Document ID: EPA-HQ-OPP-2013-0242-0025
Agency: epa
Document Type: Supporting & Related Material
Title: 
Posted Date: 2017-09-07T04:00Z

EPA Call with WSDA on Modified Shank Method
August 25, 2017; 11 am ET/8 am PT

EPA/OPP Participants
Cathryn Britton, Dana Friedman, Julie Javier, Leigh Rimmer, Shalu Shelat, Billy Smith 

EPA/R10
Dirk Helder, Derrick Terrada
WSDA
Tom Hoffmann, Joel Kangiser, Tim Schultz

Background
In April 2017, Tom Hoffmann contacted OPP to discuss a potential alternative application method for metam soil fumigations.  Participants from EPA/OPP and R10 held a teleconference with WSDA on April 11, 2017 to better understand the purpose of the alternate method.  WSDA cited difficulty with the availability of 1,3-dichloropropene, and noted problems with weed control as growers in the Pacific Northwest have moved from water-run application methods to shank.  At that time, it was noted that growers were starting to build prototype, dual-level blade shanks.  WSDA said they would contact EPA to revisit this issue in the fall.
Meeting Summary
On August 25, 2017, participants from EPA/OPP and R10 held a teleconference with WSDA as fumigation was pushed to earlier in the season due to earlier onset of cooler weather.  WSDA expressed growers' desire to utilize the prototype shanks for applications this season, and were looking to EPA for input on current label language related to types of application methods, buffer zone tables, and soil sealing.
The Agency's opinion was that the modified shank equipment itself, if followed immediately by compaction (e.g. by ring roller) would be supported by currently available shank data.  However, WSDA proposed that the modified shank be followed by incorporation using a rotary tiller before compaction.  Given that there are data supporting rotary tiller incorporated methods, EPA stated the proposed method is more in-line with the currently existing data that was used to generate the rotary tiller/spray blade buffer zone tables.
EPA raised the idea of conducting a new flux study to support new buffer tables for this modified method.  WSDA noted they would consider this, and discuss this issue in greater detail offline.