OFFICE OF CHEMICAL SAFETY AND POLLUTION PREVENTION UNITED STATES ENVIRONMENTAL PROTECTION AGENCY WASHINGTON D.C., 20460



### PC Code: 129223 DP Barcode: 419898

April 21 , 2015

MEMORANDUM

SUBJECT: Ecological Risk Assessment for the Proposed New Use of Sedaxane as a Seed Treatment on Sugar B eet and Cotton

TO: Cynthia Giles

- Parker, Chief Fungicide Branch Registration Division (7505P)

THROUGH: Dana Spatz, Branch Chief Environmental Risk Branch 3 Environmental Fate and Effects Division

FROM: Katherine Stebbins, Biologist Environmental Risk Branch 3 Environmental Fate and Effects Division (7507P)

PEER REVIEW: Rosanna Louie

- Juzwiak, RAPL Environmental Risk Branch 3 Environmental Fate and Effects Division

Syngenta is proposing the use of sedaxane as a seed treatment on cotton and sugar beet. The proposed new uses are only included on the label for Sedaxane 500FS/Vibrance TM 

### (A16148C; EPA Reg. No. 100

- 137)

— the single active ingredient formulation. The proposed application rates for cotton and sugar beet are provide in Table 1

. For these new uses , up to two applications may be made per year, which permits an initial planting of sedaxane treated seeds followed by either replanting of treated seeds in the event of crop failure or from multiple plantings as part of a crop rotation.

### Table 1 . Proposed Sedaxane Application Rates

Crop MaxApp Rate lb a.i./ 100 lb of

seed Max Seeding

Rate a lb seed /A Max Single App Rate lb a.i./A (kg a.i./ha) Max Total App Rate Max Number of AppsPHI (days)bREI (hours)bMRI (days)b Minimum Planting Depth in

Inches Per Year lb a.i./A Per Year lb a.i./A

Cotton 0.02 18.8 c 0.004 (0.004) 0.008 2 NS 12 0 1 (Texas A&M AgriLife extension Sugar beet except those
grown for seed 0.36 4.8 d 0.017 (0.019) 0.034 2 NS 12 0 1 (MSU Extension)

a. The maximum seeding rate was developed based on data provided by BEAD

— J. Becker; S. Ratnayake. Acres Planted per Day and Seeding Rates of Crops Grown in the United States

, March 24, 2011

. b. PHI

– Preharvest interval; REI

– reentry interval; MRI

– Minimum retreatment interval

c. 1 lb seed/4,500 seeds x 85,000 seeds/A = 18.8 lb seed/A d. 1 lb seed/22,000 seeds x 104,544 seeds/A (processing sugar beets) = 4.8 lb seed/A NS= not specified



### Sedaxane is currently used to protect against certain soil

- borne and seed

- borne diseases. Registered uses include seed treatment s for : small grain cereals (barley, wheat, oats, rye and triticale), soybean, canola, corn, sorghum, dried shelled pea and bean (Subgroup 6C; except soybe an), rapeseed (subgroup 20A), and potato. In t he latest ecological risk assessment for corn, sorghum , dried shelled peas and beans, chick peas, lentils, fava beans, rapeseed subgroup and potato pieces ( 03/21/13; DP: 405155, 407045)

, 1 

### there were no LOC exceedances or risks identified for aquatic or terrestrial organisms at the two highest application rates (corn: 0.013 lb a.i./A applied up to two times; potato: 0.1 lb a.i./A applied once). For the proposed uses on cotton and sugarbeet, both the rates are lower than the highest previously assessed rate (potato) and the proposed sugarbeet rates are close to those previously assessed for cotton, thus, given the conclusions from the past assessment were that risk to aquatic and terrestrial organisms is considered low (no LOC exceedances) , additional assessment is not needed for this

new use.

At this time there are insufficient data to conduct a Tier 1 assessment for risk to pollinators. Given that there are currently only the acute contac t and oral studies available for the honeybee

, and that sed a x ane has systemic properties, the exposure and risk to pollinators cannot be precluded or fully assessed at this time. The additional data that are needed for conducting a pollinator assessment are summarized in Table 2

.

1 U.S. EPA. (2013) Ecological Risk Assessment for New Seed Treatment Uses of Sedaxane including Corn, Sorghum, Dried shelled Peas and Beans, Chick peas, Lentils, Fava beans, Rapeseed subgroup and Potato pieces. March 21, 2013.



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### Table 2. Recommendations for Bee Exposure and Effects Testing

Number Study Type Is Study Needed

Tier 1 (Non

- guideline, OECD TG 237) Honey bee larvae acute oral toxicity Yes

N o data are available to assess potential larval toxicity

Tier 1 (Non

- guideline) Honey bee adult chronic oral toxicity Yes

N o data are available to assess potential chronic toxicity to adult honey bees

Tier 1 (Non

- guideline) Honey bee larvae chronic oral toxicity Yes

N o data are available to assess potential larval toxicity

Tier 2 (Non

- guideline) Field trial of residues in pollen and
nectar Yes , In Reserve

N o data are available to determine the amount of residues that may occur in pollen and nectar

Tier 2 1 (Non

- guideline, OECD Guidance 75) Semi

- field testing for pollinators (tunnel or colony feeding studies) Yes, In Reserve

These data may be needed to inform on potential toxicity to honey bees from exposure to

sedaxane

- treated plants

Tier 2 1 (Guideline 850.3030) Honey bee toxicity of residues on foliage No

Based on the existing acute contact adult honey bee study ( i.e. 48

- hour

LD 50 >98.2 ug a.i./bee) does not trigger the need for this study

Tier 2 and 3 1 (Guideline 850.3040) Field testing for pollinators Yes, In Reserve

These data may be needed to inform on potential toxicity to honey bees from exposure to sedaxane

- treated crops (seed treatment)
1 Higher tier studies (Tier 2 and Tier 3) may be needed pending the results and evaluation of Tier 1 studies. Higher tier studies may be needed if the ratio of the EEC and larval or adult bee acute LD 50 > 0.4 or the ratio of the EEC and chronic NOAEC >1. Incident data and/or compelling open literature studies can also serve as rationale for requiring Tier 2 and Tier 3 studies.



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