UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

WASHINGTON D.C., 20460 

OFFICE OF CHEMICAL SAFETY AND POLLUTION PREVENTION 

PC Code: 006329 

DP Barcode: D423845 

Date: May 18, 2015 

MEMORANDUM 

Subject: 

To: 

From: 

Registration Review: Problem Formulation for the Environmental Fate, Ecological Risk, 

Endangered Species, and Drinking Water Assessmen ts for Acequinocyl 

Meg Hathaway, Chemical Review Manager 

Dana Friedman, Acting Team Leader/Cathryn Britton, Team Leader 

Kevin Costello, Branch Chief 

Risk Management and Implementation Branch II 

Pesticide Re-Evaluation Division (7508P/ ,,4.. /a_ S/J.1/,SFreeborn Jewett, M.S., Biologist ~ ~~ft Michael Lowit, Ph.D., Ecologist ~ M . s· I; ' I. 

Sujatha Sankula, Ph.D., Branch Chief ( ,· <J-"-- '/_!./'/~{ c 

Environmental Risk Branch I / \ : = 5 l \€ l "') 

Environmental Fate and Effects Division (7507P) 

1 
2

1. Executive Summary:

The Environmental Fate and Effects Division (EFED) has completed the problem formulation for the 

environmental fate, ecological risk, endangered species, and drinking water exposure assessments to be 

conducted as part of the Registration Review of the miticide acequinocyl. Functioning as the first stage 

of the risk assessment process for Registration Review, this problem formulation provides an overview 

of what is currently known about the environmental fate and ecological effects associated with 

acequinocyl and its degradates. It also describes the preliminary ecological risk hypothesis and analysis 

plan for evaluating and characterizing drinking water exposure and risk to non-target species and the 

environment in support of the Registration Review of acequinocyl. This document also recommends 

studies that should be included in a data call-in (DCI) to address uncertainties surrounding the 

environmental fate and potential ecological effects of acequinocyl.

Recommended Studies:

Ecological Effects

 Guideline 850.1025- Estuarine/marine invertebrate acute toxicity using mollusk (TGAI)

 Guideline 850.2100: Avian acute oral toxicity- with a passerine species (TGAI)

 Guideline 850.1400- Freshwater fish early-life stage (TGAI)

 Guideline 850.1400- Estuarine/marine fish early-life stage (TGAI)

 Guideline 850.4400- Aquatic vascular plant toxicity test (TEP)

 Guideline 850.4500- Estuarine/marine diatom toxicity test using Skeletonomea costatum (TEP)

 Guideline 850.4500- Freshwater diatom toxicity test using Navicula pelliculosa (TEP)

 Guideline 850.4550- Blue green algae toxicity test using Anabaena flos-aquae (TEP)

 Non Guideline- Whole sediment chronic invertebrates- freshwater midge Chironomus dilutus, 

freshwater amphipod Hyalella azteca, and estuarine/marine amphipod Leptocheirus 

plumulosus1(TGAI)2

 Non Guideline Tier I: Honeybee adult chronic oral exposure (TGAI)

 Non Guideline Tier I: Honeybee larval acute and chronic oral exposure (TGAI)

 Non-Guideline Tier II: Residue in pollen and nectar (recommendation pending risks identified in 

Tier I studies) (TEP)

 Guideline 850.3040: Tier II semi-field testing for pollinators (tunnel and feeding studies) 

(recommendation pending risks identified in Tier I studies) (TEP)

 Guideline 850.3040: Tier III full-field testing for pollinators (recommendation pending risk 

identified in Tier II studies) (TEP)

1EFED acknowledges that acequinocyl stability issues have been reported in estuarine/marine 

invertebrate tests that resulted in a waiver for the chronic estuarine/marine invertebrate study (USEPA, 

2010). If chemical stability is an issue during the chronic testing with a marine/estuarine amphipod

species, consulting with EFED scientists about other testing options may be possible. 

2As indicated in 40 CFR Part 158, the registrant is required to submit a protocol for approval prior to 

initiating studies with each of the three invertebrate species. 
3

Fate

Although fate data are available, there are data gaps for all guideline requirements triggered for 

acequinocyl uses (except terrestrial field dissipation) because of the numerous issues with the 

available studies (described in Section 11). In general, there is uncertainty for most of the 

studies about whether or not degradation rates were overestimated because there are 

unresolved questions about the potential contribution of non-experimental related sources of 

degradation that may have occurred during the course of the studies. It would be ideal to 

collectively address the data gaps (outlined in Table 7) for all of the fate studies; however, the 

ecological risk assessment and drinking water assessment (DWA) may proceed based on the

available data by making conservative assumptions as in past risk assessments. Two approaches 

may be used to bound aquatic estimated environmental concentrations (EECs):

 In Approach 1, acequinocyl will conservatively be assumed to be stable to all routes of 

degradation because of the uncertainties associated with the environmental fate data, 

mainly the lack of validation of the analytical methods and the lack of storage stability 

data.

 In Approach 2, it will be assumed that the half-lives of acequinocyl and the degradation 

product 2-dodecyl-3-hydroxy-1,4-naphthalenedione aka 2-dodecyl-3-hydroxy-1,4-

naphthoquinone or R1 (hereinafter R1) are accurate and total toxic residues 

(acequinocyl + R1) will be modeled to address toxicity concerns with R1. Uncertainties 

about degradation rates would need to be addressed for all studies in order to move 

away from conservative assumptions such as those outlined above (i.e., approach 1). 

Addressing other issues such as testing on additional soils (e.g. aerobic soil metabolism) 

is expected to have little impact on the risk assessment unless issues with the existing 

studies surrounding potential overestimation of degradation rates are addressed first; 

thereby, potentially allowing the risk assessment to move away from the assumption of 

stability (upper bound EEC). Despite uncertainties in the fate data, EECs based on both 

approaches led to the same conclusions in past risk assessments; that is, the greatest 

risk to the aquatic environment from use of acequinocyl is direct effects on invertebrate 

species. On the other hand, reliance on potentially conservative assumptions may lead 

to overly conservative mitigation measures to protect endangered aquatic species. 

2. Introduction

The purpose of this problem formulation is to provide an understanding of what is known about the 

environmental fate and ecological effects of acequinocyl, considering its currently registered uses. This 

document will provide a plan for analyzing data relevant to acequinocyl and for conducting ecological 

risk, endangered species, and drinking water exposure assessments for its registered uses. This problem 

formulation is intended to identify data gaps, uncertainties, and potential assumptions used to address 

those uncertainties relative to characterizing the ecological risk associated with the registered uses of 

acequinocyl.

Acequinocyl (CAS: 57960-19-7; PC Code: 006329; (2-(acetyloxy)-3-dodecyl-1,4-naphthalenedione)) is a 

miticide belonging to the quinoline class of chemicals. Acequinocyl is registered for commercial use 

under the name of Kanemite 15 SC (15.8% a.i.) (EPA reg. #66330-38) for the control of various mite 

species (USEPA, 2014a). In the U.S., acequinocyl is labeled for use on tree nuts, pistachios, citrus, 

climbing vine fruits, pome fruits, fruiting vegetables, low growing berries, caneberries, cherries, 
4

succulent shelled beans, melons, cucumbers, okra, edible podded beans, succulent soybean, hops, and 

landscape ornamentals. Acequinocyl is applied by foliar spray application using ground equipment at a 

maximum single application rate of 0.3 lbs a.i./A with a maximum of two applications annually.

3. Use Characterization

a. Mode of Action

Acequinocyl belongs to the quinoline class of chemicals. Upon application, acequinocyl hydrolyzes to 

hydroxy-acequinocyl (R1) in the mite body and binds to the Qo center at complex III in mitochondria. 

The net result is the blockage of cellular respiration and other adverse metabolic effects in mites, 

although it is not clear at this point what proportion of the miticidal action is through the parent and 

which is through the metabolite R1. Acequinocyl has no systemic activity but provides contact control of 

all life stages of mites.

b. Overview of Pesticide Use and Usage

The Biological and Economic Analysis Division (BEAD) provided a Screening Level Usage Analysis (SLUA) 

(USEPA, 2014a) to provide estimates of the actual usage of acequinocyl on agricultural crops. 

The screening level usage profile (SLUA) produced by BEAD and located in the docket (USEPA, 2014a)

and summarized in Table 1, lists the use patterns for the current uses of acequinocyl. Primary uses in 

terms of average weight of applied product of acequinocyl are almonds, apples, oranges, and 

strawberries. These data represent annual data from 2004-2012.

Appendix 2 summarizes the application rates of acequinocyl for all labeled uses. 

Table 1: Estimates of the Actual Usage of Acequinocyl on Agricultural Crops.

Crop

Average 

Annual Lbs. 

A.I.

Percent Crop Treated

Average Maximum

Almonds 1,000* <1 <2.5

Apples 1,000 <2.5 <2.5

Grapefruit <500 <2.5 <2.5

Grapes <500 <1 <2.5

Lemons <500 <2.5 <2.5

Oranges 1,000 <1 <2.5

Pears <500 <1 <2.5

Strawberries 10,000 5 10

Tangerines <500 <2.5 5

Walnuts <500 <1 <2.5

*All numbers rounded.
5

4. Conclusions from Previous Risk Assessments

a. Ecological Risk Assessment

Acequinocyl was first assessed in 2003. Since then, the Agency has conducted multiple ecological risk 

assessments on acequinocyl. The most recent risk assessment was carried out in 2011 in Succulent 

Soybean, Low Growing Berry, Small Fruit Vine Climbing (except kiwifruit), Succulent Shelled Beans, 

Cowpea Forage, Caneberry, Melon, Cucumber, and Cherry (D448205). A full list of previous acequinocyl 

risk assessments is available in Appendix 1. The direct risk concerns identified in past assessments are:

 Freshwater Invertebrates (Acute listed and non-listed and Chronic listed and non-listed) 

 Estuarine/Marine Invertebrates (Acute listed and non-listed and Chronic listed and non-listed) 

 Mammals (Chronic listed and non-listed) 

 Terrestrial Invertebrates (Assumed based on lack of acceptable endpoints) 

 Birds (Chronic listed and non-listed)

b. Drinking Water Exposure Assessments

The most recent DWA was conducted in 2011 (DP389520). Two approaches were used to estimate 

drinking water concentrations (EDWCs) due to uncertainties associated with the available 

environmental fate data. In Approach 1, acequinocyl was assumed to be stable to all routes of 

degradation. In Approach 2, it was assumed that the half-lives of acequinocyl and the degradation 

product R1 were accurate and total toxic residues (acequinocyl + R1) were modeled to address toxicity 

concerns with both acequinocyl and R1.

Some EDWCs exceed the solubility limit of acequinocyl (6.69 μg/L at 20°C); therefore, in those cases the 

recommended EDWCs are equal to the solubility limit. The acute EDWC = 6.69 μg/L (Approach 1) and 

5.59 μg/L (Approach 2). The annual mean (chronic) EDWC = 6.69 μg/L (Approach 1) and 1.36 μg/L

(Approach 2). The 30-year annual mean EDWC = 6.69 μg/L (Approach 1) and 0.27 μg/L (Approach 2). 

The ground water concentration = 3.6 x 10-3 μg/L (acute and chronic).

c. Clean Water Act Programs

Acequinocyl is not identified as a cause of impairment for any bodies listed as impaired under section 

303(d) of the Clean Water Act (as of 11/2014).1 A Total Maximum Daily Load (TMDL) has not been 

developed.2 The Agency invites submission of water quality data for this pesticide. To the extent 

possible, data should conform to the quality standards in Appendix A of the OPP Standard Operating 

Procedure: Inclusion of Impaired Water Body and Other Water Quality Data in OPP’s Registration Review 

Risk Assessment and Management Process3, in order to ensure they can be used quantitatively or 

qualitatively in pesticide risk assessments.

 

1http://iaspub.epa.gov/tmdl_waters10/attains_nation_cy.cause_detail_303d?p_cause_group_id=885

2http://iaspub.epa.gov/tmdl_waters10/attains_nation.tmdl_pollutant_detail?p_pollutant_group_id=885&p_pollut

ant_group_name=PESTICIDES

3http://www.epa.gov/oppfead1/cb/ppdc/2006/november06/session1-sop.pdf
6

5. Environmental Fate and Transport

Acequinocyl appears to undergo fairly rapid transformation in most aquatic and terrestrial 

environments. Acequinocyl undergoes rapid hydrolysis under neutral and alkaline pH conditions with a 

half-life of 1.26 hours to less than 2 days. However, it is more stable under acidic pH conditions (e.g., 75 

days at pH 4). Photodegradation in water appears to occur even more quickly with half-lives of less than 

15 minutes in sterile lab and river water. In contrast, available data provides no evidence of 

photodegradation in soil. Aerobic biotransformation in soil was also rapid with half-lives less than 2 

days under laboratory conditions. Acequinocyl also dissipated quickly in aquatic metabolism studies 

(half-lives < 1 day); however, hydrolysis may have contributed to the observed degradation. Under field 

conditions, acequinocyl applied to bare plots dissipated with half-lives ranging from 2 hours in California 

to 14 hours in New York. In contrast, magnitude of residue studies showed longer half-lives (mean halflife of 20 days based on apples, pears, oranges, grapefruit, lemon, and almonds; USEPA, 2004a). 

Vapor pressure (1.69 x 10-6 Pa at 25 °C) and Henry's Law Constant (9.59 x10-7 atm x m3/mol) indicate a 

low possibility of volatilization of acequinocyl from soil and water. 

Acequinocyl is expected to exhibit low mobility in soil. The soil adsorption Kd for acequinocyl ranged 

from 678 ml/g in sandy loam soil to 1,620 ml/g in silty clay loam soil. One of the major degradation 

products, R1, is slightly more mobile than acequinocyl under some conditions (Kd ranged from 27 ml/g 

in silt loam to 3,400 ml/g in sandy loam soil). In the field studies, acequinocyl and the observed 

degradates (R1 and AKM-18) were not detected below 0-15 cm soil depth.

Acequinocyl has a tendency to bioconcentrate based on the bioconcentration factor (BCF) in fish (307 to 

387) and high octanol/water partition coefficient (Log Pow ≥ 6.2). However, the depuration half-life is 

less than 1 day. The physical, chemical, and environmental fate properties of acequinocyl are 

summarized in Table 2.

a. Transformation Products

The major degradation products (formation > 10% of applied acequinocyl) most often detected in the 

laboratory and field studies were R1 (2-dodecyl-3-hydroxy-1, 4-napthoquinone) and AKM-18 (2-(1,2-

dioxotetradecyl) benzoic acid). AKM-08 (2-(2-oxo-dodecyl)-3-hydroxy-1,4-naphthoquinone), o-phthalic 

acid, and phenol were major degradates only in the aqueous photolysis study. CBAA (2-carboxy-α-oxobenzene acetic acid) was a major degradate only in the aerobic aquatic metabolism study. Fate data are 

not available for the major degradation products with the exception of the batch equilibrium study for 

R1. Appendix 3 summarizes the maximum formation of major acequinocyl degradation products.

Table 2. Physical, Chemical, and Environmental Fate Properties of Acequinocyl

Parameter Value Reference Comments

Chemical Acequinocyl

Chemical Name 2-(acetyloxy)-3-dodecyl-1,4-

naphthalenedione

Empirical Formula C24H32O4 MRID 45434901

CAS Number 57960-19-7
7

Parameter Value Reference Comments

Structure MRID 45434909

SMILES C(CCCCCCCCCCC)C1=C(C(=O)(c2

c(cccc2)C1(=O)))OC(=O)C

EPI Suite v 4.11

Selected Physical/Chemical Parameters

Molecular mass 384.5 MRID 45434901

Water Solubility (20°C) 6.69 μg/L MRID 45434906

Log Pow ≥6.2

Vapor pressure (25°C) 1.69 x 10-6 Pa MRID 45434905

Henry’s law constant 9.59 x10-7 atm·m3/mol Calculated

Persistence2

Hydrolysis (t 1⁄2 ) 19 days (pH 1.2)

75 days (pH 4)

1.6 days (pH 7)

1.26 hours (pH 9)

MRID 45434908

Supplemental

Aqueous Photolysis (t 1⁄2 ) 14 minutes 

(buffer solution, pH 5)

12 minutes 

(sterile river water, pH 7.8)

MRID 45434909

Supplemental

Soil Photolysis (t 1⁄2 ) Stable* MRID 45434910

Supplemental

*Rate of degradation was 

the same in irradiated 

samples (t 1⁄2 = 2.0 days) 

and dark controls (t 1⁄2 = 

1.9 days)

Aerobic Soil Metabolism (t 1⁄2 ) < 2 days (visual) MRID 45434911

Supplemental

Aerobic Aquatic Metabolism (t 1⁄2 ) 8.5 and 9.8 hours (total system) MRID 45434914

Supplemental 

Degradation likely driven 

by hydrolysis given that 

the system pH ~ 8.

Anaerobic Aquatic Metabolism (t 1⁄2 ) < 1 day (visual, total system) MRID 45434913

Supplemental

Mobility

Kd 678-1620 mL/g (acequinocyl)

27-3400 mL/g (R1)

MRID 45531902

Supplemental

MRID 45434907

Supplemental

Field Dissipation

Terrestrial Field Dissipation (t 1⁄2 ) 2-14 hours MRID 45651601

Acceptable

O

O

CH2(CH2)10CH3 OCOCH3
8

Parameter Value Reference Comments

Bioaccumulation

Bioaccumulation in Common Carp

(Depuration t 1⁄2)

(BCF)

< 1 day* (whole fish)

307-387 (whole fish)

* 80% depuration after 1 

day

1 http://www.epa.gov/opptintr/exposure/pubs/episuite.htm

2 Half-lives based on acequinocyl + R1 residues may be recalculated at the time of risk assessment using the most 

up-to-date guidance (acequinocyl + R1 residue half-lives are presented in DP285811+, USEPA, 2004a).

6. Receptors

Consistent with the process described in the Overview Document (USEPA, 2004a), the risk assessment 

for acequinocyl relies on a surrogate species approach. Toxicological data generated from surrogate 

test species, which are intended to be representative of broad taxonomic groups, will be used to 

extrapolate the potential effects on a variety of species (receptors) included under these taxonomic 

groupings. Table 3 and Table 4 provide a summary of the aquatic and terrestrial taxonomic groups, 

respectively, and the most sensitive surrogate species tested to characterize the potential acute and 

chronic effects of acequinocyl. Appendix 4 provides a full listing of the aquatic animal and plant toxicity 

endpoints for acequinocyl, as well as expanded explanations about the validity of the endpoints for risk 

assessments. Table 5 provides information for the degradate R1. Empirically-measured toxicity data 

were not provided for major degradates AKM 18, AKM-08, o-Phthalic acid, Phenol, and CBAA. Estimates 

of the toxicities of these degradates are available in Table 6. Based on available ecotoxicity information, 

acequinocyl is very highly toxic to freshwater aquatic invertebrates. Acequinocyl is highly toxic to 

estuarine/marine fish and invertebrates, moderately toxic to freshwater fish, and slightly toxic to rats via 

inhalation. Acequinocyl is practically nontoxic to rats (acute oral exposure), birds, and honeybees (adult 

contact). 

a. Effects to Aquatic Organisms

Aquatic invertebrates are the most sensitive taxa to acequinocyl exposure. Chronic toxicity data are 

available for freshwater invertebrates, but are not available for estuarine/marine invertebrates. A 

waiver request was granted for assessing chronic exposure to estuarine/marine invertebrates under 

chronic, flow-through conditions due to the fact that under experimental conditions, acequinocyl was 

not sufficiently stable to ensure desired exposure concentrations (USEPA 2010). This waiver applies to 

chronic studies, as stability was not as prevalent of an issue in acute studies. As a result, for the 

purposes of risk assessment, an estimated chronic toxicity value for estuarine/marine invertebrates will 

be estimated by taking an acute to chronic ratio (ACR) for water flea endpoints (MRIDs 46372101; 

45434922) (2.4μg/L/0.98μg/L=2.45) and applying it to the most sensitive acute endpoint for an 

estuarine/marine invertebrate species, which is mysid shrimp (MRID 45434917) (0.94 μg/L/2.45=0.38

μg/L). 

Several studies presented in Table 3 were classified as supplemental because of low % recovery of the 

chemical. Unless specified otherwise in the “MRID & status” column of Table 3, these studies may be 

used quantitatively in risk assessments, as the low % recovery was consistent across all aquatic studies 

and degradation is presumed to result in conversion to major degradate R1. The R1 degradate is 

assumed to be of equal toxicity to acequinocyl to aquatic taxa, based on available aquatic toxicity data 

and results of ECOSAR toxicity modeling shown in Table 5 and Table 6.
9

Part of the registration review process involves reviewing previously submitted studies to ensure that 

the study classifications reflect current guideline requirements. Three studies were submitted that 

tested the acute toxicity of acequinocyl TEP to bluegill sunfish (Lepomis macrochirus) (MRID 45428605), 

rainbow trout (Oncorhynchus mykiss) (MRID 45530601) and sheepshead minnows (Cyprinodon 

variegatus) (MRID 45428606). These studies were initially classified as acceptable, but will be 

downgraded based on the presence of a precipitate that was not centrifuged or filtered prior to analysis.

The study measuring acute toxicity to rainbow trout (Oncorhynchus mykiss) (MRID 45530601) will be 

downgraded to invalid because a dose response was observed, but endpoints could not be determined

because of uncertainty related to the bioavailability of the exposure concentrations. The studies 

measuring acute toxicity to sheepshead minnows (Cyprinodon variegatus) (MRID 45428606) and bluegill 

sunfish (Lepomis macrochirus) (MRID 45428605) will be downgraded to supplemental because no 

effects were observed at any concentrations, and exposure concentrations are assumed to be the limit 

of solubility (6.69 ppb). DERs for these studies will be modified to reflect these classification changes.

Table 3: Most Sensitive Aquatic Toxicity Endpoints for Acequinocyl 

Taxa Study Type % ai Species Toxicity Value & 

Category

MRID & 

Status

Endpoints 

Affected

Freshwater 

Fish

Acute 

850.1075

97.1 Bluegill Sunfish

Lepomis 

macrochirus

LC50>1.1 mg ai/L

NOAEC= 1.1 mg ai/L

Moderately toxic

45434918

Supplemental

Endpoints are 

valid for risk 

assessment.

None

Freshwater 

Invertebrates

Acute

850.1010

98.3 Water Flea 

Daphnia magna

LC50= 2.7 μg ai/L

NOAEC= 0.66 μg ai/L

Very highly toxic

46372101

Acceptable

Mortality and 

sublethal 

effects 

(lethargy)

Chronic

850.1300

98.3 Water Flea

Daphnia magna

NOAEC= 0.98 μg ai/L

LOAEC= 1.8 μg ai/L

45434922

Supplemental

Endpoints 

valid for risk 

assessment

Number of 

young, length 

and dry weight

Estuarine/ 

Marine Fish

Acute 

850.1075

97.1 Sheepshead 

minnow

Cyprinodon 

variegatus

LC50> 0.19 mg ai/L

NOAEC= 0.19 mg ai/L

Highly Toxic

45434921

Supplemental 

Endpoints 

valid to 

quantitatively 

assess risk. 

None

Estuarine/ 

Marine 

Invertebrates

Acute 

850.1035

97.1 Mysid shrimp 

Americamysis

bahia

LC50=0.94 μg ai/L

NOAEC= 0.27 μg ai/L

Highly Toxic

45434917

Supplemental 

Endpoints 

valid to 

quantitatively 

assess risk. 

Lethargic 

swimming, loss 

of equilibrium
10

Taxa Study Type % ai Species Toxicity Value & 

Category

MRID & 

Status

Endpoints 

Affected

Chronic

850.1350

NA Mysid Shrimp

Americamysis

bahia

NOAEC: 0.38 μg ai/L

(Estimated using Acute 

to Chronic Ratio (ACR))

NA NA

Aquatic 

Plants

Non Vascular

850.4400

97.1 Green Algae

Pseudokirchneriella 

subcapitata

72-hour EC50=0.96 mg 

a.i./L 

NOAEC = 0.0017 mg 

ai/L

45435008

Supplemental

Endpoints can 

be used to 

quantitatively

assess risk to 

non-vascular 

aquatic plants. 

Study was 

conducted for 

72 hours,

shorter than 

the 

recommended 

96-120 hour, 

yet the 

toxicity 

endpoint is 

several orders 

of magnitude 

above the 

limit of 

solubility for 

this chemical, 

so a new 

study would 

be unlikely to 

change risk 

conclusions. 

None

a. Effects to Terrestrial Organisms

Table 4: Most Sensitive Terrestrial Toxicity Endpoints for Acequinocyl 

Taxa Study Type % ai Species Toxicity Value & 

Category

MRID & 

Status

Endpoints 

Affected

Mammals

Acute oral 

870.1100

96.8 Rat 

Rattus norvegicus

LD50> 5000 mg/kg-bw

(Males and Females)

Practically nontoxic

45435011

Acceptable

None
11

Taxa Study Type % ai Species Toxicity Value & 

Category

MRID & 

Status

Endpoints 

Affected

Chronic 

870.3800

97.1 Rat 

Rattus norvegicus

Parental 

NOAEL (m)= 100 

mg/kg-diet

LOAEL (m)= 800 mg/kgdiet

Offspring

NOAEL= 100 mg/kgdiet

LOAEL= 800 mg/kg-diet

45531909

Acceptable

None

Acute 

Inhalation

96.5 Rat 

Rattus norvegicus

LC50> 0.84 mg/L

Males and Females

Slightly Toxic

45435013

Acceptable

Mortality

Birds

Acute Oral

850.2100

98.4 Mallard Duck 

Anas platyrhynchos

LD50> 2000 mg ai/kgbw

NOAEL= 2000 mg ai/kgbw

Practically nontoxic

48660601

Acceptable

None

Acute Dietary

850.2200

15.6 Northern 

Bobwhite Quail

Colinus virginianus

LC50> 5970 mg ai/kg 

diet

NOAEC= 5970 mg ai/kg 

diet

Practically nontoxic

46622701

Acceptable

None

Chronic

850.2300

97.1 Mallard Duck

Anas platyrhynchos

NOAEC= 100 mg/kgdiet 

LOAEC= 500 mg/kg-diet

45435005

Acceptable

Female body 

Weight gainTerrestrial 

Invertebrates

Adult Acute 

Contact

850.3020

97.1 Honeybee Apis 

mellifera

48-hr LD50> 100 μg 

ai/bee

NOAEL= 100 μg ai/bee

Practically Nontoxic

45435007

Acceptable

None

Adult Acute 

Oral

15.4 Honeybee Apis 

mellifera

72-hr LD50> 315 μg 

ai/bee

NOAEL= 43.8 μg ai/bee

45428608

Supplemental

Acceptable for 

use in risk 

assessment

None

Terrestrial 

Plants

Seedling 

Emergence 

Monocot

850.4100

15.3 Oat (Avena sativa)

Onion (Allium 

cepa)

Corn (Zea mays)

EC25>0.9 lb ai/a

NOAEC= 0.9 lb ai/a

No effect for all species

45428609

Acceptable

None
12

Taxa Study Type % ai Species Toxicity Value & 

Category

MRID & 

Status

Endpoints 

Affected

Ryegrass (Lolium 

perenne)

Seedling 

Emergence 

Dicot

850.4100

15.3 Carrot (Daucus 

carota)

Rapeseed (Brassica 

napus)

Sugarbeet (Beta 

vulgaris)

Tomato (Solanum

Lycopersicum)

Cabbage (Brassica 

oleracea)

Soybean (Glycine 

max)

EC25= 0.7 lb ai/a

NOAEC= 0.3 lb ai/a

Most sensitive species: 

Carrot

45428609

Acceptable

Shoot Height

Vegetative 

Vigor 

Monocot

850.4150

15.3 Oat (Avena sativa)

Onion (Allium 

cepa)

Corn (Zea mays)

Ryegrass (Lolium 

perenne)

EC25> 0.9 lbs ai/a

NOAEC= 0.9 lbs ai/a

No effect for all species

45428610

Acceptable

None

Vegetative 

Vigor 

Dicot

850.4150

15.3 Carrot (Daucus 

carota)

Rapeseed (Brassica 

napus)

Sugarbeet (Beta 

vulgaris)

Tomato (Solanum

Lycopersicum)

Cabbage (Brassica 

oleracea)

Soybean (Glycine 

max)

EC25> 0.9 lbs ai/a

NOAEC= 0.3 lbs ai/a

Most sensitive species: 

Beets, cabbage

45428610

Acceptable

Shoot Height

b. Degradate toxicity

Two studies were submitted that compared the acute toxicity of acequinocyl and R1 to the most 

sensitive aquatic species, the water flea (Daphina magna) (LC50 acequinocyl= 2.7 μg ai/L; LC50 R1= 2.4 

μg ai/L). The results of these studies (Table 5) indicate that acute exposure of acequinocyl and the R1 

degradate are of equal toxicity to aquatic freshwater invertebrates. A study carried out with the

common carp (Cyprinus carpio) (MRID 46370502) did not observe toxicity effects for acequinocyl or R1 

up to a maximum concentration of 1.1 mg ai/L. Toxicity data were not available for major degradates 

AKM 18, AKM 08, o-Phthalic acid, Phenol, CBAA. A full list of the major degradates and their chemical 

properties is available in Appendix 3.
13

Table 5: Toxicity Endpoints of Acequinocyl and the Major Acequinocyl Degradate H-Acequinocyl (R1) 

Taxa Study Type Compound Species Toxicity Value & 

Category

MRID & 

Status

Freshwater 

Invertebrate

Acute 

850.1010

Acequinocyl 

97.0%

Water Flea

Daphnia magna

LC50= 2.7 μg 

ai/L

NOAEC= 0.66 μg 

ai/L

Very highly 

Toxic

46372101

Acceptable

Freshwater 

Invertebrate

Acute 

850.1010

R1

96.9%

Water Flea

Daphnia magna

LC50= 2.4 μg 

ai/L

NOAEC= 1.7 μg 

ai/L

Very Highly 

Toxic

46372101

Acceptable

Freshwater 

Invertebrate

Acute 

850.1010

Mixture 

composed of 

equal parts:

Acequinocyl

97.0%

+

R1 96.9%

Water Flea

Daphnia magna

LC50= 5.2 μg 

ai/L

NOAEC= 1.5 μg 

ai/L

Very Highly 

Toxic

46372101

Acceptable

Freshwater 

Fish

Acute

850.1075

R1 

99.3%

Common Carp

Cyprinus carpio

LC50>2.3 mg 

ai/L

NOAEC= 2.3 mg 

ai/L

Moderately 

Toxic

46370502

SupplementalNon guideline 

test species 

and was 

conducted as 

a limit test. 

Endpoint can 

be used to 

quantitatively 

assess risk. 

ECOSAR was used to predict toxicity of the major degradates (>10% formation) R1, AKM 18, AKM 08, oPhthalic acid, Phenol, and CBAA. ECOSAR uses quantitative structure activity relationships (QSAR) to 

predict effects of acute exposure to aquatic species. Reliability of the predictive capacity of ECOSAR 

modeling is determined based on how closely the modeling program can estimate the toxicity of the 

parent compound. 

Similarities between empirically-derived toxicity values for the parent or the R1 degradate and the 

toxicity values predicted by ECOSAR indicated that predicted toxicity values provided meaningful 

indications of acute and chronic exposure toxicity of acequinocyl degradates to the most sensitive 
14

aquatic taxa, Daphnia magna, as well as exposure to green algae. Based on a similar comparison of 

ECOSAR-predicted toxicity values of acequinocyl to freshwater and estuarine/marine fish with the 

predicted values generated by ECOSAR, there was no confidence in these predicted values. The ECOSAR 

output for daphnia and green algae are available in Table 6.
15

Table 6: Acute and Chronic Values (μg ai/L) Predicted through ECOSAR Modeling

Exposure 

(Acute/ 

Chronic) 

Taxa

Parent Degradate

Acequinocyl

Toxicity (from 

studies)

Acequinocyl

(Predicted)

R1

(From 

studies)

R1

(predicted)

AKM 18 AKM 08 o-Phthalic 

acid

Phenol CBAA

Acute Daphnia 

magna

LC50

2.7 8 2.4 12 540 59 4,858,623 9,295 365,026 

Chronic Daphnia 

magna

NOAEC

0.98 9 -- 3 149 451 373,177 1,770 43,360

Acute Green Algae 960 34 -- 34 1889 15 2,538,352 44,824 1,028,138 

1Estimated by ECOSAR program using Acute to Chronic toxicity ratio
16

ECOSAR modeling does not provide evidence that major degradates R1 and AKM 08 are more or less 

toxic than acequinocyl, as the predicted toxicities of these degradates are similar to the measured 

toxicity endpoints of acequinocyl. In the case of R1, this was verified empirically, as discussed above. The 

degradates AKM-18, o-Phthalic acid, phenol and CBBA are predicted to be several orders of magnitude 

less toxic than acequinocyl.

c. Ecological Incidents

The Ecological Incident Information System or EIIS maintained by the Environmental Fate and Effects 

Division, and the Avian Incident Monitoring System (AIMS) maintained by the American Bird 

Conservancy, were searched on February 26, 2015 and no ecological incidents were recorded resulting 

from the use of acequinocyl.

In addition to the incidents recorded in EIIS and AIMS, additional incidents are reported to the Agency in 

aggregated form. Pesticide registrants report certain types of incidents to the Agency as aggregate 

counts of incidents occurring per product per quarter. Ecological incidents reported in aggregate 

reports include those categorized as ‘minor fish and wildlife’ (W-B), ‘minor plant’ (P-B), and ‘other nontarget’ (ONT) incidents. ‘Other non-target’ incidents include reports of adverse effects to insects and 

other terrestrial invertebrates. For acequinocyl, there have been no reported incident summaries as of 

January 8, 2015.

7. Exposure Pathways of Concern 

EFED's environmental exposure models estimate the potential exposure of plants and animals to 

pesticide residues in aquatic and terrestrial environments based on registered labels including maximum 

acequinocyl application rates and intervals. Some of the aquatic models can also be utilized to estimate 

pesticide residues in drinking water for use in the dietary exposure models. A more detailed description 

of aquatic and terrestrial models can be found at the following website: 

http://www.epa.gov/pesticides/science/models_db.htm. 

The Screening Imbibition Program (SIP v.1.0) is used during the problem formulation phase of

Registration Review to provide an upper-bound estimate of exposure of birds and mammals to 

pesticides through drinking water alone. SIP does not aggregate the drinking water exposure route with 

other exposure routes (i.e., dietary, inhalation, dermal). Due to the lack of an observed toxicological 

effect at all levels, the risk from acequinocyl exposure from drinking water alone is presumed to be low.

SIP readout for acequinocyl is available in Appendix 5

The Screening Tool for Inhalation Risk (STIR v.1.0) is used during the problem formulation phase of 

Registration Review to assess the potential for exposure to birds and mammals through inhalation. The 

exposure pathways that are assessed by this tool include both droplet inhalation and vapor phase 

inhalation. STIR is intended to determine if exposure is likely and not whether or not the potential for 

risk exists. If STIR predicts that exposure is likely, additional inhalation data may be necessary to 

adequately assess risk due to the inhalation exposure pathway. The STIR model predicted that exposure 

if not likely significant. STIR inputs and outputs for acequinocyl are available in Appendix 6. 
17

8. Analysis Plan

a. Stressors of Concern

In order to estimate risks of acequinocyl exposures in aquatic and terrestrial environments, all exposure 

modeling and resulting risk conclusions will be based on registered labels including maximum 

application rates and methods for each use of acequinocyl. EFED's environmental exposure models 

estimate the potential exposure of plants and animals to pesticide residues in aquatic and terrestrial 

environments. 

i. Ecological Risk Assessment

The stressors of concern for terrestrial taxa are acequinocyl and R1. Based on empirically-derived 

toxicity endpoints and predicted toxicity from ECOSAR, acequinocyl and R1 are predicted to be of equal 

toxicity. The stressors of concern for aquatic taxa are acequinocyl, R1, and the degradate AKM-08 which 

forms primarily during aqueous photolysis. Based on chemical similarities, empirically-derived toxicity 

endpoints, and the results of ECOSAR modeling results for aquatic taxa, these chemicals are presumed 

to be equally toxic to aquatic taxa. As in past risk assessments, conservative assumptions may be made 

for modeling aquatic EECs due to uncertainties about the available fate data. Two approaches may be 

used to address the uncertainty by bounding EECs. Approach 1 will assume parent compound stability, 

while Approach 2 (total toxic residues of acequinocyl + R1) will assume that the half-lives of acequinocyl 

and the R1 degradate were accurate. Approach 2 will assume equal toxicity for acequinocyl and R1. 

Approach 2 will not capture exposure to AKM-08 which is proposed as a degradation product of R1 and 

is assumed to be equally as toxic as R1 and acequinocyl. Approach 2 may be updated to include AKM-08 

if it is determined that the available fate data are sufficient to address AKM-08 formation and decline. 

However, Approach 1 will account for any uncertainty in the formation of AKM-08 or any minor 

degradates which have similar structure to acequinocyl4 and may have similar toxicity to acequinocyl 

and R1. 

ii. Drinking Water

The last DWA was conducted in 2011 (DP389520). A new DWA will be conducted in registration review 

for all registered uses of acequinocyl. The DWA will include exposure estimates based on acequinocyl 

and the hydroxylated degradate, that is, R1 (residue of concern recommended by the Metabolism 

Assessment Review Committee (MARC) of the Health Effects Division (HED) (USEPA, 2004c) in surface 

and ground waters.

As in previous DWAs, two approaches may be used to calculate EDWCs due to uncertainties associated 

with the available environmental fate data. In Approach 1, acequinocyl will be conservatively assumed 

to be stable to all routes of degradation. In Approach 2, it will be assumed that the half-lives of 

acequinocyl and the degradation product R1 were accurate and the total toxic residues (acequinocyl + 

R1) will be modeled to address toxicity concerns with both acequinocyl and R1. 

Surface water and ground water concentrations will be modeled using the most up-to-date models and 

guidance at the time of the risk assessment. The DWA will also include a summary of available surface 

and ground water monitoring data.

 

4 Minor degradates with structures similar to acequinocyl formed in some of the available fate studies (e.g., 

aqueous photolysis and aerobic aquatic metabolism)
18

b. Measures of Exposure

EFED will use standard available models to evaluate potential exposures to aquatic and terrestrial 

organisms as described at http://www.epa.gov/pesticides/science/models_db.htm. 

i. Available Monitoring Data

EFED will consider available monitoring data from federal and state agencies or other sources. The 

Agency welcomes submission of monitoring data.

c. Measures of Effect

Ecotoxicity data presented in Tables 3-4 of this problem formulation will be used to calculate risk 

quotients. Any additional information submitted by the registrant or found in the open literature prior

to conducting the risk assessment will also be considered. The open literature studies will be identified 

using EPA’s ECOTOXicology database (ECOTOX5), which employs a literature search engine for locating 

chemical toxicity data for aquatic life, terrestrial plants, and wildlife. 

9. Endangered Species Assessment

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

risks to federally listed threatened and endangered (listed) species from registered uses of pesticides in 

accordance with the Joint Interim Approaches developed to implement the recommendations of the 

April 2013 National Academy of Sciences (NAS) report, Assessing Risks to Endangered and Threatened 

Species from Pesticides. The NAS report outlines recommendations on specific scientific and technical 

issues related to the development of pesticide risk assessments that EPA and the Services must conduct 

in connection with their obligations under the ESA and FIFRA. EPA will address concerns specific to 

acequinocyl in connection with the development of its final registration review decision for acequinocyl. 

In November 2013, EPA, the U.S. Fish and Wildlife Service, National Marine Fisheries (the Services), and 

USDA released a white paper containing a summary of their joint Interim Approaches for assessing risks 

to listed species from pesticides. These Interim Approaches were developed jointly by the agencies in 

response to the NAS recommendations, and reflect a common approach to risk assessment shared by 

the agencies as a way of addressing scientific differences between the EPA and the Services. Details of 

the joint Interim Approaches are contained in the November 1, 2013 white paper, Interim Approaches 

for National-Level Pesticide Endangered Species Act Assessments Based on the Recommendations of the 

National Academy of Sciences April 2013 Report.

Given that the agencies are continuing to develop and work toward implementation of the Interim 

Approaches to assess the potential risks of pesticides to listed species and their designated critical 

habitat, this ecological problem formulation supporting the Preliminary Work Plan for acequinocyl does 

not describe the specific ESA analysis, including effects determinations for specific listed species or 

designated critical habitat, to be conducted during registration review. While the agencies continue to 

develop a common method for ESA analysis, the planned risk assessment for the registration review of 

acequinocyl will describe the level of ESA analysis completed for this particular registration review case. 

This assessment will allow EPA to focus its future evaluations on the types of species where the 

potential for effects exists, once the scientific methods being developed by the agencies have been fully 

vetted. Once the agencies have fully developed and implemented the scientific methods necessary to 

 

5 http://cfpub.epa.gov/ecotox/
19

complete risk assessments for listed species and their designated critical habitats, these methods will be 

applied to subsequent analyses of acequinocyl as part of completing this registration review.

10. Endocrine Disruptors Screening Program 

Acequinocyl was not included in either the first or second group of chemicals issued an order to conduct

Tier I EDSP testing, for more information on the EDSP program, visit http://www.epa.gov/endo/.

11. Preliminary Identification of Data Gaps

a. Fate

Table 7 lists the status of the fate and transport data requirements for acequinocyl. Although fate data 

are available, there are data gaps for all guideline requirements triggered for acequinocyl uses (except 

terrestrial field dissipation) because of the numerous issues with the available studies. These issues 

need to be addressed to upgrade the status of these studies. A common issue identified in most of the 

submitted fate studies is the necessity to determine whether the analytical methods were appropriate 

to accurately assess the rate of degradation of acequinocyl and to identify its major transformation 

products. Validation of all analytical methods used is required to address this issue. Another common 

deficiency is the lack of storage stability data to determine if the degradation of [14C] acequinocyl and its 

transformation products occurred during storage before the analysis of samples. Storage stability data 

reflecting storage conditions for each study are required to address this issue. Although some data have 

been submitted to address these issues (e.g., method validation), they are insufficient to upgrade any of 

the studies.

It would be ideal to collectively address the data gaps for all of the fate studies; however, the ecological 

risk assessment and DWA may proceed based on the available data by making conservative assumptions 

as in past risk assessments. Two approaches may be used to bound aquatic EECs. In Approach 1, 

acequinocyl will conservatively be assumed to be stable to all routes of degradation because of the 

uncertainties associated with the environmental fate data, mainly the lack of validation of the analytical 

methods and the lack of storage stability data. In Approach 2, it will be assumed that the half-lives of 

acequinocyl and the degradation product R1 are accurate and total toxic residues (acequinocyl + R1) will 

be modeled to address toxicity concerns with R1. 

Uncertainties about degradation rates would need to be addressed for all studies in order to move away 

from conservative assumptions such as those outlined above. Addressing other issues such as testing on 

additional soils (e.g. aerobic soil metabolism) is expected to have little impact on the risk assessment 

unless issues with the existing studies surrounding potential overestimation of degradation rates are 

addressed first; thereby, potentially allowing the risk assessment to move away from the assumption of 

stability. Despite uncertainties in the fate data, EECs based on both approaches led to the same 

conclusions in past risk assessments; that is, the greatest risk to the aquatic environment from use of 

acequinocyl is direct effects on aquatic invertebrate species. On the other hand, reliance on potentially 

conservative assumptions may lead to overly conservative mitigation measures to protect endangered 

aquatic species. 
20

Table 7. Environmental Fate Data and Data Gaps for Acequinocyl

OCSPP 

Guideline

Data Requirement MRID Classification

Data 

Gap?

Comments

835.2120 Hydrolysis 45434908 Supplemental Yes It would be ideal to collectively 

address the data gaps for all of the 

fate studies; however, the 

ecological risk assessment and 

DWA may proceed based on the 

available data by making 

conservative assumptions as in 

past risk assessments. 

A detailed discussion about data 

gaps and assumptions that will be 

made in the absence of additional 

data are described above.

835.2240 Aqueous Photolysis 45434909 Supplemental Yes

835.2410 Soil Photolysis 45434910 Supplemental Yes

835.4100

Aerobic Soil 

Metabolism

45434911

45434912

Supplemental 

Invalid Yes

835.4200 Anaerobic Soil 

Metabolism - - Yes

835.4300 Aerobic Aquatic 

Metabolism 45434914 Supplemental Yes

835.4400 Anaerobic Aquatic 

Metabolism 45434913 Supplemental Yes

835.1230

835.1240

Leaching

Adsorption/

Desorption

45531902

45434907

Supplemental

Supplemental Yes

835.6100 Terrestrial Field 

Dissipation 45651601 Acceptable No

850.1730 Accumulation in Fish 45434923 Supplemental Yes

b. Effects

Tables 8-9 identify ecological effect studies by MRID that offer data for each guideline requirement. In 

the case that studies providing valid toxicity endpoints are not available, these will be recommended 

below. Rationale for additional data requests are presented in the table, and in the case that OCSPP test 

guidelines are not available for the data requirement, rationale for the additional data request is present 

in the comments. 

Table 8: Data Gap Table of Aquatic Effect Data for Acequinocyl and Major Degradates

OCSPP 

Guideline

Data requirement MRID Classification Data 

Gap?

Comments

850.1010 Freshwater 

Invertebrate Acute 

Toxicity 

46372101 Acceptable No

850.1035

Mysid

850.1025

Oyster

Estuarine/Marine

Invertebrate 

Oyster Acute 

Toxicity 

45434917

45434916

Supplemental 

Supplemental

Yes Guideline requirement for mysid 

shrimp is fulfilled. Study recorded 

high rate of degradation of the 

chemical throughout the 

experiment, however this recovery 

% is consistent with all aquatic 

studies. 
21

OCSPP 

Guideline

Data requirement MRID Classification Data 

Gap?

Comments

Guideline requirement for mollusk 

remains unfulfilled. Poor 

performance of controls in the 

eastern oyster study (MRID 

45434916) means that this study is 

only valid for qualitative use. 

850.1300 Freshwater 

Invertebrate Life 

Cycle

45434922 Supplemental No The supplemental study is 

considered scientifically sound for 

use in the risk assessment, as the 

low recovery % was outside 

guideline recommendations but was 

consistent with other aquatic 

studies. 

850.1350 Estuarine/Marine

Invertebrate Life 

Cycle

None NA No Waiver request was granted to 

exempt the registrant from this 

guideline requirement because of 

solubility issues with acequinocyl. 

This endpoint will be estimated 

using an Acute to Chronic Ratio 

(ACR). 

850.1075 Freshwater Fish 

Acute Toxicity

45868502/

45434920

(same study)

Trout

45434918

Bluegill

Supplemental

Supplemental

No The supplemental study is 

considered scientifically sound for 

quantitative use in the risk 

assessment as the low chemical 

recovery % was outside guideline 

recommendations but was 

consistent with other aquatic 

studies.

850.1075 Estuarine/Marine 

Fish Acute Toxicity

45434921 Supplemental No The supplemental study is 

considered scientifically sound for 

use in the risk assessment, as this 

limit test measured no effect at 

levels that were several orders of 

magnitude above the limit of 

solubility. The chemical recovery % 

was outside guideline 

recommendations but was 

consistent with other aquatic 

studies. 

850.1400 Freshwater Fish 

Early-Life Stage

45428607 Supplemental Yes Only two replicates per test 

concentration were included. As a 

result, the study may only be used 

to qualitatively assess risk of chronic 

exposure to freshwater fish. Study 
22

OCSPP 

Guideline

Data requirement MRID Classification Data 

Gap?

Comments

must be repeated with the 

recommended four replicates. In the 

absence of these data, chronic 

freshwater fish toxicity data for 

surrogate pesticides – starting with 

data for closely related pesticides 

and proceeding to data for less 

related pesticides – may be used to 

characterize the chronic toxicity of 

acequinocyl to freshwater fish. 

850.1400 Estuarine/Marine

Fish Early-Life 

Stage

None NA Yes In absence of data, chronic toxicity

to estuarine/marine fish may be 

characterized using data for 

surrogate pesticides – starting with 

data for closely related pesticides 

and proceeding to data for less 

related pesticides.

EFED acknowledges that previous 

chronic studies with 

estuarine/marine studies have 

encountered difficulties maintaining 

concentrations due to low solubility 

in salt water. If this problem 

continues to occur, this test can be 

conducted using TEP, as this is 

reported to have a higher solubility 

in salt water. 

850.4400 Aquatic Vascular 

Plant Toxicity Test 

using Lemna spp. 

None NA Yes 40 CFR Part 158 requires the 

submission of aquatic vascular plant 

toxicity data. Risk to this taxa will be 

presumed until data are submitted. 

850.4500 Green Algae

Toxicity

Pseudokirchneriella 

subcapitata

45428611

TGAI

45435008

TEP

Supplemental No Both studies with green algae were 

conducted for less than the 

recommended 96 hours and as a 

result, are classified as 

supplemental. The toxicological 

endpoints derived from these 

studies for green algae are far above 

the limit of solubility of this 

850.4500 Marine diatom

Skeletonema 

costatum

None NA Yes
23

OCSPP 

Guideline

Data requirement MRID Classification Data 

Gap?

Comments

850.4500 Freshwater diatom 

Navicula pelliculosa

None NA Yes chemical, so the submission of a 

new study on green algae would not 

impact the risk conclusion and is 

therefore not requested at this time. 

40 CFR Part 158 requires the 

submission of toxicity data for 

nonvascular aquatic plant species 

Green Algae Pseudokirchneriella 

subcapitata, Marine diatom

Skeletonema costatum,

Freshwater diatom Navicula 

pelliculosa, and Blue Green 

Algae/Cyanobacterium Anabaena 

flos-aquae. Risk to this taxa will be 

presumed until valid studies are 

submitted for each taxa except 

green algae.

850.4550 Blue Green Algae/ 

Cyanobacterium 

Anabaena flosaquae

None NA Yes

Non Guideline Whole sediment: 

chronic 

invertebratesfreshwater and 

estuarine/marine

None NA Yes Chronic sediment invertebrate toxicity 

data are required under 40 CFR Part 158 

and further clarified in Guidance for 

Benthic Invertebrates (USEPA, 2014) if: 

i. The half-life of the pesticide in 

sediment if > 10 days in either 

the aerobic soil or aquatic 

metabolism studies and if any of 

the following exist:

A. The soil partition coefficient 

(Kd) is ≥ 50

B. The log Kow is ≥ 3.

C. The Koc is ≥ 1,000.

The average half-life of acequinocyl and 

major degradate R1 reported in the 

aerobic soil metabolism is 42 days; and 

the log Kow and Koc of acequinocyl are 

6.69 and 1027-970 mL/g, respectively.

Exposure duration for benthic 

invertebrates to acequinocyl and R1 is 

considered more relevant because 

available data suggest that the toxicity 

of the two compounds is equal for 

aquatic invertebrates.

Therefore, chronic sediment tests with 

the midge Chironomus dilutus, 

freshwater amphipod Hyalella azteca, 
24

OCSPP 

Guideline

Data requirement MRID Classification Data 

Gap?

Comments

and estuarine/marine amphipod 

Leptocheirus plumulosus are needed. 

In the absence of these data, sedimentdwelling invertebrate chronic toxicity 

data for surrogate pesticides – starting 

with data for closely related pesticides 

and proceeding to data for less related 

pesticides – may be used to characterize 

the chronic toxicity of acequinocyl to 

sediment-dwelling invertebrates.

As indicated in 40 CFR Part 158, the 

registrant is required to submit a 

protocol for approval prior to initiating 

the study.

Table 9: Data Gap Table of Terrestrial Effects Data for Acequinocyl 

OCSPP 

Guideline

Data requirement Submitted 

Studies

(MRID)

Study 

Classifications

Data 

Gap?

Comments

850.2100 Avian Acute Oral 

Toxicity (Upland 

game or waterfowl 

species)

45660601 Acceptable No --

850.2100 Avian Acute Oral 

Toxicity (Passerine 

species)

None NA Yes Measures of effect from a nonpasserine species could potentially 

underestimate acequinocyl toxicity 

to passerine species, consequently, 

additional information on 

acequinocyl toxicity to a passerine 

species is needed to reduce the 

uncertainty created by this analysis.

850.2200 Avian Dietary 

Toxicity

46622701

45435003

Acceptable

Acceptable

No --

850.2300 Avian

Reproduction

45435005

45435006 

Acceptable

Acceptable

No --

850.3020 Tier I- Honeybee 

Acute Adult 

Contact Toxicity

45435007 Acceptable No --

NonGuideline

(OECD 213)

Tier I- Honeybee 

Acute Adult Oral 

Toxicity

45428608 Supplemental No The supplemental study is 

considered scientifically sound for 

use in the risk assessment.

NonGuidelineTier I-Honeybee 

Adult Chronic Oral 

Exposure

None NA Yes This study estimates the exposure to 

adult bees resulting from visits to 

contaminated flowers over an 
25

OCSPP 

Guideline

Data requirement Submitted 

Studies

(MRID)

Study 

Classifications

Data 

Gap?

Comments

extended period of time or through 

consumption of contaminated food 

in the hive. 

NonGuidelineTier I- Honeybee 

Larval Acute and 

Chronic Oral 

Exposure 

None NA Yes These studies help characterize the 

effect of repeated exposure of the 

brood to pesticides that may enter 

the hive and be stored in food 

sources such as pollen, honey, royal 

or brood jelly.

850.3030 Tier II- Honeybee 

Toxicity of Residues

on Foliage

None NA No The acute contact 48-hr LD50 was 

above 100 μg ai/bee. This study is 

only triggered if contact toxicity is 

less than 11 μg ai/bee. 

NonGuidelineTier II- Nectar and 

Pollen Residue 

Study for Insect 

Pollinators

(none) NA Yes If risks are identified from Tier I risk 

estimation for honeybees, then Tier 

II risk estimations may need to be 

called in to identify more targeted 

routes of exposure. Exposure of 

acequinocyl through translocation 

to nectar and pollen could be a 

route of exposure to insect 

pollinators. 

NonGuideline

(OECD 75)

Tier II- Semi-Field 

Testing for 

Honeybees

None NA Yes If risks are identified from Tier I risk 

estimation for honeybees, then Tier 

II risk estimations may need to be 

called in to identify more targeted 

risk mitigation options. Typically

semi-field studies are usually 

conducted under conditions that 

represent the worst-case exposure 

scenario of proposed uses to the 

entire colony. 

850.3040 Tier III- Field 

Testing for 

Pollinators

None NA Yes If risks are identified from Tier II risk 

estimation for honeybees, then Tier 

III field studies may need to be 

called in to identify more targeted 

risk mitigation options.

850.4100 Seedling 

Emergence and 

Seedling Growth 

45428609 Acceptable No --

850.4150 Vegetative Vigor 45428610 Acceptable No

Justifications for non-guideline data requirements are below: 
26

Study Title: Tier I- Pollinator Chronic Oral Toxicity, Adult

Rationale for Requiring the Data

Terrestrial invertebrates are likely to be impacted if exposed to pesticides in various use settings. Pesticide 

residues may be transferred to pollen and/or nectar of treated plants and subsequently brought back to the 

hive. Therefore, potential chronic effects to adult honeybees and other pollinators from oral exposure to 

some pesticides could exist. Currently available toxicity studies do not address possible lethal and sublethal 

effects of chronic oral exposure on adult terrestrial invertebrates and will assist in determining whether the 

sensitivity of adult bees differs from that of earlier life stages. Because of the potential for pollen and 

nectar to be contaminated with pesticide residues, and subsequently brought back to the hive, it is 

important to determine the chronic oral toxicity of this compound to adult honeybees and other pollinators.

The Office of Pesticide Programs has made available a guidance regarding ecological testing for 

invertebrates with the honeybee. The guidance discusses Tier I laboratory-based chronic oral toxicity 

studies of individual adult honeybees as a critical component of the screening-level risk assessment process 

for examining potential risks from specific routes of exposure. The guidance can be found at: 

http://www2.epa.gov/pollinator-protection/pollinator-risk-assessment-guidance . Study design elements 

for the chronic 10-day oral toxicity test with honeybees are similar to the OECD Test Guideline 213 acute 

oral toxicity test http://www.oecd-ilibrary.org/environment/test-no-213-honeybees-acute-oral-toxicitytest_9789264070165-en .

Practical Utility of the Data

How will the data be used?

The Tier I chronic oral toxicity data on adult bees serve as a foundation for the screening-level assessment 

of potential risk to non-target organisms including federally listed threatened or endangered species and 

non-listed terrestrial invertebrate insects, including pollinators, from chronic oral exposures to pesticides. 

The data will be used to reduce uncertainties associated with the risk assessment for terrestrial 

invertebrates and will improve EPA’s understanding of the potential direct and indirect lethal and sublethal 

effects on a broad range of terrestrial species, particularly insect pollinators and to determine whether 

adult toxicity differs substantially from other life stages evaluated in other Tier I tests. If chronic oral effects 

data for adults are not available, risks to terrestrial insects from chronic oral exposure will be assumed.

How could the data impact the Agency’s future decision-making?

The data will inform the determination required under FIFRA or the ESA as to whether continued 

registration of a pesticide is likely to result in unreasonable adverse effects to non-target species or is likely 

to adversely affect listed threatened or endangered species and/or their designated critical habitat. 

Without these data, EPA may need to presume risk which will limit the flexibility of pesticide products to 

comply with FIFRA and the ESA, and could result in use restrictions. 

Study Title: Tier I- Pollinator Acute Oral Toxicity, Larvae

Rationale for Requiring the Data

Terrestrial invertebrates are likely to be impacted if exposed to pesticides in various use settings. Pesticide 

residues may be transferred to pollen and/or nectar of treated plants and subsequently brought back to the 

hive where larvae and pupae may be exposed. Therefore, potential adverse effects to developing bees and 

other insect pollinators could result from exposure to pesticide residues. Available toxicity studies do not 

address possible effects on brood (larvae and pupae) survival/development. Because of the potential for 

pollen and nectar to be contaminated with pesticide residues, and subsequently brought back to the hive, it 

is important to determine the acute oral toxicity of this compound to bee brood. 
27

The Office of Pesticide Programs has made available a guidance regarding ecological testing for terrestrial 

invertebrates using the honeybee as a surrogate test species. The guidance discusses Tier I laboratorybased acute toxicity studies of individual honeybee larvae as a critical component of the screening-level risk 

assessment process for examining potential risks from specific routes of exposure. The guidance can be 

found at: http://www2.epa.gov/pollinator-protection/pollinator-risk-assessment-guidance . Additional 

guidance on larval honeybee toxicity test design can be found in OECD Test Guideline 237 

http://www.oecd-ilibrary.org/environment/test-no-237-honey-bee-apis-mellifera-larval-toxicity-test-singleexposure_9789264203723-en .

Practical Utility of the Data

How will the data be used?

The Tier I acute oral toxicity data on honeybee larvae serve as a foundation for the screening-level 

assessment of potential risk to non-target organisms such as federally listed threatened or endangered and 

non-listed terrestrial invertebrate insects, including pollinators, and/or modify their designated critical 

habitat from acute oral exposures to pesticides. The data will be used to reduce uncertainties associated 

with the risk assessment for terrestrial invertebrates and will improve EPA’s understanding of the potential 

effects on terrestrial species and whether there is a differential sensitivity of larval bees relative to adult 

bees. If acute oral effects data for larvae are not available, risks to terrestrial insects from acute oral 

exposure will be assumed

How could the data impact the Agency’s future decision-making?

The data will inform the determination required under FIFRA or the ESA as to whether continued 

registration of a pesticide is likely to result in unreasonable adverse effects to non-target species or is likely 

to adversely affect listed threatened or endangered species and/or modify their designated critical habitat. 

Without these data, EPA may need to presume risk which will limit the flexibility of pesticide products to 

comply with FIFRA and the ESA, and could result in use restrictions. 

Study Title: Tier I- Pollinator Chronic Oral Toxicity, Larvae

Rationale for Requiring the Data

Terrestrial invertebrates are likely to be impacted if exposed to pesticides in various use settings. Pesticide 

residues may be transferred to pollen and/or nectar of treated plants and subsequently brought back to the

hive where larvae and pupae may be exposed. Therefore, potential effects to developing bees could result 

from chronic oral exposure to pesticide residues. Available toxicity studies do not address possible chronic 

effects on brood (larvae and pupae) survival. Because of the potential for pollen and nectar to be 

contaminated with pesticide residues, and subsequently brought back to the hive, it is important to 

determine chronic larval/pupal toxicity and whether adult emergence is adversely affected. This study will 

provide information on whether honeybee larvae differ in sensitivity from adult bees following chronic 

exposure. 

The Office of Pesticide Programs has made available a guidance regarding ecological testing for 

invertebrates with the honeybee. The guidance discusses Tier 1 laboratory-based chronic oral toxicity 

studies of individual honeybee larvae as a critical component of the screening-level risk assessment process 

for examining potential risks from specific routes of exposure. The guidance can be found at: 

http://www2.epa.gov/pollinator-protection/pollinator-risk-assessment-guidance.

Additional information on larval honeybee toxicity repeat exposure test design can be found in the oECD 

draft guidance 

http://www.oecd.org/env/ehs/testing/Draft_GD_honeybees_rep_exp_for_2nd_CR_25_November_2013.p

df .
28

Practical Utility of the Data

How will the data be used?

The Tier I chronic oral toxicity data on bee larvae serve as a foundation for the screening-level assessment 

of potential risk to non-target organisms including federally listed threatened or endangered and non-listed 

terrestrial invertebrate insects, including pollinators, from chronic oral exposures to pesticides. The data 

will be used to reduce uncertainties associated with the risk assessment for terrestrial invertebrates and 

will improve EPA’s understanding of the potential direct and indirect lethal and sublethal effects on a broad 

range of terrestrial species, particularly insect pollinators. These data will also assist in determining 

whether early life stages of the bee differ in their sensitivity to pesticides relative to adults. If chronic oral 

effects data for larvae are not available, risks to terrestrial insects from chronic oral exposure will be 

assumed.

How could the data impact the Agency’s future decision-making?

The data will inform the determination required under FIFRA or the ESA as to whether continued 

registration of a pesticide is likely to result in unreasonable adverse effects to non-target species or is likely 

to adversely affect listed threatened or endangered species and/or modify their designated critical habitat. 

Without these data, EPA may need to presume risk which will limit the flexibility of pesticide products to 

comply with FIFRA and the ESA, and could result in use restrictions. 

Study Title: Tier II Semi-Field Toxicity Testing (tunnel/enclosure studies)

Rationale for Requiring the Data

Tier II studies are conditional on the outcome of the screening-level assessment where acute and/or chronic 

risk levels of concern have been exceeded for terrestrial invertebrates. Terrestrial invertebrates are likely to 

be impacted if exposed to pesticides in various use settings. Pesticide residues may be transferred to pollen 

and/or nectar of treated plants and subsequently brought back to the hive and may adversely affect 

developing brood (egg, larvae, and pupae) and adult bees. Screening-level (Tier I) studies of individual bees 

do not address possible effects and/or exposure to pesticide residues at the colony-level. Because of the 

potential for pollen and nectar to be contaminated with pesticide residues, and subsequently brought back 

to the hive, it is important to determine whether bee colonies may be negatively affected under relatively 

controlled exposure conditions of a semi-field study. In addition to providing effects data, these studies can 

provide data on exposure as pesticide residues in pollen/nectar of treated plants.

The Office of Pesticide Programs has made available a guidance regarding ecological testing for 

invertebrates with the honeybee. The guidance describes the tiered testing process and can be found at: 

http://www2.epa.gov/pollinator-protection/pollinator-risk-assessment-guidance . Additional information 

on honeybee colony studies under semi-field conditions can be found in the OECD Guidance 75 

http://www.oecd.org/officialdocuments/publicdisplaydocumentpdf/?cote=env/jm/mono%28 . 

Practical Utility of the Data

How will the data be used? 

Tier II colony-level data will be used to assess potential risk to non-target organisms including listed and 

non-listed terrestrial social invertebrate species and to determine whether effects observed in the 

screening-level (Tier I) laboratory-based studies of individual bees are evident in colony-level studies under 

semi-field conditions. The Tier II semi-field test of whole colonies is a relatively controlled study, i.e., bees 

are confined to a specific area, that is designed to represent potential field-level exposure and account for 

hive dynamics, which are not achievable from other pollinator studies. This study will be used to determine 

whether adverse effects to insect pollinators at the whole colony level, may result for the use of pesticides 

and will help to refine risk estimates derived in the screening-level risk assessment for beneficial terrestrial 
29

invertebrates. Measured residues in pollen/nectar can also be used to refine risk estimates derived from 

model-based or default values in the screening-level assessment.

How could the data impact the Agency’s future decision-making?

The data will inform the determination required under FIFRA or the ESA as to whether continued 

registration of a pesticide is likely to result in unreasonable adverse effects to non-target species or is likely 

to adversely affect federally listed threatened or endangered species or their designated critical habitat. 

Without these data, EPA may need to presume risk which will limit the flexibility of pesticide products to 

comply with FIFRA and the ESA, and could result in significant use restrictions.

Study Title: Tier II Semi-Field Toxicity Testing (feeding studies)

Rationale for Requiring the Data

Pesticide residues may be transferred to pollen and/or nectar of treated plants and subsequently brought 

back to the hive, and may adversely affect developing brood (egg, larvae, and pupae) and adult bees. Tier II 

feeding studies are conditional on the outcome of the screening-level assessment where acute and/or 

chronic risk levels of concern have been exceeded for terrestrial invertebrates based on Tier I studies of 

individual bees. Feeding studies utilize free foraging bee colonies that are “dosed” with specific quantities of 

test material and represent a means of ensuring exposure to the test material through spiked pollen and/or 

sugar solutions fed to the colony while still allowing the bees to forage freely. Since bee colonies are not 

confined to enclosures, colonies can be exposed for longer duration periods without subjecting the bees to 

stress that typically results from Tier II tunnel studies. Available toxicity studies of individual bees (Tier 1) 

conducted to support screening-level assessments do not address possible effects and/or exposure to 

pesticide residues at the colony-level. Because of the potential for pollen and nectar to be contaminated 

with pesticide residues, and subsequently brought back to the hive, it is important to determine whether 

bee colonies may be negatively affected where bees are free foraging and have the option to 

collect/consume alternative forage items beyond the spiked food. Since multiple dose levels can be more 

readily tested, feeding studies can help to define dose-response relationships at the whole colony level.

The Office of Pesticide Programs has made available a guidance regarding ecological testing for invertebrates 

with the honeybee. The guidance describes the tiered testing process and can be found at: 

http://www2.epa.gov/pollinator-protection/pollinator-risk-assessment-guidance . Additional information on 

honeybee colony feeding studies can be found in the EPPO Guidance 170 at: 

http://www.nationalbeeunit.com/index.cfm?pageId=187 .

Practical Utility of the Data

How will the data be used?

Tier II colony feeding data will be used to assess potential risk to non-target organisms including listed and 

non-listed terrestrial social invertebrate species. The colony feeding study is designed to represent 

potential field-level exposure and account for hive dynamics using longer duration exposure periods than 

are possible in Tier II tunnel studies. The study will be used to determine whether potential adverse effects 

to insect pollinators at the whole colony level when bees are able to forage naturally beyond the spiked 

food. Results from the feeding study will help to refine the screening-level risk assessment for beneficial 

terrestrial invertebrates that were based on Tier I studies on individual bees. Since feeding studies can help 

to define a dose-response relationship at the colony level, the studies can provide a means of determining 

exposure thresholds below which the likelihood of adverse effects on colonies may be low.

How could the data impact the Agency’s future decision-making?
30

Tier II colony-level data will be used to refine screening-level risk estimates derived using Tier I laboratorybased data on individual bees. The Tier II data will inform the determination required under FIFRA or the 

ESA as to whether continued registration of a pesticide is likely to result in unreasonable adverse effects to 

non-target species or is likely to adversely affect federally listed threatened or endangered species or their 

designated critical habitat. Without these data, EPA may need to presume risk which will limit the flexibility 

of pesticide products to comply with FIFRA and the ESA, and could result in significant use restrictions.

Study Title: Residues in Pollen and Nectar

Rationale for Requiring the Data

Terrestrial invertebrates are likely to be impacted if exposed to pesticide residues in various use settings. 

Pesticide residues may be transferred to pollen and/or nectar of treated plants and subsequently brought 

back to hive where all life stages may be exposed. For some pesticides, the quantification of pollinatorrelevant residues in treated flowering plants is needed, since pollinators will be exposed to residues from 

either current or prior season applications (due to the potential for residues to accumulate in plants and 

trees). Residues in edible/transportable-to-hive parts of treated trees and plants, including (where 

appropriate), but not limited to, guttation water, sap/resins, whole plant tissue (e.g., leaves, stems), as well 

as blooming, pollen-shedding, and nectar producing parts (i.e., flowers and, if present, extra-floral nectaries) 

of plants may inform the potential for risk. Studies should be designed to provide residue data for crops 

and application methods of concern.

The Office of Pesticide Programs has made available a guidance regarding ecological testing for 

invertebrates with the honeybee. The guidance can be found at: http://www2.epa.gov/pollinatorprotection/pollinator-risk-assessment-guidance .

Practical Utility of the Data

How will the data be used?

Measured residue data will be used to refine conservative estimates of pesticide exposure and reduce 

uncertainties associated with the Tier I exposure assessment by providing direct measurements of pesticide 

concentrations resulting from actual use settings. Measured residues may provide a more realistic 

understanding of exposure through contact or ingestion with which to calculate risk quotients for individual

bees as well as to characterize exposure to the colony. If measured residue data are not available, risk 

estimates for terrestrial insects will be based on model-generated or default values used to support the 

screening-level assessment.

How could the data impact the Agency’s future decision-making?

The data will inform the determination required under FIFRA or the ESA as to whether continued 

registration of a pesticide is likely to result in unreasonable adverse effects to non-target species or is likely 

to adversely affect federally listed threatened or endangered species or their designated critical habitat. 

Without these data, EPA will have to rely on conservative estimates of exposure which will limit the 

flexibility of pesticide products to comply with FIFRA and the ESA, and could result in use restrictions. 
31
32

12. Bibliography

USEPA. 2004a. Overview of the Ecological Risk Assessment Process in the Office of Pesticide Programs. 

U.S. Environmental Protection Agency, Office of Prevention, Pesticides and Toxic Substances, 

Office of Pesticide Programs, Washington DC. January 23, 2004.

USEPA 2004b. Section 3 Request for Uses of Acequinocyl (PC code 006329) on Pome Fruit, Citrus, 

Almonds, Pistachios, Strawberries, and Outdoor Ornamentals. February 3, 2004. DP 285811, 

286428, 289153, 290010, 287269, 290009, 291174

USEPA, 2004c. Acequinocyl. Report of the Metabolism Assessment Review Committee (MARC). 

Meeting Date: December 17, 2003. Memo dated January 7, 2004. TRX 0052294

USEPA, 2010. Review of study of stability of acequinocyl in solvent and seawater and decision regarding 

data requirement for mysid reproduction study. U.S. Environmental Protection Agency, Office of 

Prevention, Pesticides and Toxic Substances, Office of Pesticide Programs, Washington DC. 

August 10, 2010. D368576.

USEPA, 2011. Acequinocyl: Drinking Water Assessment to Support Proposed New IR-4 Uses (Succulent 

Soybean Vegetable, Low Growing Berry, Small Fruit Vine Climbing -Except Fuzzy Kiwifruit, 

Succulent Shelled Beans, Cowpea Forage, Caneberry, Melon, Cucumber, and Cherry). 

DP389520.

USEPA. 2014a. Acequinocyl (006329): Screening Level Usage Analysis (SLUA). Biological and Economic 

Analysis Division, Office of Pesticide Programs. November 10, 2014.

USEPA, 2014b. Toxicity Testing and Ecological Risk Assessment Guidance for Benthic Invertebrates. 

USEPA Office of Chemical Safety and Pollution Prevention, Office of Pesticide Programs. April 9, 

2014.
33

Appendix 1: Previous Actions and Assessed Uses for Acequinocyl

Crop Application Rate (lb ai/A) Number of 

Applications 

(Application 

Interval in Days)

Action/DP Barcode/Date

Single

Lbs a.i./A

Seasonal/ 

Annual

Lbs a.i./A

Succulent Soybean, Low Growing 

Berry, Small Fruit Vine Climbing 

(except kiwifruit), succulent 

shelled beans, cowpea forage, 

Caneberry, Melon, Cucumber, 

and Cherry

0.3 0.6 2 (14-21) IR-4 New Uses 

D389520, D390259

10/25/2011

Tier II Drinking Water 

Assessment

D448205

9/7/2011

Fruiting Vegetables,

Okra,

Edible podded beans,

Hop

0.3 0.6 2 (21) IR-4 

New Uses Registration/

Drinking Water Assessment

D368579, D368426, 

D417967, D417966

4/29/2010 

Citrus,

Tree Nuts,

Grapes,

Pome Fruits,

Strawberries

0.3 0.6 2 (21)

Outdoor Ornamental 0.125 0.25 2 (14)

Citrus,

Tree Nuts,

Grapes,

Pome Fruits

0.3 0.6 2 (21) Section 3 

New Uses

D337381, D330467, 

D330471

Non-food outdoor uses (various 8/15/2007

ornamentals)

0.125 0.6 5 (14)

Food Crops (citrus, tree nuts, 

grapes, pome fruits, 

strawberries)

0.3 0.6 2 (21) Tier II Drinking Water 

Assessment

DP337221

Outdoor Residential 6/27/2007

Ornamentals (including roses)

0.125 0.625 5 (14)

Pome Fruits

Citrus

Almonds

Pistachios

Strawberries

0.3 0.6 2 (21) Section 3

New Uses

D285811, D286428, 

D289153, D290010, 

D287269, D290009, 

D291174

2/3/2004

Outdoor Ornamentals 0.125 0.250 2 (14)

Greenhouse, Shade House

Ornamental,

Floral,

Foliage,

Nursery Crops

0.125 

lbs/100 

gallons 

formulation

N/A N/A Section 3 

New Uses

D291707

8/7/2003
34

Appendix 2: Application Rates of Acequinocyl on Agricultural Crops (Based on Kanemite 15 SC Label).

Use Max single app 

rate (lbs./A)

Max # apps per 

year

Max app rate per 

year (lbs ai/A)

Minimum 

retreatment 

interval (days)

Tree Nuts and Pistachios 31 fl oz/A1 2 0.6 21

Citrus 31 fl oz/A 2 0.6 21

Small-Vine subgroup 13-07F 

(Except Kiwi) 31 fl oz/A 2 0.6 21

Pome Fruits 31 fl oz/A 2 0.6 21

Low-Growing BerriesSubgroup 13-07G

31 fl oz/A 2 0.6 21

Fruiting Vegetables (Except 

cucurbits) 31 fl oz/A 2 0.6 21

Melon Crop Group 9A and 

Cucumber 31 fl oz/A 2 0.6 21

Succulent Shelled Bean 31 fl oz/A 2 0.6 14

Caneberry Crop Subgroup 13-

07A

31 fl oz/A 2 0.6 21

Cherry 31 fl oz/A 2 0.6 14

Okra 31 fl oz/A 2 0.6 21

Edible Potted Beans 31 fl oz/A 2 0.6 21

Succulent Soy Vegetable 31 fl oz/A 2 0.6 21

Hops 31 fl oz/A 2 0.6 21

Landscape Ornamentals 12.8 fl oz/A 2

2 0.25 14

1

Label states that Kanemite contains 1.25 lb ai/gal

2

Inferred based on maximum single and annual application rates. 
35

Appendix 3. Summary of Acequinocyl Major Degradates and Maximum Percent Formation Observed in the Laboratory and Field Studies

Degradate 

Maximum Degradate Concentration (% of applied) and Time to Max Concentration

Hydrolysis1 Aqueous 

Photolysis

Soil 

Photolysis4

Aerobic Soil 

Metabolism

Aerobic 

Aquatic 

Metabolism5

Anaerobic 

Aquatic 

Metabolism5

Terrestrial Field 

Dissipation

R1 (2-dodecyl-3-hydroxy1,4-naphthalenedione) 

pH 7: 

54.7% (96 hr) --

2

--

Silt loam soil; 

phenyl-U14C 

label:

33.8% (2 days)

Total system: 

12.2% (0 days)

Total system: 

41.0-41.1% (3, 7, 

and 14 days)

NY: 37.8% (3 hr 

after 2nd

application)

GA: 37.8%7

CA: 26.4%7

AKM 18 [2-(1,2-

dioxotetradecyl)benzoic 

acid]

pH 9: 

10.9% (3 hr) -- --4

--

Total system: 

19.5% (1 day)

Total system: 

23.2% (269 days) NY: 16.5% 7,8

AKM-08 [2-(2-oxo-dodecyl)-

3-hydroxy-1,4-

naphthoquinone]

--

Buffer solution:

12.9% (2 hr)

-- -- -- -- --

O

O

CH2(CH2)10CH3

OH
36

Degradate 

Maximum Degradate Concentration (% of applied) and Time to Max Concentration

Hydrolysis1 Aqueous 

Photolysis

Soil 

Photolysis4

Aerobic Soil 

Metabolism

Aerobic 

Aquatic 

Metabolism5

Anaerobic 

Aquatic 

Metabolism5

Terrestrial Field 

Dissipation

o-Phthalic acid

--

Buffer solution:

12.7% (24 hr)3

River water:

11.9% (24 hr)3

-- -- -- -- --

Phenol

--

River water:

10% (24 hr)3

-- -- -- -- --

CBAA (2-carboxy-α-oxobenzene acetic acid)

-- -- -- --

Water layer:

11.3% (2 days)6

-- --

1 “Unknown 1” was described as polar radioactive material consisting of one or more compounds. It was observed at pH 1.2, 4, 7, and 9 and represented a maximum of 41.6% of 

the applied radioactivity (pH 9, 0.75 hours).

2 Although a maximum of 11.61% formed in the irradiated sample, formation can be predominately attributed to hydrolysis (9.07% formation in the dark control).

3 There is uncertainty about the % formation. Detected in the aqueous eluate fraction which was only analyzed for the irradiated samples at 24 hours. Aqueous eluate fraction was 

40.53% (buffer solution) and 43.90% (river water) for the irradiated samples and < 5.08% (buffer solution) and < 5.19% (river water) for the dark samples at 24 hours. Unknown if 

present in dark samples but must be less the ca. 5% of applied radioactivity in those samples. Only a portion of the aqueous eluate fraction was analyzed (60% of the buffer solution 

and 87% of the river water fraction applied to the column) due to loss during purification.

4 AKM-18 and compound A (unidentified) formed greater than 10% in the irradiated samples; however, an equal or greater amount formed in the dark controls indicating that 

formation was not due to photolysis. Likewise, radioactive material designated as polar compounds was observed greater than 10% of the applied radioactivity (26.2% irradiated 

samples and 23.4% dark controls). However, it is uncertain if the irradiated polar peak represented photolytic degradation because the polar peaks may have represented more 

than one compound and those compounds may or may not have been present in both irradiated samples and dark controls.

5 Degradates retaining the naphthoquinone structure formed less than 10% of applied acequinocyl.

6 Sediment layer was not analyzed.

7 Formed immediately after application.

8 Formation based on a single replicate. The second replicate had a concentration below the LOD and the third replicate was not analyzed due to a lab error.
37

Appendix 4: Complete List of Toxicity Endpoints for Acequinocyl

Taxa Study Type % ai Species Toxicity Value & 

Category

MRID & Status Endpoints 

Affected

Mammals

Acute oral 

870.1100

96.8 Rat 

Rattus norvegicus

LD50> 5000 mg/kg-bw

(Males and Females)

Practically nontoxic

45435011

Acceptable

None

Chronic 

Two 

Generation 

Reproductive 

Study

870.3800

97.1 Rat 

Rattus norvegicus

Male NOAEC= 100 

mg/kg-diet

Male LOAEC= 800 

mg/kg-diet

Female NOAEC> 1500 

mg/kg-diet 

45531909

Acceptable

None

Acute 

Inhalation

870.1300

96.5 Rat 

Rattus norvegicus

LC50> 0.84 mg/L

Males and Females

Slightly Toxic

45435013

Acceptable

Mortality

Birds

Acute Oral

850.2100

97.1 Japanese Quail

Coturnix coturnix 

japonica

8-Day LD50> 2000 

mg/kg-bw

8-day NOAEL= 2000 

mg/kg-bw

Practically nontoxic

45435002

SupplementalJapanese quail 

not a 

recommended 

species. May 

be used for 

quantitative 

assessment of 

risk.

No Effect

Acute Oral

850.2100

98.4 Mallard Duck 

Anas platyrhynchos

LD50> 2000 mg ai/kgbw

NOAEL= 2000 mg ai/kgbw

Practically nontoxic

48660601

Acceptable

None

Acute Oral

850.2100

15.6 Northern Bobwhite 

Quail

Colinus virginianus

8-Day LC50> 2000 

mg/kg-bw

8-Day NOAEL= 2000 

mg/kg-bw

Practically nontoxic 

45530602

Acceptable

No Effect

Acute Dietary

850.2200

97.1 Japanese Quail

Coturnix coturnix 

japonica

8-Day LC50> 4952 

mg/kg-diet

NOAEC= 926 mg/kgdiet 

Slightly toxic

45435004

SupplementalJapanese Quail 

not 

recommended 

test species. 

May be used 

for quantitative 

Subacute 

toxicity= 

NOAEC based 

on weight loss
38

Taxa Study Type % ai Species Toxicity Value & 

Category

MRID & Status Endpoints 

Affected

assessment of 

risk.

Acute Dietary

850.2200

15.6 Northern Bobwhite 

Quail

Colinus virginianus

LC50> 5970 mg ai/kg 

diet

NOAEC= 5970 mg ai/kg 

diet

Practically nontoxic

46622701

Acceptable

None

Acute Dietary

850.2200

97.1 Mallard Duck 

Anas platyrhynchos

LC50> 5000 mg/kg-diet

NOAEC= 488 mg/kg 

diet

Practically nontoxic

45435003

Acceptable

Body Weight 

Gain

Chronic 

(reproduction)

850.2300

97.1 Northern Bobwhite 

Quail

Colinus virginianus

NOAEC= 2515 mg/kg 

ai-diet

LOAEC> 2515 mg/kg aidiet

45435006 

Acceptable

None

Chronic 

(reproduction)

850.2300

97.1 Mallard Duck 

Anas platyrhynchos

NOAEC= 100 mg/kgdiet 

LOAEC= 500 mg/kg-diet

45435005

Acceptable

Female body 

Weight gainno mortality

Freshwater 

Fish

Acute 

850.1075

97.1 Rainbow Trout

Oncorhynchus 

mykiss

LC50> 33 mg ai/L

NOAEC= 33 mg ai/L

Slightly Toxic

45434920 and

45868502-

Supplemental

Recurring 

solubility issues 

led to 

questions 

about the 

exposure 

concentrations. 

As this study 

tested well 

above the 

solubility limit 

(>1000x) and 

saw no effect, 

this is 

satisfactory to 

fulfill guideline 

requirements 

for an acute 

study. 

Endpoints are 

valid for 

None
39

Taxa Study Type % ai Species Toxicity Value & 

Category

MRID & Status Endpoints 

Affected

quantitative 

risk assessment

Acute 

850.1075

15.4 Rainbow Trout

Oncorhynchus 

mykiss

45530601

Invalid 

(formerly 

Acceptable)2

Mortality

Acute 

850.1075

97.1 Bluegill Sunfish

Lepomis 

macrochirus

LC50> 1.1 mg ai/L

NOAEC= 1.1 mg ai/L

Moderately toxic

45434918

SupplementalConducted as a 

limit test. No 

effect was 

observed at 

concentrations 

far greater 

than solubility 

limit. As a 

result, 

endpoints are 

valid to 

quantitatively 

assess risk.

None

Acute 

850.1075

15.8 Bluegill Sunfish

Lepomis 

macrochirus

45428605

Supplemental

(Formerly 

Acceptable)

2

None

Acute 

850.1075

97.1 Zebrafish

Brachydanio rerio

LC50> 1.1 mg ai/L

NOAEC= 1.1 mg ai/L

45434919

SupplementalNot an 

acceptable 

species. 

Endpoints may 

only be used 

for quantitative

risk analysis. 

None

Chronic 

850.1400

15.8 Rainbow Trout

Oncorhynchus 

mykiss

NOAEC= 0.52 mg ai/L 

(

1Centrifuged NOAEC= 

0.07 mg ai/L)

LOAEC= 1.1 mg ai/L 

45428607

SupplementalOnly two

replicates per 

test 

concentration.

Endpoints are 

may only be 

used to 

qualitatively 

Post Hatch

Survival
40

Taxa Study Type % ai Species Toxicity Value & 

Category

MRID & Status Endpoints 

Affected

characterize 

risk. 

Freshwater 

Invertebrates

Acute

850.1010

98.3 Water Flea Daphnia 

magna

LC50= 2.7 μg ai/L

NOAEC= 0.66 μg ai/L

Very highly Toxic

46372101

Acceptable

Mortality and 

sublethal 

effects 

(lethargy)

Acute

850.1010

15.4 Midge

Chironomus riparius

LC50 >13.23 mg a.i./L

*Endpoint reported in 

study did not correct 

for % a.i. The endpoint 

reflected above reflects 

the corrected 

concentration. An 

addendum will be 

issued to correct this in 

the DER.

Slightly Toxic

45782303

SupplementalConcentrations 

not analyzed at 

all 

concentrations

- Endpoints 

may be used to 

quantitatively 

assess risk to 

midges from 

exposure in 

water column.

Mortality 

Chronic

850.1300

98.3 Water Flea Daphnia 

magna

NOAEC= 0.98 μg ai/L

LOAEC= 1.8 μg ai/L

45434922

SupplementalQuick 

degradation of 

technical 

meant low 

recovery rate 

(37-41%). 

Endpoints valid 

for quantitative

assessment or 

risk.

Number of 

young, length 

and dry 

weight

Estuarine/ 

Marine Fish

Acute 

850.1075

97.1 Sheepshead 

minnow Cyprinodon 

variegatus

LC50> 0.19 mg ai/L

NOAEC= 0.19 mg ai/L

(Toxicity endpoints of 

centrifuged samples 

with mean measured 

concentrations) 

Highly Toxic

45434921

SupplementalLimit testPrecipitate 

centrifuged 

and counted in

toxicity 

endpoints 

calculation. No 

effect was

observed at 

concentrations 

far exceeding 

the solubility 

None
41

Taxa Study Type % ai Species Toxicity Value & 

Category

MRID & Status Endpoints 

Affected

limit of this 

chemical. 

Therefore, 

these 

endpoints are 

valid for

quantitative 

risk 

assessment. 

Acute 

850.1075

15.8 Sheepshead 

minnow Cyprinodon 

variegatus

LC50> 68 mg ai/L

NOAEC=68 mg ai/L

Slightly Toxic

45428606

Supplemental

(Formerly 

Acceptable)

2

None

Estuarine/ 

Marine 

Invertebrates

Acute 

850.1035

97.1 Mysid shrimp 

Mysidopsis bahia

96-hour LC50=0.94 μg 

ai/L

NOAEC= 0.27 μg ai/L

Highly Toxic

45434917

SupplementalEnvironmental 

conditions (pH, 

salinity, vessel

size, 

temperature) 

all outside 

recommended 

levels. Mean 

measured 

concentration 

were only 7.8-

16% of 

nominal. 

Endpoints are 

valid for 

quantitative

risk 

assessment.

Lethargic 

swimming, 

loss of 

equilibrium

Acute

850.1025

97.1 Eastern Oyster 

Crassostrea virginica

96 Hour EC50= 0.59 μg 

ai/L

NOAEC <0.11 μg ai/L

45434916

SupplementalShell 

deposition was 

lower than 

minimum 2.0 

mm meaning 

there was 

uncertainty 

with the 

control quality. 

Results of this 

study can be 

Shell 

Deposition 
42

Taxa Study Type % ai Species Toxicity Value & 

Category

MRID & Status Endpoints 

Affected

used to 

qualitatively 

assess risk.

Chronic

850.1350

NA Mysid Shrimp

Mysidopsis bahia

NOAEC = 0.38 μg/L

(Estimated using 

Acute/Chronic ratio) 

Acequinocyl is 

extremely 

unstable in 

seawater 

(MRID 

47914901). As 

a result, a 

waiver request 

was granted 

for studies 

assessing 

chronic 

exposure to 

estuarine

/marine 

invertebrates 

under flowthrough 

conditions 

(MRID 

47256201). 

For the 

purposes of 

risk 

assessment, 

chronic effect 

endpoints will 

be estimated 

by taking the 

acute to 

chronic ratio of 

endpoints 

observed in 

freshwater 

invertebrates.2

Aquatic 

Plants

Non Vascular

850.4400

15 Green Algae

Pseudokirchneriella 

subcapitata

72-hour EC50= 0.96 mg 

ai/L 

NOAEC= 0.0017 mg 

ai/L

LOAEC=0.0055 mg ai/L 

45428611

Supplemental72 hour study 

shorter than 

the 

recommended 

96 hour. 

Endpoints may 

Cell Density
43

Taxa Study Type % ai Species Toxicity Value & 

Category

MRID & Status Endpoints 

Affected

be used for 

quantitative 

risk

assessment. 

Non Vascular

850.4400

97.1 Green Algae

Pseudokirchneriella 

subcapitata

72-hour EC50>78.0 mg 

ai/L 

NOAEC ≥ 78.0 mg ai/L

45435008

Supplemental72 hour study 

shorter than 

the 

recommended 

96 hour. 

Endpoints valid 

for quantitative 

use in risk 

assessment

none

Terrestrial 

Invertebrates

Adult Acute 

Contact

850.3020

97.1 Honeybee Apis 

mellifera

48-Hour LD50>100 μg 

ai/bee

NOAEL= 100 μg ai/bee

Practically Nontoxic

45435007

Acceptable

None

Adult Acute 

Oral

Non-Guideline

15.4 Honeybee Apis 

mellifera

72-Hour LD50> 315 μg 

ai/bee

NOAEL= 43.8 μg ai/bee

45428608

Supplementalstudy uses TEP. 

Endpoints can 

be used for 

quantitative 

assessment of

risk to 

honeybees. 

None

Adult Acute 

Contact

850.3020

15.4 Honeybee Apis 

mellifera

72-Hour LD50> 350 μg 

ai/bee

NOAEL= 175 μg ai/bee

Practically nontoxic

45428608

Acceptable

None

Earthworm 

Subchronic 

850.6200

97.1 Earthworm Eisenia 

fetida

LC50> 1000 mg ai/kg

NOAEC= 500 mg ai/kg

LOAEC= 1000 mg ai/kg

45435009

SupplementalNon Guideline 

study

Reductions in 

body weight 

gain

Acute Toxicity

Earthworm –

850.6200

15.6 Earthworm Eisenia 

fetida

LC50> 156 mg ai/kg

NOAEC= 156 mg ai/kg

LOAEC >156 mg ai/kg

45782304 

SupplementalNon Guideline 

study

Weight loss

Terrestrial 

Plants

Seedling 

Emergence 

Monocot

15.3 Oat Avena sativa, 

Onion Allium cepa,

Corn Zea mays,

Most Sensitive 

Monocot: None

EC25> 0.9 lb ai/a

45428609

Acceptable

None
44

Taxa Study Type % ai Species Toxicity Value & 

Category

MRID & Status Endpoints 

Affected

850.4100 Ryegrass Lolium 

perenne

NOAEC= 0.9 lb ai/a

Seedling 

Emergence 

Dicot

850.4100

15.3 Carrot Daucus 

carota, 

Rapeseed Brassica 

napus, 

Beets Beta

vulgaris,

Tomato 

Lycopersicon 

esculentum, 

Cabbage Brassica

Oleracea

Soybean Glycine 

max

Most sensitive dicot: 

Carrot

EC25= 0.7 lb ai/a

NOAEC= 0.3 lb ai/a

45428609

Acceptable

Shoot Height

Vegetative 

Vigor

Monocot

850.4150

15.3 Oats Avena sativa, 

Onion Allium cepa, 

Corn Zea mays, 

Ryegrass Lolium 

perenne 

Most Sensitive Species: 

None

EC25> 0.9 lbs ai/a

NOAEC= 0.9 lbs ai/a

45428610

Acceptable

None

Vegetative 

Vigor 

Dicot

850.4150

15.3 Carrot Daucus 

carota,

Rapeseed Brassica 

napus, Beets Beta 

vulgaris

Cabbage Brassica

Oleracea

Tomato 

Lycopersicon 

esculentum, 

Soybean Glycine 

max

Most Sensitive Species: 

Beets and Cabbage 

EC25> 0.9 lbs ai/a

NOAEC= 0.3 lbs ai/a

45428610

Acceptable

Shoot Height

1 Centrifuged samples yielded measured active ingredient concentrations of 13-19% of the uncentrifuged. For the 

purposes of risk assessment, the NOAEC will be 0.52 mg ai/L X 0.13 mg ai/L= 0.07 mg ai/L, and this adjusted value 

will be used to calculate Risk Quotients. 

2 For the purposes of risk assessment, an estimated chronic toxicity value for estuarine/marine invertebrates was 

assumed by taking the acute to chronic ratio (ACR) observed in freshwater invertebrate studies (MRIDs 46372101; 

45434922) (2.4μg/L/0.98μg/L=2.45) and applying it to the most sensitive estuarine marine acute endpoint (MRID 

45434917) (0.94 μg/L/2.45=0.38 μg/L).

Appendix 5- SIP Inputs and Outputs
45

Inputs

Parameter Value

Chemical name

Solubility (in water at 25oC; mg/L) 0.00669

Mammalian LD50 (mg/kg-bw) 5000

Mammalian test species laboratory rat

Body weight (g) of "other" mammalian species

Mammalian NOAEL (mg/kg-bw) 100

Mammalian test species laboratory rat

Body weight (g) of "other" mammalian species

Avian LD50 (mg/kg-bw) 2000

Avian test species mallard duck

Body weight (g) of "other" avian species

Mineau scaling factor 1.15

Mallard NOAEC (mg/kg-diet) 100

Bobwhite quail NOAEC (mg/kg-diet) 2515

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) 0.0012 0.0012

Adjusted toxicity value (mg/kg-bw) 3845.8028 76.9161

Ratio of exposure to toxicity 0.0000 0.0000

Conclusion*

Drinking water exposure alone is 

NOT a potential concern for 

mammals

Drinking water exposure alone is 

NOT a potential concern for 

mammals

Table 3. Avian Results

Parameter Acute Chronic

Upper bound exposure (mg/kg-bw) 0.0054 0.0054

Adjusted toxicity value (mg/kg-bw) 1038.4508 4.9613

Ratio of exposure to acute toxicity 0.0000 0.0011

Conclusion*

Drinking water exposure alone is 

NOT a potential concern for 

birds

Drinking water exposure alone is 

NOT a potential concern for 

birds

Appendix 6- STIR inputs and outputs for acequinocyl 
46

Input

Application and Chemical Information

Enter Chemical Name Acequinocyl 

Enter Chemical Use Miticide

Is the Application a Spray? (enter y or n) y

If Spray What Type (enter ground or air) ground

Enter Chemical Molecular Weight (g/mole) 335

Enter Chemical Vapor Pressure (mmHg) 1.26E-08

Enter Application Rate (lb a.i./acre) 0.3

Toxicity Properties

Bird

Enter Lowest Bird Oral LD50 (mg/kg bw) 2000

Enter Mineau Scaling Factor 1.15

Enter Tested Bird Weight (kg) 1.58

Mammal

Enter Lowest Rat Oral LD50 (mg/kg bw) 5000

Enter Lowest Rat Inhalation LC50 (mg/L) 0.84

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) 2.27E-04

Maximum 1-hour Vapor Inhalation Dose (mg/kg) 2.86E-05

Adjusted Inhalation LD50 1.35E+00

Ratio of Vapor Dose to Adjusted Inhalation LD50 2.11E-05 Exposure not Likely Significant

Maximum Post-treatment Spray Inhalation Dose (mg/kg) 3.17E-02

Ratio of Droplet Inhalation Dose to Adjusted Inhalation LD50 2.35E-02 Exposure not Likely Significant

Results Mammalian (0.015 kg )

Maximum Vapor Concentration in Air at Saturation (mg/m3) 2.27E-04

Maximum 1-hour Vapor Inhalation Dose (mg/kg) 3.59E-05

Adjusted Inhalation LD50 5.00E+01

Ratio of Vapor Dose to Adjusted Inhalation LD50 7.18E-07 Exposure not Likely Significant

Maximum Post-treatment Spray Inhalation Dose (mg/kg) 3.98E-02

Ratio of Droplet Inhalation Dose to Adjusted Inhalation LD50 7.97E-04 Exposure not Likely Significant