Page 2 of 2 In the following sections, the specific argument presented by D AS is summarized in italics and is then followed by EFED ’s response

.

1. DAS’s comment : “DAS acknowledges that an independent laboratory validation for the specific water method (MRID 478242

- 01) is not available. However, an additional water method ( RH

- 2485 Analytical Method for Water ; MRID: 44617824) and its corresponding ILV ( Independent Laboratory Method Validation Trials of RH

- 2485 Analytical Method for Water ; MRID: 44617815) have been submitted to the USEPA. The two studies are in compliance with the OCSPP Guideline 850.6100. Therefore, DAS believes that the requirement for an ILV to meet guideline 850.6100 has already been met at this time by the submitted stu dy, and no additional study would be required

. . .” EFED’s response: EFED received the analytical method and independent laboratory validation provided by the registrant. Both studies: “ILV Trials Analytical Methods in Water RH

- 2485” and “RH

- 2485 Analytica l Method for Water” with MRIDs 492017

- 03 (previously 446178

- 24) and 492017

- 02 (previously 446178

- 15) respectively, are currently under review; therefore, no additional studies are required at this time.

2. DAS ’s comment :

“ DAS agrees that an anaerobic soil metabolism study has not been submitted to the EPA. DAS has an anaerobic soil metabolism study that was conducted for Europe that can potentially provide additional information for the risk assessment. We can provide the data for review should EPA req uire it for their registration review process. ” EFED’s response: EFED encourage s DAS to submit data that can potentially provide more information about the anaerobic metabolism of methoxyfenozide.

3. DAS’s comment:

“ In Section 4.1, Table 3, the chronic midge Chironomus riparius toxicity value is stated as NOAEC = 0.0063 mg a.i./L. However, the Acute

- to

- Chronic Ratio (ACR) that estimates the acute toxicity for the midge has used a chronic midge endpoint of NOAEC =0.0026 mg a.i./L. It is unclear how the NOAEC of 0.0026 mg a.i./L has been derived from the midge life cycle study, and DAS believes that the wrong number was used in the calculation. The NOAEC that is used in the ACR effects the estimated toxicity value for the acute midge and the subsequent risk

assessments. The toxicity value for the chronic midge is expected to be NOAEC = 0.0063 mg a.i./L and should be the number used for the ACR.” EFED’s response: EFED agrees that the source of the NOAEC of 0.0026 mg a.i./L used in the ACR calculations is unclear. After closer examination, it appears that EFED’s review of the midge lifecycle study (MRID 4 50328

- 01) will need to be revised to reflect a different NOAEC based on the measured concentrations in pore water ( 0.00 31 mg a.i./L )

. The NOAEC of 0.0063 mg a.i./L is based on nominal concentrations . Typically, the A gency prefers measured concentration values to nominal concentration values. T he value of 0 .0031 mg a.i./L is the 28

- day NOAEC based on concentrations in pore water

. This value should be used in the calculation of an ACR, and result s in a n EC 50 of 0.05 mg a.i./L

. The Agency notes that the NOAEC of 0.0031 mg a.i./L is not substantially different than the value of 0.0026 mg a.i./L which has been used in the past.