OFFICE OF 

CHEMICAL SAFETY AND 

POLLUTION PREVENTION

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

WASHINGTON D.C., 20460 

PC Code: 270000

                                                                                                             DP Barcode: 427320

MEMORANDUM

DATE:    May 29, 2015

SUBJECT:    Isofetamid: Status of Ecological Effects Data in Support of the Proposed Section 3

Uses

TO: Cynthia Giles‐Parker, Chief

Fungicide Branch

Registration Division

THROUGH: Dana Spatz, Branch Chief

Environmental Risk Branch III

Environmental Fate and Effects Division

FROM: Rosanna Louie‐Juzwiak, RAPL

Environmental Risk Branch III

Environmental Fate and Effects Division

ISK Biosciences has submitted an application to register a new chemical, isofetamid, which is being

proposed for use on almond, lettuce, grapes (Subgroup 13‐07F), low growing berries (Subgroup 13‐07G),

rapeseed (Subgroup 20A), and turf (commercial and residential).  One technical product (EPA File

Symbol 71512‐ER) and two end‐use products [Isofetamid 400SC Fungicide (EPA File Symbol 71512‐EE)

and Isofetamid Turf Fungicide (EPA File Symbol 71512‐EG)] are being proposed for registration in the

United States.  The maximum proposed single application rate is 0.572 lb a.i./acre (grapes) and the

maximum annual application rate proposed is 3.65 lb a.i./acre (turf).  Application methods include

ground spray, aerial spray, and chemigation. ISK Biosciences also submitted a request1 to waive the

submission of an acute fish toxicity study conducted with a Fathead minnow (OCSPP 850.1075) and for a

fish early‐life stage toxicity study conducted with a Rainbow trout, Bluegill sunfish, or carp (OCSPP

850.1400).

 

1

 Email correspondence from M. Peplowski of ISK Biosciences to H. Garvie of the Registration Division on May 

26, 2015. 
The Environmental Fate and Effects Division (EFED) has completed the ecological risk assessment for the

Section 3 registration decision on the new broad‐spectrum, systemic fungicide isofetamid (IKF‐5411) (PC

Code 270000). As part of this assessment, EFED discussed uncertainties in the risk conclusions attributed

to the lack of certain studies (required per 40 CFR Part 158) that were not available at the time of the

assessment. Overall, based on the available data and predicted exposures in the environment, EFED

believes that the submission of the following studies would not alter the risk conclusions for the

proposed uses (with the exception of the proposed wet‐harvested cranberry use), and in the context of

the assessed application rates and uses, would concur with waiving the following data requirements

(refer to the detailed discussion for each data requirement, below):

‐ OCSPP Guideline 850.1400: Fish Early‐life Stage (freshwater) conducted with a Rainbow trout,

Bluegill sunfish, or carp

‐ OCSPP Guideline 850.1075: Acute Freshwater Fish Toxicity Study conducted with a Fathead

minnow

Fish early‐life stage study. Currently, no acute data are available for the freshwater fish species used in

the chronic study (i.e., fathead minnow), therefore, there is uncertainty regarding the chronic

freshwater fish endpoint. Although the percent of the reduction in length was small compared to the

negative control (0.39%), it was statistically significant and the reductions in length followed a dose‐

response trend.  There were no significant effects on hatching success or larval survival at any

concentration tested.  However, additional chronic freshwater fish data would not be expected to alter

the risk conclusions for the proposed uses (i.e., minimal risk to fish from chronic exposure, except for

the proposed wet‐harvested cranberry use) because of the relatively low toxicity of isofetamid to fish

and the low estimated environmental concentrations (EECs) for the proposed non‐flooded crop uses for

isofetamid.  

Acute fish toxicity study, freshwater. Currently, no chronic data are available for the freshwater fish used

in the acute toxicity studies (i.e., Rainbow trout, Bluegill sunfish, or carp). While there is uncertainty on

whether the fathead minnow tested in the available early‐life stage study is more or less sensitive than

rainbow trout (the most sensitive freshwater fish tested on an acute‐basis), the available acute toxicity

data for freshwater fish suggests that isofetamid would pose low risk on an acute exposure basis.