1

IR4 New Use for Spirotetramat on Taro Leaves, 

Watercress, Pomegranate, Banana, Bulb Vegetable, 

Low Growing Berry, Bushberry, Globe Artichoke, 

Fruiting Vegetable, Pome Fruit, Citrus Fruit, 

Pineapple, and Coffee

(PC 392201); D398764

Date: 12-13-12

Prepared by:

Joseph DeCant, Ecologist

José Meléndez, Chemist

U. S. Environmental Protection Agency

Office of Pesticide Programs

Environmental Fate and Effects Division

Environmental Risk Branch IV

1200 Pennsylvania Ave., NW

Mail Code 7507P

Washington, DC 20460

Approved by:

Mah Shamim, PhD, Branch Chief
2

Executive Summary

Spirotetramat (CAS No. 203313-25-5; CAS Name cis-3-(2,5-dimethylphenyl)-8-methoxy-2-oxo1-azaspiro[4.5]dec-3-en-4-yl ethyl carbonate; IUPAC Name cis-4-(ethoxycarbonyloxy)-8-

methoxy-3-(2,5-xylyl)-1-azaspiro[4.5]dec-3-en-2-one) is a systemic broad spectrum tetramic 

acid insecticide (ketoenole) that is to be applied as a preventative treatment during an early 

threshold of developing chewing insect populations including aphids, whiteflies and mealy bugs,

when sufficient leaf tissue is present for uptake and translocation to occur within agricultural 

crops. Spirotetramat’s mode of action is lipid biosynthesis inhibition (LBI), which is classified 

as a Group 23 Insecticide. According to the spirotetramat label it “is active primarily by 

ingestion against immature insect life stages.” 

The Environmental Fate and Effects Division (EFED) has completed its review of an IR-4 

petition for the use of Spirotetramat, MOVENTOTM (Reg. No. 264-1050), Ultor (Reg. No. 264-

1065), and BYI8330 (Reg. No. 264-1051), on taro leaves, watercress, pomegranate, banana, bulb 

vegetable, low growing berry, bushberry, globe artichoke, fruiting vegetable, pome fruit, citrus 

fruit, pineapple, and coffee. The Section 3 New Chemical assessment (D345278, 05/30/2008), is 

relevant to this assessment and provides background information on the chemical, its 

environmental fate and transport properties, ecotoxicity, and the overall problem formulation and 

conceptual model for spirotetramat. The recent Section 18 assessment (D403255, 07/26/2012), 

for the use on watercress, also provides information on the risk associated with the use of 

spirotetramat on watercress. This assessment builds on that foundation, and relies heavily on the 

previous risk assessments. An evaluation of the applications to the various proposed uses

suggests that this compound has potential to cause risk to the taxa identified in Table 1. 

Table 1. Summary of Environmental Risk Conclusions for Various Taxa Exposed to 

Spirotetramat for the Proposed Uses

Assessment Endpoint Identified Concerns Proposed Uses Associated with Risk a

Acute and Chronic Risk to 

Freshwater and 

Estuarine/marine Fish

Acute Watercress, Cranberry

Acute and Chronic Risk to 

Freshwater and 

Estuarine/Marine Invertebrates

Acute to all aquatic 

invertebrates and Chronic

to benthic invertebrates

Watercress, Cranberry

Aquatic Non-Vascular and 

Vascular Plants

Risk to Non-Vascular Watercress, Cranberry

Acute and Chronic Risk to 

Birds

Chronic Watercress, Banana/Plantain, Globe Artichoke, 

Citrus, Pome, Bushberry/Low Growing Berry, 

Coffee, Pineapple, Pomegranate, Bulb 

Vegetables

Acute and Chronic Risks to 

Mammals

Chronic Banana/ Plantain
3

Risks to Upland and Wetland 

Plants

None N/A

Concerns to Terrestrial NonTarget Insects

Acute and Chronic Citrus, Bushberry/Low Growing Berry, Pome, 

Coffee, Bulb Vegetable

Risks to Earthworms None N/A

a N/A = Not Applicable

Summary of Exposure and Associated Risk Conclusions

The environmental fate database is substantially complete. Additional fate data uncertainties are 

listed in Table 2.

Table 2. Environmental Fate Data Requirements for Spirotetramat

Guideline 

Number Data Requirement MRID#

Study 

Classification

Are Additional 

Data Needed for 

Risk Assessment?

Non-guideline Nature of NERs of Spirotetramat 47576501 Supplemental Yes1

1 The registrant should provide additional information characterizing the NERs. Unless proven otherwise, EFED 

will consider the NERs as repositories of toxic material.

In order to simplify this document, certain data has been appended as described in Table 3.

Table 3. Organization of the Appendices in this Risk Assessment

Appendix Title of Appendix Page

A Use information for spirotetramat new uses 2012 14

B Aquatic exposure assessment for the new uses of spirotetramat 2012 18

C Agency risk quotient (RQ) metrics and levels of concern (LOCs) per risk class 33

D Evaluation of the nature of non-extracted residues (NERs) in spirotetramat 

metabolism studies (MRID 47576501)

34

E Terrestrial exposure assessment for the new uses of spirotetramat 2012 38

The majority of the proposed use rates are equal to or less than previously registered uses. 

However, as Table A-1 in Appendix A shows, for bananas and watercress the proposed use 

rates are higher than previously registered uses. In addition, the use on cranberry and watercress 

represent aquatic use patterns. The increase in the use rates and the type of application for both 

watercress and cranberry resulted in higher aquatic EECs. 

Aquatic Risk Summary

A summary of the aquatic EEC’s along with the related risk quotients is presented in Tables 4

and 5 (for acute and chronic risk, respectively).

For the proposed terrestrial agricultural uses, the Florida citrus scenario, which was used as a 

surrogate for the proposed use on bananas and plantains, is the most conservative scenario with 

the highest aquatic EECs. This scenario as shown at the top of Tables 4 and 5 reveals that there 

are no exceedances of levels of concern (LOCs), for parent alone or for the total toxic residues, 
4

for any taxa related to acute and chronic exposure to aquatic animals or to exposure to aquatic 

vascular and non-vascular plants. Consequently, EFED concludes that the terrestrial agricultural 

uses do not pose any risk concern to aquatic taxa.

However, the aquatic agricultural uses on watercress and cranberry present risk concerns. 

Utilizing a Tier 1 aquatic tool (i.e., the Modified Tier 1 Rice Model, see the Appendix B), EEC’s 

for the watercress and cranberry uses reveal that parent spirotetramat, when considered alone, 

does not pose a concern for the most part, either acute or chronic, to any aquatic taxa. The one 

exception is a slight exceedance of the LOC for acute endangered species for the proposed use 

on watercress (RQ = 0.058 for freshwater invertebrates, compared to an LOC of 0.05). The 

primary issue, rather, is the role of the degradates and the non-extracted (or un-extracted) 

residues (NERs). The consideration of the NERs is explained in detail in Appendix D. 

As Table 4 shows, when the total toxic residues (TTR) and NERs are included in the expression 

of the EECs, the proposed use on watercress exceeds the acute risk LOC for freshwater 

invertebrates. Chronic risk to benthic invertebrates is also a concern (Table 5). Furthermore, the 

EEC’s exceed the acute endangered species and the acute restricted use LOCs for freshwater and 

saltwater invertebrates and fish, while also exceeding the aquatic non-vascular plant LOC.

Similarly, the proposed use on cranberry poses risk concerns to aquatic taxa. When the TTRs 

and NERs are included regardless of the timing of application, the RQs exceed the acute 

restricted use and acute endangered species LOCs for freshwater invertebrates and fish as well as 

saltwater invertebrates. In this scenario, the acute endangered species LOC is also exceeded for 

saltwater fish as well as chronic risk being present for benthic invertebrates. Even when the 

NERs are excluded, there is still acute restricted use and acute endangered species exceedances 

of the LOCs to those taxa highlighted in Table 4, as well as chronic concern for benthic 

invertebrates, when applications are made one day pre-flood. The concerns are entirely 

mitigated when the NERs are excluded and applications must be made no closer to the flood 

period than 30 days, but note that NERs are not taken into account and may underestimate the 

risk associated with this use of spirotetramat.

Table 4. Upper bound exposure and acute risk to aquatic animals and risk to aquatic plants.

Acute Aquatic Animals a Aquatic Plants b

Crop 

Scenario/App. 

rate/No. 

Apps/Int. 

Between 

Apps.

EEC/ppb Freshwater 

Invertebrates

Freshwater 

Fish

Estuarine/ 

Marine

Invertebrates

Estuarine/ 

Marine 

Fish

Vascularc

NonVascular

(nonlisted/ 

listed) 

Terrestrial Uses

FL citrus

0.25/ 5/ 14 1.46 0.0022 0.0010 0.0017 0.00075 0.00095 0.0041/ 0.012

FL citrus 

TTR + NERs

0.25/ 5/ 14

19.6 0.030 0.014 0.023 0.01 0.013 0.054/ 

0.16

Aquatic Uses

Watercress
5

Table 4. Upper bound exposure and acute risk to aquatic animals and risk to aquatic plants.

Acute Aquatic Animals a Aquatic Plants b

Crop 

Scenario/App. 

rate/No. 

Apps/Int. 

Between 

Apps.

EEC/ppb Freshwater 

Invertebrates

Freshwater 

Fish

Estuarine/ 

Marine

Invertebrates

Estuarine/ 

Marine 

Fish

Vascularc

NonVascular

(nonlisted/ 

listed) 

Spirotetramat 

only

0.2/ 2/ 7

38.6 0.058 0.027 0.045 0.020 0.025 0.11/ 

0.31

TTR + NERs

0.2/ 2/ 7 393 0.60 0.28 0.46 0.20 0.26 1.1/ 3.2

TTR 

(excluding the 

NERs)

0.2/ 2/ 7

373 0.57 0.26 0.44 0.19 0.24 1.0/ 3.0

Cranberry

Spirotetramat 

only

0.16/ 3/ 7 – 1 d 

pre-flood

5.50 0.0083 0.0039 0.0065 0.0028 0.0036 0.02/ 

0.044

TTR + NERs

0.16/ 3/ 7

1 d pre-flood

162 0.25 0.11 0.19 0.083 0.11 0.45/ 1.3

TTR + NERs

0.16/ 3/ 7

30 d pre-flood

141 0.21 0.1 0.17 0.072 0.10 0.39/ 1.1

TTR 

(excluding the 

NERs)

0.16/ 3/ 7

1 d pre-flood

114 0.17 0.081 0.13 0.058 0.074 0.32/ 

0.92

TTR 

(excluding the 

NERs)

0.16/ 3/ 7

30 d pre-flood

22.4 0.034 0.016 0.026 0.011 0.015 0.062/ 

0.18

a Toxicity values are based on studies with midges (Chironomus riparius) for freshwater invertebrates (EC50 = 660 μg a.i./L), bluegill sunfish 

(Lepomis macrochirus) for freshwater fish (LC50 = 1410 μg a.i./L), eastern oysters (Crassostrea virginica) for estuarine/marine invertebrates 

(EC50 = 850 μg a.i./L), and sheepshead minnow (Cyprinodon variegatus) for estuarine/marine fish (LC50 = 1960 μg a.i./L).

b Toxicity values are based on studies with duckweed (Lemna gibba) for vascular plants (EC50 = 4620 μg a.i./L; NOAEC=1540 μg a.i./L) and 

marine diatoms (Skeletonema costatum) for non-vascular plants (EC50 = 360 μg a.i./L; NOAEC=124 μg a.i./L).

c RQ’s are based on plant toxicity NOAEC’s. There are would also be no exceedances if the RQ’s were based on the EC50 because the NOAEC is 

a more sensitive endpoint than the EC50.

Table 5. Upper bound chronic exposure and risk quotients for aquatic invertebrates and fish. a

Crop Scenario/App. rate/No. 

Apps/Int. Between Apps.

Chronic

/ppb

(21d/60d) b

Freshwater Freeswimming InvertebratesBenthic 

Invertebrates

Freshwater 

Fish

Terrestrial Uses

FL citrus

0.25/ 5/ 14

0.0622/ 

0.0462 0.000031 0.00062 0.00012

FL citrus TTR

0.25/ 5/ 14 18.7/ 17.5 0.0094 0.19 0.035
6

Table 5. Upper bound chronic exposure and risk quotients for aquatic invertebrates and fish. a

Crop Scenario/App. rate/No. 

Apps/Int. Between Apps.

Chronic

/ppb

(21d/60d) b

Freshwater Freeswimming InvertebratesBenthic 

Invertebrates

Freshwater 

Fish

Aquatic Uses

Watercress

Spirotetramat only

0.2/ 2/ 7 1.99/ 0.695 0.0010 0.020 0.0037

TTR + NERs

0.2/ 2/ 7 381/ 359 0.19 3.81 0.71

TTR (excluding the NERs)

0.2/ 2/ 7 361/ 338 0.18 3.61 0.68

Cranberry

Spirotetramat only

0.16/ 3/ 7 – 1 d pre-flood

0.283/ 

0.0991 0.00014 0.0028 0.00053

TTR + NERs

0.16/ 3/ 7 – 1 d pre-flood 157/ 148 0.079 1.57 0.29

TTR + NERs

0.16/ 3/ 7 – 30 d pre-flood 137/ 129 0.069 1.37 0.26

TTR (excluding the NERs)

0.16/ 3/ 7 – 1 d pre-flood 110/ 103 0.055 1.1 0.21

TTR (excluding the NERs)

0.16/ 3/ 7 – 30 d pre-flood 21.6/ 20.3 0.012 0.22 0.040

a Chronic toxicity values are based on studies with water fleas (Daphnia magna) for freshwater invertebrates (NOAEC = 2000 μg a.i./L) and 

fathead minnows (Pimephales promelas) for freshwater fish (NOAEC = 534 μg a.i./L). For benthic invertebrates, the chronic toxicity value is 

based on Chironomus riparius (NOAEC = 100 μg a.i./L).

b Chronic 21 day and 60 day average exposure concentrations are shown. The 21 day average relates to aquatic invertebrates whereas the 60 day 

exposure concentrations relate to fish.

As is evident from the above tables, the NERs make a substantial contribution to the overall risk 

picture for aquatic plants and animals, but only in the case of the aquatic uses. When 

spirotetramat is modeled alone, it does not pose a concern to aquatic taxa, with the exception of 

the use on watercress, where there is a slight exceedance of the acute endangered species LOC 

for freshwater invertebrates (RQ = 0.06). The registrant has not provided information related to 

the inherent toxicity or identification of the possible compounds present in these NERs. The 

only rationale that the registrant has provided relates to the environmental fate of these residues 

as outlined in Appendix D. EFED maintains that these residues are environmentally relevant, 

which underscores the uncertainty related to the toxicity of these residues. It is possible that the 

RQs above may overestimate the risk due to the potential that the toxicity of spirotetramat is due 

to the parent and the main degradates that are considered toxic. Yet there is no information to 

refute the assumption that the NERs are also toxic. Note that for the cranberry use, if 

applications are made 30 days prior to flooding and if data show that the NERs are of no concern 

toxicologically, then RQs are below LOCs. Thus, the application timing can remove all risk 

concerns to aquatic organisms for the cranberry use (i.e., imposing a 30-day pre-flood 

restriction). For the watercress use, there would be risk whether the NERs are considered toxic 

or not and restrictions such as the ones for cranberry could not be imposed. Watercress 

cultivation requires that the crop be flooded all throughout the growing period.

Besides the fact that the model functions as a Tier 1 tool, certain uncertainties surround the use 

of the Modified Tier I Rice Model for cranberry and watercress use. They have been described 

in previous Section 18 reviews (DP Barcodes D399023, dated 04/20/2012, and D403255, dated 
7

07/26/2012), and in the Appendix B. It is noted that the endpoints of the freshwater invertebrate

organisms using the midge, Chironomus riparius, were compared against the water column peak 

and 21-day EECs in the absence of pore water EECs. Using the Modified Tier 1 Rice Model, 

benthic sediment or pore water EECs cannot be estimated and a Tier 2 tool would be needed, 

such as the Pesticide Flooded Application Model (PFAM), which is currently being tested for 

quality assurance in EFED.

Terrestrial Risk Summary

A summary of terrestrial risk is found in Tables 6 through 9. Since the application rates and 

intervals between applications are similar to previous uses, risk conclusions from the previous S3 

New Chemical assessment (D345278) can be used in place of a new assessment for the majority 

of proposed uses. EFED selected two of the proposed uses that represent the highest application 

rates that have not been assessed in previous reviews. These higher use rates are for watercress 

and banana/plantain. For each crop application scenario based on maximum application rates, 

minimum application intervals, and the maximum number of applications, the use of 

spirotetramat, as parent alone or as total toxic residues, does not pose a concern to either birds or 

mammals on an acute exposure basis. Chronic exposure presents a concern, however. As Table 

8 shows, the EECs exceed the chronic LOC for birds under both crop scenarios whether parent 

alone or total toxic residues are considered. However, the chronic risk for mammals only 

appears when considering small mammals that use short grass as a food source and considers the 

total toxic residues. It is important to note that the actual chronic exposure levels as shown by 

Figures E-1 to E-4 in Appendix E reveal that peak exposure crosses the toxic effects threshold 

multiple times for both birds and mammals, which increases the likelihood of chronic effects that 

are reflected in the LOC exceedances. Furthermore, the chronic no-effect endpoint for birds is 

uncertain as toxic effects were found at the lowest treatment level, which suggests that the 

chronic RQs for birds may actually be greater than what was calculated.

Table 6. Upper bound acute dose-based Risk Quotients using T-REX v1.5 for the maximum spirotetramat 

spray application scenarios of various crops for birds. 

Use

RQ’s

Size 

class a

Short 

Grass

Long 

Grass

Broadleaf 

Plants

Arthropods Fruits, 

Pods Seeds

Parent only b

Watercress Small 0.05 0.02 0.03 0.02 0.00 0.00

Banana/ 

Plantains Small 0.05 0.02 0.03 0.02 0.00 0.00

Total Residues b

Watercress Small 0.05 0.02 0.03 0.02 0.00 0.00

Banana/ 

Plantains Small 0.06 0.03 0.03 0.02 0.00 0.00
8

Table 6. Upper bound acute dose-based Risk Quotients using T-REX v1.5 for the maximum spirotetramat 

spray application scenarios of various crops for birds. 

Use

RQ’s

Size 

class a

Short 

Grass

Long 

Grass

Broadleaf 

Plants

Arthropods Fruits, 

Pods Seeds

a There are three size classes of birds including small (20g), medium (100g), and large (1000g). Small birds represent the most sensitive size 

class and therefore the lack of risk concern to small birds from upper-bound exposure concentrations implies that there will also not be risk to 

other sizes of birds. 

b

For foliar dissipation, 16 foliar half-life measurements are available from two guideline studies (MRID 46904508 and MRID 46904509) and 

one non-guideline study (MRID 46904507) for both the parent spirotetramat as well as for the total residues (parent spirotetramat, spirotetramatenol, and spirotetramat-ketohydroxy). Assuming these values are distributed normally, the values which represent the one tail upper 90% 

confidence limit of the mean half-lives for the parent and total residue approaches are 3.3 and 5.3 days, respectively.

Table 7. Upper bound acute and chronic dosed-based Risk Quotients using T-REX v1.5 for the maximum 

spirotetramat spray application scenarios of various crops for mammals. 

Use

RQ’s (acute/chronic)

Size 

classa

Short 

Grass

Long 

Grass

Broadleaf 

Plants Arthropods Fruits, Pods Seeds

Parent only b

Watercress Small 0.01/0.03 0.01/0.01 0.01/0.01 0.01/0.01 0.00/0.00 0.00/0.00

Banana/ 

Plantains Small 0.01/0.03 0.01/0.01 0.01/0.02 0.01/0.01 0.00/0.00 0.00/0.00

Total Residues b

Watercress Small 0.01/0.03 0.01/0.01 0.01/0.02 0.01/0.01 0.00/0.00 0.00/0.00

Banana/ 

Plantains Small 0.02/0.03 0.01/0.01 0.01/0.02 0.01/0.01 0.00/0.00 0.00/0.00

a There are three size classes of mammals including small (15g), medium (35g), and large (1000g). Small mammals represent the most sensitive 

size class and therefore the lack of risk concern to small mammals from upper-bound exposure concentrations implies that there will also not be 

risk to other sizes of birds. 

b

For foliar dissipation, 16 foliar half-life measurements are available from two guideline studies (MRID 46904508 and MRID 46904509) and 

one non-guideline study (MRID 46904507) for both the parent spirotetramat as well as for the total residues (parent spirotetramat, spirotetramatenol, and spirotetramat-ketohydroxy). Assuming these values are distributed normally, the values which represent the one tail upper 90% 

confidence limit of the mean half-lives for the parent and total residue approaches are 3.3 and 5.3 days, respectively.

Table 8. Upper bound chronic dietary-based Risk Quotients using T-REX v1.5 for the maximum 

spirotetramat spray application scenarios of various crops for birds and mammals. 

Use Taxa

Dietary Based RQ’s

Short 

Grass

Long 

Grass

Broadleaf 

Plants

Arthropods Fruits, Pods, 

Seeds

Parent only a

Watercress

Bird 2.05 0.94 1.15 0.80 0.13

Mammal 0.83 0.38 0.47 0.05 0.33

Banana/ Plantains

Bird 2.20 1.01 1.24 0.86 0.14

Mammal 0.90 0.41 0.50 0.35 0.06
9

Table 8. Upper bound chronic dietary-based Risk Quotients using T-REX v1.5 for the maximum 

spirotetramat spray application scenarios of various crops for birds and mammals. 

Use Taxa

Dietary Based RQ’s

Short 

Grass

Long 

Grass

Broadleaf 

Plants

Arthropods Fruits, Pods, 

Seeds

Total Residues a

Watercress

Bird 2.33 1.07 1.31 0.91 0.15

Mammal 0.95 0.44 0.53 0.37 0.06

Banana/ Plantains

Bird 2.48 1.14 1.40 0.16 0.97

Mammal 1.01 0.46 0.57 0.40 0.06

a

For foliar dissipation, 16 foliar half-life measurements are available from two guideline studies (MRID 46904508 and MRID 46904509) and 

one non-guideline study (MRID 46904507) for both the parent spirotetramat as well as for the total residues (parent spirotetramat, 

spirotetramat-enol, and spirotetramat-ketohydroxy). Assuming these values are distributed normally, the values which represent the one tail 

upper 90% confidence limit of the mean half-lives for the parent and total residue approaches are 3.3 and 5.3 days, respectively.

It is important to note that these terrestrial risk concerns represent upper bound exposure 

scenarios. Related to the risk concerns identified in Table 8, these concerns for all taxa and all 

scenarios are removed when using the mean exposure values. Consequently, this difference 

highlights the concern that under some circumstances, the use of spirotetramat will pose no 

concern either on an acute or chronic basis to mammals and birds. Under worst case conditions 

that result in high levels of food contamination, however, both federally listed and non-listed 

birds would be at risk from chronic exposure when they repeatedly consume food items that are 

contaminated by these two application scenarios. Federally listed and non-listed mammals that 

consume primarily short grass food sources would be at risk as well from the proposed uses on 

banana and plantain due to chronic exposure. Based on the risk conclusions in the S3 New 

Chemical assessment for uses with similar application rates, the proposed uses of globe 

artichoke, citrus, pome, bushberry/low growing berry, coffee, pineapple, pomegranate, and bulb 

vegetables also present a chronic risk to birds.

The proposed uses of spirotetramat do not present a risk of concern to terrestrial plants. Table 9

illustrates the RQ’s that result from the banana/plantain application scenario, which is the highest 

application rate of any use for spirotetramat. This application scencario therefore serves as a 

conservative scenario. In light of the lack of any exceedances of the plant LOCs in this scenario, 

none of the proposed uses present a risk of concern to terrestrial plants from either run-off or 

spray drift alone.

Table 9. RQs for non-target plants inhabiting dry (upland) and semi-aquatic (wetland) areas based on EECs 

of total spirotetramat (parent + degradates) residues on plants following the maximum exposure scenario of 

all crops (Banana/Plantain Scenario) using the TerrPlant model (lbs a.i./A) for run-off and spray drift alone.a

Application 

Method;

Rate

Plant 

Type

Upland Wetland Drift Only

EEC

lb ai/A

NonListed 

RQb

Listed 

RQc

EEC

lb ai/A

NonListed 

RQb

Listed 

RQc

EEC

lb ai/A

NonListed 

RQ

Listed 

RQ

Aerial Spray 

Application, 

Unincorp.; 

0.25 lb 

Monocot 0.005 0.11 0.11 0.05 0.39 0.39 0.0625 0.21 <0.1
10

Table 9. RQs for non-target plants inhabiting dry (upland) and semi-aquatic (wetland) areas based on EECs 

of total spirotetramat (parent + degradates) residues on plants following the maximum exposure scenario of 

all crops (Banana/Plantain Scenario) using the TerrPlant model (lbs a.i./A) for run-off and spray drift alone.a

Application 

Method;

Rate

Plant 

Type

Upland Wetland Drift Only

EEC

lb ai/A

NonListed 

RQb

Listed 

RQc

EEC

lb ai/A

NonListed 

RQb

Listed 

RQc

EEC

lb ai/A

NonListed 

RQ

Listed 

RQ

a.i./A

Dicot 0.11 0.11 0.39 0.39 <0.1 <0.1

a EECs and RQs are based on the most conservative modeling scenario possible for spirotetramat. Specifically, it was assumed that spirotetramat 

was not ground incorporated, it was applied at the maximum single application rate for all uses (0.25 lb a.i/A) with aerial application methods 

(drift fraction = 0.05), and that the solubility is between 10 and 100 mg/L (solubility fraction=0.02). 

b

 The most sensitive EC25 value from seedling emergence studies used to derive RQs for non-listed plants in upland and wetland areas was >0.16 

lb a.i./A for both monocots and dicots.

c

 The most sensitive NOAEC value from seedling emergence studies used to derive RQs for listed plants in upland and wetland areas was 0.16 lb 

a.i./A for both monocots and dicots.

d

 The most sensitive EC25 values from vegetative vigor studies used to derive RQs for non-listed plants exposed to drift only were 0.06 and >0.16 

lb a.i./A for monocots and dicots, respectively.

e

The most sensitive NOAEC values from vegetative vigor studies used to derive RQs for listed plants exposed to drift only were 0.02 and >0.16 

lb a.i./A for monocots and dicots, respectively.

Currently, the Agency does not quantitatively evaluate the risk to terrestrial invertebrates from

pesticides for screening level assessments for non-endangered species. However, risks to nontarget listed insects cannot be precluded. Although the intrinsic hazard potential to bees based on 

the acute oral and contact studies with adult honey bees appears to be low, brood feeding tests 

with bees and acute toxicity contact studies with other non-target insects (e.g. parasitoid wasps 

and predatory mites) suggest that there is potential for mortality primarily in pupae, perturbation 

of brood development, and early brood termination as a result of spirotetramat use. In addition, 

data on two other chemicals representing the ketoenole class of compounds (spiromesifen and 

spirodiclofen) also demonstrate that compounds with this mode of action (i.e., inhibition of lipid 

biosynthesis) may adversely affect bee broods and development while displaying low acute 

toxicity to adult honey bees. 

Higher tier studies to date for spirotetramat have been found to be insufficient to address the 

hazard of spirotetramat to bee brood and hive survival. The previous S3 New Use (D384525, 

dated 12/7/2010) provides a review of many of the higher tier studies submitted for 

spirotetramat. Two new Tier III full field studies have been submitted to the Agency since the 

last S3 New Use, and EFED has reviewed these studies as well. The first tier III field study, 

MRID 48159802, evaluated the impact of spirotetramat to honey bee colonies under full field 

conditions after two applications of 96 g a.i./ha/m canopy height (0.086 lb a.i./acre/m canopy 

height), which resulted in total applications of 278.4, 240.0, 230.4, and 172.8 g a.i./ha (0.25, 

0.21, 0.21, and 0.15 lb a.i./acre). Note that the maximum seasonal application rate in the U.S. is 

0.31 lb a.i./acre. This study is also classified as supplemental because it provides useful 

information on the residue levels. However, the study also has deficiencies related to the 

evaluation of the toxicity of the test compound. Due to the lack of confirmation of hive exposure 

to spirotetramat residues, the likely alternative sources of forage, and the unequal fluctuations in 

the blossom abundance between and within treatment and control citrus groves over time 
11

preclude the ability to adequately evaluate the toxicity of spirotetramat residues on hive brood 

and hive stability.

Another study, MRID 48159801, is classified as supplemental. The study was conducted with 

one application of spirotetramat at 0.16 lbs ai/A to citrus at bloom and followed the condition of 

both treated and control hives as they progressed through a season of commercial pollination. 

Note that this rate is equivalent to the maximum single application rate, but is half of the 

maximum seasonal application rate that may be applied to citrus in the U.S. Due to the many 

stresses placed on both the control and treated groups over the course of the commercial 

pollination, the study did not provide a useful evaluation of the toxicity of spirotetramat to honey 

bee colonies. However, the study provided useful information on the residue levels that would 

be encountered with an application to citrus at bloom. Yet there are uncertainties in the levels of 

residues as well. The study measured the parent and the enol metabolites, but it did not measure 

the keto-hydroxy metabolite, which is also of concern to honeybees. Furthermore, EFED 

reviewed a protocol (D397343, 397373) for a field residue study for citrus that included a 

justification from Bayer CropScience (BCS) as to why they intended to only evaluate the parent 

and the enol-metabolite. From the data that they submitted, EFED was able to conclude that 

there remains insufficient justification for ruling out the keto-hydroxy metabolite as a metabolite 

of concern. EFED also concluded that the enol-glucoside metabolite should be measured in 

future residue studies. 

This previous review of spirotetramat residues (D397343+) also highlighted another uncertainty 

surrounding the residue data. The uncertainty relates to the enol-glucoside metabolite, which 

forms when plants metabolize the enol metabolite into the enol-glucoside metabolite. The latter 

can then be metabolized back into the enol metabolite through biologically mediated processes in 

the digestive system of the rat. It is possible that enzymatic processes in the honey bee hive may 

also effect the same transformation of the enol-glucoside into the enol metabolite, the latter of 

which is of toxicological concern to the honey bee hive. Data presented in a field study on citrus 

(MRID48159802) that measured residues of the enol-glucoside in citrus blossoms showed that 

these residues continued to increase at the final sampling date of 15 days following the last 

application. These data suggest that while the parent compound and primary metabolites of 

concern (enol and keto-hydroxy) decrease in concentration after 7 days, the enol-glucoside 

actually increases in concentration after 7 days with the potential to be transformed back into the 

enol metabolite through biologically mediated processes.

Based on the physical properties of spirotetramat and its systemic nature as well as the higher tier 

studies, EFED identifies that the period of concern for spirotetramat applications is the period 

before bloom, during bloom, and until petal fall is complete. In most cases for the proposed 

uses, the crops are not attractive to pollinators, are harvested before flowering, or are of 

relatively low acreage to be of concern to bees within the landscape. Uncertainties in exposure 

to invertebrate pollinators related to the proposed uses remain primarily for the proposed tree 

crops and bushberry/low growing berry use due to the potential for carry-over of residues from 

one season to the next. Therefore, non-guideline residue data are needed that addresses the 

systemic residues in these crop groups while a field study on the toxicity of spirotetramat 

(850.3040) is being placed in reserve pending the outcome of the residue studies. If the residue 
12

studies show that bees will continue to be exposed to spirotetramat residues despite any potential

protective label language, then additional data may be needed. 

In addition, though bulb vegetables are of low attractiveness to pollinators, many bulb vegetables 

are commercially pollinated for seed production. These crops are sources of nectar for these 

commercially managed hives, which the bees will bring back to the hive to serve as a food 

source for the colony. An appropriate pre-bloom application window may potentially support a 

reduction of risk concern for the colonies. Several studies submitted by Bayer CropScience 

support this conclusion. Study MRID 47563310 shows that total residues in nectar for Phacelia 

tanacetifolia begin to decline at 7 days after application, though total residues (parent + enol + 

keto-hydroxy) persist at least 10 days in nectar with a mean value of 0.22 mg/kg. A study with 

summer oilseed rape (MRID 47563311) also shows that spirotetramat total residues (parent + 

enol + keto-hydroxy) begin to decline at 7 days in nectar (mean = 0.04 mg/kg), though the 

decline is slow. In contrast, a study on residues in citrus nectar (MRID47563312) show that the 

total residues were below the LOQ at 7 days following the last application, though this may be a 

function of a relatively high LOQ of 0.0545 mg a.i./kg. Similarly, when evaluating nectar 

residues in melon (47563308), residue levels were below the LOQ of 0.0545 mg/kg at even 5 

days after treatment when spirotetramat was applied at flowering. A field study with 

spirotetramat on citrus (MRID 48159801) revealed that total residues (parent + enol) in nectar 

remain fairly constant up to 7 days after application when made at bloom with mean 

concentrations of 0.01 mg/kg. Another field study with spirotetramat on citrus (MRID 

47563304) revealed that concentrations were less than 0.01 mg/kg total residues (parent + enol) 

at 7 days and beyond the last application. Given all of this data, it appears that total residues 

(parent + enol + keto-hydroxy) of spirotetramat in nectar remain relatively low compared to 

pollen and decline after 7 days following application, but the decline occurs slowly and with 

some plants retaining mean total residue levels as high as 0.22 mg/kg. However, uncertainty 

remains related to the relationship for the time between application and flowering and the residue 

levels in the nectar.

For the proposed use, there is therefore uncertainty related to the bulb vegetables grown

specifically for seed production with pre-bloom applications of spirotetramat. With that in mind, 

the currently available data do not provide enough information on pre-bloom applications to 

address the efficacy of pre-bloom use patterns or restrictions to eliminate exposure to 

invertebrate pollinators. There is also insufficient toxicity data to establish a toxic threshold. In 

order to address concerns related to the commercially managed hives that are used to pollinate 

these specific crops, data needs would include residue levels in these bulb vegetables in the 

flower nectar with the expected application dates of spirotetramat at the maximum application 

rate and the minimum application interval. Information on the potential transformation of the 

enol-glucoside by honey bees would be highly beneficial as well. Finally, toxicity data to bee 

brood at the levels expected in these bulb vegetables. However, it is also important to note that 

these bulb vegetables grown for seed production would comprise a relatively low total acreage. 

Even with protective label language that may limit applications to after petal fall, other concerns 

remain for spray drift of spirotetramat to blooming plants adjacent to the site of application that 

may be contaminated, regardless of the crop. These blooming plants may serve as a food source 

to bees. The absence of data on effects to invertebrate pollinators from spray drift to adjacent 
13

blooming plants is an uncertainty, and so efforts should be made to minimize drift to adjacent 

areas with blooming flowers.

For citrus, EFED suggests that the original label statement, “Do not apply this product within 10 

days prior to bloom, during bloom, or until petal fall is complete”, may be used. Data should be 

submitted to EPA to confirm and quantify levels of residues in citrus leaves, pollen, and nectar 

after applications at different times before bloom. The purpose of the study is to evaluate residue 

levels at 10 days before bloom and prior to 10 days before bloom in order to better evaluate 

exposure to bees, and, if necessary, to revise the appropriate pre-bloom “window” necessary to 

protect pollinators. EFED has previously commented on a protocol for evaluating residues in 

citrus (D397343, 397373), but this data has not yet been submitted to the Agency. 
14

Appendix A. Use Information for Spirotetramat New Uses 2012

Table A-1 is a summary of all agricultural use patterns for spirotetramat in the labels for BYI 

8330 150 OD Insecticide (oil dispersion, Reg. No. 264-1051), MOVENTO®SC (suspension 

concentrate, Reg. No. 264-1050), and the ULTOR® (suspension concentrate, Reg. No. 264-

1075).

Table A-1. Summary use information for spirotetramat based on labels for BYI 8330 150 OD 

Insecticide), MOVENTO®and ULTOR®. The new uses are shaded yellow.

USE

SINGLE 

APP. RATE 

(lb. a.i./A)

NUMBER 

OF APPS.

SEASONAL 

APP. RATE 

(lb. a.i./A)

INTERVAL 

BETWEEN 

APPS. (days)

APP.

METHOD

PHI 

(days)

Soybean 0.08 2 0.16 7 G*, A 21

Tropical Fruits (acerola, avocado, 

black sapote, canistel, feijoa, guava, 

longan, lychee, mamey sapote, 

mango, papaya, passionfruit, 

persimmon, pulasan, rambutan, 

sapodilla, Spanish lime, star apple, 

starfruit, wax jambo, white sapote, 

jaboticaba)

0.16 3 0.40 14 G*, A, 

Airblast

1

Legume Vegetables (Crop 

Group 6, except dry soybean) 

(Edible Podded and Succulent 

Shelled Pea and Bean and Dried 

Shelled Pea and Bean

Bean (Lupinus spp., including grain 

lupin, sweet lupin, white lupin, and 

white sweet lupin)

Bean (Phaseolus spp., including 

field bean, kidney bean, lima bean, 

navy bean, pinto bean, runner bean, 

snap bean, tepary bean, wax bean)

Bean (Vigna spp., including adzuki 

bean, asparagus bean, blackeyed 

pea, catjang, Chinese longbean, 

cowpea, Crowder pea, moth bean, 

mung bean, rice bean, Southern pea, 

urd bean, yardlong bean)

Pea (Pisum spp. including dwarf 

pea, edible-pod pea, English pea, 

field pea, garden pea, green pea, 

snow pea, sugar snap pea)

Other Beans and Peas (Broad bean 

(fava), Chickpea (garbanzo bean), 

Guar, Jackbean, Lablab bean 

(hyacinth bean), Lentil, Pigeon pea, 

soybean (immature seed), Sword 

bean) 

0.08 2 0.16 7 G*, A, C 1 edible 

podded, 

succulent 

beans and 

peas;

7 dry 

shelled 

beans and 

peas

Globe artichoke 0.12 ~5 0.5 7 G, A, C 3
15

Table A-1. Summary use information for spirotetramat based on labels for BYI 8330 150 OD 

Insecticide), MOVENTO®and ULTOR®. The new uses are shaded yellow.

USE

SINGLE 

APP. RATE 

(lb. a.i./A)

NUMBER 

OF APPS.

SEASONAL 

APP. RATE 

(lb. a.i./A)

INTERVAL 

BETWEEN 

APPS. (days)

APP.

METHOD

PHI 

(days)

Citrus Fruit (Crop Group 10-10, 

including, calamondin, citrus citron, 

citrus hybrids like chironja, tangelo 

and tangor, grapefruit, kumquat, 

lemon, lime, mandarin or tangelo, 

sweet and sour orange, pummelo, 

Satsuma mandarin, Australian lime 

(desert, finger, and round), Brown 

River finger lime, Japanese summer 

grapefruit, Mediterranean mandarin, 

Mount White lime, New Guinea 

wild lime, Russell River lime, sweet 

lime, Tachibana orange, Tahiti lime, 

Trifoliate orange, uniq fruit, 

including cultivars, varieties and/or 

hybrids of these commodities)

0.16 2 0.32 21 G*, A, 

Airblast

1

Grape and Small Fruit Vine 

Climbing Crop Subgroup 13-

07F (except Fuzzy kiwifruit/ 

includes grape, gooseberry, maypop, 

Schisandra berry, hardy kiwifruit)

0.13 2 0.2 30 G*, A, 

Airblast

7

Pome Fruit (Crop Group 11-10, 

including apple, crabapple, loquat, 

mayhaw, pear, Asian pear, quince, 

azarole, Chinese quince, Japanese 

quince, medlar, tejocote, hybrids, 

cultivars and/or varieties of these)

0.14 3 0.4 14 G*, A, 

Airblast

7

Stone Fruit (Crop Group 12, 

including apricot, sweet and tart 

cherry, nectarine, peach, plumvarious kinds, plumcot, and fresh 

and dried prune)

0.14 2 0.24 14 G*, A, 

Airblast

7

Tree Nuts (Crop Group 14 plus

pistachio, including almond, 

beechnut, Brazil nut, butternut, 

cashew, chestnut, chinquapin, filbert 

or hazelnut, hickory nut, macadamia 

nut or bush nut, pecan, pistachio, 

black walnut, and English or Persian 

walnut)

0.14 3 0.34 14 G*, A, 

Airblast

7

Hops 0.10 2 0.2 14 G*, A, 

Airblast

7

Christmas Tree Plantations 0.16 2 0.32 14 G*, A, 

Airblast

N/A
16

Table A-1. Summary use information for spirotetramat based on labels for BYI 8330 150 OD 

Insecticide), MOVENTO®and ULTOR®. The new uses are shaded yellow.

USE

SINGLE 

APP. RATE 

(lb. a.i./A)

NUMBER 

OF APPS.

SEASONAL 

APP. RATE 

(lb. a.i./A)

INTERVAL 

BETWEEN 

APPS. (days)

APP.

METHOD

PHI 

(days)

Fruiting Vegetables (Crop 

Group 8-10 including eggplant, 

groundcherry, okra, pepinos, bell 

and non-bell pepper (cayenne, chili 

pepper, habanero, jalapeno, pablano, 

pimento and serranero), tomatillo,

tomato, African eggplant, Bush 

tomato, cocona, currant tomato, 

garden huckleberry, goji berry, 

martynia, naranjilla, pea eggplant, 

roselle, scarlet eggplant, sunberry, 

tree tomato, including varieties and/ 

or hybrids of these commodities)

0.08 2 0.16 7 G, A, C 1

Leafy Vegetables (Crop Group 4

including amaranth-various kinds, 

arugula-roquette, cardoon, celery, 

celtuce, chervil, Chinese celery, 

chrysanthemum, corn salad, garden 

cress, cress-various kinds, 

dandelion, sorrel dock, endive, 

Florence fennel, lettuce-head and 

leaf, orach, parsley, garden and 

winter purslane, radicchio or red 

chicory, rhubarb, spinach-various 

kinds, Swiss chard, taro leaves)

0.08 2 0.16 7 G, A, C 3

Brassica (Cole) Leafy 

Vegetables (Crop Group 5

including broccoli, broccoli raab, 

Brussels sprouts, cabbage, 

cauliflower, cavalo broccolo, 

Chinese broccoli, Chinese cabbage

(bok choy), Chinese cabbage (napa), 

Chinese mustard cabbage (gai 

choy), collards, kale, kohlrabi, 

mizuna, mustard greens, mustard 

spinach, rape greens)

0.08 2 0.16 7 G, A, C 1

Potato and Other Tuberous and 

Corm Vegetables (Crop 

Subgroup 1C including arracacha, 

arrowroot, Chinese and Jerusalem 

artichoke, edible canna, bitter and 

sweet cassava, chayote-root, chufa, 

dasheen or taro, ginger, leren, 

potato, sweet potato, tanier, 

turmeric, yam bean, true yam)

0.08 2 0.16 7 G, A, C 7
17

Table A-1. Summary use information for spirotetramat based on labels for BYI 8330 150 OD 

Insecticide), MOVENTO®and ULTOR®. The new uses are shaded yellow.

USE

SINGLE 

APP. RATE 

(lb. a.i./A)

NUMBER 

OF APPS.

SEASONAL 

APP. RATE 

(lb. a.i./A)

INTERVAL 

BETWEEN 

APPS. (days)

APP.

METHOD

PHI 

(days)

Bushberry and Low Growing 

Berry Subgroups (Crop 

Subgroups 13-07B and 13-07H

including aronia berry, bearberry, 

bilberry, blueberry (highbush and 

lowbush), Chilean guava, 

cloudberry, cranberry, currant 

(black, buffalo, native, and red), 

elderberry, European barberry, 

gooseberry, edible honeysuckle, 

jostaberry, Juneberry, muntries, 

lingonberry, Partridgeberry, salal, 

sea buckthorn, and cultivars, 

varieties, and/or hybrids of these)

0.16 3 0.47 7 G*, A, 

Airblast

7

Watercress 0.2 2 0.4 7 G, A, C 3

Banana and Plantains 0.25 5 1.25 14 G*, A, 

Airblast

1

Coffee 0.16 3 0.47 21 G*, A, 

Airblast

14

Pineapple 0.16 2 0.32 14 G*, A, 

Airblast

1

Pomegranate 0.16 2 0.32 14 G*, A, 

Airblast

1

Bulb Vegetables

Crops of Crop Subgroup 3-07A

(including: daylily (bulb), fritillaria 

(bulb), garlic (bulbs of common, 

great-headed, serpent), lily (bulb), 

onion (bulbs of common, Chinese, 

pearl, potato onion), shallot (bulb), 

plus cultivars, varieties, and/or 

hybrids of these);

Crops of Crop Subgroup 3-07B, 

(including: Chinese chive (fresh 

leaves), chive (fresh leaves), elegans 

hosta, fritillaria (leaves), kurrat, leek 

(Allium porrum, Lady’s, wild), 

onion (Beltsville bunching, fresh, 

green, macrostem, tree [tops], welsh 

[tops]), shallot (fresh leaves), plus 

cultivars, varieties, and/or hybrids of 

these)

0.08 2 0.16 7 G, A, C 3 for CS 

3-07A;

7 for CS 

3-07B

*High air velocity, low volume or air curtain sprayers; G = ground; A = aerial; C = chemigation
18

Appendix B. Aquatic Exposure Assessment for the New Uses of Spirotetramat 

2012

I. Conventional Agricultural Crops

Approach to Model Conventional Crops

For agricultural uses, exposure concentrations for aquatic ecosystems assessments were 

estimated based on EFED’s Tier II linked aquatic model PRZM/EXAMS. A graphical user 

interface (PE5 v. 5.0, November 15, 2006), developed by the EPA 

(http://www.epa.gov/oppefed1/models/water/index.htm, accessed 07/20/2012), was used to 

facilitate inputting chemical and use specific parameters into the appropriate PRZM input files 

(inp) and EXAMS chemical files. The Pesticide Root Zone Model (PRZM v. 3.12.2, May 12, 

2005) field or orchard crop scenario is the basic file which describes the local or regional 

climatological information, soil hydrology, soil characteristics, crop characteristics, and the 

pesticide properties necessary to determine pesticide loadings to ground or surface water. This 

basic file constitutes the first part of the “exposure scenario.” It simulates the processes in the 

agricultural field, such as runoff and erosion, on a daily time step. The runoff and erosion flux 

output data from PRZM are used as chemical loadings to the Exposure Analysis Modeling 

System (EXAMS v. 2.98.04.06, April 25, 2005), which simulates surface water, in order to 

predict the estimated exposure concentrations (EECs). EECs for ecological risk assessment were 

determined using a pond modeling scenario which describes a standard scenario for the EXAMS 

component of the modeling exercise (EXAMS Mississippi pond). Tables B1-1 and B1-2

summarize the input parameters for spirotetramat and for the total residues of concern (total toxic 

residues or TTR). The estimated exposure concentrations are summarized in Tables B1-3.

Selection of PRZM scenarios

The PRZM scenarios selected for modeling were CA row crops, OR berries, PR coffee and FL 

citrus. These crops were selected to represent artichoke, bushberries and low growing berries, 

coffee, and bananas and plantains, respectively. An effort was made to model representative 

crops among the crops in the label with the highest seasonal application rate. Information from 

the Census of Agriculture shows that by far California is the greatest producer of artichokes. 

Other states with reported production are Arizona, Hawaii, Oregon, Texas and Washington. The 

CA row crops scenario was considered the most suitable to represent the artichoke crop. OR was 

among the top five producers of blueberries in 2010 and 2011 and it had the third highest 

harvested area in 2010 and 2011 (refer to Tables 02 and 06 of the USDA data at 

http://usda.mannlib.cornell.edu/MannUsda/viewDocumentInfo.do?documentID=1765 (accessed 

07/20/2012). Even though the OR berries scenario was initially intended for organophosphate 

assessments, it was regarded as a good representative scenario for bushberries and low growing 

berries. The PR coffee scenario was used to represent the intended crop. Only two US states 

and territories appear to produce coffee (according to the 2007 Census of Agriculture, 37,422 

acres in PR and 7,891 acres in HI). Finally, there was no PRZM/EXAMS scenario for bananas 

and plantains, which were the crops with the highest application rate. According to the Census 

of Agriculture, in 2009 and 2010, 1,100 acres were harvested (bananas) in HI. Meanwhile, in PR 

17,500 acres were planted to plantains and 6,810 acres were planted to bananas in 2007. In order 

to appropriately represent this crop that may be planted year round, the FL citrus scenario was 
19

utilized. It has a south FL climate (West Palm Beach) and well drained sandy soil. Since the 

EECs were well below the LOCs, runs with additional weather stations were not deemed 

necessary. It is noted that the FL citrus scenario was used in a past assessment to represent the 

intended crop (i.e., citrus crops). In that instance in contrast, the application rate was much 

smaller (0.16 lb a.i./A, two applications at 21 day intervals and applications made in the month 

of November).

Input Parameters

Maximum seasonal application rates were utilized, with the minimum interval between 

applications. There is no usage data because these are new crops for spirotetramat. It is 

unknown if these rates will be representative of the typical application rates; nevertheless, they 

represent a conservative estimate. Applications were assumed to occur during the mid to end of 

the crop season (it was presumed that during this time period foliage was present, since this 

chemical is efficacious when applied to foliage). For bananas and plantains, applications were 

assumed to occur in the summer. For all the crops and crop scenarios, runs were performed for 

the parent compound, spirotetramat. For the crop that yielded the highest estimated exposure 

concentrations (EECs), an additional run was performed for the total toxic residues 

(spirotetramat + spirotetramat-enol + spirotetramat-ketohydroxy + non-extracted residues), 

consistent with previous assessments.

Only the aerial method of application was modeled. For spirotetramat (Table BI-1), the average 

Kd was a better descriptor of the mobility of the parent (i.e., the coefficient of variation is smaller 

for Kd than for KOC). The aerobic and anaerobic aquatic metabolism half-lives were not adjusted 

for hydrolysis. The aerobic aquatic metabolism values for spirotetramat were 1.05 and 1.06 days 

vs. 13.1 days for hydrolysis at pH 7 and 20°C (the actual value was 0.26 days when adjusted for 

temperature at 250C). The average pH of the water in the studies ranged from 6.7 – 7.3. The 

anaerobic aquatic metabolism value is 2.8 days and the pH range in the water phase was 7.7-7.9, 

increasing to 8.2-8.3 by the end of the study. Since the hydrolysis is dependent upon the pH and 

the reaction is faster at pH 9 (0.32 days at 25°C), the hydrolysis may have played a role in the 

degradation of spirotetramat. However, the extent of such reaction is unknown. The actual input 

parameter, when adjusted for temperature at 250C is 0.70 days x 3 (factoring that there is only 

one value) = 2.1 days.

As indicated above, one PRZM/EXAMS run was set for the total residues of spirotetramat + 

spirotetramat-enol + spirotetramat-ketohydroxy + un- or non-extracted residues, which were 

considered of concern (Table BI-2). The soils and sediments may also be repositories of toxic 

residues since high levels of non-extracted residues were observed in metabolism studies (up to 

60% of AR). The total residues of spirotetramat, spirotetramat-enol, spirotetramat-ketohydroxy 

and non-extracted residues are much more persistent than the parent or its major metabolites 

considered alone. Half-lives (t1⁄2’s) of 161-204 days were estimated from the aerobic soil 

metabolism studies for spirotetramat-enol + spirotetramat-ketohydroxy + non-extracted residues; 

while half-lives of 141-693 days (prior to adjusting to temperature of 250C), were estimated from 

the aerobic aquatic metabolism studies for spirotetramat + spirotetramat-enol + spirotetramatketohydroxy + non-extracted residues. The registrant indicated that the non-extracted residues 

were immobile and not accessible; this issue is explored with more detail later in this appendix. 
20

A conservative approach was taken and for the half-life calculation, it was assumed that the nonextracted residues were persistent compounds.

The crop selected for modeling the total toxic residues (TTR), was the FL citrus, which

represents bananas and plantains, with the highest seasonal application rate and the most 

conservative application method and the highest EECs. For the total residues (TTR), the average 

KOC value (from the study of spirotetramat-ketohydroxy), was taken as a better descriptor of the 

mobility of the total residues since spirotetramat-ketohydroxy appears to be the most stable of

the chemicals of concern. Also, for the total residues, the representative half-lives were obtained 

by adding the values of the concentrations of the parent, spirotetramat-enol, spirotetramatketohydroxy and non-extracted residues, and calculating the half-life of the decay of their sum. 

In those cases where one of the metabolites was stable, or no data were available, a conservative 

approach was taken and it was assumed that the TTR were stable (e.g. spirotetramat-enol was 

found to be stable to hydrolysis, therefore, the TTR were considered to be stable to that route of 

degradation). The aerobic soil metabolism input parameter was estimated for the total residues 

of spirotetramat-enol + spirotetramat-ketohydroxy + non-extracted residues (from the aerobic 

soil metabolism study conducted with spirotetramat-enol). Similarly, the aerobic aquatic 

metabolism input parameter was estimated for the total residues of spirotetramat + spirotetramatenol + spirotetramat-ketohydroxy + non-extracted residues. The water solubility of 

spirotetramat-ketohydroxy was considered the most adequate input parameter for the TTR, since 

it is the last degradate in the pattern of formation and decay. Since spirotetramat amide was a 

minor degradate, it was not considered in the modeling.

1

There is a relatively high degree of certainty on the input parameters for the runs for the parent 

only. The database was substantially complete. In some instances multiple values were 

available, from which the input values were derived (e.g. for aerobic aquatic metabolism – two 

half-lives were available, and for aerobic soil metabolism – four half-lives were available). In 

other instances, the available value was multiplied by three to account for the uncertainty due to 

the fact that there was only one value. (e.g. anaerobic aquatic metabolism – 8.4 days, from 3 x 

2.8 days, subsequently corrected for temperature). For the aqueous photolysis, the single value 

available was entered – 14.4 days. For the parent, there are various routes of dissipation. This is 

reflected in the input parameters in PRZM/EXAMS (input values 0.298 days for aerobic soil 

metabolism, 0.2676 days for aerobic aquatic metabolism, 2.1 days for anaerobic aquatic 

metabolism, 13.1 days for hydrolysis, and 14.4 days for aqueous photolysis). Note that the 

aerobic aquatic metabolism and anaerobic aquatic metabolism input values were adjusted for 

temperature at 250C. On the other hand, the total residues (spirotetramat + spirotetramat-enol + 

spirotetramat-ketohydroxy) were assumed to be stable to hydrolysis, aqueous photolysis and 

anaerobic aquatic metabolism (the most conservative case). These residues appeared to degrade 

relatively slowly, compared to the parent alone (input values 222.3 days for aerobic soil 

metabolism and 140.9 days for aerobic aquatic metabolism). Table BI-1 provides the input 

parameters for the parent compound.

 

1 The registrant submitted their own modeling calculations including the degradate; however, EFED did not consider 

it necessary.
21

Table BI-1. Input Parameters for PRZM/ EXAMS for the Estimation of the EECs of Spirotetramat

Parameter (units) Value(s) Sources Comments/ Other

Output File Name SPIROTET --- ---

Chemical Name Spirotetramat Label Proposed labels

Crop Names CA row crops

OR berries

PR coffee

FL citrus

Label Proposed labels: CA row crops represents 

globe artichoke while OR berries represents 

bushberries and low growing berries and FL 

citrus is used as a surrogate for bananas

Application Rate Crop/ lb a.i./A/ kg a.i./ha

CA row crops/ 0.10/ 0.1121

OR berries/ 0.16/ 0.1793

PR coffee/ 0.16/ 0.1793

FL citrus/ 0.25/ 0.2808

Label For globe artichoke, the single max 

application rate is 0.12. In order to 

accommodate the max seasonal rate, five 

applications at 0.10 lb a.i./A were assumed.

Day of Application (day-month)/ 

pre-harvest interval

CA row crops 10-02

OR berries 10-05

PR coffee 01-06

FL citrus 01-05

PHI (days):

CA row crops 3

OR berries 7

PR coffee 14

FL citrus 1

Estimated from metadata file & labels.

Crop emergence/ maturity/ harvest day-mo:

CA row crops 01-01/ 01-04/ 08-04

OR berries 01-04/ 30-07/ 30-07

PR coffee 01-01/ 02-01/ 31-12

FL citrus 01-01/ 02-01/ 31-12

Maximum Number of 

Applications Allowed at the 

Maximum Application Rate

CA row crops 5

OR berries 3

PR coffee 3

FL citrus 5

Label Proposed labels

Minimum Interval between 

Applications (days)

CA row crops 7

OR berries 7

PR coffee 21

FL citrus 14

Label Proposed labels

CAM (Chemical application 

method)

2 Label 2, linear foliar based on crop canopy

IPSCND (Flag indicating the 

disposition of pesticide remaining 

on foliage after harvest)

1 Input Parameter 

Guidance

1, pesticide remaining on foliage is 

converted to surface application to the top 

soil layer

DEPI = Incorporation Depth (cm) 0.0 Label Proposed labels

Kd (mL/g) 4.39 OECD Monograph 

Annex B. 

Spirotetramat. B.8 Fate 

and Behaviour

The average Kd value, as per current EFED 

guidance on input parameters for PRZM/

EXAMS. The Kd value represents better the 

mobility of spirotetramat (relative standard 

deviation is smaller).

Aerobic Soil Metabolism (days) 0.298 OECD Monograph 

Annex B. 

Spirotetramat. B.8 Fate 

and Behaviour

Represents the 90th percentile of the upper 

confidence bound on the mean of four halflife values (FL sandy loam; t1/2 = 0.30 days, 

sandy loam; t1/2 = 0.24 days, silty loam; t1/2 = 

0.26 days, silt; t1/2 = 0.09 days) (DFOP best 

fit kinetics).

Method of Application Aerial Label Proposed labels

Buffer Zone (ft.) N/A Label Proposed labels

Application Efficiency (fraction) 0.95 for aerial application --- EFED guidance

Spray Drift (fraction) 0.05 for aerial application --- EFED guidance

Solubility in Water (ppm) 33.5 OECD Monograph 

Annex B. 

Spirotetramat. B.8 Fate 

and Behaviour

EFED guidance

Aerobic Aquatic Metabolism 

(days)

0.2676 OECD Monograph 

Annex B. 

Spirotetramat. B.8 Fate 

and Behaviour

Represents the 90th percentile of the upper 

confidence bound on the mean of two halflife values at 200C (loam sediment; t1/2 =1.06 

days, loamy sand sediment; t1/2 =1.05 days) 

(SFO kinetics). Adjusted values at 250C: 

0.265 days and 0.2625 days, mean 0.26375, 

std. dev. 0.00178 days, t90,n-1 = 3.078.

Anaerobic Aquatic Metabolism 

(days)

2.1 OECD Monograph 

Annex B. 

Spirotetramat. B.8 Fate 

and Behaviour

Determined by multiplying the available 

half-life (2.8 days) by 3 to account for the 

uncertainty associated with using a single 

value (SFO kinetics). Since the value was 

obtained at 200C, it was adjusted to 250C 

(0.70 days x 3 = 2.1 days).

Hydrolysis at pH 7 half-life (days) 13.1 OECD Monograph 

Annex B. 

EFED guidance (SFO kinetics).
22

Table BI-1. Input Parameters for PRZM/ EXAMS for the Estimation of the EECs of Spirotetramat

Parameter (units) Value(s) Sources Comments/ Other

Spirotetramat. B.8 Fate 

and Behaviour

Aqueous Photolysis @ pH 7 

(days)

14.4 OECD Monograph 

Annex B. 

Spirotetramat. B.8 Fate 

and Behaviour

t1/2 = 14.4 Phoenix, AZ days, maximum 

dark-controlled available value (SFO 

kinetics).

Molecular Weight (g/mole) 373.45 OECD Monograph 

Annex B. 

Spirotetramat. B.8 Fate 

and Behaviour

---

Vapor Pressure (torr or mmHg) 4.2x10-11 OECD Monograph 

Annex B. 

Spirotetramat. B.8 Fate 

and Behaviour

---

Henry’s Law Constant

(Atm-m

3

/mol)

6.90x10-13 OECD Monograph 

Annex B. 

Spirotetramat. B.8 Fate 

and Behaviour

---

Environment pond298.exv --- Default for pond scenario, as opposed to 

Field Size EPA Pond --- index reservoir.

Runoff none --- ---

FEXTRC, Foliar extraction 0.5 --- EFED guidance

PLDKRT, Decay rate on foliage 0 --- EFED guidance

PLVKRT, Volatilization rate from 

foliage

0 --- EFED guidance

UPTKF, Uptake factor 0 --- EFED guidance

Write Benthic Pore Water 

Concentrations?

Yes --- For information only

Table BI-2 provides the input parameters for the TTRs.

Table BI-2. Input Parameters for PRZM/EXAMS for the Estimation of the EECs of Spirotetramat + 

Degradates (Total Residues: Spirotetramat + Spirotetramat-enol + Spirotetramat-ketohydroxy + NonExtracted Residues) for a Representative Crop With the Highest EECs: FL citrus (bananas and plantains)

Parameter (units) Value(s) Sources Comments

Output File Name SPIROTET --- ---

Chemical Name Spirotetramat Label Proposed labels

Crop Names FL citrus Label Proposed labels (represents bananas and 

plantains – crop with the highest EECs using 

the parent only.

Application Rate Crop/ lb a.i./A/ kg a.i./ha

FL citrus/ 0.25/ 0.2808

Label Proposed labels

Day of Application (day-month)/ 

pre-harvest interval

FL citrus 01-05

PHI (days):

FL citrus 1

Estimated from metadata file & labels.

Crop emergence/ maturity/ harvest day-mo:

FL citrus 01-01/ 02-01/ 31-12

Maximum Number of 

Applications Allowed at the 

Maximum Application Rate

FL citrus 5 Label Proposed labels

Minimum Interval between 

Applications (days)

FL citrus 14 Label Proposed labels

CAM (Chemical application 

method)

2 Label 2, linear foliar based on crop canopy

IPSCND (Flag indicating the 

disposition of pesticide remaining 

on foliage after harvest)

1 Input Parameter 

Guidance

1, pesticide remaining on foliage is 

converted to surface application to the top 

soil layer

DEPI = Incorporation Depth (cm) 0.0 Label Proposed labels

KOC (mL/gOC) 65.32 OECD Monograph 

Annex B. 

Spirotetramat. B.8 Fate 

and Behaviour

The average KOC value, as per EFED 

guidance on input parameters for 

PRZM/EXAMS. The KOC value represents 

better the mobility of spirotetramatketohydroxy, the terminal degradate and the 
23

Table BI-2. Input Parameters for PRZM/EXAMS for the Estimation of the EECs of Spirotetramat + 

Degradates (Total Residues: Spirotetramat + Spirotetramat-enol + Spirotetramat-ketohydroxy + NonExtracted Residues) for a Representative Crop With the Highest EECs: FL citrus (bananas and plantains)

Parameter (units) Value(s) Sources Comments

most stable (relative standard deviation is 

smaller).

Aerobic Soil Metabolism (days) Total Residues 222.3 days OECD Monograph 

Annex B. 

Spirotetramat. B.8 Fate 

and Behaviour

Represents the 90th percentile of the upper 

confidence bound on the mean of four halflife values for the total residues of the enol 

and the ketohydroxy (all possible significant 

figures used, use of log-linear parameters) 

(t1/2 = 203.82 days, t1/2 = 169.02 days, t1/2 = 

161.16 days, t1/2 = 203.82 days; mean = 

184.455 days; std. dev. 22.58984 days).

Method of Application Aerial Label Proposed labels

Buffer Zone (ft.) N/A Label Proposed labels

Application Efficiency (fraction) 0.95 for aerial application --- EFED guidance

Spray Drift (fraction) 0.05 for aerial application --- EFED guidance

Solubility in Water (ppm) 228 OECD Monograph 

Annex B. 

Spirotetramat. B.8 Fate 

and Behaviour

EFED guidance

Aerobic Aquatic Metabolism 

(days)

Total Residues 140.9 days OECD Monograph 

Annex B. 

Spirotetramat. B.8 Fate 

and Behaviour

For the parent + enol + ketohydroxy, 

represents the 90th percentile of the upper 

confidence bound on the mean of four halflife values 385.00; 693.00, 141.43, 256.67 

days at 200C, which are adjusted to 250C: 

96.25, 173.25, 35.36, and 64.17 days; std. 

dev = 59.447 days, mean = 92.26 days (used

of log-linear parameters).

Anaerobic Aquatic Metabolism 

(days)

OVERALL – Stable OECD Monograph 

Annex B. 

Spirotetramat. B.8 Fate 

and Behaviour

The enol is stable and there are no adequate 

data on the ketohydroxy; the most 

conservative scenario is presumed.

Hydrolysis at pH 7 half-life (days) OVERALL – Stable OECD Monograph 

Annex B. 

Spirotetramat. B.8 Fate 

and Behaviour

The enol is stable and there are no adequate 

data on the ketohydroxy; the most 

conservative scenario is presumed.

Aqueous Photolysis @ pH 7 

(days)

OVERALL – Stable OECD Monograph 

Annex B. 

Spirotetramat. B.8 Fate 

and Behaviour

The enol and the ketohydroxy are not 

photodegradates; therefore, in the absence of 

data, the most conservative scenario is 

presumed.

Molecular Weight (g/mole) 373.45 OECD Monograph 

Annex B. 

Spirotetramat. B.8 Fate 

and Behaviour

Assumed to be the one for the parent.

Vapor Pressure (torr or mmHg) 4.2x10-11 OECD Monograph 

Annex B. 

Spirotetramat. B.8 Fate 

and Behaviour

Assumed to be the same than for the parent, 

due to similar structures.

Henry’s Law Constant

(Atm-m

3

/mol)

6.90x10-13 OECD Monograph 

Annex B. 

Spirotetramat. B.8 Fate 

and Behaviour

Assumed to be the same than for the parent, 

due to similar structures.

Environment pond298.exv --- Default for the standard pond scenario, as 

Field Size EPA Pond --- opposed to index reservoir.

Runoff none --- ---

FEXTRC, Foliar extraction 0.5 --- EFED guidance

PLDKRT, Decay rate on foliage 0 --- EFED guidance

PLVKRT, Volatilization rate from 

foliage

0 --- EFED guidance

UPTKF, Uptake factor 0 --- EFED guidance

Write Benthic Pore Water 

Concentrations?

Yes --- For information only
24

The modeling results using PRZM/EXAMS are presented in Table BI-3,

Table BI-3. Estimated exposure concentrations of spirotetramat (parent only) in 

the water column. Artichoke (represented by CA row crops), bushberries and low 

growing berries (represented by OR berries), bananas (represented by FL citrus), 

and coffee (PR coffee) calculated with PRZM/ EXAMS.2

Crop Scenario/App. 

rate/No. Apps/Int. 

Between Apps. Peak/ppb 21-day/ppb 60-day/ppb

CA row crops

0.10/ 5/ 7 0.284 0.0464 0.0265

OR berry

0.16/ 3/ 7 0.449 0.0658 0.0230

PR coffee

0.16/ 3/ 21 0.491 0.0197 0.0155

FL citrus

0.25/ 5/ 14 1.46 0.0622 0.0462

TTR = total toxic residues = spirotetramat + spirotetramat-enol + spirotetramat-ketohydroxy + NERs

For the parent spirotetramat, the FL citrus scenario yielded peak EECs that were higher by a 

factor of around 3. These results are consistent with the higher application rate for bananas and 

plantains. Since the chemical is labile, the 21-day and 60-day EECs were much lower than the 

peak EECs. It is noted that this pattern is not followed by the NC apples (previously assessed 

crop), since when it was modeled, the guidance for temperature adjustment for the aerobic and 

anaerobic aquatic metabolism input values had not been implemented. Since these studies were 

conducted at 200C, the input half-lives, adjusted to 250C are lower than in the previous 

assessment and as a consequence, the long term values decrease faster than previously modeled.

In contrast, because the TTR are relatively persistent to most of the routes of degradation and 

metabolism, the EECs do not decrease as quickly as for the parent only (see Table BI-4).

Table BI-4. Estimated exposure concentrations of spirotetramat TTR in the water 

column calculated with PRZM/ EXAMS. Bananas (represented by FL citrus), is 

the scenario that yielded the highest EECs when modeling the parent only (see 

previous table).3

Crop Scenario/App. 

rate/No. Apps/Int. 

Between Apps. Peak/ppb 21-day/ppb 60-day/ppb

FL citrus TTR

0.25/ 5/ 14 19.6 18.7 17.5

 

2 All values are rounded to three significant figures.

3 All values are rounded to three significant figures.
25

II. Aquatic Crops

Approach to Modeling Aquatic Crops

Watercress

Watercress is typically grown in clean, flowing water, 2 to 3 inches deep.4 The Agency does not 

currently have a methodology for exposure assessment for crops cultivated in flowing water, 

such as watercress. The Tier 1 Rice model v.1.05 was, therefore, used as the basis of the 

assessment of surface waters, and the results were characterized to reflect differences between 

the capabilities of this model and the watercress cultivation practices. Watercress is a very minor 

use (<700 acres were harvested in 2002 and 2007 across the U.S. and there were <65 farms, 

according to the U.S. Census of Agriculture, National Agricultural Statistics Service, U.S. 

Department of Agriculture). Based on a previous review, and according to information provided 

by the registrant and IR-4, it appears that according to agricultural practices, watercress is grown 

in a bed of water which drains to a ditch which is constantly recirculated.6 (In Florida, as per the 

Florida Department of Agriculture and Consumer Services Section 18 request, field plots are 4-

acres sized each and laser leveled. Refer also to the Section 18 for the use on watercress in 

Florida, DP Barcode D399575, which is dated 04/05/2012.) The circulation of water is stopped 

24 hours before and is started 24 hours after chemical applications.

EFED is concerned primarily about the total toxic residues (TTR), as opposed to the parent 

chemical per sé, or the individual metabolites (spirotetramat-enol, spirotetramat-ketohydroxy

and non-extracted residues), from discharge towards adjacent bodies of water likely to occur at 

the end of the season. EFED does not have a standard model for applications on watercress. As 

indicated above, in order to represent the proposed use on watercress, the Tier 1 Rice model 

v.1.0 was provisionally used (USEPA 2007, see footnote). Individual metabolites were not 

modeled because this would double count mass of pesticide and transformation products in this 

particular model. The simplified equation for the Tier 1 Rice Model v.1.0 is as follows:

Equation B1

 Where:

Cw = EEC = water concentration [μg/L or ppb]

mai' = mass applied per unit area [kg/ha] (i.e., the seasonal application rate)

Kd = water-sediment partitioning coefficient [L/kg]

 

4 E.g., see http://www.naturesherbal.com/Watercress.htm; see also http://www.bwqualitygrowers.com/ourfarms.aspx

(accessed 07/12/2012)

5 U.S. Environmental Protection Agency 2007. Guidance for Tier I Estimation of Aqueous Pesticide Concentrations 

in Rice Paddies (dated 05/08/2007). Available at http://www.epa.gov/oppefed1/models/water/rice_tier_i.htm

(accessed 07/17/2012).

6

Per information provided by the registrant in email from John Bell (Product Development Manager, Bayer

CropScience) to Laura Nollen (Chemical Review Manager, Registration Division), dated 07/16/2012.
26

For the applications of spirotetramat on watercress, the EEC expression is based on 

spirotetramat-ketohydroxy, which is the last and more persistent metabolite of the degradation 

pathway:

Spirotetramat  Spirotetramat-enol  Spirotetramat-ketohydroxy ( NERs)

For spirotetramat, the calculation is therefore:

Where the input parameters selected for the model and their justification and sources are 

specified in Table BII-1.

Table BII-1. Tier I Rice Model v1.0 input parameters for spirotetramat use on watercress

Input 

Parameter Value Justification Source

Application Rate 

(mai')

0.44832 0.20 lb a.i./A/application x 2 applications = 0.4 lb 

a.i./A (x 1.1208 Kg·A/ha·lb) = 0.44832 kg a.i./ha

Proposed spirotetramat 

labels

Soil-to-Water 

Partition Coefficient 

(Kd)

0.6532

Kd = Mean KOC (65.32 L/Kgoc) x 1% organic carbon 

content = 0.6532 L/kg for the total spirotetramat 

residues1

OECD Monograph Annex 

B. Spirotetramat. B.8 Fate 

and Behaviour

1. The representative partition coefficient used is the one for spirotetramat-ketohydroxy, which is the last metabolite 

in the degradation sequence and for which the KOC model is more suitable than the Kd model (i.e., the coefficient of 

variation is smaller).

Assumptions of the Tier 1 Rice Model v.1.0 (Provisionally Used for Watercress)

Most of the assumptions used in the Tier 1 Rice Model v.1.0 model help ensure that the 

outputs are protective of most environments associated with rice agriculture (noted though, that it 

is provisionally being used to represent the uses on watercress). Rice cultivation differs from 

watercress in that for the latter the water is constantly flowing while for rice, the field is flooded. 

The model assumptions include the following (see USEPA 2007, referenced in a footnote, for 

parameterization information and further details):

1. Movement of pesticide on suspended sediment is not considered (while for this use, water 

is constantly circulated except when pesticides are applied; the water circulation may 

promote pesticide movement).

2. Degradation does not occur (notwithstanding, the TTR are relatively persistent to aerobic 

aquatic metabolism and moderately persistent to aerobic soil metabolism).

3. Volatilization and other dissipation processes are not considered (for spirotetramat, the 

vapor pressure and Henry’s Law Constant are low, indicating a low potential for 

volatilization, but other dissipation processes like degradation and metabolism are not 

considered).

4. The partitioning to sediment is instantaneous.
27

5. Water is available for non-target animal exposure instantaneously (because the chemical 

is likely circulated, it appears that the water would be discharged into adjacent bodies of 

water and would be of concern primarily at the end of the season).

6. Water column depth is 10 cm. (Based upon unofficial data, it appears that actual depth is 

in the range of 1 to 3 inches or around 2.5 to ~8 cm). As per the registrant, chemical 

applications occur 24 hours after water circulation is stopped and water circulation is 

restarted 24 hours after application.)

7. Sediment depth is 1 cm.

8. All pore space is saturated with water.

9. Organic carbon fraction is 0.01 (i.e., 1% OC).

10. Bulk density is 1300 kg/m3.

11. Grain density is 2650 kg/m3.

The aerobic soil half-life for the TTR is on the order of 222.3 days and their partitioning is not 

too strong with a KOC of 65.32 L/KgOC (mobile according to FAO mobility classification, FAO

20007, using spirotetramat-ketohydroxy as the representative chemical). The aerobic soil 

metabolism half-life for spirotetramat TTR is 140.9 days. It is noted that neither the degradation 

of the pesticide nor the mass transfer from the aqueous phase to the sediment are considered in 

this conceptualization, which greatly simplifies the model. The absence of degradation adds 

conservatism to the model (i.e., estimated concentrations should be higher than those usually 

found in rice paddies, considered representative of use on watercress). The absence of mass 

transfer processes can either add or reduce conservatism depending on numerous conditions such 

as whether the pesticide is soil or water applied and whether actual degradation occurs 

preferentially in the sediment or the water compartment; however, consideration of this 

parameter is a refinement beyond a Tier 1 conceptualization. Spirotetramat is actually foliarly 

applied and the chemicals (spirotetramat, spirotetramat-enol and spirotetramat-ketohydroxy) do 

not readily bind to bottom sediment. The nature of the non-extracted residues is uncertain.

Refinements to the Tier 1 Rice Model v.1.0

In order to refine the results, and due to expected exceedances of the acute LOCs, the rice model, 

provisionally used for this crop, was modified in order to accommodate degradation and/or 

metabolism. Thus, the aerobic soil and the aerobic aquatic metabolism were incorporated. The 

former is assumed to occur only for a period of 1 day for each application (prior to flooding), and 

the latter is assumed to occur from the time of the last application. The results of the modeling 

watercress are presented in Table BII-2a.

Cranberry

For cranberry, similar refinements over the provisional Tier I Rice Model v.1.0 were performed. 

Cranberry bogs are not typically flooded until the night before harvesting. According to the 

Cranberry Institute site8, “[t]he plant produces stolons (horizontal stems) up to 6 feet (2 m) long. 

Short vertical branches, or uprights, 2 to 8 inches (5 to 20 cm) in height, grow from buds on the 

 

7

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 (accessed 07/17/2012).

8 Available at http://www.cranberryinstitute.org/about_cranberry.htm (accessed 07/25/2012).
28

stolons and these can be either vegetative or fruiting.” When cranberry fields are flooded, the 

water depth is typically 12-18 in (0.305-0.457 m) to cover the plants with water above the vine. 

The lowest value was selected, since it is more conservative. The results of the modeling 

cranberries are presented in Table BII-2b.

Modeling Results Using the Modified Tier 1 Rice Model v.1.0

For both, watercress and cranberry, the parent only was modeled. Furthermore, the total residues 

of spirotetramat (spirotetramat + spirotetramat-enol + spirotetramat-ketohydroxy + NERs) were 

modeled. Finally, for characterization purposes, the total residues, excluding the NERs were 

calculated. In all instances, applications were assumed to occur 1 day pre-flood. According to 

the label, the proposed pre-harvest interval is 7 days. It is noted that the registrant indicated 

previously that for cranberry, they could put restrictions in their labels, limiting applications to a 

pre-flooding interval of 30 days. Therefore, the EFED evaluated for additional characterization, 

the total residues with a period of 30 days pre-flood.

Table BII-2a. Estimated exposure concentrations of spirotetramat (ppb) in the 

water column. Watercress use, calculated with the modified Tier 1 Rice model 

v.1.0.9

Crop Scenario/App. 

rate/No. Apps/Int. 

Between Apps. Peak/ppb 21-day/ppb 60-day/ppb

Spirotetramat only

0.2/ 2/ 7 38.6 1.99 0.695

TTR + NERs

0.2/ 2/ 7 393 381 359

TTR (excluding the 

NERs)

0.2/ 2/ 7

373 361 338

TTR with and without NERs = total toxic residues = spirotetramat + spirotetramat-enol + spirotetramat-ketohydroxy 

with and without NERs. One day pre-flood was assumed in all instances.

The aerobic aquatic metabolism half-life value for the TTR excluding the NERs was assumed to 

be the same than for spirotetramat-ketohydroxy since it is the most persistent of the degradates 

and the last one in the degradation sequence. Furthermore, it is the rate determining step.

For watercress, since the time pre-flood is 1 day (considered fixed), the peak EECs were not 

considered to vary substantially for the TTR; however, since the parent compound is very labile, 

the peak EECs were around one order of magnitude smaller. For cranberry, there was substantial 

variability between the TTR which included the NERs vs. the TTR which excluded the NERs. 

The discussion of the EECs is relatively limited because there was concern of exceedances of the 

LOCs only for the peak EECs.

 

9 All values are rounded to three significant figures.
29

Table BII-2b. Estimated exposure concentrations of spirotetramat (ppb) in the water 

column. Cranberry use (a member of the bushberry and low growing berries group), 

calculated with the modified Tier 1 Rice model v.1.0.10

Crop Scenario/App. rate/No. 

Apps/Int. Between Apps. Peak/ppb 21-day/ppb 60-day/ppb

Spirotetramat only

0.16/ 3/ 7 – 1 d pre-flood 5.50 0.283 0.0991

TTR + NERs

0.16/ 3/ 7 – 1 d pre-flood 162 157 148

TTR + NERs

0.16/ 3/ 7 – 30 d pre-flood 141 137 129

TTR (excluding the NERs)

0.16/ 3/ 7 – 1 d pre-flood 114 110 103

TTR (excluding the NERs)

0.16/ 3/ 7 – 30 d pre-flood 22.4 21.6 20.3

TTR with and without NERs = total toxic residues = spirotetramat + spirotetramat-enol + spirotetramat-ketohydroxy 

with and without NERs.

Provisional Tier I Rice Model Equations Used for Watercress and Cranberry

Provisional Modified Rice Model (Jones, 2006)11 Equation B2 incorporates the aerobic aquatic 

metabolism.

d

kt

ai

w

K

m e

C

0.00105 0.00013

'

Equation B2

where,

Cw = water concentration [μg/L]

t = interval since last application [d]

k = upper 90th percentile of aerobic aquatic metabolism study rate constants [1/d]

For cranberry use, the provisional Modified Rice Model water column depth was 

lengthened to a depth that is used to flood cranberry bogs (i.e., 12 inches; Cape Cod 

Cranberry Growers Association, 2001)

12

.

i.e.,

dw = water column depth = 0.305 m (for cranberry bogs)

 

10 All values are rounded to three significant figures.

11 Jones, R. 2006. Rice Screen Documentation. U.S. Environmental Protection Agency, Office of Pesticide 

Programs, Washington, DC. Feb. 21, 2006

12 Available at http://www.cranberries.org/.
30

In order to model degradation prior to the flood at harvest, the application rates for n 

number of pre-harvest applications were independently degraded over the interim until 

flooding and then summed (Equation B3).

Degradation in a Dry Bog, incorporating aerobic soil metabolism is presented in Equation B3:

n

k t

ai ai n

n m m e

1

2

' '

Equation B3

where,

mai' = mass per unit area at flood [kg/ha]

mai'n = mass applied per unit area on the nth application [kg/ha]

k2 = upper 90th percentile of aerobic soil metabolism study rate constants [1/d]

tn = interval from the nth application to harvest [d]

n = number of pre-harvest applications

These equations and parameter sets constitute the provisional Tier I Cranberry Model, 

which was similarly used to refine the use on watercress.

Provisional Tier I Cranberry and Watercress Model.

n

k t

ai ai n

n m m e

1

2

' '

Equation B4

where,

mai' = mass per unit area at flood [kg/ha]

mai'n = mass applied per unit area on the nth application [kg/ha]

k2 = upper 90th percentile of aerobic soil metabolism study rate constants [1/d]

tn = interval from the nth application to harvest [d]

n = number of pre-harvest applications

This is followed by (note that this is an expanded version of Equation B2):

w sed sed b d

kt

ai

w

d d K

m e

C 3

2

10

10 '

Equation B5

Also, if appropriate, like in this instance:

Kd01KOC 0.

Equation B6

where,

Cw = water concentration [μg/L]
31

t = interval since flood [d]

k = upper 90th percentile of aerobic aquatic metabolism study rate constants [1/d]

Kd = water-sediment partitioning coefficient [L/kg]

KOC = organic carbon partitioning coefficient [L/kg]

dw = water column depth = 0.305 m

dsed = sediment depth = 0.01 m

θsed = porosity of sediment = 0.509

ρb = bulk density of sediment = 1300 kg/m3

Sample PRZM/EXAMS Output File

stored as SPIROTET.out

Chemical: Spirotetramat

PRZM environment: CARowCropRLF_V2.txt modified Wedday, 26 March 2008 at 10:38:52

EXAMS environment: pond298.exv modified Tueday, 26 August 2008 at 06:14:07

Metfile: w23234.dvf modified Tueday, 26 August 2008 at 06:15:38

Water segment concentrations (ppb)

Year Peak 96 hr 21 Day 60 Day 90 Day Yearly

1961 0.2804 0.07003 0.04167 0.02396 0.01597 0.003939

1962 0.281 0.0803 0.04624 0.02674 0.01783 0.004396

1963 0.2807 0.07324 0.04162 0.02384 0.0159 0.003919

1964 0.2805 0.07327 0.04249 0.02486 0.01657 0.004075

1965 0.2806 0.07672 0.04468 0.02554 0.01702 0.004198

1966 0.2806 0.07871 0.04599 0.02632 0.01755 0.004327

1967 0.2809 0.0737 0.04281 0.0249 0.0166 0.004094

1968 0.2805 0.07634 0.04132 0.02377 0.01585 0.003896

1969 0.2841 0.08409 0.04756 0.02659 0.01773 0.004372

1970 0.2803 0.06884 0.0392 0.02267 0.01511 0.003727

1971 0.2843 0.08275 0.04559 0.02655 0.0177 0.004364

1972 0.2804 0.0736 0.04261 0.02417 0.01612 0.003963

1973 0.2806 0.07434 0.04313 0.0248 0.01653 0.004077

1974 0.282 0.07705 0.04545 0.0256 0.01707 0.004208

1975 0.2805 0.07549 0.04387 0.02567 0.01711 0.00422

1976 0.282 0.07702 0.04571 0.02641 0.01761 0.00433

1977 0.2805 0.07622 0.04404 0.02514 0.01676 0.004132

1978 0.2833 0.07139 0.04122 0.02355 0.0157 0.003871

1979 0.2812 0.08124 0.04613 0.02559 0.01706 0.004207

1980 0.2823 0.0739 0.04153 0.02397 0.01598 0.003929

1981 0.2805 0.07021 0.0408 0.02366 0.01578 0.00389

1982 0.2837 0.07462 0.04433 0.02558 0.01705 0.004205

1983 0.2805 0.0732 0.04104 0.02378 0.01585 0.003909

1984 0.2804 0.07044 0.04088 0.02293 0.01529 0.003759

1985 0.2808 0.07591 0.04396 0.0255 0.017 0.004192

1986 0.4 0.09431 0.04369 0.02578 0.01719 0.004238

1987 0.2832 0.07683 0.04226 0.02387 0.01591 0.003924

1988 0.2804 0.06877 0.03977 0.02287 0.01525 0.003749

1989 0.2893 0.08128 0.04762 0.0259 0.01727 0.004258

1990 0.2836 0.07953 0.0464 0.02607 0.01738 0.004285

Sorted results

Prob. Peak 96 hr 21 Day 60 Day 90 Day Yearly

0.032258064516129 0.4 0.09431 0.04762 0.02674 0.01783 0.004396

0.0645161290322581 0.2893 0.08409 0.04756 0.02659 0.01773 0.004372

0.0967741935483871 0.2843 0.08275 0.0464 0.02655 0.0177 0.004364

0.129032258064516 0.2841 0.08128 0.04624 0.02641 0.01761 0.00433

0.161290322580645 0.2837 0.08124 0.04613 0.02632 0.01755 0.004327

0.193548387096774 0.2836 0.0803 0.04599 0.02607 0.01738 0.004285

0.225806451612903 0.2833 0.07953 0.04571 0.0259 0.01727 0.004258

0.258064516129032 0.2832 0.07871 0.04559 0.02578 0.01719 0.004238

0.290322580645161 0.2823 0.07705 0.04545 0.02567 0.01711 0.00422
32

0.32258064516129 0.282 0.07702 0.04468 0.0256 0.01707 0.004208

0.354838709677419 0.282 0.07683 0.04433 0.02559 0.01706 0.004207

0.387096774193548 0.2812 0.07672 0.04404 0.02558 0.01705 0.004205

0.419354838709677 0.281 0.07634 0.04396 0.02554 0.01702 0.004198

0.451612903225806 0.2809 0.07622 0.04387 0.0255 0.017 0.004192

0.483870967741936 0.2808 0.07591 0.04369 0.02514 0.01676 0.004132

0.516129032258065 0.2807 0.07549 0.04313 0.0249 0.0166 0.004094

0.548387096774194 0.2806 0.07462 0.04281 0.02486 0.01657 0.004077

0.580645161290323 0.2806 0.07434 0.04261 0.0248 0.01653 0.004075

0.612903225806452 0.2806 0.0739 0.04249 0.02417 0.01612 0.003963

0.645161290322581 0.2805 0.0737 0.04226 0.02397 0.01598 0.003939

0.67741935483871 0.2805 0.0736 0.04167 0.02396 0.01597 0.003929

0.709677419354839 0.2805 0.07327 0.04162 0.02387 0.01591 0.003924

0.741935483870968 0.2805 0.07324 0.04153 0.02384 0.0159 0.003919

0.774193548387097 0.2805 0.0732 0.04132 0.02378 0.01585 0.003909

0.806451612903226 0.2805 0.07139 0.04122 0.02377 0.01585 0.003896

0.838709677419355 0.2804 0.07044 0.04104 0.02366 0.01578 0.00389

0.870967741935484 0.2804 0.07021 0.04088 0.02355 0.0157 0.003871

0.903225806451613 0.2804 0.07003 0.0408 0.02293 0.01529 0.003759

0.935483870967742 0.2804 0.06884 0.03977 0.02287 0.01525 0.003749

0.967741935483871 0.2803 0.06877 0.0392 0.02267 0.01511 0.003727

0.1 0.28428 0.082603 0.046384 0.026536 0.017691 0.0043606

Average of yearly averages: 0.00408843333333333

Inputs generated by pe5.pl - Novemeber 2006

Data used for this run:

Output File: SPIROTET

Metfile: w23234.dvf

PRZM scenario: CARowCropRLF_V2.txt

EXAMS environment file: pond298.exv

Chemical Name: Spirotetramat

Description Variable Name Value Units Comments

Molecular weight mwt 373.45 g/mol

Henry's Law Const. henry 6.90e-13 atm-m^3/mol

Vapor Pressure vapr 4.2e-11 torr

Solubility sol 33.5 mg/L

Kd Kd 4.39 mg/L

Koc Koc mg/L

Photolysis half-life kdp 14.4 days Half-life

Aerobic Aquatic Metabolism kbacw 0.2676 days Halfife

Anaerobic Aquatic Metabolism kbacs 2.1 days Halfife

Aerobic Soil Metabolism asm 0.298 days Halfife

Hydrolysis: pH 7 13.1 days Half-life

Method: CAM 2 integer See PRZM manual

Incorporation Depth: DEPI 0.0 cm

Application Rate: TAPP 0.1121 kg/ha

Application Efficiency: APPEFF 0.95 fraction

Spray Drift DRFT 0.05 fraction of application rate applied to pond

Application Date Date 10-02 dd/mm or dd/mmm or dd-mm or dd-mmm

Interval 1 interval 7 days Set to 0 or delete line for single app.

app. rate 1 apprate 0.1121 kg/ha

Interval 2 interval 7 days Set to 0 or delete line for single app.

app. rate 2 apprate 0.1121 kg/ha

Interval 3 interval 7 days Set to 0 or delete line for single app.

app. rate 3 apprate 0.1121 kg/ha

Interval 4 interval 7 days Set to 0 or delete line for single app.

app. rate 4 apprate 0.1121 kg/ha

Record 17: FILTRA

IPSCND 1

UPTKF 0

Record 18: PLVKRT 0

PLDKRT 0

FEXTRC 0.5

Flag for Index Res. Run IR EPA Pond

Flag for runoff calc. RUNOFF none none, monthly or total(average of entire run)
33

Appendix C. Agency risk quotient (RQ) metrics and levels of concern (LOC) 

per risk class

Risk Class Risk Description RQ LOC

Aquatic Animals (fish and invertebrates)

Acute Potential for effects to non-listed animals from acute 

exposures

Peak EEC/LC50

1

0.5

Acute 

Restricted Use

Potential for effects to animals from acute exposures

Risks may be mitigated through restricted use 

classification

Peak EEC/LC50

1

0.1

Acute Listed 

Species

Listed species may be potentially affected by acute 

exposures

Peak EEC/LC50

1

0.05

Chronic Potential for effects to non-listed and listed animals 

from chronic exposures 

60-day EEC/NOEC (fish) 1

21-day EEC/NOEC 

(invertebrates)

Terrestrial Animals (mammals and birds)

Acute Potential for effects to non-listed animals from acute 

exposures

EEC2/LC50 (Dietary) 0.5

EEC/LD50 (Dose)

Acute 

Restricted Use

Potential for effects to animals from acute exposures

Risks may be mitigated through restricted use 

classification

EEC2/LC50 (Dietary) 0.2

EEC/LD50 (Dose)

Acute Listed 

Species

Listed species may be potentially affected by acute 

exposures

EEC 2/LC50 (Dietary) 0.1

EEC/LD50 (Dose)

Chronic Potential for effects to non-listed and listed animals 

from chronic exposures

EEC 2/NOAEC 1

Plants

Non-Listed Potential for effects to non-target, non-listed plants 

from exposures

EEC/ EC25 1

Listed Plant Potential for effects to non-target, listed plants from 

exposures

EEC/ NOEC 1

EEC/ EC05

1 LC50 or EC50. 2 Based on upper bound Kenaga values.
34

Appendix D. Evaluation of the Nature of Non-Extracted Residues (NERs) in 

Spirotetramat Metabolism Studies (MRID 47576501)

Ramanarayanan, T. 2008. Nature and Fate of Non-Extractable Residues in Spirotetramat 

Soil Metabolism Studies. Unpublished study performed by Bayer CropScience 

Environmental Research, Stilwell, KS, and submitted by Bayer CropScience, RTP, NC. 

Report No. G201953.

Table 1. Environmental Fate Data Requirements for Spirotetramat

Guideline 

Number Data Requirement MRID#

Study 

Classification

Are Additional 

Data Needed 

for Risk 

Assessment?

Non-guideline Nature of NERs of Spirotetramat 47576501 Supplemental Yes1

1 The registrant should provide additional information characterizing the NERs. Unless proven otherwise, EFED 

will consider the NERs as repositories of toxic material.

Summary: Based upon the available data, the Environmental Fate and Effects Division (EFED)

believes that the un-extracted or non-extracted residues (NERs) do not contain parent, or the 

degradates of concern spirotetramat-enol or spirotetramat-ketohydroxy. However, the presence 

of other toxic chemicals cannot be precluded.13 Unless data are provided that proves otherwise, 

the NERs will continue to be considered repositories of possible toxic material. 

Background: Various aerobic and anaerobic soil and aquatic metabolism studies are available 

for spirotetramat, and for its major transformation product, spirotetramat-enol. These studies 

revealed moderate to rapid degradation of the test substances spirotetramat, spirotetramat-enol 

and spirotetramat-ketohydroxy, with formation of very high levels of NERs. In past assessments 

EFED regarded the formation of high levels of NERs in soils and sediments as an issue of 

concern, and the NERs were considered repositories of potentially toxic material. Thus, in its 

aquatic exposure assessments, the EFED used the rates of degradation of the parent material and

additionally, calculated half-lives for the total toxic residues (TTRs), which included parent 

compound, degradates of concern (spirotetramat-enol and spirotetramat-ketohydroxy), plus the 

NERs. This report submitted by the registrant (MRID 47576501), is a position paper intended to 

address the issue of the NERs.

In a past review (DP Barcodes D358765, D362966, dated 11/08/2010), it was stated that since at 

the time there were no exceedances of the aquatic levels of concern (LOCs), the issue of the 

NERs would be postponed and revisited in case there would be an exceedance of an LOC in a 

future assessment. Since in preliminary calculations there are exceedances of the aquatic LOCs 

for uses of spirotetramat, at this time EFED is re-evaluating the NER topic in this review.

Registrant’s Comments and Its Position on the Issue (MRID 47576501): According to the 

registrant, in aerobic soil metabolism studies, both spirotetramat and spirotetramat-enol degraded 

rapidly and formed very high levels of NERs (up to 58% AR). The extractions included 

 

13 A sediment toxicity study (Dorgerloh, 2005) that was conducted for a period of 28 days in a spiked water system 

shows high toxicity towards Chironomus riparius, and likely the sediments contained very high levels of NERs. 
35

aqueous/organic solvents and more aggressive extractions using strong acidic organic/aqueous 

solvents and/or heat (see EFED’s response on the use of high temperature). They argue that in

the environment, water is the only solvent, and the NERs cannot be expected to be released 

under these conditions. The NERs should not be considered as a relevant residue in aquatic 

exposure assessments.

It was also noted that in the soil photolysis study that used sterile soil, spirotetramat degraded to 

spirotetramat-enol (and spirotetramat-ketohydroxy in the irradiated samples), with very low 

formation of NERs (≤2.1% AR). In contrast, in the viable samples of a similar soil photolysis 

study, and the aerobic soil metabolism studies, spirotetramat degraded with rapid formation of 

high levels of NERs. The registrant believes that these results show that spirotetramat degrades 

to spirotetramat-enol via hydrolysis and biolysis, but that further degradation of spirotetramatenol is only biologically mediated and that formation of NERs in soil is due to the biological 

degradation of spirotetramat-enol. “[I]t can be concluded that NER from spirotetramat 

degradation would be a part of the soil organic matter and not be a relevant residue...”

EFED’s Response: The reason why the NERs are considered to be of concern in certain 

assessments is that in the environment, natural solvents, compounds in product formulations, and 

compounds from tank mixtures may keep pesticides, their transformation products, or both from 

binding to soil. In the laboratory, pesticide residues may not be studied in the presence of these 

solvents and may be kinetically inhibited from extraction by soil colloids that are not well 

disturbed by water, single organic solvents, or extraction conditions such as vigorous shaking, 

elevated temperatures, and sonication. Also, pesticide residues in the environment may undergo 

repeated extractions with water over longer time periods than are replicable in the laboratory. 

Conditions in laboratory tests do not reflect the changes in temperature and humidity that soils in 

the environment undergo. Also, plant roots actively modify soils and sediments, which can 

result in decreased compound binding to soil in the environment that is not replicated in the 

laboratory.

EFED noted that only in the aerobic soil metabolism study conducted for spirotetramat-enol, 

microwave extraction was conducted for 10 minutes at 70oC. In all other laboratory studies, 

other extractions were conducted mainly with acetonitrile/water solutions (at various ratios) and 

at RT. Exhaustive extractions of polar compounds should also involve use of multiple mild 

solvents with different chemical properties, since the transformation products may be less or 

more polar than the parent compound. A sterile treated system (sterilized using a method that 

does not alter the soil structure) with low NERs, may be evidence that the NERs at higher levels 

in a non-sterile treated system are not the test compound or its transformation products of 

concern. It appears from the studies performed with sterile soils that the extraction methods used 

were efficient in removing the available spirotetramat, spirotetramat-enol and spirotetramatketohydroxy from the sterile soils since low levels of NERs were observed in such studies. 

Spirotetramat-ketohydroxy was a minor component in the dark control samples, but it reached 

high levels in the irradiated samples; since the NERs were also low in the irradiated samples, 

extraction methods used also appear to be efficient in removing the available spirotetramatketohydroxy overall. Since similar extraction methods were used in the aerobic and anaerobic 

soil metabolism studies for spirotetramat (i.e., acetonitrile/water solutions), compared to the soil 

photolysis study, the methods were also likely efficient in removing the available spirotetramat,
36

spirotetramat-enol and spirotetramat-ketohydroxy from the viable soils; however, what was not 

extracted may be of concern. It is further noted that a closer inspection of the study shows that 

the sterilization method was autoclaving, a method of sterilization with a potential to change the 

properties and structure of the soil.

In order to evaluate the formation of NERs, several of the environmental fate study extraction 

methods were further inspected. In an aerobic soil metabolism study conducted with the parent 

compound, intended to follow only the decay of spirotetramat, since the chemical hydrolyzes 

rapidly in alkaline solutions, three extractions with acetonitrile/water (1:1, v/v, containing 0.5 % 

formic acid), followed by two extractions with acetonitrile/1N HCl (1:1, v/v, pH ca. 1), and with

acetonitrile (1 x 50 mL) were performed. Very high levels of NERs were observed.

In an another study, conducted with spirotetramat-enol, to follow only the degradates of 

spirotetramat, soil samples were extracted once with water containing 0.025% NH3 at RT (pH ~

7.0 to 8.5), followed by extraction three times with acetonitrile/water (1:1, containing 0.1 % 

ammonium chloride [w/v] and 0.06 % NH3 [v/v]; pH ~ 8.5) by shaking at RT, and finally an 

“aggressive” microwave extraction was performed at 70°C (only 10 min) using the same 

medium as above. Similarly, very high levels of NERs were observed in this study.

In the soil photolysis study that used sterile soils, the extractions occurred three times with

acetonitrile/water with 0.5% formic acid (1:1, v:v), shaken at RT for 30 minutes, then two times 

with acetonitrile/aqueous 1 N HCl (1:1, v:v) and once with acetonitrile. The acetonitrile extract 

contained <3% AR and was not processed further. The levels of NERs were high only in the 

viable soil study conducted separately (and prior to this study). This could indicate that the 

extraction were acceptable for the chemicals spirotetramat, spirotetramat-enol and spirotetramatketohydroxy, which are of concern. Both, the study conducted with the viable and sterile soils 

have been regarded as supplemental.

Finally, by comparison, in the method validation soils were mixed with [25 mL of a solution of 

ethyl acetate (5 %, v/v) and cysteine hydrochloride (8 g L-1) in water, 0.5 mL formic acid, 25 mL 

acetonitrile], fortified with 1 ml of 13C internal standard solution and extracted by microwave 

extraction (70 °C, 30 min). Extraction (without addition of internal standard) was repeated once. 

In the method validation, the recoveries of all the test compounds were appropriate; similar 

methods were used in the terrestrial field dissipation studies.

The parent spirotetramat shows very high solubilities in common solvents such as acetone, 

dichloromethane and ethyl acetate. None of these solvents were used in the soil metabolism 

studies. The degradates spirotetramat-enol and spirotetramat-ketohydroxy are likely more polar 

than the parent compound. In the environmental fate studies the extractions were performed 

mainly or solely in acetonitrile solutions and with one exception, at RT. It was noted that in the 

method validation, a solution containing ethyl acetate/cysteine hydrochloride/formic acid/

acetonitrile/water, was used in combination with high temperatures and a long extraction period 

(30 minutes). The nature of the non-extracted residues (NERs) has not been clearly elucidated in 

any of the metabolism studies. Instead, the remaining soils were fractionated to determine fulvic 

acid, humic acid and humin fractions. This methodology could be misleading and extractable 
37

residues may have been omitted and not measured. In short, the NERs were not elucidated in 

any of the studies and should be regarded as a source of toxic material.
38

Appendix E. Terrestrial Exposure Assessment for the New Uses of Spirotetramat 2012

Table D-1. Input parameters and upper-bound dose-based estimated environmental concentrations (EECs) generated using T-REX v1.5 for the 

maximum spirotetramat spray application scenarios of various crops for birds. 

Use

Max. 

Single App. 

Rate 

(lbs a.i./A)

Min. 

Interval 

(Days)

Max. No. 

Apps. Per 

Year

EECs in ppm

Size 

class1

Short 

Grass

Long 

Grass

Broadleaf 

Plants

Arthropods Fruits, 

Pods

Seeds

Parent only 2

Watercress 0.2 7 2

Small 67.23 30.81 37.82 26.33 4.2 0.93

Mid 38.34 17.57 21.57 15.02 2.40 0.53

Large 17.16 7.87 9.66 6.72 1.07 0.24

Banana/ 

Plantain 0.25 14 5

Small 72.15 33.07 40.58 28.26 4.51 1.00

Mid 41.14 18.86 23.14 16.11 2.57 0.57

Large 18.42 8.44 10.36 7.21 1.15 0.26

Total Residues 2

Watercress 0.2 7 3

Small 76.55 35.09 43.06 29.98 4.78 1.06

Mid 43.65 20.01 24.55 17.10 2.73 0.61

Large 19.54 8.96 10.99 7.65 1.22 0.27

Banana/ 

Plantain 0.25 14 2

Small 81.37 37.29 45.77 31.87 5.09 1.13

Mid 46.40 21.27 26.10 18.17 2.90 0.64

Large 20.77 9.52 11.68 8.14 1.30 0.29

a There are three size classes of birds including small (20g), medium (100g), and large (1000g). Small birds represent the most sensitive size class and therefore the lack of risk concern to small 

birds from upper-bound exposure concentrations implies that there will also not be risk to other sizes of birds. 

b

For foliar dissipation, 16 foliar half-life measurements are available from two guideline studies (MRID 46904508 and MRID 46904509) and one non-guideline study (MRID 46904507) for 

both the parent spirotetramat as well as for the total residues (parent spirotetramat, spirotetramat-enol, and spirotetramat-ketohydroxy). Assuming these values are distributed normally, the 

values which represent the one tail upper 90% confidence limit of the mean half-lives for the parent and total residue approaches are 3.3 and 5.3 days, respectively.
39

Table D-2. Input parameters and upper-bound dose-based estimated environmental concentrations (EECs) generated using T-REX v1.5 for the 

maximum spirotetramat spray application scenarios of various crops for mammals.

Use

Max. 

Single App. 

Rate 

(lbs a.i./A)

Min. 

Interval 

(Days)

Max. No. 

Apps. Per 

Year

EECs in ppm

Size 

classa

Short 

Grass

Long 

Grass

Broadleaf 

Plants

Arthropods Fruits, 

Pods

Seeds

Parent only b

Watercress 0.2 7 2

Small 56.28 25.80 31.66 22.04 3.52 0.78

Mid 38.90 17.83 21.88 15.24 2.43 0.54

Large 9.02 4.13 5.07 3.53 0.56 0.13

Banana/ 

Plantains 0.25 14 5

Small 60.40 27.68 33.97 23.66 3.77 0.84

Mid 41.74 19.13 23.48 16.35 2.61 0.58

Large 9.68 4.44 5.44 3.79 0.60 0.13

Total Residues b

Watercress 0.2 7 3

Small 64.08 29.37 36.05 25.10 4.01 0.89

Mid 44.29 20.30 24.91 17.35 2.77 0.62

Large 10.27 4.71 5.78 4.02 0.64 0.14

Banana/ 

Plantains 0.25 14 2

Small 68.12 31.22 38.32 26.68 4.26 0.95

Mid 47.08 21.58 26.48 18.44 2.94 0.65

Large 10.91 5.00 6.14 4.28 0.68 0.15

a There are three size classes of mammals including small (15g), medium (35g), and large (1000g). Small mammals represent the most sensitive size class and therefore the lack of risk concern 

to small mammals from upper-bound exposure concentrations implies that there will also not be risk to other sizes of birds. 

b

For foliar dissipation, 16 foliar half-life measurements are available from two guideline studies (MRID 46904508 and MRID 46904509) and one non-guideline study (MRID 46904507) for 

both the parent spirotetramat as well as for the total residues (parent spirotetramat, spirotetramat-enol, and spirotetramat-ketohydroxy). Assuming these values are distributed normally, the 

values which represent the one tail upper 90% confidence limit of the mean half-lives for the parent and total residue approaches are 3.3 and 5.3 days, respectively.
40

Table D-3. Input parameters and upper-bound dietary-based estimated environmental concentrations (EECs) generated using T-REX v1.5 for 

the maximum spirotetramat spray application scenarios of various crops for birds and mammals. 

Use

Max. Single App. 

Rate 

(lbs a.i./A)

Min. Interval 

(Days)

Max. No. Apps. Per 

Year

EECs in ppm

Short 

Grass

Long 

Grass

Broadleaf 

Plants

Arthropods

Fruits, 

Pods, 

Seeds

Parent only a

Watercress 0.2 7 2 59.03 27.06 33.21 23.12 3.69

Banana/ 

Plantains 0.25 14 5 63.35 29.03 35.63 24.81 3.96

Total Residues a

Watercress 0.2 7 3 67.22 30.81 37.81 26.33 4.20

Banana/ 

Plantains 0.25 14 2 71.44 32.74 40.19 27.98 4.47

a

For foliar dissipation, 16 foliar half-life measurements are available from two guideline studies (MRID 46904508 and MRID 46904509) and one non-guideline study (MRID 46904507) for 

both the parent spirotetramat as well as for the total residues (parent spirotetramat, spirotetramat-enol, and spirotetramat-ketohydroxy). Assuming these values are distributed normally, the 

values which represent the one tail upper 90% confidence limit of the mean half-lives for the parent and total residue approaches are 3.3 and 5.3 days, respectively.
41

Figure E-1. Parent only exposure levels from an application of spirotetramat to watercress.
42

Figure E-2. Total residue exposure levels from an application of spirotetramat to 

watercress.
43

Figure E-3. Parent only exposure levels from an application of spirotetramat to 

bananas/plantains.
44

Figure E-4. Total residue exposure levels from an application of spirotetramat to 

bananas/plantains.