application. Since the pre-harvest interval can range from 28 to 60 days, 

multiple application dates were selected for the Louisiana sugarcane (aerial) scenario to

assess the effects of application timing. Turf scenarios were chosen to represent grasses 

grown for seed and application dates were based on a pre-harvest interval of 30 days and the 

emergence dates of the crop. To represent turf, the date of initial application was based on 

the maturation date from selected crop scenarios. In addition, chemical property input values 

were chosen in accordance with the current input parameter guidance4

. 

 4 USEPA. 2009. Guidance for Selecting Input Parameters in Modeling the Environmental Fate and Transport of Pesticides, 

Version 2.1. U.S. Environmental Protection Agency, Office of Chemical Safety and Pollution Prevention, Office of 

Pesticide Programs, Environmental Fate and Effects Division, October 22, 2009. 
30

Although modeling chemigation is not standard policy, an attempt was made by modeling 

spray drift at 0% with 100% application efficiency. However, irrigation was not accounted 

for which would reduce runoff. This may underestimate the exposure concentrations. This is 

an uncertainty in the modeling of chemigation.

Input parameters for the PRZM/EXAMS models are listed in Table 6. Explanations of 

various model input parameters are discussed below.

Table 6. PRZM/EXAMS input parameters for trinexapac-ethyl following the TTR 

approach

Input Parameter Value Comment Source

Scenario(s): Cereals: 

ND Wheat

Sugarcane: 

FL Sugarcane

LA Sugarcane

Grasses Grown for Seed

FL Turf

PA Turf

Turf:

FL Turf

PA Turf

representative scenarios 

for each use

PE5 Model website

http://www.epa.gov/

oppefed1/models/wat

er/#przmexamsshell

Maximum Single 

Application Rate

lbs ai/acre (kg ai/ha)

Cereals: 

0.11 (0.124)

Sugarcane: 

0.31 (0.348)

Grasses Grown for Seed

0.5

Turf: 

a.) 0.340 (0.382)

b.) 0.680 (0.764)

c.) 1.360 (1.530)

proposed rates Palisade® EC label

Palisade® 2EC label
31

Input Parameter Value Comment Source

Applications per 

Year

Cereals: 1

Sugarcane: 1

Grasses grown for seed: 1

Turf: 

a.) 8

b.) 4

c.) 2

Label directions. Label 

specifies rates per 

season. If there are 

multiple growing 

seasons per year, yearly 

rates may be higher. 

Palisade® EC label

Palisade® 2EC label

Application Interval 

(days)

Cereals: NA

Sugarcane: NA

Grasses grown for seed: NA

Turf: 

a.) 28 (4 weeks)

b.) 56 (8 weeks)

c.) 56 (8 weeks)

For cereals, sugarcane, 

and grasses grown for 

seed, modeled single 

application rate for 

conservative exposure. 

For turf, modeled 

various intervals as 

labels directed 

application timing to 

actively growing turf.

Palisade® EC 

EPA Reg. No. 100-

949

Palisade® 2EC 

EPA Reg. No. 100-

1241

Date of Initial 

Application

(scenario: daymonth)

Cereals: 

ND Wheat: 21-06

Sugarcane: 

FL Sugarcane: 03-12

LA Sugarcane: 03-12

Grasses Grown for Seed:

FL Turf: 02-15

PA Turf: 04-15

Turf: 

FL Turf: 01-02

PA Turf: 01-04

Date of initial 

application was 

calculated from the PreHarvest Interval (PHI) 

of 45 days for cereals, 

28 days for sugarcane, 

and 30 days for grasses 

grown for seed. For 

turf, the crop 

emergence date was 

selected as the date of 

initial application.

Crop Scenarios and 

proposed labels
32

Input Parameter Value Comment Source

Application Method Cereals: 

Foliar: aerial and ground

Chemigation

Sugarcane: 

Foliar: aerial and ground

Chemigation

Grasses Grown for Seed:

Foliar: aerial and ground

Chemigation

Turf: 

Foliar: ground (boom sprayer)

Chemigation

label directions Palisade® EC 

EPA Reg. No. 100-

949

Palisade® 2EC 

EPA Reg. No. 100-

1241

CAM Input 2 (foliar)

1 (chemigation)

1) soil applied, default 

incorporation depth, 

linearly decreasing with 

depth; 2) linear foliar 

based on crop canopy

US EPA, 2005

IPSCND Input 2 (all uses) remaining pesticide on 

foliage is completely 

removed after harvest

US EPA, 2005

Spray Drift Fraction 0.05 (aerial)

0.01 (ground)

0 (chemigation)1

See footnote 1 for 

chemigation reference

Input parameter 

guidance (USEPA, 

2009) 

Application 

Efficiency

0.95 (aerial)

0.99 (ground)

1.0 (chemigation)

-- Input parameter 

guidance 

(USEPA, 2009)

Molecular Mass 

(g/mol)

252.3 -- MRID 41604201

Vapor Pressure at 

25°C (torr)

1.62 x 10-5 -- MRID 41604203

Henry’s Law 

Constant

(atm-m3/mol)

5.27 x 10-10 -- Calculated from 

water solubility, 

vapor pressure and 

molecular weight

Solubility in Water 

(mg/L)

10200 at pH 5.5 MRID 41604203
33

Input Parameter Value Comment Source

Organic Carbon 

Partition Coefficient 

(KOC) (L/kgOC)

416 2 represents the average 

KOC from 4 values for 

the acid (CGA-163935)

MRID 41663937

Aerobic Soil 

Metabolism Half-life 

(days)

5.2 3 represents the 90th

percentile confidence 

bound on the mean 

half-life of 3 values

MRID 46809303

Appendix B.2

Aerobic Aquatic 

Metabolism Half-life 

(days)

17.4 4 represents the 90th

percentile confidence 

bound on the mean 

half-life of 2 values

MRID 46809304

Appendix B.3

Anaerobic Aquatic 

Metabolism Half-life 

(days)

533 5 represents the 90th

percentile confidence 

bound on the mean 

half-life of 2 values

MRID 48043712

Appendix B.4

Hydrolysis Half-lives 

(days)

0 (stable) pH 7 MRID 41563930

MRID 46809301

Aqueous Photolysis

Half-life (days)

22.8 6 recalculated 

environmental 

phototransformation 

half-life

MRID 46809302

Appendix B.1

NA = Not Applicable

1 = Chemigation (< 1% spray drift as described in http://www.agdrift.com/PDF_FILES/Chem.pdf - modeled as 

0%)

2 = The average Koc obtained from four values (144, 328, 581 and 609) for the acid (CGA-163935). This value 

was modeled because of conversion of the ester to the acid in the environment. 

3 = Following the Total Toxic Residue (TTR) approach, this value represents the 90th percentile confidence 

bound on the mean half-life of 3 values (3.0, 3.6 and 5.2). See Appendix B.2

4 = Following the Total Toxic Residue (TTR) approach, this value represents the 90th percentile confidence 

bound on the mean half-life of 2 values (12.3 and 14.8). See Appendix B.3

5 = Following the Total Toxic Residue (TTR) approach, this value represents the 90th percentile confidence 

bound on the mean half-life of 2 values (290 and 56). See Appendix B.4

6 = Following the Total Toxic Residue (TTR) approach, this value represents the recalculated environmental 

phototransformation half-life. See Appendix B.1

Aquatic Exposure Modeling Results

The aquatic EECs for the various scenarios and application methods are listed in Table 7. 

The PA turf scenario (application rate of 1.36 lb ai/A) yielded the highest peak EEC (6.78 μg 

ai/L) and 60-day EEC (2.81 μg ai/L). The LA sugarcane scenario had the highest 21-day 

EEC (5.18 μg ai/L).
34

Table 7. Estimated environmental concentrations (EECs) for surface water based on 

selected crop scenarios following the TTR approach

Proposed 

Label Use

PRZM/EXAMS

Scenario1

(first app date)

Method2

Maximum 

Application Rate

(interval between 

applications)

Peak 

EEC

(μg/L)

21-day 

EEC

(μg/L)

60-day 

EEC 

(μg/L)

Palisade® EC and Palisade® 2EC Plant Growth Regulator Registered Turf Labels

Cereals

(Wheat, 

Barley, Oats, 

Triticale) 

ND Wheat

(June 21 – foliar) A 1 app @ 0.11 lb ai/A 0.41 0.31 0.22

ND Wheat

(June 21 – foliar) G 1 app @ 0.11 lb ai/A 0.25 0.18 0.12

ND Wheat

(June 21 –

chemigation)

C 1 app @ 0.11 lb ai/A 0.21 0.16 0.10

Sugarcane

FL Sugarcane

(December 03 – foliar) A 1 app @ 0.31 lb ai/A 3.31 2.56 1.14

FL Sugarcane

(December 03 – foliar) G 1 app @ 0.31 lb ai/A 2.98 2.42 0.97

FL Sugarcane

(December 03 –

chemigation)

C 1 app @ 0.31 lb ai/A 2.90 2.34 0.94

LA Sugarcane

(December 03 – foliar) A 1 app @ 0.31 lb ai/A 6.63 5.18 2.24

LA Sugarcane

(November 26 – foliar) A 1 app @ 0.31 lb ai/A 4.67 3.84 2.10

LA Sugarcane

(November 19 – foliar) A 1 app @ 0.31 lb ai/A 4.36 3.49 2.33

LA Sugarcane

(November 12 – foliar) A 1 app @ 0.31 lb ai/A 3.70 3.14 2.14

LA Sugarcane

(November 05 – foliar) A 1 app @ 0.31 lb ai/A 4.09 3.41 2.58

LA Sugarcane

(November 01 – foliar) A 1 app @ 0.31 lb ai/A 3.36 2.68 1.92

LA Sugarcane

(December 03 – foliar) G 1 app @ 0.31 lb ai/A 6.24 4.88 2.10

LA Sugarcane

(December 03 –

chemigation)

C 1 app @ 0.31 lb ai/A 6.14 4.81 2.06

Grasses 

Grown for 

Seed

FL Turf 

(February 15 – foliar) A 1 app @ 0.5 lb ai/A 1.41 1.12 0.76

FL Turf

(February 15 – foliar) G 1 app @ 0.5 lb ai/A 0.31 0.26 0.19

FL Turf

(February 15 – foliar) C 1 app @ 0.5 lb ai/A 0.13 0.10 0.06

PA Turf A 1 app @ 0.5 lb ai/A 1.45 1.22 0.91
35

Proposed 

Label Use

PRZM/EXAMS

Scenario1

(first app date)

Method2

Maximum 

Application Rate

(interval between 

applications)

Peak 

EEC

(μg/L)

21-day 

EEC

(μg/L)

60-day 

EEC 

(μg/L)

(April 15 – foliar)

PA Turf

(April 15 – foliar) G 1 app @ 0.5 lb ai/A 0.55 0.44 0.31

PA Turf

(April 15 – foliar) C 1 app @ 0.5 lb ai/A 0.37 0.30 0.19

Turf

FL Turf

(February 1 – foliar)

G

8 app @ 0.34 lb ai/Q

(28 days) 1.58 1.03 0.78

4 app @ 0.68 lb ai/A

(56 days) 2.14 1.49 0.94

2 app @ 1.36 lb ai/A

(56 days) 4.28 2.98 1.77

C

8 app @ 0.34 lb ai/Q

(28 days) 0.63 0.44 0.25

4 app @ 0.68 lb ai/A

(56 days) 0.91 0.60 0.38

2 app @ 1.36 lb ai/A

(56 days) 1.55 1.16 0.76

PA Turf

(April 01 – foliar)

G

8 app @ 0.34 lb ai/A

(28 days) 2.80 2.14 1.57

4 app @ 0.68 lb ai/A

(56 days) 4.45 3.49 2.24

2 app @ 1.36 lb ai/A

(56 days) 6.78 4.79 2.81

C

8 app @ 0.34 lb ai/A

(28 days) 1.22 0.87 0.54

4 app @ 0.68 lb ai/A

(56 days) 2.37 1.71 1.04

2 app @ 1.36 lb ai/A

(56 days) 3.86 2.75 1.72

1 Bold numbers denote maximum EEC values.

2 A = aerial application, G = ground application, C = chemigation

Terrestrial Exposure

Dietary-Based Trinexapac-Ethyl Residue Levels

The Agency uses the T-REX model (v. 1.5.1, USEPA, August 20, 2012) to estimate the 

terrestrial animal exposure values resulting from possible dietary ingestion of trinexapacethyl residues on vegetative matter and insects present on non-food and food crops from 

exposure to trinexapac-ethyl. It is assumed that the degradates from trinexapac-ethyl are 

equivalent in their toxicity to the parent and are accounted for in the conservative 35 day half 

life. In all screening-level assessments, the organisms are assumed to consume 100% of their 

diet as one food type. This model incorporates the Kenaga nomograph, as modified by 
36

Fletcher et al. (1994), which is based on a large set of actual field residue data. The upper 

limit values from the nomograph represent the 95th percentile of residue values from actual 

field measurements (Hoerger and Kenaga, 1972). T-REX was employed to estimate (1) 

EECs for different food items for birds and mammals, (2) dose/diet based risk to birds as 

well as dose based risk to mammals, and (3) EECs for arthropods to estimate risk to 

terrestrial invertebrates from direct contact. The tall grass EECs were used to evaluate risk 

from acute oral exposure for terrestrial invertebrates. 

Results of the T-REX modeling of trinexapac-ethyl residue levels on those dietary food items 

which potentially occur on some treated fields, for terrestrial invertebrates, mammals, and 

birds5 are provided in Tables 8 through 10. Residue levels for dietary items were calculated 

for all foliage spray applications. Granular formulations are assessed based on the exposure 

expected in a square foot (LD50/ft2

). 

Results include dietary-based values [i.e., milligrams of trinexapac-ethyl per kilogram of diet 

(mg/kg-diet)], and both an upper-bound and mean estimate of these exposure levels. The 

upper-bound values are derived using the upper-bound Kenaga nomogram which used the 

highest of the highest normalized residue values from a number of studies, as a tolerance 

limit approach.

As birds are also used as a surrogate for reptiles and terrestrial-phase amphibians within this 

assessment, it is assumed that dose-based exposure levels for these animals are the same as 

birds (i.e., food ingestion rate per body weight for a bird is the same as for an amphibian and 

reptile). However, reptiles and amphibians have a lower ingestion rate for a given body 

weight than birds (USEPA 1993). Therefore, the dose-based EECs presented here represent 

an overestimate of exposure for reptiles and amphibians of a given body size (see sample 

output in Appendix I).

Table 8. T-REX modeling scenarios

Use Maximum 

Application Rate 

(lb ai/A)

Number of 

Applications 

(Application 

Interval)

Wheat, barley, oat, and triticale 0.11 1

N/A

Sugarcane 0.31 1

N/A

Grasses grown for seed 0.5 1

N/A

Turf 0.34 8

 5 Birds are also used as a surrogate for reptiles and terrestrial-phase amphibians.
37

4 weeks

Turf 0.68 4

8 weeks

Turf 1.36 2

8 weeks

Granular Applications

Turf 0.35 7

4 weeks

Turf 0.44 6

4 weeks

Turf 0.88 3

4 weeks

Parameters used in T-REX Model: Foliar half life = 35 days; Avian LD50 – 813 mg ai/kgbw; Avian NOAEC – 200 mg ai/kg-diet (mallard duck); Mammal LD50 = 4212 mg ai/kg-bw 

(rat); Mammal NOAEL = 594 mg ai/kg-bw (rat)

Table 9. Avian trinexapac-ethyl upper bound EEC values 

Feeding Category

Dietarybased EECs 

(mg/kg-food 

item)

Dose-based EECs (mg/kg-bw)

Small

(20 g)

Medium

(100 g) Large

(1000 g)

Wheat, barley, oat, and triticale

1 app at 0.11 lb ai/A

Short grass 26.40 30.07 17.15 7.68

Tall grass 12.10 13.78 7.86 3.52

Broadleaf plants 14.85 16.91 9.64 4.32

Fruits/pods 1.65 1.88 1.07 0.48

Arthropods 10.34 11.78 6.72 3.01

Seeds 1.65 0.42 0.24 0.11

Sugarcane

1 app at 0.31 lb ai/A

Short grass 74.40 84.73 48.32 21.63

Tall grass 34.10 38.84 22.15 9.92

Broadleaf plants 41.85 47.66 27.18 12.17

Fruits/pods 4.65 5.30 3.02 1.35

Arthropods 29.14 33.19 18.92 8.47

Seeds 4.65 1.18 0.67 0.30

Grasses grown for seed

1 app at 0.5 lb ai/A
38

Feeding Category

Dietarybased EECs 

(mg/kg-food 

item)

Dose-based EECs (mg/kg-bw)

Small

(20 g)

Medium

(100 g) Large

(1000 g)

Short grass 120.00 136.67 77.93 34.89

Tall grass 55.00 62.64 35.72 15.99

Broadleaf plants 67.50 76.88 43.84 19.63

Fruits/pods 7.50 8.54 4.87 2.18

Arthropods 47.00 53.53 30.52 13.67

Seeds 7.50 1.90 1.08 0.48

Turf

8 apps at 0.34 lb ai/A (4 weeks)

Short grass 189.44 215.75 123.03 55.08

Tall grass 86.82 98.88 56.39 25.25

Broadleaf plants 106.56 121.36 69.20 30.98

Fruits/pods 11.84 13.48 7.69 3.44

Arthropods 74.20 84.50 48.19 21.57

Seeds 11.84 3.00 1.71 0.77

Turf

4 apps at 0.68 lb ai/A (8 weeks)

Short grass 240.65 274.08 156.29 69.97

Tall grass 110.30 125.62 71.63 32.07

Broadleaf plants 135.37 154.17 87.91 39.36

Fruits/pods 15.04 17.13 9.77 4.37

Arthropods 94.26 107.35 61.21 27.41

Seeds 15.04 3.81 2.17 0.97

Turf

4 apps at 1.36 lb ai/A (8 weeks)

Short grass 481.31 548.16 312.58 139.95

Tall grass 220.60 251.24 143.27 64.14

Broadleaf plants 270.74 308.34 175.83 78.72

Fruits/pods 30.08 34.26 19.54 8.75

Arthropods 188.51 214.70 122.43 54.81

Seeds 30.08 7.61 4.34 1.94

Table 10. Mammalian trinexapac-ethyl upper bound EEC values

Feeding Category

Dietarybased EECs 

(mg/kg-food 

item)

Dose-based EECs (mg/kg-bw)

Small

(15 g)

Medium

(135 g) Large

(1000 g)

Wheat, barley, oat, and triticale

1 app at 0.11 lb ai/A

Short grass 26.40 25.17 17.40 4.03

Tall grass 12.10 11.54 7.97 1.85
39

Feeding Category

Dietarybased EECs 

(mg/kg-food 

item)

Dose-based EECs (mg/kg-bw)

Small

(15 g)

Medium

(135 g) Large

(1000 g)

Broadleaf plants 14.85 14.16 9.79 2.27

Fruits/pods 1.65 1.57 1.09 0.25

Arthropods 10.34 9.86 6.81 1.58

Seeds 1.65 0.35 0.24 0.06

Sugarcane

1 app at 0.31 lb ai/A

Short grass 74.40 70.93 49.03 11.37

Tall grass 34.10 32.51 22.47 5.21

Broadleaf plants 41.85 39.90 27.58 6.39

Fruits/pods 4.65 4.43 3.06 0.71

Arthropods 29.14 27.78 19.20 4.45

Seeds 4.65 0.99 0.68 0.16

Grasses grown for seed

1 app at 0.5 lb ai/A

Short grass 120.00 114.41 79.07 18.33

Tall grass 55.00 52.44 36.24 8.40

Broadleaf plants 67.50 64.36 44.48 10.31

Fruits/pods 7.50 7.15 4.94 1.15

Arthropods 47.00 44.81 30.97 7.18

Seeds 7.50 1.59 1.10 0.25

Turf

8 apps at 0.34 lb ai/A (4 weeks)

Short grass 189.44 180.61 124.83 28.94

Tall grass 86.82 82.78 57.21 13.26

Broadleaf plants 106.56 101.59 70.22 16.28

Fruits/pods 11.84 11.29 7.80 1.81

Arthropods 74.20 70.74 48.89 11.34

Seeds 11.84 2.51 1.73 0.40

Turf

4 apps at 0.68 lb ai/A (8 weeks)

Short grass 240.65 274.08 156.29 69.97

Tall grass 110.30 125.62 71.63 32.07

Broadleaf plants 135.37 154.17 87.91 39.36

Fruits/pods 15.04 17.13 9.77 4.37

Arthropods 94.26 107.35 61.21 27.41

Seeds 15.04 3.81 2.17 0.97

Turf

4 apps at 1.36 lb ai/A (8 weeks)

Short grass 481.31 458.89 317.15 73.53

Tall grass 220.60 210.32 145.36 33.70
40

Feeding Category

Dietarybased EECs 

(mg/kg-food 

item)

Dose-based EECs (mg/kg-bw)

Small

(15 g)

Medium

(135 g) Large

(1000 g)

Broadleaf plants 270.74 258.13 178.40 41.36

Fruits/pods 30.08 28.68 19.82 4.60

Arthropods 188.51 179.73 124.22 28.80

Seeds 30.08 6.37 4.40 1.02

For insects, only two EECs are calculated. The tall grass EEC represents the exposure 

through dietary intake whereas the arthropod EEC represents exposure through contact 

(Table 11) (USEPA 2012). Given that honeybee larval toxicity data were not available, only 

trinexapac-ethyl doses for adult bees are considered.

Table 11. Adult insect foliar spray upper-bound EEC values 

Use

EEC (based on tall 

grass)

(mg/kg-diet) (dose 

in μg ai/bee*)

EEC (based on 

arthropod)

(mg/kg-diet) 

(dose in μg 

ai/bee**)1

Wheat, barley, oat, and triticale

1 app at 0.11 lb ai/A 12.10 (3.53) 10.34 (1.32)

Sugarcane

1 app at 0.31 lb ai/A 34.10 (9.96) 29.14 (3.73)

Grasses grown for seed

1 app at 0.5 lb ai/A 55.00 (16.06) 47.00 (6.02)

Turf

8 apps at 0.34 lb ai/A (4 weeks) 86.82 (25.35) 31.96 (4.09)

Turf

4 apps at 0.68 lb ai/A (8 weeks) 110.30 (32.20) 63.92 (8.18)

Turf

4 apps at 1.36 lb ai/A (8 weeks) 220.60 (64.42) 127.84 (16.36)

*Conversion made by multiplying EEC by food consumption rate of adult bee (0.292 g/day)

**Conversion made by multiplying EEC by body weight of adult bee (0.128 g)

1

Based on single app at the highest single application rate if application interval is >5 days

Off-Field Terrestrial and Wetland/Riparian Plant Trinexapac-Ethyl Exposure 

TerrPlant 1.2.2 (10/29/09) is used as a Tier 1 model for screening level assessments. The 

model provides estimates of exposure to terrestrial plants from single pesticide applications; 

the model does not consider exposures to plants from multiple pesticide applications. 

TerrPlant derives pesticide EECs in runoff and in spray drift, and develops risk quotients for 

non-listed and listed species of monocots and dicots inhabiting dry and semi-aquatic areas. 
41

The estimated exposure concentrations of trinexapac-ethyl for terrestrial plants are presented 

below (Table 12). The most protective ground and aerial application scenarios for each use 

were selected, based on information from the label (see Appendix H for sample output). 

Table 12. Terrestrial plant exposure concentration estimates for trinexapac-ethyl

Description Equation

EEC (lb ai/A)

Ground

Aerial/ 

Chemigation

Wheat, barley, oat, and triticale

1 app at 0.11 lb ai/A

Runoff to dry areas (A/I)*R 0.0055 0.0055

Runoff to semi-aquatic areas (A/I)*R*10 0.055 0.055

Spray drift A*D 0.0011 0.0055

Total for dry areas ((A/I)*R)+(A*D) 0.0066 0.011

Total for semi-aquatic areas ((A/I)*R*10)+(A*D) 0.0561 0.0605

Sugarcane

1 app at 0.31 lb ai/A

Runoff to dry areas (A/I)*R 0.0155 0.0155

Runoff to semi-aquatic areas (A/I)*R*10 0.155 0.155

Spray drift A*D 0.0031 0.0155

Total for dry areas ((A/I)*R)+(A*D) 0.0186 0.031

Total for semi-aquatic areas ((A/I)*R*10)+(A*D) 0.1581 0.1705

Grasses grown for seed

1 app at 0.5 lb ai/A

Runoff to dry areas (A/I)*R 0.025 0.025

Runoff to semi-aquatic areas (A/I)*R*10 0.25 0.25

Spray drift A*D 0.005 0.025

Total for dry areas ((A/I)*R)+(A*D) 0.03 0.05

Total for semi-aquatic areas ((A/I)*R*10)+(A*D) 0.255 0.275

Turf

1 app at 0.34 lb ai/A

Runoff to dry areas (A/I)*R 0.017 0.017

Runoff to semi-aquatic areas (A/I)*R*10 0.17 0.17

Spray drift A*D 0.0034 0.017

Total for dry areas ((A/I)*R)+(A*D) 0.0204 0.034

Total for semi-aquatic areas ((A/I)*R*10)+(A*D) 0.1734 0.187

Turf

1 app at 0.68 lb ai/A

Runoff to dry areas (A/I)*R 0.034 0.034

Runoff to semi-aquatic areas (A/I)*R*10 0.34 0.34

Spray drift A*D 0.0068 0.034

Total for dry areas ((A/I)*R)+(A*D) 0.0408 0.068

Total for semi-aquatic areas ((A/I)*R*10)+(A*D) 0.3468 0.374

Turf
42

Description Equation

EEC (lb ai/A)

Ground

Aerial/ 

Chemigation

1 apps at 1.36 lb ai/A

Runoff to dry areas (A/I)*R 0.068 0.068

Runoff to semi-aquatic areas (A/I)*R*10 0.68 0.68

Spray drift A*D 0.0136 0.068

Total for dry areas ((A/I)*R)+(A*D) 0.0816 0.136

Total for semi-aquatic areas ((A/I)*R*10)+(A*D) 0.6936 0.748

A = application rate

I = incorporation

R = runoff fraction

D = drift fraction
Chapter 3 Effects Characterization

43

Effects Characterization

The toxicity profile for trinexapac-ethyl is relatively complete. The DCI included an acute 

oral toxicity test conducted with a passerine species. The study was submitted and classified 

as “acceptable,” thus meeting the guideline requirements. Most notably, it provides the most 

sensitive endpoint for acute oral toxicity to birds.

Some additional information was available from the open literature. Several studies 

examined the effects of trinexapac-ethyl on fungi. Fungi endpoints are not normally required 

by the Agency and currently there are no endangered species of fungi. These studies are not 

included in this analysis, but they are listed in Appendix D. Several studies on grasses 

(monocots) with lower endpoints than those within Agency holdings were also available; 

however, two of these were non-definitive (greater than) values and the other one was related 

to root weight, which is not considered a reliable risk assessment endpoint because of the 

difficulty in maintaining consistency when measuring it. Consequently, none of the open 

literature studies were incorporated into the assessment. A list of the trinexapac-ethyl open 

literature studies that were screened as part of this assessment is provided in Appendix D.

There are several data gaps for trinexapac-ethyl. Estuarine/marine fish and invertebrate data 

are not available for chronic exposures to trinexapac-ethyl. The chronic value for freshwater 

fish was considered an appropriate surrogate for the chronic estuarine/marine data because 

freshwater fish were more sensitive on an acute basis. Estuarine/marine invertebrates were 

more sensitive on an acute basis than their freshwater counterparts, thus an acute-to-chronic 

ratio was used to predict a toxicity value. Data also are not available for the acute oral 

toxicity of trinexapac-ethyl to adult honeybees and its toxicity to larvae. These studies are 

recommended by the Pollinator White Paper (USEPA 2012) and are thus more recent 

requirements than the DCI. In the absence of these data, assumptions were drawn from the 

results of the analysis using the honeybee acute contact toxicity data.

Terrestrial Vertebrate Toxicology

Effects on Birds

The zebra finch study (MRID 48894501) yielded the most sensitive acute oral endpoint 

(LD50 = 813 mg ai/kg-bw) and the only acute definitive endpoint available for birds (Table 

13). The study produced an irregular dose response curve with mortalities at the top two 

treatment levels (2000 and 2500 mg ai/kg-bw) being lower than mortalities at the second and 

third treatment levels (500 and 1000 mg ai/kg-bw). Consequently, a conservative LD50 was 

calculated using just the first three treatment levels (500, 1000, and 1500 mg ai/kg-bw). A 

clear decrease in food consumption was observed in all of the treatment levels during the first 

48 hours after dosing; by 72 hours after the dosing, food consumption levels were 

approaching control levels. Other sub-lethal effects included piloerection, lethargy, and 

labored breathing, all of which occurred within 30 minutes of receiving the dose. The study 

indicates that trinexapac-ethyl is slightly toxic to passerine birds. 

Two dietary studies were available, one with the bobwhite quail and the other with the 

mallard duck (Table 13). Both yielded LC50s of >5200 mg ai/kg-diet (MRIDs 41563902, 

41563903). No sub-lethal effects were reported in either study.
Chapter 3 Effects Characterization

44

A bobwhite quail study yielded the most sensitive chronic toxicity value (Table 13). The 

most sensitive endpoint was the number of eggs set (25% reduction). No adverse effects on 

behavior or food consumption were observed. 

Effects on Mammals

The acute toxicity of trinexapac-ethyl was assessed in male and female rats. Female rats 

were found to be more sensitive than males. A number of sub-lethal effects were observed 

that included decreased activity, piloerection, and ataxia (see table for more detail). 

Trinexapac-ethyl is classified as “practically non-toxic” on an acute oral exposure basis to 

mammals (Table 13).

A two-generation rat study (MRID 43128604) was submitted by the registrant to ascertain 

the chronic exposure effects of trinexapac-ethyl (Table 13). Adults experienced reduced premating and gestation body weight as well as reduced body weight gain and food 

consumption. Decreased survival and body weight, and decreased body weight gain during 

lactation were observed in offspring. No adverse effects on reproductive performance were 

noted for either generation. 

Table 13. Summary of the measurement endpoints selected to evaluate risk for birds 

and mammals

Assessment

Endpoint

Measurement

Endpoint

Selected Measurement Endpoint Value and Source

Species Endpoint, Toxicity

and Effect(s)

Chemical / 

Source / 

Study 

Classification

Survival and 

Reproduction of 

Birds, Reptiles 

and Amphibians

Mortality: acute oral 

avian LD50

Zebra finch

(Taeniopygia 

guttata)

LD50 = 813 mg ai/kg-bw 

Mortality and decrease in food consumption

Trinexapac-ethyl 

technical grade, 

95.8% ai

MRID 48894501

Acceptable

Mortality: subacute 

avian LC50

Bobwhite quail 

(Colinus 

virginianus) 

LC50 > 5200 mg ai/kg-diet 

No effects

Trinexapac-ethyl 

technical grade, 

96.6% ai

MRID 41563902, 

Acceptable

Mortality: subacute 

avian LC50

Mallard duck 

(Anas 

platyrhynchos)

LC50 > 5200 mg ai/kg-diet 

No effects

Trinexapac-ethyl 

technical grade, 

96.6% ai

MRID 41563903

Acceptable
Chapter 3 Effects Characterization

45

Assessment

Endpoint

Measurement

Endpoint

Selected Measurement Endpoint Value and Source

Species Endpoint, Toxicity

and Effect(s)

Chemical / 

Source / 

Study 

Classification

Reproduction: 

chronic 

reproduction 

NOAEC

Bobwhite quail 

(Colinus 

virginianus)

NOAEC = 200 mg ai/kg-diet

LOAEC = 600 mg ai/kg-diet

The most sensitive parameter was a reduction 

in the proportion of eggs set.

Trinexapac-ethyl 

technical grade, 

96.6% ai

MRID 41869505

Acceptable

Survival and 

Reproduction of 

Mammals

Mortality: acute oral 

LD50

Rat (Rattus 

norvegicus)

Female LD50 = 4212 mg ai/kg-bw

Male LD50 = 4613 mg ai/kg-bw

Combined = 4458 mg ai/kg-bw

Decreased activity, ataxia, diarrhea, dilated 

pupils, epistaxis, hematuria, lacrimation, nasal 

discharge, piloerection, polyuria, ptosis, and 

salivation

Trinexapac-ethyl 

technical grade, 

96.9% ai

MRID 41563908

Acceptable

Reproduction: 

chronic 

reproduction 

NOAEC

Rat (Rattus 

norvegicus)

Male NOAEL = 594 mg ai/kg-diet 

Male LOAEL = 1212 mg ai/kg-diet

Female NOAEL = 751 mg ai/kg-diet

Female LOAEL = 1485 mg ai/kg-diet

(toxicity to parents and offspring)

Male NOAEL = 1212 mg ai/kg-diet

Female NOAEL = 1485 mg ai/kg-diet

(reproductive toxicity)

Trinexapac-ethyl 

technical grade, 

96.2% ai

MRID 43128604

Acceptable

Terrestrial Invertebrate Toxicology

There was one acute contact toxicity study for worker honeybees that resulted in an LD50 of 

47 μg ai/bee. No sub-lethal effects were reported and the toxicity value indicates that 

trinexapac-ethyl is practically non-toxic to honeybees (Table 14). Neither acute oral toxicity 

data nor larval toxicity data were available.

Table 14. Summary of specific measurement endpoint values selected to evaluate risk 

for honeybees

Assessment

Endpoint

Measurement

Endpoint

Selected Measurement Endpoint Value and Source

Species Endpoint, Toxicity,

and Effect(s) (μg ai/bee)

Chemical / 

Source / 

Acute Contact 

Toxicity

Mortality: acute 

contact LD50

Honey Bee 

(Apis mellifera)

LD50 = 47

Mortality

Trinexapac-ethyl 

technical grade, 

96.2% ai

MRID 41563928

Acceptable
Chapter 3 Effects Characterization

46

Aquatic Vertebrate (Fish) Toxicology

Effects to Freshwater Fish and Aquatic-Phase Amphibians

Acute data from four fish species are available for trinexapac-ethyl (Table 15). The studies 

classify trinexapac-ethyl as practically non-toxic to slightly toxic for freshwater fish. The 

catfish (MRID 41869507) was the most sensitive warm water species that was tested with an 

LC50 of 35 mg ai/L. Sub-lethal observations included erratic swimming and loss of 

equilibrium. Sub-lethal effects were seen in carp (changes in pigmentation) (MRID 

41869506), and bluegill sunfish (immobilization and sluggish reaction) as well (MRID 

41563904) – the least sensitive of the warm water fish that were tested. The carp study was 

classified as supplemental because it was considered an unacceptable species for testing at 

the time the study evaluation occurred. For registration review risk assessments, the Agency 

accepts information from studies that are considered scientifically valid. Therefore, carp will 

be considered in this risk assessment.

The rainbow trout was the only cold water species that was tested and resulted in a 96-hour 

EC50 of 68 mg ai/L (MRID 41563905). Sub-lethal effects included immobilization, erratic 

swimming, and sluggish reaction to stimuli. 

Chronic data were available for the fathead minnow (Table 15). Chronic effects (based on 

growth) were seen at 0.41 mg ai/L. 

Effects to Estuarine-Marine Fish

The estuarine/marine fish (sheepshead minnow) study suggests that estuarine/marine fish are 

less sensitive to trinexapac-ethyl than freshwater fish (MRID 41869510). The study 

established a 96-hour LC50 of 180 mg ai/L. All fish exhibited erratic swimming behavior 

and many also had darkened pigmentation, loss of equilibrium, and lethargy (Table 15).

Chronic data were not available for estuarine/marine fish. In the absence of chronic toxicity 

data for estuarine/marine fish, a toxicity value could normally be estimated based on the 

assumption that the acute-to-chronic ratio for freshwater fish (species X) applies to 

estuarine/marine fish (species Y) also. The acute-to-chronic ratio is typically calculated as 

follows: 

Acutespecies X = Acutespecies Y

ChronicspeciesX ChronicspeciesY

Given that a complete set of acute-chronic data is not available for any freshwater fish 

species, a chronic value for the estuarine/marine sheepshead minnow was not estimated. 

Using toxicity data from two species would have introduced additional uncertainty into the 

estimated estuarine/marine chronic toxicity value. 

As an alternative to the acute-to-chronic ratio, toxicity data from freshwater fish was 

considered as a surrogate. The acute toxicity of the sheepshead minnow was 2.5 to 5 times 

less sensitive than the definitive acute toxicity values for freshwater fish (since the bluegill 

study is non-definitive, it is unknown if this species is similar or less sensitive than the 

sheepshead minnow), thus, the freshwater fish chronic NOAEC is considered a protective 
Chapter 3 Effects Characterization

47

surrogate in lieu of the estuarine/marine fish NOAEC. Furthermore, the sub-lethal effects 

observed in the acute estuarine/marine fish study were similar to those observed in 

freshwater fish studies.

Table 15. Summary of endpoints selected to evaluate risk for fish and amphibians

Assessment

Endpoint

Measurement

Endpoint

Selected Measurement Endpoint Value and Source

Species Endpoint, Toxicity,

and Effect(s) (mg ai/L)

Chemical/

Source /

Study

Classification

Survival and 

reproduction of 

freshwater fish

Acute mortality: 

most sensitive acute 

freshwater fish 96-

hour LC50

Catfish (Ictalurus 

punctatus)

LC50 = 35

Mortality, erratic swimming, 

loss of equilibrium

Trinexapac-ethyl technical 

grade, 92.2% ai

MRID 41869507

Acceptable

Carp (Cyprinus 

carpio)

LC50 = 57

Mortality, darkened 

pigmentation

Trinexapac-ethyl technical 

grade, 92.2% ai

MRID 41869506

Supplemental

Bluegill sunfish 

(Lepomis 

macrochirus)

EC50 > 130

Immobilization and sluggish 

reaction to stimuli

Trinexapac-ethyl technical 

grade, 96.6% ai

MRID 41563904

Acceptable

Rainbow trout 

(Oncorhynchus 

mykiss)

96-hour EC50 = 68

Mortality, immobilization, 

erratic swimming, sluggish 

reaction to stimuli

Trinexapac-ethyl technical 

grade, 96.6% ai

MRID 41563905

Acceptable

Chronic Early Life 

Stage:

most sensitive 

NOAEC

Fathead minnow 

(Pimphales 

promelas)

NOAEC = 0.41

LOAEC = 0.80

Growth reduction

Trinexapac-ethyl, technical 

grade, 92.2% ai

MRID 42081401

Acceptable

Survival and 

reproduction of 

estuarine/marine 

fish

Acute mortality: 

most sensitive acute 

estuarine/marine 

fish 96-hour LC50

Sheepshead 

minnow 

(Cyprinodon 

variegates)

96-hour LC50 = 180

Erratic swimming, loss of 

equilibrium, darkened 

pigmentation, lethargy

Trinexapac-ethyl technical 

grade, 92.2% ai

MRID 41869510

Acceptable

Chronic Early Life 

Stage: most 

sensitive NOAEC

N/A

Fathead minnow 

(Pimphales 

promelas) data used 

instead

NOAEC = 0.41 Trinexapac-ethyl, technical 

grade, 92.2% ai

MRID 42081401

Acceptable
Chapter 3 Effects Characterization

48

Aquatic Invertebrate Toxicology

Effects to Freshwater Invertebrates

One acute study with freshwater invertebrates is available for trinexapac-ethyl (Table 17). 

The waterflea study yielded a non-definitive EC50 value of >142.5 mg ai/L, indicating that 

trinexapac-ethyl is practically non-toxic to freshwater invertebrates (MRID 41563906). 

Immobilization occurred, but not at levels high enough to calculate an EC50. In addition, 

erratic swimming and floating on the surface of the water were observed.

A chronic waterflea study was conducted with trinexapac-ethyl and yielded a NOAEC of 2.4 

mg ai/L and a LOAEC of 5.1 mg ai/L, based on reductions in the length of adult waterfleas. 

Reproduction was also affected (decreased number of offspring per female), but at the 

highest dose level (43 mg ai/L).

Effects to Estuarine-Marine Invertebrates

Acute exposure studies on estuarine/marine invertebrates indicated that trinexapac-ethyl is 

slightly toxic to the eastern oyster (EC50 > 89 mg ai/L) (MRID 41869509). A definitive EC50

could not be determined because none of the treatment levels produced a 50 percent 

reduction in oyster shell growth; however, a 48 percent reduction in shell growth was 

observed at the highest treatment level (89 mg ai/L). No mortality was observed. 

Trinexapac-ethyl is moderately toxic to mysid shrimp (LC50 = 6.5 mg ai/L) (MRID 

41869508). Toxic effects were observed at all treatment levels (e.g., erratic swimming, 

darkened pigmentation, lethargy) (Table 17). 

In the absence of chronic toxicity data for estuarine/marine invertebrates, the ECOSAR 

approach was explored as a method to predict the chronic toxicity for the mysid shrimp 

(ECOSAR predictive software is available publically though the Epi SuiteTM v 4.0 

program6). To determine if ECOSAR was accurately predicting toxicity values, the 

predicted toxicity values were compared with the endpoints for which the Agency had data 

(Table 16). As shown in the table, ECOSAR did not perform particularly well for the 

endpoints with known data. Most notable is that the ECOSAR ester estuarine/marine 

invertebrate chronic value was much higher than the ECOSAR acute value; chronic toxicity 

should always be lower than acute toxicity. This may be an indication that the ECOSAR 

ester prediction is not reliable and that the vinyl/allyl ketone estimates are more appropriate. 

Taking a closer look at these, the predicted values are generally 19 to 39 times higher than 

the actual values (excluding the freshwater acute value because it is non-definitive). 

Consequently, the ECOSAR predictions are not considered reliable in this situation.

Table 16. Comparison of Actual Toxicity Data and ECOSAR Values

Actual (mg ai/L) ECOSAR Ester (mg ai/L) ECOSAR Vinyl/Allyl Ketone 

(mg ai/L)

Acute Chronic Acute Chronic Acute Chronic

Freshwater 

invertebrates

>145.5 2.4 108 81 317 46

Estuarine/ 

marine 

6.5 N/A 89 12096 256 39

 6 http://www.epa.gov/oppt/exposure/pubs/episuite.htm 
Chapter 3 Effects Characterization

49

invertebrates

A toxicity value also can be estimated based on the assumption that the acute-to-chronic ratio 

for freshwater invertebrates applies to estuarine/marine invertebrates. However, only nondefinitive acute data were available for the waterflea EC50 (>142.5 mg ai/L). Usually the 

uncertainty of a non-definitive value is considered too great to calculate an ACR; however 

this was the approach adopted because trinexapac-ethyl does not have any surrogates for 

which toxicity data could be taken and the ECOSAR estimate did not appear to be reliable. 

Acutedaphnid = Acutemysid

Chronicdaphnid Chronicmysid

142.5 = 6.5

2.4 Chronicmysid

Mysid NOAEC = 0.11 mg ai/L

Given that a non-definitive value was used, the estimated NOAEC represents an upper-bound 

value and is not conservative.
Chapter 3 Effects Characterization

50

Table 17. Summary of specific measurement endpoint values selected to evaluate risk 

for aquatic invertebrate assessment endpoints

Assessment

Endpoint

Measurement

Endpoint

Selected Measurement Endpoint Value and Source

Species Endpoint, Toxicity,

and Effect(s) (mg ai/L)

Chemical/

Source /

Study

Classification

Survival and 

reproduction of 

freshwater 

invertebrates

Acute mortality: 

most sensitive acute 

freshwater 

invertebrate 48-hour 

EC50

Waterflea (D. 

magna)

48-hour EC50 >145.5

Mortality, immobilization, floating at 

water surface, erratic swimming

Trinexapac-ethyl, 

technical grade, 

96.6% ai

MRID 47408410

Supplemental

Chronic effects: 

most sensitive 

NOAEC

Waterflea (D. 

magna)

NOAEC = 2.4

LOAEC = 5.1

Reductions in adult daphnid length

Trinexapac-ethyl, 

technical grade, 

93.8%

MRID 43128602

Acceptable

Survival and 

reproduction of 

estuarine/marine 

invertebrates

Acute mortality: 

most sensitive 

estuarine/marine 

invertebrate 96-hour 

EC50

Mysid shrimp 

(Americamysis 

bahia)

EC50 = 6.5

NOAEC < 3.4

Mortality, erratic swimming, darkened 

pigmentation, lethargy

Trinexapac-ethyl, 

technical grade, 

92.2%

MRID 41869508

Acceptable

Acute growth: most 

sensitive 

estuarine/marine 

invertebrate 96-hour 

EC50

Eastern oyster 

(Crassostrea 

virginianus)

EC50 >89

Shell growth

Trinexapac-ethyl, 

technical grade, 

92.2%

MRID 41869509

Acceptable

Chronic effects: 

most sensitive 

NOAEC

Mysid shrimp 

(Americamysis 

bahia)

Acute-to-Chronic Ratio

NOAEC = 0.11

Trinexapac-ethyl, 

technical grade, 5.07-

> 92.2% ai

MRIDs 41869508, 

43128602, 47408410

Supplemental

Terrestrial Plant Toxicology

Plant toxicity data were available for trinexapac-ethyl (Table 18). The seedling emergence 

data showed that monocots (oat EC25 = 0.301 lb ai/A) were less sensitive to trinexapac-ethyl 

than dicots (carrot EC25 = 0.22 lb ai/A). The NOAEC for both species was the same (0.094 

lb ai/A), but was based on plant height for monocots (oat and ryegrass) and dry weight for 

dicots (lettuce). The vegetative vigor study (MRID 41869531) indicated that monocots (oat 

EC25 = 0.294 lb ai/A; NOAEC 0.0425 lb ai/A, based on plant height) had similar sensitivity 

to trinexapac-ethyl as dicots (carrot EC25 = 0.267 lb ai/A; NOAEC 0.085 lb ai/A, based on 

dry weight).
Chapter 3 Effects Characterization

51

Table 18. Summary of endpoint values selected to evaluate risk for terrestrial plants

Assessment

Endpoint

Measurement

Endpoint

Selected Measurement Endpoint Value and Source

Species Endpoint, Toxicity,

and Effect(s) (lb ai/A)

Chemical/

Source /

Study

Classification

Effects to 

terrestrial plants

Vegetative vigor: 

dicot EC25 and 

NOAEC 

Carrot (Daucus 

carota)

EC25 = 0.267

NOAEC = 0.085

Dry weight.

Trinexapac-ethyl 

technical grade, 

93.7%

MRID 41869531

Acceptable

Vegetative vigor: 

monocot EC25 and 

NOAEC

Oat (Avena sativa) EC25 = 0.294

NOAEC = 0.0425

Plant height

Trinexapac-ethyl

technical grade, 

93.7%

MRID 41869531

Acceptable

Effects to 

terrestrial plants

Seedling 

emergence: dicot 

EC25 and NOAEC

Lettuce (Lactuca 

sativa)

EC25 = 0.22

NOAEC = 0.094

Plant dry weight

Trinexapac-ethyl 

technical grade, 

93.7% ai

MRID 41869529

Supplemental

Seedling 

emergence: 

monocot EC25 and 

NOAEC

Oat (Avena 

sativa), ryegrass 

(Lolium 

mlutiflorum)

EC25 = 0.301

NOAEC = 0.094

Plant height

Trinexapac-ethyl 

technical grade, 

93.7% ai

MRID 41869529

Supplemental

Aquatic Plant Toxicology

Among the non-vascular plants, freshwater blue-green algae (Anabaena flos-aquae) was the 

most sensitive to trinexapac-ethyl with an EC50 of 0.35 mg ai/L and a NOAEC of 0.11 mg 

ai/L (based on cell density) (MRID 41869535). Green algae (Pseudokirchneriella 

subcapitata) (MRID 48043713) was the second most sensitive non-vascular plant (EC50 = 14 

mg ai/L; NOAEC = 7.8 mg ai/L), based on a reduction in cell density and yield. Biomass 

and growth rate were also reduced compared to the control. The marine diatom 

(Skeletonema constatum) (MRID 41869533) was similar in its toxicity to green algae (EC50 = 

16 mg ai/L; NOAEC = 3.7 mg ai/L), based on cell growth. The freshwater diatom (Navicula 

pelliculosa) (MRID 41869534) was the least sensitive with an EC50 of 42 mg ai/L and a 

NOAEC of 6.2 mg ai/L, based on cell density (Table 19).

For aquatic vascular plants, a duckweed study resulted in an EC50 of 0.19 mg ai/L. The 

NOAEC and LOAEC (0.018 and 0.035 mg ai/L, respectively) were based on growth (Table 

19). 
Chapter 3 Effects Characterization

52

Table 19. Summary of endpoints selected to evaluate risk for aquatic plants

Assessment

Endpoint

Measurement

Endpoint

Selected Measurement Endpoint Value and Source

Species Endpoint, Toxicity,

and Effect(s) (μg ai/L)

Chemical/

Source /

Study

Classification

Survival and 

biomass of 

aquatic vascular 

and non-vascular 

plants

Non-vascular species: 

the most sensitive 

productivity EC50 

Blue-green algae 

(Anabaena flosaquae)

120-hour EC50 = 350

NOAEC = 110

Cell density

Trinexapac-ethyl 

technical grade, 

92.2% ai

MRID 41869535

Acceptable

Green algae 

(Pseudokirchneriella 

subcapitata)

96-hour EC50 = 14000

NOAEC = 7800

Cell density

Trinexapac-ethyl

technical grade, 

95.8% ai

MRID 48043713

Acceptable

Marine diatom 

(Skeletonema 

costatum)

120 hour EC50 = 16000

NOAEC = 3700

Cell density

Trinexapac-ethyl 

technical grade, 

92.2%

MRID 41869533

Acceptable

Freshwater diatom 

(Navicula 

pelliculosa)

120-hour EC50 = 42000

NOAEC = 6200

Cell density

Trinexapac-ethyl 

technical grade, 

92.2% ai

MRID 41869534

Acceptable

Vascular species: the 

most sensitive 

productivity EC50

Duckweed (Lemna 

gibba)

EC50 = 190

NOAEC = 18

Frond density

Trinexapac-ethyl 

technical grade, 

96.6% ai

MRID 42595303

Acceptable
53

Results: Risk Characterization

Risk Estimation

As described in the Trinexapac-Ethyl Work Plan, estimates of exposure and ecotoxicity of 

trinexapac-ethyl are integrated using standard risk quotient (RQ) methods to evaluate the 

potential for adverse ecological effects to non-target species. Risk quotient results for nontarget terrestrial and aquatic animals and plants are described in this section. Risk quotients

represent expected direct effects to organisms (i.e. effects from direct toxicity to trinexapacethyl exposure) in contrast to indirect effects to an organism resulting from a modification of 

a resource such as loss of their prey or habitat.

Direct Effects to Non-Target Terrestrial Vertebrates

DIRECT EFFECTS TO BIRDS, REPTILES, AND (LAND-PHASE) AMPHIBIANS

Acute Effects

For spray applications dose-based risk quotients ranged from <0.01 to 0.62 and some of the 

uses exceeded the LOC of 0.1 for listed species. Specifically, 20 g birds consuming short 

grass diets had RQs above the LOC for sugarcane and grasses grown for seed uses. Turf uses 

yielded RQs above the LOC for small and medium-sized birds on several food items (short 

grass, tall grass, broadleaf plants, arthropods). In addition, at the highest turf application rate 

(1.36 lb ai/A), small birds consuming short grass yielded RQs that exceeded the non-listed 

species LOC of 0.5.

For granular applications to turf, RQs ranged from <0.01 to 0.52. All of the uses exceeded 

the LOC of 0.1 for small (20 g) birds (Table 22).

Chronic dietary risk quotients ranged from 0.01 to 2.41 and exceeded the LOC of 1. More 

specifically, the two highest turf rates (0.68 and 1.36 lb ai/A) produced RQs that were above 

the LOC for short grass, tall grass, and broadleaf plants (Table 20). 

Table 20. Upper bound risk quotients for birds derived from T-REX

Risk Quotients 

Based

on Kenaga

Upper Bound EEC

Dose-Based RQs Chronic 

DietaryBased RQs

20 g 100 g 1000 g

Acute Acute Acute

Wheat, barley, oat, and triticale

1 app at 0.11 lb ai/A

Short grass 0.03 0.02 <0.01 0.13

Tall grass 0.02 0.01 <0.01 0.06

Broadleaf plants 0.02 0.01 <0.01 0.07

Fruits/pods 0.00 <0.01 <0.01 0.01

Arthropods 0.01 0.01 <0.01 0.05

Seeds <0.01 <0.01 <0.01 0.01

Sugarcane

1 app at 0.31 lb ai/A
54

Risk Quotients 

Based

on Kenaga

Upper Bound EEC

Dose-Based RQs Chronic 

DietaryBased RQs

20 g 100 g 1000 g

Acute Acute Acute

Short grass 0.10* 0.04 0.01 0.37

Tall grass 0.04 0.02 0.01 0.17

Broadleaf plants 0.05 0.02 0.01 0.21

Fruits/pods 0.01 <0.01 <0.01 0.02

Arthropods 0.04 0.02 0.01 0.15

Seeds <0.01 <0.01 <0.01 0.02

Grasses grown for seed

1 app at 0.5 lb ai/A

Short grass 0.15* 0.07 0.02 0.60

Tall grass 0.07 0.03 0.01 0.28

Broadleaf plants 0.09 0.04 0.01 0.34

Fruits/pods 0.01 <0.01 <0.01 0.04

Arthropods 0.06 0.03 0.01 0.24

Seeds <0.01 <0.01 <0.01 0.04

Turf

8 apps at 0.34 lb ai/A (4 weeks)

Short grass 0.24* 0.11* 0.03 0.95

Tall grass 0.11* 0.05 0.02 0.43

Broadleaf plants 0.14* 0.06 0.02 0.53

Fruits/pods 0.02 0.01 <0.01 0.06

Arthropods 0.10* 0.04 0.01 0.37

Seeds <0.01 <0.01 <0.01 0.06

Turf

4 apps at 0.68 lb ai/A (8 weeks)

Short grass 0.31* 0.14* 0.04 1.20***

Tall grass 0.14* 0.06 0.02 0.55

Broadleaf plants 0.17* 0.08 0.02 0.68

Fruits/pods 0.02 0.01 <0.01 0.08

Arthropods 0.12* 0.05 0.02 0.47

Seeds <0.01 <0.01 <0.01 0.08

Turf

4 apps at 1.36 lb ai/A (8 weeks)

Short grass 0.62** 0.28* 0.09 2.41***

Tall grass 0.28* 0.13* 0.04 1.10***

Broadleaf plants 0.35* 0.16* 0.05 1.35***

Fruits/pods 0.04 0.02 0.01 0.15

Arthropods 0.24* 0.11* 0.03 0.94

Seeds 0.01 <0.01 <0.01 0.15

Bold text indicates an LOC was exceeded.

* Exceeds the acute listed species LOC of 0.1
55

Risk Quotients 

Based

on Kenaga

Upper Bound EEC

Dose-Based RQs Chronic 

DietaryBased RQs

20 g 100 g 1000 g

Acute Acute Acute

**Exceeds or meets the acute non-listed species LOC of 0.5

***Exceeds the chronic LOC of 1

Direct Effects to Mammals 

Acute Effects

Acute dose-based risk quotients were calculated for the maximum application rates for all 

trinexapac-ethyl uses. Risk quotients ranged from <0.01 to 0.05 for spray applications and 

<0.01 to 0.07 for granular applications (Tables 21 and 22). None of the uses produced risk 

quotients that exceeded the acute listed species LOC of 0.1.

Chronic Effects

Chronic dose-based risk quotients ranged from <0.01 to 0.35 and dietary-based risk quotients 

ranged from <0.0 to 0.01 (Table 21). None of the risk quotients exceeded the LOC of 1.

Table 21. Dietary upper bound risk quotients for mammals 

Risk Quotients 

Based

on Kenaga

Upper Bound EEC

Dose-Based RQs Chronic 

DietaryBased RQs

15 g 35 g 1000 g

Acute Chronic Acute Chronic Acute Chronic

Wheat, barley, oat, and triticale

1 app at 0.11 lb ai/A

Short grass <0.01 0.02 <0.01 0.02 <0.01 0.01 <0.01

Tall grass <0.01 0.01 <0.01 0.01 <0.01 <0.01 <0.01

Broadleaf plants <0.01 0.01 <0.01 0.01 <0.01 <0.01 <0.01

Fruits/pods <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01

Arthropods <0.01 0.01 <0.01 0.01 <0.01 <0.01 <0.01

Seeds <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01

Sugarcane

1 app at 0.31 lb ai/A

Short grass 0.01 0.05 0.01 0.05 <0.01 0.02 0.01

Tall grass <0.01 0.02 <0.01 0.02 <0.01 0.01 <0.01

Broadleaf plants <0.01 0.03 <0.01 0.03 <0.01 0.01 <0.01

Fruits/pods <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01

Arthropods <0.01 0.02 <0.01 0.02 <0.01 0.01 <0.01

Seeds <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01

Grasses grown for seed

1 app at 0.5 lb ai/A

Short grass 0.01 0.09 0.01 0.07 0.01 0.04 0.01

Tall grass 0.01 0.04 <0.01 0.03 <0.01 0.02 <0.01

Broadleaf plants 0.01 0.05 0.01 0.04 <0.01 0.02 0.01
56

Risk Quotients 

Based

on Kenaga

Upper Bound EEC

Dose-Based RQs Chronic 

DietaryBased RQs

15 g 35 g 1000 g

Acute Chronic Acute Chronic Acute Chronic

Fruits/pods <0.01 0.01 <0.01 <0.01 <0.01 <0.01 <0.01

Arthropods <0.01 0.03 <0.01 0.03 <0.01 0.02 <0.01

Seeds <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01

Turf

8 apps at 0.34 lb ai/A (4 weeks)

Short grass 0.02 0.14 0.02 0.12 0.01 0.06 0.02

Tall grass 0.01 0.06 0.01 0.05 <0.01 0.03 0.01

Broadleaf plants 0.01 0.08 0.01 0.07 0.01 0.04 0.01

Fruits/pods <0.01 0.01 <0.01 0.01 <0.01 <0.01 <0.01

Arthropods 0.01 0.05 0.01 0.05 <0.01 0.02 0.01

Seeds <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01

Turf

4 apps at 0.68 lb ai/A (8 weeks)

Short grass 0.02 0.18 0.02 0.15 0.01 0.08 0.02

Tall grass 0.01 0.08 0.01 0.07 0.01 0.04 0.01

Broadleaf plants 0.01 0.10 0.01 0.08 0.01 0.05 0.01

Fruits/pods <0.01 0.01 <0.01 0.01 <0.01 0.01 <0.01

Arthropods 0.01 0.07 0.01 0.06 <0.01 0.03 0.01

Seeds <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01

Turf

4 apps at 1.36 lb ai/A (8 weeks)

Short grass 0.05 0.35 0.04 0.30 0.02 0.16 0.04

Tall grass 0.02 0.16 0.02 0.14 0.01 0.07 0.02

Broadleaf plants 0.03 0.20 0.02 0.17 0.01 0.09 0.02

Fruits/pods <0.01 0.02 <0.01 0.02 <0.01 0.01 <0.01

Arthropods 0.02 0.14 0.02 0.12 0.01 0.06 0.02

Seeds <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01

Table 22. Acute LD50/ft2 RQs for mammals, birds, reptiles, and amphibians for 

granular applications

Use, Formulation, Type of 

Application

RQs for Birds RQs for Mammals

20g 100g 1000g 15g 35g 1000g

Turf

7 apps at 0.35 lb ai/A (4 weeks) 0.21* 0.03 <0.01 0.03 0.01 <0.01

Turf

6 apps at 0.44 lb ai/A (4 weeks) 0.26* 0.04 <0.01 0.03 0.02 <0.01

Turf

3 apps at 0.88 lb ai/A (4 weeks) 0.52** 0.08 0.01 0.07 0.03 <0.01
57

Direct Effects to Non-Target Terrestrial Invertebrates

Acute contact RQs for the honeybee ranged from 0.03 to 0.35; none of the uses exceeded the 

honeybee LOC of 0.4 (USEPA 2012) (Table 23). However, all but the cereals uses exceeded 

the listed species interim LOC of 0.05. Acute dietary contact RQs could not be calculated 

because the acute contact toxicity data were non-definitive. See the Risk Description section 

for further characterization.

Table 23. Adult insect foliar spray risk quotient values

Use RQ

Wheat, barley, oat, and triticale

1 app at 0.11 lb ai/A 0.03

Sugarcane

1 app at 0.31 lb ai/A 0.08*

Grasses grown for seed

1 app at 0.5 lb ai/A 0.13*

Turf

8 apps at 0.34 lb ai/A (4 weeks) 0.09*

Turf

4 apps at 0.68 lb ai/A (8 weeks) 0.17*

Turf

4 apps at 1.36 lb ai/A (8 weeks) 0.35*

*Exceeds the listed species interim LOC of 0.05

Direct Effects to Terrestrial and Wetland/Riparian Plants

TerrPlant was used to model potential runoff and spray drift effects from the different 

trinexapac-ethyl uses (Table 24). The maximum application rate for each crop was used to 

calculate risk quotients for semi-aquatic and upland terrestrial plants, as well as risks from 

spray drift. 

The wheat, barley, oat, and triticale scenario (1 app at 0.11 lb ai/A) was the only one that did 

not yield risk quotients that exceeded the LOC of 1. The sugarcane and lowest turf 

application rate (0.34 lb ai/A) produced RQs above the LOC for semi-aquatic listed and nonlisted monocots and dicots. The turf scenario at 0.68 lb ai/A had RQs above the LOC for all 

semi-aquatic plants (listed and non-listed) for both chemigation and ground applications. 

Finally, the highest turf application rate (1.36 lb ai/A) identified RQs above the LOC for all 

semi-aquatic plants and chemigation applications to listed plants. At this rate, the spray drift 

RQ also exceeded the LOC for chemigation applications to listed monocots. 

Table 24. Summary of risk quotient values for plants in dry and semi-aquatic areas 

exposed to trinexapac-ethyl through runoff and spray drift

Plant Listed Dry Semi-Aquatic Spray Drift
58

Type Status Ground Aerial/

Chem

Ground Aerial/ 

Chem

Ground Aerial/ 

Chem

Wheat, barley, oat, and triticale

1 app at 0.11 lb ai/A

Monocot non-listed <0.1 <0.1 0.19 0.20 <0.1 <0.1

Monocot listed <0.1 0.12 0.60 0.64 <0.1 0.13

Dicot non-listed <0.1 <0.1 0.26 0.28 <0.1 <0.1

Dicot listed <0.1 0.12 0.60 0.64 <0.1 <0.1

Sugarcane

1 app at 0.31 lb ai/A

Monocot non-listed <0.1 0.10 0.53 0.57 <0.1 <0.1

Monocot listed 0.20 0.33 1.68* 1.81* <0.1 0.36

Dicot non-listed <0.1 0.14 0.72 0.78 <0.1 <0.1

Dicot listed 0.20 0.33 1.68* 1.81* <0.1 0.16

Grasses grown for seed

1 app at 0.5 lb ai/A

Monocot non-listed <0.1 0.17 0.85 0.91 <0.1 <0.1

Monocot listed 0.32 0.53 2.71* 2.93* 0.12 0.59

Dicot non-listed 0.14 0.23 1.16* 1.25* <0.1 0.11

Dicot listed 0.32 0.53 2.71* 2.93* <0.1 0.27

Turf

1 app at 0.34 lb ai/A

Monocot non-listed <0.1 0.11 0.58 0.62 <0.1 <0.1

Monocot listed 0.22 0.36 1.84* 1.99* <0.1 0.40

Dicot non-listed <0.1 0.15 0.79 0.85 <0.1 <0.1

Dicot listed 0.22 0.36 1.84* 1.99* <0.1 0.18

Turf

1 app at 0.68 lb ai/A

Monocot non-listed 0.14 0.23 1.15* 1.24* <0.1 0.12

Monocot listed 0.43 0.72 3.69* 3.98* 0.16 0.80

Dicot non-listed 0.19 0.31 1.58* 1.70* <0.1 0.15

Dicot listed 0.43 0.72 3.69* 3.98* <0.1 0.36

Turf

1 app at 1.36 lb ai/A

Monocot non-listed 0.27 0.45 2.30* 2.49* <0.1 0.23

Monocot listed 0.87 1.45* 7.38* 7.96* 0.32 1.60*

Dicot non-listed 0.37 0.62 3.15* 3.40* <0.1 0.31

Dicot listed 0.87 1.45* 7.38* 7.96* 0.14 0.72

*Exceeds LOC of 1.
59

Direct Effects to Freshwater Fish (Amphibians), Invertebrates and EstuarineMarine Fish (Amphibians) and Invertebrates, and Aquatic Plants

Risk quotients for aquatic organisms are calculated using aquatic EECs derived as described 

in the exposure analysis using PRZM/EXAMS in conjunction with selected acute and 

chronic fish, aquatic invertebrate, and aquatic plant toxicity values. The calculated risk 

quotients are based on total toxic residue exposure from the parent trinexapac-ethyl and its 

major degradates for the aquatic environment.

Freshwater Fish and Aquatic-Phase Amphibians – Acute Risk

For freshwater fish (surrogate for aquatic-phase amphibians), acute risk quotients were all 

<0.01 and did not exceed the listed species acute LOC of 0.05 for any registered trinexapacethyl uses (Table 25). 

Freshwater Fish and Aquatic-Phase Amphibians – Chronic Risk

For freshwater fish (surrogate for aquatic-phase amphibians), chronic risk quotients were all 

<0.01 and did not exceed the chronic LOC of 1 (Table 25).

Estuarine/Marine Fish – Acute Risk

For estuarine/marine fish, acute risk quotients were all below 0.01 and did not exceed the 

listed species acute LOC of 0.05 for any registered trinexapac-ethyl uses (Table 25). 

Estuarine/Marine Fish – Chronic Risk

For estuarine/marine fish, chronic risk quotients were <0.01 and did not exceed the chronic 

LOC of 1 (Table 25). 

Table 25. Acute and chronic risks from trinexapac-ethyl to freshwater fish and 

estuarine/marine fish

Use (Scenario)

Ariel (A) or 

Ground (G) 

or 

Chemigation 

(C)

1-in-10-year Aquatic EECs (μg/L)

Freshwater 

Fish Acute 

RQ (Peak 

EEC/LC50) 

LC50 = 35000

μg ai/L

Freshwater Fish 

Chronic RQ 

(60-Day EEC/ 

NOAEC) 

NOAEC = 410 

μg ai/L

Estuarine / 

Marine Fish 

Acute RQ 

(Peak 

EEC/LC50) 

LC50 = 180000

μg ai/L

Estuarine / 

Marine Fish 

Chronic RQ 

(60-Day EEC/ 

NOAEC) 

NOAEC = 

410 μg ai/L

Cereals – 1 app at 0.11 lb ai/A

ND Wheat

(June 21 – foliar) A <0.01 <0.01 <0.01 <0.01

ND Wheat

(June 21 – foliar) G <0.01 <0.01 <0.01 <0.01

ND Wheat

(June 21 - chemigation) C <0.01 <0.01 <0.01 <0.01

Sugarcane – 1 app at 0.31 lb ai/A

FL Sugarcane

(December 03 – foliar) A <0.01 <0.01 <0.01 <0.01

FL Sugarcane

(December 03 – foliar) G <0.01 <0.01 <0.01 <0.01
60

Use (Scenario)

Ariel (A) or 

Ground (G) 

or 

Chemigation 

(C)

1-in-10-year Aquatic EECs (μg/L)

Freshwater 

Fish Acute 

RQ (Peak 

EEC/LC50) 

LC50 = 35000

μg ai/L

Freshwater Fish 

Chronic RQ 

(60-Day EEC/ 

NOAEC) 

NOAEC = 410 

μg ai/L

Estuarine / 

Marine Fish 

Acute RQ 

(Peak 

EEC/LC50) 

LC50 = 180000

μg ai/L

Estuarine / 

Marine Fish 

Chronic RQ 

(60-Day EEC/ 

NOAEC) 

NOAEC = 

410 μg ai/L

FL Sugarcane

(December 03 – chem.) C <0.01 <0.01 <0.01 <0.01

LA Sugarcane

(December 03 – foliar) A <0.01 <0.01 <0.01 <0.01

LA Sugarcane

(November 26 – foliar) A <0.01 <0.01 <0.01 <0.01

LA Sugarcane

(November 19 – foliar) A <0.01 <0.01 <0.01 <0.01

LA Sugarcane

(November 12 – foliar) A <0.01 <0.01 <0.01 <0.01

LA Sugarcane

(November 5 – foliar) A <0.01 <0.01 <0.01 <0.01

LA Sugarcane

(November 1 – foliar) A <0.01 <0.01 <0.01 <0.01

LA Sugarcane

(December 03 – foliar) G <0.01 <0.01 <0.01 <0.01

LA Sugarcane

(December 03 – chem.) C <0.01 <0.01 <0.01 <0.01

Grasses grown for seed – 1 app at 0.5 lb ai/A

FL Turf

(February 15 – foliar) A <0.01 <0.01 <0.01 <0.01

FL Turf

(February 15 – foliar) G <0.01 <0.01 <0.01 <0.01

FL Turf

(February 15 – chem.) C <0.01 <0.01 <0.01 <0.01

PA Turf

(April 15 – foliar) A <0.01 <0.01 <0.01 <0.01

PA Turf

(April 15 – foliar) G <0.01 <0.01 <0.01 <0.01

PA Turf

(April 15 – chem.) C <0.01 <0.01 <0.01 <0.01

Turf – 8 apps at 0.34 lb ai/A (28 days)

FL Turf

(February 1 – foliar) G <0.01 <0.01 <0.01 <0.01

FL Turf

(February 1 – chem.) C <0.01 <0.01 <0.01 <0.01

PA Turf

(April 01 – foliar) G <0.01 <0.01 <0.01 <0.01
61

Use (Scenario)

Ariel (A) or 

Ground (G) 

or 

Chemigation 

(C)

1-in-10-year Aquatic EECs (μg/L)

Freshwater 

Fish Acute 

RQ (Peak 

EEC/LC50) 

LC50 = 35000

μg ai/L

Freshwater Fish 

Chronic RQ 

(60-Day EEC/ 

NOAEC) 

NOAEC = 410 

μg ai/L

Estuarine / 

Marine Fish 

Acute RQ 

(Peak 

EEC/LC50) 

LC50 = 180000

μg ai/L

Estuarine / 

Marine Fish 

Chronic RQ 

(60-Day EEC/ 

NOAEC) 

NOAEC = 

410 μg ai/L

PA Turf

(April 01 – chem.) C <0.01 <0.01 <0.01 <0.01

Turf – 4 apps at 0.68 lb ai/A (56 days)

FL Turf

(February 1 – foliar) G <0.01 <0.01 <0.01 <0.01

FL Turf

(February 1 – chem.) C <0.01 <0.01 <0.01 <0.01

PA Turf

(April 01 – foliar) G <0.01 <0.01 <0.01 <0.01

PA Turf

(April 01 – chem.) C <0.01 <0.01 <0.01 <0.01

Turf – 2 apps at 1.36 lb ai/A (56 days)

FL Turf

(February 1 – foliar) G <0.01 <0.01 <0.01 <0.01

FL Turf

(February 1 – chem.) C <0.01 <0.01 <0.01 <0.01

PA Turf

(April 01 – foliar) G <0.01 <0.01 <0.01 <0.01

PA Turf

(April 01 – chem.) C <0.01 <0.01 <0.01 <0.01

Freshwater Invertebrates – Acute Risk

Risk quotients could not be calculated for freshwater invertebrates because the toxicity value 

was non-definitive. See the risk characterization for a description of the expected risks. 

Freshwater Invertebrates – Chronic Risk

For freshwater invertebrates, the chronic risk quotients were all <0.01. None of them 

exceeded the chronic LOC (1) for any registered use of trinexapac-ethyl (Table 26).

Estuarine/Marine Invertebrates – Acute Risk

For estuarine/marine invertebrates, the acute risk quotients were all below 0.01. None of the 

uses exceeded the acute LOC of 0.05 (Table 26).

Estuarine/Marine Invertebrates – Chronic Risk

For estuarine/marine invertebrates, the chronic risk quotients ranged from <0.01 to 0.04. 

None of them exceeded the chronic LOC (1) for any registered use of trinexapac-ethyl (Table 

26).
62

Table 26. Acute and chronic risks from trinexapac-ethyl to freshwater and 

estuarine/marine invertebrates

Use (Scenario)

Ariel (A) or 

Ground (G) 

or 

Chemigation 

(C)

1-in-10-year Aquatic EECs (μg/L)

Freshwater 

Invert Chronic 

RQ (21-Day 

EEC/ NOAEC) 

NOAEC = 2400 

μg ai/L

Estuarine / 

Marine Invert

Acute RQ 

(Peak 

EEC/LC50) 

LC50 = 6500 μg 

ai/L

Estuarine / 

Marine Invert 

Chronic RQ 

(21-Day EEC/ 

NOAEC) 

NOAEC = 110 

μg ai/L

Cereals – 1 app at 0.11 lb ai/A

ND Wheat

(June 21 – foliar) A <0.01 <0.01 <0.01

ND Wheat

(June 21 – foliar) G <0.01 <0.01 0.01

ND Wheat

(June 21 - chemigation) C <0.01 <0.01 0.01

Sugarcane – 1 app at 0.31 lb ai/A

FL Sugarcane

(December 03 – foliar) A <0.01 <0.01 0.02

FL Sugarcane

(December 03 – foliar) G <0.01 <0.01 0.02

FL Sugarcane

(December 03 – chem.) C <0.01 <0.01 0.02

LA Sugarcane

(December 03 – foliar) A <0.01 <0.01 0.05

LA Sugarcane

(November 26 – foliar) A <0.01 <0.01 0.03

LA Sugarcane

(November 19 – foliar) A <0.01 <0.01 0.03

LA Sugarcane

(November 12 – foliar) A <0.01 <0.01 0.03

LA Sugarcane

(November 5 – foliar) A <0.01 <0.01 0.03

LA Sugarcane

(November 1 – foliar) A <0.01 <0.01 0.02

LA Sugarcane

(December 03 – foliar) G <0.01 <0.01 0.04

LA Sugarcane

(December 03 – chem.) C <0.01 <0.01 0.04

Grasses grown for seed – 1 app at 0.5 lb ai/A

FL Turf

(February 15 – foliar) A <0.01 <0.01 0.01

FL Turf

(February 15 – foliar) G <0.01 <0.01 <0.01
63

Use (Scenario)

Ariel (A) or 

Ground (G) 

or 

Chemigation 

(C)

1-in-10-year Aquatic EECs (μg/L)

Freshwater 

Invert Chronic 

RQ (21-Day 

EEC/ NOAEC) 

NOAEC = 2400 

μg ai/L

Estuarine / 

Marine Invert

Acute RQ 

(Peak 

EEC/LC50) 

LC50 = 6500 μg 

ai/L

Estuarine / 

Marine Invert 

Chronic RQ 

(21-Day EEC/ 

NOAEC) 

NOAEC = 110 

μg ai/L

FL Turf

(February 15 – chem.) C <0.01 <0.01 <0.01

PA Turf

(April 15 – foliar) A <0.01 <0.01 0.01

PA Turf

(April 15 – foliar) G <0.01 <0.01 <0.01

PA Turf

(April 15 – chem.) C <0.01 <0.01 <0.01

Turf – 8 apps at 0.34 lb ai/A (28 days)

FL Turf

(February 1 – foliar) G <0.01 <0.01 <0.01

FL Turf

(February 1 – chem.) C <0.01 <0.01 <0.01

PA Turf

(April 01 – foliar) G <0.01 <0.01 0.02

PA Turf

(April 01 – chem.) C <0.01 <0.01 <0.01

Turf – 4 apps at 0.68 lb ai/A (56 days)

FL Turf

(February 1 – foliar) G <0.01 <0.01 0.01

FL Turf

(February 1 – chem.) C <0.01 <0.01 <0.01

PA Turf

(April 01 – foliar) G <0.01 <0.01 0.03

PA Turf

(April 01 – chem.) C <0.01 <0.01 0.02

Turf – 2 apps at 1.36 lb ai/A (56 days)

FL Turf

(February 1 – foliar) G <0.01 <0.01 0.03

FL Turf

(February 1 – chem.) C <0.01 <0.01 0.01

PA Turf

(April 01 – foliar) G <0.01 <0.01 0.04

PA Turf

(April 01 – chem.) C <0.01 <0.01 0.03

Aquatic Vascular and Non-vascular Plants 
64

Aquatic vascular plant risk quotients ranged from <0.01 to 0.38. Aquatic non-vascular plant 

risk quotients ranged from <0.01 to 0.06. None of the aquatic plant risk quotients exceeded 

the LOC of 1 for any registered use of trinexapac-ethyl (Table 27).

Table 27. Risks from trinexapac-ethyl to aquatic vascular and non-vascular plants

Use (Scenario)

Ariel (A) or 

Ground (G) 

or 

Chemigation 

(C)

1-in-10-year Aquatic EECs (μg/L)

Non-Listed 

Non-vascular 

Aquatic Plant 

RQ (Peak 

EEC/EC50) 

LC50 = 350 μg 

ai/L

Listed Nonvascular 

Aquatic Plant 

RQ (Peak EEC/ 

NOAEC) 

NOAEC = 110 

μg ai/L

Non-Listed 

Vascular 

Aquatic Plant

RQ (Peak 

EEC/EC50) 

LC50 = 190 μg 

ai/L

Listed 

Vascular 

Aquatic Plant

RQ (Peak

EEC/ 

NOAEC) 

NOAEC = 18

μg ai/L

Cereals – 1 app at 0.11 lb ai/A

ND Wheat

(June 21 – foliar) A <0.01 <0.01 <0.01 0.02

ND Wheat

(June 21 – foliar) G <0.01 <0.01 <0.01 0.01

ND Wheat

(June 21 - chemigation) C <0.01 <0.01 <0.01 0.01

Sugarcane – 1 app at 0.31 lb ai/A

FL Sugarcane

(December 03 – foliar) A <0.01 0.03 0.02 0.18

FL Sugarcane

(December 03 – foliar) G <0.01 0.03 0.02 0.17

FL Sugarcane

(December 03 – chem.) C <0.01 0.03 0.02 0.16

LA Sugarcane

(December 03 – foliar) A 0.02 0.06 0.03 0.37

LA Sugarcane

(November 26 – foliar) A 0.01 0.04 0.02 0.26

LA Sugarcane

(November 19 – foliar) A 0.01 0.04 0.02 0.24

LA Sugarcane

(November 12 – foliar) A 0.01 0.03 0.02 0.21

LA Sugarcane

(November 5 – foliar) A 0.01 0.04 0.02 0.23

LA Sugarcane

(November 1 – foliar) A <0.01 0.03 0.02 0.19

LA Sugarcane

(December 03 – foliar) G 0.02 0.06 0.03 0.35

LA Sugarcane

(December 03 – chem.) C 0.02 0.06 0.03 0.34

Grasses grown for seed – 1 app at 0.5 lb ai/A
65

Use (Scenario)

Ariel (A) or 

Ground (G) 

or 

Chemigation 

(C)

1-in-10-year Aquatic EECs (μg/L)

Non-Listed 

Non-vascular 

Aquatic Plant 

RQ (Peak 

EEC/EC50) 

LC50 = 350 μg 

ai/L

Listed Nonvascular 

Aquatic Plant 

RQ (Peak EEC/ 

NOAEC) 

NOAEC = 110 

μg ai/L

Non-Listed 

Vascular 

Aquatic Plant

RQ (Peak 

EEC/EC50) 

LC50 = 190 μg 

ai/L

Listed 

Vascular 

Aquatic Plant

RQ (Peak

EEC/ 

NOAEC) 

NOAEC = 18

μg ai/L

FL Turf

(February 15 – foliar) A <0.01 0.01 <0.01 0.08

FL Turf

(February 15 – foliar) G <0.01 <0.01 <0.01 0.02

FL Turf

(February 15 – chem.) C <0.01 <0.01 <0.01 <0.01

PA Turf

(April 15 – foliar) A <0.01 0.01 <0.01 0.08

PA Turf

(April 15 – foliar) G <0.01 <0.01 <0.01 0.03

PA Turf

(April 15 – chem.) C <0.01 <0.01 <0.01 0.02

Turf – 8 apps at 0.34 lb ai/A (28 days)

FL Turf

(February 1 – foliar) G <0.01 0.01 <0.01 0.09

FL Turf

(February 1 – chem.) C <0.01 <0.01 <0.01 0.04

PA Turf

(April 01 – foliar) G <0.01 0.03 0.01 0.16

PA Turf

(April 01 – chem.) C <0.01 0.01 <0.01 0.07

Turf – 4 apps at 0.68 lb ai/A (56 days)

FL Turf

(February 1 – foliar) G <0.01 0.02 0.01 0.24

FL Turf

(February 1 – chem.) C <0.01 <0.01 <0.01 0.05

PA Turf

(April 01 – foliar) G 0.01 0.04 0.02 0.25

PA Turf

(April 01 – chem.) C <0.01 0.02 0.01 0.13

Turf – 2 apps at 1.36 lb ai/A (56 days)

FL Turf

(February 1 – foliar) G 0.01 0.04 0.01 0.24

FL Turf

(February 1 – chem.) C <0.01 0.01 <0.01 0.09

PA Turf

(April 01 – foliar) G 0.02 0.06 0.04 0.38
66

Use (Scenario)

Ariel (A) or 

Ground (G) 

or 

Chemigation 

(C)

1-in-10-year Aquatic EECs (μg/L)

Non-Listed 

Non-vascular 

Aquatic Plant 

RQ (Peak 

EEC/EC50) 

LC50 = 350 μg 

ai/L

Listed Nonvascular 

Aquatic Plant 

RQ (Peak EEC/ 

NOAEC) 

NOAEC = 110 

μg ai/L

Non-Listed 

Vascular 

Aquatic Plant

RQ (Peak 

EEC/EC50) 

LC50 = 190 μg 

ai/L

Listed 

Vascular 

Aquatic Plant

RQ (Peak

EEC/ 

NOAEC) 

NOAEC = 18

μg ai/L

PA Turf

(April 01 – chem.) C 0.01 0.04 0.02 0.21

Probit Slope Response Analysis of LOC Values and Acute RQ Values

As part of the risk estimation, the probability of mortality associated with the listed acute 

LOC values is estimated along with the probability of acute mortality occurring if exposure 

at the EEC actually occurs. The probability of mortality calculations are based on the probit 

slope dose-response relationship. The probability of mortality for an exposed individual is 

calculated using an Excel spreadsheet tool IECV1.1(Individual Effect Chance Model Version 

1.1) developed by EFED of the U.S. EPA, OPP, Environmental Fate and Effects Division 

(June 22, 2004).

The model provides the option of inserting taxa-specific probit slopes and confidence 

intervals. If specific information is not available, the model uses a default value of 4.5 for 

the probit slope and 2 and 9 for the upper and lower 95% confidence interval bounds. For 

trinexapac-ethyl, taxa-specific data were only available for terrestrial invertebrates; default 

values were used for other taxonomic groups. 

Probabilities of mortality were only calculated for scenarios where the risk quotient exceeded 

the acute listed species LOC. For trinexapac-ethyl, there were only two groups that met this 

criterion – birds and terrestrial invertebrates. The highest RQ from each scenario was

modeled (Table 28).

Table 28. Odds of mortality for a bird or terrestrial invertebrate for trinexapac-ethyl

RQ Slope 95% Confidence 

Interval

Odds 

(1 in...)

Birds 

(sugarcane)

0.10 4.5 2, 9 294,000

Birds

(grasses grown for seed)

0.15 4.5 2, 9 9560

Birds

(turf at 0.34 lb ai/A)

0.24 4.5 2, 9 378

Birds

(turf at 0.68 lb ai/A)

0.31 4.5 2, 9 90

Birds

(turf at 1.36 lb ai/A)

0.62 4.5 2, 9 6

Terrestrial invertebrates

(sugarcane)

0.08 2.43 1.77, 3.09 260
67

RQ Slope 95% Confidence 

Interval

Odds 

(1 in...)

Terrestrial invertebrates

(grasses grown for seed)

0.13 2.43 1.77, 3.09 64

Terrestrial invertebrates

(turf at 0.34 lb ai/A)

0.09 2.43 1.77, 3.09 181

Terrestrial invertebrates

(turf 0.68 lb ai/A)

0.17 2.43 1.77, 3.09 33

Terrestrial invertebrates

(turf at 1.36 lb ai/A)

0.35 2.43 1.77, 3.09 7

Risk Description

The following risk description explains the overall direct effect conclusions regarding the 

potential ecological risk from the various uses of trinexapac-ethyl. The risk conclusions take 

into consideration all lines of evidence, such as the risk estimates (risk quotient results); 

information on the odds of mortality for the acute risk quotient values; comparisons of nondefinitive endpoints (i.e., limit tests) to EECs; information such as monitoring data, field 

studies, and incident data that may provide additional insights into the likelihood of 

exposure; and other factors that modify the likelihood of exposure such as timing of 

application, overlap of area affected and the degree of effect with the presence/absence of 

taxa, species sensitivity distribution, and presence/absence of dietary items.

 DIRECT EFFECTS TO TERRESTRIAL BIRDS, REPTILES, AND AMPHIBIANS

Acute Risk

Acute dose-based RQs indicated the potential for direct effects to listed species of birds 

(surrogate for reptiles, and land-phase amphibians) for the foliar sugarcane, grasses grown 

for seed, and turf uses (Table 30). There is a 1 in 294,000 (sugarcane), 1 in 9560 (grasses 

grown for seed), 1 in 378 (turf at 0.34 lb ai/A), 1 in 90 (turf at 0.68 lb ai/A), and 1 in 6 (turf 

at 1.36 lb ai/A) chance of individual mortality by these uses. More specifically, small (20 g 

birds) consuming diets of short grass were at risk for all of these uses. Turf scenarios at rates 

of 0.68 lb ai/A and higher triggered concerns for small and medium (100 g birds) on 

additional food items (tall grass, broadleaf plants, and arthropods). Finally, at the highest turf 

application rate (1.36 lb ai/A), small non-listed species of birds consuming short grass diets 

were also affected. Granular applications to turf also were flagged to cause adverse direct 

effects to birds. Thus, there is a potential for direct risk concerns for acute exposure of listed 

and non-listed birds, reptiles, and land-phase amphibians from trinexapac-ethyl for the 

sugarcane, grasses grown for seed, and turf uses. 

Buffers may be used to mitigate risk concerns that are the result of spray drift. To determine 

terrestrial habitats of concern from trinexapac-ethyl exposures through spray drift, it is 

necessary to estimate the distance that spray applications can drift from the treated area and 

still be present at concentrations that exceed levels of concern. Ground applications of 

trinexapac-ethyl granular formulations are expected to result in negligible drift. For the 

flowable uses, a quantitative analysis of spray drift distances was completed with AgDRIFT 

(v. 2.11) using default inputs for ground applications (i.e., high boom, ASAE droplet size 

distribution = Very Fine to Fine, 90th data percentile) and aerial applications (i.e., ASAE 
68

Very Fine to Fine). 

The results indicate that buffers for the sugarcane and grasses grown for seed uses would 

need to be a maximum of 3.28 ft around listed species habitat to mitigate acute effects to 

birds, reptiles, and terrestrial-phase amphibians. The turf uses would require larger buffers –

6.56 to 19.68 ft, depending on the application rate (Table 29).

Table 29. Avian, reptile, and terrestrial-phase amphibian Buffers for trinexapac-ethyl

Calculated with AgDRIFT

Use Single Application Rate (lb ai/A) Fraction of Applied Buffer Distance (ft)

Sugarcane (ground) 0.31 1 3.28

Sugarcane (aerial) 0.31 1 0

Grasses grown for seed 

(ground) 0.5 0.67 3.28

Grasses grown for seed 

(aerial) 0.5 0.67 0

Turf (ground) 0.34 0.42 6.56

Turf (ground) 0.68 0.32 9.84

Turf (ground) 1.36 0.16 19.68
69

Table 30 Trinexapac-ethyl uses that exceeded the acute dose-based LOC (0.1) for birds

Use Dose-based RQs

Short grass Tall grass Broadleaf plants Arthropods

20 g 100 g 1000 g 20 g 100 g 1000 g 20 g 100 g 1000 g 20 g 100 g 1000 g

Sugarcane Yes No No No No No No No No No No No

Grasses grown for seed Yes No No No No No No No No No No No

Turf (0.34 lb ai/A) Yes Yes No Yes No No Yes No No Yes No No

Turf (0.68 lb ai/A) Yes Yes No Yes No No Yes No No Yes No No

Turf (1.36 lb ai/A) Yes Yes No Yes Yes No Yes Yes No Yes Yes No
70

Chronic Risk

Risk quotients were calculated for dietary-based chronic risks and several exceeded the LOC 

of 1. Specifically, the two highest turf rates (0.68 and 1.36 lb ai/A) yielded RQs above the 

LOC for short grass, tall grass, and broadleaf plants. Consequently, direct effects to listed 

and non-listed avian, reptile, and terrestrial-phase amphibian species are possible. 

The SIP model identified drinking water as a potential exposure pathway for both acute and 

chronic risks for birds. Before the registration review risk assessment is finalized, the input 

for the expected concentration in water will be re-visited. Currently, it is based on the 

conservative assumption that the concentration in drinking water is equal to the solubility 

limit of trinexapac-ethyl. This is likely an overestimation and the true concentration would 

be much lower.

Summary of Risks from Direct Effects

A summary of the potential for acute and chronic risks to birds (surrogates for reptiles and 

land-phase amphibians) is listed below:

• There is a potential for acute risk concerns to listed and non-listed birds (surrogates 

for reptiles and land-phase amphibians) for sugarcane, grasses grown for seed, and 

turf uses, based on RQs exceeding the LOC.

• There is a potential for chronic risk concerns to listed and non-listed birds (reptiles 

and land-phase amphibians) for some turf uses, based on RQs exceeding the LOC (1). 

• There is a potential for acute and chronic risk concerns to birds, based on the drinking 

water exposure pathway.

DIRECT EFFECTS TO TERRESTRIAL MAMMALS

Acute Risk

Risk quotients were calculated for dietary and dose-based acute exposures. None of the 

trinexapac-ethyl uses exceeded the LOC of 0.1, for listed species. Therefore, acute direct 

effects to listed and non-listed mammals are not expected.

Chronic Risk

Risk quotients were calculated for dietary and dose-based chronic exposures. None of the 

trinexapac-ethyl uses yielded RQs that exceeded the LOC (1). Therefore, chronic direct 

effects to listed and non-listed mammals are not expected.

The SIP model identified drinking water as a potential exposure pathway for both acute and 

chronic risks for mammals. Before the registration review risk assessment is finalized, the 

input for the expected concentration in water will be re-visited. Currently, it is based on the 

conservative assumption that the concentration in drinking water is equal to the solubility 

limit of trinexapac-ethyl. This is likely an overestimation and the true concentration would 

be much lower.

Summary of Risks from Direct Effects

A summary of the potential for acute and chronic risks to mammals is listed below:
71

• The potential for acute risk to mammals is low for all trinexapac-ethyl uses, based on 

RQs not exceeding the listed species LOCs (0.1). 

• The potential for chronic risk to listed and non-listed mammals for all trinexapacethyl uses is low based on the RQs not exceeding the listed species LOC (1).

• There is a potential acute and chronic concern for mammals, based on the drinking 

water exposure pathway.

DIRECT EFFECTS TO TERRESTRIAL INVERTEBRATES

The Pollinator White Paper (USEPA 2012) has identified an LOC of 0.4 for honeybees. The 

level of direct effects to terrestrial invertebrates necessary to indirectly affect other taxa that 

rely on terrestrial invertebrates as a food source or for pollination has not been established on 

a national level, and the use of the interim LOC of 0.05 will apply to all terrestrial 

invertebrates without the demarcation of non-listed and listed, except for honeybees, for 

which an LOC of 0.4 will be used.

RQs were calculated for acute contact risks to terrestrial invertebrates and honeybees. 

Sugarcane, grasses grown for seed, and turf uses exceeded the terrestrial invertebrate LOC of 

0.05. There is a 1 in 260 (sugarcane), 1 in 64 (grasses grown for seed), 1 in 181 (turf at 0.34 

lb ai/A), 1 in 33 (turf at 0.68 lb ai/A), and 1 in 7 (turf at 1.36 lb ai/A) chance of individual

mortality by these uses.

None of the uses exceeded the honeybee LOC of 0.4. Acute oral toxicity data or larval 

toxicity data were not available for honeybees; these were recently identified by the 

Pollinator White Paper (USEPA 2012) as being useful endpoints for assessing risks to 

terrestrial invertebrates. When available, the acute oral toxicity value in honeybees is usually 

lower (more toxic) than the acute contact toxicity value. Thus, it is assumed that terrestrial 

invertebrates would also be at risk via dietary exposures. Given that the honeybee acute 

contact RQs did not indicate concerns for honeybees, it is uncertain if there would be risk 

concerns for the oral exposure pathway for honeybees. Similarly, for both terrestrial 

invertebrates and honeybees, the risk concerns to larvae are unknown.

Buffers around habitat may offer one mitigation strategy for acute contact risks to terrestrial 

invertebrates. See the acute avian section above for further description on the AgDrift 

program and the parameters used in the model. The results indicate that buffers of up to 3.28 

ft would be protective of applications of sugarcane (ground and aerial) and grasses grown for 

seed (ground) while buffers up to 19.68 ft would be protective of aerial application of grasses 

grown for seed and turf. These results are only relevant to acute contact toxicity because 

data are not available for acute oral toxicity in terrestrial invertebrates (Table 31). Buffers 

could provide protection for off-site exposures, but terrestrial invertebrates on the treated 

areas may still be at risk.

Table 31. Terrestrial invertebrate buffers for trinexapac-ethyl calculated with 

AgDRIFT

Use Single Application Rate (lb ai/A) Fraction of Applied Buffer Distance (ft)

Sugarcane (ground) 0.31 0.625 3.28

Sugarcane (aerial) 0.31 0.625 0
72

Use Single Application Rate (lb ai/A) Fraction of Applied Buffer Distance (ft)

Grasses grown for seed 

(ground) 0.5 0.385 3.28

Grasses grown for seed 

(aerial) 0.5 0.385 19.68

Turf (ground) 0.34 0.56 6.56

Turf (ground) 0.68 0.29 9.84

Turf (ground) 1.36 0.14 19.68

Summary of Risks from Direct Effects

A summary of the potential for acute risks to terrestrial invertebrates is listed below:

• There is the potential for acute contact and dietary risk to terrestrial invertebrates for 

the sugarcane, grasses grown for seed, and turf uses, based on RQs.

• The potential for direct acute contact risks to honeybees is unlikely, based on RQs.

• The potential for direct acute dietary risks to honeybees is unknown because oral 

toxicity data are not available.

• Risk concerns for larvae of terrestrial invertebrates and honeybees are unknown 

because data are not available.

 DIRECT EFFECTS TO TERRESTRIAL PLANTS

Risk quotients were calculated for listed and non-listed terrestrial plants. None of the RQs 

exceeded the LOC for the cereals uses (barley, wheat, oats, and triticale). Direct risk 

concerns were identified for the other uses (Tables 32-33). Listed and non-listed semiaquatic monocots and dicots had RQs above the LOC for all of the remaining uses. At rates 

of 0.5 lb ai/A and higher, non-listed semi-aquatic monocots and dicots were also affected. In 

addition, at the highest turf application rate (1.36 lb ai/A), listed dry monocots and dicots 

exceeded the LOC; the spray drift RQ for listed monocots also exceeded the LOC for this 

scenario. Therefore, the RQ analysis indicates direct risk concerns for terrestrial plants for 

the sugarcane, grasses grown for seed, and turf uses.
73

Table 32. Trinexapac-ethyl application scenarios that exceeded the LOC for listed and non-listed monocots

Use Non-listed monocot Listed monocot

Dry Semi-aquatic Spray drift Dry Semi-aquatic Spray drift

Ground Aerial/ 

Chem

Ground Aerial/ 

Chem

Ground Aerial/

Chem

Ground Aerial/ 

Chem

Ground Aerial/ 

Chem

Ground Aerial/ 

Chem

Sugarcane No No No No No No No No Yes Yes No No

Grasses grown for seed No No No No No No No No Yes Yes No No

Turf (0.34 lb ai/A0 No No No No No No No No Yes Yes No No

Turf (0.68 lb ai/A) No No Yes Yes No No No No Yes Yes No No

Turf (1.36 lb ai/A) No No Yes Yes No No No Yes Yes Yes No Yes

Table 33. Trinexapac-ethyl application scenarios that exceeded the LOC for listed and non-listed dicots

Use Non-listed dicot Listed dicot

Dry Semi-aquatic Spray drift Dry Semi-aquatic Spray drift

Ground Aerial/ 

Chem

Ground Aerial/ 

Chem

Ground Aerial/

Chem

Ground Aerial/ 

Chem

Ground Aerial/ 

Chem

Ground Aerial/ 

Chem

Sugarcane No No No No No No No No Yes Yes No No

Grasses grown for seed No No Yes Yes No No No No Yes Yes No No

Turf (0.34 lb ai/A0 No No No No No No No No Yes Yes No No

Turf (0.68 lb ai/A) No No Yes Yes No No No No Yes Yes No No

Turf (1.36 lb ai/A) No No Yes Yes No No No Yes Yes Yes No No
74

Buffers around habitat may offer a potential mitigation strategy to reduce the concentration 

of trinexapac-ethyl that reaches non-target terrestrial plants. The TerrPlant analysis indicated 

that most of the risk was a result of runoff, not spray drift. When the spray drift input was set 

to “0,” the semi-aquatic and dry plant RQs dropped slightly, but not enough to lower the RQ

below the LOC of 1. Consequently, mitigation options should focus on runoff. In general, 

pesticide exposure will be less for plants farther from the use site, thus buffers may be a 

useful mitigation option for plants affected by runoff.

One uncertainty is that for the turf uses, there are several products that are mixed with 

flurprimidol and paclobutrazol. These chemicals are also plant growth regulators and may 

subject non-target plants to additional stress. It is unknown if the effects of these chemicals 

would be additive, synergistic, or cause inference in the mechanism of action.

Summary of Risks from Direct Effects

A summary of the potential for risks to terrestrial plants is listed below:

• There is a potential for direct effects to listed monocots and dicots from the 

sugarcane, grasses grown for seed, and turf uses, based on the RQ analysis.

• There is a potential for direct effects to non-listed semi-aquatic monocots and dicots 

from grasses grown for seed and two highest turf application uses, based on the RQ 

analysis.

• Runoff is the main driver of the risk concerns.

DIRECT EFFECTS TO AQUATIC FISH, INVERTEBRATES, AND PLANTS

Freshwater Fish and Amphibians (Aquatic-Phase), and Estuarine-Marine Fish

Acute Risk

Acute RQs for freshwater fish (surrogate for aquatic-phase amphibians) and estuarine/marine 

fish were all less than 0.01 and did not exceed the acute listed species LOC of 0.05. 

Therefore, direct adverse effects to freshwater fish, aquatic-phase amphibians, and 

estuarine/marine fish on an acute exposure basis are not expected from the registered uses of 

trinexapac-ethyl.

Chronic Risk

Chronic RQs for freshwater fish (surrogate for aquatic-phase amphibians) were all less than 

0.01 and did not exceed the chronic LOC of 1. Consequently, direct chronic risk concerns to 

freshwater fish from the registered uses of trinexapac-ethyl are not expected.

Chronic estuarine/marine fish data were not available for risk analysis. Chronic data from 

freshwater fish were considered a protective and conservative surrogate because freshwater 

fish were five times more sensitive to trinexapac-ethyl on an acute basis than 

estuarine/marine fish. All of the risk quotients were below 0.01 and did not exceed the LOC 

of 1. Therefore, direct adverse chronic effects to estuarine/marine fish are not expected from 

the registered uses of trinexapac-ethyl.

Freshwater and Estuarine-Marine Invertebrates

Acute Risk
75

Acute RQs for freshwater invertebrates could not be calculated because the acute toxicity 

value was non-definitive. In lieu of this, the LC50 (> 145,500 μg ai/L) was compared directly 

to the highest peak EEC (6.78 μg ai/L). The LC50 is much higher than the peak EEC 

indicating that direct risk concerns from acute exposures are not expected for all of the 

registered trinexapac-ethyl uses. 

Acute RQs for estuarine/marine invertebrates were all below 0.01 and did not exceed the 

acute listed species LOC of 0.05. Thus, direct risk concerns from acute exposures to 

estuarine/marine invertebrates are not expected.

Chronic Risk

The chronic RQs for freshwater invertebrates were less than 0.01 and did not exceed the 

LOC of 1. Therefore, no direct risk concerns for freshwater invertebrates were identified for 

the registered trinexapac-ethyl uses.

Chronic toxicity data were not available for estuarine/marine invertebrates. The acute data 

for estuarine/marine invertebrates showed them to be more sensitive to trinexapac-ethyl than 

their freshwater counterparts. Consequently, the chronic data from freshwater invertebrates 

could not be used as a surrogate, as was done for estuarine/marine fish. Chronic toxicity 

values were calculated for the parent using EpiSuite; however, the predicted toxicity values 

were poor matches when compared with acute and chronic endpoints that were available. 

Using an acute-to-chronic ratio (ACR) was explored as well. One drawback to this method is 

that the freshwater invertebrate acute toxicity value is non-definitive. Taking the absolute 

value of this number and using it in the ACR approach may underestimate chronic toxicity. 

However, given that the calculated NOAEC by this method yielded RQs from <0.01 to 0.04, 

the actual toxicity value would need to be 21 times more sensitive to result in an RQ of 1. 

Considering all of these approaches, it was decided to rely on the ACR toxicity estimate. 

Therefore, no direct chronic risk concerns are expected for the registered uses of trinexapacethyl for estuarine/marine invertebrates.

Aquatic Plants – Vascular and Non-vascular

RQs for vascular aquatic plants ranged from <0.01 to 0.38. RQs for non-vascular plants 

ranged from <0.01 to 0.06. None of the RQs exceeded the LOC of 1; consequently, direct 

risk concerns are not expected for listed or non-listed vascular and non-vascular aquatic 

plants for the registered uses of trinexapac-ethyl

Summary of Risk from Direct Effects

A summary of the potential for risks to aquatic organisms is listed below:

• Direct acute and chronic risk concerns were not identified for freshwater fish, 

aquatic-phase amphibians, and estuarine/marine fish for the registered uses of 

trinexapac-ethyl.

• Direct acute and chronic risk concerns were not identified for freshwater and 

estuarine/marine invertebrates for the registered uses of trinexapac-ethyl.

• Direct risk concerns to aquatic vascular and non-vascular plants were not identified 

for the registered uses of trinexapac-ethyl
76

 

Listed Species Effects Analysis

The direct and indirect effects analysis for general taxa of listed species is summarized in 

Table 34, for trinexapac-ethyl uses. The analysis is based on the direct and indirect effects 

concluded from the analysis of risk estimates. 
77

Table 34. Summary of indirect and direct effects to listed species and preliminary effects determination for trinexapac-ethyl 

uses 

Listed species 

group

Direct Effect 

Assessment Endpoints

Direct Effects Indirect

Effects

Effects Determination

Non-vascular 

Aquatic Plant 

Species

Primary productivity No Effect – risk 

quotients below 

LOC. 

Direct effects to non-listed and listed terrestrial plants may occur from 

trinexapac-ethyl spray drift or runoff. This could result in reduced growth of 

non-target plants and modify the structural habitat near aquatic environments. 

It could affect non-vascular plant habitat by changing the water temperature, 

dissolved oxygen levels, sedimentation, etc. 

Currently, there are no listed non-vascular aquatic plant species, therefore 

adverse effects to listed non-vascular plants are not expected. 

No Effect

Vascular 

Aquatic Plant 

Species

Primary productivity 

assessed from effects on 

main stem length, total 

stem length (main + 

laterals), and fresh 

weight

No Effect – risk 

quotients below 

LOC. 

Direct effects to non-listed and listed terrestrial plants may occur from 

trinexapac-ethyl spray drift or runoff. This could result in reduced growth of 

non-target plants and modify the structural habitat near aquatic environments. 

It could affect vascular plant habitat by changing the water temperature, 

dissolved oxygen levels, sedimentation, etc. Direct effects were also 

identified for terrestrial invertebrates. They may provide pollination services 

to vascular aquatic and the reproductive cycle of vascular plants may be 

disrupted if terrestrial invertebrates are affected by trinexapac-ethyl uses. 

Birds (surrogate for reptiles and land-phase amphibians) were also directly 

affected by trinexapac-ethyl. They may provide seed dispersal services or 

modify local environments via nesting, foraging, or other activities. 

Effects uncertain based on indirect effects from direct effects on terrestrial 

plants, terrestrial invertebrates, birds, reptiles, and land-phase amphibians.

Uncertain*

Freshwater 

Fish and 

Amphibians

Acute mortality No Effect – risk 

quotients below 

LOC.

Direct effects to terrestrial invertebrates are expected. They may be a 

primary food source for freshwater fish and amphibians. 

Direct effects to birds, reptiles, and land-phase amphibians are expected. 

These organisms may prey upon fish and amphibians and play an important 

role in population control. Furthermore, they may modify the environment 

(i.e., burrows or indentations that fill with water and act as habitat for 

Uncertain*
78

Listed species 

group

Direct Effect 

Assessment Endpoints

Direct Effects Indirect

Effects

Effects Determination

Chronic survival, growth 

and reproduction 

No Effect – risk 

quotients below 

LOC. 

aquatic-phase amphibians or ephemeral fish) in ways that are important for 

fish and aquatic-phase amphibians. 

Direct effects to non-listed and listed terrestrial plants may occur from 

trinexapac-ethyl spray drift or runoff. This could result in reduced growth of 

non-target plants and modify the structural habitat near aquatic environments. 

It could affect freshwater fish and amphibian habitat by changing the water 

temperature, dissolved oxygen levels, sedimentation, etc. It may also modify 

food sources as other aquatic organisms could be affected. 

Effects uncertain based on direct effects to terrestrial plants, terrestrial 

invertebrates, and birds, reptiles, and land-phase amphibians.

Freshwater 

Invertebrates

Acute mortality No Effect – risk 

quotients below 

LOC.

Direct effects to non-listed and listed terrestrial plants may occur from 

trinexapac-ethyl spray drift or runoff. It could result in reduced growth of 

non-target plants and modify the structural habitat near aquatic environments. 

This could affect freshwater invertebrate habitat by changing the water 

temperature, dissolved oxygen levels, sedimentation, etc. It may also modify 

food sources as other aquatic organisms could be affected. 

Direct effects to birds, reptiles, and land-phase amphibians are expected. 

These organisms may prey upon freshwater invertebrates and play an 

important role in population control. Furthermore, they may modify the 

environment (i.e., burrows or indentations that fill with water and act as 

habitat) in ways that are important for aquatic invertebrates. 

Effects uncertain based on direct effects to birds, reptiles, and land-phase 

amphibians, and terrestrial plants.

Uncertain*

Chronic survival and 

reproduction 

No Effect – risk 

quotients below 

LOC. 

Estuarine/ 

Marine Fish

Acute mortality No Effect – risk 

quotients below 

LOC. 

Direct effects to non-listed and listed terrestrial monocots may occur from 

trinexapac-ethyl spray drift or runoff. This could result in reduced growth of 

non-target plants and modify the structural habitat near aquatic environments. 

It could affect estuarine/marine fish habitat by changing the water 

Uncertain*
79

Listed species 

group

Direct Effect 

Assessment Endpoints

Direct Effects Indirect

Effects

Effects Determination

Assessment of chronic 

growth and survival

No Effect – risk 

quotients below LOC

(based on surrogate 

data). 

temperature, dissolved oxygen levels, sedimentation, etc. 

Direct effects to terrestrial invertebrates are expected. They may be a 

primary food source for estuarine/marine fish. 

Direct effects to birds are expected. They may prey upon fish and play an 

important role in population control. 

Effects uncertain based on direct effects to terrestrial plants, terrestrial 

invertebrates, and birds.

Estuarine/ 

Marine 

Invertebrates

Acute mortality No Effect – risk 

quotients below 

LOC. 

Direct effects to non-listed and listed terrestrial plants may occur from 

trinexapac-ethyl spray drift or runoff. This could result in reduced growth of 

non-target plants and modify the structural habitat near aquatic environments. 

It could affect estuarine/marine invertebrate habitat by changing the water 

temperature, dissolved oxygen levels, sedimentation, etc. 

Direct effects to birds are expected. These organisms may prey upon 

estuarine/marine invertebrates and play an important role in population 

control. Furthermore, they may modify the environment (i.e., burrows or 

indentations that fill with water and act as habitat) in ways that are important 

for aquatic invertebrates. 

Effects uncertain based on direct effects on terrestrial plants and birds.

Uncertain*

Assessment of chronic 

growth and reproductive 

effects

No Effect – risk 

quotients below LOC

(based on acute-tochronic ratio).

Non-target 

plants in 

terrestrial and 

semi-aquatic 

areas

Primary productivity 

assessed from effects on 

biomass as measured 

using survival and dry 

weight; incident data.

Risk quotients above 

LOC

Direct effects to birds, reptiles, and land-phase amphibians may adversely 

affect plants because some of these species act as seed dispersers and 

pollinators. Direct effects to terrestrial invertebrates may also affect 

pollination services. A reduction in these services could affect plant 

reproduction and establishment. 

Effects uncertain based on direct effects to birds, reptiles, and land-phase 

amphibians, and terrestrial invertebrates.

Uncertain*

Birds, 

Reptiles, and 

Land-Phase 

Acute mortality Risk quotients above

LOC.

Direct effects to non-listed and listed terrestrial plants may occur from 

trinexapac-ethyl spray drift or runoff. This could result in reduced growth of 

non-target plants and modify the structural habitat. Resources for nests, food, 

Uncertain*
80

Listed species 

group

Direct Effect 

Assessment Endpoints

Direct Effects Indirect

Effects

Effects Determination

Amphibians Chronic reproduction Risk quotients above

LOC. 

or camouflage may be diminished. 

Direct effects to terrestrial invertebrates may reduce prey availability for 

birds, reptiles, and land-phase amphibians. 

Effects uncertain based on direct effects to terrestrial plants and terrestrial 

invertebrates. 

Mammals Acute mortality No Effect – risk 

quotients below LOC

(based on dietary 

exposure). 

Direct effects to non-listed and listed terrestrial plants may occur from 

trinexapac-ethyl spray drift or runoff. This could result in reduced growth of 

non-target plants and modify the structural habitat. Resources for nests, food, 

or camouflage may be diminished. 

Direct effects to terrestrial invertebrates may reduce prey availability for 

mammal. It may also reduce the amount of fruit/seeds that are available if 

pollinator services are affected for key plants. 

Direct effects to birds, reptiles, and land-phase amphibians may reduce prey 

availability for carnivorous or omnivorous mammals.

Effects uncertain based on direct effects to terrestrial plants, terrestrial 

invertebrates, and birds, reptiles, and land-phase amphibians.

Uncertain*

Chronic Reproduction No Effect – Risk 

quotients below LOC

(based on dietary 

exposure).

Terrestrial 

Invertebrates

Acute mortality based on 

contact

Risk quotients above

LOC.

Direct effects to non-listed and listed terrestrial plants may occur from 

trinexapac-ethyl spray drift and runoff exposure; therefore, indirect effects 

could occur from an alteration in habitat in which a species relies on for 

forage, shelter, and/or reproduction needs.

Effects uncertain based on indirect effects from direct effects to terrestrial 

plants.

Uncertain*

* Although this preliminary assessment has, on a coarse biological geographical data set basis, identified potential concerns for effects on individuals of a listed species within 

the taxonomic group, it is possible that additional information and further analysis will lead to species-specific determinations of no effect, may affect not likely to adversely 

affect, or may affect likely to adversely affect. Sections of the document describing additional information sources, coupled with considerations of uncertainties, are likely to 

figure prominently in species-specific determinations.
81

ACTION AREA

In the case of a nation-wide risk assessment conducted under registration review, the action 

area will encompass the entire U.S. and its territories. The purpose of defining the action 

area as the entire U.S. and its territories is to ensure that the initial area of consideration 

encompasses all areas where the pesticide may be used now and in the future, including the 

potential for off-site transport via spray drift and downstream dilution. Additionally, the 

concept of a nation-wide action area takes into account the potential for direct and indirect 

effects and any potential modification to critical habitat based on ecological effect measures 

associated with reduction in survival, growth, and reproduction, as well as the full suite of 

sub-lethal effects available in the effects literature. 

It is important to note that the nationwide action area does not imply that direct and/or 

indirect effects and critical habitat modification are expected to or are likely to occur over the 

full extent of the action area, but rather to identify all listed species and critical habitat that 

may potentially be affected by the action. The Agency will use more rigorous analysis 

including consideration of available land cover data, toxicity data, and exposure information 

to determine areas where individual listed species and designated critical habitat may be 

affected or modified via endpoints associated with reduced survival, growth, or reproduction.

 

 EFFECTS AREA DETERMINATION

The potential for direct and/or indirect effects is possible to listed species from exposure to 

trinexapac-ethyl. 

Direct Effects

There are potential direct effects to listed species for the following taxa:

• Birds, Reptiles, and Land-Phase Amphibians (based on acute and chronic risk 

quotients exceeding the LOC)

• Terrestrial Plants (based on risk quotients exceeding the LOC)

• Terrestrial Invertebrates (based on acute contact risk quotients exceeding the LOC)

Indirect Effects

As there are potential direct effects to birds, reptiles, and land-phase amphibians, terrestrial 

plants, and terrestrial invertebrates, indirect effects could occur to other taxa.

• Indirect effects to listed fish, aquatic invertebrates, amphibians, reptiles, and other 

terrestrial organisms (e.g. birds, mammals and other invertebrates) that are dependent 

on terrestrial invertebrates, birds, reptiles, and land-phase amphibians, and plants for 

food.

• Indirect effects to terrestrial plants for which terrestrial animals (e.g. birds, reptiles, 

land-phase amphibians, and terrestrial invertebrates) are needed for reproduction (e.g. 

pollination, seed dispersal) as there may be a potential change in pollinator/seed 

disperser communities/populations. 

• Indirect effects to a listed species that is dependent on a bird, reptile, land-phase 

amphibian, or terrestrial invertebrate.
82

• Indirect effects to listed species that are dependent on a plant in terrestrial or semiaquatic areas during some phase of their life-cycle for things such as food, shelter, 

and reproductive habitats. 

The following table shows the potential taxa indirectly affected by direct effects (Table 35) 

Table 35. Organism groups that are potentially indirectly affected by direct effects to 

other organisms (specific to trinexapac-ethyl uses)

Taxon Directly Affected Taxon Indirectly Affected Reason for Indirect Effect

Birds, Reptiles, Land-Phase 

Amphibians

Reptiles, Birds, Plants, 

Amphibians, Mammals, Fish

Change in prey population (food 

source); Reduction in potential 

pollinators/seed dispersers; 

Reduction in habitats (e.g., 

burrows, nests)

Terrestrial Invertebrates Fish, Invertebrates, Reptiles, 

Amphibians, Plants, Mammals, 

Birds

Change in prey population (food 

source); Reduction in pollinator

services (plants only)

Terrestrial Plants All taxa (birds, mammals, reptiles, 

amphibians, fish, aquatic and 

terrestrial invertebrates)

Change in food sources; change in 

habitats

Based on this screening-level assessment, there are potential risks of direct effects to listed 

and non-listed birds, reptiles, and land-phase amphibians, terrestrial invertebrates, and 

terrestrial plants from the use of trinexapac-ethyl on some of its registered use sites. Listed 

species of all taxa may also be affected through indirect effects because of the potential direct 

effects on listed and non-listed species. Potential direct effects on listed and non-listed birds, 

reptiles, and land-phase amphibians, terrestrial invertebrates, and terrestrial plants from the 

use of trinexapac-ethyl may be associated with modification of primary constituent elements 

of designated critical habitats, where such designations have been made. However, at this 

current stage of the Registration Review process, it is premature to make effects 

determinations for listed species until further refinements are conducted. To make effects 

determinations for individual species, useful refinements may include analyses of 1) more 

detailed, species-specific ecological and biological data; 2) more detailed and accurate 

information on trinexapac-ethyl use patterns; and 3) sub-county level spatial proximity data 

for the co-occurrence of potential effects areas and listed species and any designated critical 

habitat. Examples of such refinements are described below.

EFED is currently developing tools that are expected to further refine the assessment and are 

designed to support effects determinations for individual federally listed species and their 

designated critical habitats (where applicable). Scientific information obtained from the U.S. 

Fish & Wildlife Service (USFWS), the National Marine Fisheries Service (NMFS), and other 

reliable sources is being collated by EFED to address all currently listed species. The 

information will be stored in an Office of Pesticide Programs Pesticide Registration 

Information SysteM (PRISM) knowledgebase. The listed species knowledgebase will 

consist of an information repository that houses biological and behavioral information 

relevant to individual species (e.g., habitat, diet, and life history, including specific temporal 

and spatial associations) and a document repository that contains supporting documents (e.g., 

USFWS recovery plans) and electronic information (e.g., GIS data files). For terrestrial taxa, 
83

the biological information relevant to risk quotient (RQ) calculations (e.g., diet and body 

weight) will be used to parameterize exposure estimates to derive species-specific RQs using 

a method consistent with currently used methods in the T-REX and T-HERPS models. 

Refinements may also include more detailed analyses of the registered uses and their use 

patterns that result in LOC exceeding the EEC for federally listed species in the screeninglevel assessment. The analyses may include more information on where, when, and how 

trinexapac-ethyl is used on all use sites. Actual usage data (when available) and national 

land-cover datasets that indicate potential use sites [e.g., national land cover dataset (NLCD), 

crop data layer (CDL)] may be used to support a more refined analysis of where trinexapacethyl is reasonably expected to be used. The majority of trinexapac-ethyl uses are for turf; 

layers that depict golf course, park, residential, or other turf locations would refine the 

assessment. Similarly, refinements for the timing of applications and how trinexapac-ethyl is 

used may be based on the analysis of additional usage data, beyond what were available at 

the time of the screening-level assessment, and a more in-depth exploration of agronomic 

practices. 

The U.S. Environmental Protection Agency, along with the U.S. Department of Agriculture 

(USDA), the U.S. Fish and Wildlife Service (FWS), and the National Marine Fisheries 

Service (NMFS), have announced the availability of a report developed by the National 

Academy of Sciences’ National Research Council outlining recommendations on specific 

scientific and technical issues related to the development of endangered and threatened 

species risk assessments for pesticides that are compliant with the Endangered Species Act 

(ESA) and the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA). The EPA, 

USDA, FWS and NMFS asked the NRC to consider a range of scientific and technical issues 

including:

• identifying best available scientific data and information; 

• considering sub-lethal, indirect and cumulative effects; 

• assessing the effects of chemical mixtures and inert ingredients; 

• analyzing the effects of pesticide use through the use of models; 

• incorporating uncertainties into the evaluations; and 

• using geospatial information and datasets that can be employed by the agencies in the 

course of these assessments. 

After reviewing the NRC’s recommendations on these scientific and technical issues, the 

EPA and its federal partners will determine how these recommendations can be implemented 

and incorporated into the scientific approaches for developing listed species risk assessments. 

It is anticipated that any draft guidance and/or science policies developed by EPA and its 

federal partners as a result of the NAS recommendations would be released for public 

comment prior to implementation. 
84

The refinements based on individual species data; additional, detailed usage information, 

when available; and further recommendations from the NRC report are expected to help to 

more accurately identify potential areas of effect and to better inform effects and habitat 

determinations for listed species and any designated critical habitats. For example, if 

trinexapac-ethyl is used when a particular species of concern is not present (e.g., it is 

migratory) or is not co-located in space, then risk of potential direct effects to the species 

may often be precluded. If LOCs are still exceeded for monocots, mammals, freshwater 

invertebrates, estuarine/marine invertebrates, and freshwater fish after conducting the refined 

analyses, further analyses of the potential spatial and temporal co-occurrence of listed species 

of concern (and any designated critical habitat) may be conducted. The extent of possible 

refinement in the analyses of spatial/temporal co-occurrence will largely depend on the scale 

and quality of the available sub-county level use site (e.g., NLCD, CDL) and species location 

data.

The Agency has made several refinements to the list of endangered and threatened species 

that may be affected by trinexapac-ethyl sugarcane, grasses grown for seed, and turf uses. To 

date, there are 1421 listed species identified in the LOCATES database (v. 2.2.7, derived 

from USFWS and NMFS). The following refinement does not apply to the turf uses, as 

LOCATES does not contain information on turf-use locations. For sugarcane and grasses 

grown for seed, a “no effect” call for 342 of the species for direct and indirect effects can be 

made based on a lack of geographical overlap, based on a county level of resolution, between 

the species and trinexapac-ethyl uses (Appendix J, Table J-1). A further 46 species can be 

eliminated from consideration of direct effects (i.e., “no effects”) based on species specific 

ecological and biological information from listed species trustee agencies (Appendix J, Table 

J-2). There are 794 species that will need to be considered in more depth before direct 

effects calls are made (Appendix J, Table J-3) for the sugarcane and grasses grown for seed 

uses. The biological, geographical, and use pattern information outlined above will be 

necessary to refine the assessment.
85

Uncertainties

A description of assumptions, uncertainties, strengths, and limitations of the basic risk 

assessment performed is described in Chapter 6 of the Agency’s Overview Document (EPA, 

2004) and includes those related to exposure for all taxa, those related to exposure for aquatic 

species, those related to exposure for terrestrial animals, those related to the effects 

assessment, and those associated with the acute LOC values. This Chapter discusses 

additional uncertainties associated with refinements made to the basic risk assessment.

Effects and Risk Assessment Uncertainties

Ecotoxicity Data Gaps

There were several ecotoxicity endpoints for which data were not available. 

• Estuarine/Marine Invertebrate (Chronic) OPPTS 850.1350. Data were not available 

for chronic effects to estuarine/marine invertebrates. In the absence of data, an acuteto-chronic ratio will be used in the registration review risk assessment.

• Estuarine/Marine Fish (Chronic) OPPTS 850.1400. Chronic data are not available for 

the sheepshead minnow. A comparison of acute endpoints shows that freshwater fish 

are more sensitive to trinexapac-ethyl than estuarine/marine fish. Therefore, the 

freshwater fish chronic toxicity value will be used as a surrogate for the 

estuarine/marine chronic toxicity value. 

• Honeybee Oral Toxicity (Acute) OECD 213. Acute oral toxicity data are not 

available for the honeybee. As outlined in the Pollinator White Paper, this study is 

necessary to conduct a complete risk assessment on honeybees, which currently act as 

surrogates for terrestrial invertebrates. In the absence of these data, the results from 

the acute contact toxicity analysis were extrapolated to acute oral toxicity.

• Honeybee Larvae Toxicity Non-Guideline. Larval toxicity information is not 

available for the honeybee. As outlined in the Pollinator White Paper, this study is 

necessary to conduct a complete risk assessment on honeybees, which currently act as 

surrogates for terrestrial invertebrates. In the absence of these data, risk was assumed 

for terrestrial invertebrate larvae, based on the results of the acute contact toxicity 

analysis. 

Mixture Toxicity

There are several trinexapac-ethyl products that contain paclobutrazol and/or flurprimidol as 

active ingredients. Both of these are also plant growth regulators and it is uncertain if there 

could be additional adverse effects on terrestrial plants from their use. Tank mixing is 

another source of uncertainty.

Fate Data Gaps

Currently, there are no outstanding data requirements for trinexapac ethyl. However, aside 

from a hydrolysis and an adsorption/desorption study for trinexapac acid (CGA-179500) 

there are no other data are available for the degradates of concern. A total toxic residue 

(TTR) approach was employed for this assessment, including parent and major 

environmental degradates including CGA-179500, CGA-313458, the open chain 
86

cyclohexane ring, and the unidentified hydroproduct M3. This approach is expected to 

provide protective exposure estimation for aquatic organisms exposed to the major 

degradates of trinexapac-ethyl. It assumes that the degradates have equivalent fate and 

ecotoxicity properties as the parent – a conservative assumption.

Incomplete Life Histories of Listed Species

Currently, a database of life histories for each of the listed animals and plants is not available 

for use by EFED. These life histories would include information such as body size at each 

life stage, food sources, relationships with other taxa, habitat, and reproductive habits. As 

such, conservative (protective) assumptions were made concerning the potential relationships 

between species in that each species was assumed to have a relationship with the other taxa. 

This is assumed to be an overestimation of the actual species that have a species dependant 

relationship. 

Locations of Listed Species

In addition, the specific occurrences of listed species are not known in some cases beyond the 

county-level. If the location of a species was not known in greater detail than the county 

level, the species was assumed to occur anywhere within that county at any time. Likewise, 

crop location data are also uncertain. Crops may rotate every year and some spatial datasets 

combine several crop types, making it impossible to distinguish one crop from another. 

Further, timing may play a role in the location of species and whether it overlaps with the 

time that a particular crop is in a field. These assumptions may lead to an overestimation of 

co-occurrence with trinexapac-ethyl exposure and overestimation of the number of species 

potentially at risk.

Other Routes of Exposure

Screening-level risk assessments for applications of pesticides consider dietary exposure 

alone. Other routes of exposure, not considered in this assessment, are discussed below:

Incidental soil ingestion exposure - This risk assessment does not consider incidental soil 

ingestion. Available data suggest that up to 15% of the diet can consist of incidentally 

ingested soil depending on the species and feeding strategy (Beyer et al., 1994). This route 

of exposure may be important for applications of trinexapac-ethyl for spray applications.

Dermal Exposure - The screening assessment does not consider dermal exposure, except as it 

is indirectly included in calculations of risk quotient’s based on lethal doses per unit of 

pesticide treated area. Dermal exposure may occur through three potential sources: (1) direct 

application of spray to terrestrial wildlife in the treated area or within the drift footprint, (2) 

incidental contact with contaminated vegetation, or (3) contact with contaminated water or 

soil. As foliar applications are primary application routes on the registered labels for 

trinexapac-ethyl, dermal contact with trinexapac-ethyl to non-target animals may occur.

Foliar Dissipation Half-life

An additional source of uncertainty is the foliar dissipation half-life, which is useful for spray 

applications to foliage. No half-life data were provided, thus a default of 35 days was used. 

It is not known if this half-life over or under-estimates the true half-life for trinexapac-ethyl. 
87

Species Sensitivity

Although the screening-level risk assessment relies on a selected toxicity endpoint from the 

most sensitive species tested, it does not necessarily mean that the selected toxicity endpoints 

reflect the sensitivity of the most sensitive species existing in a given environment. The 

relative position of the most sensitive species tested in the distribution of all possible species 

is a function of the overall variability among species to a particular chemical. In the case of 

listed species, there is uncertainty regarding the relationship of the listed species’ sensitivity 

and the most sensitive species tested.

The Agency is not limited to a base set of surrogate toxicity information in establishing risk 

assessment conclusions. The Agency also considers toxicity data on non-standard test 

species when available.

Endocrine Disruptor Screening Program (EDSP) 

As required by FIFRA and FFDCA, EPA reviews numerous studies to assess potential 

adverse outcomes from exposure to chemicals. Collectively, these studies include acute, 

subchronic and chronic toxicity, including assessments of carcinogenicity, neurotoxicity, 

developmental, reproductive, and general or systemic toxicity. These studies include 

endpoints which may be susceptible to endocrine influence, including effects on endocrine 

target organ histopathology, organ weights, estrus cycling, sexual maturation, fertility, 

pregnancy rates, reproductive loss, and sex ratios in offspring. For ecological hazard 

assessments, EPA evaluates acute tests and chronic studies that assess growth, developmental 

and reproductive effects in different taxonomic groups. As part of its recent registration on 

cereals (USEPA 2011a), EPA reviewed these data and selected the most sensitive endpoints 

for relevant risk assessment scenarios from the existing hazard database. However, as 

required by FFDCA section 408(p), trinexapac-ethyl is subject to the endocrine screening 

part of the Endocrine Disruptor Screening Program (EDSP). 

EPA has developed the EDSP to determine whether certain substances (including pesticide 

active and other ingredients) may have an effect in humans or wildlife similar to an effect 

produced by a “naturally occurring estrogen, or other such endocrine effects as the 

Administrator may designate.” The EDSP employs a two-tiered approach to making the 

statutorily required determinations. Tier 1 consists of a battery of 11 screening assays to 

identify the potential of a chemical substance to interact with the estrogen, androgen, or 

thyroid (E, A, or T) hormonal systems. Chemicals that go through Tier 1 screening and are 

found to have the potential to interact with E, A, or T hormonal systems will proceed to the 

next stage of the EDSP where EPA will determine which, if any, of the Tier 2 tests are 

necessary based on the available data. Tier 2 testing is designed to identify any adverse 

endocrine-related effects caused by the substance, and establish a dose-response relationship 

between the dose and the E, A, or T effect. 

Under FFDCA section 408(p), the Agency must screen all pesticide chemicals. Between 

October 2009 and February 2010, EPA issued test orders/data call-ins for the first group of 

67 chemicals, which contains 58 pesticide active ingredients and 9 inert ingredients. 

Trinexapac-ethyl is not among the group of 58 pesticide active ingredients on the initial list 
88

to be screened under the EDSP. Accordingly, as part of registration review, EPA will issue 

future EDSP orders/data call-ins, requiring the submission of EDSP screening assays for

trinexapac-ethyl. For further information on the status of the EDSP, the policies and 

procedures, the list of 67 chemicals, future lists, the test guidelines and the Tier 1 screening 

battery, please visit our website: http://www.epa.gov/endo/.

Spatial Analysis

Data are not available for turf uses, which represent the bulk of the labels and a large 

geographical area. Data are not available for the percent of cropped areas and changes in 

crops (e.g., crop rotation or permanent shifts) over time. This remains an uncertainty, 

particularly for the proximity analysis for listed species. Additionally, future expansions in 

the use of trinexapac-ethyl are not considered. As labels change and uses are expanded, the 

result may be a larger geographical area in which trinexapac-ethyl can be used. 
89

References

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trinexapac-ethyl influence creeping bentgrass growth, quality, and putting green 

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Coulston and F. Korte, eds., Environmental Quality and Safety: Chemistry, Toxicology, 

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Prevention, Pesticides and Toxic Substances, Office of Pesticide Programs, Washington, 

D.C., January 23, 2004.

United States Environmental Protection Agency (EPA). 2011a. EFED environmental risk 

assessment of proposed label for Palisade EC and Palisade 2 EC (trinexapac-ethyl), new 

uses on cereals, sugarcane and grasses grown for seed – revised. Environmental Fate and 

Effects Division, Office of Pesticide Programs, United States Environmental Protection 

Agency.

United States Environmental Protection Agency (EPA). 2011b. The Drinking Water 

Degradates Identification Memorandum for Trinexapac Ethyl. DP 389767. 

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Environmental Protection Agency, May 24, 2011
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USEPA. 2012. White paper in support of the proposed risk assessment process for bees. 

Environmental Protection Agency, Health Canada, and California Department of 

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Final Draft. March 1998.
91

Appendix A – Bibliography of MRIDs

Ecological Effects Studies

MRID 41563901. Hakin, B., and M. Rogers. 1989. Acute oral toxicity (LD50) of CGA-163935 to the mallard 

duck. Laboratory Report No. CBG 479/89145. Conducted by Huntingdon Research Centre, LKtd., CibaGeigy Corporation, Greensboro, NC.

MRID 41563902. Hakin, B., A.J. Norman, A. Anderson, and I.S. Dawe. 1989. The dietary toxicity (LC50) of 

CGA-163935 to the bobwhite quail. Laboratory Report No. CBG 478/89284, Conducted by Huntingdon 

Research Centre, Ltd., England. For Ciba-Geigy Corporation, Greensboro, NC.

MRID 41563903. Hakin, B., M. Rogers, A.J. Norman, A. Anderson, and I.S. Dawe. 1989. The dietary toxicity 

(LC50) of CGA-163935 to the mallard duck. Laboratory Report No. CBG 477/891195, Conducted by 

Huntingdon Research Centre, Ltd., England. For Ciba-Geigy Corporation, Greensboro, NC.

MRID 41563904. Smith, G.J., M.F. Yancey, H.O. Pate, D.L. Martin. 1990. Static renewal actue 96-hour 

toxicity of CGA-163935 to bluegill sunfish. Conducted by Battelle Columbus Division, Columbus, OH. 

Laboratory Report No. SC900020. Agricultural Division, Ciba-Geigy Corporation, Greensboro, NC.

MRID 41563905. Smith, G.J., M.F., Yancy, H.O. Pate, and D.L. Martin. 1990. Static renewal acute 96-hour 

toxicity of CGA-163935 to rainbow trout. Conducted by Battelle Columbus Division, Columbus, OH. 

Laboratory Report No. SC900019. Agricultural Division, Ciba-Geigy Corporation, Greensboro, NC.

MRID 41563906. Smith, G.J., M.F. Yancy, M.V. Johnson, and DD.L. Martin. 1990. Static renewal acute 48-

hour toxicity of CGA-163935 to Daphnia magna. Conducted by Battelle Colombus Division, Colombus, 

OH, Laboratory Report No. SC900018. Agricultural Division, Ciba-Geigy Corporation, Greensboro, NC.

MRID 41563908. Kuhn, J. (1988) Acute Oral Toxicity Study in Rats: CGA-163935 Tech- nical: Lab Project 

Number: 5645-88. Unpublished study prepared by Stillmeadow, Inc. 23 p.

MRID 41563909. Kuhn, J. (1990) Acute Oral Toxicity in Rats: CGA-163935 2E-A FL 900351: Lab Project 

Number: 6937-90. Unpublished study prepared by Stillmeadow, Inc. 20 p.

MRID 41563928. Hoxter, K. 1990. CGA-163935: an acute contact toxicity study with the honeybee. 

Wildlife International Ltd. Project No. 108-307. Submitted by Ciba Geigy Corp., Greensboro, NC.

MRID 41869504. Hakin, B. 1991. The effects of dietary inclusion of CGA 163935 on reproduction in the 

mallard duck. Study performed by Huntingdon Research Centre Ltd., Huntingdon, Cambridgeshire, UK. 

HRC Report No. CBG 457/90108. Submitted by Ciba-Geigy Corporation.

MRID 41869505. Hakin, B. 1991. The effects of dietary inclusion of CGA 163935 on reproduction in the 

bobwhite quail. Study performed by Huntingdon Research Centre, Ltd., Huntingdon, Cambridgeshire, UK. 

HRC Report No. CBG 475/9085. Submitted by Ciba-Geigy Corporation, Greensboro, NC.

MRID 41869506. Sousa, J. 1990. 96-hour acute toxicity to European carp Cyprinus carpio under flow 

through conditions. SLI Study #1781.0690.6255.171. Performed by Springborn Laboratories, Inc. 

Sponsored by Ciba-Geigy Corporation.

MRID 41869507. Sousa, J.V. 1991. (CGA-163935 technical) – acute toxicity to channel catfish (Ictalurus 

punctatus) under flow-through conditions. SLI Report No. 90-11-3579. Performed by Springborn 

Laboratories, Inc., Wareham, MA. Submitted by Ciba-Geigy Corporation, Greensboro, NC.

MRID 41869508. Sousa, J.V. 1991. (CGA-163935 technical) – Acute toxicity to mysid shrimp (Mysidopsis 

bahia) under flow-through conditions. SLI Report No. 91-1-3603. Performed by Springborn 

Laboratories, Inc., Wareham, MA. Submitted by CIBA-GEIGY Corporation, Greensboro, NC.

MRID 41869509. Dionne, E. 1991. CGA-163935 technical – Acute toxicity to eastern oysters (Crassostrea 

virginica). SLI Report No. 91-03-3701. Prepared by Springborn Laboratories, Inc., Wareham, MA. 

Submitted by Ciba-Geigy Corporation, Greensboro, NC.

MRID 41869510. Sousa, J.V. 1991. (CGA-163935 technical) – acute toxicity to sheepshead minnow 

(Cyprinodon variegatus) under flow-through conditions. SLI Report No. 91-1-3622. Performed by 

Springborn Laboratories, Inc., Wareham, MA. Submitted by Ciba-Geigy Corporation, Greensboro, NC.

MRID 41869511. Sousa, J.V. 1991. (CGA-163935 technical) – actue toxicity to fathead minnow (Pimphales 

promelas) embryos and larvae. SLI Report No. 91-3-3693. Study conducted by Springborn Laboratories, 

Inc., Wareham, MA. Submitted by Ciba-Geigy Corporation, Greensboro, NC.

MRID 41869512. Putt, A.E. 1991. 21-day chronic toxicity test with Daphnia magna under flow-through 

conditions. Performed by Springborn Laboratories, Wareham, MA. Report No. 91-3-3708. Submitted by 

Ciba Geigy Corporation.
92

MRID 41869514. Kuhn, J. (1991) Acute Oral Toxicity Study in Rats: Lab Project Number: 7674-90. 

Unpublished study prepared by Stillmeadow, Inc. 21 p.

MRID 41869529. White, T.L. 1991. Tier 2 seedling emergence nontarget phytotoxicity study using CGA 

163935. Laboratory Report No. LR90-435. Conducted by Pan-Agricultural Laboratories, Inc., Madera, 

CA. Submitted by Ciba-Giegy Corporation, Greensboro, NC.

MRID 41869531. White, T.L. 1991. Tier 2 vegetative vigor nontarget phytotoxicity study using CGA 163935. 

Laboratory Project No. LR90-433. Conducted by Pan-Agricultural Laboratories, Inc., Madera, CA. 

Submitted by Ciba-Giegy Corporation, Greensboro, NC.

MRID 41869532. Hoberg, J.R. 1991. CGA-163935 technical – toxicity to the duckweed Lemna gibba G3. 

SLI Report No. 91-3-3688. Conducted by Springborn Laboratoris, Inc., Wareham, MA. Submitted by 

Ciba-Giegy Corporation, Greensboro, NC.

MRID 41869533. Hoberg, J.R. 1991. CGA-163935 Technical – toxicity to the marine diatom Skeletonema 

costatum. Report No. 91-2-3676. Conducted by Sprinborn Laboratories, Inc., Wareham, MA. Submitted 

by Ciba-Giegy Corporation, Greensboro, NC.

MRID 41869534. Hoberg, J.R. 1991. CGA-163935 technical – toxicity to the freshwater diatom Navicula 

pelliculosa. Report No. 91-3-3683. Conducted by Springborn Laboratories, Inc., Wareham, MA. 

Submitted by Ciba-Giegy Corporation, Greensboro, NC.

MRID 41869535. Hoberg, J.R. 1991. CGA-163935 technical toxicity to the freshwater blue green alga 

Anabaena flos-aquae. SLI Report No. 91-3-3704. Prepared by Springborn Laboratories, Inc., Wareham, 

MA. Submitted by Agricultural Division, Ciba-Geigy Corporation, Greensboro, North Carolina.

MRID 42081401. Sousa, J. 1991. Early life stage, 35-day toxicity to fathead minnow larvae under flowthrough conditions. SLI Study #1781.0491.6279. Performed by Springborn Laboratories, Inc., Wareham 

MA. Submitted by Ciba-Geigy Corporation.

MRID 42595302. Chetram, R.S. 1992. Tier 2 seedling emergence nontarget phytotoxicity study using CGA163935 technical. Laboratory Study No. LR90-435. Conducted by Pan-Agricultural Laboratories, Inc., 

Madera, CA. Submitted by Ciba-Giegy Corporation, Greensboro, NC.

MRID 42595303. Hoberg, J.R. 1992. CGA-163935 Technical – toxicity to the duckweed Lemna gibba G3. 

SLI Report No. 92-11-4513. Conducted by Springborn Laboratories, Inc., Wareham, MA. Submitted by 

Agricultural Division, Ciba-Geigy Corporation, Greensboro, NC.

MRID 43128602. Putt, A. E. 1993. 21-day chronic toxicity study using Daphnia magna under flowthrough 

conditions. Laboratory Report No. 1781.0393.6361.130. Performed by Springborn Laboratories, 

Wareham, MA. Submitted by Ciba-Geigy Corporation.

MRID 43128604. Singh, A.; Hazelette, J.; Yau, E. (1991) CGA-163935 Technical: A Two-Generation 

Reproductive Toxicity Study in Rats: Lab Project Number: 892017. Unpublished study prepared by CibaGeigy Corp. 1165 p.

MRID 48043713. Cartee, T.L., T.Z. Kendall, and H.O. Krueger. 2009. Trinexapac-ethyl – a 96-hour toxicity 

test with the freshwater alga (Pseudokirchneriella subcapitata). Unpublished study performed by Wildlife 

International, Ltd., Easton, MD. Laboratory Report No.: 528A-183. Study sponsored by Syngenta Crop 

Protection, Inc., Greensboro, NC.

MRID 48894501. Redmond, C. 2010. Trinexapac-ethyl – Acute oral toxicity test (LD50) with zebra finch 

(Taeniopygia guttata). Unpuglished study performed by Springborn Smithers Laboratories, Snow Camp, 

NC. Laboratory study number 1781.4113. Study sponsored by Syngenta Crop Protection, Inc., 

Greensboro, NC. 

Environmental Fate Studies

MRID 41563930. Spare, W. (1990) Hydrolysis of ?Carbon 14|-CGA-163935: Lab Project Number: 12152: 65-

89. Unpublished study prepared by Agrisearch Inc. 101 p. 

MRID 46809301. Mamouni, A. (2002) [Hydroxymethylene-(Carbon 14)]-CGA 179500 (Trinexapac Acid): 

Hydrolysis at Four Different pH Values (Including Final Report Amendment 1). Project Number: 770670, 

T001423/06. Unpublished study prepared b: RCC Umweltchemie Ag. 61 p.

MRID 41563931. Spare, W. (1990) Aqueous Photolysis of ?Carbon 14|-CGA-163935: Lab Project Number: 

12164: 178-89. Unpublished study prepared by Agrisearch Inc. 163 p. 

MRID 42081403. Merritt, A. (1991) Photodegradation of Carbon 14-CGA-163935 in pH 7 Buffered Solution 

Under Artificial Sunlight: Lab Project Number: ABR-91026. Unpublished study prepared by Ciba-Geigy 

Corp. 189 p. 
93

MRID 42095402. Burnett, D. (1991) The Response to the EPA Review of the Primo/ Vision (CGA-163935) 

EUP Environmental Fate Studies: Lab Project Number: ABR-91061. Unpublished study prepared by CibaGeigy Corp. 48 p. 

MRID 46809302. Millais, A. (2001) [Hydroxymethylene-(Carbon 14)] CGA 163935 Aqueous Photolysis: 

Final Report. Project Number: NVR/059/012189, T001446/06. Unpublished study prepared by Huntingdon 

Life Sciences, Ltd. 96 p. Relates to L0001034.

MRID 41563932. Spare, W. (1990) Soil Photolysis of CGA-163935 by Artificial Light: Lab Project Number: 

12165: 179-89. Unpublished study prepared by Agrisearch Inc. 94 p.

MRID 42081406. Merritt, A. (1991) Photodegradation of Carbon 14-CGA-163935 in Soil Under Artificial 

Sunlight: Lab Project Number: ABR-91027. Unpublished study prepared by Ciba-Geigy Corp. 231 p. 

MRID 42095402. Burnett, D. (1991) The Response to the EPA Review of the Primo/ Vision (CGA-163935) 

EUP Environmental Fate Studies: Lab Project Number: ABR-91061. Unpublished study prepared by CibaGeigy Corp. 48 p.

MRID 41563933. Spare, W. (1990) Aerobic and Anaerobic Soil Metabolism of CGA- 163935: Lab Project 

Number: 12155: 71-89. Unpublished study prepared by Agrisearch Inc. 183 p. 

MRID 46809303. Mamouni, A. (2001) Degradation of [Hydroxymethylene-(Carbon 14)] CGA 163935 

(Trinexapac-Ethyl) and CGA 179500 (Trinexapac Acid) in Soils Under Aerobic Conditions (Including 

Final Report Amendment 1). Project Number: 770668, T001422/06. Unpublished study prepared by RCC 

Umweltchemie Ag. 89 p.

MRID 41563933. Spare, W. (1990) Aerobic and Anaerobic Soil Metabolism of CGA- 163935: Lab Project 

Number: 12155: 71-89. Unpublished study prepared by Agrisearch Inc. 183 p.

MRID 46809304. Muller-Kallert, H. (1993) [(Carbon 14)]CGA 163935: Degradation and Metabolism in 

Aquatic Systems: Final Report. Project Number: 315426, T001447/06. Unpublished study prepared by 

RCC Umweltchemie Ag. 87 p. Relates to L0001034.

MRID 41563934. Spare, W. (1990) Leaching Characteristics of CGA-163935: Lab Pro- ject Number: 12156: 

72-89. Unpublished study prepared by Agri- search Inc. 47 p. 

MRID 41563935. Spare, W. (1990) Leaching Characteristics of Aged CGA-163935: Lab Project Number: 

12157: 73-89. Unpublished study prepared by Agriearch, Inc. 68 p. 

MRID 41563936. Spare, W. (1990) Adsorption/Desorption of ?Carbon 14|-CGA-163935: Lab Project Number: 

12158: 74-89. Unpublished study prepared by Agrisearch Inc. 52 p. 

MRID 41563937. Spare, W. (1990) Adsorption/Desorption of ?Carbon 14|-CGA-163935 Acid: Lab Project 

Number: 12179: 262-89. Unpublished study pre- pared by Agrisearch Inc. 72 p.

MRID 41563938. Spare, W. (1990) Laboratory Soil Volatility of CGA-163935: Lab Pro- ject Number: 12193: 

88-90. Unpublished study prepared by Agri- search Inc. 59 p. 

MRID 41869541. Spare, W. (1991) The Volatilization of CGA-163935 From Bermuda Turf (A Laboratory 

Study): Lab Project Number: 12181: 158-90. Unpub- lished study prepared by Agrisearch Inc. 92 p. 

MRID 42095402. Burnett, D. (1991) The Response to the EPA Review of the Primo/ Vision (CGA-163935) 

EUP Environmental Fate Studies: Lab Project Number: ABR-91061. Unpublished study prepared by CibaGeigy Corp. 48 p.

MRID 41869539. Braxton, S.; Bird, R.; Wiepke, T. (1991) CGA-163935 2E--Field Diss- ipation-Turf-North 

Carolina: Lab Project Number: ETI 71TF01: ETI FDS-71-TF-01: MVTL 01-9004. Unpublished study 

prepared by Environmental Technologies Institute, Inc. & Minnesota Valley Testing Labs. 424 p. 

MRID 41869540. Rice, F.; Guyton, B.; Hallberg, C. (1991) Terrestrial Field Dissip- ation for CGA-163935 2E 

on Turf and Bare Ground, Illinois Site: Lab Project Number: 38641: 69-90: 38641-45. Unpublished study 

prepared by Agri-Growth Research, Inc. ABC Laboratories, Inc. 475 p. 

MRID 47101601. Gresham, M. (1992) Freezer Stability of CGA-163935 and CGA-179500 in Grass and Thatch 

+ Sod: Trinexapac-ethyl: Final Report. Project Number: 39487, T000073/91. Unpublished study prepared 

by Analytical Bio-Chemistry Labs Inc. 44 p.

MRID 45898909. Krauss, J. (1992) Outdoor Confined Accumulation Study on Rotational Crops After 

Bareground Soil Application of ((Carbon 14)-Cyclohexyl)-CGA-163935: Final Report: Lab Project 

Number: 23/92: MR 23/92: 89JK03. Unpublished study prepared by Ciba-Geigy Limited. 44 p.

MRID 41604207. Fackler, P. (1990) Bioconcentration and Elimination of (carbon 14)- Residues by Bluegill 

(Lepomis macrochirus) Exposed to CGA- 163935: Lab Project Number: 90-2-3236; 144-89; 145-89. 

Unpub- lished study prepared by Springborn Laboratories, Inc. 59 p. 
94

MRID 41869542. Fackler, P. (1991) Bioconcentration and Elimination of ?Carbon 14|- Residues by Bluegill 

(Lepomis macrochirus) Exposed to CGA-163935 : Lab Project Number: 90-2-3236: 144 145-89. 

Unpublished study prepared by Springborn Laboratories, Inc. 63 p. 

MRID 41869543. Fackler, P. (1991) CGA-163935-Flow-Through Bioconcentration Study with Bluegill 

Sunfish (Lepomis macrochirus) for Metabolites Cha- racterization and Identification: Lab Project Number: 

91-2-3654: 184-90. Unpublished study prepared by Springborn Laboratories, Inc. & Ciba-Geigy Corp. 99 

p. 

MRID 42095402. Burnett, D. (1991) The Response to the EPA Review of the Primo/ Vision (CGA-163935) 

EUP Environmental Fate Studies: Lab Project Number: ABR-91061. Unpublished study prepared by CibaGeigy Corp. 48 p.
95

Appendix B. Total Toxic Residue (TTR) Calculations

1. Aqueous Photolysis: MRID 46809302

Aqueous Photolysis: MRID 46809302

Total Residues: Phototransformation of Trinexapac-Ethyl in pH 7 Buffer

Days % Applied ln % Applied

incubation Trinexapac-ethyl CGA 179500 (acid) CGA 313458 Total Residues Total Residues

1 89.8 1.7 n.d. 91.5 4.5

1 88.8 1.2 0.4 90.4 4.5

2 84.2 1.8 0.6 86.6 4.5

2 79.6 1.7 0.8 82.1 4.4

3 70.0 2.8 1.1 73.9 4.3

3 66.8 3.5 1.9 72.2 4.3

5 60.4 4.6 2.0 67.0 4.2

5 59.9 3.7 2.8 66.4 4.2

7 42.5 5.3 3.8 51.6 3.9

7 43.7 4.1 4.1 51.9 3.9

10 30.0 5.3 4.1 39.4 3.7

10 33.2 4.8 5.8 43.8 3.8

15 15.9 1.0 6.5 23.4 3.2

15 10.0 1.8 6.1 17.9 2.9

Calculated Half-Life = 6.7 days

Correction Factor = 3.4 days of summer sunlight at 40 degrees North (pg. 26 and Table 2, pg. 32)

Environmental 

Phototransformation Half-Life = 22.8 days

SUMMARY OUTPUT

Regression Statistics

Multiple R 0.984904931

R Square 0.970037724

Adjusted R Squ 0.967540868

Standard Error 0.090325471

Observations 14

ANOVA

df SS MS F Significance F

Regression 1 3.169680874 3.169680874 388.5036185 1.65353E-10

Residual 12 0.097904289 0.008158691

Total 13 3.267585163

Coefficients Standard Error t Stat P-value Lower 95% Upper 95%Lower 95.0%Upper 95.0%

Intercept 4.652133857 0.040210216 115.6953217 1.16531E-19 4.564523323 4.739744 4.564523 4.739744

X Variable 1 -0.103182948 0.005234924 -19.71049514 1.65353E-10 -0.114588868 -0.09178 -0.11459 -0.09178

Irradiated Samples (Identified Compounds)

% applied radioactivity

Data obtained from Table 7, p. 37 of the study report. 

y = -0.1032x + 4.6521

R2 = 0.97

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

5.0

0 2 4 6 8 10 12 14 16

ln (% Applied Radioactivity)

Time (days)

Total Residues
96

2. Aerobic Soil Metabolism: MRID 46809303

90th Percentile Calculation

Soil Type: Half Life (days)

Swiss Loam 3.0

Swiss Sandy Loam 3.6 Column1

German Loamy Sand 5.2

Mean 3.933333333

n = 3 Standard Error 0.66

Median 3.6

Mode #N/A

Standard Deviation 1.137248141

Sample Variance 1.293333333

Kurtosis #DIV/0!

Skewness 1.205659497

s = sample deviation 1.14 Range 2.2

sq.rt. n = 1.73 Minimum 3

0.66 Maximum 5.2

Sum 11.8

Count 3

Confidence Level(80.0%) 1.238078958

5.2 days Represents the 90th percentile confidence bound on the mean half-life.
97

Total Residues: Aerobic Soil Metabolism of Trinexapac-ethyl in two Swiss soils and one German soil.

Swiss loam (Gartenacker)

Days % Applied ln % Applied

Incubation Trinexapac-Ethyl CGA-179500 (acid) Unidentified M3 Total Residues Total Residues

0 93.9 n.d. n.d. 93.9 4.5

0 97.2 n.d. n.d. 97.2 4.6

0.08 16.8 15.0 1.0 32.8 3.5

0.25 2.4 23.9 0.6 26.9 3.3

0.5 1.4 29.0 1.5 31.9 3.5

1 0.2 23.0 1.1 24.3 3.2

3 n.d. 13.8 n.d. 13.8 2.6

7 n.d. 10.4 n.d. 10.4 2.3

7 n.d. 12.1 n.d. 12.1 2.5

15 0.5 0.2 0.7 1.4 0.3

21 n.d. n.d. n.d. 0.0 #NUM!

21 n.d. n.d. n.d. 0.0 #NUM!

28 n.a. n.a. n.a. 0.0 #NUM!

80 n.a. n.a. n.a. 0.0 #NUM! 0 0

Results from Table 7, p. 47 of the study report.

n.d. = not detected or below LOQ (Table 7, page 47).

n.a. = not analyzed

Note: Chart includes data throughout Day 15. Intervals thereafter were non detects or not analyzed.

Calculated Half Life = 3.0 days

SUMMARY OUTPUT

Regression Statistics

Multiple R 0.922752113

R Square 0.851471462

Adjusted R Square 0.832905394

Standard Error 0.497923845

Observations 10

ANOVA

df SS MS F Significance F

Regression 1 11.37040739 11.37040739 45.86170285 0.000141803

Residual 8 1.983425243 0.247928155

Total 9 13.35383263

Coefficients Standard Error t Stat P-value Lower 95% Upper 95%Lower 95.0%Upper 95.0%

Intercept 3.806150972 0.194311177 19.58791583 4.79781E-08 3.358068595 4.254233 3.358069 4.254233

X Variable 1 -0.227925491 0.033656412 -6.772126908 0.000141803 -0.305537316 -0.15031 -0.30554 -0.15031

% Applied Radioactivity

y = -0.2279x + 3.8062

R2 = 0.8515

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

5.0

0 2 4 6 8 10 12 14 16

ln (% Applied Radioactivity)

Time (days)

Total Residues
98

Total Residues: Aerobic Soil Metabolism of Trinexapac-ethyl in two Swiss soils and one German soil.

Swiss Sandy loam (Weide)

Days % Applied ln % Applied

Incubation Trinexapac-Ethyl CGA-179500 (acid) Unidentified M3 Total Residues Total Residues

0 93.1 n.d. n.d. 93.1 4.5

0 93.5 n.d. n.d. 93.5 4.5

0.08 34.3 9.5 n.d. 43.8 3.8

0.25 4.8 19.0 0.6 24.4 3.2

0.5 1.4 23.5 2.3 27.2 3.3

1 0.6 23.7 1.9 26.2 3.3

3 0.3 12.8 1.2 14.3 2.7

7 n.d. 15.4 n.d. 15.4 2.7

7 n.d. 15.5 n.d. 15.5 2.7

15 n.d. 2.1 0.2 2.3 0.8

21 n.d. n.d. n.d. 0.0 #NUM!

21 n.d. n.d. n.d. 0.0 #NUM!

28 n.d. n.d. n.d. 0.0 #NUM!

80 n.a. n.a. n.a. 0.0 #NUM! 0 0

Results from Table 8, p. 48 of the study report.

n.d. = not detected or below LOQ (Table 8, page 48).

n.a. = not analyzed

Note: Chart includes data throughout Day 15. Intervals thereafter were non detects or not analyzed.

Calculated Half Life = 3.6 days

SUMMARY OUTPUT

Regression Statistics

Multiple R 0.888401016

R Square 0.789256365

Adjusted R Square 0.762913411

Standard Error 0.51898366

Observations 10

ANOVA

df SS MS F Significance F

Regression 1 8.069766762 8.069766762 29.96081438 0.000591888

Residual 8 2.154752313 0.269344039

Total 9 10.22451908

Coefficients Standard Error t Stat P-value Lower 95% Upper 95%Lower 95.0%Upper 95.0%

Intercept 3.807907591 0.202529617 18.80173206 6.6167E-08 3.340873458 4.274942 3.340873 4.274942

X Variable 1 -0.192015098 0.035079918 -5.473647265 0.000591888 -0.272909534 -0.11112 -0.27291 -0.11112

% Applied Radioactivity

y = -0.192x + 3.8079

R2 = 0.7893

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

5.0

0 2 4 6 8 10 12 14 16

ln (% Applied Radioactivity)

Time (days)

Total Residues
99

Total Residues: Aerobic Soil Metabolism of Trinexapac-ethyl in two Swiss soils and one German soil.

German Loamy Sand (Borstel)

Days % Applied ln % Applied

Incubation Trinexapac-Ethyl CGA-179500 (acid) Unidentified M3 Total Residues Total Residues

0 99.3 n.d. n.d. 99.3 4.6

0 100.2 n.d. n.d. 100.2 4.6

0.08 58.1 18.2 n.d. 76.3 4.3

0.25 38.2 19.8 n.d. 58.0 4.1

0.5 14.1 42.1 0.2 56.4 4.0

1 10.0 43.5 n.d. 53.5 4.0

3 2.4 33.5 n.d. 35.9 3.6

7 1.2 27.8 0.5 29.5 3.4

7 1.7 30.5 0.7 32.9 3.5

15 0.3 5.6 n.d. 5.9 1.8

21 0.8 1.7 n.d. 2.5 0.9

21 1.0 1.8 n.d. 2.8 1.0

28 0.9 3.0 n.d. 3.9 1.4

80 n.a. n.a. n.a. 0.0 #NUM! 0 0

Results from Table 9, p. 49 of the study report.

n.d. = not detected or below LOQ (Table 9, page 49).

n.a. = not analyzed

Note: Chart includes data throughout Day 28. Interval thereafter were non detects or not analyzed.

Calculated Half Life = 5.2 days

SUMMARY OUTPUT

Regression Statistics

Multiple R 0.959199422

R Square 0.920063531

Adjusted R Square 0.912796579

Standard Error 0.407510449

Observations 13

ANOVA

df SS MS F Significance F

Regression 1 21.02534039 21.02534039 126.6092799 2.24757E-07

Residual 11 1.826712422 0.166064766

Total 12 22.85205281

Coefficients Standard Error t Stat P-value Lower 95% Upper 95%Lower 95.0%Upper 95.0%

Intercept 4.236276177 0.147743496 28.67318226 1.0902E-11 3.911094936 4.561457 3.911095 4.561457

X Variable 1 -0.134051531 0.01191349 -11.25207891 2.24757E-07 -0.160272947 -0.10783 -0.16027 -0.10783

% Applied Radioactivity

y = -0.1341x + 4.2363

R2 = 0.9201

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

5.0

0 5 10 15 20 25 30

ln (% Applied Radioactivity)

Time (days)

Total Residues
100

3. Aerobic Aquatic Metabolism: MRID 46809304

90th Percentile Calculation

Aquatic System: Half Life (days)

Swiss River Water-Sand Sediment 12.3

Pond Water-Sandy Clay Loam Sediment 14.8 Column1

Mean 13.55

n = 2 Standard Error 1.25

Median 13.55

Mode #N/A

Standard Deviation 1.767766953

Sample Variance 3.125

Kurtosis #DIV/0!

Skewness #DIV/0!

s = sample deviation 1.77 Range 2.5

sq.rt. n = 1.41 Minimum 12.3

1.25 Maximum 14.8

Sum 27.1

Count 2

Confidence Level(80.0%) 3.847104421

17.4 days Represents the 90th percentile confidence bound on the mean half-life.
101

Total Residues: Aerobic Aquatic Metabolism of Trinexapac-Ethyl

Swiss River Water-Sand Sediment

Days % Applied ln % Applied

Incubation Trinexapac-Ethyl CGA-179500 (acid) Total Residues Total Residues

0 100.4 n.a. 100.4 4.6

0.25 99.3 n.a. 99.3 4.6

1 84.7 13.6 98.3 4.6

2 67.6 23.7 91.3 4.5

3 62.1 32.0 94.1 4.5

7 30.9 56.6 87.5 4.5

14 3.0 70.9 73.9 4.3

20 <0.01 47.2 47.2 3.9

27 <0.01 28.2 28.2 3.3

55 <0.01 4.2 4.2 1.4

83 n.a. n.a. 0.0 #NUM!

111 n.a. n.a. 0.0 #NUM!

Data obtained from Tables 10-13, pages 58-61 of the study report.

n.a. = not analyzed

Note: Chart includes data throughout Day 55. Intervals thereafter were not analyzed.

Calculated Half Life = 12.3 days

SUMMARY OUTPUT

Regression Statistics

Multiple R 0.982655838

R Square 0.965612496

Adjusted R Square 0.961314059

Standard Error 0.196460743

Observations 10

ANOVA

df SS MS F Significance F

Regression 1 8.670492767 8.670492767 224.6426513 3.87725E-07

Residual 8 0.308774588 0.038596824

Total 9 8.979267356

Coefficients Standard Error t Stat P-value Lower 95% Upper 95%Lower 95.0%Upper 95.0%

Intercept 4.752438537 0.078808309 60.30377514 6.35369E-12 4.570706251 4.934171 4.570706 4.934171

X Variable 1 -0.05622741 0.003751474 -14.98808364 3.87725E-07 -0.06487832 -0.04758 -0.06488 -0.04758

% Applied Radioactivity

Total System Analysis

y = -0.0562x + 4.7524

R2 = 0.9656

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

5.0

0 10 20 30 40 50 60

ln (% Applied Radioactivity)

Time (days)

Total Residues
102

Total Residues: Aerobic Aquatic Metabolism of Trinexapac-Ethyl

Pond Water-Sandy Clay Loam Sediment

Days % Applied ln % Applied

Incubation Trinexapac-Ethyl CGA-179500 (acid) Total Residues Total Residues

0 99.0 n.a. 99.0 4.6

0.25 101.1 n.a. 101.1 4.6

1 88.1 4.8 92.9 4.5

2 75.6 10.6 86.2 4.5

3 78.6 17.0 95.6 4.6

7 41.6 36.5 78.1 4.4

14 10.7 51.6 62.3 4.1

20 2.9 44.4 47.3 3.9

27 n.a. 36.1 36.1 3.6

55 n.a. 6.8 6.8 1.9

83 n.a. n.a. 0.0 #NUM!

111 n.a. n.a. 0.0 #NUM!

Data obtained from Tables 10-13, pages 58-61 of the study report.

n.a. = not analyzed

Note: Chart includes data throughout Day 55. Intervals thereafter were not analyzed.

Calculated Half Life = 14.8 days

SUMMARY OUTPUT

Regression Statistics

Multiple R 0.98989692

R Square 0.979895913

Adjusted R Square 0.977382902

Standard Error 0.124601104

Observations 10

ANOVA

df SS MS F Significance F

Regression 1 6.053817994 6.053817994 389.9290412 4.50317E-08

Residual 8 0.12420348 0.015525435

Total 9 6.178021474

Coefficients Standard Error t Stat P-value Lower 95% Upper 95%Lower 95.0%Upper 95.0%

Intercept 4.668182834 0.049982516 93.39631519 1.92818E-13 4.552922945 4.783443 4.552923 4.783443

X Variable 1 -0.046983013 0.002379294 -19.74662101 4.50317E-08 -0.05246967 -0.0415 -0.05247 -0.0415

Total System Analysis

% Applied Radioactivity

y = -0.047x + 4.6682

R2 = 0.9799

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

5.0

0 10 20 30 40 50 60

ln (% Applied Radioactivity)

Time (days)

Total Residues
103

4. Anaerobic Aquatic Metabolism: MRID 48043712

90th Percentile Calculation

Anaerobic Aquatic System: Half Life (days)

ND System 290

FL System 56 Column1

Mean 173

n = 2 Standard Error 117

Median 173

Mode #N/A

Standard Deviation 165.4629868

Sample Variance 27378

Kurtosis #DIV/0!

s = sample deviation 165.46 Skewness #DIV/0!

sq.rt. n = 1.41 Range 234

117 Minimum 56

Maximum 290

Sum 346

Count 2

Confidence Level(80.0%) 360.0889738

533 days Represents the 90th percentile confidence bound on the mean half-life.
104

Total Residues: Anaerobic Aquatic Metabolism of Trinexapac-Ethyl

Pond Water-Sandy Clay Loam Sediment (ND) System

Days % Applied ln % Applied

Incubation Trinexapac-Ethyl CGA-179500 (acid) Total Residues Total Residues

0 101.0 n.d. 101.0 4.6

0 100.3 n.d. 100.3 4.6

0.125 96.6 1.2 97.8 4.6

0.125 104.9 0.0 104.9 4.7

0.25 100.5 1.1 101.6 4.6

0.25 104.0 2.2 106.2 4.7

0.50 98.5 2.7 101.2 4.6

0.50 89.6 2.1 91.7 4.5

1 88.5 6.6 95.1 4.6

1 75.9 9.4 85.3 4.4

2 75.2 19.8 95.0 4.6

2 71.6 20.2 91.8 4.5

3 59.2 23.4 82.6 4.4

3 61.2 36.7 97.9 4.6

4 50.9 31.8 82.7 4.4

4 30.7 45.9 76.6 4.3

7 26.7 60.5 87.2 4.5

7 2.4 61.4 63.8 4.2

18 3.2 88.0 91.2 4.5

18 n.d. 87.6 87.6 4.5

39 n.d. 77.8 77.8 4.4

39 n.d. 86.2 86.2 4.5

59 n.d. 79.7 79.7 4.4

59 n.d. 76.6 76.6 4.3

91 n.d. 86.2 86.2 4.5

91 n.d. 75.0 75.0 4.3

121 n.d. 58.4 58.4 4.1

121 n.d. 70.2 70.2 4.3

182 n.d. 58.6 58.6 4.1

182 n.d. 64.6 64.6 4.2

273 n.a. n.a. 0.0 #NUM!

273 n.a. n.a. 0.0 #NUM!

360 n.a. n.a. 0.0 #NUM!

360 n.a. n.a. 0.0 #NUM!

Data obtained from Tables 7-8, pages 49-52 of the study report.

n.d. = not detected

n.a. = not analyzed

Note: Chart includes data throughout Day 182. Intervals thereafter were not included.

Calculated Half Life = 290 days

SUMMARY OUTPUT

Regression Statistics

Multiple R 0.772863799

R Square 0.597318451

Adjusted R Square 0.582936967

Standard Error 0.108620691

Observations 30

ANOVA

df SS MS F Significance F

Regression 1 0.490035286 0.490035286 41.53385396 5.57892E-07

Residual 28 0.330356726 0.011798455

Total 29 0.820392013

Coefficients Standard Error t Stat P-value Lower 95% Upper 95%Lower 95.0%Upper 95.0%

Intercept 4.523354863 0.023742033 190.5209599 3.90632E-45 4.474721514 4.571988 4.474722 4.571988

X Variable 1 -0.002390556 0.000370935 -6.444676405 5.57892E-07 -0.00315038 -0.00163 -0.00315 -0.00163

Total System Analysis

% Applied Radioactivity

y = -0.0024x + 4.5234

R2 = 0.5973

4.0

4.1

4.2

4.3

4.4

4.5

4.6

4.7

0 50 100 150 200

ln (% Applied Radioactivity)

Time (days)

Total Residues
105

Total Residues: Anaerobic Aquatic Metabolism of Trinexapac-Ethyl

Lake Water-Loamy Sand Sediment (FL) System

Days % Applied ln % Applied

Incubation Trinexapac-Ethyl CGA-179500 (acid) Total Residues Total Residues

0 107.4 0.0 107.4 4.7

0 101.0 1.0 102.0 4.6

0.125 85.6 2.3 87.9 4.5

0.125 84.2 2.0 86.2 4.5

0.25 76.5 4.8 81.3 4.4

0.25 75.1 4.8 79.9 4.4

0.50 81.3 4.1 85.4 4.4

0.50 72.1 7.6 79.7 4.4

1 62.7 16.2 78.9 4.4

1 62.4 20.2 82.6 4.4

2 53.1 25.7 78.8 4.4

2 38.0 43.2 81.2 4.4

3 33.5 34.2 67.7 4.2

3 28.6 42.7 71.3 4.3

4 25.1 35.9 61.0 4.1

4 29.0 37.9 66.9 4.2

7 9.0 48.5 57.5 4.1

7 11.3 45.2 56.5 4.0

18 0.7 56.3 57.0 4.0

18 1.6 49.0 50.6 3.9

39 n.d. 43.0 43.0 3.8

39 n.d. 46.9 46.9 3.8

59 n.d. 45.2 45.2 3.8

59 n.d. 41.5 41.5 3.7

91 n.d. 26.6 26.6 3.3

91 n.d. 27.5 27.5 3.3

121 n.d. 15.8 15.8 2.8

121 n.d. 17.5 17.5 2.9

182 n.a. n.a. 0.0 #NUM!

182 n.a. n.a. 0.0 #NUM!

273 n.a. n.a. 0.0 #NUM!

273 n.a. n.a. 0.0 #NUM!

360 n.a. n.a. 0.0 #NUM!

360 n.a. n.a. 0.0 #NUM!

Data obtained from Tables 10-11, pages 55-58 of the study report.

n.d. = not detected

n.a. = not analyzed

Note: Chart includes data throughout Day 121. Intervals thereafter were not includeded.

Calculated Half Life = 56 days

SUMMARY OUTPUT

Regression Statistics

Multiple R 0.960214158

R Square 0.922011229

Adjusted R Square 0.919011661

Standard Error 0.141038458

Observations 28

ANOVA

df SS MS F Significance F

Regression 1 6.114382256 6.114382256 307.381329 6.35367E-16

Residual 26 0.517188013 0.019891847

Total 27 6.631570269

Coefficients Standard Error t Stat P-value Lower 95% Upper 95%Lower 95.0%Upper 95.0%

Intercept 4.364172279 0.031894975 136.8294637 1.08819E-38 4.29861122 4.429733 4.298611 4.429733

X Variable 1 -0.012431462 0.000709061 -17.53229389 6.35367E-16 -0.01388896 -0.01097 -0.01389 -0.01097

Total System Analysis

% Applied Radioactivity

y = -0.0124x + 4.3642

R2 = 0.922

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

5.0

0 20 40 60 80 100 120 140

ln (% Applied Radioactivity)

Time (days)

Total Residues
106

Appendix C – Trinexapac-Ethyl and Its Major and Minor Degradates

Code Name/ 

Synonym Chemical Name Chemical Structure Study Type MRID Maximum %AR (day)

Final %AR 

(study length)

PARENT

TrinexapacEthyl

CGA-163935

CSAA15220

IUPAC Name: Ethyl (RS)-4-

cyclopropyl(hydroxy)methylene3,5-dioxocyclohexanecarboxylate

CAS Name: [4(Cyclopropyl-αhydroxy-methylene)-3,5-dioxocyclohexanecarboxylic acid 

ethylester]

CAS Number: 95266-40-3

Formula: C13H16O5

MW: 252.26 g/mol

SMILES: C(O)(C2CC2)=C1C(=O)CC(C(=

O)OCC)CC1=O

Hydrolysis pH 5

41563930

stable

Hydrolysis pH 7 stable

Hydrolysis pH 9 8.6 (30 days)

Aqueous Photolysis 46809302 13.0 (15 days)

Soil Photolysis 42081406 2.4 (30 days)

Aerobic Soil Metabolism 46809303 NA (80 days)

41563933 NA (90 days)

Anaerobic Soil Metabolism 41563933 NA (90 days)

Aerobic Aquatic Metabolism 46809304 NA (111 days)

Anaerobic Aquatic Metabolism 48043712 NA (360 days)

Terrestrial Field Dissipation 48043710 < LOQ (330 days)

48043711 < LOQ (252 days)

MAJOR (>10%) TRANSFORMATION PRODUCTS

Trinexapac-Acid

CGA-179500

IUPAC Name: 4-

[Cyclopropyl(hydroxyl)methylene

]-3,5-dioxocyclohexanecarboxylic 

acid

CAS Name: 4-(Cyclopropyl-αhydroxy-methylene)-3,5-dioxocyclohexanecarboxylic acid

SMILES: C(O)(C2CC2)=C1C(=O)CC(C(=

O)O)CC1=O 

Hydrolysis (Ester study) pH 9 41563930 90.69 (30 days) 90.69 (30 days)

HO

O

O

O

O C

H2

CH3

HO

O

O

O

OH
107

Code Name/ 

Synonym Chemical Name Chemical Structure Study Type MRID Maximum %AR (day)

Final %AR 

(study length)

Hydrolysis (Acid study) pH 5

46809301

-- 43.5 (91 days)

Hydrolysis (Acid study) pH 7 -- stable

Hydrolysis (Acid study) pH 9 -- stable

Aqueous Photolysis 46809302 5.1 (10 days) 1.4 (15 days)

Soil Photolysis 42081406 52.2 (7 days) --

Aerobic Soil Metabolism 46809303 43.5 (1 day)

LD (28 days)

NA (80 days)

Aerobic Aquatic Metabolism 46809304 70.9 (14 days)

LD (20 days)

NA (111 days)

Anaerobic Aquatic Metabolism 48043712 87.8 (18 days)

LD (182 days)

NA (360 days)

Terrestrial Field Dissipation 48043710 192 ppm (265 d) < LOQ (330 days)

48043711 40 ppm (0 d) < LOQ (252 days)

CGA-313458 IUPAC Name: 2-(4-Cyclopropyl2,4-dioxo-butyl)-succinic acid

Hydrolysis (Acid study) pH 5 46809301 21.5 (90 days) 21.5 (90 days)

Aqueous Photolysis 46809302 6.3 (15 days) 6.3 (15 days)

Unidentified

M3

Hydrolysis (Acid study) pH 5 46809301 34.6 (90 days) 34.6 (90 days)

Open Chain 

Cyclohexane 

Ring 

(Cimectacarb)

Soil Photolysis 42081406 11.5 (7 days) --

Carbon

Dioxide

CAS Number: 124-38-9

Formula: CO2

MW: 44.1 g/mol

Aqueous Photolysis 46809302 19.9 (15 days) 19.9 (15 days)

Aerobic Soil Metabolism 46809303 71.0 (80 days) 71.0 (80 days)

41563933 56.0 (90 days) 56.0 (90 days)

Aerobic Aquatic Metabolism 46809304 72.8 (83 days) 69.0 (111 days)

Anaerobic Aquatic Metabolism 48043712 84.5 (30 days) 84.5 (30 days)

Unextractable 

Residues

Aerobic Soil Metabolism 46809303 69.0 (0.25 days) 27.7 (80 days)

Aerobic Aquatic Metabolism 46809304 38.9 (55 days) 26.8 (111 days)

Anaerobic Aquatic Metabolism 48043712 63.5 (91 days) 15.1 (360 days)

OH

O O O

O OH

O C O
108

Code Name/ 

Synonym Chemical Name Chemical Structure Study Type MRID Maximum %AR (day)

Final %AR 

(study length)

MINOR (<10%) TRANSFORMATION PRODUCTS

Unidentified 

Unknowns

Aqueous Photolysis 46809302 9.7 (15 days) 9.7 (15 days) 1

Soil Photolysis 42081406 -- < 4 (30 days) 2

Aerobic Aquatic Metabolism 46809304 4.5 (20 days)

LD (20 days)

NA (111 days) 

NA = Not Analyzed

LD = Last Detected

LOQ = Limit of Quantitation

1 Unidentified unknowns consists of five components ranging from 0.5 – 9.7% of the applied radioactivity at study termination. 2 Unidentified unknowns consisted of two components consisting of < 4% of the applied radioactivity at study termination.
109

Appendix D – ECOTOX Literature Search

Papers That Were Accepted

1. Alvarez, R. C. F.; Crusciol, C. A. C.; Nascente, A. S.; Rodrigues, J. D., and Habermann, G. Gas 

Exchange Rates, Plant Height, Yield Components, and Productivity of Upland Rice as Affected 

by Plant Regulators. GRO,PHY,POP,REPSOIL,ENV; 2012; 47, (10): 1455-1461. 

Rec #: 480

Call Number: LITE EVAL CODED (TXE), OK (PBZ)

Notes: EcoReference No.: 159810

Chemical of Concern: MQC,PBZ,TXE; rejected because endpoint is not used in risk 

assessments

2. Arghavani, M.; Kafi, M.; Babalar, M.; Naderi, R.; Hoque, M. A., and Murata, Y. Improvement of Salt 

Tolerance in Kentucky Bluegrass by Trinexapac-Ethyl. 

BCM,GRO,PHYSOIL,ENV,MIXTURE; 2012; 47, (8): 1163-1170. 

Rec #: 490

Call Number: LITE EVAL CODED (TXE), OK (1Major ions,Halides,NaCl)

Notes: EcoReference No.: 159794

Chemical of Concern: 1Major ions,Halides,NaCl,TXE; rejected because endpoint is not used in 

risk assessments

3. Atkinson, J. L. Response of Warm Season Turfgrasses to Reduced Light Environments. 

BCM,GRO,PHY,POPSOIL,ENV; 2010: 94 p. (UMI# 1488281) (Publ in part as Ecoref 159652). 

Rec #: 420

Call Number: LITE EVAL CODED (TXE)

Notes: EcoReference No.: 159822

Chemical of Concern: TXE; rejected because endpoint was non-definitive.

4. Atkinson, J. L.; McCarty, L. B.; Liu, H.; Faust, J., and Toler, J. E. Diamond Zoysiagrass Golf Green 

Response to Reduced Light Environments with the Use of Trinexapac-Ethyl. 

BCM,PHY,POPSOIL,ENV; 2012; 104, (4): 847-852. 

Rec #: 240

Call Number: LITE EVAL CODED (TXE)

Notes: EcoReference No.: 159652

Chemical of Concern: TXE; rejected because endpoint was non-definitive.

5. Baldwin, C. M.; Liu, H.; McCarty, L. B.; Luo, H., and Toler, J. E. 'L-93' Creeping Bentgrass Putting 

Green Responses to Various Winter Light Intensities in the Southern Transition Zone. 

BCM,PHY,POPSOIL,ENV; 2009; 44, (6): 1751-1756. 

Rec #: 500

Call Number: LITE EVAL CODED (TXE)

Notes: EcoReference No.: 159811

Chemical of Concern: TXE; rejected because endpoint is not used in risk assessments.

6. ---. Nitrogen and Plant Growth Regulator Influence on 'Champion' Bermudagrass Putting Green Under 

Reduced Sunlight. BCM,PHY,POPSOIL,ENV,MIXTURE; 2009; 101, (1): 75-81. 

Rec #: 430

Call Number: LITE EVAL CODED (TXE)

Notes: EcoReference No.: 159795

Chemical of Concern: TXE,Urea; rejected because endpoint is non-definitive.
110

7. Beasley, J. S. and Branham, B. E. Trinexapac-Ethyl and Paclobutrazol Affect Kentucky Bluegrass 

Single-Leaf Carbon Exchange Rates and Plant Growth. GRO,PHYSOIL,ENV; 2007; 47, (1): 

132-138. 

Rec #: 10

Call Number: LITE EVAL CODED (TXE), OK (PBZ)

Notes: EcoReference No.: 159777

Chemical of Concern: PBZ,TXE; rejected because endpoint is not used in risk assessments.

8. Beasley, J. S.; Branham, B. E., and Arthur Spomer, L. Plant Growth Regulators Alter Kentucky 

Bluegrass Canopy Leaf Area and Carbon Exchange. ACC,GRO,PHY,POPSOIL,ENV; 2007; 

47, (2): 757-766. 

Rec #: 20

Call Number: LITE EVAL CODED (TXE), OK (PBZ)

Notes: EcoReference No.: 159778

Chemical of Concern: PBZ,TXE; rejected because endpoints were higher than existing toxicity 

data.

9. Bell, G. E.; Odorizzi, E., and Danneberger, T. K. Reducing Populations of Annual Bluegrass and 

Roughstalk Bluegrass in Creeping Bentgrass Fairways: A Nutritional Approach. 

PHY,POPSOIL,ENV,MIXTURE; 1999; 13, (4): 829-834. 

Rec #: 30

Call Number: LITE EVAL CODED (BS,TXE), OK (FeRS)

Notes: EcoReference No.: 152008

Chemical of Concern: 1Major ions,BS,EFS,FeRS,MgSO4,MgSO4s,TXE; rejected because 

endpoints were higher than existing toxicity data.

10. Bian, X.; Merewitz, E., and Huang, B. Effects of Trinexapac-Ethyl on Drought Responses in Creeping 

Bentgrass Associated with Water Use and Osmotic Adjustment. BCM,PHY,POPSOIL,ENV; 

2009; 134, (5): 505-510. 

Rec #: 440

Call Number: LITE EVAL CODED (TXE)

Notes: EcoReference No.: 159812

Chemical of Concern: TXE; rejected because endpoint is not used in risk assessments.

11. Burpee, L. L.; Green, D. E., and Stephens, S. L. Interactive Effects of Plant Growth Regulators and 

Fungicides on Epidemics of Dollar Spot in Creeping Bentgrass. GRO,POPENV; 1996; 80, 

(11): 1245-1250. 

Rec #: 190

Call Number: LITE EVAL CODED (FPD,PBZ,TXE)

Notes: EcoReference No.: 95309

Chemical of Concern: FPD,PBZ,TXE; not used because fungi are not assessed.

12. Caldas, L. S.; Machado, L. L.; Caldas, S. C.; Campos, M. L.; Caldas, J. A.; Pharis, R. P., and PereiraNetto, A. B. Growth-Active Gibberellins Overcome the Very Slow Shoot Growth of Hancornia 

speciosa, an Important Fruit Tree from the Brazilian "Cerrado". GRO. [Pereira-Netto, AB] 

Univ Fed Parana, Dept Bot SCB, Ctr Politecn, BR-81531970 Curitiba, Parana, Brazil//: 

SOIL,TOP; 2009; 23, (6): 1229-1235. 

Rec #: 450

Call Number: LITE EVAL CODED (TXE)

Notes: EcoReference No.: 159813

Chemical of Concern: ACM,GIB,TXE; rejected because endpoints were higher than existing 

toxicity data.

13. Chen, C. M. The Geographic Distribution, Genetic Structure and Cultural Management of Waitea 

circinata Var. Circinata, the Causal Agent of Brown Ring Patch Isolated from Turf Grass in the 

U.S. BCM,POPSOIL,ENV,MIXTURE; 2011: 123 p. (UMI# 3477392). 
111

Rec #: 410

Call Number: LITE EVAL CODED (TXE), OK (AZX)

Notes: EcoReference No.: 159820

Chemical of Concern: AZX,NHSO4,TXE,Urea; rejected because endpoints were higher than 

existing toxicity data.

14. Ciba-Geigy Ltd. Initial: Submission: Pilot 7-Week Oral Feeding Study with Cimectacarb in Dogs with 

Attachments and Cover Letter Dated 073192. BCM,BEH,CEL,GRO,MORORAL; 1992: 389 p. 

(NTIS/OTS0543163). 

Rec #: 180

Call Number: LITE EVAL CODED (TXE)

Notes: EcoReference No.: 100765

Chemical of Concern: TXE; rejected because endpoints were higher than existing toxicity data.

15. Ervin, E. H. and Koski, A. J. Trinexapac-Ethyl Increases Kentucky Bluegrass Leaf Cell Density and 

Chlorophyll Concentration. BCM,CEL. Department of Horticulture and Landscape 

Architecture,Colorado State University,Fort Collins,CO//: SOIL,ENV; 2001; 36, (4): 787-789. 

Rec #: 590

Call Number: LITE EVAL CODED (TXE)

Notes: EcoReference No.: 159848

Chemical of Concern: TXE; rejected because endpoint is not used in risk assessments.

16. Ervin, E. H. and Ok, C. Influence of Plant Growth Regulators on Suppression and Quality of 'Meyer' 

Zoysiagrass. PHY,POPSOIL,ENV; 2001; 19, (2): 57-60. 

Rec #: 300

Call Number: LITE EVAL CODED (TXE), OK (EPH)

Notes: EcoReference No.: 159814

Chemical of Concern: EPH,TXE; rejected because endpoints were higher than existing toxicity 

data.

17. Ervin, E. H. and Zhang, X. Influence of Sequential Trinexapac-Ethyl Applications on Cytokinin Content 

in Creeping Bentgrass, Kentucky Bluegrass, and Hybrid Bermudagrass. 

BCM,GRO,PHYSOIL,ENV; 2007; 47, (5): 2145-2151. 

Rec #: 560

Call Number: LITE EVAL CODED (TXE)

Notes: EcoReference No.: 159896

Chemical of Concern: TXE; rejected because endpoints are not used in risk assessment.

18. Fagerness, M. J. and Penner, D. Evaluation of V-10029 and Trinexapac-Ethyl for Annual Bluegrass 

Seedhead Suppression and Growth Regulation of Five Cool-Season Turfgrass Species. 

POP,REP. M.J. Fagerness, Department of Crop and Soil Sciences, Michigan State University, 

East Lansing, MI 48824-1325////: SOIL,ENV; 1998; 12, (3): 436-440. 

Rec #: 40

Call Number: LITE EVAL CODED (TXE)

Notes: EcoReference No.: 159849

Chemical of Concern: TXE; rejected because endpoints are not used in risk assessments.

19. ---. Spray Application Parameters that Influence the Growth Inhibiting Effects of Trinexapac-Ethyl. 

POP. salemka@pilot.msu.edu//D. Penner, Michigan State Univ., Dep. of Crop and Soil 

Sciences, East Lansing, MI 48824-1325////: SOIL,ENV,MIXTURE; 1998; 38, (4): 1028-1035. 

Rec #: 210

Call Number: LITE EVAL CODED (TXE), NO MIXTURE (CaAC), OK (SXD)

Notes: EcoReference No.: 66135

Chemical of Concern: CaAC,NHSO4,SXD,TXE; rejected because endpoints are not used in risk 

assessments.
112

20. Fagerness, M. J. and Yelverton, F. H. Plant Growth Regulator and Mowing Height Effects on Seasonal 

Root Growth of Penncross Creeping Bentgrass. POPSOIL,ENV,MIXTURE; 2001; 41, (6): 

1901-1905. 

Rec #: 200

Call Number: LITE EVAL CODED (PBZ,TXE)

Notes: EcoReference No.: 111282

Chemical of Concern: PBZ,TXE; rejected because endpoints are higher than existing toxicity 

data.

21. Fan, G.; Bian, X.; Li, H.; Meng, Z., and Liu, S. Growth Responses of Kentucky Bluegrass (Poa pratensis 

L.) to Trinexapac-Ethyl Applied in Spring and Autumn. BCM,GRO,POP. Springer Science & 

Business Media//: SOIL,ENV; 2009; 3, (2): 186-189. 

Rec #: 400

Call Number: LITE EVAL CODED (TXE)

Notes: EcoReference No.: 159815

Chemical of Concern: TXE; rejected because endpoint is not used in risk assessments.

22. Han, S.; Fermanian, T. W.; Juvik, J. A., and Spomer, L. A. Total Nonstructural Carbohydrate Storage in 

Creeping Bentgrass Treated with Trinexapac-Ethyl. BCM,PHY. Gyeonggido Agricultural 

Research and Extension Services,Taean-eup, Hwasung City, Gyeonggido,S. Korea//: 

SOIL,ENV; 2004; 39, (6): 1461-1464. 

Rec #: 540

Call Number: LITE EVAL CODED (TXE)

Notes: EcoReference No.: 159857

Chemical of Concern: TXE; rejected because endpoints are not used in risk assessments.

23. Han, S. W.; Fermanian, T. W.; Juvik, J. A., and Spomer, L. A. Growth Retardant Effects on Visual 

Quality and Nonstructural Carbohydrates of Creeping Bentgrass. BCM,PHYSOIL,ENV; 1998; 

33, (7): 1197-1199. 

Rec #: 50

Call Number: LITE EVAL CODED (TXE), NO EFFECT (FSTAL), OK (FPD,PBZ)

Notes: EcoReference No.: 159876

Chemical of Concern: FPD,FSTAL,PBZ,TXE; rejected because endpoints are not used in risk 

assessments.

24. Hare, M. D.; Lunpha, A., and Phengphet, S. Effect of Foliar Applications of Trinexapac-Ethyl Plant 

Growth Regulator on Seed Yield in Brachiaria Hybrid cv. Mulato II and Paspalum atratum. 

GRO,POP,REPSOIL,ENV; 2008; 42, (3): 181-187. 

Rec #: 460

Call Number: LITE EVAL CODED (TXE)

Notes: EcoReference No.: 159816

Chemical of Concern: TXE; rejected because endpoint not used in risk assessments.

25. Heckman, N. L.; Horst, G. L.; Gaussoin, R. E., and Tavener, B. T. Trinexapac-Ethyl Influence on Cell 

Membrane Thermostability of Kentucky Bluegrass Leaf Tissue. PHY. Department of 

Agronomy and Horticulture,University of Nebraska,Lincoln,NE//: SOIL,ENV; 2002; 92, (2): 

183-186. 

Rec #: 580

Call Number: LITE EVAL CODED (TXE)

Notes: EcoReference No.: 159878

Chemical of Concern: TXE; rejected because endpoints are not used in risk assessment.

26. Heckman, N. L.; Horst, G. L.; Gaussoin, R. E., and Young, L. J. Heat Tolerance of Kentucky Bluegrass 

as Affected by Trinexapac-Ethyl. PHY. Department of Agronomy and Horticulture,University 

of Nebraska-Lincoln,Lincoln,NE//: SOIL,ENV; 2001; 36, (2): 365-367. 

Rec #: 600
113

Call Number: LITE EVAL CODED (TXE)

Notes: EcoReference No.: 159847

Chemical of Concern: TXE; rejected because endpoint not used in risk assessments.

27. Inguagiato, J. C.; Murphy, J. A., and Clarke, B. B. Anthracnose Severity on Annual Bluegrass Influenced 

by Nitrogen Fertilization, Growth Regulators, and Verticutting. 

PHY,POP,REPSOIL,ENV,MIXTURE; 2008; 48, 1595-1607. 

Rec #: 150

Call Number: LITE EVAL CODED (TXE), NO EFFECT (BFT,CPY,CTN,FTL,VCZ), OK 

(MFD)

Notes: EcoReference No.: 118057

Chemical of Concern: BDC,BFT,BSC,CPY,CTN,FTL,MFD,TXE,VCZ; rejected because 

endpoints are higher than existing toxicity data.

28. Isgrigg III, J. Ecological Adaptations of Annual Bluegrass to Plant Growth Regulators and Herbicides. 

BCM,GRO,PHY,POPSOIL,ENV,MIXTURE; 1999: 162 p. (UMI #9960156). 

Rec #: 160

Call Number: LITE EVAL CODED 

(ATZ,DQT,FPD,FRM,GYP,OYZ,PBZ,PDM,PRM,PZM,SFZ,SZ,TXE), NO MIXTURE 

(NONA,PCZ,PPCP,PPCP2011)

Notes: EcoReference No.: 121125

Chemical of Concern: 

ATZ,BFL,CPZ,DQT,DTP,FPD,FRM,GYP,MBZ,NONA,ODZ,OYZ,PBZ,PCZ,PDM,PPCP,PPC

P2011,PRM,PZM,SFZ,SZ,TXE; rejected because rejected because endpoint not used in risk 

assessments.

29. Jiang, H. and Fry, J. Drought Responses of Perennial Ryegrass Treated with Plant Growth Regulators. 

GRO,PHYSOIL,ENV; 1998; 33, (2): 270-273. 

Rec #: 60

Call Number: LITE EVAL CODED (TXE), OK (EPH,MFD,PBZ)

Notes: EcoReference No.: 156115

Chemical of Concern: EPH,MFD,PBZ,TXE; rejected because endpoint is higher than existing 

toxicity data.

30. Johnson, B. J. Response of Bahiagrass (Paspalum notatum) to Plant Growth Regulators. 

GRO,PHY,POP. Univ. Ga., Ga. Stn., Griffin, Ga. 30223-1797////: SOIL,ENV,MIXTURE; 1990; 

4, (4): 895-899. 

Rec #: 70

Call Number: LITE EVAL CODED (GYPI,GYPS,TXE), NO MIXTURE 

(24D,24DXY,FPD,PBZ), OK (MFD)

Notes: EcoReference No.: 156191

Chemical of Concern: 24D,24DXY,FPD,GYPI,GYPS,IZT,MFD,PBZ,TXE; rejected because 

endpoint is not used in risk assessments.

31. ---. Response of Centipedegrass (Eremochloa ophiuroides) to Plant Growth Regulators. GRO,PHY,POP. 

Univ. Ga., Georgia Stn., Griffin, Calif. 30223-1797////: SOIL,ENV,MIXTURE; 1992; 6, (1): 

113-118. 

Rec #: 80

Call Number: LITE EVAL CODED (TXE), NO MIXTURE (MFD), OK (PBZ)

Notes: EcoReference No.: 159875

Chemical of Concern: MFD,PBZ,TXE; rejected because endpoint is not used in risk 

assessments.

32. Keever, G. J. and Olive, J. W. Effects of Primo Rate and Application Volume on Selected Herbaceous 

and Woody Landscape Plants. GRO,PHY. Dep. Hortic., Ala. Agric. Experiment Station, 

Auburn Univ., Auburn, AL 36849//: SOIL,ENV; 1998; 16, (2): 114-117. 
114

Rec #: 510

Call Number: LITE EVAL CODED (TXE)

Notes: EcoReference No.: 159897

Chemical of Concern: TXE; rejected because endpoint is not in the correct units.

33. Kreuser, W. C. and Soldat, D. J. A Growing Degree Day Model to Schedule Trinexapac-Ethyl 

Applications on Agrostis stolonifera Golf Putting Greens. POP. American Society of 

Agronomy//: SOIL,ENV; 2011; 51, (5): 2228-2236. 

Rec #: 370

Call Number: LITE EVAL CODED (TXE), NO EFFECT (CTN)

Notes: EcoReference No.: 159855

Chemical of Concern: CTN,TXE; rejected because endpoint is not used in risk assessments.

34. Lowe, D. B. and Whitwell, T. Plant Growth Regulators Alter the Growth of 'Tifway' Bermudagrass 

(Cynodon transvaalensis x C. dactylon) and Selected Turfgrass Weeds. GRO,POPSOIL,ENV; 

1999; 13, (1): 132-138. 

Rec #: 90

Call Number: LITE EVAL CODED (TXE), OK (FPD,PBZ)

Notes: EcoReference No.: 159874

Chemical of Concern: FPD,PBZ,TXE; rejected because endpoint is higher than existing toxicity 

data.

35. McCann, S. E. and Huang, B. Drought Responses of Kentucky Bluegrass and Creeping Bentgrass as 

Affected by Abscisic Acid and Trinexapac-Ethyl. BCM,GRO,PHYSOIL,ENV; 2008; 133, (1): 

20-26. 

Rec #: 470

Call Number: LITE EVAL CODED (TXE), OK (ASA)

Notes: EcoReference No.: 159838

Chemical of Concern: ASA,TXE; rejected because endpoint is higher than existing toxicity 

data.

36. McCarty, L. B.; Weinbrecht, J. S.; Toler, J. E., and Miller, G. L. St. Augustinegrass Response to Plant 

Growth Retardants. GRO,PHY,POPSOIL,ENV; 2004; 44, (4): 1323-1329. 

Rec #: 310

Call Number: LITE EVAL CODED (TXE), OK (FPD,MFD,PBZ)

Notes: EcoReference No.: 159859

Chemical of Concern: FPD,IAZ,MFD,PBZ,TXE; rejected because endpoints are higher than 

existing toxicity data.

37. McCullough, P. E.; Hart, S. E., and Lycan, D. W. Plant Growth Regulator Regimens Reduce Poa annua 

Populations in Creeping Bentgrass. PHY,POP. mccullough@aesop.rutgers.edu//: 

SOIL,ENV,MIXTURE; 2005: 6 p. (doi.org/10.1094/ATS-2005-0304-01-RS). 

Rec #: 320

Call Number: LITE EVAL CODED (TXE), OK (PBZ)

Notes: EcoReference No.: 159832

Chemical of Concern: PBZ,TXE; rejected because endpoints are higher than existing toxicity 

data.

38. McCullough, P. E.; Liu, H., and McCarty, L. B. Ethephon and Gibberellic Acid Inhibitors Influence 

Creeping Bentgrass Putting Green Quality and Ball Roll Distances. PHYSOIL,ENV; 2005; 40, 

(4): 1902-1903. 

Rec #: 170

Call Number: LITE EVAL CODED (TXE), OK (EPH,FPD,PBZ)

Notes: EcoReference No.: 116859

Chemical of Concern: EPH,FPD,PBZ,TXE; Not used because endpoint was non-definitive.
115

39. ---. Mowing Operations Influence Creeping Bentgrass Putting Green Ball Roll Following Plant Growth 

Regulator Applications. PHYSOIL,ENV; 2005; 40, (2): 471-474. 

Rec #: 100

Call Number: LITE EVAL CODED (TXE), OK (EPH,FPD,PBZ)

Notes: EcoReference No.: 159831

Chemical of Concern: EPH,FPD,PBZ,TXE; Rejected because the endpoint is the same as 

existing toxicity data.

40. McCullough, P. E.; Liu, H.; McCarty, L. B., and Toler, J. E. Ethephon and Trinexapac-Ethyl Influence 

Creeping Bentgrass Growth, Quality, and Putting Green Performance. PHY,POP. 

mccullough@aesop.rutgers.edu//: SOIL,ENV; 2006: 7 p. (doi.org/10.1094/ATS-2006-0324-01-

RS). 

Rec #: 330

Call Number: LITE EVAL CODED (TXE), OK (EPH)

Notes: EcoReference No.: 159833

Chemical of Concern: EPH,TXE; rejected because endpoint is higher than existing toxicity data.

41. McCullough, P. E.; McCarty, L. B.; Liu, H., and Whitwell, T. Response of 'TifEagle' Bermudagrass 

(Cynodon dactylon x Cynodon transvaalensis) to Ethephon and Trinexapac-Ethyl. 

GRO,PHY,POPSOIL,ENV,MIXTURE; 2005; 19, (2): 251-254. 

Rec #: 110

Call Number: LITE EVAL CODED (TXE), WEEDS (EPH)

Notes: EcoReference No.: 159582

Chemical of Concern: EPH,TXE; rejected because the endpoint is not used in risk assessments.

42. Na, C. I.; Hamayun, M.; Khan, A. L.; Kim, Y. H.; Choi, K. I.; Kang, S. M.; Kim, S. I.; Kim, J. T.; Won, 

J. G., and Lee, I. J. Influence of Prohexadione-Calcium, Trinexapac-Ethyl and Hexaconazole on 

Lodging Characteristic and Gibberellin Biosynthesis of Rice (Oryza sativa L.). 

BCM,GRO,PHY. School of Applied Biosciences, Kyungpook National University, Daegu 701-

702, South Korea,//: SOIL,ENV,MIXTURE; 2011; 10, (61): 13097-13106.

Rec #: 360

Call Number: LITE EVAL CODED (TXE)

Notes: EcoReference No.: 159839

Chemical of Concern: HCZ,TXE; rejected because endpoints are not used in risk assessments.

43. Nangle, E. J.; Gardner, D. S.; Metzger, J. D.; Street, J. R., and Danneberger, T. K. Impact of Nitrogen 

Source and Trinexapac-Ethyl Application on Creeping Bentgrass (Agrostis stolonifera L.) 

Physiology Under Neutral Shade, Deciduous Tree Shade, and Full Sunlit Conditions. 

BCM,PHY,POPSOIL,ENV,MIXTURE; 2012; 47, (7): 936-942. 

Rec #: 250

Call Number: LITE EVAL CODED (TXE), NO EFFECT 

(AZX,CTN,IMC,PCZ,PPCP,PPCP2011)

Notes: EcoReference No.: 159809

Chemical of Concern: AZX,CTN,IMC,NHSO4,PCZ,PPCP,PPCP2011,TXE,Urea; rejected 

because endpoint is not used in risk assessments.

44. Pessarakli, M.; Marcum, K. B., and Kopec, D. M. Interactive Effects of Salinity and Primo on the 

Growth of Kentucky Bluegrass. GRO,POPSOIL,ENV; 2006; 4, (1): 325-327. 

Rec #: 570

Call Number: LITE EVAL CODED (TXE)

Notes: EcoReference No.: 159879

Chemical of Concern: TXE; rejected because endpoint is higher than existing toxicity data.

45. Putman, A. I. and Kaminski, J. E. Mowing Frequency and Plant Growth Regulator Effects on Dollar Spot 

Severity and on Duration of Dollar Spot Control by Fungicides. POP. Department of Crop and 

Soil Sciences, The Pennsylvania State University, University Park 16802, USA, American 
116

Phytopathological Society//: ENV,MIXTURE; 2011; 95, (11): 1433-1442. 

Rec #: 350

Call Number: LITE EVAL CODED (TXE), OK (PBZ), TARGET2012 

(CTN,IPD,PCZ,PPCP,PPCP2011)

Notes: EcoReference No.: 159841

Chemical of Concern: BSC,CTN,IPD,PBZ,PCZ,PPCP,PPCP2011,TXE; rejected because 

endpoint is not used in risk assessments.

46. Rajala, A.; Peltonen-Sainio, P.; Onnela, M., and Jackson, M. Effects of Applying Stem-Shortening Plant 

Growth Regulators to Leaves on Root Elongation by Seedlings of Wheat, Oat and Barley: 

Mediation by Ethylene. BCM,GROSOIL,ENV; 2002; 38, (1): 51-59. 

Rec #: 120

Call Number: LITE EVAL CODED (TXE), NO ENDPOINT (CQTC,ETL), OK (EPH)

Notes: EcoReference No.: 159854

Chemical of Concern: CQTC,EPH,ETL,TXE; rejected because endpoint is higher than existing 

toxicity data.

47. Ramoutar, D.; Cowles, R. S.; Requintina, E. Jr., and Alm, S. R. Synergism Between Demethylation 

Inhibitor Fungicides or Gibberellin Inhibitor Plant Growth Regulators and Bifenthrin in a 

Pyrethroid-Resistant Population of Listronotus maculicollis (Coleoptera: Curculionidae). 

MORENV,MIXTURE,TOP; 2010; 103, (5): 1810-1814. 

Rec #: 230

Call Number: LITE EVAL CODED (BFT,FPD,FRM,PCZ,PPCP,PPCP2011,TXE), NO 

MIXTURE (PBZ)

Notes: EcoReference No.: 152401

Chemical of Concern: BFT,FPD,FRM,PBZ,PCZ,PPCP,PPCP2011,TXE; rejected because units 

are not useful.

48. Rolston, M. P.; Archie, W. J., and Rumball, W. Branched Inflorescence Perennial Ryegrass (Lolium 

perenne L.)-Seed Yield Evaluated in Field Trials and Response to Nitrogen and TrinexapacEthyl Plant Growth Regulator. GRO,POP. AgResearch Ltd,Lincoln,N. Z//: SOIL,ENV; 2005; 

48, (1): 87-92. 

Rec #: 530

Call Number: LITE EVAL CODED (TXE)

Notes: EcoReference No.: 159850

Chemical of Concern: TXE; rejected because endpoints are not used for risk assessments.

49. Rolston, P.; Trethewey, J.; Chynoweth, R., and McCloy, B. Trinexapac-Ethyl Delays Lodging and 

Increases Seed Yield in Perennial Ryegrass Seed Crops. GRO,POP. Taylor & Francis Ltd.//: 

SOIL,ENV,MIXTURE; 2010; 53, (4): 403-406. 

Rec #: 380

Call Number: LITE EVAL CODED (TXE), NO CONC (CQTC), NO MIXTURE (CQTC)

Notes: EcoReference No.: 159781

Chemical of Concern: CQTC,TXE; rejected because toxicity data are higher than existing data.

50. Roohollahi, I. and Kafi, M. Salinity and Trinexapac-Ethyl Effects on Seed Reserve Utilization and 

Seedling Growth of Two Lolium perenne Cultivars. BCM,GRO,REPSOIL,ENV,MIXTURE; 

2010; 51, (2): 78-82. 

Rec #: 260

Call Number: LITE EVAL CODED (TXE), OK (1Major ions,Halides,NaCl)

Notes: EcoReference No.: 159856

Chemical of Concern: 1Major ions,Halides,NaCl,TXE; rejected because endpoint is higher than 

existing toxicity data.

51. Roohollahi, I.; Kafi, M., and Naderi, R. Drought Reaction and Rooting Characteristics in Response to 

Plant Growth Regulators on Poa pratensis cv. Barimpala. PHY,POP. World Food, RD Ltd., 
117

Meri-Rastilantie 3 C Helsinki FIN-00980 Finland, [mailto:Publisher@world-food.net], 

[URL:http://www.world-food.net]//: SOIL,ENV; 2010; 8, (1): 285-288. 

Rec #: 390

Call Number: LITE EVAL CODED (TXE), OK (PBZ)

Notes: EcoReference No.: 159843

Chemical of Concern: PBZ,TXE; rejected because endpoints are higher than existing toxicity 

data.

52. Severmutlu, S.; Mutlu, N.; Gurbuz, E.; Shearman, R. C., and Riordan, T. P. Effects of Seasonal 

Trinexapac-Ethyl Application on Warm-Season Turfgrass Species Growth Under Mediterranean 

Environment. GRO,POP. [Severmutlu, S] Akdeniz Univ, Dept Landscape Architecture, TR07058 Antalya, Turkey [Mutlu, N] Akdeniz Univ, Dept Agr Biotechnol, TR-07058 Antalya, 

Turkey [Gurbuz, E] Bati Akdeniz Agr Res Inst, Antalya, Turkey//: SOIL,ENV; 2012; 77, (6): 

279-287. 

Rec #: 270

Call Number: LITE EVAL CODED (TXE)

Notes: EcoReference No.: 159782

Chemical of Concern: TXE; rejected because endpoints are not used in risk assessment.

53. Spinelli, F.; Costa, G.; Vanneste, J. L.; Cornish, D. A., and Yu, J. Growth-Regulating 

Acylcyclohexanediones, Trinexapac-Ethyl and Prohexadione-Calcium Decrease Blossom Blight 

Incidence in Pome Fruits. PHY. Dipartimento di Colture Arboree,Universita di 

Bologna,Bologna,Italy//: SOIL,ENV; 2006; 704, 245-248. 

Rec #: 520

Call Number: LITE EVAL CODED (TXE)

Notes: EcoReference No.: 159881

Chemical of Concern: TXE; rejected because endpoints are not used in risk assessment.

54. Spinelli, F.; Rademacher, W.; Sabatini, E., and Costa, G. Reduction of Scab Incidence (Venturia 

inaequalis) in Apple with Prohexadione-Ca and Trinexapac-Ethyl, Two Growth Regulating 

Acylcyclohexanediones. BCM,GRO,POP,REPSOIL,ENV,MIXTURE; 2010; 29, (7): 691-698. 

Rec #: 220

Call Number: LITE EVAL CODED (TXE), OK (CQTC,MEM,PBZ)

Notes: EcoReference No.: 152402

Chemical of Concern: CQTC,KRSM,MEM,PBZ,TXE; rejected because endpoints are higher 

than exisiting toxicity data.

55. Tan, Z. G. and Qian, Y. L. Light Intensity Affects Gibberellic Acid Content in Kentucky Bluegrass. 

BCM,GRO,POP. Dept. of Horticulture and Landscape Architecture,Colorado State Univ.,Fort 

Collins,CO//: SOIL,ENV; 2003; 38, (1): 113-116. 

Rec #: 550

Call Number: LITE EVAL CODED (TXE)

Notes: EcoReference No.: 159858

Chemical of Concern: TXE; rejected because endpoint is not used in risk assessments.

56. Teuton, T. C. Management of Hybrid Bluegrass (Poa arachnifera Torr. x Poa pratensis L.) in the 

Transition Zone. BCM,GRO,PHY,POPSOIL,ENV; 2006: 159 p. (UMI#3214429). 

Rec #: 130

Call Number: LITE EVAL CODED (CLT,QNC,TXE), NO PUBL AS (MTSM,SXD), OK 

(EPH,OYZ,PBZ,PDM,PRM,TFN)

Notes: EcoReference No.: 154952

Chemical of Concern: 

BP,CLT,CSF,DFPM,DTP,EPH,HSF,IAZ,IMQ,MTSM,ODZ,OYZ,PBZ,PDM,PRM,QNC,RIM,

SFS,SXD,TFN,TXE; rejected because endpoint is not used in risk assessments.

57. Wang, X. Y.; Hu, T. M.; Wang, Q. Z.; Tian, L. M.; Zhang, X. L., and Tian, K. Growth of Kentucky 
118

Bluegrass as Influenced by Nitrogen and Trinexapac-Ethyl. 

BCM,GRO,POPSOIL,ENV,MIXTURE; 2009; 8, (12): 1498-1502. 

Rec #: 280

Call Number: LITE EVAL CODED (TXE), NO NUTRIENT (LQN)

Notes: EcoReference No.: 159793

Chemical of Concern: LQN,TXE; rejected because endpoints are not used in risk assessments.

58. Wherley, B. and Sinclair, T. R. Growth and Evapotranspiration Response of Two Turfgrass Species to 

Nitrogen and Trinexapac-Ethyl. GRO,POPSOIL,ENV; 2009; 44, (7): 2053-2057. 

Rec #: 290

Call Number: LITE EVAL CODED (TXE)

Notes: EcoReference No.: 159844

Chemical of Concern: TXE; rejected because endpoints are not used in risk assessments.

59. Xu, C. and Huang, B. Proteins and Metabolites Regulated by Trinexapac-Ethyl in Relation to Drought 

Tolerance in Kentucky Bluegrass. BCM,PHY. Department of Plant Biology and Pathology, 

Rutgers University, New Brunswick, NJ, 08901, USA, Springer Science+Business Media, Van 

Godewijckstraat 30 Dordrecht 3311 GX Netherlands//: SOIL,ENV; 2012; 31, (1): 25-37. 

Rec #: 340

Call Number: LITE EVAL CODED (TXE)

Notes: EcoReference No.: 159853

Chemical of Concern: TXE; rejected because endpoints are not used in risk assessments.

60. Zapiola, M. L.; Chastain, T. G.; Garbacik, C. J.; Silberstein, T. B., and Young III, W. C. TrinexapacEthyl and Open-Field Burning Maximize Seed Yield in Creeping Red Fescue. 

GRO,POPSOIL,ENV; 2006; 98, (6): 1427-1434. 

Rec #: 140

Call Number: LITE EVAL CODED (TXE)

Notes: EcoReference No.: 159860

Chemical of Concern: TXE; rejected because endpoint is higher than existing toxicity data.

Papers That Were Not Accepted

Accepted for EcoTox but not OPP

1. Blundell, C.; Evans, L. T.; King, R. W.; Mander, L. N., and Wood, J. T. Modified Gibberellins Retard 

Growth of Cool-Season Turfgrasses. GRO,PHYSOIL,ENV; 1997; 37, (6): 1878-1883. 

Rec #: 60

Call Number: NO ENDPOINT (TXE)

Notes: EcoReference No.: 159808

Chemical of Concern: GIB,TXE

2. Fagerness, M. J. and Penner, D. 14C-Trinexapac-Ethyl Absorption and Translocation in Kentucky 

Bluegrass. ACCSOIL,ENV,MIXTURE; 1998; 38, (4): 1023-1027. 

Rec #: 210

Call Number: NO CONTROL (TXE), NO ENDPOINT (TXE)

Notes: EcoReference No.: 159769

Chemical of Concern: TXE

3. Fagerness, M. J.; Yelverton, F. H.; Isgrigg III, J., and Cooper, R. J. Plant Growth Regulators and 

Mowing Height Affect Ball Roll and Quality of Creeping Bentgrass Putting Greens. 

PHY,POPSOIL,ENV; 2000; 35, (4): 755-759. 

Rec #: 10

Call Number: NO ENDPOINT (CTN,PBZ,TXE)

Notes: EcoReference No.: 159877

Chemical of Concern: CTN,PBZ,TXE
119

4. Ferrell, J. A.; Murphy, T. R.; Duncan, R. R., and Vencill, W. K. Seashore Paspalum Response to 

Trinexapac-Ethyl and Paclobutrazol. PHY,POPSOIL,ENV; 2003; 38, (4): 605-606. 

Rec #: 20

Call Number: NO ENDPOINT (PBZ,TXE)

Notes: EcoReference No.: 156109

Chemical of Concern: PBZ,TXE

5. Honma, T. An Approach for the Conquest of the Sugi pollinosis Using Plant Growth Regulation. 

BCM,GRO,REP. Research Institute of Innovative Technology for the Earth, Soraku-gun, 

Kyoto, Japan. tamhonma@rite.or.jp//: SOIL,ENV; 2003; 17, (1): 48-50. 

Rec #: 110

Call Number: NO ENDPOINT (TXE)

Notes: EcoReference No.: 159818

Chemical of Concern: TXE

6. Inguagiato, J. C.; Murphy, J. A., and Clarke, B. B. Anthracnose of Annual Bluegrass Putting Green Turf 

Influenced by Trinexapac-Ethyl Application Interval and Rate. PHY,POP,REPSOIL,ENV; 

2009; 11, 207-218. 

Rec #: 30

Call Number: NO EFFECT (BFT,CTN,FTL,MZB,TCF,VCZ), NO ENDPOINT 

(BFT,CTN,FTL,MZB,TCF,TXE,VCZ)

Notes: EcoReference No.: 117176

Chemical of Concern: BDC,BFT,BSC,CTN,FTL,MZB,TCF,TXE,VCZ

7. Keever, G. J. and Olive, J. W. Effects of Primo on Selected Bedding and Woody Landscape Plants. 

CEL,GRO,PHY. Dep. Hortic., Ala. Agric. Exp. Stn., Auburn Univ., Auburn, AL 36849//: 

SOIL,ENV; 1998; 16, (1): 11-14. 

Rec #: 220

Call Number: NO ENDPOINT (TXE)

Notes: EcoReference No.: 159852

Chemical of Concern: TXE

8. Klein, J. D.; Mufradi, I.; Cohen, S.; Hebbe, Y.; Asido, S.; Dolgin, B., and Bonfil, D. J. Establishment of 

Wheat Seedlings After Early Sowing and Germination in an Arid Mediterranean Environment. 

GROSOIL,ENV; 2002; 94, (3): 585-593. 

Rec #: 40

Call Number: NO ENDPOINT (TXE), TARGET2012 (PBZ)

Notes: EcoReference No.: 97355

Chemical of Concern: PBZ,TXE

9. Kreuser, W. C. and Soldat, D. J. Frequent Trinexapac-Ethyl Applications Reduce Nitrogen Requirements 

of Creeping Bentgrass Golf Putting Greens. BCM,PHY,POP. American Society of 

Agronomy//: SOIL,ENV,MIXTURE; 2012; 52, (3): 1348-1357. 

Rec #: 100

Call Number: NO CONTROL (CTN,TXE), NO EFFECT (CTN), NO ENDPOINT (TXE)

Notes: EcoReference No.: 159780

Chemical of Concern: CTN,TXE,Urea

10. McCullough, P. E. and Hart, S. E. Creeping Bentgrass (Agrostis stolonifera) Putting Green Tolerance to 

Bispyribac-Sodium. PHY,POP. [McCullough, PE] Univ Georgia, Dept Crop & Soil Sci, 

Griffin, GA 30223 USA [Hart, SE] Rutgers State Univ, Dept Plant Biol & Pathol, New 

Brunswick, NJ 08901 USA//: SOIL,ENV,MIXTURE; 2009; 23, (3): 425-430. 

Rec #: 180

Call Number: NO ENDPOINT (TXE)

Notes: EcoReference No.: 159834

Chemical of Concern: BP,TXE
120

11. ---. Trinexapac-Ethyl Influences Bispyribac-Sodium Absorption and Efficacy for Annual Bluegrass (Poa 

annua) Control in Creeping Bentgrass (Agrostis stolonifera). ACC,PHY,POP. [McCullough, 

PE] Univ Georgia, Dept Crop & Soil Sci, Griffin, GA 30223 USA [Hart, SE] Rutgers State 

Univ, Dept Plant Biol & Pathol, New Brunswick, NJ 08901 USA//: SOIL,ENV,MIXTURE; 

2010; 24, (3): 326-331. 

Rec #: 190

Call Number: NO MIXTURE (TXE)

Notes: EcoReference No.: 159835

Chemical of Concern: BP,TXE

12. McCullough, P. E.; Nutt, W.; Murphy, T. R., and Raymer, P. Seashore Paspalum Seedhead Control and 

Growth Regulation with Flazasulfuron and Trinexapac-Ethyl. 

GRO,PHY,POP,REPSOIL,ENV,MIXTURE; 2011; 25, (1): 64-69. 

Rec #: 200

Call Number: NO ENDPOINT (TXE), OK (FZS)

Notes: EcoReference No.: 159837

Chemical of Concern: FZS,ODZ,TXE

13. Ok, C. H.; Popko, J. T. Jr.; Campbell-Nelson, K., and Jung, G. In Vitro Assessment of Sclerotinia 

homoeocarpa Resistance to Fungicides and Plant Growth Regulators. POPENV; 2011; 95, (1): 

51-56. 

Rec #: 70

Call Number: NO CONTROL 

(FPD,IPD,MCZ,MYC,PBZ,PCZ,PPCP,PPCP2011,TDF,TXE,VCZ), TARGET2012 

(IPD,MCZ,MYC,PCZ,PPCP,PPCP2011,TDF,VCZ)

Notes: EcoReference No.: 159840

Chemical of Concern: 

BSC,FPD,IPD,MCZ,MYC,PBZ,PCZ,PPCP,PPCP2011,TDF,TEZ,TPM,TXE,VCZ

14. Padhye, S. R. and Groninger, J. K. Influence of Benzyladenine, Trinexapac-Ethyl, or Uniconazole 

Applications on Height and Tillering of Six Ornamental Grasses. GROSOIL,ENV; 2009; 19, 

(4): 737-742. 

Rec #: 50

Call Number: NO ENDPOINT (BAD,TXE)

Notes: EcoReference No.: 150932

Chemical of Concern: BAD,TXE

15. Qian, Y. L. and Engelke, M. C. Zoysiagrass in Shade: Influence of Trinexapac-Ethyl. 

BCM,CEL,GRO,PHYSOIL,ENV; 1999; .8, (1): 12-14. 

Rec #: 90

Call Number: NO ENDPOINT (TXE)

Notes: EcoReference No.: 159842

Chemical of Concern: TXE

16. Syhre, M.; Hanschmann, G., and Heber, R. Problems in Analyzing Trinexapac-Ethyl - a New Plant 

Growth Regulator. ACC. Department of Agricultural Analysis (LUFA Leipzig),Agricultural 

Research Centre of Saxonia,Leipzig,Germany//: SOIL,ENV; 1997; 45, (1): 178-179. 

Rec #: 230

Call Number: NO CONTROL (TXE), NO ENDPOINT (TXE)

Notes: EcoReference No.: 159880

Chemical of Concern: TXE

17. Xu, Y. and Huang, B. Responses of Creeping Bentgrass to Trinexapac-Ethyl and Biostimulants Under 

Summer Stress. PHY,POPSOIL,ENV; 2010; 45, (1): 125-131. 

Rec #: 80

Call Number: NO EFFECT (CTN,PCZ,PPCP,PPCP2011,TXE)
121

Notes: EcoReference No.: 159846

Chemical of Concern: CTN,PCZ,PPCP,PPCP2011,TXE

Excluded

1. Abram, Mike. Pgr Can Make More of Water. 2007 Mar 10: 12. 

Rec #: 4490

Keywords: ABSTRACT

Notes: Chemical of Concern: TXE

Abstract: Abstract: The results showed water use in the Moddus plots was less than for 

chlormequat or the untreated control, Mr [Jason Tatnell] says. Effectively, that was because the 

Moddus-shortened plants had less foliar growth and needed less water/nutrients to run the plant, 

he explains. "It makes the plant more efficient."

Keywords: 9175:Western Europe

Keywords: 8640:Chemical industry

Keywords: United Kingdom--UK

Keywords: Agriculture--Crop Production And Soil

Keywords: 5400:Research & development

Copyright - Copyright Reed Business Information UK Mar 10, 2007

Language of summary - English

Location - United Kingdom--UK

Pages - 12

ProQuest ID - 209021572

Document feature - Photographs; Graphs

SubjectsTermNotLitGenreText - United Kingdom--UK

Last updated - 2010-06-08

Place of publication - Sutton

Corporate institution author - Abram, Mike

DOI - 1242095001; 35367891; 52754; CROS; INODCROS0003730534 English

2. Anonymous. Chlormequat Alternatives. 2008 Jun 21: 12. 

Rec #: 4370

Keywords: ABSTRACT

Notes: Chemical of Concern: TXE

Abstract: Abstract: The firm demonstrated some alternative programmes in its demonstration 

area at Cereals, but while initial shortening of wheat crops resulted, alternative products Moddus 

and Canopy, when used without chlormequat, resulted in significant "bounce-back" of the crop, 

he noted.

Keywords: Norman, Keith

Keywords: Agriculture--Crop Production And Soil

Copyright - Copyright Reed Business Information UK Jun 21, 2008

Language of summary - English

Pages - 12

ProQuest ID - 208962493

SubjectsTermNotLitGenreText - Norman, Keith

People - Norman, Keith

Last updated - 2010-06-08

Place of publication - Sutton

Corporate institution author - Anonymous

DOI - 1507708031; 39695221; 52754; CROS; INODCROS0004912261 English

3. Baldwin, C. M.; Liu, H. B.; McCarty, L. B.; Luo, H.; Toler, J., and Long, S. H. Winter foot and 

equipment traffic impacts on a 'L93' creeping bentgrass putting green. 2008; 43, (3): 922-926. 

Rec #: 2450

Keywords: NO TOXICANT

Notes: Chemical of Concern: TXE

Abstract: Abstract: Creeping bentgrass (Agrostis stolonifera var. palustris Huds.) is desirable as 
122

a putting green turfgrass in the transition zone as a result of year-round green color, ball roll, 

and playability. However, management challenges exist for bentgrass greens, including winter 

temperature fluctuations. Frosts often cause cancellations or delays of tee time resulting in lost 

revenue. In response to this winter golf course management issue, a research project was 

initiated at Clemson University from 1 Dec. 2005 and 2006 to 1 Aug. 2006 and 2007 on a 'L93' 

creeping bentgrass putting green to determine the impacts of foot traffic or mower traffic and 

time of traffic application on bentgrass winter performance. Treatments consisted of no traffic 

(control), foot traffic, and walk-behind mower traffic (rolling) at 0700 and 0900 HR when 

canopy temperatures were at or below 0 T. Foot traffic included approximate to 75 steps within 

each plot using size 10 SP-4 Saddle Nike golf shoes (soft-spiked sole) administered by a 

researcher weighing approximate to 75 kg. A Toro Greens-master 800 walk-behind greens 

mower weighing 92 kg with a 45.77-cm roller was used for rolling traffic. Data collected 

included canopy and soil temperatures (7.6 cm depth), visual turfgrass quality (TQ), clipping 

yield (g.m(-2)), shoot chlorophyll concentration (mg.g(-1)) root total nonstructural 

carbohydrates (TNC) (mg.g(-1)), soil bulk density (g.cm(-3)), and water infiltration rates 

(cm.h(-1)). Time and type of traffic significantly influenced bentgrass winter performance. On 

all TQ rating dates, 0700 HR rolling traffic decreased TQ by approximate to 1.1 units compared 

with foot traffic at 0700 HR. In December, regardless of traffic application time, rolling traffic 

reduced bentgrass shoot growth approximate to 17%. However, in February, chlorophyll, soil 

bulk density, and water infiltration differences were not detected. By the end of March, all 

treatments had acceptable TQ. Root TNC was unaffected in May, whereas shoot chlorophyll 

concentrations were unaffected in May and August. This study indicates bentgrass damage 

resulting from winter traffic is limited to winter and early spring months and full recovery 

should be expected by summer.

Keywords: SUBSURFACE AIR MOVEMENT, FREEZING RESISTANCE, PERENNIAL 

RYEGRASS,

ISI Document Delivery No.: 306KC

4. Blake, Andrew . Getting the Best From Invicta. 2010 Jul 24: 22. 

Rec #: 4160

Keywords: ABSTRACT

Notes: Chemical of Concern: TXE

Abstract: Abstract: Provided any temptation to apply N too eany has been avoided, a "cheap and 

cheerful" plant growth regulator programme of chlormequat/ Moddus (trinexapac-ethyl) at 

twothirds rate at the glume primordial stage (GS30) followed by a third at first node (GS31) 

should suffice. Although Invicta's straw length is much the same as [Claire]'s, it is much stiffen 

he notes.

Keywords: 9175:Western Europe

Keywords: 8400:Agriculture industry

Keywords: United Kingdom--UK

Keywords: Agriculture--Crop Production And Soil

Name - Limagrain UK Ltd

Copyright - Copyright Reed Business Information UK Jul 24, 2010

Language of summary - English

Location - United Kingdom--UK

Pages - 22

ProQuest ID - 744088243

Document feature - Photographs; Tables

SubjectsTermNotLitGenreText - United Kingdom--UK

Last updated - 2010-08-16

Place of publication - Sutton

Corporate institution author - Blake, Andrew

DOI - 2111536381; 53900821; 52754; CROS; INODCROS0006682009 English

5. Borger, J. A. Managing Poa annua Seedheads on Putting Greens. SOIL; 2008; 46, (4): 7-8. 

Rec #: 5030
123

Keywords: REFS CHECKED,REVIEW

Call Number: NO REFS CHECKED (EPH,MFD,TXE), NO REVIEW (EPH,MFD,TXE)

Notes: Chemical of Concern: EPH,MFD,TXE

6. Burpee, L. L. Interactions Among Plant Growth Regulators and Fungicides on Dollar Spot of Creeping 

Bentgrass. 1996; 86, (11 suppl.): S104. 

Rec #: 4610

Keywords: ABSTRACT

Notes: Chemical of Concern: TXE

Abstract: ABSTRACT: BIOSIS COPYRIGHT: BIOL ABS. RRM MEETING ABSTRACT 

CREEPING BENTGRASS-CULTIVAR-PENNCROSS FUNGUS HOST PATHOGEN 

PATHOLOGY CROP INDUSTRY PEST MANAGEMENT DOLLAR SPOT 

FLURPRIMIDOL PLANT GROWTH REGULATOR PACLOBUTRAZOL TRINEXAPACETHYL CHLOROTHALONIL FUNGICIDE IPRODIONE PROPICONAZOLE PLANT 

FUNGAL DISEASE

MESH HEADINGS: CONGRESSES

MESH HEADINGS: BIOLOGY

MESH HEADINGS: BIOPHYSICS

MESH HEADINGS: PLANT GROWTH REGULATORS/PHARMACOLOGY

MESH HEADINGS: PLANTS/PHYSIOLOGY

MESH HEADINGS: PLANTS/METABOLISM

MESH HEADINGS: PLANTS/GROWTH & DEVELOPMENT

MESH HEADINGS: PLANTS/DRUG EFFECTS

MESH HEADINGS: PLANTS/GROWTH & DEVELOPMENT

MESH HEADINGS: FUNGI

MESH HEADINGS: PLANT DISEASES

MESH HEADINGS: PLANT DISEASES

MESH HEADINGS: PREVENTIVE MEDICINE

MESH HEADINGS: HERBICIDES

MESH HEADINGS: PEST CONTROL

MESH HEADINGS: PESTICIDES

MESH HEADINGS: FUNGI

MESH HEADINGS: GRASSES

KEYWORDS: General Biology-Symposia

KEYWORDS: Plant Physiology

KEYWORDS: Horticulture-Flowers and Ornamentals

KEYWORDS: Phytopathology-Diseases Caused by Fungi

KEYWORDS: Phytopathology-Disease Control

KEYWORDS: Pest Control

KEYWORDS: Fungi-Unspecified

KEYWORDS: Gramineae eng

7. Chen, Chi-Min; Stowell, Larry; Wong, Frank, and Chen, Chi-Min. The Effects of Nitrogen and 

Trinexapac-Ethyl on the Severity of Brown Ring Patch on Annual Bluegrass Golf Course 

Putting Greens. 2009 Nov 1.

Rec #: 4240

Keywords: ABSTRACT

Notes: Chemical of Concern: TXE

Abstract: Keywords: U 4300:Environmental Science

Conference title - 2009 Annual Meetings of the American Society of Agronomy, Crop Science 

Society of America and Soil Science Society of America (ASA-CSSA-SSSA 2009)

Date revised - 2010-04-06

Language of summary - English

ProQuest ID - 42145735

Last updated - 2010-05-03

Corporate institution author - Chen, Chi-Min; Stowell, Larry; Wong, Frank
124

DOI - CPI-5551197; 5551197 English

8. Cropper, Kenneth; Williams, David; Burrus, Paul, and Cropper, Kenneth. Traffic Tolerance of 

Bermudagrass as Affected by Cultivars and Trinexapac-Ethyl. 2008 Oct 5.

Rec #: 4350

Keywords: ABSTRACT

Notes: Chemical of Concern: TXE

Abstract: Keywords: U 2000:Biological Sciences

Conference title - 2008 Joint Annual Meeting of the Geological Society of America (GSA), Soil 

Science Society of America (SSSA), American Society of Agronomy (ASA), Crop Science 

Society of America (CSSA), and the Gulf Coast Association of Geological Societies with the 

Gulf Coast Section of SEPM (GCAGS)

Date revised - 2009-05-05

Language of summary - English

ProQuest ID - 42070496

Last updated - 2010-05-03

Corporate institution author - Cropper, Kenneth; Williams, David; Burrus, Paul

DOI - CPI-4972581; 4972581 English

9. Deaton, Michael; Williams, David, and Deaton, Michael. Trinexapac-Ethyl and Overseeding Effects on 

Tolerance to Simulated Traffic of Four Bermudagrass Cultivars Grown on a Sand-Based 

System. 2009 Nov 1.

Rec #: 4210

Keywords: ABSTRACT

Notes: Chemical of Concern: TXE

Abstract: Keywords: U 4300:Environmental Science

Conference title - 2009 Annual Meetings of the American Society of Agronomy, Crop Science 

Society of America and Soil Science Society of America (ASA-CSSA-SSSA 2009)

Date revised - 2010-04-06

Language of summary - English

ProQuest ID - 42168829

Last updated - 2010-05-03

Corporate institution author - Deaton, Michael; Williams, David

DOI - CPI-5553460; 5553460 English

10. Dillon, K; Walker, T; Tarpley, L; Bond, J, and Dillon, K. Trinexapac-Ethyl as a Potential Tool to 

Improve Harvestable Yield Potential for Hybrid Rice. 2010 Feb 22.

Rec #: 4180

Keywords: ABSTRACT

Notes: Chemical of Concern: TXE

Abstract: Keywords: U 7000:Multidisciplinary

Conference title - 33rd Rice Technical Working Group Meeting (RTWG 2010)

Date revised - 2010-04-06

Language of summary - English

ProQuest ID - 42365985

Last updated - 2010-05-03

Corporate institution author - Dillon, K; Walker, T; Tarpley, L; Bond, J

DOI - CPI-5667627; 5667627 English

11. Dillon, Kevin; Walker, Timothy; Koger, Clifford; Varco, Jac, and Dillon, Kevin. Evaluation of 

Trinexapac-Ethyl to Reduce Lodging for Hybrid Rice. 2010 Feb 7.

Rec #: 4190

Keywords: ABSTRACT

Notes: Chemical of Concern: TXE

Abstract: Keywords: U 4300:Environmental Science

Conference title - 2010 Annual Meeting of the Southern Regional Branch of the American 
125

Society for Agronomy

Date revised - 2010-04-06

Language of summary - English

ProQuest ID - 42357956

Last updated - 2010-05-03

Corporate institution author - Dillon, Kevin; Walker, Timothy; Koger, Clifford; Varco, Jac

DOI - CPI-5658001; 5658001 English

12. Fagerness, M. J. and Yelverton, F. H. Regulation of 'Tifway' bermudagrass growth and development with 

trinexapac-ethyl and paclobutrazol. 1999. v. 52, 68-69. 

Rec #: 3280

Keywords: ABSTRACT

Notes: Chemical of Concern: TXE

Abstract: Paper presented at the "A Glance to the Past, A Vision for the Future" 52nd Annual 

Meeting, January 25-27, 1999, Greensboro, North Carolina.

13. Fidanza, M. A.; Wetzel III, H. C.; Agnew, M. L., and Kaminski, J. E. Evaluation of Fungicide and Plant 

Growth Regulator Tank-Mix Programmes on Dollar Spot Severity of Creeping Bentgrass. 2006; 

25, (9): 1032-1038. 

Rec #: 5080

Keywords: MIXTURE

Call Number: NO MIXTURE (AZX,CTN,PBZ,PCZ,PPCP,PPCP2011,TXE)

Notes: Chemical of Concern: AZX,CTN,FDX,PBZ,PCZ,PPCP,PPCP2011,TXE

14. Gardner, David; Nangle, Edward; Street, John; Danneberger, Karl T; Metzger, James, and Gardner, 

David. The Effect of Trinexapac Ethyl and Three Nitrogen Sources on Creeping Bentgrass 

Agrostis Stolonifera L. Grown Under Three Light Environments. 2008 Oct 5.

Rec #: 4340

Keywords: ABSTRACT

Notes: Chemical of Concern: TXE

Abstract: Keywords: U 2000:Biological Sciences

Conference title - 2008 Joint Annual Meeting of the Geological Society of America (GSA), Soil 

Science Society of America (SSSA), American Society of Agronomy (ASA), Crop Science 

Society of America (CSSA), and the Gulf Coast Association of Geological Societies with the 

Gulf Coast Section of SEPM (GCAGS)

Date revised - 2009-05-05

Language of summary - English

ProQuest ID - 42061697

Last updated - 2010-05-03

Corporate institution author - Gardner, David; Nangle, Edward; Street, John; Danneberger, Karl 

T; Metzger, James

DOI - CPI-4972594; 4972594 English

15. Haselbauer, William; Sorochan, John; Brosnan, James; Samples, Thomas, and Haselbauer, William. 

Effects of Trinexapac-Ethyl on the Traffic Tolerance of Four Bermudagrass Cultivars. 2009 

Nov 1.

Rec #: 4260

Keywords: ABSTRACT

Notes: Chemical of Concern: TXE

Abstract: Keywords: U 4300:Environmental Science

Conference title - 2009 Annual Meetings of the American Society of Agronomy, Crop Science 

Society of America and Soil Science Society of America (ASA-CSSA-SSSA 2009)

Date revised - 2010-04-06

Language of summary - English

ProQuest ID - 42144266

Last updated - 2010-05-03
126

Corporate institution author - Haselbauer, William; Sorochan, John; Brosnan, James; Samples, 

Thomas

DOI - CPI-5551209; 5551209 English

16. Heckman, N. L.; Horst, G. L.; Gaussoin, R. E., and Frank, K. W. Storage and Handling Characteristics of 

Trinexapac-Ethyl Treated Kentucky Bluegrass Sod. N.L. Heckman, Department of Agronomy, 

University of Nebraska-Lincoln, Lincoln, NE 68583-0724//: 2001; 36, (6): 1127-1130. 

Rec #: 5020

Keywords: BENEFICIAL EFFECT

Call Number: NO BENEFICIAL EFFECT (TXE)

Notes: Chemical of Concern: TXE

17. Impey, Louise. Variable Application Trials Surprising. 2009 Mar 28: 10. 

Rec #: 4280

Keywords: ABSTRACT

Notes: Chemical of Concern: TXE

Abstract: Abstract: "It's important to bear in mind this was just one trial," he says. But it could 

be explained by Moddus' ability to promote tillering and root growth in struggling crops, he 

suggests. "That's very relevant to this season. There are a number of backwards crops out there, 

which can be given a kick-start with the right dose of PGR For the majority, the helping-hand 

approach is needed."

Keywords: 9175:Western Europe

Keywords: 8400:Agriculture industry

Keywords: United Kingdom--UK

Keywords: Agriculture--Crop Production And Soil

Copyright - Copyright Reed Business Information UK Mar 28, 2009

Language of summary - English

Location - United Kingdom--UK

Pages - 10

ProQuest ID - 208960619

Document feature - Photographs

SubjectsTermNotLitGenreText - United Kingdom--UK

Last updated - 2010-06-08

Place of publication - Sutton

Corporate institution author - Impey, Louise

DOI - 1681821831; 42579661; 52754; CROS; INODCROS0005618258 English

18. Inguagiato, J. C. Anthracnose Severity Influenced by Cultural Management of Annual Bluegrass Putting 

Green Turf. 2009: 253 p. (UMI# 3350124). 

Rec #: 4990

Keywords: PUBL AS

Call Number: NO PUBL AS (EPH,MFD,TXE)

Notes: Chemical of Concern: EPH,MFD,TXE

19. Klein, Joshua and Klein, Joshua. Trinexapac-Ethyl Promotes Drought Resistance by Changing 

Epicuticular Wax Synthesis, Structure and Composition. 2010 Jun 28.

Rec #: 4170

Keywords: ABSTRACT

Notes: Chemical of Concern: TXE

Abstract: Keywords: U 7000:Multidisciplinary

Conference title - 20th International Conference on Plant Growth Substances (IPGSA 2010)

Date revised - 2011-01-11

Language of summary - English

ProQuest ID - 839708548

Last updated - 2011-01-14

Corporate institution author - Klein, Joshua
127

DOI - CPI-5948546; 5948546 English

20. Kreuser, W; Soldat, D, and Kreuser, W. Use of a Growing Degree Model to Schedule Trinexapac- Ethyl 

Applications to Creeping Bentgrass Golf Putting Greens. 2009 Nov 1.

Rec #: 4250

Keywords: ABSTRACT

Notes: Chemical of Concern: TXE

Abstract: Keywords: U 4300:Environmental Science

Conference title - 2009 Annual Meetings of the American Society of Agronomy, Crop Science 

Society of America and Soil Science Society of America (ASA-CSSA-SSSA 2009)

Date revised - 2010-04-06

Language of summary - English

ProQuest ID - 42138537

Last updated - 2010-05-03

Corporate institution author - Kreuser, W; Soldat, D

DOI - CPI-5551975; 5551975 English

21. Li, Qiang and Li, Xue Feng. Substitution of Highly-Toxic Pesticides Screening and Mixture on Bradysia 

Odoriphaga. 2007.

Rec #: 4880

Keywords: NON-ENGLISH

Notes: Chemical of Concern: TXE

Abstract: Abstract: Bradysia odoriphaga Yang et Zhang, whose larva is called Bradysia spp, 

causes great damage to china chives, garlic, spring onion, green Chinese onion and etc. The 

highly-toxic pesticides were used to control it and made a potential threat on security of china 

chives. The objectives of this paper is to determine the toxicity of substitute chemicals with 

different mechanism and screen the substitutions, providing data for the further field tests. 

Meanwhile, methods of toxicity and standard of death were discussed primarily. The study of 

mixtures of several pesticides was also carried out. Single concentration toxicity to 3-instar 

larvae was measured using lambda-cyhalothrin and beta-cypermethrin with two chosen 

concentrations.The percentage change of judgement of two standards of death which were the 

insects could not naturally creep and immobility of body, it indicated that the influence of the 

two methods on LC50 from formulation to insects was significant. Variation of LC50 

measured by four methods was much. The general trends in ranking of LC50 measured was 

almost same. The result indicated the ranking was contact&stomach method<filter paper< 

dipping leaf or dipping insects. Toxicity of 16 pesticides was measured on the 3-instar larva 

using the contact&stomach method.The result showed that chlorpyrifos showed higher toxicity 

to the insects with LD50 up to 0.384mg/L. Toxicity of 16 pesticides to the larva of Bradysia 

odoriphaga was declining in the order as following: Chlorpyrifos, imidacloprid, phoxim, 

lambda-cyhalothrin, acetamiprid, beta-cypermethrin, carbaryl, malathion, ethoprophos, 

diazinon, endosulfan, cyfluthrin, carbosulfan, chloramine phosphorus, xiaochongliulin. 

Cyromazine belonged to insect growth regulator had no significant effect on the insect within 72 

hours. The result demonstrated that the mixtures of chlorpyrifos and lambda-cyhalothrin had 

the most synergistic effect, the CTC, at the ration of 1:5,was 356. The mixture of chlorpyrifos 

and acetamiprid had insignificant synergistic effect, the CTC, at the ration of 1:9 and 1:19, were 

180 and 173.

Keywords: 0285:Agronomy

Keywords: Biological sciences

Keywords: (UMI)AAIH219836

0285: Agronomy

2712565341

2007

Chinese

1026555212

Copyright ProQuest, UMI Dissertations Publishing 2007

n/a
128

(UMI)AAIH219836

Li, Qiang

169031

Biological sciences

H219836

2012-07-17

70523942 ZH

22. Lopez-Bellido, R. J.; Lal, R.; Danneberger, T. K., and Street, J. R. Plant Growth Regulator and Nitrogen 

Fertilizer Effects on Soil Organic Carbon Sequestration in Creeping Bentgrass Fairway Turf. 

[Lopez-Bellido, RJ] Univ Cordoba, Dept Ciencias & Recursos Agr & Forestales, Cordoba 

14071, Spain [Lal, R] Ohio State Univ, Carbon Management & Sequestrat Ctr, Columbus, OH 

43210 USA//: SOIL; 2010; 332, (1/2): 247-255. 

Rec #: 5000

Keywords: FATE

Call Number: NO FATE (LQN,PBZ,TXE)

Notes: Chemical of Concern: LQN,PBZ,TXE

23. McCann, S. E. Water Use and Summer Stress Tolerance Mechanisms for Creeping Bentgrass and 

Kentucky Bluegrass. 2008: 207 p. (UMI# 3349586 ). 

Rec #: 4860

Keywords: BENEFICIAL EFFECT

Notes: Chemical of Concern: TXE

Abstract: Abstract: Creeping bentgrass (Agrostis stoloniferia ) and Kentucky bluegrass (Poa 

Pratensis L.) are two widely-used cool-season grasses grown extensively in northern regions of 

the United States. Creeping bentgrass is primarily used on golf courses, while Kentucky 

bluegrass has extensive uses in both home lawns and sports fields. Each of these areas of use are 

coming under increased scrutiny in regards to water management and conservation. 

Communities are increasingly putting greater restrictions on both the amount and type of water 

that can be used for irrigating golf courses, sports fields, and home lawns. The focus of our 

project was to develop a greater understanding of these grasses' water use, as a way to establish 

ideal water management practices. The field portion of the project focused on irrigation 

frequency as applied to three bentgrass species maintained as golf course fairways. Results 

suggested that reducing frequency and watering one or two times per week, while still replacing 

100% of evapotranspiration (ET), produced equivalent, if not improved turf quality, and actually 

held water deeper in the soil profile, reducing evaporation losses to the atmosphere. In addition 

to the field portion of the project, experiments were conducted in growth chambers evaluating 

both creeping bentgrass and Kentucky bluegrass physiological responses to drought and summer 

stress. Specific findings suggested that exfoliar application of abscisic acid (ABA) or 

trinexapac-ethyl, a giberrelin inhibitor, significantly improved plant drought tolerance. 

Further research evaluated genotypic variation between varieties of these species, suggesting 

that both tolerance and avoidance traits are employed to protect plant physiological function 

under water deficit.

Start Page: 207

ISSN/ISBN: 9781109055887

Keywords: 0309:Plant biology

Keywords: Water use

Keywords: Kentucky bluegrass

Keywords: 0817:Plant biology

Keywords: Stress tolerance

Keywords: 0471:Horticulture

Keywords: Biological sciences

Keywords: Creeping bentgrass

2008

0471: Horticulture

Kentucky bluegrass
129

1683354491

3349586

41273611

2012-07-19

Stress tolerance

0817: Plant biology

66569

9781109055887

n/a

Copyright ProQuest, UMI Dissertations Publishing 2008

English

Water use

304511722

McCann, Stephen E.

Biological sciences

0309: Plant biology

Creeping bentgrass English

24. McCann, S. E. Water Use and Summer Stress Tolerance Mechanisms for Creeping Bentgrass and 

Kentucky Bluegrass. SOIL; 2008: 207 p. (UMI# 3349586). 

Rec #: 5050

Keywords: BENEFICIAL EFFECT

Notes: Chemical of Concern: TXE

25. Mccullough, P; Hart, S, and McCullough, P. Trinexapac-Ethyl Influences Efficacy and Foliar Absorption 

of Bispyribac-Sodium. 2007 Jan 2.

Rec #: 4540

Keywords: ABSTRACT

Notes: Chemical of Concern: TXE

Abstract: Keywords: U 2000:Biological Sciences

Conference title - 61st Annual Meeting of the Northeastern Weed Science Society

Date revised - 2007-09-05

Language of summary - English

ProQuest ID - 39401911

Last updated - 2010-05-03

Corporate institution author - McCullough, P; Hart, S

DOI - CPI-4509771; 4509771 English

26. Moss, Justin; Su, Kemin; Poudel, Bishow, and Moss, Justin. Evaluation of Combinations of BispyribacSodium or Amicarbazone With Trinexapac-Ethyl or Paclobutrazol for Annual Bluegrass 

Control on Creeping Bentgrass Greens. 2009 Nov 1.

Rec #: 4220

Keywords: ABSTRACT

Notes: Chemical of Concern: TXE

Abstract: Keywords: U 4300:Environmental Science

Conference title - 2009 Annual Meetings of the American Society of Agronomy, Crop Science 

Society of America and Soil Science Society of America (ASA-CSSA-SSSA 2009)

Date revised - 2010-04-06

Language of summary - English

ProQuest ID - 42137150

Last updated - 2010-05-03

Corporate institution author - Moss, Justin; Su, Kemin; Poudel, Bishow

DOI - CPI-5552012; 5552012 English

27. Nolte, Kurt and Nolte, Kurt. The Pgr, Trinexapac-Ethyl Reduces Lodging in Desert Durum Wheat. 2007 

Jul 16.
130

Rec #: 4480

Keywords: ABSTRACT

Notes: Chemical of Concern: TXE

Abstract: Keywords: U 7000:Multidisciplinary

Conference title - 2007 Annual Conference of the American Society for Horticultural Science 

(ASHS 2007)

Date revised - 2007-12-18

Language of summary - English

ProQuest ID - 39404329

Last updated - 2010-05-03

Corporate institution author - Nolte, Kurt

DOI - CPI-4613491; 4613491 English

28. Porpiglia, P.; Towne, O., and Houseworth, D. Overview of the Turf Weed Control Market in the Usa. 

1996; 47, (4): 387-388. 

Rec #: 4960

Keywords: ABSTRACT

Notes: Chemical of Concern: TXE

Abstract: ABSTRACT: BIOSIS COPYRIGHT: BIOL ABS. RRM MEETING PAPER 

LOLIUM-SPP FESTUCA-SPP AGROSTIS-STOLINIFERA POA-PRATENSIS POA-ANNUA 

CYNODON-SPP EREMOCHLOA-OPHIUROIDES STENOTAPHRUM-SECUNDATUM 

PENNISETUM-CLANDESTINUM KIKUYUGRASS ZOYSIA-SPP GRASS WEEDS 

KENTUCKY BLUEGRASS ANNUAL BLUEGRASS CENTIPEDEGRASS ST 

AUGUSTINEGRASS ZOYSIAGRASS PERENNIAL RYEGRASSES ANNUAL 

RYEGRASSES RED FESCUE CREEPING DWARF FESCUE TALL FESCUE SEMIDWARF FESCUE TURF PLANT WEED HORTICULTURE BIOBUSINESS TURF WEED 

CONTROL MARKET MAINTENANCE LEVEL PESTICIDES APPLICATION RATE 

PESTICIDE TURF CLIMATES PLANT GROWTH REGULATOR SELECTIVITY 

HERBICIDE COST SAFETY PEST MANAGEMENT TRINEXAPAC-ETHYL CIBA 

PACLOBUTRAZOL FLURPRIMIDOL USA NORTH AMERICA

MESH HEADINGS: CLIMATE

MESH HEADINGS: ECOLOGY

MESH HEADINGS: METEOROLOGICAL FACTORS

MESH HEADINGS: ECOLOGY

MESH HEADINGS: PLANTS

MESH HEADINGS: BIOCHEMISTRY

MESH HEADINGS: GRASSES/GROWTH & DEVELOPMENT

MESH HEADINGS: SOIL

MESH HEADINGS: PLANTS/GROWTH & DEVELOPMENT

MESH HEADINGS: HERBICIDES

MESH HEADINGS: PEST CONTROL

MESH HEADINGS: PESTICIDES

MESH HEADINGS: PLANTS

MESH HEADINGS: GRASSES

KEYWORDS: Ecology

KEYWORDS: Ecology

KEYWORDS: Biochemical Studies-General

KEYWORDS: Agronomy-Weed Control

KEYWORDS: Horticulture-Flowers and Ornamentals

KEYWORDS: Pest Control

KEYWORDS: Tracheophyta

KEYWORDS: Gramineae eng

29. Raeppel, C.; Nief, M.; Fabritius, M.; Racault, L.; Appenzeller, B. M., and Millet, M. Simultaneous 

Analysis of Pesticides From Different Chemical Classes by Using a Derivatisation Step and Gas 

Chromatography-Mass Spectrometry. 
131

Rec #: 4980

Keywords: CHEM METHODS

Notes: Chemical of Concern: TXE

Abstract: ABSTRACT: This work presents a new method to analyse simultaneously by GC-MS 

31 pesticides from different chemical classes (2,4 D, 2,4 MCPA, alphacypermethrin, bifenthrin, 

bromoxynil, buprofezin, carbaryl, carbofuran, clopyralid, cyprodinil, deltamethrin dicamba, 

dichlobenil, dichlorprop, diflufenican, diuron, fenoxaprop, flazasulfuron, fluroxypyr, ioxynil, 

isoxaben, mecoprop-P, myclobutanil, oryzalin, oxadiazon, picloram, tau-fluvalinate 

tebuconazole, triclopyr, trifluralin and trinexapac-p-ethyl). This GC-MS method will be applied 

to the analysis of passive samplers (Tenax(®) tubes and SPME fiber) used for the evaluation 

of the indoor and outdoor atmospheric contamination by non-agricultural pesticides. The 

method involves a derivatisation step for thermo-labile or polar pesticides. Different agents were 

tested and MtBSTFA (N-(t-butyldimethylsilyl)-N-methyltrifluoroacetamide), a sylilation agent 

producing very specific fragments [M-57], was retained. However, diuron could not be 

derivatised and the isocyanate product was used for identification and quantification. Pesticides 

which did not need a derivatisation step were not affected by the presence of the derivatisation 

agent and they could easily be analysed in mixture with derivatised pesticides. The method can 

be coupled to a thermal-desorption unit or to SPME extraction for a multiresidue analysis of 

various pesticides in atmospheric samples.

MESH HEADINGS: Acetamides

MESH HEADINGS: Acylation

MESH HEADINGS: Amides/chemistry

MESH HEADINGS: Fluoroacetates

MESH HEADINGS: Gas Chromatography-Mass Spectrometry/*methods

MESH HEADINGS: Organosilicon Compounds/chemistry

MESH HEADINGS: Pesticides/*analysis/chemistry/classification

MESH HEADINGS: Sensitivity and Specificity

MESH HEADINGS: Trifluoroacetic Acid/chemistry

MESH HEADINGS: Trimethylsilyl Compounds/chemistry eng

30. Rajala, A. and Peltonen-Sainio, P. Plant Growth Regulator Effects on Spring Cereal Root and Shoot 

Growth. SOIL; 2001; 93, (4): 936-943. 

Rec #: 5010

Keywords: NO CONC

Call Number: NO CONC (CQTC,EPH,TXE)

Notes: Chemical of Concern: CQTC,EPH,TXE

31. Ramoutar, D. Pyrethroid Resistance in the Annual Bluegrass Weevil, Listronotus maculicollis 

(Coleoptera: Curculionidae), from Southern New England Golf Courses. 2009: 161 p. (UMI# 

3415505)(Publ As 155217, 156577, 152401). 

Rec #: 5070

Keywords: PUBL AS

Call Number: NO PUBL AS 

(BFT,FPD,FRM,LCYT,PBZ,PCZ,PPB,PPCP,PPCP2011,TBF,TXE)

Notes: Chemical of Concern: 

BFT,CTD,FPD,FRM,LCYT,PBZ,PCZ,PPB,PPCP,PPCP2011,SS,TBF,TXE

32. Sladek, B. S.; Henry, G. M., and Auld, D. L. Evaluation of Zoysiagrass Genotypes for Shade Tolerance. 

2009; 44, (5): 1447-1451. 

Rec #: 2860

Keywords: NO TOXICANT

Notes: Chemical of Concern: TXE

Abstract: Abstract: Establishing turfgrass in shaded environments can create a unique 

maintenance challenge. Shading reduces zoysiagrass (Zoysia spp.) photosynthesis and results in 

reduced turfgrass aesthetic quality. Zoysiagrass is a warm-season, perennial turfgrass that forms 

a dense, uniform turf through the production of rhizomes and stolons. It has demonstrated good 
132

tolerance to growth in reduced light intensity environments. Greenhouse experiments were 

conducted in 2006 and 2007 to evaluate the relative difference in growth response to three light 

intensities (0%, 50%, and 90% shade) among six zoysiagrass genotypes under artificial shade 

conditions. Percent change in zoysiagrass plug diameter decreased as shade level increased 6 

and 12 weeks after planting (WAP) regardless of year or genotype. 'Diamond' and 'Shadow Turf' 

exhibited the greatest percent change in plug diameter 12 WAP (60% to 69%) followed by the 

remaining zoysiagrass genotypes (21% to 56%) when grown under 50% shade, regardless of 

year. In 2006, no zoysiagrass genotype maintained acceptable turfgrass quality (6 or greater) 12 

WAP when grown under 54% shade. However, 'Diamond' and 'Shadow Turf' exhibited 

acceptable turfgrass quality ratings (7.0 and 6.3) 12 WAP in 2007, whereas all other genotypes 

exhibited unacceptable turfgrass quality ratings (5.0 to 5.7). In 2006, 'Shadow Turf' zoysiagrass 

exhibited the greatest percent increase in plug diameter (21%) followed by 'DALZ 0501' (15%) 

and 'Diamond' (5%) 12 WAP when grown under 90% shade. All other zoysiagrass genotypes 

exhibited decreases in plug diameter (31% to 87%). In 2 007, 'Shadow Turf and 'Diamond' 

exhibited the greatest percent change in plug diameter (11%) followed by 'DALZ 0501' (7%) 12 

WAP when grown under 90% shade. All other zoysiagrass genotypes exhibited decreases in 

plug diameter (17% to 38%). Turfgrass quality declined as shade level increased 6 and 12 WAP 

regardless of year or genotype. 'Shadow Turf' and 'Diamond' exhibited the highest turfgrass 

quality ratings (4.7 and 3.7, respectively, in 2006 and 5.3 in 2007) 12 WAP when grown under 

90% shade. Proper zoysiagrass cultivar selection may improve turfgrass growth and quality 

under low light intensity while increasing turfgrass options for shaded environments.

Keywords: Zoysia japonica, Zoysia matrella, light intensity

ISI Document Delivery No.: 487KS

33. Spinelli, F. ; Vanneste, J. L., and Costa, G. Acylcyclohexanediones and biological control agents: 

combining complementary modes of action to control fire blight. 2012; 26, (1): 247-257. 

Rec #: 2890

Keywords: BENEFICIAL EFFECT

Notes: Chemical of Concern: TXE

Abstract: Abstract: Acylcyclohexanediones and antagonistic bacteria sprayed alone or in 

combination have been shown to suppress fire blight of apple and pear. 

Acylcyclohexanediones, such as prohexadione- calcium and trinexapacethyl, increase plant 

resistance and are effective against the shoot blight phase of the disease. Antagonistic bacteria, 

such as Pantoea agglomerans, compete with the pathogen (Erwinia amylovora) for space and 

nutrients on stigmas, which prevents blossom blight. Potential synergistic effects of 

acylcyclohexanediones with P. agglomerans for fire blight suppression were investigated on 

leaves and flowers of apple and pear. Acylcyclohexanediones modified the composition of apple 

nectar and stigmatic secretions, which resulted in moderately higher epiphytic populations of P. 

agglomerans strain P10c. In experiments in apple orchards, the combination of 

acylcyclohexanediones and P. agglomerans gave the greatest protection against blossom blight 

and shoot blight. In pear orchards, under natural infection conditions, a similar result was 

obtained for the 3 of the 4 years of the experiment.

Keywords: Pantoea agglomerans, Prohexadionecalcium, Trinexapac-ethyl, Malus

ISI Document Delivery No.: 912FB

34. Steinke, K. and Stier, J. C. Nitrogen Selection and Growth Regulator Applications for Improving Shaded 

Turf Performance. jstier@facstaff.wisc.edu//J.C. Stier, Dep. of Horticulture, Univ. of 

Wisconsin, Madison, WI 53706////: SOIL; 2003; 43, (4): 1399-1406. 

Rec #: 5040

Keywords: BENEFICIAL EFFECT

Call Number: NO BENEFICIAL EFFECT (TXE)

Notes: Chemical of Concern: TXE,Urea

35. Stiglbauer, J. B. Establishment and Management Practices of Two New Warm-Season Turfgrasses in the 

Southern Transition Zone. SOIL; 2010: 107 p. (UMI# 1475581). 

Rec #: 5060
133

Keywords: BENEFICIAL EFFECT

Notes: Chemical of Concern: TXE

36. Studzinska, A. K.; Gardner, D. S.; Metzger, J. D.; Shetlar, D.; Harriman, R., and Danneberger, T. K. The 

Effect of PcGA2ox Overexpression on Creeping Bentgrass (Agrostis stolonifera L.): 

Performance under Various Light Environments. 2012; 47, (2): 280-284. 

Rec #: 2910

Keywords: NO TOXICANT

Notes: Chemical of Concern: TXE

Abstract: Abstract: Turf grown in shade exhibits increased stem elongation. Dwarfism could 

improve turfgrass quality by reducing elongation. The purpose of this study was to examine the 

effect of GA2-oxidase (GA2ox) overexpression on creeping bentgrass (Agrostis stolonifera L.) 

performance under restricted light conditions and low mowing heights. Greenhouse studies were 

conducted at The Ohio State University, Columbus, OH, from 1 Sept. to 31 Oct. in both 2008 

and 2009. Two experimental lines, Ax6548 and Ax6549, transformed with CP4 EPSPS and 

PcGA2ox gene; and a nontransformed control (NTC) was subjected to four light environments: 

full sun, reduced red to far red light ratio (R:FR), neutral shade [reduced photosynthetic photon 

flux (PPF)], and canopy shade (reduced PPF and R:FR). Turf was evaluated every 10 days for 

color and percent coverage. GA2ox overexpression resulted in darker green color in both 

transgenic lines under all light treatments as compared with NTC plants. No differences in 

overall turfgrass coverage were noted in full sun conditions among the lines. A significant 

decrease in turf coverage occurred for all shade treatments regardless of line. However, Ax6549 

decreased the least. Overall data indicated that GA2ox overexpression can improve quality of 

turfgrass under reduced light conditions.

Keywords: TRINEXAPAC-ETHYL, GIBBERELLIN BIOSYNTHESIS, KENTUCKY 

BLUEGRASS, TALL

ISI Document Delivery No.: 900VP

37. Thoms, Adam; Sorochan, John; Brosnan, James; Breeden, Greg; Samples, Thomas, and Thoms, Adam. 

Effects of Grooming and Trinexapac-Ethyl Applications on Zoysiagrass Fairways in the 

Transition Zone. 2009 Nov 1.

Rec #: 4230

Keywords: ABSTRACT

Notes: Chemical of Concern: TXE

Abstract: Keywords: U 4300:Environmental Science

Conference title - 2009 Annual Meetings of the American Society of Agronomy, Crop Science 

Society of America and Soil Science Society of America (ASA-CSSA-SSSA 2009)

Date revised - 2010-04-06

Language of summary - English

ProQuest ID - 42137571

Last updated - 2010-05-03

Corporate institution author - Thoms, Adam; Sorochan, John; Brosnan, James; Breeden, Greg; 

Samples, Thomas

DOI - CPI-5551985; 5551985 English

38. Villa-Ruano, N.; Betancourt-Jimenez, M. G., and Lozoya-Gloria, E. Biosynthesis of Uterotonic 

Diterpenes From Montanoa Tomentosa (Zoapatle). 2009 Dec 15; 166, (18): 1961-7. 

Rec #: 4680

Keywords: HUMAN HEALTH

Notes: Chemical of Concern: TXE

Abstract: ABSTRACT: Montanoa tomentosa (zoapatle) is a Central American plant used in 

Mexico in traditional herbal medicine to ease childbirth labor and to cure certain female 

disorders. Recently, crude extracts of M. tomentosa have been reported to have an 

aphrodisiacal effect on male rats. The bioactive molecules are the uterotonic diterpenes 

kaurenoic acid (KA), grandiflorenic acid (GF), and monoginoic acid (MO). Roots of M. 

tomentosa contain all three diterpenes, whereas in leaves only kaurenoic and GF are present. 
134

However, despite the pharmacological importance of these compounds, specific information 

about their biosynthesis and localization in the plant is not available. In this investigation, we 

followed the metabolic transformation of a tritium-labeled diterpene-precursor via 

geranylgeranyl diphosphate into each of the three diterpenes. Inhibitors of gibberellin 

biosynthesis were used to elucidate the sequence of conversion of the intermediates. Our results 

suggest the biosynthetic conversion of KA into GF by a putative cytochrome P450-like 

desaturase. Partial characterization of the enzyme revealed that it requires NADPH and O2 but 

is inhibited by 50 microM paclobutrazol, suggesting a cytochrome P450 desaturase like enzyme 

(EC 1.14.14.-). Optimal reaction conditions are 32 degrees C and a pH of 7.6, respectively. 

Apparent kinetics parameters for KA gave a K(m,app) of 36.31 microM, and a V(max, app) of 

13.6 nmol KA mg(1)protein h(-1). Based on the data presented, a putative biosynthetic pathway 

is proposed for the uterotonic diterpenes of M. tomentosa.

MESH HEADINGS: Chlormequat

MESH HEADINGS: Cyclopropanes

MESH HEADINGS: Diterpenes/*metabolism

MESH HEADINGS: Gibberellins/antagonists & inhibitors

MESH HEADINGS: Microsomes/metabolism

MESH HEADINGS: Montanoa/*metabolism

MESH HEADINGS: Oxidoreductases Acting on CH-CH Group Donors/metabolism

MESH HEADINGS: Plant Growth Regulators

MESH HEADINGS: Plant Leaves/metabolism

MESH HEADINGS: Plant Proteins/metabolism

MESH HEADINGS: Plant Roots/metabolism

MESH HEADINGS: Plants, Medicinal/metabolism

MESH HEADINGS: Polyisoprenyl Phosphates/metabolism

MESH HEADINGS: Quinones

MESH HEADINGS: Triazoles

MESH HEADINGS: Tritium eng

39. Yelverton, F. H. Effects of trinexapac-ethyl and paclobutrazol on ball roll and summer stress of creeping 

bentgrass. 1998. v. 51, 68. 

Rec #: 3960

Keywords: ABSTRACT

Notes: Chemical of Concern: TXE

Abstract: Paper presented at the "Preparing for the New Millenium" 51st Annual Meeting, 

January 26-28, 1998, Birmingham, Alabama.
135

Appendix E – SIP and STIR Model Output

STIR

The most sensitive bird data was from the zebra finch. 

Input

Application and Chemical Information

Enter Chemical Name Trinexapac-ethyl

Enter Chemical Use Growth regulator

Is the Application a Spray? (enter y or n) y

If Spray What Type (enter ground or air) air

Enter Chemical Molecular Weight (g/mole) 252.3

Enter Chemical Vapor Pressure (mmHg) 1.62E-05

Enter Application Rate (lb a.i./acre) 1.36

Toxicity Properties

Bird

Enter Lowest Bird Oral LD50 (mg/kg bw) 813

Enter Mineau Scaling Factor 1.15

Enter Tested Bird Weight (kg) 0.0115

Mammal

Enter Lowest Rat Oral LD50 (mg/kg bw) 4212

Enter Lowest Rat Inhalation LC50 (mg/L) 2.51

Duration of Rat Inhalation Study (hrs) 4

Enter Rat Weight (kg) 0.35

Output

Results Avian (0.020 kg )

Maximum Vapor Concentration in Air at Saturation 

(mg/m3) 2.20E-01

Maximum 1-hour Vapor Inhalation Dose (mg/kg) 2.76E-02

Adjusted Inhalation LD50 4.07E+00

Ratio of Vapor Dose to Adjusted Inhalation LD50 6.79E-03 Exposure not Likely Significant

Maximum Post-treatment Spray Inhalation Dose (mg/kg) 1.31E-01

Ratio of Droplet Inhalation Dose to Adjusted Inhalation 

LD50 3.21E-02 Exposure not Likely Significant

Results Mammalian (0.015 kg )

Maximum Vapor Concentration in Air at Saturation 

(mg/m3) 2.20E-01

Maximum 1-hour Vapor Inhalation Dose (mg/kg) 3.48E-02

Adjusted Inhalation LD50 1.49E+02
136

Ratio of Vapor Dose to Adjusted Inhalation LD50 2.33E-04 Exposure not Likely Significant

Maximum Post-treatment Spray Inhalation Dose (mg/kg) 1.64E-01

Ratio of Droplet Inhalation Dose to Adjusted Inhalation 

LD50 1.10E-03 Exposure not Likely Significant

SIP

Two items should be noted in the inputs. First, the solubility value is reported for a pH of 

5.5. A solubility value was also reported at a pH of 8.2 (21100). Using the higher value does 

not change the overall conclusion of the model. Secondly, the zebra finch provided the most 

sensitive LD50, when compared with the mallard duck and bobwhite quail. The body weight 

was taken from the DER (MRID 48894501) and the lowest number in the body weigh range 

was used (11.5 to 15.8 g). Using the higher body weight does not change the overall 

conclusion of the model.

Table 1. Inputs

Parameter Value

Chemical name Trinexapac-ethyl

Solubility (in water at 25oC; mg/L) 10200

Mammalian LD50 (mg/kg-bw) 4212

Mammalian test species laboratory rat

Body weight (g) of "other" mammalian 

species

Mammalian NOAEL (mg/kg-bw) 594

Mammalian test species laboratory rat

Body weight (g) of "other" mammalian 

species

Avian LD50 (mg/kg-bw) 813

Avian test species other

Body weight (g) of "other" avian species 11.5

Mineau scaling factor 1.15

Mallard NOAEC (mg/kg-diet) 600

Bobwhite quail NOAEC (mg/kg-diet) 200

NOAEC (mg/kg-diet) for other bird species

Body weight (g) of other avian species

NOAEC (mg/kg-diet) for 2nd other bird 

species

Body weight (g) of 2nd other avian species

Table 2. Mammalian Results

Parameter Acute Chronic

Upper bound exposure (mg/kg-bw) 1754.4000 1754.4000

Adjusted toxicity value (mg/kg-bw) 3239.7043 456.8814

Ratio of exposure to toxicity 0.5415 3.8399
137

Conclusion*

Exposure through 

drinking water alone is a 

potential concern for 

mammals

Exposure through 

drinking water alone is a 

potential concern for 

mammals

Table 3. Avian Results

Parameter Acute Chronic

Upper bound exposure (mg/kg-bw) 8262.0000 8262.0000

Adjusted toxicity value (mg/kg-bw) 883.3654 21.2597

Ratio of exposure to acute toxicity 9.3529 388.6233

Conclusion*

Exposure through 

drinking water alone is a 

potential concern for 

birds

Exposure through 

drinking water alone is a 

potential concern for 

birds

*Conclusion is for drinking water exposure alone. This does not combine all routes of exposure. 

Therefore, when aggregated with other routes (i.e., diet, inhalation, dermal), pesticide exposure through 

drinking water may contribute to a total exposure that has potential for effects to non-target animals.
138

Appendix F – Risk Quotient Method and Levels of Concern

The Risk Quotient Method is the means by which the Environmental Fate and Effects 

Division (EFED) integrates the results of exposure and ecotoxicity data. In this method, both 

acute and chronic risk quotients are calculated by dividing exposure estimates by the most 

sensitive ecotoxicity values derived from the studies. Calculated risk quotients are then 

compared to OPP's levels of concern. The levels of concern are the criteria used by OPP to 

indicate potential risk to non-target organisms and the need to consider regulatory action. 

EFED has defined levels of concern for acute risk, potential restricted use, and for listed 

species. Risk presumptions, along with the corresponding risk quotients and levels of concern 

are summarized in the table below.

Levels of Concern for Assessed Taxa

Risk Presumption Risk Quotient Level of 

Concern

Birds

Acute Risk EEC/LC50 or LD50/sqft or LD50/day 0.5

Acute Restricted Use EEC/LC50 or LD50/sqft or LD50/day (or LD50 < 

50 mg/kg)

0.2

Acute Listed Species EEC/LC50 or LD50/sqft or LD50/day 0.1

Chronic Risk EEC/NOAEC 1

Mammals

Acute Risk EEC/LC50 or LD50/sqft or LD50/day 0.5

Acute Restricted Use EEC/LC50 or LD50/sqft or LD50/day (or LD50 < 

50 mg/kg)

0.2

Acute Listed Species EEC/LC50 or LD50/sqft or LD50/day 0.1

Chronic Risk EEC/NOAEC 1

Aquatic Animals

Acute Risk EEC/LC50 or EC50 0.5

Acute Restricted Use EEC/LC50 or EC50 0.1

Acute Listed Species EEC/LC50 or EC50 0.05

Chronic Risk EEC/NOAEC 1

Terrestrial and Semi-Aquatic Plants 

Acute Risk EEC/EC25 1

Acute Listed Species EEC/EC05 or NOAEC 1
139

Risk Presumption Risk Quotient Level of 

Concern

Aquatic Plants

Acute Risk EEC/EC50 1

Acute Listed Species EEC/EC05 or NOAEC 1
140

Appendix G – Surface Water Model Results and Sample Input and 

Outputs

Representative PRZM/EXAM Output: Pennsylvania Turf – Ground Application stored as PATurfGeco3.out

Chemical: Trinexapac

PRZM environment: PAturfSTD.txt modified Thuday, 23 February 2006 at 18:55:08

EXAMS environment: pond298.exv modified Tueday, 26 August 2008 at 06:14:07

Metfile: w14751.dvf modified Tueday, 26 August 2008 at 06:14:59

Water segment concentrations (ppb)

Year Peak 96 hr 21 Day 60 Day 90 Day Yearly

1961 1.04 0.98 0.76 0.55 0.55 0.20

1962 0.98 0.93 0.71 0.50 0.52 0.18

1963 0.98 0.93 0.71 0.48 0.50 0.17

1964 0.98 0.92 0.82 0.54 0.56 0.20

1965 0.98 0.92 0.70 0.50 0.51 0.17

1966 1.00 0.94 0.71 0.51 0.51 0.21

1967 1.04 0.99 0.76 0.53 0.54 0.22

1968 7.35 6.97 5.28 3.07 2.24 0.73

1969 1.03 0.97 0.75 0.57 0.57 0.27

1970 4.01 3.84 3.22 2.26 1.86 0.58

1971 1.03 0.98 0.74 0.54 0.54 0.20

1972 4.13 3.85 2.89 1.64 1.31 0.48

1973 5.01 4.76 3.57 2.07 1.55 0.58

1974 1.03 0.97 0.75 0.56 0.57 0.22

1975 1.02 0.96 0.84 0.57 0.58 0.21

1976 1.21 1.12 0.91 0.56 0.57 0.21

1977 0.99 0.94 0.72 0.53 0.54 0.19

1978 1.00 0.94 0.72 0.55 0.52 0.21

1979 1.00 0.94 0.73 0.50 0.52 0.20

1980 0.98 0.92 0.71 0.50 0.51 0.18

1981 0.98 0.92 0.70 0.48 0.49 0.17

1982 8.98 8.43 7.08 4.50 3.36 1.08

1983 1.28 1.22 0.97 0.86 0.82 0.34

1984 4.20 3.97 3.03 1.85 1.45 0.53

1985 1.05 1.00 0.79 0.56 0.58 0.23

1986 1.06 1.00 0.76 0.60 0.58 0.21

1987 1.71 1.58 1.15 0.80 0.65 0.27

1988 1.01 0.95 0.73 0.52 0.53 0.21

1989 1.05 1.00 0.81 0.62 0.61 0.23

1990 6.98 6.59 4.93 2.87 2.12 0.70

Sorted results

Prob. Peak 96 hr 21 Day 60 Day 90 Day Yearly

0.03 8.98 8.43 7.08 4.50 3.36 1.08

0.06 7.35 6.97 5.28 3.07 2.24 0.73

0.10 6.98 6.59 4.93 2.87 2.12 0.70

0.13 5.01 4.76 3.57 2.26 1.86 0.58

0.16 4.20 3.97 3.22 2.07 1.55 0.58

0.19 4.13 3.85 3.03 1.85 1.45 0.53

0.23 4.01 3.84 2.89 1.64 1.31 0.48

0.26 1.71 1.58 1.15 0.86 0.82 0.34

0.29 1.28 1.22 0.97 0.80 0.65 0.27

0.32 1.21 1.12 0.91 0.62 0.61 0.27

0.35 1.06 1.00 0.84 0.60 0.58 0.23

0.39 1.05 1.00 0.82 0.57 0.58 0.23

0.42 1.05 1.00 0.81 0.57 0.58 0.22

0.45 1.04 0.99 0.79 0.56 0.57 0.22

0.48 1.04 0.98 0.76 0.56 0.57 0.21

0.52 1.03 0.98 0.76 0.56 0.57 0.21

0.55 1.03 0.97 0.76 0.55 0.56 0.21

0.58 1.03 0.97 0.75 0.55 0.55 0.21

0.61 1.02 0.96 0.75 0.54 0.54 0.21

0.65 1.01 0.95 0.74 0.54 0.54 0.21

0.68 1.00 0.94 0.73 0.53 0.54 0.20

0.71 1.00 0.94 0.73 0.53 0.53 0.20

0.74 1.00 0.94 0.72 0.52 0.52 0.20

0.77 0.99 0.94 0.72 0.51 0.52 0.20

0.81 0.98 0.93 0.71 0.50 0.52 0.19

0.84 0.98 0.93 0.71 0.50 0.51 0.18

0.87 0.98 0.92 0.71 0.50 0.51 0.18

0.90 0.98 0.92 0.71 0.50 0.51 0.17

0.94 0.98 0.92 0.70 0.48 0.50 0.17

0.97 0.98 0.92 0.70 0.48 0.49 0.17

0.10 6.78 6.41 4.79 2.81 2.10 0.69

Average of y 0.32

Inputs generated by pe5.pl - Novemeber 2006

Data used for this run:

Output File: PATurfGeco3

Metfile: w14751.dvf

PRZM scenario: PAturfSTD.txt

EXAMS environment file: pond298.exv

Chemical Name: Trinexapac

Description Variable NaValue Units Comments

Molecular weight mwt 252.3 g/mol

Henry's Law Const. henry 5.27E-10 atm-m^3/mol

Vapor Pressure vapr 1.62E-05 torr

Solubility sol 10200 mg/L

Kd Kd mg/L

Koc Koc 416 mg/L

Photolysis half-life kdp 22.8 days Half-life

Aerobic Aquatic Metabolism kbacw 17.4 days Halfife

Anaerobic Aquatic Metabolism kbacs 533 days Halfife

Aerobic Soil Metabolism asm 5.2 days Halfife

Hydrolysis: pH 7 0 days Half-life

Method: CAM 2 integer See PRZM manual

Incorporation Depth: DEPI cm

Application Rate: TAPP 1.53 kg/ha

Application Efficiency: APPEFF 0.99 fraction

Spray Drift DRFT 0.01 fraction of application rate applied to pond

Application Date Date 4-Jan dd/mm or dd/mmm or dd-mm or dd-mmm

Interval 1 interval 56 days Set to 0 or delete line for single app

app. rate 1 apprate 1.53 kg/ha

Record 17: FILTRA

IPSCND 2

UPTKF

Record 18: PLVKRT

PLDKRT

FEXTRC 0.5

Flag for Index Res. Run IR EPA Pond

Flag for runoff calc. RUNOFF none none, monthly or total(average of entire run)
141

Appendix H – TerrPlant Output

Sugarcane – 1 ground app at 0.31 lb ai/A

Table 1. Chemical Identity.

Parameter User Inputs

Chemical Name Trinexapac-ethyl

PC code 112602

Use Herbicide for grasses

Application Method Spray

Application Form Liquid 

Solubility in Water 

(ppm) 10200

Table 2. Input parameters used to derive EECs.

Input Parameter Symbol

Value (user 

inputs) Units

Application Rate A 0.31

Incorporation I 1 none

Runoff Fraction R 0.05 none

Drift Fraction D 0.01 none

Table 3. EECs for Trinexapac-ethyl. Units in .

Description Equation EEC

Runoff to dry areas (A/I)*R 0.0155

Runoff to semi-aquatic areas (A/I)*R*10 0.155

Spray drift A*D 0.0031

Total for dry areas ((A/I)*R)+(A*D) 0.0186

Total for semi-aquatic areas ((A/I)*R*10)+(A*D) 0.1581

Table 4. Plant survival and growth data used for RQ derivation. Units are in . All values are user inputs

Seedling Emergence Vegetative Vigor

Plant type EC25 NOAEC EC25 NOAEC 

Monocot 0.301 0.094 0.294 0.0425

Dicot 0.22 0.094 0.267 0.085

Table 5. RQ values for plants in dry and semi-aquatic areas exposed to Trinexapac-ethyl through runoff 

and/or spray drift.*

Plant Type Listed Status Dry Semi-Aquatic Spray Drift

Monocot non-listed <0.1 0.53 <0.1

Monocot listed 0.20 1.68 <0.1

Dicot non-listed <0.1 0.72 <0.1

Dicot listed 0.20 1.68 <0.1
142

*If RQ > 1.0, the LOC is exceeded, resulting in potential for risk to that plant group.
143

Appendix I – T-REX Output

Cereals – 1 app at 0.11 lb ai/A

Table X. Upper Bound Kenaga, Acute Avian Dose-Based Risk Quotients

Size 

Class

(grams)

Adjusted

LD50

EECs and RQs

Short Grass Tall Grass Broadleaf 

Plants

Fruits/Pods

/Seeds Arthropods Granivore

EEC RQ EEC RQ EEC RQ EEC RQ EEC RQ EEC RQ

20 883.37 30.07 0.03 13.78 0.02 16.91 0.02 1.88 0.00 11.78 0.01 0.42 0.00

100 1124.57 17.15 0.02 7.86 0.01 9.64 0.01 1.07 0.00 6.72 0.01 0.24 0.00

1000 1588.50 7.68 0.00 3.52 0.00 4.32 0.00 0.48 0.00 3.01 0.00 0.11 0.00

Table X. Upper Bound Kenaga, Subacute Avian Dietary Based Risk Quotients

LC50

EECs and RQs

Short Grass Tall Grass Broadleaf 

Plants Fruits/Pods/Seeds Arthropods

EEC RQ EEC RQ EEC RQ EEC RQ EEC RQ

0 26.40 N/A 12.10 N/A 14.85 N/A 1.65 N/A 10.34 N/A

Size class not used for dietary risk quotients 

Table X. Upper Bound Kenaga, Chronic Avian Dietary Based Risk Quotients

NOAEC 

(ppm)

EECs and RQs

Short Grass Tall Grass Broadleaf 

Plants Fruits/Pods/Seeds Arthropods

EEC RQ EEC RQ EEC RQ EEC RQ EEC RQ

200 26.40 0.13 12.10 0.06 14.85 0.07 1.65 0.01 10.34 0.05

Size class not used for dietary risk quotients

Table X. Upper Bound Kenaga, Acute Mammalian Dose-Based Risk Quotients 

Size Adjusted EECs and RQs
144

Class

(grams)

LD50

Short Grass Tall Grass Broadleaf 

Plants

Fruits/Pods/S

eeds Arthropods Granivore

EEC RQ EEC RQ EEC RQ EEC RQ EEC RQ EEC RQ

15 9257.26 25.17 0.00 11.54 0.00 14.16 0.00 1.57 0.00 9.86 0.0011 0.35 4E-05

35 7490.11 17.40 0.00 7.97 0.00 9.79 0.00 1.09 0.00 6.81 0.0009 0.24 3E-05

1000 3239.70 4.03 0.00 1.85 0.00 2.27 0.00 0.25 0.00 1.58 0.0005 0.06 2E-05

Table X. Upper Bound Kenaga, Acute Mammalian Dietary Based Risk Quotients

LC50 

(ppm)

EECs and RQs

Short Grass Tall Grass Broadleaf Plants Fruits/Pods/Seeds Arthropods

EEC RQ EEC RQ EEC RQ EEC RQ EEC RQ

0 26.40 N/A 12.10 N/A 14.85 N/A 1.65 N/A 10.34 N/A

Size class not used for dietary risk quotients

Table X. Upper Bound Kenaga, Chronic Mammalian Dietary Based Risk Quotients

NOAE

C (ppm)

EECs and RQs

Short Grass Tall Grass Broadleaf Plants Fruits/Pods/Seeds/

Large Insects Arthropods

EEC RQ EEC RQ EEC RQ EEC RQ EEC RQ

11880 26.40 0.00 12.10 0.00 14.85 0.00 1.65 0.00 10.34 0.00

Size class not used for dietary risk quotients 

Table X. Upper Bound Kenaga, Chronic Mammalian Dose-Based Risk Quotients

Size 

Class

(grams)

Adjusted 

NOAEL

EECs and RQs

Short Grass Tall Grass Broadleaf 

Plants

Fruits/Pods/See

ds Arthropods Granivore

EEC RQ EEC RQ EEC RQ EEC RQ EEC RQ EEC RQ

15 1305.51 25.17 0.02 11.54 0.01 14.16 0.01 1.57 0.00 9.86 0.01 0.35 0.00

35 1056.30 17.40 0.02 7.97 0.01 9.79 0.01 1.09 0.00 6.81 0.01 0.24 0.00

1000 456.88 4.03 0.01 1.85 0.00 2.27 0.00 0.25 0.00 1.58 0.00 0.06 0.00
145

APPENDIX J – Listed Species Analysis

Table J-1. “No Effects” (Direct and Indirect Effects) Determination for Listed Species 

Outside the Geographical Range of Trinexapac-Ethyl Uses

Common Name Scientific Name Status Taxon

Toad, Wyoming

Bufo baxteri 

(=hemiophrys) E Amphibian

Guajon

Eleutherodactylus 

cooki T Amphibian

Coqui, Golden

Eleutherodactylus 

jasperi T Amphibian

Llanero coqui

Eleutherodactylus 

juanariveroi E Amphibian

Toad, Puerto Rican 

Crested Peltophryne lemur T Amphibian

Salamander, Cheat 

Mountain Plethodon nettingi T Amphibian

Hawk, Puerto Rican SharpshinnedAccipiter striatus 

venator E Bird

Warbler, nightingale reed 

(old world warbler) Acrocephalus luscinia E Bird

Blackbird, Yellowshouldered Agelaius xanthomus E Bird

Parrot, Puerto Rican Amazona vittata E Bird

Sparrow, San Clemente 

Sage

Amphispiza belli 

clementeae T Bird

Hawk, Puerto Rican BroadwingedButeo platypterus 

brunnescens E Bird

Nightjar, Puerto Rico

Caprimulgus 

noctitherus E Bird

Bobwhite, Masked

Colinus virginianus 

ridgwayi E Bird

Pigeon, Puerto Rican Plain

Columba inornata 

wetmorei E Bird

Crow, Mariana Corvus kubaryi E Bird

Moorhen, Mariana 

Common

Gallinula chloropus 

guami E Bird

Kingfisher, Guam 

Micronesian

Halcyon cinnamomina 

cinnamomina E Bird

Shrike, San Clemente 

Loggerhead

Lanius ludovicianus 

mearnsi E Bird
146

Megapode, Micronesian 

(La Perouse's)

Megapodius 

laperouse E Bird

Towhee, Inyo Brown

Pipilo crissalis 

eremophilus T Bird

Eider, Steller's Polysticta stelleri T Bird

Rail, Light-footed Clapper

Rallus longirostris 

levipes E Bird

Rail, Guam Rallus owstoni E Bird

White-eye, Bridled (Nossa)

Zosterops 

conspicillatus 

conspicillatus E Bird

White-eye, Rota Bridled Zosterops rotensis E Bird

Elktoe, Appalachian

Alasmidonta 

raveneliana E Bivalve

Rock-pocketbook, 

Ouachita (=Wheeler's pm) Arkansia wheeleri E Bivalve

Combshell, Southern 

(=Penitent mussel) Epioblasma penita E Bivalve

Fatmucket, Arkansas Lampsilis powelli T Bivalve

Alabama pearlshell

Margaritifera 

marrianae E Bivalve

Mussel, Southern 

Clubshell Pleurobema decisum E Bivalve

Mussel, Flat Pigtoe 

(=Marshall's Mussel) Pleurobema marshalli E Bivalve

Stirrupshell Quadrula stapes E Bivalve

Cypress, Santa Cruz Cupressus abramsiana E Conf/cycds

Fairy Shrimp, San Diego

Branchinecta 

sandiegonensis E Crustacean

Isopod, Socorro

Thermosphaeroma 

thermophilus E Crustacean

Thornmint, San Diego

Acanthomintha 

ilicifolia T Dicot

Thornmint, San Mateo

Acanthomintha 

obovata ssp. duttonii E Dicot

Monkshood, Northern 

Wild

Aconitum 

noveboracense T Dicot

Blue-star, Kearney's Amsonia kearneyana E Dicot

Rock-cress, Hoffmann's Arabis hoffmannii E Dicot

Rock-cress, Small

Arabis perstellata E. L. 

Braun var. perstellata 

Fernald E Dicot
147

Rock-cress, Shale Barren Arabis serotina E Dicot

San Francisco manzanita

Arctostaphylos 

franciscana E Dicot

Manzanita, Del Mar

Arctostaphylos 

glandulosa ssp. 

crassifolia E Dicot

Manzanita, Presidio 

(=Raven's)

Arctostaphylos 

hookeri var. ravenii E Dicot

Manzanita, Morro

Arctostaphylos 

morroensis T Dicot

Manzanita, Ione

Arctostaphylos 

myrtifolia T Dicot

Manzanita, Pallid Arctostaphylos pallida T Dicot

Sandwort, Cumberland

Arenaria 

cumberlandensis E Dicot

Sandwort, Bear Valley Arenaria ursina T Dicot

Poppy, Sacramento Prickly

Argemone pleiacantha 

ssp. pinnatisecta E Dicot

Milkweed, Welsh's Asclepias welshii T Dicot

Milk-vetch, Cushenbury Astragalus albens E Dicot

Milk-vetch, Applegate's Astragalus applegatei E Dicot

Ground-plum, Guthrie's Astragalus bibullatus E Dicot

Milk-vetch, Braunton's Astragalus brauntonii E Dicot

Milk-vetch, Sentry

Astragalus 

cremnophylax var. 

cremnophylax E Dicot

Milk-vetch, Lane 

Mountain Astragalus jaegerianus E Dicot

Milk-vetch, Fish Slough

Astragalus 

lentiginosus var. 

piscinensis T Dicot

Milk-vetch, Osterhout Astragalus osterhoutii E Dicot

Milk-vetch, Ash Meadows Astragalus phoenix T Dicot

Milk-vetch, Ventura Marsh

Astragalus 

pycnostachyus var. 

lanosissimus E Dicot

Milk-vetch, Jesup's

Astragalus robbinsii 

var. jesupi E Dicot

Auerodendron 

pauciflorum (ncn)

Auerodendron 

pauciflorum E Dicot

Baccharis, Encinitas Baccharis vanessae T Dicot

Palo de Ramon Banara vanderbiltii E Dicot
148

Rattleweed, Hairy Baptisia arachniferaE Dicot

Barberry, Island

Berberis pinnata ssp. 

insularis

E Dicot

Capa Rosa Callicarpa amplaE Dicot

Poppy-mallow, Texas Callirhoe scabriusculaE Dicot

Calyptranthes Thomasiana 

(ncn)

Calyptranthes 

thomasiana

E Dicot

Morning-glory, Stebbins Calystegia stebbinsiiE Dicot

Paintbrush, Ash-grey 

Indian Castilleja cinereaT Dicot

Paintbrush, San Clemente 

Island Indian Castilleja grisea

E Dicot

Paintbrush, Soft-leaved Castilleja mollisE Dicot

Ceanothus, Coyote Ceanothus ferrisaeE Dicot

Ceanothus, Pine Hill Ceanothus roderickiiE Dicot

Centaury, Spring-loving

Centaurium 

namophilum

T Dicot

Mountain-mahogany, 

Catalina Island Cercocarpus traskiaeE Dicot

Prickly-apple, Fragrant

Cereus eriophorus 

var. fragrans

E Dicot

Chamaecrista glandulosa 

(ncn)

Chamaecrista 

glandulosa var. 

mirabilis

E Dicot

Spineflower, Howell's Chorizanthe howelliiE Dicot

Spineflower, Orcutt's

Chorizanthe 

orcuttiana

E Dicot

Spineflower, Ben Lomond

Chorizanthe pungens 

var. hartwegiana

E Dicot

Spineflower, Scotts Valley

Chorizanthe robusta 

var. hartwegii

E Dicot

Thistle, Fountain

Cirsium fontinale var. 

fontinale

E Dicot

Thistle, Sacramento 

Mountains Cirsium vinaceum

T Dicot

Clarkia, Presidio Clarkia franciscanaE Dicot

Clarkia, Springville Clarkia springvillensisT Dicot

Rosemary, Etonia Conradina etoniaE Dicot

Rosemary, Apalachicola Conradina glabraE Dicot

Cordia bellonis (ncn) Cordia bellonisE Dicot

Palo de Nigua Cornutia obovataE Dicot

Cactus, Nellie Cory Coryphantha minimaE Dicot
149

Cactus, Bunched Cory Coryphantha ramillosa T Dicot

Cactus, Pima Pineapple

Coryphantha scheeri 

var. robustispina E Dicot

Higuero De Sierra

Crescentia 

portoricensis E Dicot

Cat's-eye, Terlingua Creek Cryptantha crassipes E Dicot

Daphnopsis hellerana 

(ncn) Daphnopsis hellerana E Dicot

Pawpaw, Beautiful

Deeringothamnus 

pulchellus E Dicot

Pawpaw, Rugel's

Deeringothamnus 

rugelii E Dicot

Tarplant, Otay

Deinandra 

(=Hemizonia) 

conjugens T Dicot

Tarplant, Gaviota

Deinandra increscens 

ssp. villosa E Dicot

Larkspur, San Clemente 

Island

Delphinium 

variegatum ssp. 

kinkiense E Dicot

Mint, Garrett's

Dicerandra 

christmanii E Dicot

Dudleya, Conejo

Dudleya abramsii ssp. 

parva T Dicot

Dudleya, Marcescent

Dudleya cymosa ssp. 

marcescens T Dicot

Dudleya, Santa Monica 

Mountains

Dudleya cymosa ssp. 

ovatifolia T Dicot

Dudleya, Santa Cruz Island Dudleya nesiotica T Dicot

Dudleya, Santa Clara 

Valley Dudleya setchellii E Dicot

Liveforever, Laguna Beach Dudleya stolonifera T Dicot

Liveforever, Santa Barbara

Island Dudleya traskiae E Dicot

Dudleya, Verity's Dudleya verityi T Dicot

Cactus, Chisos Mountain 

Hedgehog

Echinocereus 

chisoensis var. 

chisoensis T Dicot

Pitaya, Davis' Green

Echinocereus 

viridiflorus var. davisii E Dicot

Sunray, Ash Meadows

Enceliopsis nudicaulis 

var. corrugata T Dicot
150

Yerba Santa, Lompoc Eriodictyon capitatum E Dicot

Buckwheat, Ione (incl. 

Irish Hill)

Eriogonum apricum 

(incl. var. prostratum) E Dicot

Buckwheat, Southern 

Mountain Wild

Eriogonum kennedyi 

var. austromontanum T Dicot

Buckwheat, Cushenbury

Eriogonum 

ovalifolium var. 

vineum E Dicot

Buckwheat, Steamboat

Eriogonum 

ovalifolium var. 

williamsiae E Dicot

Sunflower, San Mateo 

Woolly Eriophyllum latilobum E Dicot

Snakeroot Eryngium cuneifolium E Dicot

Wallflower, Contra Costa

Erysimum capitatum 

var. angustatum E Dicot

Wallflower, Ben Lomond Erysimum teretifolium E Dicot

Uvillo

Eugenia 

haematocarpa E Dicot

Eugenia Woodburyana Eugenia woodburyana E Dicot

Mustard, Penland Alpine 

Fen Eutrema penlandii T Dicot

Flannelbush, Pine Hill

Fremontodendron 

californicum ssp. 

decumbens E Dicot

Flannelbush, Mexican

Fremontodendron 

mexicanum E Dicot

Bedstraw, Island Galium buxifolium E Dicot

Bedstraw, El Dorado

Galium californicum 

ssp. sierrae E Dicot

Gesneria pauciflora (ncn) Gesneria pauciflora T Dicot

Gilia, Hoffmann's SlenderfloweredGilia tenuiflora ssp. 

hoffmannii E Dicot

Goetzea, Beautiful 

(Matabuey) Goetzea elegans E Dicot

Gumplant, Ash Meadows

Grindelia fraxinopratensis T Dicot

Stickseed, Showy Hackelia venusta E Dicot

Chumbo, Higo Harrisia portoricensis T Dicot

Pennyroyal, Todsen's Hedeoma todsenii E Dicot

Rush-rose, Island

Helianthemum 

greenei T Dicot
151

Rush-pea, Slender

Hoffmannseggia 

tenella E Dicot

Heather, Mountain 

Golden Hudsonia montana T Dicot

Daisy, Lakeside Hymenoxys herbacea T Dicot

Holly, Cook's Ilex cookii E Dicot

Ilex sintenisii (ncn) Ilex sintenisii E Dicot

Mallow, Peter's Mountain Iliamna corei E Dicot

Pagosa Skyrocket Ipomopsis polyantha E Dicot

Ipomopsis, Holy Ghost

Ipomopsis sanctispiritus E Dicot

Ivesia, Ash Meadows

Ivesia kingii var. 

eremica T Dicot

Leptocereus grantianus 

(ncn)

Leptocereus 

grantianus E Dicot

Bladderpod, San 

Bernardino Mountains

Lesquerella kingii ssp. 

bernardina E Dicot

Bladderpod, White Lesquerella pallida E Dicot

Bladderpod, Spring Creek Lesquerella perforata E Dicot

Bladderpod, Kodachrome Lesquerella tumulosa E Dicot

Lessingia, San Francisco

Lessingia germanorum 

(=L.g. var. 

germanorum) E Dicot

Meadowfoam, Butte 

County

Limnanthes floccosa 

ssp. californica E Dicot

Woodland-star, San 

Clemente Island

Lithophragma 

maximum E Dicot

Broom, San Clemente 

Island

Lotus dendroideus 

ssp. traskiae E Dicot

Lyonia truncata var. 

proctorii (ncn)

Lyonia truncata var. 

proctorii E Dicot

Bush-mallow, San 

Clemente Island

Malacothamnus

clementinus E Dicot

Bush-mallow, Santa Cruz 

Island

Malacothamnus 

fasciculatus var. 

nesioticus E Dicot

Malacothrix, Santa Cruz 

Island Malacothrix indecora E Dicot

Malacothrix, Island Malacothrix squalida E Dicot

Blazing Star, Ash Meadows Mentzelia leucophylla T Dicot

Mitracarpus Maxwelliae

Mitracarpus 

maxwelliae E Dicot
152

Mitracarpus Polycladus

Mitracarpus 

polycladus E Dicot

Monardella, Willowy

Monardella linoides 

ssp. viminea E Dicot

Myrcia Paganii Myrcia paganii E Dicot

Niterwort, Amargosa Nitrophila mohavensis E Dicot

Evening-primrose, Eureka 

Valley

Oenothera avita ssp. 

eurekensis E Dicot

Palo de Rosa

Ottoschulzia 

rhodoxylon E Dicot

Oxytheca, Cushenbury

Oxytheca parishii var. 

goodmaniana E Dicot

Stonecrop, Lake County

Parvisedum 

leiocarpum E Dicot

Cactus, Brady Pincushion Pediocactus bradyi E Dicot

Cactus, San Rafael Pediocactus despainii E Dicot

Cactus, Winkler Pediocactus winkleri T Dicot

Parachute Beardtongue Penstemon debilis T Dicot

Beardtongue, Penland Penstemon penlandii E Dicot

Pentachaeta, White-rayed

Pentachaeta 

bellidiflora E Dicot

Pentachaeta, Lyon's Pentachaeta lyonii E Dicot

Peperomia, Wheeler's Peperomia wheeleri E Dicot

Phacelia, Island

Phacelia insularis ssp. 

insularis E Dicot

Phlox, Yreka Phlox hirsuta E Dicot

Cactus, Key Tree Pilosocereus robinii E Dicot

Aster, Ruth's Golden Pityopsis ruthii E Dicot

Chupacallos

Pleodendron 

macranthum E Dicot

Mint, San Diego Mesa Pogogyne abramsii E Dicot

Mint, Otay Mesa Pogogyne nudiuscula E Dicot

Polygonum, Scott's Valley Polygonum hickmanii E Dicot

Buttercup, Autumn

Ranunculus aestivalis 

(=acriformis) E Dicot

Pitcher-plant, Alabama 

Canebrake

Sarracenia rubra 

alabamensis E Dicot

Schoepfia arenaria (ncn) Schoepfia arenaria T Dicot

Groundsel, San Francisco 

Peaks Senecio franciscanus T Dicot

Hayun Lagu (Tronkon 

Guafi) Serianthes nelsonii E Dicot
153

Rock-cress, Santa Cruz 

Island Sibara filifolia E Dicot

Checker-mallow, 

Wenatchee Mountains

Sidalcea oregana var. 

calva E Dicot

Checker-mallow, Pedate Sidalcea pedata E Dicot

Erubia

Solanum 

drymophilum E Dicot

Goldenrod, Blue Ridge Solidago spithamaea T Dicot

Cobana Negra Stahlia monosperma T Dicot

Jewelflower, Metcalf 

Canyon

Streptanthus albidus 

ssp. albidus E Dicot

Palo de Jazmin Styrax portoricensis E Dicot

Taraxacum, California

Taraxacum 

californicum E Dicot

Palo Colorado 

(Ternstroemia luquillensis)

Ternstroemia 

luquillensis E Dicot

Ternstroemia subsessilis 

(ncn)

Ternstroemia 

subsessilis E Dicot

Mustard, Slender-petaled

Thelypodium 

stenopetalum E Dicot

Fringepod, Santa Cruz

Island

Thysanocarpus 

conchuliferus E Dicot

Bariaco Trichilia triacantha E Dicot

Vervain, California Verbena californica T Dicot

Crownbeard, Big-leaved Verbesina dissita T Dicot

Vernonia Proctorii (ncn) Vernonia proctorii E Dicot

Prickly-ash, St. Thomas

Zanthoxylum 

thomasianum E Dicot

Fern, Adiantum vivesii Adiantum vivesii E Ferns

Tree Fern, Elfin

Cyathea 

dryopteroides E Ferns

Fern, Elaphoglossum 

serpens

Elaphoglossum 

serpens E Ferns

Quillwort, Mat-forming Isoetes tegetiformans E Ferns

Polystichum calderonense 

(ncn)

Polystichum 

calderonense E Ferns

Tectaria Estremerana Tectaria estremerana E Ferns

Fern, Thelypteris 

inabonensis

Thelypteris 

inabonensis E Ferns

Fern, Alabama StreaksorusThelypteris pilosa var. 

alabamensis T Ferns
154

Fern, Thelypteris 

verecunda Thelypteris verecunda E Ferns

Fern, Thelypteris 

yaucoensis Thelypteris yaucoensis E Ferns

Sucker, Shortnose

Chasmistes 

brevirostris E Fish

Cui-ui Chasmistes cujus E Fish

Laurel dace Chrosomus aylori E Fish

Sculpin, Pygmy

Cottus paulus 

(=pygmaeus) T Fish

Springfish, Railroad Valley Crenichthys nevadae T Fish

Pupfish, Leon Springs Cyprinodon bovinus E Fish

Pupfish, Devils Hole Cyprinodon diabolis E Fish

Pupfish, Comanche 

Springs Cyprinodon elegans E Fish

Pupfish, Ash Meadows 

Amargosa

Cyprinodon 

nevadensis mionectes E Fish

Pupfish, Warm Springs

Cyprinodon 

nevadensis pectoralis E Fish

Pupfish, Owens Cyprinodon radiosus E Fish

Darter, Vermilion

Etheostoma 

chermocki E Fish

Darter, Relict

Etheostoma 

chienense E Fish

Darter, Watercress Etheostoma nuchale E Fish

Darter, Maryland Etheostoma sellare E Fish

Darter, Boulder Etheostoma wapiti E Fish

Gambusia, Big Bend Gambusia gaigei E Fish

Gambusia, Clear Creek Gambusia heterochir E Fish

Stickleback, Unarmored 

Threespine

Gasterosteus 

aculeatus williamsoni E Fish

Chub, Mohave Tui

Gila bicolor 

mohavensis E Fish

Chub, Owens Tui Gila bicolor snyderi E Fish

Chub, Hutton Tui Gila bicolor ssp. T Fish

Chub, Sonora Gila ditaenia T Fish

Chub, Chihuahua Gila nigrescens T Fish

Silverside, Waccamaw Menidia extensa T Fish

Dace, Moapa Moapa coriacea E Fish

Shiner, Palezone Notropis albizonatus E Fish

Madtom, Smoky Noturus baileyi E Fish

Chucky Madtom Noturus crypticus E Fish
155

Madtom, Pygmy Noturus stanauli E Fish

Trout, Little Kern Golden

Oncorhynchus 

aguabonita whitei T Fish

Trout, Gila Oncorhynchus gilae E Fish

Logperch, Roanoke Percina rex E Fish

Dace, Independence 

Valley Speckled

Rhinichthys osculus 

lethoporus E Fish

Dace, Ash Meadows 

Speckled

Rhinichthys osculus 

nevadensis E Fish

Dace, Clover Valley 

Speckled

Rhinichthys osculus 

oligoporus E Fish

Dace, Foskett Speckled

Rhinichthys osculus 

ssp. T Fish

Dace, Kendall Warm 

Springs

Rhinichthys osculus 

thermalis E Fish

Salmon, Atlantic Salmo salar E Fish

Cavefish, Alabama

Speoplatyrhinus 

poulsoni E Fish

Snail, Painted Snake Coiled 

Forest Anguispira picta T Gastropod

Riversnail, Anthony's Athearnia anthonyi E Gastropod

Elimia, Lacy Elimia crenatella T Gastropod

Snail, Newcomb's Erinna newcombi T Gastropod

Rocksnail, Plicate Leptoxis plicata E Gastropod

Snail, Noonday

Mesodon clarki 

nantahala T Gastropod

Shagreen, Magazine 

Mountain

Mesodon 

magazinensis T Gastropod

Snail, Stock Island Tree

Orthalicus reses (not 

incl. nesodryas) T Gastropod

Ambersnail, Kanab

Oxyloma haydeni 

kanabensis E Gastropod

Snail, Virginia Fringed 

Mountain

Polygyriscus 

virginianus E Gastropod

Snail, Armored

Pyrgulopsis 

(=Marstonia) pachyta E Gastropod

Springsnail, Chupadera

Pyrgulopsis 

chupaderae E Gastropod

Springsnail, Socorro

Pyrgulopsis 

neomexicana E Gastropod

Marstonia, Royal (=Royal 

Snail)

Pyrgulopsis 

ogmorhaphe E Gastropod
156

Snail, Chittenango Ovate 

Amber

Succinea 

chittenangoensis T Gastropod

Snail, Flat-spired ThreetoothedTriodopsis 

platysayoides T Gastropod

Springsnail, Alamosa Tryonia alamosae E Gastropod

Naucorid, Ash Meadows Ambrysus amargosus T Insect

Butterfly, Lange's 

Metalmark

Apodemia mormo 

langei E Insect

Beetle, Coffin Cave Mold Batrisodes texanus E Insect

Beetle, Northeastern 

Beach Tiger

Cicindela dorsalis 

dorsalis T Insect

Beetle, Ohlone Tiger Cicindela ohlone E Insect

Beetle, Puritan Tiger Cicindela puritana T Insect

Butterfly, El Segundo Blue

Euphilotes battoides 

allyni E Insect

Butterfly, Bay Checkerspot 

(Wright's euphydryas)

Euphydryas editha 

bayensis T Insect

Butterfly, Palos Verdes 

Blue

Glaucopsyche 

lygdamus 

palosverdesensis E Insect

Butterfly, Schaus 

Swallowtail

Heraclides 

aristodemus 

ponceanus E Insect

Skipper, Pawnee Montane

Hesperia leonardus 

montana T Insect

Butterfly, Lotis Blue

Lycaeides 

argyrognomon lotis E Insect

Butterfly, Saint Francis' 

Satyr

Neonympha mitchellii 

francisci E Insect

Beetle, Mount Hermon 

June Polyphylla barbata E Insect

Skipper, Laguna Mountain Pyrgus ruralis lagunae E Insect

Grasshopper, Zayante 

Band-winged

Trimerotropis 

infantilis E Insect

Mountain Beaver, Point 

Arena Aplodontia rufa nigra E Mammal

Whale, Bowhead Balaena mysticetus E Mammal

Whale, Blue

Balaenoptera 

musculus E Mammal

Otter, Northern Sea Enhydra lutris kenyoni T Mammal

Whale, North Pacific right Eubalaena japonica E Mammal
157

Vole, Amargosa

Microtus californicus 

scirpensis E Mammal

Woodrat, Key Largo

Neotoma floridana 

smalli E Mammal

Deer, Key

Odocoileus virginianus 

clavium E Mammal

Rice Rat (=Silver Rice Rat)

Oryzomys palustris 

natator E Mammal

Mouse, Pacific Pocket

Perognathus 

longimembris 

pacificus E Mammal

Mouse, Key Largo Cotton

Peromyscus 

gossypinus 

allapaticola E Mammal

Mouse, Anastasia Island 

Beach

Peromyscus 

polionotus phasma E Mammal

Bat, Mariana Fruit 

(=Mariana Flying Fox)

Pteropus mariannus 

mariannus T Mammal

Bat, Little Mariana Fruit Pteropus tokudae E Mammal

Squirrel, Delmarva 

Peninsula Fox Sciurus niger cinereus E Mammal

Rabbit, Lower Keys Marsh

Sylvilagus palustris 

hefneri E Mammal

Fox, Santa Catalina Island

Urocyon littoralis 

catalinae E Mammal

Fox, San Miguel Island

Urocyon littoralis 

littoralis E Mammal

Fox, Santa Cruz Island

Urocyon littoralis 

santacruzae E Mammal

Fox, Santa Rosa Island

Urocyon littoralis 

santarosae E Mammal

Aristida chaseae (ncn) Aristida chaseae E Monocot

Pelos del Diablo Aristida portoricensis E Monocot

Brodiaea, Chinese Camp Brodiaea pallida T Monocot

Manaca, palma de Calyptronoma rivalis T Monocot

Sedge, Golden Carex lutea E Monocot

Cranichis Ricartii Cranichis ricartii E Monocot

Walnut, Nogal Juglans jamaicensis E Monocot

Lepanthes eltorensis (ncn) Lepanthes eltoroensis E Monocot

Bluegrass, San Bernardino Poa atropurpurea E Monocot

Pondweed, Little Aguja 

Creek

Potamogeton 

clystocarpus E Monocot
158

Beaked-rush, Knieskern's

Rhynchospora 

knieskernii T Monocot

Grass, Eureka Dune Swallenia alexandrae E Monocot

Anole, Culebra Island 

Giant Anolis roosevelti E Reptile

Sea turtle, loggerhead Caretta caretta E/T Reptile

Sea turtle, green Chelonia mydas E/T Reptile

Sea turtle, leatherback Dermochelys coriacea E Reptile

Boa, Puerto Rican Epicrates inornatus E Reptile

Boa, Virgin Islands Tree

Epicrates monensis 

granti E Reptile

Sea turtle, hawksbill

Eretmochelys 

imbricata E Reptile

Sea turtle, Kemp's ridley Lepidochelys kempii E Reptile

Sea turtle, olive ridley Lepidochelys olivacea T Reptile

Snake, Atlantic Salt Marsh

Nerodia clarkii 

taeniata T Reptile

Turtle, Plymouth RedbelliedPseudemys 

rubriventris bangsi E Reptile

Snake, San Francisco 

Garter

Thamnophis sirtalis 

tetrataenia E Reptile

Lizard, Island Night Xantusia riversiana T Reptile

Table J-2. “No Effects” (Direct Effects Only) Determination for Listed Species Within 

Geographical Range of Trinexapac-Ethyl Uses, Based on Species Ecology and Biology

Common Name Scientific Name Status Taxon Exclusion Rationale Reference

Common Name Scientific Name Status Taxon Exclusion Rationale Reference

Salamander, 

Texas Blind

Typhlomolge 

rathbuni E Amphibian

Lives in caves, which are 

unlikely to be affected by 

trinexapac-ethyl 

applications

USFWS. 1996. San Marcos and Comal 

Springs and Associated Aquatic 

ecosystems recovery plan. United States 

Fish and Wildlife Service.

Spider, Kauai 

Cave Wolf

Adelocosa 

anops E Arachnid

Lives in caves and lava 

tubes, which are unlikely 

to be affected by 

trinexapac-ethyl 

applications

USFWS. 2006. Final recovery plan for 

the Kaua'I cave arthropods. United States 

Fish and Wildlife Service.

Meshweaver, 

Robber Baron 

Cave Cicurina baronia E Arachnid

Entire life is spent 

underground and is 

unlikely to be affected by 

trinexapac-ethyl 

applications

USFWS. 2011. Bexar County Karst 

Invertebrates Recovery Plan. United 

States Fish and Wildlife Service.

Meshweaver, 

Madla's Cave Cicurina madla E Arachnid

Lives in caves, which are 

unlikely to be affected by 

trinexapac-ethyl 

applications

USFWS. 2011. Bexar County Karst 

Invertebrates Recovery Plan. United 

States Fish and Wildlife Service.
159

Meshweaver, 

Braken Bat 

Cave Cicurina venii E Arachnid

Lives in caves, which are 

unlikely to be affected by 

trinexapac-ethyl 

applications

USFWS. 2011. Bexar County Karst 

Invertebrates Recovery Plan. United 

States Fish and Wildlife Service.

Meshweaver, 

Government 

Canyon Bat 

Cave Cicurina vespera E Arachnid

Lives in caves, which are 

unlikely to be affected by 

trinexapac-ethyl 

applications

USFWS. 2011. Bexar County Karst 

Invertebrates Recovery Plan. United 

States Fish and Wildlife Service.

Spider, Tooth 

Cave

Leptoneta 

myopica E Arachnid

Lives in caves, which are 

unlikely to be affected by 

trinexapac-ethyl 

applications

USFWS. 1994. Recovery plan for 

endangered karst invertebrates in Travis 

and Williamson counties, Texas. United 

States Fish and Wildlife Service.

Spider, 

Government 

Canyon Bat 

Cave

Neoleptoneta 

microps E Arachnid

Lives in caves, which are 

unlikely to be affected by 

trinexapac-ethyl 

applications

USFWS. 2011. Bexar County Karst 

Invertebrates Recovery Plan. United 

States Fish and Wildlife Service.

Pseudoscorpion, 

Tooth Cave

Tartarocreagris 

texana E Arachnid

Lives in caves, which are 

unlikely to be affected by 

trinexapac-ethyl 

applications

USFWS. 1994. Recovery plan for 

endangered karst invertebrates in Travis 

and Williamson counties, Texas. United 

States Fish and Wildlife Service.

Harvestman, 

Cokendolpher 

Cave

Texella 

cokendolpheri E Arachnid

Lives in caves, which are 

unlikely to be affected by 

trinexapac-ethyl 

applications

USFWS. 2011. Bexar County Karst 

Invertebrates Recovery Plan. United 

States Fish and Wildlife Service.

Harvestman, 

Bee Creek Cave Texella reddelli E Arachnid

Lives in caves, which are 

unlikely to be affected by 

trinexapac-ethyl 

applications

USFWS. 1994. Recovery plan for 

endangered karst invertebrates in Travis 

and Williamson counties, Texas. United 

States Fish and Wildlife Service.

Harvestman, 

Bone Cave Texella reyesi E Arachnid

Lives in caves, which are 

unlikely to be affected by 

trinexapac-ethyl 

applications

USFWS. 1994. Recovery plan for 

endangered karst invertebrates in Travis 

and Williamson counties, Texas. United 

States Fish and Wildlife Service.

Condor, 

California

Gymnogyps 

californianus E Bird

Eats carcasses of dead

mammals, which is not 

one of the affected 

dietary items.

USFWS. 1996. Recovery plan for the 

California condor. United States Fish and 

Wildlife Service.

Stork, Wood

Mycteria 

americana E Bird

Eats fish, which is not 

one of the affected 

dietary items

USFWS. 1986. Wood stork recovery 

plan. United States Fish and Wildlife 

Service.

Tern, Interior 

(population) 

Least

Sterna 

antillarum E Bird

Eats fish, which is not 

one of the affected 

dietary items

USFWS. 1990. Recovery plan for the 

interior popluation of least tern. United 

States Fish and Wildlife Service.

Tern, California 

Least

Sterna 

antillarum 

browni E Bird

Eats fish, which is not 

one of the affected 

dietary items

USFWS. 1980. Revised California least 

tern recovery plan. United States Fish and 

Wildlife Service.

Tern, Roseate

Sterna dougallii 

dougallii E/T Bird

Eats fish, which is not 

one of the affected 

dietary items

USFWS. 1993. Recovery plan for the 

roseate tern. United States Fish and 

Wildlife Service.

Cavesnail, 

Tumbling Creek Antrobia culveri E Gastropod

Lives in caves, which are 

unlikely to be affected by 

trinexapac-ethyl 

applications

USFWS. 2003. Approved recovery plan 

for the tumbling creek cavesnail. United 

States Fish and Wildlife Services.

Snail, Pecos 

Assiminea Assiminea pecos E Gastropod

Aquatic and lives in 

caves

USFWS. 2010. 5-year review summary 

and evaluation. United States Fish and 

Wildlife Service.

Snail, 

Newcomb's

Erinna 

newcombi T Gastropod

Aquatic and not 

terrestrial

USFWS. 2006. Recovery plan for the 

newcomb's snail. United States Fish and 

Wildlife Service.
160

Abalone, Black

Haliotis 

cracherodii E Gastropod

Aquatic marine species -

not found on land FR Notice. 2011. 76 FR 20558 20567

Abalone, White

Haliotis 

sorenseni E Gastropod

Aquatic marine species -

not found on land

USFWS. 2009. Final white abalone 

recovery plan. United States Fish and 

Wildlife Service.

Springsnail, 

Koster's Juturnia kosteri E Gastropod

Aquatic and lives in 

caves

USFWS. 2010. 5-year review summary 

and evaluation. United States Fish and 

Wildlife Service.

Limpet, 

Banbury Springs Lanx sp. E Gastropod

Aquatic species - not 

found on land

USFWS. 1995. Snake river aquatic 

species recovery plan. United States Fish 

and Wildlife Service.

Rocksnail, 

Round Leptoxis ampla T Gastropod

Aquatic species - not 

found on land

USFWS. 2005. Final recovery plan for 

Six Mobile Basin Aquatic Snails. United 

States Fish and Wildlife Services.

Rocksnail, 

interrupted

Leptoxis 

foremani E Gastropod

Aquatic and not 

terrestrial

Federal Register Notice. 2010. Vol 75 

(211): 67511-67550.

Rocksnail, 

Plicate Leptoxis plicata E Gastropod

Aquatic species - not 

found on land

USFWS. 2005. Final recovery plan for 

Six Mobile Basin Aquatic Snails. United 

States Fish and Wildlife Services.

Rocksnail, 

Painted

Leptoxis 

taeniata T Gastropod

Aquatic species - not 

found on land

USFWS. 2005. Final recovery plan for 

Six Mobile Basin Aquatic Snails. United 

States Fish and Wildlife Services.

Pebblesnail, Flat

Lepyrium 

showalteri E Gastropod

Aquatic species - not 

found on land

USFWS. 2005. Final recovery plan for 

Six Mobile Basin Aquatic Snails. United 

States Fish and Wildlife Services.

Snail, Lioplax 

Cylindrical

Lioplax 

cyclostomaformi

s E Gastropod

Aquatic species - not 

found on land

USFWS. 2005. Final recovery plan for

Six Mobile Basin Aquatic Snails. United 

States Fish and Wildlife Services.

Snail, Snake 

River Physa Physa natricina E Gastropod

Aquatic species - not 

found on land

USFWS. 1995. Snake river aquatic 

species recovery plan. United States Fish 

and Wildlife Service.

Hornsnail, rough

Pleurocera 

foremani E Gastropod

Aquatic species - not 

found on land FR Notice. 2010. 75 FR 67512 67550

Springsnail, San 

Bernardino

Pyrgulopsis 

bernardina E Gastropod

Aquatic species - not 

found on land FR Notice. 2012. 77 FR 23060 23092

Springsnail, 

Bruneau Hot

Pyrgulopsis 

bruneauensis E Gastropod

Aquatic species - not 

found on land

USFWS. 2002. Recovery for the bruneau 

hot springsnail. United States Fish and 

Wildlife Service.

Springsnail, 

Roswell

Pyrgulopsis 

roswellensis E Gastropod

Cave and aquatic habitats 

that are unlikely to be 

affected by trinexapacethyl applications

USFWS. 2010. Four bitter lake 

invertebrates 5-year reviews. United 

States Fish and Wildlife Service.

Springsnail, 

Three Forks

Pyrgulopsis 

trivialis E Gastropod

Aquatic species - not 

found on land FR Notice. 2012. 77 FR 23060 23092

Snail, Bliss 

Rapids

Taylorconcha 

serpenticola T Gastropod

Aquatic species - not 

found on land

USFWS. 1995. Snake river aquatic 

species recovery plan. United States Fish 

and Wildlife Service.

Snail, Tulotoma

Tulotoma 

magnifica T Gastropod

Aquatic and not 

terrestrial

USFWS. 2000. Recovery plan for Mobile 

River Basin Aquatic Ecosystem. United 

States Fish and Wildlife Services.

Beetle, Helotes 

Mold

Batrisodes 

venyivi E Insect Lives in a cave.

USFWS. 2011. Bexar County Karst 

Invertebrates Recovery Plan. United 

States Fish and Wildlife Service.
161

Beetle, 

Hungerford's 

Crawling Water

Brychius 

hungerfordi E Insect Aquatic, not terrestrial

USFWS. 2006. Hungerford's crawling 

water beetle recovery plan. United States 

Fish and Wildlife Service.

Beetle, Comal 

Springs Riffle

Heterelmis 

comalensis E Insect Aquatic, not terrestrial

USFWS. 1996. San Marcos and Comal 

Springs and Associated Aquatic 

ecosystems recovery plan. United States 

Fish and Wildlife Service.

Rhadine exilis 

(ncn) Rhadine exilis E Insect

Lives in caves, which are 

unlikely to be affected by 

trinexapac-ethyl 

applications

USFWS. 2011. Bexar County Karst 

Invertebrates Recovery Plan. United 

States Fish and Wildlife Service.

Rhadine 

infernalis (ncn)

Rhadine 

infernalis E Insect Lives in a cave.

USFWS. 2011. Bexar County Karst 

Invertebrates Recovery Plan. United 

States Fish and Wildlife Service.

Beetle, Tooth 

Cave Ground

Rhadine 

persephone E Insect

Lives in caves, which are 

unlikely to be affected by 

trinexapac-ethyl 

applications

USFWS. 1994. Recovery plan for 

endangered karst invertebrates in Travis 

and Williamson counties, Texas. United 

States Fish and Wildlife Service.

Beetle, Comal 

Springs Dryopid

Stygoparnus 

comalensis E Insect Aquatic, not terrestrial

USFWS. 1996. San Marcos and Comal 

Springs and Associated Aquatic 

ecosystems recovery plan. United States 

Fish and Wildlife Service.

Beetle, 

Kretschmarr 

Cave Mold

Texamaurops 

reddelli E Insect

Lives in caves, which are 

unlikely to be affected by 

trinexapac-ethyl 

applications

USFWS. 1994. Recovery plan for 

endangered karst invertebrates in Travis 

and Williamson counties, Texas. United 

States Fish and Wildlife Service.

Table J-3. Listed Species Within Geographical Range of Trinexapac-Ethyl Uses that 

Require Additional Information for Direct Effects Calls

Common Name Scientific Name Taxon STATE NAME

Salamander, 

Reticulated 

flatwoods Ambystoma bishopi Amphibian Florida

Salamander, 

California Tiger

Ambystoma 

californiense Amphibian California

Salamander, 

Frosted Flatwoods Ambystoma cingulatum Amphibian

Alabama, Florida, 

Georgia

Salamander, Santa 

Cruz Long-toed

Ambystoma 

macrodactylum 

croceum Amphibian California

Salamander, 

Sonora Tiger

Ambystoma tigrinum 

stebbinsi Amphibian Arizona

Salamander, Desert 

Slender Batrachoseps aridus Amphibian California

Toad, Arroyo 

Southwestern

Bufo californicus 

(=microscaphus) Amphibian California

Toad, Houston Bufo houstonensis Amphibian Texas
162

Ozark Hellbender

Cryptobranchus 

alleganiensis bishopi Amphibian Arkansas, Missouri

Salamander, San 

Marcos Eurycea nana Amphibian Texas

Salamander, Barton 

Springs Eurycea sosorum Amphibian Texas

Salamander, Red 

Hills Phaeognathus hubrichti Amphibian Alabama

Salamander,

Shenandoah Plethodon shenandoah Amphibian Virginia

Frog, California 

Red-legged Rana aurora draytonii Amphibian California

Frog, Dusky Gopher 

(Mississippi DPS) Rana capito sevosa Amphibian Mississippi

Frog, Chiricahua 

Leopard Rana chiricahuensis Amphibian Arizona

Frog, Mountain 

Yellow-legged Rana muscosa Amphibian California

Spider, Spruce-fir 

Moss Microhexura montivaga Arachnid Virginia

Swiftlet, Mariana 

Gray (=Vanikoro)

Aerodramus 

vanikorensis bartschi Bird Hawaii

Sparrow, Cape 

Sable Seaside

Ammodramus 

maritimus mirabilis Bird Florida

Sparrow, Florida 

Grasshopper

Ammodramus 

savannarum floridanus Bird Florida

Sparrow, San 

Clemente Sage

Amphispiza belli 

clementeae Bird California

Duck, Hawaiian 

(Koloa) Anas wyvilliana Bird Hawaii

Scrub-Jay, Florida

Aphelocoma 

coerulescens Bird Florida

Murrelet, Marbled

Brachyramphus 

marmoratus Bird

California, Oregon, 

Washington

Goose, Hawaiian 

(Nene)

Branta (=Nesochen) 

sandvicensis Bird Hawaii

Hawk, Hawaiian 

(Io) Buteo solitarius Bird Hawaii
163

Woodpecker, Ivorybilled Campephilus principalis Bird Florida, Kentucky

Plover, Western 

Snowy

Charadrius alexandrinus 

nivosus Bird California, Oregon

Plover, Piping Charadrius melodus Bird

Alabama, Colorado, 

Connecticut, 

Florida, Kansas, 

Kentucky, 

Louisiana, 

Michigan, 

Minnesota, 

Mississippi, 

Montana, 

Nebraska, New 

York, North 

Carolina, North 

Dakota, Ohio, 

Oklahoma, South 

Carolina, South 

Dakota, Texas, 

Wyoming

Elepaio, Oahu

Chasiempis 

sandwichensis ibidis Bird Hawaii

Crow, Hawaiian 

('Alala) Corvus hawaiiensis Bird Hawaii

Warbler (=Wood), 

Golden-cheeked Dendroica chrysoparia Bird Texas

Warbler (=Wood), 

Kirtland's Dendroica kirtlandii Bird

Florida, Kentucky, 

Michigan, South 

Carolina, Wisconsin

Flycatcher, 

Southwestern 

Willow

Empidonax traillii 

extimus Bird

Arizona, California, 

Colorado, Nevada, 

New Mexico, Texas, 

Utah

Falcon, Northern 

Aplomado

Falco femoralis 

septentrionalis Bird

Arizona, New 

Mexico, Texas

Coot, Hawaiian 

(=Alae keo keo) Fulica americana alai Bird Hawaii

Moorhen, Hawaiian 

Common

Gallinula chloropus 

sandvicensis Bird Hawaii
164

Crane, Whooping Grus americana Bird

Colorado, Florida, 

Kansas, Montana, 

Nebraska, North 

Dakota, Oklahoma, 

South Dakota, 

Texas, Wyoming

Crane, Mississippi 

Sandhill Grus canadensis pulla Bird Mississippi, Texas

Nukupu`u 

(honeycreeper) Hemignathus lucidus Bird Hawaii

'Akia Pola'au 

(Hemignathus 

munroi) Hemignathus munroi Bird Hawaii

'Akia Loa, Kauai 

(Hemignathus 

procerus) Hemignathus procerus Bird Hawaii

Stilt, Hawaiian 

(=Ae'o)

Himantopus mexicanus 

knudseni Bird Hawaii

Palila Loxioides bailleui Bird Hawaii

Akekee Loxops caeruleirostris Bird Hawaii

'Akepa, Hawaii

Loxops coccineus 

coccineus Bird Hawaii

'Akepa, Maui

Loxops coccineus 

ochraceus Bird Hawaii

Po'ouli

Melamprosops 

phaeosoma Bird Hawaii

'O'o, Kauai (='A'a) Moho braccatus Bird Hawaii

Thrush, Large Kauai Myadestes myadestinus Bird Hawaii

Thrush, Small Kauai 

(Puaiohi) Myadestes palmeri Bird Hawaii

Curlew, Eskimo Numenius borealis Bird

Nebraska, 

Oklahoma, South 

Dakota

Kauai creeper Oreomystis bairdi Bird Hawaii

Creeper, Hawaii Oreomystis mana Bird Hawaii

Honeycreeper, 

Crested 

('Akohekohe) Palmeria dolei Bird Hawaii
165

Creeper, Oahu 

(Alauwahio) Paroreomyza maculata Bird Hawaii

Albatross, ShorttailedPhoebastria 

(=Diomedea) albatrus Bird

California, Oregon, 

Washington

Woodpecker, Redcockaded Picoides borealis Bird

Alabama, Arkansas, 

Florida, Georgia, 

Kentucky, 

Louisiana, 

Mississippi, North 

Carolina, South 

Carolina, 

Tennessee, Texas

Gnatcatcher, 

Coastal California

Polioptila californica 

californica Bird California

Caracara,

Audubon's Crested

Polyborus plancus 

audubonii Bird Florida

Parrotbill, Maui

Pseudonestor 

xanthophrys Bird Hawaii

'O'u 

(Honeycreeper) Psittirostra psittacea Bird Hawaii

Petrel, Hawaiian 

Dark-rumped

Pterodroma 

phaeopygia 

sandwichensis Bird Hawaii

Shearwater, 

Newell's 

Townsend's

Puffinus auricularis 

newelli Bird Hawaii

Rail, California 

Clapper

Rallus longirostris 

obsoletus Bird California

Rail, Yuma Clapper

Rallus longirostris 

yumanensis Bird Arizona, California

Kite, Everglades 

Snail

Rostrhamus sociabilis 

plumbeus Bird Florida

Owl, Northern 

Spotted

Strix occidentalis 

caurina Bird

California, Oregon, 

Washington

Owl, Mexican 

Spotted Strix occidentalis lucida Bird

Arizona, Colorado, 

New Mexico, Texas, 

Utah

Prairie-chicken, 

Attwater's Greater

Tympanuchus cupido 

attwateri Bird Texas
166

Warbler, 

Bachman's Vermivora bachmanii Bird Florida, Kentucky

Vireo, Black-capped Vireo atricapilla Bird Oklahoma, Texas

Vireo, Least Bell's Vireo bellii pusillus Bird California

Cypress, Santa Cruz Cupressus abramsiana Conf/cycds California

Cypress, Gowen

Cupressus goveniana 

ssp. goveniana Conf/cycds California

Torreya, Florida Torreya taxifolia Conf/cycds Florida, Georgia

Sand-verbena, 

Large-fruited Abronia macrocarpa Dicot Texas

Ko'oloa'ula 

(Abutilon menziesii) Abutilon menziesii Dicot Hawaii

Abutilon 

sandwicense (ncn) Abutilon sandwicense Dicot Hawaii

Liliwai (Acaena 

exigua) Acaena exigua Dicot Hawaii

Achyranthes mutica 

(ncn) Achyranthes mutica Dicot Hawaii

Achyranthes 

splendens var. 

rotundata (ncn)

Achyranthes splendens 

var. rotundata Dicot Hawaii

Joint-vetch, 

Sensitive

Aeschynomene 

virginica Dicot

Maryland, New 

Jersey, North 

Carolina, Virginia

Gerardia, Sandplain Agalinis acuta Dicot New York

Mahoe (Alectryon 

macrococcus) Alectryon macrococcus Dicot Hawaii

Kuawawaenohu 

(Alsinidendron 

lychnoides)

Alsinidendron 

lychnoides Dicot Hawaii

Alsinidendron 

obovatum (ncn)

Alsinidendron 

obovatum Dicot Hawaii

Alsinidendron 

trinerve (ncn) Alsinidendron trinerve Dicot Hawaii

Alsinidendron 

viscosum (ncn) Alsinidendron viscosum Dicot Hawaii

Amaranth, 

Seabeach Amaranthus pumilus Dicot

New York, North 

Carolina, South 

Carolina
167

Ambrosia, South 

Texas

Ambrosia 

cheiranthifolia Dicot Texas

Ambrosia, San 

Diego Ambrosia pumila Dicot California

Lead-plant, 

Crenulate Amorpha crenulata Dicot Florida

Amphianthus, Little Amphianthus pusillus Dicot

Alabama, Georgia, 

South Carolina

Fiddleneck, Largeflowered Amsinckia grandiflora Dicot California

Cactus, Tobusch 

Fishhook

Ancistrocactus 

tobuschii Dicot Texas

Potato-bean, 

Price's Apios priceana Dicot

Alabama, Kentucky, 

Mississippi, 

Tennessee

Rock-cress, 

McDonald's Arabis mcdonaldiana Dicot California, Oregon

Rock-cress, Shale 

Barren Arabis serotina Dicot

Virginia, West 

Virginia

Bearclaw poppy, 

Dwarf Arctomecon humilis Dicot Utah

Manzanita, Morro

Arctostaphylos 

morroensis Dicot California

Sandwort, Marsh Arenaria paludicola Dicot

California, 

Washington

Silversword, Ka'u 

(Argyroxiphium 

kauense) Argyroxiphium kauense Dicot Hawaii

Silversword, 

Haleakala 

('Ahinahina)

Argyroxiphium 

sandwicense ssp. 

macrocephalum Dicot Hawaii

Silversword, Mauna 

Kea ('Ahinahina)

Argyroxiphium 

sandwicense ssp. 

sandwicense Dicot Hawaii

Milkweed, Mead's Asclepias meadii Dicot Kansas, Missouri

Pawpaw, Fourpetal Asimina tetramera Dicot Florida

Milk-vetch,

Shivwits

Astragalus 

ampullarioides Dicot Utah

Milk-vetch, Clara 

Hunt's Astragalus clarianus Dicot California
168

Milk-vetch, Deseret Astragalus desereticus Dicot Utah

Milk-vetch, 

Holmgren

Astragalus 

holmgreniorum Dicot Arizona, Utah

Milk-vetch, Mancos Astragalus humillimus Dicot

Colorado, New 

Mexico

Milk-vetch, 

Coachella Valley

Astragalus lentiginosus 

var. coachellae Dicot California

Milk-vetch, 

Pierson's

Astragalus magdalenae 

var. peirsonii Dicot California

Milk-vetch, 

Heliotrope Astragalus montii Dicot Utah

Milk-vetch, Coastal 

Dunes Astragalus tener var. titi Dicot California

Milk-vetch, Tripleribbed Astragalus tricarinatus Dicot California

Cactus, Star Astrophytum asterias Dicot Texas

Crownscale, San 

Jacinto Valley

Atriplex coronata var. 

notatior Dicot California

Ayenia, Texas Ayenia limitaris Dicot Texas

Barberry, Nevin's Berberis nevinii Dicot California

Birch, Virginia 

Round-leaf Betula uber Dicot Virginia

ko`oko`olau Bidens amplectens Dicot Hawaii

ko`oko`olau

Bidens campylotheca 

ssp. Pentamera Dicot Hawaii

ko`oko`olau

Bidens campylotheca 

ssp. Waihoiensis Dicot Hawaii

ko`oko`olau Bidens conjuncta Dicot Hawaii

Ko'oko'olau (Bidens 

micrantha ssp. 

kalealaha)

Bidens micrantha ssp. 

kalealaha Dicot Hawaii

Stickyseed, Baker's Blennosperma bakeri Dicot California

Aster, Decurrent 

False Boltonia decurrens Dicot Illinois, Missouri
169

Bonamia, Florida Bonamia grandiflora Dicot Florida

Bonamia menziesii 

(ncn) Bonamia menziesii Dicot Hawaii

'Olulu (Brighamia 

insignis) Brighamia insignis Dicot Hawaii

Pua'ala (Brighamia 

rockii) Brighamia rockii Dicot Hawaii

Boxwood, Vahl's Buxus vahlii Dicot Virgin Islands

Uhiuhi (Caesalpinia 

kavaiensis) Caesalpinia kavaiense Dicot Hawaii

Pussypaws, 

Mariposa

Calyptridium 

pulchellum Dicot California

Evening-primrose, 

San Benito Camissonia benitensis Dicot California

Bellflower, 

Brooksville Campanula robinsiae Dicot Florida

awikiwiki Canavalia napaliensis Dicot Hawaii

Bittercress, Smallanthered Cardamine micranthera DicotNorth Carolina, 

Virginia

Paintbrush, Tiburon

Castilleja affinis ssp. 

neglecta Dicot California

Clover, Fleshy Owl's

Castilleja campestris 

ssp. succulenta Dicot California

Paintbrush, Golden Castilleja levisecta Dicot

Oregon, 

Washington

Catesbaea 

Melanocarpa (ncn) Catesbaea melanocarpa Dicot Virgin Islands

Jewelflower, 

California Caulanthus californicus Dicot California

Ceanothus, Vail 

Lake Ceanothus ophiochilus Dicot California

'Awiwi (Centaurium 

sebaeoides) Centaurium sebaeoides Dicot Hawaii

'Akoko 

(Chamaesyce 

celastroides var. 

kaenana)

Chamaesyce 

celastroides var. 

kaenana Dicot Hawaii
170

Spurge, Deltoid

Chamaesyce deltoidea 

ssp. deltoidea Dicot Florida

'Akoko 

(Chamaesyce 

deppeana) Chamaesyce deppeana Dicot Hawaii

'akoko Chamaesyce eleanoriae Dicot Hawaii

Spurge, Garber's Chamaesyce garberi Dicot Florida

Chamaesyce 

Halemanui (ncn) Chamaesyce halemanui Dicot Hawaii

'Akoko 

(Chamaesyce 

herbstii) Chamaesyce herbstii Dicot Hawaii

Spurge, Hoover's Chamaesyce hooveri Dicot California

'Akoko 

(Chamaesyce 

kuwaleana) Chamaesyce kuwaleana Dicot Hawaii

Akoko

Chamaesyce remyi var. 

kauaiensis Dicot Hawaii

'Akoko 

(Chamaesyce 

rockii) Chamaesyce rockii Dicot Hawaii

'Akoko 

(Chamaesyce 

skottsbergii var. 

skottsbe

Chamaesyce 

skottsbergii var. 

kalaeloana Dicot Hawaii

Papala Charpentiera densiflora Dicot Hawaii

Fringe Tree, Pygmy Chionanthus pygmaeus Dicot Florida

Spineflower, 

Monterey

Chorizanthe pungens 

var. pungens Dicot California

Spineflower, 

Robust

Chorizanthe robusta va 

r. robusta Dicot California

Spineflower, 

Sonoma Chorizanthe valida Dicot California

Aster, Florida 

Golden Chrysopsis floridana Dicot Florida
171

Thistle, Chorro 

creek Bog

Cirsium fontinale var. 

obispoense Dicot California

Thistle, Suisun

Cirsium hydrophilum 

var. hydrophilum Dicot California

Thistle, La Graciosa Cirsium loncholepis Dicot California

Thistle, Pitcher's Cirsium pitcheri Dicot

Illinois, Indiana, 

Michigan, 

Wisconsin

Clarkia, Vine Hill Clarkia imbricata Dicot California

Clarkia, Pismo

Clarkia speciosa ssp. 

immaculata Dicot California

Clarkia, Springville Clarkia springvillensis Dicot California

Leather-flower, 

Morefield's Clematis morefieldii Dicot Alabama

Leather-flower, 

Alabama Clematis socialis Dicot Alabama, Georgia

'Oha Wai 

(Clermontia 

drepanomorpha)

Clermontia 

drepanomorpha Dicot Hawaii

'Oha Wai 

(Clermontia 

lindseyana) Clermontia lindseyana Dicot Hawaii

'Oha Wai 

(Clermontia 

oblongifolia ssp. 

mauiensis)

Clermontia oblongifolia 

ssp. mauiensis Dicot Hawaii

'Oha Wai 

(Clermontia 

peleana) Clermontia peleana Dicot Hawaii

'Oha Wai 

(Clermontia 

pyrularia) Clermontia pyrularia Dicot Hawaii

'Oha Wai 

(Clermontia 

samuelii) Clermontia samuelii Dicot Hawaii

Wings, Pigeon Clitoria fragrans Dicot Florida

Kauila (Colubrina 

oppositifolia) Colubrina oppositifolia Dicot Hawaii

Rosemary, Shortleaved Conradina brevifolia Dicot Florida
172

Rosemary, 

Cumberland Conradina verticillata Dicot Tennessee

Bird's-beak, salt 

marsh

Cordylanthus maritimus 

ssp. maritimus Dicot California

Bird's-beak, Soft

Cordylanthus mollis ssp. 

mollis Dicot California

Bird's-beak, 

Palmate-bracted Cordylanthus palmatus Dicot California

Bird's-beak, 

Pennell's

Cordylanthus tenuis 

ssp. capillaris Dicot California

Cactus, Cochise 

Pincushion

Coryphantha 

robbinsorum Dicot Arizona

Cactus, Lee 

Pincushion

Coryphantha sneedii 

var. leei Dicot New Mexico

Cactus, Sneed 

Pincushion

Coryphantha sneedii 

var. sneedii Dicot New Mexico, Texas

Harebells, Avon 

Park Crotalaria avonensis Dicot Florida

Gourd, 

Okeechobee

Cucurbita 

okeechobeensis ssp. 

okeechobeensis Dicot Florida

Haha (Cyanea 

Crispa) (=Rollandia 

crispa)

Cyanea (=Rollandia) 

crispa Dicot Hawaii

Haha (Cyanea 

acuminata) Cyanea acuminata Dicot Hawaii

Haha (Cyanea 

asarifolia) Cyanea asarifolia Dicot Hawaii

haha (Cyanea 

asplenifolia) Cyanea asplenifolia Dicot Hawaii

Haha Cyanea calycina Dicot Hawaii

Haha (Cyanea 

copelandii ssp. 

copelandii)

Cyanea copelandii ssp. 

copelandii Dicot Hawaii

Haha (Cyanea 

copelandii ssp. 

haleakalaensis)

Cyanea copelandii ssp. 

haleakalaensis Dicot Hawaii

Haha Cyanea dolichopoda Dicot Hawaii
173

haha (Cyanea 

duvalliorum) Cyanea duvalliorum Dicot Hawaii

haha Cyanea eleeleensis Dicot Hawaii

Haha (Cyanea 

glabra) Cyanea glabra Dicot Hawaii

Haha (Cyanea 

grimesiana ssp. 

grimesiana)

Cyanea grimesiana ssp. 

grimesiana Dicot Hawaii

Haha (Cyanea 

grimesiana ssp. 

obatae)

Cyanea grimesiana ssp. 

obatae Dicot Hawaii

Haha (Cyanea 

hamatiflora ssp. 

carlsonii)

Cyanea hamatiflora ssp. 

Carlsonii Dicot Hawaii

Haha (Cyanea 

hamatiflora ssp. 

hamatiflora)

Cyanea hamatiflora ssp. 

hamatiflora Dicot Hawaii

nui haha (Cyanea 

horrida) Cyanea horrida Dicot Hawaii

Haha (Cyanea 

humboldtiana) Cyanea humboldtiana Dicot Hawaii

(ncn) Cyanea kolekoleensis Dicot Hawaii

Haha (Cyanea 

koolauensis) Cyanea koolauensis Dicot Hawaii

Haha Cyanea kuhihewa Dicot Hawaii

haha (Cyanea 

kunthiana) Cyanea kunthiana Dicot Hawaii

Haha Cyanea lanceolata Dicot Hawaii

Haha (Cyanea 

lobata) Cyanea lobata Dicot Hawaii

Haha (Cyanea 

longiflora) Cyanea longiflora Dicot Hawaii

haha (Cyanea 

magnicalyx) Cyanea magnicalyx Dicot Hawaii

haha (Cyanea 

maritae) Cyanea maritae Dicot Hawaii

haha (Cyanea 

mauiensis) Cyanea mauiensis Dicot Hawaii

Haha (Cyanea 

mceldowneyi) Cyanea mceldowneyi Dicot Hawaii
174

haha (Cyanea 

obtusa) Cyanea obtusa Dicot Hawaii

Haha (Cyanea 

pinnatifida) Cyanea pinnatifida Dicot Hawaii

Haha (Cyanea 

platyphylla) Cyanea platyphylla Dicot Hawaii

haha Cyanea purpurellifolia Dicot Hawaii

Haha (Cyanea 

recta) Cyanea recta Dicot Hawaii

Haha (Cyanea 

remyi) Cyanea remyi Dicot Hawaii

Haha (Cyanea 

shipmanii) Cyanea shipmannii Dicot Hawaii

Haha (Cyanea 

stictophylla) Cyanea stictophylla Dicot Hawaii

Haha (Cyanea StJohnii) (=Rollandia 

St-Johnii) Cyanea st-johnii Dicot Hawaii

Haha (Cyanea 

superba) Cyanea superba Dicot Hawaii

Haha (Cyanea 

truncata) Cyanea truncata Dicot Hawaii

Cyanea undulata 

(ncn) Cyanea undulata Dicot Hawaii

Cycladenia, Jones

Cycladenia jonesii 

(=humilis) Dicot Arizona

Ha'Iwale (Cyrtandra 

crenata) Cyrtandra crenata Dicot Hawaii

Mapele (Cyrtandra 

cyaneoides) Cyrtandra cyaneoides Dicot Hawaii

Ha'Iwale (Cyrtandra 

dentata) Cyrtandra dentata Dicot Hawaii

haiwale Cyrtandra ferripilosa Dicot Hawaii

ha`iwale (Cyrtandra 

filipes) Cyrtandra filipes Dicot Hawaii

Ha'Iwale (Cyrtandra 

giffardii) Cyrtandra giffardii Dicot Hawaii

haiwale Cyrtandra gracilis Dicot Hawaii

ha`iwale Cyrtandra kaulantha Dicot Hawaii
175

Ha'Iwale (Cyrtandra 

limahuliensis) Cyrtandra limahuliensis Dicot Hawaii

Ha'Iwale (Cyrtandra 

munroi) Cyrtandra munroi Dicot Hawaii

Ha'iwale (Cyrtandra 

oenobarba) Cyrtandra oenobarba Dicot Hawaii

ha`iwale (Cyrtandra 

oxybapha) Cyrtandra oxybapha Dicot Hawaii

haiwale Cyrtandra paliku Dicot Hawaii

Ha'Iwale (Cyrtandra 

polyantha) Cyrtandra polyantha Dicot Hawaii

ha`iwale Cyrtandra sessilis Dicot Hawaii

Ha'Iwale (Cyrtandra 

subumbellata) Cyrtandra subumbellata Dicot Hawaii

Ha'Iwale (Cyrtandra 

tintinnabula) Cyrtandra tintinnabula Dicot Hawaii

Ha'Iwale (Cyrtandra 

viridiflora) Cyrtandra viridiflora Dicot Hawaii

haiwale Cyrtandra waiolani Dicot Hawaii

Clover, Leafy Prairie Dalea foliosa Dicot

Alabama, 

Tennessee

Delissea 

rhytodisperma 

(ncn) Delissea rhytidosperma Dicot Hawaii

'Oha (Delissea 

rivularis) Delissea rivularis Dicot Hawaii

'Oha (Delissea 

subcordata) Delissea subcordata Dicot Hawaii

'Oha (Delissea 

undulata) Delissea undulata Dicot Hawaii

Larkspur, Baker's Delphinium bakeri Dicot California

Larkspur, Yellow Delphinium luteum Dicot California

Mint, Longspurred

Dicerandra 

cornutissima Dicot Florida

Mint, Scrub Dicerandra frutescens Dicot Florida

Mint, Lakela's Dicerandra immaculata Dicot Florida

Spineflower, 

Slender-horned

Dodecahema 

leptoceras Dicot California

Na'ena'e (Dubautia 

herbstobatae) Dubautia herbstobatae Dicot Hawaii
176

na`ena`e

Dubautia imbricata 

imbricata Dicot Hawaii

Naenae Dubautia kalalauensis Dicot Hawaii

Naenae Dubautia kenwoodii Dicot Hawaii

Dubautia latifolia 

(ncn) Dubautia latifolia Dicot Hawaii

Dubautia 

pauciflorula (ncn) Dubautia pauciflorula Dicot Hawaii

na`ena`e

Dubautia plantaginea 

magnifolia Dicot Hawaii

Na'ena'e (Dubautia 

plantaginea ssp. 

humilis)

Dubautia plantaginea 

ssp. humilis Dicot Hawaii

Na`ena`e Dubautia waialealae Dicot Hawaii

Coneflower, 

Smooth Echinacea laevigata Dicot

South Carolina, 

Virginia

Cactus, Nichol's 

Turk's Head

Echinocactus 

horizonthalonius var. 

nicholii Dicot Arizona

Cactus, Kuenzler 

Hedgehog

Echinocereus fendleri 

var. kuenzleri Dicot New Mexico

Cactus, Black Lace

Echinocereus 

reichenbachii var. 

albertii Dicot Texas

Cactus, Arizona 

Hedgehog

Echinocereus 

triglochidiatus var. 

arizonicus Dicot Arizona

Cactus, Lloyd's 

Mariposa

Echinomastus 

mariposensis Dicot Texas

Poolfish, Pahrump 

(= Pahrump 

Killifish) Empetrichthys latos Dicot Nevada

Mallow, Kern Eremalche kernensis Dicot California

Woolly-star, Santa 

Ana River

Eriastrum densifolium 

ssp. sanctorum Dicot California
177

Daisy, Willamette

Erigeron decumbens 

var. decumbens Dicot Oregon

Daisy, Parish's Erigeron parishii Dicot California

Fleabane, Zuni Erigeron rhizomatus Dicot

Arizona, New 

Mexico

Mountainbalm, 

Indian Knob Eriodictyon altissimum Dicot California

Wild-buckwheat, 

Gypsum

Eriogonum 

gypsophilum Dicot New Mexico

Buckwheat, 

Southern Mountain 

Wild

Eriogonum kennedyi 

var. austromontanum Dicot California

Buckwheat, Scrub

Eriogonum longifolium 

var. gnaphalifolium Dicot Florida

Wild-buckwheat, 

Clay-loving

Eriogonum 

pelinophilum Dicot Colorado

Sunflower, San 

Mateo Woolly Eriophyllum latilobum Dicot California

Button-celery, San 

Diego

Eryngium aristulatum 

var. parishii Dicot California

Coyote-thistle, Loch 

Lomond Eryngium constancei Dicot California

Wallflower, 

Menzie's Erysimum menziesii Dicot California

Nioi (Eugenia 

koolauensis) Eugenia koolauensis Dicot Hawaii

'Akoko (Euphorbia 

haeleeleana) Euphorbia haeleeleana Dicot Hawaii

Spurge, Telephus Euphorbia telephioides Dicot Florida

Heau (Exocarpos 

luteolus) Exocarpos luteolus Dicot Hawaii

Mehamehame 

(Flueggea 

neowawraea) Flueggea neowawraea Dicot Hawaii

Frankenia, 

Johnston's Frankenia johnstonii Dicot Texas

Milkpea, Small's Galactia smallii Dicot Florida
178

Na'u (Gardenia 

brighamii) Gardenia brighamii Dicot Hawaii

Nanu (Gardenia 

mannii) Gardenia mannii Dicot Hawaii

Butterfly Plant, 

Colorado

Gaura neomexicana

var. coloradensis Dicot Colorado, Nebraska

Fruit, Earth 

(=geocarpon) Geocarpon minimum Dicot Missouri, Texas

Geranium, 

Hawaiian Redflowered Geranium arboreum Dicot Hawaii

nohoanu 

(Geranium 

hanaense) Geranium hanaense Dicot Hawaii

nohoanu 

(Geranium 

hillebrandii) Geranium hillebrandii Dicot Hawaii

nohoanu Geranium kauaiense Dicot Hawaii

Nohoanu 

(Geranium 

multiflorum) Geranium multiflorum Dicot Hawaii

Avens, Spreading Geum radiatum Dicot North Carolina

Gilia, Monterey

Gilia tenuiflora ssp. 

arenaria Dicot California

Gouania 

hillebrandii (ncn) Gouania hillebrandii Dicot Hawaii

Gouania meyenii 

(ncn) Gouania meyenii Dicot Hawaii

Gouania vitifolia 

(ncn) Gouania vitifolia Dicot Hawaii

Haplostachys 

Haplostachya (ncn)

Haplostachys 

haplostachya Dicot Hawaii

'Awiwi (Hedyotis 

cookiana) Hedyotis cookiana Dicot Hawaii

Kio'Ele (Hedyotis 

coriacea) Hedyotis coriacea Dicot Hawaii

Hedyotis degeneri 

(ncn) Hedyotis degeneri Dicot Hawaii

Pilo (Hedyotis 

mannii) Hedyotis mannii Dicot Hawaii

Hedyotis parvula 

(ncn) Hedyotis parvula Dicot Hawaii
179

Bluet, Roan 

Mountain

Hedyotis purpurea var. 

montana Dicot North Carolina

Hedyotis St.-Johnii 

(ncn) Hedyotis st.-johnii Dicot Hawaii

Sneezeweed, 

Virginia Helenium virginicum Dicot Missouri, Virginia

Rush-rose, Island Helianthemum greenei Dicot California

Sunflower, Pecos Helianthus paradoxus Dicot New Mexico

Sunflower, 

Schweinitz's Helianthus schweinitzii Dicot

North Carolina, 

South Carolina, 

Virginia

Dwarf-flax, Marin

Hesperolinon 

congestum Dicot California

Hesperomannia 

arborescens (ncn)

Hesperomannia 

arborescens Dicot Hawaii

Hesperomannia 

arbuscula (ncn)

Hesperomannia 

arbuscula Dicot Hawaii

Hesperomannia 

lydgatei (ncn)

Hesperomannia 

lydgatei Dicot Hawaii

Heartleaf, Dwarfflowered Hexastylis naniflora DicotNorth Carolina, 

South Carolina

Hau Kuahiwi 

(Hibiscadelphus 

distans) Hibiscadelphus distans Dicot Hawaii

Hau Kuahiwi 

(Hibiscadelphus 

giffardianus)

Hibiscadelphus 

giffardianus Dicot Hawaii

Hau Kuahiwi 

(Hibiscadelphus 

hualalaiensis)

Hibiscadelphus 

hualalaiensis Dicot Hawaii

Hau Kauhiwi 

(Hibiscadelphus 

woodi) Hibiscadelphus woodii Dicot Hawaii

Ma'o Hau Hele 

(Hibiscus 

brackenridgei) Hibiscus brackenridgei Dicot Hawaii

Hibiscus, Clay's Hibiscus clayi Dicot Hawaii

Koki'o Ke'oke'o 

(Hibiscus waimeae 

ssp. hannerae)

Hibiscus waimeae ssp. 

hannerae Dicot Hawaii
180

Tarplant, Santa 

Cruz Holocarpha macradenia Dicot California

Howellia, Water Howellia aquatilis Dicot

Idaho, Montana, 

Oregon, 

Washington

Dawn-flower, Texas 

Prairie (=Texas 

Bitterweed) Hymenoxys texana Dicot Texas

Hypericum, 

Highlands Scrub Hypericum cumulicola Dicot Florida

Aupaka 

(Isodendrion 

hosakae) Isodendrion hosakae Dicot Hawaii

Aupaka 

(Isodendrion 

laurifolium) Isodendrion laurifolium Dicot Hawaii

Aupaka 

(Isodendrion 

longifolium) Isodendrion longifolium Dicot Hawaii

Wahine Noho Kula 

(Isodendrion 

pyrifolium) Isodendrion pyrifolium Dicot Hawaii

Water-willow, 

Cooley's Justicia cooleyi Dicot Florida

(ncn)

Keysseria (=Lagenifera) 

erici Dicot Hawaii

(ncn)

Keysseria (=Lagenifera) 

helenae Dicot Hawaii

Koki'o (Kokia 

drynarioides) Kokia drynarioides Dicot Hawaii

Koki'o (Kokia 

kauaiensis) Kokia kauaiensis Dicot Hawaii

Kamakahala 

(Labordia 

cyrtandrae) Labordia cyrtandrae Dicot Hawaii

kamakahala Labordia helleri Dicot Hawaii

Kamakahala 

(Labordia lydgatei) Labordia lydgatei Dicot Hawaii

kamakahala Labordia pumila Dicot Hawaii
181

Kamakahala 

(Labordia tinifolia 

var. wahiawaen)

Labordia tinifolia var. 

wahiawaensis Dicot Hawaii

Goldfields, Burke's Lasthenia burkei Dicot California

Goldfields, Contra 

Costa Lasthenia conjugens Dicot California

Layia, Beach Layia carnosa Dicot California

'Anaunau 

(Lepidium 

arbuscula) Lepidium arbuscula Dicot Hawaii

Ridge-cress 

(=Pepper-cress), 

Barneby Lepidium barnebyanum Dicot Utah

Peppergrass, Slick 

Spot Lepidium papilliferum Dicot Idaho

Clover, Prairie Bush Lespedeza leptostachya Dicot

Illinois, Iowa, 

Minnesota

Bladderpod, Dudley 

Bluffs Lesquerella congesta Dicot Colorado

Bladderpod, 

Missouri Lesquerella filiformis Dicot Arkansas, Missouri

Bladderpod, Lyrate Lesquerella lyrata Dicot Alabama

Bladderpod, Zapata

Lesquerella 

thamnophila Dicot Texas

Blazing Star, 

Heller's Liatris helleri Dicot North Carolina

Blazing Star, Scrub Liatris ohlingerae Dicot Florida

Umbel, Huachuca 

Water

Lilaeopsis schaffneriana 

var. recurva Dicot Arizona

Meadowfoam, 

Large-flowered 

Woolly

Limnanthes floccosa 

ssp. Grandiflora Dicot Oregon

Meadowfoam, 

Sebastopol Limnanthes vinculans Dicot California

Pondberry Lindera melissifolia Dicot

Alabama, Georgia, 

Mississippi, 

Missouri, South 

Carolina

Nehe (Lipochaeta 

fauriei) Lipochaeta fauriei Dicot Hawaii
182

Nehe (Lipochaeta 

kamolensis) Lipochaeta kamolensis Dicot Hawaii

Nehe (Lipochaeta 

lobata var. 

leptophylla)

Lipochaeta lobata var. 

leptophylla Dicot Hawaii

Nehe (Lipochaeta 

micrantha) Lipochaeta micrantha Dicot Hawaii

Nehe (Lipochaeta 

tenuifolia) Lipochaeta tenuifolia Dicot Hawaii

Lipochaeta venosa 

(ncn) Lipochaeta venosa Dicot Hawaii

Nehe (Lipochaeta 

waimeaensis)

Lipochaeta 

waimeaensis Dicot Hawaii

'Oha (Lobelia 

gaudichaudii 

koolauensis)

Lobelia gaudichaudii 

ssp. koolauensis Dicot Hawaii

Lobelia 

monostachya (ncn) Lobelia monostachya Dicot Hawaii

Lobelia niihauensis 

(ncn) Lobelia niihauensis Dicot Hawaii

Lobelia oahuensis 

(ncn) Lobelia oahuensis Dicot Hawaii

Lomatium, 

Bradshaw's Lomatium bradshawii Dicot

Oregon, 

Washington

Lomatium, Cook's Lomatium cookii Dicot Oregon

Lupine, Scrub Lupinus aridorum Dicot Florida

Lupine, Nipomo 

Mesa Lupinus nipomensis Dicot California

Lupine, Kincaid's

Lupinus sulphureus 

(=oreganus) ssp. 

kincaidii (=var. kincaidii) Dicot Oregon

Lupine, Clover Lupinus tidestromii Dicot California

Loosestrife, RoughleavedLysimachia 

asperulaefolia Dicot South Carolina

lehua makanoe Lysimachia daphnoides Dicot Hawaii

Lysimachia filifolia 

(ncn) Lysimachia filifolia Dicot Hawaii

(ncn) Lysimachia iniki Dicot Hawaii

Lysimachia lydgatei 

(ncn) Lysimachia lydgatei Dicot Hawaii
183

(ncn) Lysimachia pendens Dicot Hawaii

(ncn) Lysimachia scopulensis Dicot Hawaii

(ncn) Lysimachia venosa Dicot Hawaii

Birds-in-a-nest, 

White Macbridea alba Dicot Florida

Manioc, Walker's Manihot walkerae Dicot Texas

Barbara Buttons, 

Mohr's Marshallia mohrii Dicot Alabama, Georgia

Alani (Melicope 

adscendens) Melicope adscendens Dicot Hawaii

Alani (Melicope 

balloui) Melicope balloui Dicot Hawaii

alani

Melicope

christophersenii Dicot Hawaii

alani Melicope degeneri Dicot Hawaii

Alani (Melicope 

haupuensis) Melicope haupuensis Dicot Hawaii

alani Melicope hiiakae Dicot Hawaii

Alani (Melicope 

knudsenii) Melicope knudsenii Dicot Hawaii

Alani (Melicope 

lydgatei) Melicope lydgatei Dicot Hawaii

alani Melicope makahae Dicot Hawaii

Alani (Melicope 

mucronulata) Melicope mucronulata Dicot Hawaii

Alani (Melicope 

ovalis) Melicope ovalis Dicot Hawaii

Alani (Melicope 

pallida) Melicope pallida Dicot Hawaii

alani Melicope paniculata Dicot Hawaii

alani Melicope puberula Dicot Hawaii

Alani (Melicope 

quadrangularis)

Melicope 

quadrangularis Dicot Hawaii

Alani (Melicope 

saint-johnii) Melicope saint-johnii Dicot Hawaii

Alani (Melicope 

zahlbruckneri) Melicope zahlbruckneri Dicot Hawaii

Monkey-flower, 

Michigan

Mimulus glabratus var. 

michiganensis Dicot Michigan
184

Four-o'clock, 

Macfarlane's Mirabilis macfarlanei Dicot Idaho, Oregon

Woolly-threads, 

San Joaquin

Monolopia 

(=Lembertia) congdonii Dicot California

sea bean

Mucuna sloanei var. 

persericea Dicot Hawaii

Munroidendron 

racemosum (ncn)

Munroidendron 

racemosum Dicot Hawaii

Kolea (Myrsine 

juddii) Myrsine juddii Dicot Hawaii

Kolea Myrsine knudsenii Dicot Hawaii

Kolea (Myrsine 

linearifolia) Myrsine linearifolia Dicot Hawaii

kolea Myrsine mezii Dicot Hawaii

kolea Myrsine vaccinioides Dicot Hawaii

Navarretia, 

Spreading Navarretia fossalis Dicot California

Navarretia, Fewflowered

Navarretia 

leucocephala ssp. 

Pauciflora Dicot California

Navarretia, Manyflowered

Navarretia

leucocephala ssp. 

plieantha Dicot California

Neraudia angulata 

(ncn) Neraudia angulata Dicot Hawaii

Neraudia ovata 

(ncn) Neraudia ovata Dicot Hawaii

Neraudia sericea 

(ncn) Neraudia sericea Dicot Hawaii

Niterwort, 

Amargosa Nitrophila mohavensis Dicot Nevada

'Aiea 

(Nothocestrum 

breviflorum)

Nothocestrum 

breviflorum Dicot Hawaii

'Aiea 

(Nothocestrum 

peltatum) Nothocestrum peltatum Dicot Hawaii

Kulu'I 

(Nototrichium 

humile) Nototrichium humile Dicot Hawaii
185

Holei (Ochrosia 

kilaueaensis) Ochrosia kilaueaensis Dicot Hawaii

Evening-primrose, 

Antioch Dunes

Oenothera deltoides 

ssp. howellii Dicot California

Cactus, Bakersfield Opuntia treleasei Dicot California

Grass, Hairy Orcutt Orcuttia pilosa Dicot California

Grass, Slender 

Orcutt Orcuttia tenuis Dicot California

Grass, Sacramento 

Orcutt Orcuttia viscida Dicot California

Dropwort, Canby's Oxypolis canbyi Dicot

Georgia, South 

Carolina

Locoweed, Fassett's

Oxytropis campestris 

var. chartacea Dicot Wisconsin

Whitlow-wort, 

Papery Paronychia chartacea Dicot Florida

Lousewort, Furbish Pedicularis furbishiae Dicot Maine

Cactus, Siler 

Pincushion

Pediocactus 

(=Echinocactus,=Utahia) 

sileri Dicot Arizona, Utah

Cactus, Knowlton Pediocactus knowltonii Dicot New Mexico

Cactus, Peebles 

Navajo

Pediocactus 

peeblesianus 

peeblesianus Dicot Arizona

Penstemon, 

Blowout Penstemon haydenii Dicot

Nebraska, 

Wyoming

alaala wai nui Peperomia subpetiolata Dicot Hawaii

Makou 

(Peucedanum 

sandwicense)

Peucedanum 

sandwicense Dicot Hawaii

Phacelia, Clay Phacelia argillacea Dicot Utah

Phacelia, North 

Park Phacelia formosula Dicot Colorado

DeBeque phacelia Phacelia submutica Dicot Colorado

Phlox, Texas 

Trailing

Phlox nivalis ssp. 

texensis Dicot Texas
186

ncn (Phyllostegia 

bracteata) Phyllostegia bracteata Dicot Hawaii

ncn (Phyllostegia 

haliakalae) Phyllostegia haliakalae Dicot Hawaii

Phyllostegia hirsuta 

(ncn) Phyllostegia hirsuta Dicot Hawaii

(ncn) Phyllostegia hispida Dicot Hawaii

Phyllostegia 

kaalaensis (ncn) Phyllostegia kaalaensis Dicot Hawaii

Phyllostegia 

knudsenii (ncn) Phyllostegia knudsenii Dicot Hawaii

Phyllostegia mannii 

(ncn) Phyllostegia mannii Dicot Hawaii

Phyllostegia mollis 

(ncn) Phyllostegia mollis Dicot Hawaii

Phyllostegia 

parviflora (ncn) Phyllostegia parviflora Dicot Hawaii

ncn (Phyllostegia 

pilosa) Phyllostegia pilosa Dicot Hawaii

Kiponapona 

(Phyllostegia 

racemosa) Phyllostegia racemosa Dicot Hawaii

(ncn) Phyllostegia renovans Dicot Hawaii

Phyllostegia 

velutina (ncn) Phyllostegia velutina Dicot Hawaii

Phyllostegia 

waimeae (ncn) Phyllostegia waimeae Dicot Hawaii

Phyllostegia 

warshaueri (ncn) Phyllostegia warshaueri Dicot Hawaii

Phyllostegia 

wawrana (ncn) Phyllostegia wawrana Dicot Hawaii

Twinpod, Dudley 

Bluffs Physaria obcordata Dicot Colorado

Butterwort, 

Godfrey's Pinguicula ionantha Dicot Florida

ho'awa Pittosporum napaliense Dicot Hawaii

Popcornflower, 

Rough Plagiobothrys hirtus Dicot Oregon

Allocarya, Calistoga Plagiobothrys strictus Dicot California
187

Laukahi Kuahiwi 

(Plantago 

hawaiensis) Plantago hawaiensis Dicot Hawaii

Laukahi Kuahiwi 

(Plantago princeps) Plantago princeps Dicot Hawaii

(ncn)

Platydesma cornuta 

var. cornuta Dicot Hawaii

(ncn)

Platydesma cornuta 

var. decurrens Dicot Hawaii

pilo kea lau li`i Platydesma rostrata Dicot Hawaii

Polygala, Lewton's Polygala lewtonii Dicot Florida

Polygala, Tiny Polygala smallii Dicot Florida

Wireweed Polygonella basiramia Dicot Florida

Sandlace Polygonella myriophylla Dicot Florida

Po'e (Portulaca 

sclerocarpa) Portulaca sclerocarpa Dicot Hawaii

Potentilla, 

Hickman's Potentilla hickmanii Dicot California

Primrose, Maguire Primula maguirei Dicot Utah

Plum, Scrub Prunus geniculata Dicot Florida

Golden Sunburst, 

Hartweg's Pseudobahia bahiifolia Dicot California

Adobe Sunburst, 

San Joaquin Pseudobahia peirsonii Dicot California

kopiko Psychotria grandiflora Dicot Hawaii

Oahu wild coffee

Psychotria hexandra 

ssp. Oahuensis Dicot Hawaii

kopiko Psychotria hobdyi Dicot Hawaii

Kaulu (Pteralyxia 

kauaiensis) Pteralyxia kauaiensis Dicot Hawaii

kaulu Pteralyxia macrocarpa Dicot Hawaii

Harperella Ptilimnium nodosum Dicot

Alabama, North 

Carolina, South 

Carolina, Virginia, 

Cliffrose, Arizona

Purshia (=cowania) 

subintegra Dicot Arizona

Oak, Hinckley Quercus hinckleyi Dicot Texas
188

Remya kauaiensis 

(ncn) Remya kauaiensis Dicot Hawaii

Remya, Maui Remya mauiensis Dicot Hawaii

Remya 

montgomeryi (ncn) Remya montgomeryi Dicot Hawaii

Rhododendron, 

Chapman

Rhododendron 

chapmanii Dicot Florida

Sumac, Michaux's Rhus michauxii Dicot

North Carolina, 

Virginia

Gooseberry, 

Miccosukee Ribes echinellum Dicot

Florida, South 

Carolina

Watercress, 

Gambel's Rorippa gambellii Dicot California

Sanicula mariversa 

(ncn) Sanicula mariversa Dicot Hawaii

Sanicula purpurea 

(ncn) Sanicula purpurea Dicot Hawaii

Sandalwood, Lanai 

(='Iliahi)

Santalum haleakalae 

var. lanaiense Dicot Hawaii

Pitcher-plant, 

Green Sarracenia oreophila Dicot Alabama, Georgia

Pitcher-plant, 

Mountain Sweet

Sarracenia rubra ssp. 

jonesii Dicot South Carolina

Naupaka, Dwarf 

(Scaevola coriacea) Scaevola coriacea Dicot Hawaii

Schiedea, Diamond 

Head (Schiedea 

adamantis) Schiedea adamantis Dicot Hawaii

Ma'oli'oli (Schiedea 

apokremnos) Schiedea apokremnos Dicot Hawaii

(ncn) Schiedea attenuata Dicot Hawaii

Schiedea 

haleakalensis (ncn) Schiedea haleakalensis Dicot Hawaii

Schiedea helleri 

(ncn) Schiedea helleri Dicot Hawaii

Schiedea hookeri 

(ncn) Schiedea hookeri Dicot Hawaii

ncn (Schiedea 

jacobii) Schiedea jacobii Dicot Hawaii

Schiedea kaalae 

(ncn) Schiedea kaalae Dicot Hawaii
189

Schiedea kauaiensis 

(ncn) Schiedea kauaiensis Dicot Hawaii

Ma'oli'oli (Schiedea 

kealiae) Schiedea kealiae Dicot Hawaii

Schiedea 

membranacea 

(ncn) Schiedea membranacea Dicot Hawaii

Schiedea nuttallii 

(ncn) Schiedea nuttallii Dicot Hawaii

ncn (Schiedea 

salicaria) Schiedea salicaria Dicot Hawaii

Schiedea spergulina 

var. leiopoda (ncn)

Schiedea spergulina 

var. leiopoda Dicot Hawaii

Schiedea spergulina 

var. spergulina 

(ncn)

Schiedea spergulina 

var. spergulina Dicot Hawaii

Laulihilihi (Schiedea 

stellarioides) Schiedea stellarioides Dicot Hawaii

Reed-mustard, Clay

Schoenocrambe 

argillacea Dicot Utah

Reed-mustard, 

Barneby

Schoenocrambe 

barnebyi Dicot Utah

Reed-mustard, 

Shrubby

Schoenocrambe 

suffrutescens Dicot Utah

Chaffseed, 

American Schwalbea americana Dicot

Alabama, Florida, 

Georgia, North 

Carolina, South 

Carolina

Cactus, Pariette

Sclerocactus 

brevispinus Dicot Utah

Cactus, Colorado 

hookless Sclerocactus glaucus Dicot Colorado, Utah

Cactus, Mesa Verde

Sclerocactus mesaeverdae DicotColorado, New 

Mexico

Cactus, Uinta Basin 

hookless

Sclerocactus 

wetlandicus Dicot Utah

Cactus, Wright 

Fishhook Sclerocactus wrightiae Dicot Utah

Skullcap, Florida Scutellaria floridana Dicot Florida

Skullcap, Largeflowered Scutellaria montana Dicot Georgia, Tennessee
190

Roseroot, Leedy's

Sedum integrifolium 

ssp. leedyi Dicot

Minnesota, New 

York

Butterweed, 

Layne's Senecio layneae Dicot California

'Ohai (Sesbania 

tomentosa) Sesbania tomentosa Dicot Hawaii

'Anunu (Sicyos 

alba) Sicyos alba Dicot Hawaii

Checker-mallow, 

Keck's Sidalcea keckii Dicot

California, Oregon, 

Washington

Checker-mallow, 

Kenwood Marsh

Sidalcea oregana ssp. 

valida Dicot California

Silene hawaiiensis 

(ncn) Silene hawaiiensis Dicot Hawaii

Silene lanceolata 

(ncn) Silene lanceolata Dicot Hawaii

Silene perlmanii 

(ncn) Silene perlmanii Dicot Hawaii

Campion, Fringed Silene polypetala Dicot Florida, Georgia

Catchfly, Spalding's Silene spaldingii Dicot

Idaho, Montana, 

Oregon, 

Washington

Popolo Ku Mai 

(Solanum 

incompletum) Solanum incompletum Dicot Hawaii

Popolo 'Aiakeakua 

(Solanum 

sandwicense) Solanum sandwicense Dicot Hawaii

Goldenrod, Whitehaired Solidago albopilosa Dicot Kentucky

Goldenrod, 

Houghton's Solidago houghtonii Dicot Michigan

Goldenrod, Short's Solidago shortii Dicot Kentucky

Spermolepis 

hawaiiensis (ncn)

Spermolepis 

hawaiiensis Dicot Hawaii

Pinkroot, Gentian Spigelia gentianoides Dicot Florida

Spiraea, Virginia Spiraea virginiana Dicot

Georgia, Kentucky, 

North Carolina, 

Ohio, Tennessee, 

Virginia, 
191

Stenogyne 

angustifolia (ncn)

Stenogyne angustifolia 

var. angustifolia Dicot Hawaii

Stenogyne 

campanulata (ncn) Stenogyne campanulata Dicot Hawaii

Stenogyne 

kanehoana (ncn) Stenogyne kanehoana Dicot Hawaii

ncn (Stenogyne 

kauaulaensis) Stenogyne kauaulaensis Dicot Hawaii

(ncn) Stenogyne kealiae Dicot Hawaii

Wire-lettuce, 

Malheur

Stephanomeria 

malheurensis Dicot Oregon

Jewelflower, 

Metcalf Canyon

Streptanthus albidus 

ssp. albidus Dicot California

Snowbells, Texas Styrax texanus Dicot Texas

Sea-blite, California Suaeda californica Dicot California

Tetramolopium 

arenarium (ncn)

Tetramolopium 

arenarium Dicot Hawaii

Tetramolopium 

capillare (ncn)

Tetramolopium 

capillare Dicot Hawaii

Tetramolopium 

filiforme (ncn)

Tetramolopium 

filiforme Dicot Hawaii

Tetramolopium 

lepidotum ssp. 

lepidotum (ncn)

Tetramolopium 

lepidotum ssp. 

lepidotum Dicot Hawaii

Tetramolopium 

remyi (ncn) Tetramolopium remyi Dicot Hawaii

Tetramolopium 

rockii (ncn) Tetramolopium rockii Dicot Hawaii

(ncn)

Tetraplasandra 

bisattenuata Dicot Hawaii

(ncn) Tetraplasandra flynnii Dicot Hawaii

'Ohe'ohe 

(Tetraplasandra 

gymnocarpa)

Tetraplasandra 

gymnocarpa Dicot Hawaii

(ncn) Tetraplasandra lydgatei Dicot Hawaii

Meadowrue, 

Cooley's Thalictrum cooleyi Dicot Florida

Meadowrue, 

Cooley's Thalictrum cooleyi Dicot Georgia
192

Thelypody, 

Howell's 

Spectacular

Thelypodium howellii 

spectabilis Dicot Oregon

Mustard, SlenderpetaledThelypodium 

stenopetalum Dicot California

Penny-cress, 

Kneeland Prairie Thlaspi californicum Dicot California

Dogweed, Ashy

Thymophylla 

tephroleuca Dicot Texas

Townsendia, Last 

Chance Townsendia aprica Dicot Utah

Trematolobelia 

singularis (ncn)

Trematolobelia 

singularis Dicot Hawaii

Bluecurls, Hidden 

Lake

Trichostema 

austromontanum ssp. 

compactum Dicot California

Clover, Showy 

Indian Trifolium amoenum Dicot California

Clover, Running 

Buffalo Trifolium stoloniferum Dicot Kentucky, Missouri, 

Clover, Monterey Trifolium trichocalyx Dicot California

Tuctoria, Green's Tuctoria greenei Dicot California

Opuhe (Urera 

kaalae) Urera kaalae Dicot Hawaii

Vetch, Hawaiian 

(Vicia menziesii) Vicia menziesii Dicot Hawaii

Vigna o-wahuensis 

(ncn) Vigna o-wahuensis Dicot Hawaii

Pamakani (Viola 

chamissoniana ssp. 

chamissoniana)

Viola chamissoniana 

ssp. chamissoniana Dicot Hawaii

Viola helenae (ncn) Viola helenae Dicot Hawaii

Nani Wai'ale'ale 

(Viola kauaensis 

var. wahiawaensis)

Viola kauaiensis var. 

wahiawaensis Dicot Hawaii

Viola oahuensis 

(ncn) Viola oahuensis Dicot Hawaii

Warea, Wide-leaf Warea amplexifolia Dicot Florida

Mustard, Carter's Warea carteri Dicot Florida

akia Wikstroemia villosa Dicot Hawaii
193

Iliau (Wilkesia 

hobdyi) Wilkesia hobdyi Dicot Hawaii

Xylosma crenatum 

(ncn) Xylosma crenatum Dicot Hawaii

Yellowhead, Desert Yermo xanthocephalus Dicot Wyoming

A'e (Zanthoxylum 

dipetalum var. 

tomentosum)

Zanthoxylum dipetalum 

var. tomentosum Dicot Hawaii

A'e (Zanthoxylum 

hawaiiense)

Zanthoxylum 

hawaiiense Dicot Hawaii

a'e Zanthoxylum oahuense Dicot Hawaii

Ziziphus, Florida Ziziphus celata Dicot Florida

Fern, Pendant Kihi 

(Adenophorus 

periens) Adenophorus periens Ferns Hawaii

Asplenium fragile 

var. insulare (ncn)

Asplenium fragile var. 

insulare Ferns Hawaii

Fern, American 

hart's-tongue

Asplenium 

scolopendrium var. 

americanum Ferns

Michigan, 

Tennessee

Pauoa (Ctenitis 

squamigera) Ctenitis squamigera Ferns Hawaii

Diellia erecta (ncn) Diellia erecta Ferns Hawaii

Diellia falcata (ncn) Diellia falcata Ferns Hawaii

(ncn) Diellia mannii Ferns Hawaii

Diellia pallida (ncn) Diellia pallida Ferns Hawaii

Diellia unisora (ncn) Diellia unisora Ferns Hawaii

Diplazium 

molokaiense (ncn) Diplazium molokaiense Ferns Hawaii

(ncn) Doryopteris angelica Ferns Hawaii

(ncn) Doryopteris takeuchii Ferns Hawaii

aumakua, Palapalai

Dryopteris crinalis 

podosorus Ferns Hawaii

Wawae'Iole 

(Phlegmariurus 

(=Huperzia) mannii) Huperzia mannii Ferns Hawaii

Quillwort, Louisiana Isoetes louisianensis Ferns

Alabama, 

Mississippi
194

Quillwort, Blackspored Isoetes melanospora Ferns South Carolina

Wawae'Iole 

(Phlegmariurus 

(=Lycopodium) 

nutans)

Lycopodium 

(=Phlegmariurus) 

nutans Ferns Hawaii

'Ihi'Ihi (Marsilea 

villosa) Marsilea villosa Ferns Hawaii

Pteris lidgatei (ncn) Pteris lidgatei Ferns Hawaii

Snail, O'ahu Tree 

(Achatinella 

abbreviata) Achatinella abbreviata Gastropod Hawaii

Snail, O'ahu Tree 

(Achatinella 

apexfulva) Achatinella apexfulva Gastropod Hawaii

Snail, O'ahu Tree 

(Achatinella bellula) Achatinella bellula Gastropod Hawaii

Snail, O'ahu Tree 

(Achatinella buddii) Achatinella buddii Gastropod Hawaii

Snail, O'ahu Tree 

(Achatinella 

bulimoides) Achatinella bulimoides Gastropod Hawaii

Snail, O'ahu Tree 

(Achatinella 

byronii) Achatinella byronii Gastropod Hawaii

Snail, O'ahu Tree 

(Achatinella caesia) Achatinella caesia Gastropod Hawaii

Snail, O'ahu Tree 

(Achatinella casta) Achatinella casta Gastropod Hawaii

Snail, O'ahu Tree 

(Achatinella cestus) Achatinella cestus Gastropod Hawaii

Snail, O'ahu Tree 

(Achatinella 

concavospira)

Achatinella 

concavospira Gastropod Hawaii

Snail, O'ahu Tree 

(Achatinella curta) Achatinella curta Gastropod Hawaii

Snail, O'ahu Tree 

(Achatinella 

decipiens) Achatinella decipiens Gastropod Hawaii
195

Snail, O'ahu Tree 

(Achatinella 

decora) Achatinella decora Gastropod Hawaii

Snail, O'ahu Tree 

(Achatinella 

dimorpha) Achatinella dimorpha Gastropod Hawaii

Snail, O'ahu Tree 

(Achatinella 

elegans) Achatinella elegans Gastropod Hawaii

Snail, O'ahu Tree 

(Achatinella 

fulgens) Achatinella fulgens Gastropod Hawaii

Snail, O'ahu Tree 

(Achatinella 

fuscobasis) Achatinella fuscobasis Gastropod Hawaii

Snail, O'ahu Tree 

(Achatinella juddii) Achatinella juddii Gastropod Hawaii

Snail, O'ahu Tree 

(Achatinella juncea) Achatinella juncea Gastropod Hawaii

Snail, O'ahu Tree 

(Achatinella 

lehuiensis) Achatinella lehuiensis Gastropod Hawaii

Snail, O'ahu Tree 

(Achatinella 

leucorraphe) Achatinella leucorraphe Gastropod Hawaii

Snail, O'ahu Tree 

(Achatinella lila) Achatinella lila Gastropod Hawaii

Snail, O'ahu Tree 

(Achatinella livida) Achatinella livida Gastropod Hawaii

Snail, O'ahu Tree 

(Achatinella lorata) Achatinella lorata Gastropod Hawaii

Snail, O'ahu Tree 

(Achatinella 

mustelina) Achatinella mustelina Gastropod Hawaii

Snail, O'ahu Tree 

(Achatinella 

papyracea) Achatinella papyracea Gastropod Hawaii

Snail, O'ahu Tree 

(Achatinella 

phaeozona) Achatinella phaeozona Gastropod Hawaii
196

Snail, O'ahu Tree 

(Achatinella 

pulcherrima) Achatinella pulcherrima Gastropod Hawaii

Snail, O'ahu Tree 

(Achatinella 

pupukanioe) Achatinella pupukanioe Gastropod Hawaii

Snail, O'ahu Tree 

(Achatinella rosea) Achatinella rosea Gastropod Hawaii

Snail, O'ahu Tree 

(Achatinella 

sowerbyana) Achatinella sowerbyana Gastropod Hawaii

Snail, O'ahu Tree 

(Achatinella 

spaldingi) Achatinella spaldingi Gastropod Hawaii

Snail, O'ahu Tree 

(Achatinella 

stewartii) Achatinella stewartii Gastropod Hawaii

Snail, O'ahu Tree 

(Achatinella swiftii) Achatinella swiftii Gastropod Hawaii

Snail, O'ahu Tree 

(Achatinella 

taeniolata) Achatinella taeniolata Gastropod Hawaii

Snail, O'ahu Tree 

(Achatinella 

thaanumi) Achatinella thaahumi Gastropod Hawaii

Snail, O'ahu Tree 

(Achatinella 

turgida) Achatinella turgida Gastropod Hawaii

Snail, O'ahu Tree 

(Achatinella valida) Achatinella valida Gastropod Hawaii

Snail, O'ahu Tree 

(Achatinella 

viridans) Achatinella viridans Gastropod Hawaii

Snail, O'ahu Tree 

(Achatinella vittata) Achatinella vittata Gastropod Hawaii

Snail, O'ahu Tree 

(Achatinella 

vulpina) Achatinella vulpina Gastropod Hawaii

Campeloma, 

Slender Campeloma decampi Gastropod Alabama

Snail, Morro 

Shoulderband

Helminthoglypta 

walkeriana Gastropod California
197

Newcomb’s tree 

snail Newcombia cumingi Gastropod Hawaii

Butterfly, 

Uncompahgre 

Fritillary Boloria acrocnema Insect Colorado

Butterfly, San 

Bruno Elfin

Callophrys mossii 

bayensis Insect California

Beetle, Salt Creek 

Tiger

Cicindela nevadica 

lincolniana Insect Nebraska

Butterfly, Miami 

Blue

Cyclargus thomasi 

bethunebakeri Insect Florida

Beetle, Valley 

Elderberry 

Longhorn

Desmocerus 

californicus dimorphus Insect California

Beetle, Casey's 

June Dinacoma caseyi Insect California

Fly, Hawaiian 

picture-wing Drosophila aglaia Insect Hawaii

Fly, Hawaiian 

picture-wing Drosophila hemipeza Insect Hawaii

Fly, Hawaiian 

picture-wing Drosophila heteroneura Insect Hawaii

Fly, Hawaiian 

picture-wing

Drosophila 

montgomeryi Insect Hawaii

Fly, Hawaiian 

picture-wing Drosophila mulli Insect Hawaii

Fly, Hawaiian 

picture-wing Drosophila musaphilia Insect Hawaii

Fly, Hawaiian 

picture-wing

Drosophila 

neoclavisetae Insect Hawaii

Fly, Hawaiian 

picture-wing Drosophila obatai Insect Hawaii

Fly, Hawaiian 

picture-wing Drosophila ochrobasis Insect Hawaii

Hawaiian picturewing Fly Drosophila sharpi Insect Hawaii

Fly, Hawaiian 

picture-wing

Drosophila 

substenoptera Insect Hawaii

Fly, Hawaiian

picture-wing

Drosophila 

tarphytrichia Insect Hawaii

Beetle, Delta Green 

Ground Elaphrus viridis Insect California
198

Butterfly, Smith's 

Blue

Euphilotes enoptes 

smithi Insect California

Butterfly, Quino 

Checkerspot

Euphydryas editha 

quino (=E. e. wrighti) Insect California

Moth, Kern 

Primrose Sphinx Euproserpinus euterpe Insect California

Butterfly, Fender's 

Blue

Icaricia icarioides 

fenderi Insect Oregon

Butterfly, Mission 

Blue

Icaricia icarioides 

missionensis Insect California

Butterfly, Karner 

Blue

Lycaeides melissa 

samuelis Insect

Michigan, New 

York, Wisconsin

Moth, Blackburn's 

Sphinx Manduca blackburni Insect Hawaii

Crimson Hawaiian 

damselfly

Megalagrion 

leptodemas Insect Hawaii

Damselfly, Flying 

Earwig Hawaiian Megalagrion nesiotes Insect Hawaii

blackline Hawaiian 

damselfly

Megalagrion 

nigrohamatum 

nigrolineatum Insect Hawaii

Oceanic Hawaiian 

damselfly Megalagrion oceanicum Insect Hawaii

Damselfly, Pacific 

Hawaiian Megalagrion pacificum Insect Hawaii

Butterfly, Mitchell's 

Satyr

Neonympha mitchellii 

mitchellii Insect Michigan, Virginia

Beetle, American 

Burying

Nicrophorus 

americanus Insect

Kansas, Nebraska, 

Oklahoma, South 

Dakota, Texas

Skipper, Carson 

Wandering

Pseudocopaeodes 

eunus obscurus Insect California

Skipper, Laguna 

Mountain Pyrgus ruralis lagunae Insect California

Fly, Delhi Sands 

Flower-loving

Rhaphiomidas 

terminatus abdominalis Insect California

Dragonfly, Hine's 

Emerald Somatochlora hineana Insect Missouri

Butterfly, Callippe 

Silverspot

Speyeria callippe 

callippe Insect California
199

Butterfly, Behren's 

Silverspot

Speyeria zerene 

behrensii Insect California

Butterfly, Oregon 

Silverspot

Speyeria zerene 

hippolyta Insect

Oregon, 

Washington

Butterfly, Myrtle's 

Silverspot

Speyeria zerene 

myrtleae Insect California

Cladonia, Florida 

Perforate Cladonia perforata Lichen Florida

Lichen, Rock 

Gnome Gymnoderma lineare Lichen

North Carolina, 

South Carolina

Lichen, Rock 

Gnome Gymnoderma lineare Lichen Tennessee

Onion, Munz's Allium munzii Monocot California

Alopecurus, 

Sonoma

Alopecurus aequalis 

var. sonomensis Monocot California

Pa'iniu Astelia waialealae Monocot Hawaii

Brodiaea, Threadleaved Brodiaea filifolia Monocot California

Hillegrands 

reedgrass

Calamagrostis 

hillebrandii Monocot Hawaii

Lily, Tiburon 

Mariposa

Calochortus 

tiburonensis Monocot California

Sedge, White Carex albida Monocot California

Sedge, Navajo Carex specuicola Monocot Arizona

Kamanomano 

(Cenchrus 

agrimonioides) Cenchrus agrimonioides Monocot Hawaii

Amole, Purple

Chlorogalum 

purpureum var. 

purpureum Monocot California

Amole, Cammatta 

Canyon

Chlorogalum 

purpureum var. 

reductum Monocot California

Pu'uka'a (Cyperus 

trachysanthos) Cyperus trachysanthos Monocot Hawaii

Grass, Fosberg's 

Love Eragrostis fosbergii Monocot Hawaii

Lily, Minnesota 

Trout Erythronium propullans Monocot Minnesota

Fritillary, Gentner's Fritillaria gentneri Monocot Oregon

Seagrass, Johnson's Halophila johnsonii Monocot Florida
200

Beauty, Harper's Harperocallis flava Monocot Florida

Pink, Swamp Helonias bullata Monocot

North Carolina, 

South Carolina, 

Virginia

Iris, Dwarf Lake Iris lacustris Monocot Michigan

Hilo Ischaemum 

(Ischaemum 

byrone) Ischaemum byrone Monocot Hawaii

Pogonia, Small 

Whorled Isotria medeoloides Monocot

Georgia, Illinois, 

Michigan,New 

Jersey, New York, 

Pennsylvania, 

South Carolina, 

Tennessee, Virginia

Lily, Western Lilium occidentale Monocot California

Lily, Pitkin Marsh

Lilium pardalinum ssp. 

pitkinense Monocot California

Mariscus fauriei 

(ncn) Mariscus fauriei Monocot Hawaii

Mariscus 

pennatiformis (ncn) Mariscus pennatiformis Monocot Hawaii

Grass, Colusa Neostapfia colusana Monocot California

Beargrass, Britton's Nolina brittoniana Monocot Florida

Grass, California 

Orcutt Orcuttia californica Monocot California

Grass, San Joaquin 

Valley Orcutt Orcuttia inaequalis Monocot California

Panicgrass, Carter's 

(Panicum fauriei 

var.carteri)

Panicum fauriei var. 

carteri Monocot Hawaii

Lau'ehu (Panicum 

niihauense) Panicum niihauense Monocot Hawaii

Piperia, Yadon's Piperia yadonii Monocot California

Platanthera 

holochila (ncn) Platanthera holochila Monocot Hawaii

Orchid, Eastern 

Prairie Fringed Platanthera leucophaea Monocot

Illinois, Maine, 

Michigan, New 

York, Ohio, Virginia, 
201

Orchid, Western 

Prairie Fringed Platanthera praeclara Monocot

Iowa, Minnesota, 

Missouri, Nebraska, 

South Dakota, 

Wyoming

hala pepe Pleomele forbesii Monocot Hawaii

Hala Pepe 

(Pleomele 

hawaiiensis) Pleomele hawaiiensis Monocot Hawaii

Bluegrass, Mann's 

(Poa mannii) Poa mannii Monocot Hawaii

Bluegrass, Napa Poa napensis Monocot California

Bluegrass, 

Hawaiian Poa sandvicensis Monocot Hawaii

Poa siphonoglossa 

(ncn) Poa siphonoglossa Monocot Hawaii

Lo`ulu (Pritchardia 

affinis) Pritchardia affinis Monocot Hawaii

lo`ulu Pritchardia hardyi Monocot Hawaii

Lo`ulu (Pritchardia 

kaalae) Pritchardia kaalae Monocot Hawaii

Lo`ulu (Pritchardia 

napaliensis) Pritchardia napaliensis Monocot Hawaii

Lo`ulu (Pritchardia 

schattaueri) Pritchardia schattaueri Monocot Hawaii

Lo`ulu (Pritchardia 

viscosa) Pritchardia viscosa Monocot Hawaii

Arrowhead, 

Bunched Sagittaria fasciculata Monocot South Carolina

Water-plantain, 

Kral's Sagittaria secundifolia Monocot Alabama

Bulrush, 

Northeastern 

(=Barbed Bristle) Scirpus ancistrochaetus Monocot

Alabama, 

Pennsylvania, 

Virginia, 

Irisette, White

Sisyrinchium 

dichotomum Monocot South Carolina

Ladies'-tresses, 

Canelo Hills Spiranthes delitescens Monocot Arizona

Ladies'-tresses, Ute Spiranthes diluvialis Monocot

Colorado, Idaho, 

Montana, Nevada, 

Utah, Washington, 

Wyoming
202

Ladies'-tresses, 

Navasota Spiranthes parksii Monocot Texas

Trillium, Persistent Trillium persistens Monocot South Carolina

Trillium, Relict Trillium reliquum Monocot

Alabama, Georgia, 

South Carolina

Grass, Solano Tuctoria mucronata Monocot California

Grass, Tennessee 

Yellow-eyed Xyris tennesseensis Monocot Alabama, Georgia

Wild-rice, Texas Zizania texana Monocot Texas

Lizard, St. Croix 

Ground Ameiva polops Reptile Virgin Islands

Crocodile, 

American Crocodylus acutus Reptile Florida

Rattlesnake, New 

Mexican Ridgenosed

Crotalus willardi 

obscurus Reptile Arizona

Snake, Eastern 

Indigo

Drymarchon corais 

couperi Reptile

Alabama, Florida, 

Georgia, Mississippi

Skink, Blue-tailed 

Mole

Eumeces egregius 

lividus Reptile Florida

Lizard, Blunt-nosed 

Leopard Gambelia silus Reptile California

Tortoise, Gopher Gopherus polyphemus Reptile Mississippi

Turtle, Yellowblotched MapGraptemys 

flavimaculata Reptile Mississippi

Turtle, Ringed Map Graptemys oculifera Reptile Mississippi

Whipsnake 

(=Striped Racer), 

Alameda

Masticophis lateralis 

euryxanthus Reptile California

Skink, Sand Neoseps reynoldsi Reptile Florida

Snake, Northern 

Copperbelly Water

Nerodia erythrogaster 

neglecta Reptile Michigan, Ohio

Turtle, Alabama 

Red-bellied

Pseudemys 

alabamensis Reptile

Alabama, 

Mississippi

Turtle, Flattened 

Musk Sternotherus depressus Reptile Alabama

Snake, Giant Garter Thamnophis gigas Reptile California

Lizard, Coachella 

Valley Fringe-toed Uma inornata Reptile California
203