2 

registration review and provides an overview of the environmental fate, ecological effects, and 

potential risks associated with the use of spiromesifen. It describes uncertainties which may be 

encountered in the risk assessment and identifies additional studies and other information that 

would be beneficial to its conduct. Below is a summary of data needs and uncertainties. 

The environmental fate database is relatively complete; however, the following studies are 

recommended to support the risk assessment for spiromesifen (40 CFR Part 158.1300): 

o Environmental chemistry methods (ECM) for soil and water with associated 

independent laboratory validation (ILV) (OCSPP Guideline §850.6100) is needed 

to support field dissipation studies. 

The ECM/ILVs are a standard data requirement for a terrestrial use pattern and are not available 

for the methods used in the dissipation studies. 

The ecological database is incomplete based on the data requirements outlined in the 40CFR158 

Subpart G1

. Ecotoxicology data gaps2 include: 

 Aquatic: 

o OCSPP §850.1400 Estuarine/marine fish early-life stage toxicity 

o OCSPP §850.4500 Algal toxicity 

 Freshwater diatom (Navicula pelliculosa) and a marine diatom 

(Skeletonema costatum) species 

o OCSPP §850.4550 Cyanobacteria (Anabaena flos-aquae) toxicity 

o Non-guideline: Whole sediment chronic freshwater invertebrate with Hyalella 

azteca (42 days)3

o Non-guideline: Whole sediment chronic estuarine/marine invertebrate with 

Leptocheirus plumulosus (28 days)4

 Terrestrial 

o OECD Test Guideline 237: Honey bee larval acute toxicity (single exposure)5

(TGAI) 

o Non-Guideline: Honey bee larval chronic (21-day) toxicity (repeated 

exposure) (TGAI); see OECD draft guidance document6

. 

o Non-Guideline: Honey bee adult chronic (10-day) oral toxicity (TGAI) 

o Special Study (Tier 2): Field trial of residues in pollen and nectar (TEP) 

o Special Study (Tier 2): Semi-field testing for pollinators (tunnel or colony 

feeding studies) (TEP) 

 

1

 CFR. 2013. Title 40 (Protection of the Environment), Chapter 1 (Environmental Protection Agency), Subchapter E (Pesticide Programs), Part 

158 (Data Requirements for Pesticides), Subpart G (Ecological Effects) http://www.ecfr.gov/cgi-bin/textidx?c=ecfr&SID=ff5c7fef3645e7cd5abceca0b597bccb&rgn=div6&view=text&node=40:25.0.1.1.9.7&idno=40 2

 A complete listing of all the environmental fate and ecotoxicology data gaps, along with justification according to 40 CFR, Part 158-Subpart G, 

are listed in Section 11 of this document. 3,4 A tiered testing approach may be considered for requesting chronic sediment toxicity testing. Sediment toxicity testing would first be 

conducted using the subchronic (10-d) sediment toxicity test guidelines (OSCPP 850.175 and 850.1740). Pending a comparison of estimated 

environmental concentrations (EEC) in sediment and pore water with toxicity results from the 10-d sediment toxicity studies, the need for one or 

more chronic sediment toxicity studies would be determined. 

5

 OECD. 2013. OECD Guidelines for the Testing of Chemicals. Honey bee (Apis mellifera) larval toxicity test, single exposure. OECD/OCDE 

237. Adopted 26 July 2013. http://www.oecd-ilibrary.org/environment/test-no-237-honey-bee-apis-mellifera-larval-toxicity-test-singleexposure_9789264203723-en 6

 OECD. 2013. OECD Draft Guidance Document. Honey bee (Apis mellifera) larval toxicity test, repeated exposure. Revision of June 2013 

draft GD, 25 November 2013. http://www.oecd.org/env/ehs/testing/Draft_GD_honeybees_rep_exp_for_2nd_CR_25_November_2013.pdf 
3 

o 850.3040 (Tier 3) Full-Field testing for pollinators (TEP) 

All studies are to be conducted using technical grade active ingredient (TGAI) unless there is 

evidence the typical end-product (TEP) enhances the toxicity of the formulation. 

EPA recently posted its guidance7

 for assessing risks of pesticides to bees and consistent with 

this guidance a suite of tests is recommended for evaluating the potential toxicity of pesticides to 

bees. Although data from the acute contact toxicity test (OCSPP 850.3020) with young adult 

honey bees (Apis mellifera) indicates spiromesifen is practically non-toxic to bees on an acute 

exposure basis, there is uncertainty regarding the potential acute and chronic effects of the 

compound on honey bee larval development and survival as well as potential for chronic effects 

of adult bees. Data suggest that spiromesifen is not extensively translocated in plants, although it 

is not clear whether the studies were long enough in duration to capture all potential 

translocation. Further, there is uncertainty regarding the extent to which adjuvants may increase 

uptake of the compound by leaves. While autoradiographs of plants treated with spiromesifen do 

not show extensive movement beyond leaves, there appears to be movement within the leaves 

(i.e., translaminar systemicity) (USEPA, 2011). Additionally, insect pollinators may be exposed 

if these compounds are applied at bloom or when bees are foraging on extra-floral nectaries. 

Therefore, residues may be present in pollen and/or nectar and represent a route of exposure for 

bees through both contact and ingestion. Additional data on pollinators are needed to 

characterize the potential risk associated with spiromesifen use to all developmental stages of 

honey bees, as sensitivity may vary according to life-stage and length of exposure (adult vs. 

larval and acute vs. chronic, respectively). As described in the guidance for assessing risks to 

bees, depending on the outcome of the screening-level risk assessment, additional studies of bees 

at the colony level under semi- and full-field conditions may also be recommended. 

In the absence of the above toxicity data, uncertainties in the assessment of spiromesifen include 

the potential for adverse effects from exposure to spiromesifen for the following non-target 

organisms: estuarine/marine fish (chronic exposure), nonvascular aquatic plants and algae, 

freshwater and estuarine/marine benthic invertebrates (chronic exposure), and terrestrial 

invertebrates (honey bee larval acute and chronic toxicity, and adult chronic toxicity). 

 

 

7

 USEPA. 2014. Guidance for Assessing Pesticide Risks to Bees. Office of Pesticide Programs. United States Environmental Protection Agency. 

Available at 

http://www.epa.gov/pesticides/science/efed/policy_guidance/team_authors/terrestrial_biology_tech_team/GuidanceAssessingPesticideRisk2Bees.

pdf 
4 

2. Introduction 

Spiromesifen (3,3-dimethyl-,2-oxo-3-(2,4,6-trimethylphenyl)-1-oxaspiro[4,4]non 3-en-4-yl ester 

(CAS No.: 283594-90-1) belongs to the keto-enol class of pesticides. The compound is a 

spirocyclic tetronic acid (2,4(3H,SH)-furandione derivative; closely related pesticide include 

spirodiclofen (PC Code 124871; CAS 148477-71-8), a broad-spectrum acaricide (Fischer and 

Benet-Buchholz, 2002) and spirotetramat (PC Code 392201; CAS 203313-25-1). These 

pesticides act through the inhibition of lipid biosynthesis (Arthur et al., 2003), especially 

triglycerides and free fatty acids. The spirocyclic tetronic acids were developed after it was 

discovered that a predecessor group of herbicidal chemicals, the bicyclic tetramic acids, were not 

only selective against monocotyledonous grasses but were also effective miticides (Fischer and 

Benet-Buchholz, 2002). Across the keto-enols, the compounds vary with respect to their 

systemicity, i.e., the extent to which they are taken up by plants and distributed to various parts 

of the plant. Spirotetramat is considered fully systemic and undergoes transport through both 

xylem and phloem tissues whereas spirodiclofen is not systemic at all; spiromesifen exhibits 

limited systemicity and is believed to fall between other chemicals within the class. 

Spiromesifen has been classified as an insect growth regulator (IGR) by the Insecticide 

Resistance Action Committee (IRAC)8. The mechanism of action (MOA) classification scheme 

developed and endorsed by IRAC is based on the best available evidence of the MOA of 

available insecticides. According to the IRAC, details of the listing have been agreed by IRAC 

companies and approved by internationally recognized industrial and academic insect 

toxicologists and biochemists9. Based on the IRAC analysis, tetronic and tetramic acid 

derivatives, which includes spiromesifen, are classified as an IGR through inhibition of acetyl 

CoA carboxylase in the lipid synthesis and growth regulation pathways. 

In support of this preliminary problem formulation, the Environmental Fate and Effects Division 

(EFED) examined the most recent environmental fate and ecological risk assessments as well as 

the updated toxicity, exposure, and usage information for spiromesifen to determine if additional 

data are needed to support Registration Review. In addition, EFED considered the latest Agency 

science policies and risk assessment methodologies. 

3. Use Characterization 

Spiromesifen is formulated as flowable and emulsifiable concentrate with application methods 

that include: ground spray, aerial spray, and chemigation. The pesticide is currently registered for 

use on wheat, sorghum, dry peas, mint, leafy petioles crop subgroup (4B), almond, apples, 

artichokes, broccoli, cabbage, cauliflower, cranberries, corn, cucumbers, eggplant, lettuce, oats, 

peppers, potatoes, pumpkin, spinach, squash, strawberries, sweet corn, tomatoes and 

watermelons. Additionally, it is registered for non-food crop such as ornamentals and cotton (3 

lbs a.i./A/year and 0.50 lbs a.i./A/year, respectively). The current maximum single application 

 

8 IRAC. 2014. IRAC MoA Classification Scheme.  Issued February 2014, version 7.3.  Prepared by: IRAC International MoA Working Group.  

Available at: http://www.irac‐online.org/documents/moa‐classification/?ext=pdf 9 Ibid IRAC 2014,
5 

rate is 0.25 pounds of active ingredient per acre per year (lbs a.i./A) for berries, with three 

applications and a maximum annual application of 0.75 lbs a.i./A/year. 

A Screening Level Usage Analysis (SLUA) was prepared by Biological and Economical 

Analysis Division (BEAD) for spiromesifen in 2014 that provides an estimate of pesticide 

agricultural usage data; EFED will use these data to evaluate different use profiles. Use on corn 

over the SLUA timeframe (2004-2012) accounted for less than 1% of the agricultural 

spiromesifen usage. However, the average pounds of active ingredient used on corn was 30,000. 

Usage of spiromesifen in terms of pounds applied and number of acres treated both showed a 

steady increase from 2005 (first registered ~15,000 lbs.) to 2012 (~100,000 lbs a.i.) (USEPA, 

2014). 

A review of total spiromesifen usage data for the last 5 years indicates that the major use sites are 

corn, potatoes, and strawberries, accounting for 86% of total usage in terms of pounds applied 

and 85% of acres treated for these crops. While corn, potatoes, and strawberries have the highest 

percentages of lbs. applied and acres treated, the crop with the highest percent crop treated is 

eggplant at 45%. This indicates that spiromesifen plays an important role in pest control for some 

crops grown in relative small amounts. Texas is the state with highest usage in terms of both 

total pounds of spiromesifen applied and total acres treated. (USEPA, 2014). 

According to the SLUA, average single application rates for spiromesifen across all crops from 

2008 to 2012 range from 0.094lbs a.i./acre for artichokes to 0.246 lbs a.i./acre for strawberries. 

4. Conclusions from Previous Risk Assessments 

The most recent risk assessment was completed in June 7, 2010 for the use of spiromesifen on 

wheat, sorghum, dry peas, mint and leafy petioles crop subgroup (4B) (USEPA, 2010a). Based 

on previous analyses, the registered uses of spiromesifen may result in mortality on an acute 

exposure basis in freshwater fish and mollusks (freshwater and marine) and chronic effects on 

reproduction/survival in both terrestrial and aquatic animals. 

Previous assessments noted that as a new class of pesticide with a purportedly novel mode of 

action, there are uncertainties associated with risk estimates for spiromesifen. Although the 

parent is likely to be non-persistent and immobile, its degradate (spiromesifen enol) is persistent 

and mobile. The likelihood of adverse effects to aquatic animals from acute exposure may be 

limited by the solubility of spiromesifen; however, the current battery of chronic terrestrial 

animal toxicity tests do not differentiate whether chronic effects are due to parent spiromesifen 

or its degradates. Uncertainty was also identified with respect to the potential effects of 

spiromesifen exposure on honey bee (Apis mellifera) larval development and how this may 

impact the colony. In previous ecological assessments, risk conclusions were based on the 

parent compound alone and not degradates. 

a. Drinking Water Exposure Assessments 

In previous assessments, the uses of spiromesifen on cranberries and ornamentals were expected 

to pose the highest potential exposure through drinking water due to these uses having the 

highest annual application rate (0.25 lb a.i./A x 3 applications/crop season, 7-day interval) 
6 

cranberries and 0.25 lb a.i./A x 3 applications/season for ornamental (four seasons were 

assumed; interval not specified) and were therefore used as the basis for estimated drinking water 

concentrations (EDWCs) in surface as well as ground water (USEPA, 2010b). In addition, these 

exposure estimates reflected total residues of concern that included spiromesifen, BSN2060-enol 

and the BSN2060-carboxy degradate. The EDWCs were calculated using the Pesticide Root 

Zone Model coupled with the Exposure Analysis Model System (PRZM/EXAMS) for surface 

water and the Screening Concentration in Ground Water (SCIGROW) model for ground water. 

For surface water, the acute (peak) value was 199 ppb and 86 ppb for cranberries and 

ornamentals uses, respectively, and chronic values were 188 ppb and 86 ppb, respectively. The 

ground water screening concentration was 86 ppb for both uses. 

b. Clean Water Act Programs 

Spiromesifen is not identified as a cause of impairment for any water bodies listed as impaired 

under section 303(d) of the Clean Water Act. No Total Maximum Daily Loads (TMDLs) or 

water quality criteria have been developed for spiromesifen10. 

Office of Pesticide Programs’ Aquatic Life Benchmarks11 have been established for 

spiromesifen. Benchmarks are extracted from the most recent publically available OPP risk 

assessment for the pesticide and are based on the most sensitive aquatic toxicity data. These 

values are estimates of the concentration below which pesticides are not expected to harm 

aquatic life. 

5. Environmental Fate and Transport 

Spiromesifen is characterized as nonvolatile, relatively hydrophobic, and hardly mobile to 

immobile (FAO 2000) in soil. The parent compound is not expected persist as its degradation is 

moderately rapid in the environment (Goring et al. 1975), mainly through biotic (i.e., microbially 

mediated metabolism) and abiotic (i.e., hydrolysis, especially under alkaline conditions) routes. 

Due to the limited soil mobility of spiromesifen, erosion, i.e., runoff of sediment-bound residues, 

will be an important means of transport off of agricultural fields and the compound will associate 

predominately with the sediment phase of water bodies. Spiromesifen parent is not a ground 

water concern due to the chemical’s limited soil mobility and moderate biodegradation half-lives 

(on the order of weeks). However, its major transformation products (i.e., BSN2060-enol and 

BSN2060-carboxy) are highly mobile and generally more persistent than the parent compound. 

Therefore, these degradates may reach ground water and surface water bodies more readily than 

spiromesifen parent. 

Table 1 summarizes the physicochemical properties of spiromesifen. Briefly, spiromesifen is 

nonvolatile on dry surfaces due to a low vapor pressure (7.5 x 10-8 torr at 25°C). However, the 

compound is slightly volatile from water due to its relatively low solubility in water (0.13 mg/L 

at 25oC). 

 

10 http://iaspub.epa.gov/tmdl_waters10/attains_nation_cy.cause_detail_303d?p_cause_group_id=885 11 USEPA. 2014. Office of Pesticide Programs’ Aquatic Life Benchmarks. 

http://www.epa.gov/oppefed1/ecorisk_ders/aquatic_life_benchmark.htm 
7 

 

Although, the compound has relatively high Kow (4.6), bioconcentration factors are 916X, 

1295X, and 512X for the whole fish, non-edible, and edible tissues, respectively. However, 

spiromesifen rapidly depurated from fish tissues in freshwater, with a depuration half-life of 2.3 

days. These BCF values suggest that the compound is metabolized/excreted in fish but there is 

uncertainty as to the extent to which other aquatic organisms may be able to do the same. 

Spiromesifen is characterized as hardly mobile to immobile in soil, with organic carbon partition 

coefficient (KOC) values of 45,900 to 106,000 L/kgoc. These sorption values indicate that 

spiromesifen parent will not readily leach into ground water, but may move into surface water 

sorbed to sediment in runoff, especially in acidic to neutral environments. 

Spiromesifen degrades in the environment mainly through hydrolysis, although degradation via 

biotic and other abiotic processes may also occur (e.g. photolysis in water). Hydrolysis of 

spiromesifen is pH-dependent, as the compound degrades readily in alkaline environments (halflife of 4.4 days at pH 9) but more slowly in neutral to acidic conditions (half-lives of 26 days at 

pH 7 and 48 days at pH 4). The major hydrolytic products are BSN2060-enol (up to 96% of the 

applied) and 3'3-dimethylbutanoic acid. 

Table 1. Chemical Properties and Environmental Fate Parameters of Spiromesifen 

Parameter Value Description Reference 

Chemical Classification Keto-enol class 

MRID 46059302 

Molecular Formula C23H30O4 

PC Code 024875 

Chemical Name 

(IUPAC) 

3-mesityl-2-oxo-1-oxaspiro[4.4]non-3-en4-yl 3,3-dimethylbutyrate 

Chemical Name (CAS) 

2-oxo-3-(2,4,6-trimethylphenyl)-1-

oxaspiro[4.4]non-3-en-4-yl 3,3-

dimethylbutanoate

CAS Number 283594-90-1 

Water Solubility at 

25o

C (ppm) 0.13 Hydrophobic MRID 45854501 

Pesticide Classification Insecticide 

MRID 46059302 

Molecular Weight 370.5 g/mol 

Vapor pressure (25oC) 7.5 x 10-8 torr Non volatile 

Henry's Law Constant 

at pH 7 2.8 x 10-7 atm m3

/mol Non volatile 

Log Octanol/Water 

Partition coefficient 

(log Kow) 

3.6 x 104 Potential to 

bioaccumulate 

Persistence 

Hydrolysis 

48 d (pH 4) 

26 d (pH 7) 

4.4 d (pH 9) 

Non to slightly 

persistent MRID 45819734 
8 

Parameter Value Description Reference 

Direct photolysis in 

water at pH 7 6.1 d (dark control-adjusted) Non persistent MRID 45819811 

Photolysis on soil No evidence of degradation (dark controladjusted) Stable MRID 45819801 

Aerobic soil 

metabolism 

12 d (Hesperia; Calif.; pH 8.5) 

16 d (Hesperia; Calif.; pH 9.0) 

19 d (not reported; Germany; pH 7.2) 

20 d (not reported; Germany; pH 7.1) 

45 d (not reported; Texas; pH 7.1) 

49 d (not reported; Calif.; pH 6.9) 

Non to slightly 

persistent 

MRID 45819808, 

MRID 45819824, 

MRID 45819825 

Anaerobic soil 

metabolism Not submitted 

Anaerobic Aquatic 

metabolism 

18 d (pH 7.1-8.1) Non persistent MRID 

45819802

Aerobic aquatic 

metabolism 

12 d (pH 7.2-8.6) 

18 d (pH 3.7-8.3)

Non persistent MRID 45819803 

MRID 45819804 

Field Dissipation 

Terrestrial field 

dissipation 

2.1 d (Hesperia; Calif.; pH 8.1) 

4.3 d (Quincy; Wash.; pH 6.9) 

4.7 d (Amarillo; Texas; pH 8.1) 

9.6 d (Millhopper; Florida; pH 6.9) 

Non persistent 

MRIDs 45819805 

45819807 

45819812 

45819813 

Mobility 

Leaching and 

absorption/desorption 

Parent 

Koc in mL/g 

45,296 (sandy loam) 

79,472 (silt loam) 

46,816 (loam) 

106,000 (clay loam) 

Immobile 45819806 

BSN2060-enol Metabolite 

Koc and Kd in mL/g 

10 and 0.0549 (sandy loam) 

5.6 and 0.083 (silty clay loam) 

5.0 and 0.0908 (sandy loam) 

 2.5 and 0.0659 (silt) 

Mobile 45819819 

BSN2060-4-carboxy Metabolite 

Koc and Kd in mL/g 

3.0 and 0.65 (silty clay loam) 

Mobile 45819821 

Fish Bioconcentration 

Bioconcentration in 

fish (BCF) 

916x (whole fish); 

512x (edible tissue) 

1295(~viscera) 

Depuration time=2.3 d 

Prone to bioaccumulate 

but fast depuration time 45819720 

AR=Applied Radioactivity 

Classification of persistency was based on Goring scale, 1975. 

Mobility was described using FAO, 2000.
9 

a. Transformation Products 

Two major degradates (occurring at greater than 10% of the applied) were identified in the 

registrant-submitted studies. These were 1-oxaspiro[4.4]non-3-en-2-one, 4- hydroxy-3-(2,4,6-

trimethylphenyl) [i. e., BSN2060-enol] and benzoic acid, 4-(4-hydroxy-2-oxo-1-

oxaspiro[4.4]non-3-en-3-yl)-3,5-dimethyl [i.e., BSN2060-4-carboxy]. BSN2060-enol is a 

hydrolytic degradate that appeared in all degradation studies at levels up to 100% of the applied; 

whereas BSN2060-4-carboxy was only formed at substantial levels (up to 14% of the applied) in 

the aerobic soil metabolism studies. An unidentified conjugate of BSN2060-enol was also 

formed in an aerobic aquatic system, at up to 11% of the applied. Summary details of the 

degradates of spiromesifen are listed in Table 2. Independent studies on degradate properties 

were submitted only to address sorption of the two major identified degradates. Other properties 

such as photolysis, hydrolysis, aerobic soil and aerobic aquatic metabolism study have been 

inferred from studies on the parent. 

Relative to the parent compound, sorption coefficients for both BSN2060-enol and BSN2060-4-

carboxy were very low in the studies with KOC values that ranged from 2.5 to 10 mL/g and 3.0 

mL/g respectively. 

In photolysis studies on the parent, there was no indication that either BSN2060-enol or 

BSN2060-4-carboxy degrades significantly by photolysis or hydrolysis. 
10 

Table 2. Spiromesifen and its Environmental Degradates 

Chemical Name and Structure Maximum Percent of 

Applied Dose 

(interval) 

Final Percent of Applied 

Dose 

(study duration)

MRID 

Spiromesifen (parent) IUPAC Name: 3-mesityl-2-oxo-1-oxaspiro[4.4]non-3-en-4-yl 3,3-dimethylbutyrate CAS Name: 2-oxo-3-(2,4,6-trimethylphenyl)-1-oxaspiro[4.4]non-3-en-4-yl 3,3-dimethylbutanoateCAS. No.: 283594-90-1 Synonyms: BSN2060 BSN2060-enol CAS Name: 4-hydroxy-3-(2,4,6-trimethylphenyl)-1-oxaspiro[4.4]non-3-en-2-one CAS No.: 148476-30-6

Synonyms: spiromesifen-enol; enol; BSN0546; BSN0546-dihydrofuranone; tetronic acid BSN 2060 

29.7% (672 hrs) 27.5% (720 hrs) 45819734 H

54.3% (720 hrs) 54.3% (720 hrs) 95.7% (720 hrs) 95.7% (720 hrs) light-12.3% (120 hrs) dark-13.9% (216 hrs) 

light-12.3% (120 hrs) dark-13.9% (216 hrs) 

46059301 

light-11.6% (10 d) dark-24.1% (10 d) 

light-11.6% (10 d) dark-24.1% (10 d) 

45819801 Soi

77.1% (7 d) 22.0% (120 d) 45819825 Ae85.0% (14 d) 45.3% (90 d) 45819808 102% (120 d) 102% (120 d) 45819802 Ana

met

99.1% (64 d) 85.6% (121 d) 45819803 Aer

met

89.0% (45 d) 69.9% (90 d) 45819804 

O

H3C

CH3

O

O

O

H3C

H3C CH2

CH3

CH3

C

O

H3C

CH3

O

HO

H3C
11 

Chemical Name and Structure Maximum Percent of 

Applied Dose 

(interval) 

Final Percent of Applied 

Dose 

(study duration)

MRID 

BSN2060-4-carboxy CAS Name: 4-(4-hydroxy-2-oxo-1-oxaspiro[4.4]non-3-en-3-yl)-3,5-dimethyl-benzoic acid CAS No.: Not reported. Synonyms: BSN-4-carboxy; 4-carboxy; BSN2060 acid; KTS 9439-6-2; 4-carboxyl-KTS9439 

11.3% (90 d) 11.1% (120 d) 45819825 Aer

(835

14.1% (90 d) 14.1% (90 d) 45819808 

BSN2060-2-hydroxymethyl CAS Name: 4-hydroxy-3-[2-(hydroxymethyl)-4,6-dimethylphenyl]-1-oxaspiro[4.4]non-3-en-2-one CAS No.: Not reported

Synonyms: WAK 6925 

2.3% (62 d) 2.2% (90 d) 45819808 Aer

(835

BSN2060-cyclobutyl photoisomer CAS name: 3,5'-oxospiro[bicyclo[4.2.0]octa-1,3,5-triene-7,4'(5',H)-furan-2'(3',H),1"-cyclopentan]-3'-yl 3,3-dimethylbutanoateCAS No.: Not reported

light-35.8% (120 hrs) 

dark-ND 

light-35.8% (120 hrs) dark-ND 

46059301 Aqu

(835

O

H3C

CH3

O

HO

HOOC

O

OH

O

OH

H

O

O

O O
12 

Chemical Name and Structure Maximum Percent of 

Applied Dose 

(interval) 

Final Percent of Applied 

Dose 

(study duration)

MRID 

BSN2060-enol photoisomer CAS name: 8',8'a-dihydro-8'-hydroxy-4',6'-dimethylspiro[cyclopentane-1,1'-[1H]indeno[1,2-c]furan]-3'(3'aH)-one CAS No.: Not reported

light-36.7% (120 hrs) dark-ND 

light-36.7% (120 hrs) dark-ND 

46059301 Aqu

(835

BSN2060-pentanone CAS name: Not reported CAS No.: Not reported

Synonyms: BSN2060-ketoenol 

6.7% (30 d) 0.3% (365 d) 45819824 Aer

3.8% (30 d) 0.3% (272-365 d) (8351.4% (7 d) ND (120 d) 1.9% (7 d) 0.1% (120 d) 5.1% (62 d) 4.6% (120 d) 45819825 1.4% (62 d) 1.1% (90 d) 45819808 

Carbon dioxide (radiolabeled) 72.3% (272 d) 72.1% (365 d) 45819824 Aer

78.9% (835

(365 d) 78.9% (365 d) 

71.0% (90 d) 70.3% (120 d) 67.8% (120 d) 67.8% (120 d) 30.1% (120 d) 30.1% (120 d) 45819825 14.3% (90 d) 14.3% (90 d) 45819808 

Unidentified BSN2060-enol conjugate 11.1% (20 d) 3.3% (90 d) 45819804 Aer

met

NA = Not analyzed. ND = Not detected. 

O

OH

O

O C O

O

H3C

CH3

O

HO

H3C

O
13 

6. Receptors 

A receptor is a biological entity that is exposed to a stressor (USEPA 1998). For this assessment, 

the receptors include terrestrial and aquatic plants and animals inhabiting fields where 

spiromesifen is applied, and those inhabiting non-target areas to which spiromesifen may be 

transported (e.g., via spray drift and runoff). Consistent with the process described in the 

Overview Document (USEPA 2004a), the assessment of spiromesifen uses a surrogate species 

approach. Toxicological data generated from surrogate test species, which are intended to be 

representative of broad taxonomic groups, are used to extrapolate to potential effects on a variety 

of species (receptors) included under these taxonomic groupings. 

The most sensitive acute and chronic toxicity data for spiromesifen across aquatic and terrestrial 

organisms are summarized in Table 3. Spiromesifen is characterized as practically nontoxic to 

terrestrial animals (birds, mammals and bees) on an acute exposure basis as median lethal doses 

exceed the maximum required test thresholds; however, the compound’s acute toxicity to aquatic 

animals is uncertain. Acute aquatic guideline toxicity studies only tested up to what was deemed 

the “practical” solubility limit (approximately 50 μg a.i./L) of spiromesifen in some cases, and 

the median lethal concentrations exceed this test concentration limit. In some cases though, there 

is evidence to suggest that had testing been conducted at concentrations slightly exceeding this 

practical solubility limit, a median effects concentration may have been obtained. The extent of 

effects at the highest concentration tested for Eastern oyster (Crassostrea virginica) suggests that 

estimated environmental concentrations could reach levels where a significant effect could occur 

following acute exposure in spite of the chemical’s limited solubility and propensity to sorb to 

sediments. Also there is uncertainty regarding the potential acute and chronic effects of the 

compound on honey bee larval development and survival as well as potential for chronic effects 

of adult bees. 

Table 3. Summary of Most Sensitive Acute and Chronic Toxicity Data on Spiromesifen for Aquatic and 

Terrestrial Organisms 

Taxonomic Group Study 

Type Species Toxicity Value (measured a.i.) 

Toxicity 

Classification 

MRID 

(Study 

Classification) 

Aquatic Toxicity Endpoints 

Freshwater Fish & 

Aquatic-phase 

Amphibians

Acute Rainbow trout 

(Oncorhynchus 

mykiss) 

96 hr LC50=16.8 μg/L Very highly 

toxic 

458197-07 

(Supplemental) 

Chronic NOAEC=0.49 μg a.i./L 

LOAEC=0.97 μg a.i./L NA 458197-27 

(Supplemental) 

Freshwater 

Invertebrates

Acute Waterflea 

(Daphnia 

magna) 

48 hr EC50 >92.3 μg/L Highly toxic 458197-29 

(Supplemental) 

Chronic NOAEC=0.25 μg a.i./L 

LOAEC=0.45 μg a.i./L NA 458197-13 

(Supplemental) 

Estuarine/Marine 

Fish Acute 

Sheepshead 

minnow 

(Cyprinodon 

variegatus) 

96 hr LC50 >46.3 μg 

a.i./L 

Very highly 

toxic 

458197-08 

(Supplemental) 

Estuarine/Marine 

Invertebrates

Acute 

Eastern oyster 

(Crassostrea 

virginica)

96 hr EC50>26 μg a.i./L 

(96-hr LC50) 

Very highly 

toxic 

458197-15 

(Supplemental) 

Chronic Mysid shrimp NOAEC=11 μg a.i./L NA 458197-11 
14 

(Americamysis 

bahia) 

LOAEC >11 μg a.i./L (Acceptable) 

Freshwater Benthic 

Invertebrates Chronic 

Midge 

(Chironomus 

riparius) 

NOAEC=0.25 mg 

a.i./kg sediment 

LOAEC=0.80 mg a.i./kg 

sediment 

NA 471331-03 

(Acceptable) 

Aquatic Vascular 

Plants NA Duckweed (Lemna gibba)

7-day EC50>101.3 μg 

a.i./L NA 458197-14 (Acceptable) 

Aquatic 

Nonvascular Plants NA 

Green algae 

(Pseudokirchneriella 

subcapitata) 

96-hr EC50 >94 μg a.i./L NA 458197-03 

(Acceptable) 

Terrestrial Toxicity Endpoints

Birds, Reptiles, & 

Terrestrial-phase 

Amphibians

Acute 

(oral) 

Bobwhite quail 

(Colinus 

virginianus)

LD50 >2000 mg/kg Practically 

non-toxic 

458197-23 

(Acceptable) 

Sub-acute 

(dietary) 

Mallard duck 

(Anas 

platyrhynchos) 

LC50 >5278 mg a.i./kg 

diet (5-day study) 

Practically 

non-toxic 

458197-22 

(Acceptable) 

Chronic 

Bobwhite quail 

(Colinus 

virginianus) 

NOAEC=698 mg a.i./kg 

diet 

LOAEC >698 mg a.i./kg 

diet 

NA 471331-01 

(Acceptable) 

Mammals

Acute 

(oral) Norway rat 

(Rattus 

norvegicus)

LD50 >2000 mg/kg Practically 

non-toxic 458195-14 

Chronic 

NOAEC=30 mg a.i./kg 

diet 

LOAEC=120 mg a.i./kg 

diet 

NA 458196-19 

Terrestrial 

Invertebrate

Acute 

(contact) Adult honey 

bee (Apis 

mellifera) 

LC50 >200 μg a.i./bee Practically 

non-toxic 

458197-18 

(Acceptable) 

Acute 

(oral) LC50=64.1μg a.i./bee 458197-17 

(Supplemental) 

Terrestrial Plants – 

Seedling 

Emergence

NA 

Monocot - Rye 

grass 

NOAEC=14 g a.i./ha 

EC25=27 g a.i./ha NA 458196-29 

(Supplemental) Dicot - Turnip NOAEC=57 g a.i./ha 

EC25=220 g a.i./ha 

Terrestrial Plants – 

Vegetative Vigor NA 

Monocot - Rye 

grass 

NOAEC=114 g a.i./ha 

EC25=200 g a.i./ha NA 458196-29 

(Supplemental) Dicot - Turnip NOAEC=57 g a.i./ha 

EC25=180 g a.i./ha 

NA=not applicable 

Toxicity studies on spiromesifen are not limited to laboratory based studies and previous risk 

assessments have identified uncertainty regarding the potential effects of spiromesifen on larval 

honey bee development. Semi-field studies indicated statistically significant (p<0.05) increases 

in larval mortality although these effects did not appear to impair overall colony performance. 

Two full-field studies have also been submitted for the formulated product, but there were 

multiple confounding effects that limited the utility of these studies in determining whether 

brood are affected by exposure to spiromesifen and whether overall colony performance is 

impaired. 
15 

a. Degradate Toxicity Assessment 

Toxicity testing with the primary degradate of spiromesifen (BSN2060-enol) indicated that the 

compound is practically nontoxic to freshwater fish (LC50>102 mg a.i./L; MRID 45819628) and 

freshwater invertebrates (EC50>101 mg a.i./L; MRID 45819730) on an acute exposure basis. 

Chronic toxicity testing of BSN2060-enol did not result in any treatment-related effects on 

growth, reproduction or survival of freshwater fish at the highest concentration tested 

(NOAEC=9.2 mg a.i./L; MRID 45819627). However, there is uncertainty regarding whether 

BSN2060-enol may have impacted time to hatch or time to swim-up since no data were provided 

on either of these endpoints. Chronic toxicity testing of BSN2060-enol indicated an increase in 

adult mortality of freshwater invertebrates at 0.39 mg a.i./L (NOAEC=0.19 mg a.i./L; MRID 

45819701). Aquatic plant toxicity testing of freshwater green algae with BSN2060-enol 

indicated that is orders of magnitude less toxic to aquatic plants than the parent compound, with 

an EC05 of 1.9 mg a.i./L based on reduced cell density (EC50 of 9.8 mg a.i./L; MRID 45819716). 

Toxicity information on the biodegradate of spiromesifen, BSN2060-4-carboxy, is not available. 

b. ECOSAR-Predicted vs. Observed Toxicity Endpoints Relative to Parent 

Spiromesifen 

For ecological exposure, only the parent compound is considered a residue of concern. Major 

environmental transformation products of a compound may be of exposure concern. Available 

environmental fate data indicate that two major transformation products (occurring at greater 

than 10% of the applied) were identified in the registrant-submitted studies. These 

transformation products were the BSN2060-enol and BSN2060-4-carboxy and may be present in 

the environment following use of spiromesifen. These degradates of exposure concern were 

further examined to determine which of them might be a factor in risk (rather than exposure) 

concern. In the absence of toxicity data, predicted acute and chronic toxicity values for the 

major transformation products of bicyclopyrone were estimated using EPA’s Ecological 

Structure Activity Relationships (ECOSAR) tool (v 1.11)12 which is based on quantitative 

structure activity relationships (QSAR) for effects on fish, daphnids, mysids, and green algae. 

Predicted toxicity values were also generated for parent bicyclopyrone and compared to observed 

endpoints from registrant-submitted studies to assess confidence in ECOSAR predictions of the 

toxicity of spiromesifen’s transformation products. 

ECOSAR-predicted toxicity values for parent spiromesifen were roughly an order of magnitude 

less (more toxic) than observed measured toxicity endpoints for chronic mysids and only slightly 

lower for acute green algae. In contrast, acute and chronic freshwater and saltwater fish and 

daphnia, as well as acute mysids and chronic green algae, ECOSAR-predicted values were all 

greater than that of the observed values. No observed measured data is available for chronic 

saltwater fish and chronic green algae for parent spiromesifen. 

 

12 http://www.epa.gov/oppt/newchems/tools/21ecosar.htm
16 

BSN2060-enol and BSN2060-4-carboxy 

While the basic ringed structure is similar to spiromesifen, removal of the largest side group of 

the parent produces the BSN2060-enol degradate. Addition of a carboxylic acid group to the 

BSN2060-enol results in the BSN2060-4-carboxy degradate. Neither of these degradates are 

more toxic than parent spiromesifen, with the BSN2060-4-carboxy degradate showing less 

toxicity than BSN2060-enol. Therefore, the BSN2060-enol and BSN2060-4-carboxy degradates 

will not be considered a stressors of concern in the Registration Review ecological risk 

assessment. 

 Table 4: ECOSAR-predicted and Observed Toxicity Values for Spiromesifen and Major Degradates 

Taxon Exposure 

duration 

Toxicity Value (μg/L) 

Observed ECOSAR-Predicted (Using ECOSAR Class Esters) 

Spiromesifen BSN2060-enol BSN2060-4-

carboxy 

FW fish 96-hr LC50

Chronic value 

16.8 

0.49 

206 

7.0 

1905 

90 

51519 

2789 

SW fish 96-hr LC50

Chronic value 

46.3 

No Data 

244 

73.0 

2527 

541 

71207 

13532 

Daphnid 48-hr EC/LC50 

Chronic Value 

>92.3 

0.251

277 

59.0 

3118 

1122 

90566 

39475 

Mysid 

shrimp 

96-hr LC50

Chronic value 

>26 

11 

32.0 

0.59 

828 

645 

32381 

98033 

Green 

algae 

96-hr EC50

Chronic value 

>94 

No Data 

62.0 

60.0 

932 

493 

30078 

12817 1

Based on available data 

c. Ecological Incidents 

The Ecological Incident Information System (EIIS) is an internal OPP database that houses 

ecological incidents that have been reported to the Agency. When available, EIIS includes date 

and location of an incident, type and magnitude of effects observed in various species, use(s) of 

pesticides known or suspected of contributing to the incident, and results of any chemical residue 

analysis or other analyses conducted during incident investigation. EIIS incidents are 

categorized according to the certainty that the incident resulted from pesticide exposure. A 

search of the EIIS for ecological incidents run on October 22, 2014, identified nine incident 

reports for spiromesifen. All incidences involved plants for either a registered or 

underdetermined use (registered uses included broccoli, corn, greenhouse, and ornamentals; 

Appendix B). 

The Avian Monitoring System (AIMS)13 is a database administered by the American Bird 

Conservancy that contains publicly available data on reported avian incidents involving 

 

13 http://www.abcbirds.org/abcprograms/policy/toxins/aims/aims/login.cfm 

O

H 3 C

C H 3

O

O

O

H 3C

H 3C C H 2

C H 3

C H 3

C O

H 3 C

C H 3

O

H O

H 3 C

O

H3C

CH3

O

HO

HOOC
17 

pesticides. Many of the incidents listed in this database are also in the EIIS. AIMS was also 

searched on October 22, 2014 and revealed no incidents to birds associated with spiromesifen. 

The aggregate incident database report, which typically reports non-major or aggregate 

incidences, was searched on November 26, 2014 and returned 4 plant incidences. 

Incidents may have also occurred due to spiromesifen exposures but may not have been reported 

due to various factors, such as a lack of reporting, or a lack of observation of effects. Therefore, 

the lack of incident reports does not necessarily indicate the absence of incidents. 

7. Exposure Pathways of Concern 

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

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

environment from a source to an ecological receptor. For an ecological pathway to be complete, 

it must include a source, a release mechanism, an environmental transport medium, a point of 

exposure for ecological receptors, and a feasible route of exposure. 

The environmental fate properties of spiromesifen indicate the following transport mechanisms 

for potential exposure to aquatic and terrestrial organisms: 

 Direct contact 

 Spray drift 

 Runoff 

 Ground water discharge 

 Consumption of contaminated food (sprayed food) 

 Root uptake (plants) 

 Bioaccumulation 

 

For terrestrial organisms, the major routes of exposure to spiromesifen are considered to be 

direct contact as a result of direct application and spray drift and dietary ingestion of plants, 

animals, and/or soil that have spiromesifen residues as a result of direct application, spray drift, 

and runoff. 

For aquatic animal species, the major route of exposure to spiromesifen is considered to be 

uptake via the respiratory surface (gills) or the integument from surface water/sediment that has 

spiromesifen residues as a result of spray drift and runoff. Bioaccumulation is another potential 

exposure pathway for aquatic animal species due to the high log Kow of spiromesifen. 

For terrestrial (upland and semi-aquatic) non-target plants, the major routes of exposure to 

spiromesifen are considered to be direct contact as a result of direct application and spray drift 

and root uptake via treated soil or soil contaminated via spray drift and runoff. 

For aquatic plants, the major routes of exposure to spiromesifen are considered to be uptake from 

surface water/sediment containing spiromesifen residues as a result of spray drift, runoff, and 

leaching to ground water from soil where such ground water is used for irrigation purposes. 
18 

Modeling results using STIR indicate that exposure to spiromesifen through inhalation is not 

likely to be significant for birds or mammals (no LOC exceedances are expected via this 

potential route of exposure; Appendix C). 

8. Analysis Plan 

In order to address the risks, the potential for adverse effects on the environment is estimated. 

The uses, environmental fate, and ecological effects of spiromesifen are characterized and 

integrated to assess the risks. This is accomplished using a risk quotient (ratio of exposure 

concentration to effects concentration) approach. Although risk is often defined as the likelihood 

and magnitude of adverse ecological effects, the risk quotient-based approach does not provide a 

quantitative estimate of likelihood and/or magnitude of an adverse effect. However, as outlined 

in the Overview Document (USEPA, 2004), the likelihood of effects to individual organisms 

from particular uses of spiromesifen is estimated using the probit dose-response slope and either 

the level of concern (discussed below) or actual calculated risk quotient value. 

This analysis plan may be revised depending upon the information submitted by the public in 

response to the opening of the Registration Review docket for spiromesifen. 

a. Stressors of Concern 

i. Ecological Risk Assessment 

Spiromesifen only will be considered in the ecological risk assessment as available data on the 

primary degradate indicate that it is practically nontoxic on an acute exposure basis. Due to 

limited data on degradates they will be characterized as an uncertainty. There are currently no 

ecotoxicity data for terrestrial wildlife exposed to spiromesifen degradates. ECOSAR results of 

the two major degradates, BSN2060-enol and BSN2060-4-carboxy, indicated they were less 

toxic than parent spiromesifen by more than an order of magnitude. Therefore, the BSN2060-

enol and BSN2060-4-carboxy degradates will not be considered a stressors of concern in the 

Registration Review ecological risk assessment. 

ii. Drinking Water 

The drinking water assessments conducted to support the Registration Review human health risk 

assessments of spiromesifen will incorporate model estimates of residues of concern, which are 

parent compound, BSN2060-enol and BSN2060-4-carboxy, in surface and ground water source 

drinking water. These degradates are mobile and more persistent than the parent compound. 

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. 
19 

i. Available Monitoring Data 

The Agency is not aware of surface or ground water monitoring conducted by federal and state 

agencies. However, if monitoring data of spiromesifen become available, they will be considered 

in the assessment. 

c. Measures of Effect 

Toxicity data presented in Section 6 of this problem formulation will be used to calculate risk 

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

meeting the standards established by the Agency prior to conduct of the risk assessment will also 

be considered. The open literature studies are identified using EPA’s ECOTOXicology database 

(ECOTOX)14, which employs a literature search engine for locating chemical toxicity data for 

aquatic life, terrestrial plants, and wildlife. The evaluation of both sources of data can also 

provide insight into the direct and indirect effects of pesticides on biotic communities from loss 

of species that are sensitive to the chemicals and from changes in structure and functional 

characteristics of the affected communities. 

9. Endangered Species Assessments 

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

Agency will evaluate risks to listed species from registered uses of pesticides in Registration 

Review. The process for evaluating potential risks to listed species is further described at 

http://www.epa.gov/oppfead1/endanger/litstatus/riskasses.htm. 

10. Endocrine Disruptor Screening Program (EDSP) 

Spiromesifen was not included in the first or second group of chemicals for which orders to 

conduct Tier 1 EDSP testing were issued. For additional information the EDSP program, visit 

http://www.epa.gov/endo/. 

11. Preliminary Identification of Data Gaps 

a. Environmental Fate 

Table 4 identifies environmental fate studies, by master record identification (MRID) number, 

that provide data for each guideline requirement, as well as study classifications and whether or 

not further data are needed in order to support risk assessment. 

 

14 http://cfpub.epa.gov/ecotox/
20 

Table 4. Submitted Environmental Fate Data for Spiromesifen. 

OCSPP 

Guideline Data Requirement Submitted 

MRIDs 

Study 

Classification

Are additional 

data needed to 

conduct risk 

assessment? 

Justification 

835.2120 Hydrolysis 45819734 Acceptable No --

835.2370 Aqueous Photolysis 45819811 Acceptable No --

835.2410 Soil Photolysis 45819801 Supplemental No --

835.4100 Aerobic Soil 

Metabolism 

45819808 Supplemental 

45819824 Acceptable No -- 

45819825 Acceptable 

835.4200 Anaerobic Soil 

Metabolism Not submitted No -- 

835.4300 Aerobic Aquatic 

Metabolism 

45819803 

45819804 Supplemental No -- 

835.4400 Anaerobic Aquatic 

Metabolism 45819802 Supplemental No -- 

835.1230 

Adsorption/ 

Desorption batch 

equilibrium 

45819806 Supplemental 

No -- 

45819810 Supplemental 

45819820 Invalid 

45819819 Acceptable 

45819821 Acceptable 

835.1240 Aged Column 

Leaching 45819826 Supplemental No -- 

835.1410 Lab Volatility Not submitted No -- 

835.6100 Terrestrial; Field 

Dissipation 

45819805 Acceptable 

No -- 45819807 Acceptable 

45819812 Acceptable 

45819813 Acceptable 

835.6200 Aquatic Field 

Dissipation Not submitted No -- 

835.1730 Bioaccumulation in 

Fish 45819720 Acceptable No -- 

850.6100 

Environmental 

Chemistry Methods 

(ECM) and 

Independent 

Laboratory 

Validation (ILV) in 

soil 

Not submitted Yes 

This is a standard data 

requirement for field 

dissipation and ground 

water monitoring studies. 

ECM and associated ILV 

are not available for the 

method used in the field 

dissipation studies, though 

this is a requirement for 

acceptance of such 

studies. 
21 

OCSPP 

Guideline Data Requirement Submitted 

MRIDs 

Study 

Classification

Are additional 

data needed to 

conduct risk 

assessment? 

Justification 

850.6100 

Environmental 

Chemistry Methods 

(ECM) and 

Independent 

Laboratory 

Validation (ILV) in 

water 

Not submitted Yes 

This is a standard data 

requirement for field 

dissipation and ground 

water monitoring studies. 

ECM and associated ILV 

are not available for the 

method used in the field 

dissipation studies, though 

this is a requirement for 

acceptance of such 

studies. 

835.4399 Ground water-small 

prospective 47133102 Supplemental No -- 

b. Effects 

Table 5 identifies ecological effects studies with spiromesifen, by MRID for each guideline 

requirement, as well as study classifications and whether or not additional data are needed in 

order to support risk assessment. Rationales for any additional data are also presented. For nonguideline studies, data justification tables follow Table 5. 

Table 5. Submitted Ecological Effects Data for Spiromesifen (TGAI=technical grade active ingredient; 

TEP=technical end product). 

OCSPP 

Guideline Species Tested Submitted MRIDs 

Study 

Classifications

Are additional 

data needed to 

conduct risk 

assessment? 

Justification 

Aquatic Organisms 

850.1075 

Freshwater fish 

acute toxicity 

Rainbow trout 

Oncorhynchus 

mykiss

458197-07 Supplemental No -- 

Fathead Minnow 

Pimephales 

promelas

458197-09 Supplemental No -- 

Rainbow trout 

O. mykiss (TEP) 458197-25 Supplemental No -- 

Bluegill sunfish 

Lepomis 

macrochirus 

(TEP) 

458197-26 Supplemental No -- 

850.1075 

Saltwater fish 

acute toxicity 

Sheepshead 

minnow 

Cyprinodon 

variegatus

458197-08 Supplemental No -- 
22 

OCSPP 

Guideline Species Tested Submitted MRIDs 

Study 

Classifications

Are additional 

data needed to 

conduct risk 

assessment? 

Justification 

850.1010 

Freshwater 

invertebrate acute 

toxicity 

Water flea 

Daphnia magna 458545-12 Supplemental No -- 

Water flea 

D. magna (TEP) 458197-29 Supplemental No -- 

850.1025 

Estuarine/marine 

mollusk acute 

toxicity 

Eastern oyster 

Crassostrea 

virginica

458197-15 Supplemental No -- 

850.1035 

Saltwater 

invertebrates 

acute toxicity 

Mysid shrimp 

Americamysis 

bahia

458197-02 Supplemental No -- 

850.1400 

Freshwater fish 

early-life stage 

toxicity test 

Rainbow trout 

O. mykiss 458197-27 Supplemental No -- 

850.1400 

Saltwater fish 

early-life stage 

toxicity test 

-- None -- Yes 

No data are available with 

which to assess chronic risk 

to estuarine/marine fish. Data 

are recommended due to 

spiromesifen’s outdoor use 

patterns, chronic effects to 

freshwater fish, potential for 

bioaccumulation, and a halflife in water >4 days. The 

sheepshead minnow 

(Cyprinodon variegatus) is a 

recommended test species. 

850.1500 

Fish full life 

cycle test 

Fathead Minnow 

Pimephales 

promelas

458197-12 Supplemental No -- 

850.1300 

Chronic toxicity 

to freshwater 

invertebrates 

Water flea 

D. magna 458197-05 Supplemental No -- 

Water flea 

D. magna (TEP) 458197-10 Supplemental No

Submitted data with 

spiromesifen formulated 

product (BSN 2060 240 SC; 

23.1% ai) showed a nondefinitive endpoint less (<) 

than the lowest concentration 

tested. Therefore, a chronic 

test is needed to characterize 

the toxicity of the formulated 

product to D. magna. 

Water flea 

D. magna (-enol 

degradate) 

458197-01 Acceptable No -- 
23 

OCSPP 

Guideline Species Tested Submitted MRIDs 

Study 

Classifications

Are additional 

data needed to 

conduct risk 

assessment? 

Justification 

850.1350 

Aquatic 

invertebrate lifecycle test 

Mysid shrimp 

Americamysis 

bahia

458197-11 Acceptable No -- 

Benthic Invertebrates 

OECD 218 

Spiked sediment 

chronic 

freshwater 

invertebrate 

Midge 

Chironomus 

riparius 

471331-03 Acceptable No 

Sediment toxicity testing is 

recommended because 

spiromesifen is expected to 

partition to sediment 

(Koc=45,900-106,000 L/kgoc; 

Kow = 3.6x104

). Chronic 

studies are recommended due 

to the aerobic soil metabolism 

half-life of >10 days 

(anaerobic aquatic 

metabolism half-life = 18 

days). 

Studies of one additional 

freshwater species (Hyalella 

azteca) and one 

estuarine/marine species 

(Leptocheirus plumulosus) 

are recommended.

OECD 219 

Spiked water 

chronic 

freshwater 

invertebrate 

Midge 

Chironomus 

riparius 

458197-28 Supplemental No 

Non-guideline 

Whole sediment 

chronic 

freshwater 

invertebrate15

-- None -- Yes 

Non-guideline 

Whole sediment 

chronic 

estuarine/marine 

invertebrate16

-- None -- Yes 

Aquatic Plants and Algae 

850.4400 

Aquatic plant 

toxicity, Lemna 

gibba 

Duckweed 

(Lemna gibba) 458197-14 Acceptable No -- 

 

15 An alternative approach for whole sediment chronic studies for Hyalella azteca may be considered. Sediment 

toxicity testing could first be conducted using the subchronic (10-d) sediment toxicity test guidelines (OSCPP 

850.1735). Pending a comparison of estimated environmental concentrations (EEC) in sediment and pore water 

with toxicity results from the 10-d sediment toxicity studies, the need for one or more chronic sediment toxicity 

studies would be determined. 16 An alternative approach for whole sediment chronic studies for Leptocheirus plumulosus may be considered. 

Sediment toxicity testing could first be conducted using the subchronic (10-d) sediment toxicity test guidelines 

(OSCPP 850.1740). Pending a comparison of estimated environmental concentrations (EEC) in sediment and pore 

water with toxicity results from the 10-d sediment toxicity studies, the need for one or more chronic sediment 

toxicity studies would be determined. 
24 

OCSPP 

Guideline Species Tested Submitted MRIDs 

Study 

Classifications

Are additional 

data needed to 

conduct risk 

assessment? 

Justification 

850.4500 

Algal toxicity 

Green algae 

Pseudokirchnerie

lla subcapitata

458197-03 Acceptable Yes 

Toxicity data on a marine 

diatom and a freshwater 

diatom are needed for 

evaluation of risk to 

nonvascular aquatic plants. 

The marine diatom 

Skeletonema costatum and 

freshwater diatom Navicula 

pelliculosa are recommended 

test species. 

850.4550 

Aquatic plant 

growth: 

cyanobacteria 

-- None -- Yes 

Toxicity data on 

cyanobacteria are needed for 

evaluation of risk to 

nonvascular aquatic plants. 

Cyanobacteria (Anabaena 

flos-aquae) are recommended 

for this test. 

Terrestrial Organisms 

850.2100 

Avian acute oral 

toxicity 

Bobwhite Quail 

Colinus 

virginianus

458197-23 Acceptable No 

No data have been submitted 

to assess effects on passerine 

species. However, the lack of 

acute or sub-acute effects on 

the tested species indicates 

that additional data are 

unlikely to impact the risk 

assessment. 

850.2200 

Avian dietary 

toxicity 

Bobwhite Quail 

C. virginianus 458197-21 Supplemental No -- 

Mallard Duck 

Anas 

platyrhynchos

458197-22 Acceptable No -- 

850.2300 

Avian 

reproduction test 

Bobwhite Quail 

C. virginianus

458197-24 Supplemental 

No -- 

471331-01 Acceptable 

Mallard Duck 

A. platyrhynchos

458196-26 Supplemental 

No -- 

471422-01 Acceptable 

850.3020 

Adult honey bee 

acute contact 

toxicity 

Honey Bee 

Apis mellifera 458197-18 Acceptable No -- 

Honey Bee 

A. mellifera 

(TEP) 

458197-17 Acceptable No -- 

Non-guideline 

Adult honey bee 

Honey Bee 

A. mellifera 458197-18 Supplemental No -- 
25 

OCSPP 

Guideline Species Tested Submitted MRIDs 

Study 

Classifications

Are additional 

data needed to 

conduct risk 

assessment? 

Justification 

acute oral 

toxicity 

TGAI 

Honey bee 

(A. mellifera) 458197-17 Supplemental No -- 

Non-Guideline 

acute larval 

toxicity 

TGAI 

Honey bee (Apis 

mellifera)

None -- Yes 

Although data indicate 

spiromesifen is practically 

non-toxic to young adult 

honey bees on an acute 

exposure basis, no data are 

available on the acute and 

chronic toxicity for honey bee 

larvae. Therefore, data are 

needed on acute and chronic 

toxicity of TGAI to honey bee 

larvae1

. 

Non-Guideline 

chronic larval 

toxicity 

TGAI 

Honey bee (Apis 

mellifera) 

Non-guideline 

adult chronic oral 

(10-day) toxicity 

TGAI 

Honey bee (Apis 

mellifera) None -- Yes

This test is needed to evaluate 

the chronic toxicity of 

spiromesifen to adult honey 

bees1

. 

Special study17

(Tier II) 

Semi-field 

Testing 

TEP 

Honey bee (Apis 

mellifera) 

None -- Yes2

 Insect pollinators may be 

exposed if these compounds 

are applied at bloom or when 

bees are foraging on extrafloral nectaries. Therefore, 

residues may be present in 

pollen and/or nectar and 

represent a route of exposure 

for bees through both contact 

and ingestion. Field testing 

conducted with TEP. 

Special study 

(Tier II)18

Field trial of 

residues in pollen 

and nectar with 

TEP 

 Honey bee (Apis 

mellifera)

850.3040 

Field testing for 

pollinators 

Honey Bee 

A. mellifera 

(Greenhouse) 

480335-01 Supplemental Yes2

 -- 

Honey Bee 

A. mellifera

(Cotton field) 

473444-01 Supplemental Yes2 -- 

Honey Bee 

A. mellifera

(Melon field) 

479172-01 Supplemental Yes2

 -- 

Terrestrial Plants 

850.4100 10 sp. (Tier I) 458197-06 Supplemental No -- 

 

17 Semi-field testing for pollinators with TEP would be needed based on the evaluation of the lower tier studies and 

the submitted field testing for pollinators studies. 

18 Field trial of residues of residues in pollen and nectar with TEP would be needed based on the evaluation of the 

lower tier studies and the submitted field testing for pollinators studies. 
26 

OCSPP 

Guideline Species Tested Submitted MRIDs 

Study 

Classifications

Are additional 

data needed to 

conduct risk 

assessment? 

Justification 

Seedling 

Emergence 

Ryegrass, onion, 

turnip (Tier II) 458196-29 Supplemental No -- 

850.4150 

Vegetative Vigor 

10 sp. (Tier I) 458197-06 Supplemental No -- 

Ryegrass, turnip 

(Tier II) 458196-29 Supplemental No -- 

1 Data on TEP is required if the formulation may enhance the toxicity of the chemical. 2

 Data requirement is dependent on a re-review of the submitted field studies with spiromesifen. 

TGAI=Technical Grade Active Ingredient; TEP=typical End-Use Product 

Guideline Number: None (Agency-Wide Guidelines found in USEPA 2000 and 200119)

Study Title: Whole sediment: Chronic toxicity, invertebrates freshwater and marine 

Rationale for Requiring the Data

Only one chronic sediment toxicity test for freshwater or marine invertebrates has been submitted to 

satisfy the Agency’s updated data requirements for outdoor uses in 40 CFR Part 158 (October 26, 

2007). Benthic organisms may be exposed residues in sediments as a result of run-off or spray drift 

from applications in terrestrial settings and based on the fate properties of spiromesifen. The following 

lines of evidence suggest the potential for exposure of benthic-dwelling organisms to spiromesifen: a 

Koc of 45,900-106,000 L/kgoc and Kow of 3.6x104

 indicate that spiromesifen is likely to partition to 

sediment in aquatic environments. For freshwater sediment testing, a test on an amphipod (e.g.,

Hyalella azteca) is preferred. The freshwater species, Hyalella and Chironomus, differ substantially in 

their ecological niche (i.e., epibenthic vs. infaunal species), life history, and phylogeny. For 

estuarine/marine sediment testing, tests on one amphipod species is requested (e.g., Leptocheirus 

plumulosus). 

In some situations, a tiered testing strategy may be considered for requesting chronic sediment toxicity 

testing. In this approach, sediment toxicity testing would first be conducted with the aforementioned 

species using the subchronic (10-d) sediment toxicity test guidelines (OSCPP 850.175 and 850.1740). 

Then, pending a comparison of estimated environmental concentrations (EEC) in sediment and pore 

water with toxicity results from the 10-d sediment toxicity studies, the need for one or more chronic 

sediment toxicity studies would be determined. This tiered testing approach has the potential 

advantage of reducing the number of chronic (life cycle) studies that would be needed when results of 

the 10-d (subchronic) tests in conjunction with sediment EECs indicate chronic testing is not likely to 

alter risk assessment conclusions. In some cases, however, this tiered testing approach may result in 

the conduct of both a 10-d (subchronic) and chronic (life cycle) study. Since no guideline is available 

for chronic testing, a protocol should be submitted for EPA review and approval prior to study 

initiation. 

 Practical Utility of the Data 

How will the data be used? 

Data from sediment toxicity studies will be used to estimate potential risks to benthic organisms 

associated with uses of spiromesifen. The data will reduce uncertainties associated with the current 

risk assessment for benthic species and will improve our understanding of the potential effects of 

 

19 Benthic invertebrate guidance: 

http://www.epa.gov/pesticides/science/efed/policy_guidance/team_authors/aquatic_biology_tech_team/ToxTesting_

EcoRiskAssessmentForBenthicInvertebrates.pdf
27 

spiromesifen on aquatic ecosystems. 

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

 If the data indicate that registered spiromesifen uses may pose a risk of adverse effects to non-target 

benthic organisms above the Agency Level of Concern, the Agency may explore decision options to 

mitigate this risk. The lack of these data will limit the flexibility the Agency and registrants have in 

coming into compliance with the Endangered Species Act, and could result in use restrictions for 

spiromesifen which may otherwise be avoided, or which are unnecessarily severe.

Study Title: Pollinator Acute 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 developing larvae and pupae may be exposed. Therefore, potential adverse 

effects to developing bees 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 toxicity of this compound to bee brood. 

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 

laboratory-based 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 be found at: http://www2.epa.gov/pollinator-protection/pollinator-risk-assessmentguidance. Additional guidance on larval honeybee toxicity test design can be found in OECD Test 

Guideline 237 (http://www.oecdilibrary.org/docserver/download/9713171e.pdf?expires=1422485600&id=id&accname=guest&checksu

m=D8E07C2B1DF77BF096C3B29F55BF86A7).

Practical Utility of the Data 

How will the data be used? 

The Tier 1 acute toxicity data on honeybee 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 invertebrates, including pollinators, and/or modify their designated critical 

habitat from acute 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 effects data for larvae are not available, risks to terrestrial insects from 

acute 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. 
28 

Study Title: 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 guidances 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. Although study design 

elements for the chronic 10-day oral toxicity test with honey bees are similar to the OECD TG 213 

acute oral toxicity test ( http://www.oecdilibrary.org/docserver/download/9721301e.pdf?expires=1422484908&id=id&accname=guest&checksu

m=C38495D2A570AC2216CFB1F223D24AA7), the proposed protocol for this study must be 

submitted for review and approval by EPA prior to initiating the test.

Practical Utility of the Data 

How will the data be used? 

The Tier 1 chronic 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 invertebrates, 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 1 tests. If chronic oral effects 

data for adults are not available, risks to terrestrial insects from chronic 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: Pollinator Chronic 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 exposure to pesticide residues. 

Available toxicity studies do not address possible chronic effects on brood (larvae and pupae) 
29 

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 I laboratory-based chronic 

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-riskassessment-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_Nove

mber_2013.pdf). Although study design elements for the chronic 21-day toxicity test with 

honey bee larvae have been drafted, the proposed protocol for this study must be submitted for 

review and approval by EPA prior to initiating the test. 

Practical Utility of the Data 

How will the data be used? 

The Tier 1 chronic 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 invertebrates, including insect pollinators, from chronic 

exposures to pesticides. These 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 effects 

data for larvae are not available, risks to terrestrial insects from chronic 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 nontarget 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 for Pollinators (tunnel or colony feeding 

studies) 

Rationale for Requiring the Data 

The decision to move to more refined effects testing and to transition from laboratory-based 

studies with individual bees (i.e., Tier 1) to colony-based studies (i.e., Tier 2 or Tier 3) 

depends on whether Tier 1 LOCs are exceeded, the availability of data, and the nature of the 

uncertainties that warrant further testing. The Tier 2 studies are typically considered “semi-
30 

field,” studies where small colonies are enclosed in tunnels, along with pesticide-treated crops. 

Tier 2 studies may also include feeding studies in which whole colonies are tested; however, 

the colonies are not confined to enclosures. The design of the Tier 2 tunnel study should be 

flexible in addressing the specific risks identified in the Tier 1 risk assessment for either foliar 

application, seed or soil treatments, or other exposure routes of concern with reasonable 

modifications. The registrant should consult the Agency on the design of the protocol prior to 

the initiation of the study. 

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 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 nontarget 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 Field trial of residues in pollen and nectar 

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. 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. 
31 

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

invertebrates with the honeybee. This guidance describes the tiered testing process and can be

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

Additional information on honey bee colony feeding studies can be found in the EPPO Guidance

170 (www.nationalbeeunit.com/downloadDocument.cfm?id=191). Although study design element

for the feeding study are available through the EPPO Guidance 170, EPA requires that the

proposed protocol for this study be submitted for review and approval by EPA prior to initiating

the test. 

Practical Utility of the Data 

How will the data be used? 

The data will be used to assess exposure and risk of spiromesifen to non-target listed and nonlisted terrestrial invertebrate species, including bee pollinators. These data would allow the 

Agency to refine the screening level risk assessment for pollinating bees. Exposure data is an 

integral part of determining the potential for risk to pollinating bees through direct exposure 

from their food sources. 

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

The Tier II colony-level data will be used to refine screening-level risk estimates derived using 

Tier I laboratory-based data on individual bees. The Tier II data will help to 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 III Full-Field Toxicity Testing for Pollinators 

Rationale for Requiring the Data 

Tier III studies are conditional on the outcome of the screening-level assessment (Tier 1) 

where acute and/or chronic risk levels of concern have been exceeded for terrestrial 

invertebrates and where Tier II studies either under semi-field tunnel conditions and/or feeding 

studies have indicated potential adverse effects at the colony level. Available toxicity studies 

from existing studies do not address possible effects and/or exposure to pesticide residues at 

the colony-level under actual pesticide use conditions and where specific uncertainties 

regarding the likelihood of exposure and/or effects remain. Full-field studies also provide an 

opportunity to measure residues in pollen and nectar as well as various matrices (beebread, 

honey, wax) within the colony to obtain a more realistic understanding of exposure. 

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

invertebrates with the honeybee. This guidance describes the tiered testing process and can be 

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

Additional information on honey bee colony studies under full-field conditions can be found in 

the OCSPP 850.3040 (http://www.regulations.gov/#!documentDetail;D=EPA-HQ-OPPT-2009-

0154-0018). Useful guidance is also available through OCSPP 850.2500 (Field Testing of 

Terrestrial Wildlife; 

http://www.epa.gov/ocspp/pubs/frs/publications/Test_Guidelines/series850.htm) Although 
32 

design elements for the full-field colony-level study are available through the 850.3040 and 

850.2500, the proposed protocol for this study must be submitted for review and approval by 

EPA prior to initiating the test; the protocol should attempt to address specific uncertainties 

identified in lower-tier studies.

Practical Utility of the Data 

How will the data be used? 

Tier III colony-level data will be used to further characterize potential risk to non-target 

organisms including listed and non-listed terrestrial social invertebrate species and to refine 

screening-level risk estimates that were based on individual bee responses. The full-field test 

is utilizes free-foraging bees and is designed to represent potential field-level exposure under 

actual use conditions and account for hive dynamics, which are not achievable from lower-tier 

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; residue data 

collected during field studies can be used to refine the screening-level risk estimates for 

beneficial terrestrial invertebrates. 

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 nontarget 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. 

12. References 

Arthur, E., L. Bowers, L. Buckelew, R. Christenson, V. Dorr, F. Duah, J. Fisher, T. Gould, I. Kelly, C. 

Lenz, J. Mixson, L. Russo, K. Shearer, V. Standart, and L. Stocky. 2003. Reduced Risk Rationale for the 

Use of Spiromesifen on Field Corn, Cotton, Vegetable and Fruit Crops, Cucurbit Vegetables, Fruiting 

Vegetables, Leafy Vegetables, Tuber Vegetables, Strawberry and Nursery, Greenhouse and Landscape 

Ornamentals. Bayer Crop Science, Research Triangle Park, NC 27709. 

Fischer, R. and J. Benet-Buchholz. 2002. Chemistry and stereochemistry of spirodiclofen (BAJ 2740). 

Pflanzenschutz-Nachrichten Bayer 55: 137-148. 

Food and Agriculture Organization of the United Nations. FAO Pesticide Disposal Series 8. Assessing 

Soil Contamination: A Reference Manual. Appendix 2. Parameters of pesticides that influence processes 

in the soil. Editorial Group, FAO Information Division: Rome, 2000. 

http://www.fao.org/docrep/003/X2570E/X2570E00.htm. 

Goring, C.A. I.; Laskowki; D.A., Hamaker, J.H.; and Meikle, R.W. 1975. Principles of pesticide 

degradation in soil. pp. 135-172 in (Haque, R. and Freed, V.H. eds.) Environmental dynamics of 

pesticides. Plenum Press, NY. 

USEPA 2000. Methods for Measuring the Toxicity and Bioaccumulation of Sediment-associated 

Contaminants with Freshwater Invertebrates. EPA 600/R-99/064. March. 
33 

USEPA 2001. Methods for Assessing the Chronic Toxicity of Marine and Estuarine Sediment-associated 

Contaminants with the Amphipod Leptocheirus plumulosus. EPA 600/R-01/020. March. 

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

U.S. Environmental Protection Agency. Endangered and Threatened Species Effects Determinations. 

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

Available online at http://www.epa.gov/oppfead1/endanger/consultation/ecorisk-overview.pdf. 

USEPA 2005. Young, D. and Steeger, T. Environmental Fate and Ecological Risk Assessment for the 

Registration of Spiromesifen. DP Barcode 289953. U.S. Environmental Protection Agency, Office of 

Chemical Safety and Pesticides Program, Environmental Fate and Effects Division. May 10, 2005. 

USEPA 2010a. Clock- Rust, M. and Orrick, G. Environmental Fate and Ecological Risk Assessment for 

Proposed New Uses of Spiromesifen on Wheat, Sorghum, Dry Peas, Mint, and the Leafy Petioles Crop 

Subgroup (4B). DP Barcode 368560. U.S. Environmental Protection Agency, Office of Chemical Safety 

and Pesticides Program, Environmental Fate and Effects Division. Memorandum to the Registration 

Division. June 7, 2010. 

USEPA 2010b. Orrick, G. and Sutton, C. Drinking Water Exposure Assessment for Proposed New Uses 

of Spiromesifen on Wheat, Sorghum, Dry Peas, Mint, and the Leafy Petioles Crop Subgroup (4B). DP 

Barcode 368558, 373896, 374900. U.S. Environmental Protection Agency, Office of Chemical Safety and 

Pesticides Program, Environmental Fate and Effects Division. Memorandum to the Registration Division. 

March 25, 2010. 

USEPA 2011. Clock- Rust, M. and Steeger, T. Response to Registrant Submissions on Systemicity of 

Keto-enols Spiromesifen, Spirodiclofen and Spirotetramat. DP Barcodes 385088, 384526. U.S. 

Environmental Protection Agency, Office of Chemical Safety and Pesticides Program, Environmental 

Fate and Effects Division. Memorandum to the Registration Division. April 4, 2011.

USEPA 2014 BEAD Chemical Profile (BCP) for Registration Review: Spiromesifen (PC Code: 

024875). Memorandum from Biological and Economic Analysis Division to Pesticide Re-evaluation 

Division. October 30. 
34 

13. Appendix A. Submitted Environmental Fate and Effects Studies of Spiromesifen 

PC 024875- SUBMITTED FATE STUDIES (as of 10/28/14) 

161-1 Hydrolysis 

MRID Citation Reference 

45819734 Arthur, E.; Shepherd, J.; Parker, G. (2001) Hydrolysis of BSN2060 in pH 4,7, 

and 9 Sterile Aqueous Buffer Solutions at 25 and 50 (Degrees) C: Lab 

Project Number: BS072401: 109481. Unpublished study prepared by Bayer 

Corporation. 116 p. 

46556601 Arthur, E.; Shepherd, J.; Parker, G. (2005) Hydrolysis of BSN2060 in pH 4, 

7, and 9 Sterile Aqueous Buffer Solutions at 25 and 50 Degrees Celsius. 

Project Number: 109481/1, BS072401. Unpublished study prepared by Bayer 

Cropscience LP. 116 p.

161-2 Photodegradation-water 

45819809 Shepherd, J.; Arthur, E. (2001) Aqueous Photolysis of (Cyclopentyl-1-(Carbon 

14)) BSN2060-Enol in pH 7 Sterile Buffer Solution at 25 (Degrees) C: Lab Project 

Number: BS082402: 110596. Unpublished study prepared by Bayer Corporation. 

71 p. 

45819811 Arthur, E.; Shepherd, J. (2001) Aqueous Photolysis of BSN2060 

(Dihydrofuranone-3-(Carbon 14)) in pH 4 Sterile Aqueous Buffer at 25 (Degrees) 
35 

C: Lab Project Number: BS082401: 110962. Unpublished study prepared by Bayer 

Corporation. 92 p. 

45819823 Hellpointer, E. (2001) Determination of the Quantum Yield and Assessment of the 

Environmental Half-Life of the Direct Photodegradation in Water of BSN2060: 

Lab Project Number: M 143 0944-5: MR-120/01: HPO-216. Unpublished study 

prepared by Bayer AG. 34 p. 

46059301 Arthur, E.; Shepherd, J. (2003) Aqueous Photolysis of BSN2060 

[Dihydrofuranone-3-(Carbon 14)] in pH 4 Sterile Aqueous Buffer at 25 Degrees C. 

Project Number: 110962/1, BS082401. Unpublished study prepared by Bayer 

Corp. 92 p.

45819818 Fisher, J.; Sabbagh, G. (2002) BSN2060 Aqueous Photolysis Exposure 

Assessment: Lab Project Number: 220262: 110962: 110044. Unpublished study 

prepared by Bayer Corporation. 19 p. 

161-3 Photodegradation-soil 

45819801 Shepherd, J.; Arthur, E.; Ripperger, R. (2001) Soil Photolysis of (Dihydrofuranone-3-

(Carbon 14)) BSN2060: Lab Project Number: BS082101: 11028. Unpublished study 

prepared by Bayer Corporation. 90 p. 

161-4 Photodegradation-air 

45819822 Hellpointer, E. (1999) Calculation of the Chemical Lifetime of BSN2060 in the 

Troposphere: Lab Project Number: HP0169: MR-090/99. Unpublished study 

prepared by Bayer AG. 12 p. 

162-1 Aerobic soil metabolism 

45819808 Ripperger, R.; Hall, L. (2001) Aerobic Soil Metabolism of (Cyclopentyl-1-(Carbon 

14)) BSN2060 in Fresno, California Soil: Lab Project Number: BS042101: 110450. 

Unpublished study prepared by Bayer Corporation. 97 p. 

45819824 Brumhard, B.; Elke, K. (2001) Aerobic Degradation and Metabolism of 

(Dihydrofuranone-3-(Carbon 14)) BSN2060 in Soils: Lab Project Number: 

M1250959-1: MR-229/01. Unpublished study prepared by Bayer AG. 101 p. 

45819825 Baczinski, P. (2001) Aerobic Degradation and Metabolism of (Phenyl-UL-(Carbon 

14)) BSN2060 in Soil: Lab Project Number: M 1251034-6: MR-361/00. 

Unpublished study prepared by Bayer AG. 64 p. 

45819827 Schad, T. (2001) Calculation of Degradation Rates of BSN2060 and its Metabolites 

BSN2060-Enol and BSN2060-4-Carboxy Based on Aerobic Soil Degradation 

Studies: Lab Project Number: MR-501/01: P668 01 6778. Unpublished study 

prepared by Bayer AG. 27 p. 

 

162-3 Anaerobic aquatic metabolism. 

45819802 Arthur, E.; Desmarteau, D.; Wujcik, C.; et. al. (2001) Anaerobic Aquatic Metabolism 
36 

of (Dihydrofuranone-3-(Carbon 14)) BSN2060 in a Fresno, California, Water and 

Sediment System: Lab Project Number: BS042401: 110039. Unpublished study 

prepared by Bayer Corporation. 123 p. 

162-4 Aerobic aquatic metabolism. 

45819803 Desmarteau, D.; Wujcik, C.; Arthur, E. (2001) Aerobic Aquatic Metabolism of 

(Dihydrofuranone-3-(Carbon 14)) BSN2060 in a Fresno, California, Water and 

Sediment System: Lab Project Number: BS042402: 110044. Unpublished study 

prepared by Bayer Corporation, ABC Laboratories and Agvise Laboratories, Inc. 141 

p. 

45819804 Desmarteau, D.; Wujcik, C.; Arthur, E. (2001) Aerobic Aquatic Metabolism of 

(Dihydrofuranone-3-(Carbon 14)) BSN2060 in a German Water and Sediment 

System: Lab Project Number: BS042403: 110045. Unpublished study prepared by 

Bayer Corporation. 140 p. 

163-1 Leach/adsorption/desorption 

45819735 Malekani, K.; Ripperger, R. (2000) Leaching Potential of Aged (Dihydrofuranon-3-

(Carbon-14))BSN2060 Residues in Hesperia Sandy Loam: Lab Project Number: 

109483: 99-B-166: BS092101. Unpublished study prepared by Bayer Corporation. 51 

p. 

45819806 Arthur, E.; Shepherd, J. (2002) Mobility Determination of BSN2060 by Soil ThinLayer Chromatography in Four Soils: Lab Project Number: BS182101: 110342. 

Unpublished study prepared by Bayer Corporation. 54 p. 

45819810 Desmarteau, D.; Aga, S. (2001) Estimation of the Adsorption Coefficients (Koc) of 

BSN2060, BSN2060-Cyclobutyl and BSN2060-Enol Photoisomers on Soil Using 

High Performance Liquid Chromatography (HPLC): Lab Project Number: 

BS184001: 110750. Unpublished study prepared by Bayer Corporation. 25 p. 

45819819 Burhenne, J. (1998) Adsorption-Desorption of BSN 0546 (Tetronic Acid BSN 2060) 

on Soils: Lab Project Number: MO-99-001080: IM-1978: 1310010-6. Unpublished 

study prepared by University of Kassel. 41 p. 

45819820 Hein, W. (1999) Adsorption-Desorption of (Dihydrofuranon-3-(Carbon 14)) BSN 

2060 on Four Different Soils: Lab Project Number: BAY 32: IM-1981. Unpublished 

study prepared by Staatliche Lehr- und Forschungsanstalt. 21 p. 

45819821 Hellpointer, E. (2001) Adsorption/Desorption of (Carbon 14)-

BSN2060-4-Carboxy on Four Different Soils: Lab Project Number: 

BAY51: IM-1991. Unpublished study prepared by Staatliche Lehr-und 

Forschungsanstalt. 28 p. 

45819826 Baczinski, P. (2001) Soil Column Leaching of BSN2060: Lab Project 

Number: M 1321075-9: MR-362/00. Unpublished study prepared by 

Bayer AG. 113 p. 

164-1 Terrestrial field dissipation 

45819415 Leimkuehler, W.; Ripperger, R. (2002) Analytical Method for the Determination of 

BSN2060 and Metabolite Residues in Soil: Lab Project Number: 110478. 
37 

Unpublished study prepared by Bayer Corporation. 37 p. {OPPTS 850.7100} 

45819805 Dyer, D.; Wood, S.; Leimkuehler, W.; et. al. (2002) Terrestrial Field Dissipation of 

BSN2060 on Texas Soil, 1999: Lab Project Number: BS022101: 110327. 

Unpublished study prepared by Bayer Corporation, A & L Great Lakes Laboratories, 

Inc. and South Texas Ag Research. 100 p. 

45819807 Dyer, D.; Wood, S.; Leimkuehler, W.; et al. (2002) Terrestrial Field Dissipation of 

BSN2060 on California Soil, 1999: Lab Project Number: BS022102: 110348. 

Unpublished study prepared by Bayer Corporation, A & L Great Lakes Laboratories, 

Inc. and Bayer Research Farm. 96 p. 

45819812 Dyer, D.; Wood, S.; Leimkuehler, W.; et al. (2002) Terrestrial Field Dissipation of 

BSN2060 on Florida Soil, 1999: Lab Project Number: 110978: BS022103. 

Unpublished study prepared by Bayer Corporation, A & L Great Lakes Laboratories 

and Weed Systems Inc. 97 p. 

45819813 Dyer, D.; Wood, S.; Leimkuehler, W.; et al. (2002) Terrestrial Field Dissipation of 

BSN2060 on Florida Soil, 1999: Lab Project Number: BS022104: 110986. 

Unpublished study prepared by Bayer Corporation, A & L Great Lakes Laboratories 

and Qualls Agricultural Laboratory. 89 p. 

46059302 Arthur, E. (2003) Fate of BSN2060 in the Environment: Summary. Project Number: 

200152/1. Unpublished study prepared by Bayer Corp. 68 p. 

165-1 Confined rotational crop 

45819409 Aikens, P. (2002) BSN 2060: Accumulation in Confined Rotational Crops: Lab 

Project Number: BAG 291: 200337: BAG 291/003753. Unpublished study 

prepared by Huntingdon Life Sciences, Ltd. 127 p. {OPPTS 860.1850} 

45819503 Lemke, V. (2002) BSN 2060 240 SC--Magnitude of the Residue in Wheat 

(Rotational Crop Tolerance): Lab Project Number: BS19WH01: 200185: BS126-

00R. Unpublished study prepared by Bayer Corp. and Battelle--AgriFood. 597 p. 

{OPPTS 860.1900} 

45819504 Lemke, V. (2002) BSN 2060 240 SC--Magnitude of the Residue in Barley 

(Rotational Crop Tolerance): Lab Project Number: BS19BA01: 200186: BS147-

00R. Unpublished study prepared by Bayer Corp. and Battelle--AgriFood. 427 p. 

{OPPTS 860.1900} 

165-2 Field rotational crop 

45819424 Beedle, E. (2002) BSN 2060 240 SC--Magnitude of the Residue in Alfalfa 

(Rotatational Crop Tolerance): Lab Project Number: BS19AL01: 200112: BS114-

00R. Unpublished study prepared by Bayer CropScience and Battelle--AgriFood. 

311 p. {OPPTS 860.1900} 

45819428 Harbin, A. (2002) BSN 2060 240 SC--Magnitude of the Residue in Sugar Beets 

(Rotational Crop Tolerance): Lab Project Number: BS19SB01: 200161: BS163-

00R. Unpublished study prepared by Bayer Corporation and Battelle-AgriFood. 

316 p. {OPPTS 860.1900} 

165-4 Bioaccumulation in fish 
38 

45819720 Caldwell, E. (2001) (Carbon 14)-(BSN 2060)--Bioconcentration in Rainbow 

Trout: Lab Project Number: BAG 317: BAG 317/994679. Unpublished study 

prepared by Huntingdon Life Sciences Ltd. 134 p. {OPPTS 850.1730} 

166-1 Ground water-small prospective 

835.4300 

47133102 Shepherd, J.; Allan, J. (2007) Fate of Spiromesifen-Dihydrofuranone-3-[14-

Carbon] Applied to a Laboratory Sediment Followed by Flooding and 

Incubated for 28 Days. Project Number: MEBSX019. Unpublished study 

prepared by Bayer CropScience LP. 52 p. 

*Conducted in conjunction with Chironomid 28 Day study 

Non-Guideline Study Selections 

45819430 Bauer, M. (2002) Independent Laboratory Validation of "Determination of 

BSN 2060 and Four Metabolites in Soil by LC-MS/MS": Lab Project Number: 

AG010018: BS112101: 200168. Unpublished study prepared by Bayer 

Corporation. 97 p. {OPPTS 850.7100} 

45819432 Leimkuehler, W.; Woodard, D. (2002) Analytical Method for the 

Determination of BSN2060 and BSN2060-Enol in Water: Lab Project Number: 

200173. Unpublished study prepared by Bayer Corporation. 23 p. {OPPTS 

860.1400} 

45819527 Moore, K. (2001) A Liquid Chromatographic Method for the Determination of 

BSN 2060 in Dose Preparations: Lab Project Number: 00-Q99-BG: 110219. 

Unpublished study prepared by Bayer Corp. 13 p. 

 

45819814 Fisher, J.; Sabbagh, G. (2002) Estimation of Soil Adsorption Koc for 

BSN2060: Lab Project Number: 111039. Unpublished study prepared by Bayer 

Corporation. 24 p. 

 

46059302 Arthur, E. (2003) Fate of BSN2060 in the Environment: Summary. Project 

Number: 200152/1. Unpublished study prepared by Bayer Corp. 68 p. 

SUBMITTED EFFECT STUDIES (as of 11/5/2014) 

71-1 Avian Single Dose Oral Toxicity 

MRID Citation Reference 

45819723 2021802 Barfknecht, R. (1999) BSN 2060 Techn. a.i.: Acute Oral Toxicity for Bobwhite Quail (Colinus 

virginianus): Lab Project Number: BAR/LD026: E 292 1540-3. Unpublished study prepared 

by Bayer Ag Crop Protection. 35 p. 

71-2 850.2200 Avian Dietary Toxicity 
39 

MRID Citation Reference 

45819721 2021800 Barfknecht, R. (2001) BSN 2060 Techn.: 5-Day-Dietary LC50 to Bobwhite Quail (Colinus 

virginianus): Lab Project Number: BAR/LC004: E 296 1507-0. Unpublished study prepared 

by Bayer Ag Crop Protection. 39 p. 

45819722 2021801 Barfknecht, R. (2001) BSN 2060 Techn.: 5-Day-Dietary LC50 to Mallard Duck (Anas 

platyrhynchos): Lab Project Number: BAR/LC008: E 297 1506-0. Unpublished study 

prepared by Bayer Ag Crop Protection. 39 p. 

71-4 850.2300 Avian Reproduction 

MRID Citation Reference 

45819626 2021778 Mach, J.; Medlicott, B. (2001) Avian Reproduction Study with BSN 2060 Technical in Mallard 

Ducks (Anas platyrhynchos): Amended Final Report: Lab Project Number: BS740801: 

00021: 110119. Unpublished study prepared by Genesis Laboratories, Inc. 156 p. {OPPTS 

850.2300} 

45819724 2021803 Barfknecht, R. (2001) BSN 2060 Techn. a.i.: Effects of a Subchronic Dietary Exposure to the 

Northern Bobwhite Quail Including Effects on Reproduction and Behavior: Lab Project 

Number: E 298 1505-0: BAR/REP003. Unpublished study prepared by Bayer Ag Crop 

Protection. 112 p. 

47133101 2066626 Barfknecht, R. (2007) Effects of a Subchronical Dietary Exposure to Northern Bobwhite 

Quails Including Effects on Reproduction and Behaviour. Project Number: E/205/3146/1, 

BAR/REP012. Unpublished study prepared by Bayer Ag. 260 p. 

47142201 2066628 Christ, M.; Lam, C. (2007) Effect of Technical BSN 2060 (Spiromesifen) on Mallard 

Reproduction. Project Number: EBBSX044. Unpublished study prepared by Bayer 

CropScience. 73 p. 

46260001 Registrant 

suggested 

results 

Bowers, L.; Fischer, D. (2004) Proposed NOEC and LOEC for the Avian Reproduction 

Study: "BSN 2060 Technical: Effects of a Subchronic Dietary Exposure to the Northern 

Bobwhite Quail Including Effects on Reproduction and Behavior". Project Number: 201034. 

Unpublished study prepared by Bayer Corp. 9 p. 

46260002 Registrant 

suggested 

results 

Bowers, L.; Fischer, D. (2004) Proposed NOEC and LOEC for the Avian Reproduction 

Study: "Avian Reproduction Study with BSN 2060 Technical in Mallard Ducks (Anas 

platyrhynchos)". Project Number: 201033. Unpublished study prepared by Bayer Corp. 9 p. 

72-1 Acute Toxicity to Freshwater Fish 

MRID Citation Reference 

45819628 2021780 Peither, A. (2000) Acute Toxicity of BSN 2060-Enol to Rainbow Trout (Oncorhynchus 

mykiss): Lab Project Number: 737392: 110324. Unpublished study prepared by RCC Ltd. 37 

p. {OPPTS 850.1075} 

45819704 2021786 Hancock, G.; Lam, C. (2002) Acute Toxicity of BSN 2060 Technical to the Bluegill (Lepomis 

macrochirus) Under Flow-Through Conditions: Lab Project Number: BS810301: 110408. 

Unpublished study prepared by Bayer Corporation. 33 p. 

45819707 2021789 Kern, M.; Hall, A.; Lam, C. (2002) Acute Toxicity of BSN 2060 Technical to the Rainbow 

Trout (Oncorhynchus mykiss) Under Flow-through Conditions: Lab Project Number: 

BS812201: 110970. Unpublished study prepared by Bayer Corporation. 34 p. 

45819709 2021791 Hancock, G.; Lam, C. (2002) Acute Toxicity of BSN 2060 Technical to the Fathead Minnow 

(Pimephales promelas) Under Flow-through Conditions: Lab Project Number: BS811201: 

110975. Unpublished study prepared by Bayer Corporation. 32 p. 

45819725 2021804 Dorgerloh, M. (1999) BSN 2060 SC 240--Acute Toxicity (96 Hours) to Rainbow Trout 
40 

2025442 (Oncorhynchus mykiss) in a Static Test: Lab Project Number: DOM 99024: E 250 1546-3: 

00482. Unpublished study prepared by Bayer Ag Crop Protection. 45 p. 

45819726 2021805 Dorgerloh, M. (1999) BSN 2060 SC 240--Acute Toxicity (96 Hours) to Bluegill (Lepomis 

macrochirus) in a Static Test: Lab Project Number: DOM 99088: E 252 1697-2: 00482. 

Unpublished study prepared by Bayer Ag Crop Protection. 44 p. 

72-2 Acute Toxicity to Freshwater Invertebrates 

MRID Citation Reference 

 

45819729 2021808 Heimbach, F. (1999) Acute Toxicity of BSN 2060 SC 240 to Waterfleas (Daphnia magna): 

Lab Project Number: E 320 1672-1: HBF/DM 213: MR-442/99. Unpublished study prepared 

by Bayer Ag Crop Protection. 29 p. 

45819730 2021809 Heimbach, F. (2000) Acute Toxicity of BSN 2060-Enol to Waterfleas (Daphnia magna): Lab 

Project Number: E 320 1716-0: HBF/DM 219: MR-602/99. Unpublished study prepared by 

Bayer Ag Crop Protection. 35 p. 

45854512 2021782 Kern, M.; Lam, C. (2000) Acute Toxicity of BSN 2060 Technical to the Waterflea (Daphnia 

magna) Under Static Conditions: Lab Project Number: BS820701: 109247. Unpublished 

study prepared by Bayer Corporation. 30 p. 

72-3 Acute Toxicity to Estuarine/Marine Organisms 

MRID Citation Reference 

45819702 2021784 Lima, W. (2001) BSN 2060--Acute Toxicity to Mysids (Americamysis bahia) Under FlowThrough Conditions: Lab Project Number: BS833101: 110404: 13507.6133. Unpublished 

study prepared by Springborn Laboratories, Inc. 48 p. {OPPTS 850.1035} 

45819708 2021790 Hancock, G.; Woodard, D. (2002) Acute Toxicity of BSN 2060 Technical to the Sheepshead 

Minnow (Cyprinodon variegatus) Under Flow-through Conditions: Lab Project Number: 

110974: BS812801. Unpublished study prepared by Bayer Corporation. 31 p. 

45819715 2021796 Dionne, E. (2002) BSN 2060--Acute Toxicity to Eastern Oysters (Crassostrea virginica) 

Under Flow-through Conditions: Lab Project Number: 13507.6132: BS861501: 200174. 

Unpublished study prepared by Springborn Laboratories, Inc. 56 p. {OPPTS 850.1025} 

72-4 Fish Early Life Stage/Aquatic Invertebrate Life Cycle Study 

MRID Citation Reference 

45819627 2021779 Sousa, J. (2001) BSN 2060 Enol (BSN 0546)--Early Life-Stage Toxicity Test with Rainbow 

Trout (Oncoryhnchus mykiss): Lab Project Number: 13507.6136: BS842201: 110284. 

Unpublished study prepared by Springborn Laboratories, Inc. 71 p. 

45819701 2021783 Kern, M.; Hall, A.; Mattern, G. (2002) Chronic Toxicity of BSN 2060 Enol to the Waterflea 

(Daphnia magna) Under Flow-Through Conditions: Lab Project Number: BS880701: 110349. 

Unpublished study prepared by Bayer Corporation. 60 p. 

45819705 2021787 Kern, M.; Hall, A.; Lam, C. (2002) Chronic Toxicity of BSN 2060 Technical to the Waterflea 

(Daphnia magna) Under Flow-Through Conditions: Lab Project Number: BS820702: 110612. 

Unpublished study prepared by Bayer Corporation. 60 p. 

45819710 2021792 Hall, A.; Kern, M.; Mattern, G. (2002) Chronic Toxicity of BSN 2060 240 SC to the Waterflea 

(Daphnia Magna) Under a Two Pulse Exposure Regime: Lab Project Number: 110992: 

BS820703. Unpublished study prepared by Bayer Corporation. 117 p. 
41 

45819711 2025446 Lima, W. (2002) BSN 2060--Life Cycle Toxicity Test with Mysids (Americamysis bahia): Lab 

Project Number: BS843101: 111024: 13507.6134. Unpublished study prepared by 

Springborn Laboratories, Inc. 71 p. 

45819727 2021806 Dorgerloh, M.; Sommer, H. (2001) BSN 2060--Early Life Stage Toxicity to Rainbow Trout 

(Oncorhynchus mykiss) Under Flow-Through Conditions: Lab Project Number: DOM 99124: 

E 284 1484-1: 00482. Unpublished study prepared by Bayer Ag Crop Protection. 90 p. 

45819713 2021794 Hall, A.; Hancock, G.; Leimkuehler, W. (2002) BSN 2060 240 SC Extended Laboratory Test 

to Assess Effects on a Population of Daphnia magna Under a Two Pulse Exposure Regime: 

Lab Project Number: BS880702: 200062. Unpublished study prepared by Bayer Corporation. 

104 p. 

72-5 Life cycle fish 

MRID Citation Reference 

45819712 2021793 Dionne, E. (2002) BSN 2060--The Full Life-Cycle Toxicity Test with Fathead Minnow 

(Pimephales promelas): Lab Project Number: 200052: BS851201: 13507.6138. Unpublished 

study prepared by Springborn Smithers Laboratories. 141 p. 

122-1 Seed Germination/Seedline Emergence and Vegetable Vigor 

MRID Citation Reference 

45819706 2021788 

2025445 

Bowers, L. (2002) Tier 1 Seedling Emergence and Vegetative Vigor Non-target Phytotoxicity 

Study Using BSN 2060 SC 240: Lab Project Number: 110851: BS451601: BS451602. 

Unpublished study prepared by Bayer Corporation. 111 p. 

123-1 Seed germination/seedling emergence and vegitative vigor 

MRID Citation Reference 

45819629 2021781 Bowers, L. (2002) Tier 2 Seedling Emergence and Vegetative Vigor Non-target Phytotoxicity 

Study Using BSN 2060 SC 240: Lab Project Number: BS451603: BS451605: BS451604. 

Unpublished study prepared by Bayer Corporation. 101 p. 

123-2 Aquatic plant growth 

MRID Citation Reference 

45819703 2021785 

2025443 

Hancock, G.; Lam, C. (2002) Toxicity of BSN 2060 Technical to the Green Alga 

Pseudokirchneriella subcaptitat formerly Selenastrum capricornutum: Lab Project Number: 

110407: BS823501. Unpublished study prepared by Bayer Corporation. 42 p. 

45819714 2021795 

2025444 

Kern, M.; Lam, C. (2002) Toxicity of BSN 2060 Technical to Duckweed (Lemna gibba G3): 

Lab Project Number: 200072: BS883701. Unpublished study prepared by Bayer Corporation. 

45 p. {OPPTS 850.4400} 

45819716 2021797 Seyfried, B. (2000) Toxicity of BSN 2060-Enol to Pseudokirchneriella subcapitata (formerly 

Selenastrum capricornutum) in a 96-Hour Algal Growth Inhibition Test: Lab Project Number: 

737414: 200188: 737425. Unpublished study prepared by RCC Ltd. 48 p. {OPPTS 

850.5400} 

141-1 Honey bee acute contact 
42 

MRID Citation Reference 

45819717 2021798 Wilhelmy, H. (2000) BSN 2060 SC 240 Acute Effects on the Honeybee Apis mellifera

(Hymenoptera, Apidae): Lab Project Number: 200195: IBA63641: 990222BN. Unpublished 

study prepared by Dr. U. Noack Laboratorium. 34 p. 

45819718 2021799 Wilhelmy, H. (2000) BSN 2060 a.i. Acute Effects on the Honeybee Apis mellifera

(Hymenoptera, Apidae): Lab Project Number: 200196: IBA64031: 980708BN. Unpublished 

study prepared by Dr. U. Noack Laboratorium. 36 p. 

141-4 Honey Bee Subacute Dietary Toxicity 

MRID Citation Reference 

45819718 2021799 Wilhelmy, H. (2000) BSN 2060 a.i. Acute Effects on the Honeybee Apis mellifera

(Hymenoptera, Apidae): Lab Project Number: 200196: IBA64031: 980708BN. Unpublished 

study prepared by Dr. U. Noack Laboratorium. 36 p. 

850.3030 Honey bee toxicity of residues on foliage 

MRID Citation Reference 

47737801 Flonicamid. Walsh, D. (2009) Pollinator Pesticide Safety Trials 2007: Flonicamid. Project Number: 

IB/2009/PH/002/01. Unpublished study prepared by Washington State University. 19 p. 

850.3040 Field testing for pollinators 

MRID Citation Reference 

47093201 2063654 

memo + DER 

Richards, K. (2007) Evaluation of inci 2SC when Applied to the Food Source of Honeybees 

(Apis mellifera L.). Project Number: CAR/155/05, EBBSX046. Unpublished study prepared 

by Bayer CropScience LP and California Agricultural Research Inc. 131 p. 

47344401 2079145- 

memo + DER 

as appendix 

Richards, K. (2008) Evaluation of OBERON 2SC When Applied to a Commercial Cotton 

Field Food Source on Honeybee (Apis mellifera L) Hives. Project Number: CAR/121/07, 

EBBSL001. Unpublished study prepared by California Agricultural Research Inc. and Bayer 

Cropscience. 114 p. 

47917201 2081101 = 

protocol 

review 

Rogers, R.; Williams, G.; Binns, M. (2009) Honey Bee Field Study in Melons Treated with 

Oberon 2SC: Final Report. Project Number: EBBSY008, EBBSY008/1. Unpublished study 

prepared by Wildwood Labs, Inc. 316 p. 

48033501 2085156 

2085152 - 

memo 

Bakker, F. (2010) A Greenhouse Study to Determine the Effects of Spiromesifen SC 240 on 

the Honeybee, under Particular Consideration of Effects to the Development of Honeybee 

Brood. Project Number: M/360890/02/1, B149AMS. Unpublished study prepared by MITOX 

Consultants. 98 p. 

142-1 Acute Toxicity to Aquatic Insects 

MRID Citation Reference 

45819728 2021807 Heimbach, F. (1999) Influence of BSN 2060 (tech.) on Development and Emergence of 
43 

Larvae of Chironomus riparius in a Water-Sediment System: Lab Project Number: 

HBF/CH32: E 416 1525-4. Unpublished study prepared by Bayer Ag Crop Protection. 47 p. 

47133103 2066627 Dorgerloh, M. (2007) Chironomus riparius 28-Day Chronic Toxicity Test with Spiromesifen 

(tech.) in a Water-Sediment System Using Spiked Sediment. Project Number: 

M/287709/01/1, E/416/3278/1, EBBSX045. Unpublished study prepared by Bayer Ag. 145 p. 

Non Guideline Selections 

45819731 2021810 Heimbach, F. (1999) Acute Toxicity of BSN 2060 (tech.) to Earthworms Eisenia fetida: Lab 

Project Number: HBF/RG 292: E 310 1536-9. Unpublished study prepared by Bayer Ag Crop 

Protection. 17 p. 

45819732 2021812 Heimbach, F. (1999) Influence of BSN 2060 SC 240 on the Reproduction of Earthworms 

Eisenia fetida: Lab Project Number: E 312 1653-1: HBF/RG 304. Unpublished study 

prepared by Bayer Ag Crop Protection. 23 p. 

45819733 2021811 Heimbach, F. (1999) Acute Toxicity of BSN 2060 SC 240 to Earthworms Eisenia fetida: Lab 

Project Number: HBF/RG311: E 310 1656-2. Unpublished study prepared by Bayer Ag Crop 

Protection. 17 p. 

46360501 Registrant 

response 

Bowers, L. (2004) Proposed Half-Life for Use in the Terrestrial Vertebrate Exposure 

Assessment for Spiromesifen. Project Number: 201159. Unpublished study prepared by 

Bayer Corp. 18 p. 

47133102 Fate study? Shepherd, J.; Allan, J. (2007) Fate of Spiromesifen-Dihydrofuranone-3-[14-Carbon] Applied 

to a Laboratory Sediment Followed by Flooding and Incubated for 28 Days. Project Number: 

MEBSX019. Unpublished study prepared by Bayer CropScience LP. 52 p. 
44 

APPENDIX B. Ecological Incident Information System and Aggregate Incident Database Report for Spiro

PC Code ommon Nam Type Incident ID Use Site Start Date Legality Certainty Country State County Year otal Magnitu Appl. RateAppl. Method Air/Gnd 

024875

Spiromesifen PLANTS

I016912-017 Broccoli 12-Oct-05 Undetermined Probable USA AZ Yuma 2005 166 acres

7.5 oz/acre Spray Air

024875

Spiromesifen PLANTS

I016912-021

Greenhouse 01-Jun-05 Registered use Possible USA CA San Diego 2005 unknown 4 lb/gal

024875

Spiromesifen PLANTS

I017073-005

Greenhouse 09-Jan-06 Registered use Possible USA FL 2006

50% of area treated 4 lb/gal NR Gnd 

024875

Spiromesifen PLANTS

I017245-008 Dracaena 09-Dec-05 Registered Use Possible USA MN Rice 2005

121,000 plants

024875

Spiromesifen PLANTS

I017358-032

Ornamental, herbaceous 13-Apr-06 Registered Use Possible USA PA 2006

3 fl oz/100 gal Spray Gnd

024875

Spiromesifen PLANTS

I017496-017

Greenhouse 12-Dec-05 Registered Use Possible USA HI Hawaii 2005

$20,000-30,000

3 fl oz/100 gal Spray Gnd

024875

Spiromesifen PLANTS

I018502-018

Greenhouse 18-Apr-07 Undetermined Possible USA FL 2007 200/gal A Spray Gnd

024875

Spiromesifen PLANTS

I018718-036

Ornamental, woody 01-Jun-07 Registered Use Probable USA VA Fauquier 2007 Unknown

4 lb/100 gal Spray Gnd 

024875

Spiromesifen

TERRESTRIAL

I020741-001 Corn 19-Jul-06 Undetermined Unlikely USA CO Larimer 2006

22 bee hives Air 
45 
46 

Appendix C. Results from the Screening Tool for Inhalation Risk Assessment (STIR) 

 

Welcome to the EFED 

Screening Tool for Inhalation Risk

This tool is designed to provide the risk assessor with a rapid method for determining the potential

significance of the inhalation exposure route to birds and mammals in a risk assessment.

Input

Application and Chemical Information

Enter Chemical Name Spiromesifen

Enter Chemical Use insecticide

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) 370.5

Enter Chemical Vapor Pressure (mmHg) 7.50E-08

Enter Application Rate (lb a.i./acre) 3

Toxicity Properties

Bird

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

Enter Mineau Scaling Factor 1.15

Enter Tested Bird Weight (kg) 0.178

Mammal

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

Enter Lowest Rat Inhalation LC50 (mg/L) 4.873

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) 1.50E-03

Maximum 1-hour Vapor Inhalation Dose (mg/kg) 1.88E-04

Adjusted Inhalation LD50 2.72E+01

Ratio of Vapor Dose to Adjusted Inhalation LD50 6.92E-06 Exposure not Likely Significant

Maximum Post-treatment Spray Inhalation Dose (mg/kg) 3.17E-01

Ratio of Droplet Inhalation Dose to Adjusted Inhalation LD50 1.17E-02 Exposure not Likely Significant

Results Mammalian (0.015 kg )

Maximum Vapor Concentration in Air at Saturation (mg/m3) 1.50E-03

Maximum 1-hour Vapor Inhalation Dose (mg/kg) 2.36E-04

Adjusted Inhalation LD50 2.90E+02

Ratio of Vapor Dose to Adjusted Inhalation LD50 8.14E-07 Exposure not Likely Significant

Maximum Post-treatment Spray Inhalation Dose (mg/kg) 3.98E-01

Ratio of Droplet Inhalation Dose to Adjusted Inhalation LD50 1.37E-03 Exposure not Likely Significant

**NOTE**: When entering values, press

order to update linked cells.